阅读说明：本技术 一种获取高帧频光谱的装置 (Device for acquiring high frame frequency spectrum ) 是由 张军英 白亚亚 高明 刘光海 张雄星 陈海滨 王伟 郭子龙 于 2020-12-31 设计创作，主要内容包括：本发明涉及一种获取高帧频光谱的装置,包括宽带光源、光纤环行器、光纤传感器连接端口、1×N光纤分束器、光谱仪模组、采样电路和信号同步及控制电路。宽带光源与光纤环行器的A端口相连,光纤环行器的B端口与光纤传感器连接端口相连,光纤环行器的C端口与1×N光纤分束器相连,光纤分束器之后依次为光谱仪模组、采样电路和信号同步及控制电路。本发明通过一种错时采样技术,将光谱仪模组中并连的N个光谱仪模块采集得到的光谱数据在后端拼合后实现高速采样,获取到高速采样光谱数据。(The invention relates to a device for acquiring a high frame frequency spectrum, which comprises a broadband light source, an optical fiber circulator, an optical fiber sensor connecting port, a 1 xN optical fiber beam splitter, a spectrometer module, a sampling circuit and a signal synchronization and control circuit. The broadband light source is connected with the port A of the optical fiber circulator, the port B of the optical fiber circulator is connected with the connecting port of the optical fiber sensor, the port C of the optical fiber circulator is connected with the 1 XN optical fiber beam splitter, and the spectrometer module, the sampling circuit and the signal synchronization and control circuit are sequentially arranged behind the optical fiber beam splitter. According to the invention, by a time-staggered sampling technology, high-speed sampling is realized after spectrum data acquired by N spectrometer modules connected in parallel in a spectrometer module are spliced at the rear end, and high-speed sampling spectrum data is acquired.)

1. The utility model provides an acquire device of high frame frequency spectrum, includes broadband light source (1), optic fibre circulator (2), optical fiber sensor connection port (3), 1 XN optic fibre beam splitter (4), spectrum appearance module (5), sampling circuit (6) and signal synchronization and control circuit (7), its characterized in that: the broadband light source (1) is connected with an A port of the optical fiber circulator (2), a B port of the optical fiber circulator (2) is connected with an optical fiber sensor connecting port (3), a C port of the optical fiber circulator (2) is connected with a 1 xN optical fiber beam splitter (4), and a spectrometer module (5), a sampling circuit (6) and a signal synchronization and control circuit (7) are arranged behind the 1 xN optical fiber beam splitter (4) in sequence; the spectrometer module (5) is formed by connecting N spectrometer modules in parallel after being respectively connected with the 1 XN optical fiber beam splitter (4).

2. The apparatus for acquiring high frame rate spectra according to claim 1, wherein the spectrometer module (5) employs a time-division exposure and spectral output splicing algorithm, wherein the time-division exposure and spectral output splicing algorithm is performed by a signal synchronization and control circuit.

The technical field is as follows:

the invention relates to the technical field of optical fiber sensing, in particular to a device for acquiring a high-frame frequency spectrum.

Background art:

compared with the traditional electrical sensor, the optical fiber sensor has the advantages of small loss, insensitivity to external electromagnetic field, remote measurement and the like, and the optical fiber Fabry-Perot sensor and the optical fiber grating sensor are widely applied to the detection fields of pressure, temperature, strain, acceleration, high-precision micro displacement, chemical substances and the like.

At present, for practical application of various sensors, especially when measuring high-speed dynamic variation, such as testing of dynamic pressure of an aircraft engine, how to realize high-speed sampling to achieve high-speed demodulation is the key point of the practical application.

The spectrum method is one of the most important methods for demodulating an optical fiber sensing system, and the basic principle of the method is that a light source emits broadband light to enter an optical fiber sensing device, a spectrum analyzer module is used for collecting a reflection spectrum of the optical fiber sensing device, the obtained reflection spectrum is analyzed, corresponding cavity length information is demodulated, and therefore external physical quantity is determined through a calibration relation. The advantages of the spectrum method are: the demodulation precision is high, the cavity length demodulation range is large, and the absolute cavity length demodulation can be realized.

At present, a spectrometer module is mostly adopted in a spectrum method to sample spectrum data of an optical fiber sensing device. The spectrometer module adopted by the spectrum demodulation technology is generally composed of a light beam shaping element, an optical dispersion element and a linear array photoelectric detector, the spectrum acquisition rate, namely the frame frequency of the spectrometer is generally low and generally within 10kHz, the requirements of high-speed demodulation of an optical fiber sensor device under the application scenes of aeroengine dynamic pressure test, ultrasonic or shock wave detection and the like cannot be met, and the bottleneck that the spectrum acquisition rate of the spectrometer module is too low is urgently needed to be solved.

The invention content is as follows:

the invention provides a device for acquiring high frame frequency spectrum, which aims at the technical bottleneck of the conventional spectrum method for demodulating the spectrum acquisition rate of an optical fiber sensing device.

In order to solve the problems in the prior art, the technical scheme of the invention is as follows: the utility model provides an acquire device of high frame frequency spectrum, includes broadband light source, optical fiber circulator, optical fiber sensor connection port, 1 XN optic fibre beam splitter, spectrum appearance module, sampling circuit and signal synchronization and control circuit, its characterized in that: the broadband light source is connected with the port A of the optical fiber circulator, the port B of the optical fiber circulator is connected with the connecting port of the optical fiber sensor, the port C of the optical fiber circulator is connected with the 1 XN optical fiber beam splitter, and the spectrometer module, the sampling circuit and the signal synchronization and control circuit are sequentially arranged behind the optical fiber beam splitter; the spectrometer module is formed by connecting N spectrometer modules in parallel after being respectively connected with a 1 XN optical fiber beam splitter.

Further, the spectrometer module adopts a time-staggered exposure and spectrum output splicing algorithm, wherein the time-staggered exposure and spectrum output splicing algorithm is completed by a signal synchronization and control circuit.

Compared with the prior art, the invention has the following advantages:

the high-speed spectrometer module provided by the invention is formed by respectively connecting N spectrometer modules to a 1 XN beam splitter and then connecting the N spectrometer modules in parallel, and N sampling circuits are connected behind the N spectrometers. In the proposed time-sharing exposure and signal synchronization technology, a signal synchronization and control circuit generates N paths of pulse signals with the phase difference of 360 DEG/N, the N paths of pulse signals with the phase difference of 360 DEG/N are connected to control ends of N spectrometers, the high level time of the pulse signals is the integration time of the spectrometers, the interval of the two pulse signals is the sampling interval of the spectrometers, the time delay of a single pulse signal is set to be 1/N of the sampling interval, namely the sampling interval of a spectrometer module is 1/N of the sampling interval of the single spectrometer, namely the frame frequency of the spectrometer module is increased to be N times of the single spectrometer, so that the time-sharing exposure of the N spectrometers is realized. The frame frequency of the spectrometer module is increased to be N times of that of a single spectrometer, so that the limitation of the scanning speed of the spectrometer is broken through, high-frame-frequency spectrum acquisition is realized, and the problem of low sampling speed of the single spectrometer module is solved.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of the present invention;

FIG. 2 is a timing diagram of a spectrometer module in an embodiment of the invention;

FIG. 3 is a diagram illustrating 4 RST signals with 90 ° phase difference according to an embodiment of the present invention;

description of the labeling: the device comprises a 1-broadband light source, a 2-optical fiber circulator, a 3-optical fiber sensor connecting port, a 4-1 XN optical fiber beam splitter, a 5-high-speed spectrometer module, a 6-sampling circuit and a 7-signal synchronization and control circuit.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The principle sketch of the system is shown in fig. 1, the broadband light emitted by an SLD broadband light source 1 in the system reaches an optical fiber sensor connecting port 3 through an optical fiber circulator 2, when the optical fiber sensor connecting port is connected with a reflection type optical fiber sensor, reflected light of the sensor is coupled into the optical fiber sensor connecting port 3, then is emitted out through a C port of the optical fiber circulator and is connected to a 1 xN optical fiber beam splitter 4, a spectrometer module 5 is connected behind the optical fiber beam splitter, and the spectrometer module converts optical signals into electric signals which are processed by a sampling circuit 6 and a signal synchronization and control circuit 7.

In this embodiment, the optical fiber beam splitter adopts 1 × 4, 4 spectrometer modules are connected behind the optical fiber beam splitter to form a spectrometer module, a time-sharing exposure and spectrum output splicing algorithm is adopted to sample the reflection spectrum of the fabry-perot cavity optical fiber sensor, the used spectrometer is an I-MON miniature optical fiber spectrometer module of beijing bowey technologies ltd, fig. 2 is a timing diagram of the spectrometer module, a RESET signal in the timing diagram is a RST signal for controlling current integration, at least 6 clocks need to be continued according to an outgoing test list of the spectrometer module, the signal keeps occupying 28 fixed clocks, 256 pixels are shifted and output to occupy 256 clocks, and the spectrometer module performs primary spectrum acquisition and at least 290 clock cycles need to be occupied. The frequency of the clock CLK is set to 10MHz, the highest frame rate of a single spectrometer is:

so 4 spectrometer modules can constitute a high-speed spectrometer module with a frame frequency of over 100 kHz.

The key problem of high frame frequency spectrum acquisition is the time-sharing exposure and data synchronization of the spectrometer, which must be tightly combined with the sensing, conversion, control and output interfaces of the bottom layer of the spectrometer. In the embodiment, the sensing of the spectrometer module is a photodiode linear array, and the photoelectric conversion circuit is a current integration circuit.

The current integration circuit has the advantage that the sensitivity of photoelectric conversion can be changed by changing the current integration time, so that the current integration circuit is suitable for spectral measurement of optical signals with different light intensities. The current integration time is controlled by the RST signal, and on the rising edge of the RST signal, a switch of the current integration is conducted, and the photocurrent starts to charge the integration capacitor; at the falling edge of the RST signal, the switch for current integration is turned off, the voltage of the integration capacitor remains unchanged, and a shift output is awaited.

The current integration is determined by the RST pulse, and the process of current integration is the process of spectrometer exposure. The high level time of the RST pulse corresponds to the exposure time of the spectrometer, the position and the duration of the high level of the RST pulse determine the exposure time and the exposure duration of the spectrometer, and the interval of the RST pulse determines the sampling interval of the spectrometer. Namely, the key of the time-sharing exposure of the spectrometer is the accurate phase shift of the RST pulse signals of a plurality of spectrometers.

In this embodiment, 4 spectrometer modules are connected in parallel, a signal synchronization and control circuit generates 4 RST signals with a phase difference of 90 °, the RST signal is connected to RST control ends of the 4 spectrometers, so that time-sharing exposure of the 4 spectrometers can be realized, a timing diagram is shown in fig. 3, a delay time of the 4 RST signals is equal to one fourth of a sampling interval, that is, the sampling interval of a spectrometer module is one fourth of the sampling interval of a single spectrometer, and thus, a frame frequency of the spectrometer module is increased to 4 times of that of the single spectrometer.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and it should be noted that those skilled in the art should make modifications and variations without departing from the principle of the present invention.