阅读说明：本技术 微脉冲激光雷达及对大气水汽、温度、压力探测的方法 (Micro-pulse laser radar and method for detecting atmospheric water vapor, temperature and pressure ) 是由 洪光烈 王建宇 于 2021-08-19 设计创作，主要内容包括：本发明涉及一种微脉冲激光雷达及对大气水汽、温度、压力探测的方法,微脉冲激光雷达包括第一发射机、第二发射机、第三发射机、光路传输模组、水汽通道探测模块、压力通道探测模块以及温度通道探测模块,多通道数据累积器、处理机、脉冲发生器；对大气水汽、温度、压力探测的方法为,由处理机对各发射机发射的多波长的连续激光进行斩波,得到多波长的脉冲激光；使多波长的脉冲激光按照既定的光路进行传输,同时对大气进行水汽、温度和压力的综合探测,使三大参数在反演过程中可以互为输入条件,提高了迭代速度和反演精度。(The invention relates to a micro-pulse laser radar and a method for detecting atmospheric water vapor, temperature and pressure, wherein the micro-pulse laser radar comprises a first transmitter, a second transmitter, a third transmitter, a light path transmission module, a water vapor channel detection module, a pressure channel detection module, a temperature channel detection module, a multi-channel data accumulator, a processor and a pulse generator; the method for detecting atmospheric water vapor, temperature and pressure comprises the steps that a processor chops multi-wavelength continuous lasers emitted by each transmitter to obtain multi-wavelength pulse lasers; the multi-wavelength pulse laser is transmitted according to a set light path, and meanwhile, the comprehensive detection of water vapor, temperature and pressure is carried out on the atmosphere, so that three parameters can be input conditions mutually in the inversion process, and the iteration speed and the inversion precision are improved.)

1. A micro-pulse lidar, comprising:

the first transmitter, the second transmitter and the third transmitter are respectively used for transmitting laser with different wavelengths;

the light path transmission module is arranged on the transmission light path of the lasers with different wavelengths, is used for synthesizing the lasers with different wavelengths into a laser beam and guiding the laser beam to atmosphere, and is also used for receiving backscattered echo light excited by the atmosphere, converting the backscattered echo light into parallel echo light beams and separating the parallel echo light into vapor echo light, pressure echo light and temperature echo light to be emitted respectively;

the water vapor channel detection module, the pressure channel detection module and the temperature channel detection module are respectively arranged on transmission light paths of water vapor echo light, pressure echo light and temperature echo light; the water vapor channel detection module is used for receiving and detecting the number of water vapor photons in the water vapor echo light, the pressure channel detection module is used for receiving and detecting the number of pressure photons in the pressure echo light, and the temperature channel detection module is used for receiving and detecting the first temperature photon number and the second temperature photon number in the temperature echo light;

the data processing control module is connected with the first transmitter, the second transmitter, the third transmitter, the water vapor channel detection module, the pressure channel detection module and the temperature channel detection module, is used for acquiring data of the water vapor channel detection module, the pressure channel detection module and the temperature channel detection module and performing inversion calculation in a unified manner on one hand, and is used for controlling the injection current and the working temperature of the first transmitter, the second transmitter and the third transmitter and chopping the output continuous wave laser into pulse laser to coordinate with the time sequence of the system on the other hand;

the data processing control module comprises:

the input end of the multi-channel data accumulator is respectively connected with the water vapor channel detection module, the pressure channel detection module and the temperature channel detection module, the output end of the multi-channel data accumulator is connected with the processor, and the multi-channel data accumulator is used for transmitting the water vapor photon number, the pressure photon number, the first temperature photon number and the second temperature photon number to the processor for unified inversion calculation;

the processor is also connected with a pulse generator, and the pulse generator is respectively connected with the first transmitter, the second transmitter and the third transmitter and used for providing chopping pulses for the first transmitter, the second transmitter and the third transmitter;

the processor comprises at least one processor connected with the first transmitter, the second transmitter and the third transmitter and used for forming a servo unit and adjusting the injection current and the working temperature of the first transmitter, the second transmitter and the third transmitter; the processor is also used to coordinate the timing of the pulse generator and the data accumulator.

2. The micro-pulse lidar of claim 1, wherein the optical path transmission module comprises:

a total reflection mirror arranged in the transmission direction of the light output by the first transmitter for turning 90 the laser light of the first transmitter^°；

The polarization beam combiner is arranged at the intersection of the transmission direction of the light output by the second transmitter and the transmission direction of the light output by the total reflection mirror and is used for orthogonally polarizing and combining the laser of the first transmitter and the laser of the second transmitter;

the first dichroic filter is arranged at the intersection of the light path of the third transmitter and the light path of the polarization beam combiner and is used for combining the laser beams of the first transmitter, the second transmitter and the third transmitter;

the beam expander, the axial cone, the first lens, the telescope and the input/output optical window are sequentially arranged on a transmission light path of the laser beam combination; after the laser combination beams are sequentially collimated, converted by the annular light spots, converged and parallel processed, parallel laser beams containing lasers with wavelengths of 765nm, 770nm and 825.5nm are obtained and enter atmosphere, the parallel laser beams are excited by the atmosphere to generate backscatter echo beams, the backscatter echo beams are returned to the first lens through an input/output optical window to be parallel processed, and then are sequentially processed by a hollow reflector, a second dichroic filter and a small-angle interference filter;

the second dichroic filter separates the 825.5nm water vapor echo light in the parallel echo light beam and sends the water vapor echo light to the water vapor channel detection module;

the small-angle interference filter separates 765nm pressure echo light in the parallel echo light beams and sends the separated 765nm pressure echo light to the pressure channel detection module, and sends 770nm temperature echo light to the temperature channel detection module.

3. The micro-pulse lidar according to claim 2, wherein the hollow mirror is provided with a hollow portion for allowing the light beam of the annular light spot emitted from the axial cone to pass through without obstruction, and an outer peripheral mirror for allowing the parallel echo light beam to be folded by 90 degrees^°。

4. The micro-pulse lidar of claim 1, wherein the moisture channel detection module comprises:

the first optical filter assembly is arranged in the transmission direction of the water vapor echo light and used for inhibiting the ambient light;

a second lens disposed in a transmission direction of light output from the first filter assembly;

and the first single photon counter is arranged in the convergence direction of the light output by the second lens and is used for detecting the number of water vapor photons in the water vapor echo light.

5. The micro-pulse lidar of claim 1, wherein the pressure channel detection module comprises:

a second filter assembly disposed in a transmission direction of the pressure echo light, for suppressing ambient light;

a third lens disposed in a transmission direction of light output from the second filter assembly;

and the second single photon counter is arranged in the convergence direction of the light output by the third lens and is used for detecting the number of pressure photons in the pressure echo light.

6. The micro-pulse lidar of claim 1, wherein the temperature channel detection module comprises:

a third filter assembly provided in the transmission direction of the temperature echo light to suppress ambient light;

70/30 beam splitting sheet, which is arranged in the transmission direction of the light output by the third optical filter assembly and divides the temperature echo light into 30% temperature echo light and 70% temperature echo light;

a fourth lens provided in a transmission direction of the 30% temperature echo light;

the third single photon counter is arranged in the convergence direction of the light output by the fourth lens and is used for detecting the first temperature photon number in the 30% temperature echo light;

the first potassium atomic gas absorption pool is arranged in the transmission direction of the 70% temperature echo light;

a fifth lens arranged in the transmission direction of the light output by the first potassium atomic gas absorption cell;

and the fourth single photon counter is arranged in the convergence direction of the light output by the fifth lens and is used for detecting the second temperature photon number in the 70% temperature echo light.

7. A method for detecting atmospheric moisture, temperature and pressure by using the micro-pulse laser radar as claimed in any one of claims 1 to 6, wherein the method for detecting atmospheric moisture, temperature and pressure comprises the following steps:

respectively emitting laser with different wavelengths by using a first transmitter, a second transmitter and a third transmitter, and synthesizing the laser with different wavelengths into a laser beam;

directing the laser beam to the atmosphere and obtaining a backscattered echo beam excited by the atmosphere;

converting the backward scattering echo light beam into a parallel echo light beam, and separating the parallel echo light beam into vapor echo light, pressure echo light and temperature echo light;

respectively detecting the water vapor echo light, the pressure echo light and the temperature echo light to obtain a water vapor photon number, a pressure photon number, a first temperature photon number and a second temperature photon number;

and transmitting the water vapor photon number, the pressure photon number, the first temperature photon number and the second temperature photon number to a processor for carrying out unified inversion calculation to obtain the atmospheric water vapor, the temperature and the pressure.

8. The method for detecting atmospheric water vapor, temperature and pressure according to claim 7, wherein the first transmitter, the second transmitter and the third transmitter are used for respectively transmitting laser beams with different wavelengths, and the laser beams with different wavelengths are combined into a laser beam; directing the laser beam to the atmosphere and obtaining an excited atmosphere backscatter echo beam; converting the backscattered echo light beams into parallel echo light beams, and separating the parallel echo light beams into water vapor echo light, pressure echo light and temperature echo light specifically comprises the following steps:

transmitting laser to a holophote by using a first transmitter, and turning the laser to a polarization beam combiner through the holophote;

transmitting laser to the polarization beam combiner by using a second transmitter, and vertically intersecting the laser transmitted by the first transmitter to synthesize a beam which is folded to the first dichroic film;

transmitting laser to the first dichroic filter by using a third transmitter, and combining the laser and a laser beam consisting of the laser of the first transmitter and the laser of the second transmitter into one beam;

the beam expander is used for collimating the laser beam and converting the laser beam into a circular beam through the axial cone;

the circular light beam penetrates through the hollow part of the hollow reflector, and the circular light beam is converged at the focus of the telescope by using the lens;

expanding the beam diameter of the circular light beam by multiple times by using a telescope, and reducing the divergence angle of the circular light beam to obtain a parallel light beam;

the parallel light beam is made to enter the atmosphere by using the input/output optical window, and the atmosphere backscattered echo light beam excited by the parallel light beam is received by using the input/output optical window.

Collecting the echo light at the focus of a telescope by using the telescope, and reducing the backscattered echo light beam into a parallel echo light beam by using a lens;

reflecting the parallel echo light beams to a second dichroic filter by utilizing the peripheral mirror surface of the hollow reflector;

separating water vapor echo light from the parallel echo light beams by using a second dichroic filter, and sending the rest parallel echo light beams to a small-angle interference filter;

and separating the pressure echo light by using a small-angle interference filter, and simultaneously obtaining temperature echo light.

9. The method for detecting atmospheric water vapor, temperature and pressure according to claim 8, wherein the step of detecting the water vapor echo light, the pressure echo light and the temperature echo light respectively to obtain a water vapor photon number, a pressure photon number, a first temperature photon number and a second temperature photon number specifically comprises:

receiving the water vapor echo light detection through a water vapor channel detection module to obtain a water vapor photon number;

receiving the pressure echo light detection through a pressure channel detection module to obtain the number of pressure photons;

and receiving the temperature echo light detection through a temperature channel detection module to obtain a first temperature photon number and a second temperature photon number.

Technical Field

The invention relates to the field of low-light-level detection in the optical communication industry, in particular to a micro-pulse laser radar and a method for detecting atmospheric water vapor, temperature and pressure.

Background

Atmospheric temperature and water vapor are important atmospheric thermodynamic parameters, and in terms of spatial and temporal distribution, thermodynamic profile data of atmospheric troposphere still has a great demand gap. Pressure plays a very important role in a range of atmospheric processes related to atmospheric dynamics. Such as low pressure, high pressure, low pressure groove, high pressure ridge information are all introduced into the atmospheric mode. Scholars in 1987 have indicated that the main limitation on the accuracy of weather models is the sparsity of the geographical distribution of the atmospheric pressure data being input. The observation data of the atmospheric pressure data in large-area oceans, inland large-area deserts, gobi and even plateau areas are sparse. In terms of time, the radio sounding balloon can only be released at fixed times twice a day; in terms of space, radiosonde sounding can only be performed at fixed weather stations. The development of a foundation, cheap, networkable and widely distributed active remote sensing instrument is a demand for the development of meteorological services.

At present, the differential absorption lidar system is considered to have the most potential to fill gaps of troposphere atmospheric thermodynamic and kinetic profile observation data; the differential absorption laser radar can successfully detect the content of atmospheric tropospheric water vapor, a laser taking Alexandrite as a mainstream or a dye laser pumped by a solid laser is taken as an emission light source, a photomultiplier can still act as a detector in the waveband, and a representative system is an onboard LEANDRE II instrument in France. The water vapor differential absorption laser radar with 820nm wave band is developed later, a titanium sapphire laser or a titanium sapphire optical amplifier is used as a transmitter core, a silicon avalanche diode is used as a detector, such as a vehicle-mounted scanning laser radar of Hohenheim university in Germany, and a two-dimensional or three-dimensional water vapor distribution structure between 300m and 4km of a troposphere can be obtained; an LASE airborne system developed by the NASA Lanli research center emits 100 + 150mJ of energy, the repetition frequency is 5Hz, and the precision of measuring the water-vapor mixing ratio can reach 6% or 0.01 g/kg; the differential absorption lidar of the BurMetelorlogie und Klimaftschung institute, Germany, can detect the vertical distribution of atmospheric moisture between 3km and 12km altitudes.

Although the differential absorption lidar has been successfully used for vertical profile detection of atmospheric moisture, the differential absorption lidar has not been successfully implemented for atmospheric temperature profile detection. The reason is that the absorption spectrum line of the temperature expressive gas-oxygen is narrow, so that the rayleigh backscattering spectrum width of the laser can be compared with the absorption spectrum line width of the oxygen, and therefore, the proportion of the atmospheric backscattering echo relative to rayleigh backscattering and mie backscattering is very important for the numerical inversion of the atmospheric temperature vertical profile of the differential absorption laser radar.

The Raman laser radar system based on the inelastic backscattering can detect the atmospheric temperature by using a rotating Raman technology and can measure the atmospheric water-vapor mixing ratio by using a vibrating Raman technology. The inefficiency of Raman backscattering causes the lidar system to require a higher (transmit) power x (receive) aperture area. The pulse energy of 532nm laser is not less than 300mJ, the pulse repetition frequency is not more than 50Hz, the pulse time width is about 10ns, and the diameter of the telescope primary mirror is not less than 500 mm. 4 sets of Raman laser radar systems in the world, a Caeli laser radar system of the Netherlands meteorological institute, a RAMMO system of Switzerland, a Raman laser radar system of Germany atmospheric radiometric project and a DRAMSES laser radar system all show that the signal-to-noise ratio of the Raman laser radar in daytime is very low, and a radio sounding method is frequently needed for calibrating, maintaining and maintaining the Raman laser radar system at high cost.

The absorption difference laser radar and the Raman laser radar transmitter both adopt lasers with low repetition frequency and high pulse energy, the high peak power of laser pulse has the risk of human eye injury, the size and the power consumption of the lasers are high, and the laser radar is one of the reasons of high cost. Therefore, a laser radar capable of simultaneously detecting atmospheric moisture, temperature, and pressure has not been widely used so far.

Disclosure of Invention

The invention aims to provide a micro-pulse laser radar and a method for detecting atmospheric water vapor, temperature and pressure, which solve two problems in the prior laser transmitter: the peak power of the transmitted pulse is very high, the power consumption is very high, the safety risk exists to human eyes, and the establishment and maintenance cost is very high; and a composite micro-pulse laser radar capable of performing inversion calculation on atmospheric water vapor, temperature and pressure is lacked, so that the iteration speed and the inversion accuracy need to be improved.

In order to achieve the above object, the present invention provides a micro-pulse lidar comprising:

the first transmitter, the second transmitter and the third transmitter are respectively used for transmitting different lasers;

the optical path transmission module is arranged on a transmission optical path of the laser with different wavelengths, is used for combining the laser with different wavelengths into one beam and guiding the beam to atmosphere, and is also used for receiving an excited atmosphere backscatter echo beam, converting the backscatter echo beam into a parallel echo beam and separating the parallel echo beam into vapor echo light, pressure echo light and temperature echo light;

the water vapor channel detection module, the pressure channel detection module and the temperature channel detection module are respectively arranged on transmission light paths of water vapor echo light, pressure echo light and temperature echo light; the water vapor channel detection module is used for receiving and detecting the number of water vapor photons in the water vapor echo light, the pressure channel detection module is used for receiving and detecting the number of pressure photons in the pressure echo light, and the temperature channel detection module is used for receiving and detecting the first temperature photon number and the second temperature photon number in the temperature echo light;

the data processing control module is connected with the first transmitter, the second transmitter, the third transmitter, the water vapor channel detection module, the pressure channel detection module and the temperature channel detection module, and is used for acquiring data of the water vapor channel detection module, the pressure channel detection module and the temperature channel detection module and performing inversion calculation in a unified manner; on the other hand, the system is used for controlling the injection current and the working temperature of the first transmitter, the second transmitter and the third transmitter and chopping the output continuous wave laser into pulse laser to coordinate with the time sequence of the system;

the data processing control module comprises:

the input end of the multi-channel data accumulator is respectively connected with the water vapor channel detection module, the pressure channel detection module and the temperature channel detection module, the output end of the multi-channel data accumulator is connected with the processor, and the multi-channel data accumulator is used for transmitting the water vapor photon number, the pressure photon number, the first temperature photon number and the second temperature photon number to the processor for unified inversion calculation;

the processor is also connected with a pulse generator, and the pulse generator is respectively connected with the first transmitter, the second transmitter and the third transmitter and used for providing chopping pulses for the first transmitter, the second transmitter and the third transmitter;

the processor comprises at least one processor connected with the first transmitter, the second transmitter and the third transmitter and used for forming a servo unit and adjusting the injection current and the working temperature of the first transmitter, the second transmitter and the third transmitter; the processor is also used to coordinate the timing of the pulse generator and the data accumulator.

The invention also provides a method for detecting atmospheric water vapor, temperature and pressure by using the micro-pulse laser radar, which comprises the following steps:

s1, respectively emitting laser with different wavelengths by using a first transmitter, a second transmitter and a third transmitter, and synthesizing the laser with different wavelengths into a laser beam;

s2, guiding the laser beam to the atmosphere and acquiring an excited atmosphere backscatter echo beam;

s3, converting the back scattering echo light beam into a parallel echo light beam, and separating the parallel echo light beam into vapor echo light, pressure echo light and temperature echo light;

s4, detecting the water vapor echo light, the pressure echo light and the temperature echo light respectively to obtain a water vapor photon number, a pressure photon number, a first temperature photon number and a second temperature photon number;

and S5, transmitting the water vapor photon number, the pressure photon number, the first temperature photon number and the second temperature photon number to a processor for carrying out unified inversion calculation to obtain the atmospheric water vapor, the temperature and the pressure.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects: the invention provides a micro-pulse laser radar which comprises a first transmitter, a second transmitter, a third transmitter, a light path transmission module, a water vapor channel detection module, a pressure channel detection module, a temperature channel detection module, a multi-channel data accumulator, a processor and a pulse generator, wherein the first transmitter is connected with the second transmitter through a power line; the method for detecting atmospheric water vapor, temperature and pressure by using the micro-pulse laser radar is characterized in that a processor performs chopping on multi-wavelength continuous laser emitted by each transmitter to obtain multi-wavelength pulse laser; the multi-wavelength pulse laser is transmitted according to a set light path, and meanwhile, the comprehensive detection of water vapor, temperature and pressure is carried out on the atmosphere, so that three parameters can be input conditions mutually in the inversion process, and the iteration speed and the inversion precision are improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic diagram of a micro-pulse laser radar according to the present invention;

FIG. 2 is a schematic diagram of a micro-pulse laser radar according to the present invention;

FIG. 3 is a block diagram of a 1530nm seed laser source according to the present invention;

FIG. 4 is a block diagram of a 1540nm seed laser source according to the present invention;

FIG. 5 is a block diagram of a 1651nm seed laser source according to the present invention;

FIG. 6 is a block diagram of a first pulsed pump source 3-8 and a second pulsed pump source 3-10;

FIG. 7 is a block diagram of the filter assemblies 5-1, 6-1 and 7-1.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide a micro-pulse laser radar and a method for detecting atmospheric water vapor, temperature and pressure, which solve two problems in the prior laser transmitter: the peak power of the transmitted pulse is very high, the power consumption is very high, the safety risk of human eyes exists, and the establishment and maintenance cost is very high; and a composite micro-pulse laser radar capable of performing inversion calculation on atmospheric water vapor, temperature and pressure is lacked, so that the iteration speed and the inversion accuracy need to be improved.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

The first embodiment is as follows:

a micro-pulse lidar comprising:

the first transmitter 1, the second transmitter 2 and the third transmitter 3 are respectively used for transmitting laser with different wavelengths;

the optical path transmission module 4 is arranged on a transmission optical path of the laser with different wavelengths, is used for synthesizing the laser with different wavelengths into a laser beam and guiding the laser beam to the atmosphere, is also used for receiving an excited atmosphere backscatter echo beam, converting the backscatter echo beam into a parallel echo beam and separating the parallel echo beam into a water vapor echo light, a pressure echo light and a temperature echo light to be respectively emitted;

the water vapor channel detection module 5, the pressure channel detection module 6 and the temperature channel detection module 7 are respectively arranged on transmission light paths of water vapor echo light, pressure echo light and temperature echo light; the water vapor channel detection module 5 is used for receiving and detecting the number of water vapor photons in the water vapor echo light, the pressure channel detection module 6 is used for receiving and detecting the number of pressure photons in the pressure echo light, and the temperature channel detection module 7 is used for receiving and detecting the first temperature photon number and the second temperature photon number in the temperature echo light;

the data processing control module 8 is connected with the first transmitter 1, the second transmitter 2, the third transmitter 3, the water vapor channel detection module 5, the pressure channel detection module 6 and the temperature channel detection module 7, and is used for acquiring data of the water vapor channel detection module 5, the pressure channel detection module 6 and the temperature channel detection module 7 and performing inversion calculation in a unified manner on one hand, and controlling the injection current and the working temperature of the first transmitter 1, the second transmitter 2 and the third transmitter 3 and chopping continuous laser output by the first transmitter 1, the second transmitter 2 and the third transmitter 3 into pulse laser on the other hand;

the data processing control module comprises: the multi-channel data accumulator 8-1 is characterized in that the input end of the multi-channel data accumulator 8-1 is respectively connected with the water vapor channel detection module 5, the pressure channel detection module 6 and the temperature channel detection module 7, the output end of the multi-channel data accumulator 8-1 is connected with the processor 8-2, and the multi-channel data accumulator 8-1 is used for transmitting the water vapor photon number, the pressure photon number, the first temperature photon number and the second temperature photon number to the processor 8-2 to carry out inversion calculation in a unified mode;

the processor 8-2 is also connected with a pulse generator 8-3, and the pulse generator 8-3 is respectively connected with the first transmitter 1, the second transmitter 2 and the third transmitter 3 and provides chopping pulses for the first transmitter 1, the second transmitter 2 and the third transmitter 3;

the processor 8-2 comprises at least one processor connected with the first transmitter 1, the second transmitter 2 and the third transmitter 3 to form a servo unit for adjusting the injection current and the working temperature of the first transmitter 1, the second transmitter 2 and the third transmitter 3.

In specific application, the first transmitter 1 transmits laser with the wavelength of 765nm, the second transmitter 2 transmits laser with the wavelength of 770nm, and the third transmitter 3 transmits laser with the wavelength of 825.5 nm;

the first transmitter 1 comprises 1530.3324nm detection laser seed sources 1-1, 1530.7608nm reference laser seed sources 1-2, a first 1 x 1 switch 1-3, a second 1 x 1 switch 1-4, a first 2 x 1 switch 1-5, a first acousto-optic modulator 1-7, a first erbium-doped optical fiber amplifier 1-9 and a first frequency doubling generator 1-11 which are connected in sequence, the first acousto-optic modulator 1-7 is connected with a first radio frequency oscillator 1-8, and the first radio frequency oscillator 1-8 is connected with a pulse generator 8-3; the first erbium-doped fiber amplifier 1-9 is also connected with a first continuous pumping source 1-10;

the 1530.3324nm detection laser seed source 1-1 comprises a first DFB semiconductor continuous wave wavelength reference hydrogen cyanide unit 1-1-1 and a first DFB semiconductor continuous wave detection wavelength stabilizing unit 1-1-2; the 1530.7608nm reference laser seed source 1-2 comprises a second DFB semiconductor continuous wave wavelength reference hydrogen cyanide unit 1-2-1 and a first DFB semiconductor continuous wave reference wavelength stabilizing unit 1-2-2;

the first DFB semiconductor continuous wave wavelength reference hydrogen cyanide unit 1-1-1 includes: (ii) a

A first distributed feedback laser diode 1-1-1-1 for emitting continuous laser light;

the first coupler 1-1-1-2 is connected with the first distributed feedback laser diode 1-1-1-1 and is used for dividing continuous laser output by the first distributed feedback laser diode 1-1-1 into two parts;

the first electro-optical phase modulator 1-1-1-3 is connected with the first coupler 1-1-1-2, and the first electro-optical phase modulator 1-1-1-3 is used for carrying out phase modulation on laser transmitted from the first coupler 1-1-1-2;

the first hydrogen cyanide gas absorption cell 1-1-1-4 is connected with the first electro-optical phase modulator 1-1-1-3 and is used for enabling the intensity of phase-modulated laser to receive linear absorption of hydrogen cyanide gas molecules R20;

the first InGaAs-PIN detector 1-1-1-5 is connected with the first hydrogen cyanide gas absorption cell 1-1-1-4 and used for detecting the modulated laser passing through the first hydrogen cyanide gas absorption cell 1-1-1-4;

the first transimpedance amplifier 1-1-1-6 is connected with the first InGaAs-PIN detector 1-1-1-5 and is used for amplifying a radio frequency signal output by the first InGaAs-PIN detector 1-1-1-5;

the first power divider 1-1-1-14 is connected with the first modulation radio frequency generator 1-1-1-13 and used for respectively transmitting the modulation signals generated by the first modulation radio frequency generator 1-1-1-13 to the first electro-optical phase modulator 1-1-1-3 and the first phase shifter 1-1-1-15;

the first frequency mixer 1-1-1-7 is respectively connected with the first transimpedance amplifier 1-1-1-6 and the first phase shifter 1-1-1-15 and mixes the radio frequency signal output by the first transimpedance amplifier 1-1-1-6 and the modulation signal output by the first phase shifter 1-1-1-15;

the first low-pass filter 1-1-1-8 is connected with the first mixer 1-1-1-7 and used for performing low-pass filtering on the signals subjected to frequency mixing and outputting analog signals of a feedback loop;

a first analog/digital converter 1-1-1-9 connected to the first low pass filter 1-1-1-8 to convert the analog signal into a digital signal;

the processor 1-1-1-10 is connected with the first analog/digital converter 1-1-1-9 and used for processing the digital signal and calculating to obtain an error digital signal;

the first digital/analog converter 1-1-1-11 is connected with the processor 1-1-1-10 and is used for converting the error digital signal into a corresponding error analog signal;

the first A/D converter 1-1-1-9, the processor 1-1-1-10 and the first D/A converter 1-1-1-11 form a servo unit to play part of the functions of the processor 8-2;

the first current driver and temperature controller 1-1-1-12 is connected with the first digital/analog converter 1-1-1-11 and used for outputting current increment and temperature increment according to the error analog signal;

the first current driver and temperature controller 1-1-1-12 is also connected with the first distributed feedback laser diode 1-1-1 and is used for controlling the injection current and the working temperature of the first distributed feedback laser diode 1-1-1-1;

finally, the working wavelength of the first distributed feedback laser diode 1-1-1-1 is locked on the central wavelength of the hydrogen cyanide gas molecular absorption line R20.

The first DFB semiconductor continuous wave detection wavelength stabilizing unit 1-1-2 includes:

the second distributed feedback laser diode 1-1-2-1 is used for emitting continuous wave laser;

the second coupler 1-1-2-2 is connected with the second distributed feedback laser diode 1-1-2-1, the first 1 x 1 switch 1-3 and the third coupler 1-1-2-3 and is used for respectively sending the laser output by the second distributed feedback laser diode 1-1-2-1 to the first 1 x 1 switch 1-3 and the third coupler 1-1-2-3;

the third coupler 1-1-2-3 is also connected with the first coupler 1-1-1-2 and is used for receiving part of laser of the first distributed feedback laser diode 1-1-1-1 transmitted by the first coupler 1-1-1-2;

the first photoelectric detector assembly 1-1-2-4 is connected with the third coupler 1-1-2-3 and used for heterodyne detection of radio frequency signals of two laser difference frequencies of the third coupler 1-1-2-3;

the first limiting amplifier 1-1-2-5 is connected with the first photoelectric detector assembly 1-1-2-4 and is used for limiting and amplifying radio frequency signals of the first photoelectric detector assembly;

the first frequency divider 1-1-2-6 is connected with the first limiting amplifier 1-1-2-5 and is used for dividing the frequency of the radio-frequency signal subjected to limiting amplification by 32 times;

a first reference clock signal generator 1-1-2-7 for generating a clock signal;

the first direct digital frequency synthesizer 1-1-2-8 is connected with the first reference clock signal generator 1-1-2-7 and is used for generating a reference radio frequency signal of 103.04MHz under the coordination of clock signals;

the first phase-sensitive detector 1-1-2-9 is connected with the first direct digital frequency synthesizer 1-1-2-8 and the first frequency divider 1-1-2-6 and is used for identifying a reference radio frequency signal and an analog signal of the phase difference of the radio frequency signal subjected to frequency division by 32 times;

the second analog/digital converter 1-1-2-10 is connected with the first phase sensitive detector 1-1-2-9 and used for converting the phase difference analog signal into a phase difference digital signal;

the processor 1-1-2-11 is connected with the second analog/digital converter 1-1-2-10 and used for processing the phase difference digital signal to obtain an error digital signal;

the second digital/analog converter 1-1-2-12 is connected with the processor 1-1-2-11 and is used for converting the error digital signal into a corresponding error analog signal;

the second A/D converter 1-1-2-10, the processor 1-1-2-11 and the second D/A converter 1-1-2-12 form a servo unit to play part of the functions of the processor 8-2;

the second current driver and temperature controller 1-1-2-13 is connected with the second digital-to-analog converter and used for outputting current increment and temperature increment according to the error analog signal;

the second current driver and the temperature controller 1-1-2-13 are also connected with the second distributed feedback laser diode 1-1-2-1 and are used for controlling the injection current and the working temperature of the second distributed feedback laser diode 1-1-2-1 and always keeping the working wavelength of the second distributed feedback laser diode 1-1-2-1 to be 25.7pm longer than that of the first distributed feedback laser diode 1-1-1-1;

the final realization locks the operating wavelength of the second distributed feedback laser diode 1-1-2-1 at 1530.3324 nm.

The second DFB semiconductor continuous wave wavelength reference hydrogen cyanide unit 1-2-1 includes:

the third distributed feedback laser diode 1-2-1-1 is used for emitting continuous wave laser;

the fourth coupler 1-2-1-2 is connected with the third distributed feedback laser diode 1-2-1-1 and is used for dividing continuous laser output by the third distributed feedback laser diode 1-2-1-1 into two parts;

the second electro-optical phase modulator 1-2-1-3 is connected with the fourth coupler 1-2-1-2 and is used for carrying out phase modulation on laser transmitted from the second coupler 1-1-2-2;

the second hydrogen cyanide gas absorption cell 1-2-1-4 is connected with the second electro-optical phase modulator 1-2-1-3 and is used for enabling the intensity of the phase-modulated laser to receive the linear absorption of hydrogen cyanide gas molecules R19;

the second InGaAs-PIN detector 1-2-1-5 is connected with the second hydrogen cyanide gas absorption cell 1-2-1-4 and used for detecting laser passing through the second hydrogen cyanide gas absorption cell 1-2-1-4;

the second trans-impedance amplifier 1-2-1-6 is connected with the second InGaAs-PIN detector 1-2-1-5 and is used for amplifying the radio-frequency signal output by the second InGaAs-PIN detector 1-2-1-5;

a second modulated radio frequency generator 1-2-1-13 for generating a modulated signal;

the second power divider 1-2-1-14 is connected with the second modulation radio frequency generator 1-2-1-13, the second electro-optical phase modulator 1-2-1-3 and the second phase shifter 1-2-1-15, and is used for respectively transmitting the modulation signals generated by the second modulation radio frequency generator 1-2-1-13 to the second electro-optical phase modulator 1-2-1-3 and the second phase shifter 1-2-1-15;

the second mixer 1-2-1-7 is connected with the second transimpedance amplifier 1-2-1-6 and the second phase shifter 1-2-1-15, and is used for mixing the radio frequency signal of the second transimpedance amplifier 1-2-1-6 with the modulation signal of the second phase shifter 1-2-1-15;

the second low-pass filter 1-2-1-8 is connected with the second frequency mixer 1-2-1-7 and used for filtering the frequency-converted signals after frequency mixing and outputting analog signals of a feedback loop;

a third A/D converter 1-2-1-9 connected to the second low pass filter 1-2-1-8 for converting the analog signal into a digital signal;

the processor 1-2-1-10 is connected with the third analog/digital converter 1-2-1-9 and used for processing the digital signal and calculating to obtain an error digital signal;

the third digital/analog converter 1-2-1-11 is connected with the processor 1-2-1-10 and is used for converting the error digital signal into a corresponding error analog signal;

the third A/D converter 1-2-1-9, the processor 1-2-1-10 and the third A/D converter 1-2-1-11 form a servo unit to play part of the functions of the processor 8-2;

the third current driver and temperature controller 1-2-1-12 is connected with the third digital-to-analog converter 1-2-1-11 and used for outputting current increment and temperature increment according to the error analog signal;

the third current driver and the temperature controller 1-2-1-12 are also connected with the third distributed feedback laser diode 1-2-1-1 and are used for controlling the injection current and the working temperature of the third distributed feedback laser diode 1-2-1-1;

finally, the working wavelength of the third distributed feedback laser diode 1-2-1-1 is locked at the central wavelength of the hydrogen cyanide gas molecular absorption line R19.

The first DFB semiconductor continuous wave reference wavelength stabilizing unit 1-2-2 includes:

the fourth distributed feedback laser diode 1-2-2-1 is used for emitting continuous wave laser;

the fifth coupler 1-2-2-2 is connected with the fourth distributed feedback laser diode 1-2-2-1, the second 1 × 1 switch 1-4 and the sixth coupler 1-2-2-3 and used for respectively sending the laser output by the fourth distributed feedback laser diode 1-2-2-1 to the second 1 × 1 switch 1-4 and the sixth coupler 1-2-2-3;

the sixth coupler 1-2-2-3 is also connected with the fourth coupler 1-2-1-2 and is used for receiving part of laser light of the third distributed feedback laser diode 1-2-1-1 transmitted by the fourth coupler 1-2-1-2;

the second photoelectric detector assembly 1-2-2-4 is connected with the sixth coupler 1-2-2-3 and is used for heterodyne detection of the radio-frequency signals of the two laser difference frequencies of the sixth coupler 1-2-2-3;

the second limiting amplifier 1-2-2-5 is connected with the second photoelectric detector assembly 1-2-2-4 and is used for limiting and amplifying the radio frequency signal of the second photoelectric detector assembly;

the second frequency divider 1-2-2-6 is connected with the second limiting amplifier 1-2-2-5 and is used for carrying out 32-time frequency division on the radio-frequency signal after limiting amplification;

a second reference clock signal generator 1-2-2-7 for generating a clock signal;

the second direct digital frequency synthesizer 1-2-2-8 is connected with the second reference clock signal generator 1-2-2-7 and used for generating a 101.2MHz reference radio frequency signal under the coordination of the clock signals;

the second phase sensitive detector 1-2-2-9 is connected with the second direct digital frequency synthesizer 1-2-2-8 and the second frequency divider 1-2-2-6 and is used for identifying a phase difference analog signal of a reference radio frequency signal and a radio frequency signal subjected to frequency division by a factor of 32;

the fourth analog/digital converter 1-2-2-10 is connected with the second phase-sensitive detector 1-2-2-9 and used for converting the phase difference analog signal into a phase difference digital signal;

the processor 1-2-2-11 is connected with the fourth analog/digital converter 1-2-2-10 and used for processing the phase difference digital signal and calculating to obtain an error digital signal;

the fourth digital/analog converter 1-2-2-12 is connected with the processor 1-2-2-11 and is used for converting the error digital signal into a corresponding error analog signal;

the fourth A/D converter 1-2-2-10, the processor 1-2-2-11 and the fourth A/D converter 1-2-2-12 form a servo unit to play part of the functions of the processor 8-2;

the fourth current driver and temperature controller 1-2-2-13 is connected with the fourth digital-to-analog converter and used for outputting current increment and temperature increment according to the error analog signal;

the fourth current driver and temperature controller 1-2-2-13 is also connected with the fourth distributed feedback laser diode 1-2-2-1 and is used for controlling the injection current and the working temperature of the fourth distributed feedback laser diode 1-2-2-1 and always keeping the working wavelength of the fourth distributed feedback laser diode 1-2-2-1 to be 25.4pm shorter than that of the third distributed feedback laser diode 1-2-1-1;

finally, the working wavelength of the fourth distributed feedback laser diode 1-2-2-1 is locked at 1530.7608 nm.

The second transmitter 2 comprises 1539.5916nm detection laser seed sources 2-1, 1540.2170nm reference laser seed sources 2-2, a third 1 x 1 switch 2-3, a fourth 1 x 1 switch 2-4, a second 2 x 1 switch 2-5, a second sound optical modulator 2-7, a second erbium-doped fiber amplifier 2-9 and a second frequency multiplier generator 2-11 which are connected in sequence; a second radio frequency oscillator 2-8 is connected to the second acousto-optic modulator 2-7, and the second radio frequency oscillator 2-8 is connected with a pulse generator 8-3; the second erbium-doped fiber amplifier 2-9 is connected with a second continuous pumping source 2-10;

the 1539.5916nm detection laser seed source 2-1 comprises a DFB semiconductor continuous wave wavelength reference acetylene unit 2-1-1 and a second DFB semiconductor continuous wave detection wavelength stabilizing unit 2-1-2; the 1540.2170nm reference laser seed source 2-2 comprises a second DFB semiconductor continuous wave half-wavelength potassium atom KD1 gas cell 2-2-1;

the DFB semiconductor continuous wave wavelength reference acetylene unit 2-1-1 comprises:

a fifth distributed feedback laser diode 2-1-1-1 for emitting continuous wave laser;

the seventh coupler 2-1-1-2 is connected with the fifth distributed feedback laser diode 2-1-1-1 and is used for dividing continuous laser output by the fifth distributed feedback laser diode 2-1-1 into two parts;

the third electro-optical phase modulator 2-1-1-3 is connected with the seventh coupler 2-1-1-2 and is used for carrying out phase modulation on laser transmitted from the seventh coupler 2-1-1-2;

the first acetylene gas absorption cell 2-1-1-4 is connected with the third electro-optic phase modulator 2-1-1-3 and is used for enabling the intensity of the phase-modulated laser to be linearly absorbed by acetylene gas molecules P23;

the third InGaAs-PIN detector 2-1-1-5 is connected with the first acetylene gas absorption pool 2-1-1-4 and used for detecting residual laser after passing through the first acetylene gas absorption pool 2-1-1-4;

the third transimpedance amplifier 2-1-1-6 is connected with the third InGaAs-PIN detector 2-1-1-5 and is used for amplifying the radio frequency signal detected by the first InGaAs-PIN detector 2-1-1-5;

a third modulated radio frequency generator 2-1-1-13 for generating a modulated radio frequency signal;

the third power divider 2-1-1-14 is connected with the third modulation radio frequency generator 2-1-1-13, the third electro-optical phase modulator 2-1-1-3 and the third phase shifter 2-1-1-15, and is used for respectively transmitting the modulation radio frequency signals generated by the third modulation radio frequency generator 2-1-1-13 to the third electro-optical phase modulator 2-1-1-3 and the third phase shifter 2-1-1-15;

a third mixer 2-1-1-7 connected to the third transimpedance amplifier 2-1-1-6 and the third phase shifter 2-1-1-15, for mixing the radio frequency signal amplified by the third transimpedance amplifier 2-1-1-6 with the modulated signal passing through the third phase shifter 2-1-1-15;

the third low-pass filter 2-1-1-8 is connected with the third mixer 2-1-1-7 and is used for filtering the radio-frequency signals subjected to frequency mixing and outputting analog signals of a feedback loop;

a fifth A/D converter 2-1-1-9 connected to the third low pass filter 2-1-1-8 for converting the analog signal into a digital signal;

the processor 2-1-1-10 is connected with the fifth analog/digital converter 2-1-1-9 and used for processing the digital signal and calculating to obtain an error digital signal;

the fifth digital/analog converter 2-1-1-11 is connected with the processor 2-1-1-10 and is used for converting the error digital signal into a corresponding error analog signal;

the fifth A/D converter 2-1-1-9, the processor 2-1-1-10 and the fifth A/D converter 2-1-2-11 form a servo unit to play part of the functions of the processor 8-2;

the fifth current driver and temperature controller 2-1-1-12 is connected with the fifth digital-to-analog converter 2-1-1-11 and used for outputting current increment and temperature increment according to the error analog signal;

the fifth current driver and temperature controller 2-1-1-12 is also connected with the fifth distributed feedback laser diode 2-1-1-1 and is used for controlling the injection current and the working temperature of the fifth distributed feedback laser diode 2-1-1-1;

and finally, the working wavelength of the fifth distributed feedback laser diode 2-1-1-1 is locked at the central wavelength of the absorption line of the acetylene gas molecule P23.

The second DFB semiconductor continuous wave detection wavelength stabilizing unit 2-1-2 includes:

a sixth distributed feedback laser diode 2-1-2-1 for emitting continuous wave laser light;

the eighth coupler 2-1-2-2 is connected with the sixth DFB laser diode 2-1-2-1, the third 1X 1 switch 2-3 and the ninth coupler 2-1-2-3, and is used for sending the laser output by the sixth DFB laser diode 2-1-2-1 to the third 1X 1 switch 2-3 and the ninth coupler 2-1-2-3 respectively;

the ninth coupler 2-1-2-3 is also connected with the seventh coupler 2-1-1-2 and is used for receiving the laser of the fifth distributed feedback laser diode 2-1-1-1 transmitted by the seventh coupler 2-1-1-2;

the third photoelectric detector component 2-1-2-4 is connected with the ninth coupler 2-1-2-3 and is used for heterodyne detection of the radio-frequency signals of the two laser difference frequencies of the ninth coupler 2-1-2-3;

the third limiting amplifier 2-1-2-5 is connected with the third photoelectric detector component 2-1-2-4 and is used for limiting and amplifying the radio frequency signal;

the first reference frequency synthesizer 2-1-2-7 is used for generating an 18GHz ultrahigh frequency signal;

the fourth frequency mixer 2-1-2-6 is connected with the third limiting amplifier 2-1-2-5 and the first reference frequency synthesizer 2-1-2-7 and is used for mixing the radio-frequency signals subjected to limiting amplification with the ultrahigh-frequency signals to obtain down-conversion radio-frequency signals;

the fourth power divider 2-1-2-8 is connected with the fourth mixer 2-1-2-6 and is used for dividing the down-converted radio-frequency signals into two parts, one part of the down-converted radio-frequency signals are directly transmitted to the first radio-frequency power detector 2-1-2-11 to be connected, and the other part of the down-converted radio-frequency signals are filtered by the fourth low-pass filter 2-1-2-9 and then transmitted to the second radio-frequency power detector 2-1-2-10;

the first radio frequency power detector 2-1-2-11 is used for detecting a power numerical value analog signal of the down-converted radio frequency signal; the second radio frequency power detector 2-1-2-10 is used for detecting the analog signal of the radio frequency power passing through the fourth low-pass filter;

the sixth analog/digital converter 2-1-2-12 is respectively connected with the first radio frequency power detector 2-1-2-11 and the second radio frequency power detector 2-1-2-10 and is used for converting the power numerical value analog signal into a power numerical value digital signal;

the processor 2-1-2-13 is connected with the sixth analog/digital converter 2-1-2-12 and used for calculating the ratio of the two power numerical digital signals, obtaining the transmittance of the down-converted radio frequency signal relative to the fourth low-pass filter 2-1-2-9 and calculating according to the power numerical digital signal to obtain an error digital signal;

the sixth digital/analog converter 2-1-2-14 is connected with the processor 2-1-2-13 and is used for converting the error digital signal into a corresponding error analog signal;

the sixth A/D converter 2-1-2-12, the processor 2-1-2-13 and the sixth A/D converter 2-1-2-14 form a servo unit to play part of the functions of the processor 8-2;

the sixth current driver and temperature controller 2-1-2-15 is connected with the sixth digital-to-analog converter and used for outputting current increment and temperature increment according to the error analog signal;

the sixth current driver and temperature controller 2-1-2-15 are also connected with the sixth distributed feedback laser diode 2-1-2-1 and used for controlling the injection current and the working temperature of the sixth distributed feedback laser diode 2-1-2-1 and always keeping the working light frequency of the sixth distributed feedback laser diode 2-1-2-1 20.4GHz more than that of the fifth distributed feedback laser diode 2-1-1-1;

finally, the working wavelength of the sixth distributed feedback laser diode 2-1-2-1 is stabilized at 1539.5916 nm.

The second DFB semiconductor continuous wave reference wavelength stabilizing unit 2-2-1 includes:

a seventh distributed feedback laser diode 2-2-1-1 for emitting continuous wave laser light;

the tenth coupler 2-2-1-3 is connected with the seventh distributed feedback laser diode 2-2-1-1 and the fourth 1 × 1 switch 2-4 and is used for sending the laser output by the seventh distributed feedback laser diode 2-2-1-1 to the fourth 1 × 1 switch 2-4;

a fourth modulated radio frequency generator 2-2-1-15 for generating a modulated radio frequency signal;

the third frequency divider 2-2-1-16 is connected with the fourth modulation radio frequency generator 2-2-1-15 and is used for carrying out double frequency division on the modulation radio frequency signal;

the fourth electro-optical phase modulator 2-2-1-4 is connected with the tenth coupler 2-2-1-3 and the third frequency divider 2-2-1-16 and is used for carrying out phase modulation on the laser output by the tenth coupler 2-2-1-3 according to the modulated radio frequency signal after frequency division;

the third erbium-doped fiber amplifier 2-2-1-5 is connected with the fourth electro-optical phase modulator 2-2-1-4 and is used for amplifying the power of the laser after phase modulation;

the fourth frequency multiplier 2-2-1-6 is connected with the third erbium-doped fiber amplifier 2-2-1-5 and is used for halving the laser wavelength after power amplification;

the second potassium atom gas absorption pool 2-2-1-7 is connected with the fourth frequency doubler 2-2-1-6 and used for enabling the second potassium atom gas absorption pool 2-2-1-7 to absorb part of double frequency continuous wave laser according to linear KD 1;

the first silicon-PIN detector 2-2-1-8 is connected with the second potassium atom gas absorption pool 2-2-1-7 and used for detecting the residual laser after being absorbed by the potassium atom gas to obtain a radio frequency signal;

the fourth phase shifter 2-2-1-17 is connected with the fourth modulation radio frequency generator 2-2-1-15 and is used for performing phase shift on the modulation radio frequency signal generated by the fourth modulation radio frequency generator 2-2-1-15 to obtain a phase-shifted modulation radio frequency signal;

the fifth frequency mixer 2-2-1-9 is connected with the fourth phase shifter 2-2-1-17 and the first silicon-PIN detector 2-2-1-8 and is used for mixing the radio frequency signal output by the silicon-PIN detector with the phase-shifted modulation radio frequency signal;

the fifth low-pass filter 2-2-1-10 is connected with the fifth mixer 2-2-1-9 and used for performing low-pass filtering on the signals obtained by frequency mixing to obtain analog signals;

a seventh analog/digital converter 2-2-1-11 connected to the fifth low pass filter 2-2-1-10 for converting the analog signal into a digital signal;

the processor 2-2-1-12 is connected with the seventh analog/digital converter 2-2-1-11 and used for processing the digital signal and calculating to obtain an error digital signal;

a seventh digital/analog converter 2-2-1-13 connected to the processor 2-2-1-12 for converting the error digital signal into a corresponding error analog signal;

the seventh A/D converter 2-2-1-11, the processor 2-2-1-12 and the third A/D converter 2-2-1-13 form a servo unit to play part of the functions of the processor 8-2;

the seventh current driver and temperature controller 2-2-1-14 is connected with the fifth digital/analog converter 2-1-1-11 and used for outputting current increment and temperature increment according to the error analog signal;

the seventh current driver and temperature controller 2-2-1-14 is also connected with the seventh distributed feedback laser diode 2-2-1-1 and is used for controlling the injection current and the working temperature of the seventh distributed feedback laser diode 2-2-1-1;

finally, the working wavelength of the seventh distributed feedback laser diode 2-2-1-1 is stabilized at the wavelength twice as long as the potassium atomic gas absorption line 770.1085 nm.

The third transmitter 3 comprises 1650.994nm detection laser seed sources 3-1, 1650.666nm reference laser seed sources 3-2, a fifth 1 x 1 switch 3-3, a sixth 1 x 1 switch 3-4, a third 2 x 1 switch 3-5, a first-stage Raman optical fiber amplifier 3-7, a second-stage Raman optical fiber amplifier 3-9 and a third double frequency generator 3-11 which are connected in sequence; a first pulse pump source 3-8 is connected to the first-stage Raman fiber amplifier 3-7, a second pulse pump source 3-10 is connected to the second-stage Raman fiber amplifier 3-9, and the first pulse pump source 3-8 and the second pulse pump source 3-10 are both connected with a pulse generator 8-3;

the 1650.994nm detection laser seed source 3-1 comprises a DFB semiconductor continuous wave wavelength reference methane unit 3-1-1 and a third DFB semiconductor continuous wave detection wavelength stabilizing unit 3-1-2; the 1650.666nm reference laser seed source 3-2 includes only the third DFB semiconductor continuous wave reference wavelength stabilizing cell 3-2-1.

The DFB semiconductor continuous wave wavelength reference methane unit 3-1-1 comprises:

an eighth distributed feedback laser diode 3-1-1-1 for emitting continuous wave laser light;

the eleventh coupler 3-1-1-2 is connected with the eighth DFB laser diode 3-1-1-1 and is used for dividing continuous laser output by the eighth DFB laser diode 3-1-1 into two parts;

the eighth distributed feedback laser diode 3-1-1-1 is connected with the eleventh coupler 3-1-1-2, and the eighth distributed feedback laser diode 3-1-1-1 is used for outputting laser;

the fifth electro-optical phase modulator 3-1-1-3 is connected with the eleventh coupler 3-1-1-2 and is used for carrying out phase modulation on laser transmitted from the eleventh coupler 3-1-1-2;

the first methane gas absorption cell 3-1-1-4 is connected with the fifth electro-optical phase modulator 3-1-1-3 and is used for enabling the laser intensity after phase modulation to be absorbed according to the line shape of an absorption line of methane gas molecules R4;

the fourth InGaAs-PIN detector 3-1-1-5 is connected with the first methane gas absorption pool 3-1-1-4 and is used for detecting laser passing through the first methane gas absorption pool 3-1-1-4;

the fourth transimpedance amplifier 3-1-1-6 is connected with the fourth InGaAs-PIN detector 3-1-1-5 and is used for amplifying an output signal passing through the fourth InGaAs-PIN detector 3-1-1-5;

a fifth modulated radio frequency generator 3-1-1-13 for generating a modulated signal;

the fifth power divider 3-1-1-14 is connected with the fifth modulation radio frequency generator 3-1-1-13, the fifth electro-optical phase modulator 3-1-1-3 and the fifth phase shifter 3-1-1-15, and is used for respectively transmitting the modulation signals generated by the fifth modulation radio frequency generator 3-1-1-13 to the fifth electro-optical phase modulator 3-1-1-3 and the fifth phase shifter 3-1-1-15;

a sixth mixer 3-1-1-7, connected to the fourth transimpedance amplifier 3-1-1-6 and the fifth phase shifter 3-1-1-15, for mixing the radio frequency signal output by the fourth transimpedance amplifier 3-1-1-6 with the modulation signal output by the fifth phase shifter 3-1-1-15;

the sixth low-pass filter 3-1-1-8 is connected with the sixth mixer 3-1-1-7 and is used for filtering the radio-frequency signals subjected to frequency mixing and outputting analog signals of a feedback loop;

the eighth analog/digital converter 3-1-1-9 is connected with the sixth low-pass filter 3-1-1-8 and is used for converting the analog signal output by the sixth low-pass filter 3-1-1-8 into a digital signal;

the processor 3-1-1-10 is connected with the eighth analog/digital converter 3-1-1-9 and used for processing the digital signal and calculating to obtain an error digital signal;

the eighth digital/analog converter 3-1-1-11 is connected with the processor 3-1-1-10 and is used for converting the error digital signal into a corresponding error analog signal;

the eighth A/D converter 3-1-1-9, the processor 3-1-1-10 and the eighth A/D converter 3-1-1-11 form a servo unit to play part of the functions of the processor 8-2;

the eighth current driver and temperature controller 3-1-1-12 is connected with the eighth digital-to-analog converter 3-1-1-11 and used for outputting current increment and temperature increment according to the error analog signal;

the eighth current driver and temperature controller 3-1-1-12 is further connected with the eighth DFB laser diode 3-1-1-1 and is used for controlling the injection current and the working temperature of the eighth DFB laser diode 3-1-1-1;

finally, the working wavelength of the eighth distributed feedback laser diode 3-1-1-1 is locked at the wavelength 1650.958nm of the molecular absorption line R4 of methane gas.

The third DFB semiconductor continuous wave detection wavelength stabilizing unit 3-1-2 includes:

a ninth distributed feedback laser diode 3-1-2-1 for emitting continuous wave laser light;

the twelfth coupler 3-1-2-2 is connected with the ninth DFB laser diode 3-1-2-1, the fifth 1X 1 switch 3-3 and the thirteenth coupler 3-1-2-3 and is used for respectively sending the laser output by the ninth DFB laser diode 3-1-2-1 to the fifth 1X 1 switch 3-3 and the thirteenth coupler 3-1-2-3;

the thirteenth coupler 3-1-2-3 is further connected to the eleventh coupler 3-1-1-2 for receiving the laser light of the eighth dfb laser diode 3-1-1-1 from the eleventh coupler 3-1-1-2;

the fourth photoelectric detector component 3-1-2-4 is connected with the thirteenth coupler 3-1-2-3 and is used for heterodyne detection of the radio-frequency signals of the two laser difference frequencies of the thirteenth coupler 3-1-2-3;

the fourth limiting amplifier 3-1-2-5 is connected with the fourth photoelectric detector component 3-1-2-4 and is used for limiting and amplifying the radio frequency signal;

the fourth frequency divider 3-1-2-6 is connected with the fourth limiting amplifier 3-1-2-5 and is used for carrying out 32-time frequency division on the radio-frequency signal after limiting amplification;

a third reference radio frequency generator 3-1-2-7 for generating a 123.8MHz reference radio frequency signal;

the seventh frequency mixer 3-1-2-8 is connected with the third reference radio frequency generator 3-1-2-7 and the first frequency divider 3-1-2-6 and is used for mixing the reference radio frequency signal and the radio frequency signal subjected to frequency division by 32 times to obtain a down-conversion signal;

the seventh low-pass filter 3-1-2-9 is connected with the seventh mixer 3-1-2-8 and is used for filtering the down-conversion signal to obtain a low-frequency analog signal;

a ninth a/d converter 3-1-2-10 connected to the seventh low pass filter 3-1-2-9 for converting the low frequency analog signal to a low frequency digital signal;

the processor 3-1-2-11 is connected with the ninth analog/digital converter 3-1-2-10 and used for carrying out Fourier transformation on the low-frequency digital signal to obtain the frequency of the low-frequency signal after the seventh low-pass filter 3-1-2-9, and an error digital signal is obtained through calculation according to the frequency;

the ninth digital/analog converter 3-1-2-12 is connected with the processor 3-1-2-11 and is used for converting the error digital signal into a corresponding error analog signal;

the eighth A/D converter 3-1-2-9, the processor 3-1-2-10 and the eighth A/D converter 3-1-2-11 form a servo unit to play part of the functions of the processor 8-2;

a ninth current driver and temperature controller 3-1-2-13 connected to the ninth dac for outputting a current increment and a temperature increment according to the error analog signal;

the ninth current driver and temperature controller 3-1-2-13 is also connected with the ninth distributed feedback laser diode 3-1-2-1 and is used for controlling the injection current and the working temperature of the ninth distributed feedback laser diode and always keeping the working wavelength of the ninth distributed feedback laser diode 3-1-2-1 36pm more than that of the eighth distributed feedback laser diode 3-1-1-1;

finally, the working wavelength of the ninth distributed feedback laser diode 3-1-2-1 is stabilized at 1650.994 nm.

The third DFB semiconductor continuous wave reference wavelength stabilizing unit 3-2-1 includes:

a tenth feedback laser diode 3-2-1-1 for emitting continuous laser;

the tenth feedback laser diode 3-2-1-1 is also connected with a sixth 1 x 1 switch 3-4;

the tenth current driver and the temperature controller 3-2-1-2 are connected with the tenth feedback laser diode 3-2-1-1 and used for controlling the injection current and the working temperature of the tenth feedback laser diode 3-2-1-1; the operating wavelength of the tenth feedback laser diode 3-2-1-1 is passively stabilized at 1650.666 nm.

In this embodiment, the optical path transmission module 4 includes:

a total reflection mirror 4-1 arranged in the transmission direction of the light output from the first transmitter 1 for turning 90 the laser light of the first transmitter 1^°；

The polarization beam combiner 4-2 is arranged at the intersection of the optical path of the second transmitter 2 and the optical path of the total reflection mirror 4-1 and is used for combining the laser of the first transmitter 1 and the laser of the second transmitter 2;

the first dichroic filter 4-3 is arranged at the intersection of the optical path of the third transmitter 3 and the optical path of the polarization beam combiner 4-2 and is used for combining the laser beams of the first transmitter 1, the second transmitter 2 and the third transmitter 3;

4-4 beam expander, 4-5 axial body, 4-6 first lens, 4-8 telescope and 4-9 input/output optical window which are arranged on the transmission optical path of the laser beam combination in sequence; the laser combination beams are sequentially collimated, converted by circular light spots, converged and parallel processed to obtain parallel laser beams containing lasers with wavelengths of 765nm, 770nm and 825.5nm, the parallel laser beams enter atmosphere and are excited to generate atmosphere backscatter echo beams, the backscatter echo beams return to a first lens 4-6 through an input/output optical window 4-9 to be processed in parallel, and then are sequentially processed by a hollow reflector 4-10, a second dichroic filter 4-11 and a small-angle interference filter 4-12;

the second dichroic filters 4 to 11 separate the 825.5nm water vapor echo light in the parallel echo light beam and send the separated water vapor echo light to the water vapor channel detection module 5;

the small-angle interference filter 4-12 separates 765nm pressure echo light in the parallel echo light beams and sends the separated 765nm pressure echo light to the pressure channel detection module 6, and sends 770nm temperature echo light to the temperature channel detection module 7.

The hollow reflector 4-10 is provided with a hollow part and a peripheral reflector, the hollow part is used for enabling the light beam of the circular facula sent by the axial vertebra body 4-5 to pass through without obstruction, and the peripheral reflector is used for enabling the parallel echo light beam to be folded by 90 degrees^°。

In order to accurately detect the number of water vapor photons, the water vapor channel detection module 5 includes:

the first optical filter assembly 5-1 is arranged in the transmission direction of the water vapor echo light and used for inhibiting the ambient light;

a second lens 5-2 disposed in the transmission direction of the light output from the first filter assembly 5-1;

the first single photon counter 5-3 is arranged in the transmission direction of the light output by the second lens 5-2 and is used for detecting the number of water vapor photons in the water vapor echo light;

in order to accurately detect the number of pressure photons, the pressure channel detection module 6 includes:

the second optical filter assembly 6-1 is arranged on the optical path of the pressure echo light and used for inhibiting the ambient light;

a third lens 6-2 arranged in the transmission direction of the light output by the second filter assembly 6-1;

the second single photon counter 6-3 is arranged in the transmission direction of the light output by the third lens 6-2 and is used for detecting the number of pressure photons in the pressure echo light;

in order to accurately detect the first temperature photon count and the second temperature photon count, the temperature channel detection module 7 includes:

a third filter assembly 7-1 disposed on the optical path of the temperature echo light for suppressing ambient light;

70/30 beam splitting sheet 7-2, which is arranged in the transmission direction of the light output by the third optical filter assembly 7-1 and divides the temperature echo light into 30% temperature echo light and 70% temperature echo light;

a fourth lens 7-3 provided in the transmission direction of the 30% temperature echo light;

a third single photon counter 7-4 arranged in the transmission direction of the light output by the fourth lens 7-3 and used for detecting the first temperature photon number in the 30% temperature echo light;

a first potassium atomic gas absorption cell 7-5 provided in the transmission direction of 70% temperature echo light;

a fifth lens 7-6 arranged in the transmission direction of the light output from the first potassium atom gas absorption cell 7-5;

and a fourth single photon counter 7-7 provided in the transmission direction of the light output from the fifth lens 7-6 and detecting the second temperature photon count in the 70% temperature echo light.

Example two:

in this embodiment, the present invention further provides a method for detecting atmospheric moisture, temperature, and pressure by using a micro-pulse laser radar, which specifically includes the steps of:

s1, respectively emitting laser with different wavelengths by using the first transmitter 1, the second transmitter 2 and the third transmitter 3, and synthesizing the laser with different wavelengths into a laser beam;

s11, transmitting laser to the holophote 4-1 by using the first transmitter 1, and turning the laser to the polarization beam combiner 4-2 through the holophote 4-1; wherein, utilizing the first transmitter 1 to emit laser specifically includes: detecting a laser seed source 1-1 at 1530.3324nm and a reference laser seed source 1-2 at 1530.7608nm by using an 1530.3324nm detection laser seed source 1-1 to respectively emit continuous lasers to a first 1 × 1 switch 1-3 and a second 1 × 1 switch 1-4, gating the two continuous lasers to a first acousto-optic modulator 1-7 through the first 2 × 1 switch 1-5, and chopping the continuous lasers into pulse lasers through a first radio frequency oscillator 1-8; after pulse energy is amplified by using the first erbium-doped fiber amplifier 1-9, pulse laser with 765nm is output by a first frequency doubler;

s12, transmitting laser to the polarization beam combiner 4-2 by using the second transmitter 2, perpendicularly intersecting the laser transmitted by the first transmitter 1, and combining the laser into a beam which is folded to the first dichroic filter 4-3; wherein, the emitting laser by the second transmitter 2 specifically includes: using 1539.5916nm detection laser seed source 2-1 and 1540.2170nm reference laser seed source 2-2 to respectively emit continuous laser to a third 1 × 1 switch 2-3 and a fourth 1 × 1 switch 2-4, gating the two continuous lasers to a second sound optical modulator 2-7 through a second 2 × 1 switch 2-5, and chopping the continuous lasers into pulse lasers through a second radio frequency oscillator 2-8; after the pulse capability of the second erbium-doped fiber amplifier 2-9 is amplified, pulse laser of 770nm is output through a second frequency doubler;

s13, transmitting laser to the first dichroic filter 4-3 by using the third transmitter 3, and combining the laser and the laser beam formed by the first transmitter 1 and the second transmitter 2 into one beam; wherein, the emitting laser by the third transmitter 3 specifically includes: using 1650.994nm detection laser seed source 3-1 and 1650.666nm reference laser seed source 3-2 to respectively emit continuous laser to a fifth 1 × 1 switch 3-3 and a sixth 1 × 1 switch 3-4, gating the two continuous lasers to a first Raman optical fiber amplifier through a third 2 × 1 switch 3-5, and chopping the continuous lasers into pulse lasers by using a first pulse pumping source 3-8; after pulse energy is amplified by using a second Raman fiber amplifier, 825.5nm pulse laser is output through a third frequency doubling generator 3-11;

s2, guiding the laser beam to the atmosphere and acquiring an excited atmosphere backscatter echo beam;

s21, collimating the laser beam by using the beam expander 4-4, and converting the laser beam into a circular beam through the axial cone 4-5;

s22, enabling the circular light beam to pass through the hollow part of the hollow reflector 4-10, and converging the circular light beam at the focus of the telescope 4-8 by using a lens;

s23, expanding the beam diameter of the circular beam by multiple times by using a telescope 4-8, and reducing the divergence angle of the circular beam to obtain a parallel beam;

s24, making the parallel light beam enter the atmosphere by using the input/output optical window 4-9, and receiving the atmosphere backscattered echo light beam excited by the parallel light beam by using the input/output optical window 4-9.

S3, converting the back scattering echo light beam into a parallel echo light beam, and separating the parallel echo light beam into vapor echo light, pressure echo light and temperature echo light;

s31, collecting the echo light at the focus of the telescope 4-8 by using the telescope 4-8, and reducing the backscattered echo light beam into a parallel echo light beam by using a lens;

s32, reflecting the parallel echo light beam to a second dichroic filter 4-11 by utilizing the peripheral mirror surface of the hollow reflector 4-10;

s33, separating water vapor echo light from the parallel echo light beams by using a second dichroic filter 4-11, and sending the rest parallel echo light beams to a small-angle interference filter 4-12;

s34, separating the pressure echo light by using the small-angle interference filter 4-12, and obtaining the temperature echo light at the same time.

S4, detecting the water vapor echo light, the pressure echo light and the temperature echo light respectively to obtain a water vapor photon number, a pressure photon number, a first temperature photon number and a second temperature photon number;

s41, receiving water vapor echo light detection through a water vapor channel detection module 5 to obtain a water vapor photon number;

s42, receiving pressure echo light detection through the pressure channel detection module 6 to obtain the number of pressure photons;

and S43, receiving temperature echo light through the temperature channel detection module 7 to detect and obtain a first temperature photon number and a second temperature photon number.

S5, transmitting the water vapor photon number, the pressure photon number, the first temperature photon number and the second temperature photon number to the processor 8-2 for unified inversion calculation to obtain the atmospheric water vapor, the temperature and the pressure.

Example three:

referring to fig. 2, the first transmitter 1 comprises 1530.3324nm probe laser seed source 1-1, 1530.7608nm reference laser seed source 1-2, first 2 × 1 switch 1-5, first optical isolator 1-6, first acousto-optic modulator 1-7 and first rf oscillator 1-8, first erbium-doped fiber amplifier 1-9 and first continuous pump source 1-10, and first frequency doubling generator 1-11. 1530.3324nm detection laser seed source 1-1 and 1530.7608nm reference laser seed source 1-2 with stable wavelength emit continuous laser, which are respectively connected with a first 2 x 1 switch 1-5, gated and respectively connected with a first acousto-optic modulator 1-7 connected with a first radio frequency oscillator 1-8, chopped to have a pulse width within 300ns, the pulse laser with the pulse repetition frequency of 10kHz is amplified by a first erbium-doped fiber amplifier 1-9 comprising a first continuous pumping source 1-10, the pulse energy can reach 80 muJ magnitude, the pulse laser passes through a first frequency doubling generator 1-11, and the wavelength of the frequency-doubled pulse laser is equal to a certain detection wavelength (765.1662nm) of an oxygen A band or equal to a reference wavelength (765.3804nm) of a differential absorption laser radar of the oxygen A band. And finally, 765nm pulse laser pairs with the pulse width of 300ns, the pulse repetition frequency of 10kHz and the pulse energy of 40 mu J are output.

Referring to fig. 2, the second transmitter 2 comprises 1539.5916nm probe laser seed source 2-1, 1540.2170nm reference laser seed source 2-2, second 2 × 1 switch 2-5, second optical isolator 2-6, second acousto-optic modulator 2-7 and second rf oscillator 2-8, second erbium-doped fiber amplifier 2-9 and second continuous pump source 2-10, and second double frequency generator 2-11. 1539.5916nm detection laser seed source 2-1 and 1540.2170nm reference laser seed source 2-2 with stable wavelength emit continuous laser, which are respectively connected with a second 2 x 1 switch 2-5 to gate the two continuous lasers, which are respectively communicated with a second sound optical modulator 2-7 comprising a second radio frequency oscillator 2-8, and chopped into pulse laser with the pulse width within 300ns and the pulse repetition frequency of 10kHz, and the pulse laser is connected with a second erbium-doped fiber amplifier 2-9 of a second continuous pump source 2-10 to amplify the pulse energy, and the pulse energy can reach 110 muJ magnitude; the pulse laser passes through a second frequency doubling generator 2-11, and the wavelength of the pulse laser after frequency doubling is equal to a certain detection wavelength (769.7865nm) of an oxygen A band or equal to a reference wavelength (770.1085nm) of a differential absorption laser radar of the oxygen A band. Finally, 770nm pulse laser pairs with pulse width of 300ns, pulse repetition frequency of 10kHz and pulse energy of 50 muJ are output.

Referring to fig. 2, the third transmitter 3 comprises 1650.994nm probe laser seed source 3-1, 1650.666nm reference laser seed source 3-2, third 2 × 1 switch 3-5, third optical isolator 3-6, first stage Raman fiber amplifier 3-7, second stage Raman fiber amplifier 3-9, first pulse pump source 3-8 of first stage Raman fiber amplifier 3-7, second pulse pump source 3-10 of second stage Raman fiber amplifier 3-9, and third second frequency multiplier generator 3-11. The 1650.994nm detection laser seed source 3-1 and the 1650.666nm reference laser seed source 3-2 with stable wavelengths emit continuous lasers which are respectively connected with a third 2 x 1 switch 3-5 to gate the two continuous lasers, the two continuous lasers are respectively connected with a first-stage Raman optical fiber amplifier 3-7 and chopped into pulse lasers with pulse width within 100ns and pulse repetition frequency of 7kHz, the pulse lasers are amplified by a second Raman optical fiber amplifier 3-9 to obtain pulse energy of 14 mu J magnitude, the pulse lasers are subjected to frequency doubling by a third frequency doubling generator 3-11, and the wavelength of the pulse lasers after frequency doubling is equal to a certain detection wavelength (825.497nm) of a water vapor absorption line or equal to the reference wavelength (825.333nm) of a water vapor differential absorption laser radar. The working substance of the third frequency doubling generator 3-11 is a periodically polarized quasi-phase matching frequency doubling crystal, and the quasi-phase matching crystal is placed in a box which is dry, constant in temperature and transparent at two ends. The conversion efficiency of the frequency doubler can be generally 40-50%. Finally output 825.5nm pulse laser pair, pulse width 100ns, pulse repetition frequency 7kHz, pulse energy 7 muJ.

765nm pulse laser beam emitted by first transmitter 1 passes through 45^°The total reflector 4-1 combines the 770nm pulse laser beam emitted by the second emitter 2 into one beam through the polarization beam combiner 4-2, then combines the 825.5nm pulse laser beam emitted by the bicolor 4-3 and the third emitter 3 into a beam, and is collimated into parallel light by the beam expander 4-4, the cross section of the parallel light beam is a circular light spot, and the parallel light beam is deformed into a truncated light beam through the pair of conical prisms 4-5A parallel light beam with a circular surface, which passes through 45^°Then converged by the lens 4-6 at the focal point 4-7 of the telescope 4-8.

The pulse laser from the focus 4-7 enters the telescope 4-8, the light beam expands into parallel light beams with smaller divergence angles, the secondary mirror of the telescope 4-8 does not bring light beam loss because of blocking the parallel light beams, and the parallel light beams from the telescope 4-8 pass through the input/output light window 4-9 to enter the atmosphere.

The echo beam backscattered by the atmosphere of the lower troposphere passes through the input/output optical window 4-9 again, is collected by the telescope 4-8 and converged at the focal point 4-7, the beam from the focal point 4-7 is reduced by the lens 4-6 into a parallel beam, the diameter of the parallel echo beam is larger than that of the emitted beam, so that the echo beam is reflected by the lens 45^°After the peripheral mirror surface of the hollow reflector 4-10 is reflected, the light beam direction is deflected by 90^°The echo parallel light is divided into two branches by the bicolor 4-11, one branch of 825.5nm water vapor echo light enters the water vapor channel detection module 5, and the rest branch of the water vapor echo light passes through the bicolor 4-11 and passes through the incident angle smaller than 22.5^°The interference filter 4-12 is divided into two paths, one path of 770nm temperature echo light passes through the small-angle interference filter 4-12 and enters the temperature channel detection module 7, and the other path of 765nm pressure echo light is totally reflected by the small-angle interference filter 4-12 and enters the pressure channel detection module 6.

Referring to fig. 2, 825.5nm water vapor echo light passes through a first optical filter assembly 5-1 to inhibit ambient light, passes through a second lens 5-2 and is detected by a first Single Photon Counting Module (SPCM)5-3, and detected photon data is received by an input end of a multi-channel accumulator 8-1; in fig. 7, the first filter combination 5-1 includes a 12nm broadband filter 5-1-1, an etalon 5-1-2, and a 750pm dual cavity narrowband filter 5-1-3, and the free spectral range of the etalon 5-1-2 is designed such that 825.497nm and 825.333nm are two adjacent modes of the etalon 5-1-2, and both pass through the etalon 5-1-2. The spectral curve of the dual-cavity narrowband filter 5-1-3 is flat-topped and has comparable transmittances at 825.497nm and 825.333 nm.

Referring to fig. 2, 765nm pressure echo light passes through a second optical filter assembly 6-1 and a third lens 6-2, is detected by a second single-photon counter 6-3, and the detection result is sent to a multi-channel accumulator 8-1. In fig. 7, the second filter combination 6-1 comprises a 12nm broadband filter 6-1-1, an etalon 6-1-2, and a 750pm dual cavity narrowband filter 6-1-3, and the free spectral range of the etalon 6-1-2 is designed such that 765.1662nm and 765.3804nm are two adjacent modes of the etalon 6-1-2, and both can pass through the etalon 6-1-2. The free spectral range of the etalon 6-1-2 is equal to the difference between the online and offline wavelengths.

Referring to fig. 2, 770nm temperature echo light is split into two paths by the 70/30 beam splitter 7-2, 30% of 770nm temperature echo light passes through the fourth lens 7-3 and is detected by the third single photon counter 7-4, the detected data is received by the input end of the multichannel accumulator 8-1, 70% of 770nm temperature echo light passes through the first potassium atomic gas absorption cell 7-5, the echo light passing through the first potassium atomic gas absorption cell 7-5 passes through the fifth lens 7-6 and is detected by the fourth single photon counter 7-7, and the detection result is sent to the multichannel accumulator 8-1. In fig. 7, the third filter combination 7-1 comprises a 12nm broadband filter 7-1-1, an etalon 7-1-2, and a 750pm dual cavity narrowband filter 7-1-3, the free spectral range of the etalon 7-1-2 being designed such that 769.7958nm and 770.1085nm are two adjacent modes of the etalon 7-1-2, both of which can pass through the etalon 7-1-2. The second transmitter of the laser radar is added with the temperature channel detection module 7, the processor 8-2 and the pulse generator 8-3 are added to form a 769.7958nm/770.1085nm differential absorption laser radar, a 770.1085nm high-spectral-resolution laser radar is added, the Mie backscattering spectral width of the echo of the laser radar is much smaller than that of the Rayleigh backscattering spectral width, the first potassium atom gas absorption pool 7-5 is the Mie-Rayleigh spectral analyzer of the high-spectral-resolution laser radar, 30% of the channels are Mie-Rayleigh channels, namely the photon number N detected by 30% of the channels₃₀Both Mie and Rayleigh backscattering components; while 70% of the channels are Rayleigh channels, 70% of the photons detected N₇₀There should be no Mie backscattering component in the middle. The following equation can be expressed:

expressed in a matrix:

solution of the equation:

wherein S is_aAll signals, S, representing Mie backscatter in 30% echo_mAll signals representing Rayleigh backscattering in 30% echoes; wherein A is_a、A_m、B_mAll are coefficients of the laser radar system, and the values can be obtained through calibration, so that S is solved_aAnd S_mThen, the backscattering ratio of the 770.1085nm laser light to the atmosphere is known:

(β_m+β_a)/β_m＝(S_a+S_m)/S_m (4)

since the wavelength of 769.7958nm is very close to the wavelength of 770.1085nm, it is believed that the backscattering ratio of 769.7958nm is equal to the backscattering ratio of 770.1085 nm. The backward scattering ratio of 769.7958nm is important for solving the absorption coefficient alpha of oxygen to 769.7958nm laser, and the absorption coefficient alpha appears in a formula of temperature iterative operation.

Referring to fig. 6, a first pulse pump source 3-8 of a first Raman fiber amplifier 3-7 comprises an erbium-doped fiber amplifier 3-8-3, an SOA semiconductor optical amplifier 3-8-2, a swept DBR laser diode 3-8-1, and a scan current driver 3-8-4 of the DBR laser diode 3-8-1; the output current of the current driver 3-8-4 rises and falls in a triangular shape, the laser of the DBR laser diode 3-8-1 is driven to sweep frequency continuously, the pulse width of the drive current is less than 200ns, the laser pulse of the DBR laser diode 3-8-1 changes optical frequency at 1480nm or 980nm, the semiconductor optical amplifier 3-8-2 amplifies the 1480nm or 980nm pulse laser, the semiconductor optical amplifier 3-8-2 outputs 1.55 mu m pulse laser through the pump erbium-doped optical fiber amplifier 3-8-3, the 1.55 mu m pulse laser excites the first Raman optical fiber amplifier 3-7, and under the condition of 1651nm continuous laser seed injection, 1651nm laser of pulse is emitted.

Referring to fig. 6, the second pulsed pump source 3-10 of the second Raman fiber amplifier 3-9, like the above, is not further described. Through a two-stage Raman fiber amplifier, single-frequency laser with the time width of 100ns, the repetition frequency of 7kHz and the pulse energy of 14 mu J can be obtained.

(1) In the inversion process of the water vapor content, the most important relational formula is as follows:

wherein n is_wvIs the molecular density of atmospheric water vapor, Δ r is the distance resolution unit, σ is the absorption cross section of the water vapor online wavelength and offline wavelength (subscripts on and off, respectively), and N is the number of online wavelength and offline wavelength water vapor photons (subscripts on and off, respectively) received by the water vapor channel detection module 5, σ is a function of atmospheric temperature and pressure at height r. Thus, there is a precondition for obtaining a vertical profile of the water vapor content: the vertical distribution of atmospheric temperature and pressure is entered as a condition into the inversion program.

(2) The iterative formula of the atmospheric temperature inversion is as follows:

whereinThat is the mixing ratio of oxygen in the atmosphere,the mixing ratio of water vapor in the atmosphere, and P is the atmospheric pressure; t is_i+1(z) and T_i(z) a sequence of iterative calculations of the atmospheric temperature at a certain altitude; it can be seen that to perform iterative calculation on the atmospheric temperature, the mixing ratio of water vapor in the atmosphere and the atmospheric pressure are both calculation conditions which need to be input. k is a radical of_BBoltzmann constant, T₀Normal temperature, S₀The peak value of the absorption coefficient, the line form of the lambda absorption line, epsilon represents the energy level, h Planck constant and c is the speed of light.

(3) The atmospheric pressure corresponds to the differential optical thickness of the two wavelengths of the a-band as follows:

whereinThat is, the mixing ratio of water vapor at the z-height of the atmosphere, n (z) is the molecular density of the atmosphere at the z-height,andis the absorption cross section (subscripts on and off, respectively) of the oxygen molecule a at height z with an online wavelength and an offline wavelength, as a function of the temperature of the atmosphere at z; therefore, to calculate the atmospheric pressure, the optical thickness dz is calculated, which in turn requires a priori values of the atmospheric temperature and the water-vapor mixture ratio.

From the above, the vertical profiles of the atmospheric temperature, the water vapor and the pressure are coupled with each other, so that when a certain parameter is inverted, the numerical values of the other two parameters can be used as input conditions, and iteration converges; this is an advantage of the composite detection of three parameters.

(4)1540.2170nm pulse laser passes through a second frequency doubler 2-11 with quasi-phase matching, half of the energy is converted into 770.1085nm pulse laser, and the rest half of the energy is 1540.2170nm pulse laser, and the 50 muj, 10kHz, 300ns pulsed laser is launched into the atmosphere, its backscattered echo, the signal is compared with 1540.2170nm local oscillation laser of continuous wave (1% of power is separated from the second erbium-doped fiber amplifier 2-9 to be used as a local oscillation), a radio frequency signal after heterodyne detection, the signal from the second rf oscillator 2-8 of the second acousto-optic modulator 2-7 is mixed and low-pass filtered again, after which the signal is a-D converted and Fast Fourier Transformed (FFT), applying the doppler principle, information on the wind speed can be obtained, if the emitting direction of 1540.2170nm pulse laser can be rotated, the wind vector can be reversed.

The key core devices (DFB/DBR laser diode, erbium-doped fiber amplifier, acousto-optic modulator, electro-optic modulator and single photon counting module SPCM) used by the troposphere atmospheric water vapor temperature pressure micro-pulse laser radar under composite detection are mature devices in the field of micro-light detection in the optical communication industry, the cost of the micro-pulse laser radar for compositely detecting the troposphere atmospheric water vapor temperature pressure can be obviously reduced, the reliability and the safety are improved, the popularization and the use are convenient, the earth surface is arranged in a network mode, the micro-pulse laser radar becomes a model for comprehensively using the Internet of things technology, the artificial intelligence technology and the big data technology in the near future, and further, the means for manually releasing the radio sounding balloon to measure the meteorological parameter vertical profile becomes history.

In the description, various embodiments are described in a progressive mode, each embodiment focuses on differences from other embodiments, and the same and similar parts among the various embodiments are referred to each other. The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In summary, this summary should not be construed to limit the present invention.