Radio frequency phase coding signal generation device and method based on microwave photon technology
阅读说明：本技术 基于微波光子技术的射频相位编码信号产生装置及方法 (Radio frequency phase coding signal generation device and method based on microwave photon technology ) 是由 于文琦 刘建国 杨成悟 李金野 于 2018-08-09 设计创作，主要内容包括：本发明公开了一种基于微波光子技术的射频相位编码信号产生装置及方法。其中，该装置包括：光源、可变单边带调制模块、相位调制模块、二进制码发生模块、微波驱动模块和光电收发模块，光源发出的光被分束器分成两路，其中一路送给可变单边带调制模块得到单边带调制的光信号，另一路送给相位调制模块，得到相位调制的光信号；单边带调制模块和相位调制模块的驱动信号由微波驱动模块提供，两路已调制的光信号经合束器合成一路，再送给光电收发模块，最后输出射频相位编码信号。本发明所提供的基于微波光子技术的射频相位编码信号产生装置及方法具有结构简单、动态范围大、可调谐等优点，可以产生载频可调谐、大带宽的射频相位编码信号。(The invention discloses a device and a method for generating a radio frequency phase coding signal based on a microwave photon technology. Wherein, the device includes: the system comprises a light source, a variable single-sideband modulation module, a phase modulation module, a binary code generation module, a microwave driving module and a photoelectric transceiving module, wherein light emitted by the light source is divided into two paths by a beam splitter, one path of light is sent to the variable single-sideband modulation module to obtain a single-sideband modulated optical signal, and the other path of light is sent to the phase modulation module to obtain a phase modulated optical signal; the driving signals of the single-side band modulation module and the phase modulation module are provided by the microwave driving module, the two paths of modulated optical signals are combined into one path through the beam combiner, then the path is sent to the photoelectric transceiving module, and finally the radio frequency phase coding signal is output. The device and the method for generating the radio frequency phase coding signal based on the microwave photon technology have the advantages of simple structure, large dynamic range, tunability and the like, and can generate the radio frequency phase coding signal with tunable carrier frequency and large bandwidth.)
1. An apparatus for generating a radio frequency phase encoded signal based on microwave photonic technology, the apparatus comprising: light source, variable single sideband modulation module, phase modulation module, binary code generation module, microwave drive module and photoelectricity receiving and dispatching module, wherein:
the light source, the variable single-side band modulation module, the phase modulation module and the photoelectric transceiving module are connected through optical fibers, the light source, the variable single-side band modulation module and the photoelectric transceiving module are connected into one path, and the light source, the phase modulation module and the photoelectric transceiving module are connected into the other path;
the light emitted by the light source is divided into two paths by the beam splitter, wherein one path of light is sent to the variable single-sideband modulation module, and the light is driven by an output signal of the microwave driving module to generate a single-sideband modulated light signal, wherein the light signal comprises a carrier and a + 1-order sideband or the carrier and a-1-order sideband; the other path is sent to a phase modulation module, an output signal of the microwave driving module drives the phase modulation optical signal to be generated, the two paths of modulated optical signals are combined into one path through a beam combiner, then sent to a photoelectric transceiving module, and finally a radio frequency phase coding signal is output;
the output signal of the microwave driving module drives and controls the variable single-sideband modulation module and the phase modulation module to generate corresponding optical signals;
the binary code generation module outputs '0' or '1' to determine an output signal of the microwave driving module, and further controls the variable single-sideband modulation module to output a +1 order sideband single-sideband modulation signal or a-1 order sideband modulation signal.
2. The microwave photonic technology-based radio frequency phase encoded signal generating apparatus of claim 1, wherein the light source is a monochromatic laser light source comprising a semiconductor laser, a solid state laser or a fiber laser.
3. The microwave photonic technology-based radio frequency phase encoded signal generating apparatus of claim 1, wherein: the variable single sideband modulation module is a dual-drive Mach-Zehnder modulator or a dual-parallel Mach-Zehnder modulator and works in a single sideband modulation state.
4. The microwave photonic technology-based radio frequency phase encoded signal generating apparatus of claim 1, wherein: the phase modulation module is a phase modulator, and generates a double-sideband modulation signal under the drive of an output signal of the microwave drive module, wherein the phase difference of +/-1 order sidebands is pi.
5. The microwave photonic technology-based radio frequency phase encoded signal generating apparatus of claim 1, wherein: the binary code generation module generates high or low levels representing "1" and "0".
6. The microwave photonic technology-based radio frequency phase encoded signal generating apparatus of claim 1, wherein: the microwave driving module comprises two adjustable direct current voltage sources, a binary code driving module, an adjustable microwave source, a power divider and a 90-degree phase shifter, the two adjustable direct current voltage sources respectively control direct current bias of the phase modulation module and direct current bias of the variable single-sideband modulation module, the binary code driving module realizes that the variable single-sideband modulation module outputs carrier waves and-1-order sidebands or the carrier waves and + 1-order sidebands by setting a high level value or a low level value, and the adjustable microwave source combines the power divider and the 90-degree phase shifter to provide modulation signals for the phase modulation module and the variable single-sideband modulation module.
7. The microwave photonic technology-based radio frequency phase encoded signal generating apparatus of claim 1, wherein: the photoelectric transceiving module comprises a beam combiner, a photoelectric detector and a radio frequency amplifier, wherein the beam combiner converts two paths of modulated optical signals into electric signals after combining the electric signals, and the electric signals are amplified by the radio frequency amplifier and then radio frequency phase coded signals are output.
8. A method for generating a radio frequency phase-coded signal based on microwave photonic technology, wherein the device of claims 1-7 is used for generating the radio frequency phase-coded signal, and the method comprises the following steps:
predefining a binary code sequence in a binary code generation module;
turning on a light source;
adjusting two direct current voltages of the microwave driving module to enable the phase difference pi or-pi between the direct current bias of the phase modulation module and the direct current bias of the variable single-sideband modulation module;
setting the output frequency and power of an adjustable microwave source of a microwave driving module;
setting the high and low level values of the binary code driving module, wherein the difference between the phase corresponding to the two level states and the phase corresponding to the DC bias of the variable single-sideband modulation module is required to be respectively
Setting the radio frequency gain of the photoelectric transceiving module;
and starting the binary code generation module and the photoelectric transceiving module to obtain a predefined radio frequency phase coding signal.
Technical Field
The invention belongs to the field of radars, microwave photon technology, electronic communication and the like, and particularly relates to a device and a method for generating a radio frequency phase coding signal based on the microwave photon technology.
Background
Microwave pulse compression is widely used in modern radar systems to increase range accuracy. The phase coding signal is a commonly used radar pulse compression signal, has good pulse compression capacity, can effectively improve the resolution of a radar system, and solves the contradiction between the action distance and the resolution capacity. Therefore, the generation of the phase coding signal is an important research direction in related fields such as radar and the like, and has very important practical significance and utilization value. Although phase encoded signals can be implemented in the electrical domain, they are limited by the speed of current digital circuits such that the operating frequency and time-bandwidth product are small. The working frequency of modern radar systems is continuously developing towards higher frequency bands, and the traditional method for generating phase coding signals by using electronic technology cannot meet the practical application requirements.
Due to the wide-band, large tunability, and anti-electromagnetic interference properties of photonic technology, many methods have been proposed in the optical domain to produce phase encoded signals with high frequency and large time-bandwidth products. There are many methods that have been proposed to generate phase encoded signals using microwave photonic technology. The phase encoded signal may be generated using a Sagnac interferometer and a phase modulator. A disadvantage of this approach is that the high sensitivity of the interferometer to ambient and temperature introduces severe phase perturbations. It has also been proposed to generate phase encoded signals based on a four tap delay line microwave photonic filter. By carefully adjusting the delay of each tap, different phases can be introduced into the microwave pulse. The compression ratio of the phase encoded signal produced in this manner is limited by the number of taps of the filter. It has also been proposed to use two polarization modulators and an optical bandpass filter to generate the phase encoded signal, but this approach requires the use of an optical bandpass filter, which increases the cost and complexity of the system.
Although microwave photonic technology is considered to be an effective way to solve the bandwidth problem faced by the current electronic technology, the common problems of the current phase-coded signal generation system based on the microwave photonic technology are that the system is complex, has poor stability and is not high enough in precision.
Disclosure of Invention
Technical problem to be solved
It is therefore an object of the present invention to provide an apparatus and a method for generating an rf phase-encoded signal based on microwave photonic technology, so as to at least partially solve the above technical problems.
(II) technical scheme
The technical scheme of the invention is as follows:
an apparatus for generating a radio frequency phase-encoded signal based on microwave photonic technology, the apparatus comprising: light source, variable single sideband modulation module, phase modulation module, binary code generation module, microwave drive module and photoelectricity receiving and dispatching module, wherein:
the light source, the variable single-side band modulation module, the phase modulation module and the photoelectric transceiving module are connected through optical fibers, the light source, the variable single-side band modulation module and the photoelectric transceiving module are connected into one path, and the light source, the phase modulation module and the photoelectric transceiving module are connected into the other path;
light emitted by a light source is divided into two paths by a beam splitter, wherein one path is sent to a variable single-sideband modulation module, an output signal of a microwave driving module is used for driving to generate a single-sideband modulated optical signal, the optical signal comprises a carrier and a +1 order sideband or the carrier and a-1 order sideband, the other path is sent to a phase modulation module, an output signal of the microwave driving module is used for driving to generate a phase modulated optical signal, the two paths of modulated optical signals are combined into one path by a beam combiner and then sent to a photoelectric transceiving module, and finally a radio frequency phase coding signal is output;
the output signal of the microwave driving module drives and controls the variable single-sideband modulation module and the phase modulation module to generate corresponding optical signals;
the binary code generation module outputs '0' or '1' to determine the output signal of the microwave driving module, and further controls the variable single-sideband modulation module to output a single-sideband modulation signal of +1 order sideband or a single-sideband modulation signal of-1 order sideband.
In the device, the light source is a monochromatic laser light source and comprises a semiconductor laser, a solid laser or a fiber laser.
In the device, the variable single sideband modulation module is a dual-drive Mach-Zehnder modulator or a dual-parallel Mach-Zehnder modulator and works in a single sideband modulation state.
In the device, a phase modulation module is a phase modulator, a double-sideband modulation signal is generated under the drive of an output signal of a microwave drive module, and the phase difference of +/-1 order sidebands is pi.
In the apparatus, a binary code generation block generates high or low levels representing "1" and "0".
In the device, a microwave driving module comprises two adjustable direct current voltage sources, a binary code driving module, an adjustable microwave source, a power divider and a 90-degree phase shifter, the two adjustable direct current voltage sources respectively control direct current bias of a phase modulation module and a variable single-sideband modulation module, the binary code driving module realizes that the variable single-sideband modulation module outputs carrier waves and-1-order sidebands or the carrier waves and + 1-order sidebands by setting a high level value or a low level value, and the adjustable microwave source combines the power divider and the 90-degree phase shifter to provide modulation signals for the phase modulation module and the variable single-sideband modulation module.
In the device, the photoelectric transceiving module comprises a beam combiner, a photoelectric detector and a radio frequency amplifier, wherein the beam combiner converts two paths of modulated optical signals into electric signals after combining the electric signals, and then the electric signals are amplified by the radio frequency amplifier and then radio frequency phase coding signals are output.
The specific method for generating the radio frequency phase coding signal based on the invention comprises the following steps:
the method comprises the steps that a binary code generating module is used for compiling required binary codes in advance;
turning on a light source;
adjusting two direct current voltages of the microwave driving module to enable the phase difference between the direct current bias of the phase modulation module and the direct current bias of the variable single-sideband modulation module to be pi or-pi;
setting the output frequency and power of an adjustable microwave source of a microwave driving module;
setting high and low level values of the binary code driving module to make the difference between the phase corresponding to the two level states and the phase corresponding to the DC bias of the variable single-sideband modulation module be
Setting the radio frequency gain of the photoelectric transceiving module;
and starting the binary code generation module and the photoelectric transceiving module to obtain a pre-programmed radio frequency phase coding signal.
(III) advantageous effects
Compared with the prior art, the invention has the following advantages:
the device and the method for generating the radio frequency phase coding signal based on the microwave photon technology have the advantages of simple structure, large dynamic range, tunability and the like, and can generate the radio frequency phase coding signal with tunable carrier frequency and large bandwidth.
Drawings
FIG. 1 is a schematic structural diagram of an RF phase-encoded signal generating apparatus based on microwave photonic technology according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of an RF phase-encoded signal generating apparatus based on microwave photonic technology according to an embodiment of the present invention;
FIG. 3 is a spectral diagram of a light source in an embodiment of the invention;
FIG. 4 shows the-1 th sideband and carrier output from a dual drive Mach-Zehnder modulator in an embodiment of the present invention;
FIG. 5 shows the carrier and +1 order sidebands output by the dual drive Mach-Zehnder modulator in an embodiment of the present invention;
FIG. 6 shows the output level of the microwave driver module in an embodiment of the present invention;
FIG. 7 is an RF phase encoded signal output in an embodiment of the present invention;
FIG. 8 is a microwave driver module according to an embodiment of the invention;
fig. 9 is an optoelectronic transceiver module according to an embodiment of the present invention.
Detailed Description
In order that the objects, technical solutions and advantages of the present invention will become more apparent, the present invention will be further described in detail with reference to the accompanying drawings in conjunction with the following specific embodiments.
The radio frequency phase encoding signal generating device based on the microwave photon technology, as shown in fig. 1, includes: the device comprises a light source, a variable single-sideband modulation module, a phase modulation module, a binary code generation module, a microwave driving module and a photoelectric transceiving module.
The light source, the variable single-side band modulation module and the phase modulation module are connected with the photoelectric transceiving module through optical fibers, the light source, the variable single-side band modulation module and the photoelectric transceiving module are connected into one path, and the light source, the phase modulation module and the photoelectric transceiving module are connected into the other path.
Based on the embodiment provided by the present invention, please refer to fig. 2.
In the invention, the light source is a monochromatic laser light source and comprises a semiconductor laser, a solid laser or a fiber laser.
In this embodiment, the light source is a narrow linewidth semiconductor laser, but not limited to a semiconductor laser, and the output wavelength is 1550nm, and the output spectrum is shown in fig. 3.
In the invention, the variable single sideband modulation module is a dual-drive Mach-Zehnder modulator or a dual-parallel Mach-Zehnder modulator and works in a single sideband modulation state.
In this embodiment, the variable single sideband modulation module is a dual drive mach-zehnder modulator having a half-wave voltage Vπm＝5V。
In the invention, the phase modulation module is a phase modulator, and generates a double-sideband modulation signal under the drive of the output signal of the microwave drive module, and the phase difference of +/-1 order sidebands is pi.
In this embodiment, the phase modulation module is a phase modulator with half-wave powerPressure Vπp＝5V。
In the invention, light emitted by a light source is divided into two paths by a beam splitter, wherein one path is sent to a variable single-sideband modulation module, an output signal of a microwave driving module is used for driving to generate a single-sideband modulated optical signal, the optical signal consists of a carrier and a + 1-order sideband or the carrier and a-1-order sideband, the other path is sent to a phase modulation module, an output signal of the microwave driving module is used for driving to generate a phase modulated optical signal, the two paths of modulated optical signals are combined into one path by a beam combiner and then sent to a photoelectric transceiving module, and finally, a radio frequency phase coding signal is output.
In this embodiment, light emitted by the semiconductor laser is equally divided into two paths by the beam splitter, wherein one path a) is sent to the variable single-sideband modulation module, i.e., the dual-drive mach-zehnder modulator, and the other path b) is sent to the phase modulation module, i.e., the phase modulator.
The output signal of the microwave driving module drives and controls the variable single-sideband modulation module and the phase modulation module to generate corresponding optical signals.
For the path b), the microwave driving module outputs a microwave signal vb(t)＝Vb+Vpsin(ωmt)，VbFor the DC bias voltage applied to the phase modulator, V is set in this embodimentb＝10V，Vpsin(ωmt) is the microwave modulation signal applied to the phase modulator. The output light of the phase modulation module can be expressed as:
In this embodiment, the microwave signal is small, and the output light of the phase modulation module is expressed by jacobian expansion under the approximation of the small signal:
as can be seen from this equation, the output light of the phase modulation module consists of the carrier and the ± 1 order sidebands. The phase difference between the microwave signal obtained by the +1 order sideband and the carrier beat frequency and the phase difference between the microwave signal obtained by the-1 order sideband and the carrier beat frequency are pi, so that the radio frequency signal cannot be detected by directly detecting with the photoelectric detector.
For the a) path, the two arms of the dual drive mach-zehnder modulator apply the drives of: v. ofa(t)＝Va1+Vmcos(ωmt)，va(t)＝Va2+Vmsin(ωmt). The optical fields of the two arms of the modulator are respectively:
also under the small signal approximation, the photoelectric fields of the two arms are expanded into by using a Jacobian expansion formula:
the total output optical field of the dual-drive Mach-Zehnder modulator is as follows:
wherein
When in useWhen the temperature of the water is higher than the set temperature,
In the embodiment of the invention, the binary code generation module outputs '0' or '1' to determine the output signal of the microwave driving module, so as to control the variable single sideband modulation module to output a single sideband modulation signal of +1 order sideband or a single sideband modulation signal of-1 order sideband.
Based on the above embodiment, will
In the embodiment of the invention, the binary code generation module generates high level or low level representing 1 and 0, the generated coding sequence can be customized by a user, and the generation rate of the binary code can also be set by the user.
Based on the above embodiments, the phase is adjusted
The microwave driving module comprises two adjustable direct current voltage sources, a binary code driving module, an adjustable microwave source, a power divider and a 90-degree phase shifter, the two adjustable direct current voltage sources respectively control direct current biases of the phase modulation module and the variable single-sideband modulation module, the binary code driving module realizes that the variable single-sideband modulation module outputs carrier waves and-1-order sidebands or carrier waves and + 1-order sidebands by setting a high level value or a low level value, the microwave source combines the power divider and the 90-degree phase shifter to provide modulation signals for the corresponding modulation module and the variable single-sideband modulation module, and detailed connection and arrangement modes refer to fig. 2 and 8.
The photoelectric transceiver module is composed of a beam combiner, a photoelectric detector and a radio frequency amplifier, converts two paths of modulated optical signals into electric signals after being combined by the photoelectric detector, amplifies the electric signals by the radio frequency amplifier and then outputs radio frequency phase encoded signals, and the detailed connection and arrangement mode refers to fig. 2 and fig. 9.
The device based on the embodiment of the invention also provides a specific method for generating the radio frequency phase coding signal, and the detailed steps comprise:
predefining a binary code sequence in the binary code generation module;
turning on a light source;
in this embodiment, the light source is a semiconductor laser, and the detailed description is already presented in the above process, which is not described herein.
Adjusting two direct current voltages of the microwave driving module to enable the phase difference between the direct current bias of the phase modulation module and the direct current bias of the variable single-sideband modulation module to be pi or-pi;
in this embodiment, the technical adjustment scheme for the phase difference between the phase modulation module and the variable single-sideband modulation module is already embodied in the above process, and is not described herein again.
Setting the output frequency and power of an adjustable microwave source of a microwave driving module;
setting high level or low level value of binary code driving module to make the difference between the phase corresponding to two level states and the phase corresponding to DC bias of variable single-sideband modulation module be
Setting the radio frequency gain of the photoelectric transceiving module;
and starting the binary code generation module and the photoelectric transceiving module to obtain a pre-programmed radio frequency phase coding signal.
The implementation process of the method is already embodied in the above embodiments, and is not described herein again.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.