CN-116760478-B - High-linearity microwave photon down-conversion receiving system based on photoelectric oscillator

CN116760478BCN 116760478 BCN116760478 BCN 116760478BCN-116760478-B

Abstract

The invention relates to the technical field of microwave photons, in particular to a high-linearity microwave photon down-conversion receiving system based on a photoelectric oscillator. The system comprises a laser, a first phase modulator, a first optical amplifier, a phase-shift Bragg grating, a first photodetector, a second phase modulator, an optical filter, a second optical amplifier, and a second photodetector. According to the invention, the frequency of the local oscillation signal generated by the first photoelectric detector can be tuned by changing the frequency of the laser, so that the tuning of the down-conversion signal output by the second photoelectric detector is effectively realized. The amplitude of local oscillation spectrum harmonic in the optical signal output by the first phase modulator is a specific value by adjusting the gain value of the first optical amplifier, so that the third-order intermodulation distortion suppression in the output signal is realized, the spurious-free dynamic range of the whole down-conversion receiving system is further improved, the system has reconfigurability and high linearity, and the technical value can be exerted when the system is oriented to the application fields of radar and communication.

Inventors

ZHANG JIN
WANG YALAN
WANG DANGWEI
WANG ANLE
LIU XIAOTONG
CHEN HONG

Assignees

中国人民解放军空军预警学院

Dates

Publication Date: 20260508
Application Date: 20230518

Claims (10)

1. A high linearity microwave photon down-conversion receiving system based on an optoelectronic oscillator, comprising: the laser is used for outputting an optical carrier wave; the first phase modulator is arranged at the output end of the laser and used for modulating an optical carrier wave to generate a phase modulation signal; the first optical amplifier is arranged at the output end of the first phase modulator and used for receiving the phase modulation signal output by the first phase modulator and amplifying the phase modulation signal; the phase shift Bragg grating is arranged at one output end of the optical beam splitter and connected with the optical beam splitter through a circulator, and is used for filtering a phase modulation signal output by the optical beam splitter so as to retain an optical signal with a preset wavelength; The first photoelectric detector is respectively connected with the first phase modulator and the circulator, a port of the first photoelectric detector connected with the circulator is positioned at the downstream of a port of the phase-shift Bragg grating connected with the circulator and is used for receiving an optical signal with a preset wavelength output by the phase-shift Bragg grating, beating the optical signal to generate a local oscillation signal, and transmitting the generated local oscillation signal to the first phase modulator so that the local oscillation signal modulates the optical carrier; a low-noise amplifier is arranged between the first photoelectric detector and the first phase modulator and used for amplifying local oscillation signals output by the first photoelectric detector; The second phase modulator is arranged at one end of the optical beam splitter, which is far away from the circulator, and is used for receiving the modulated phase modulation signal split by the optical beam splitter and mixing the modulated phase modulation signal with a radio frequency signal transmitted to the second phase modulator; The optical filter is arranged at the output end of the second phase modulator and is used for filtering the signal output by the second phase modulator to filter out 0-order sidebands; The second optical amplifier is arranged at the output end of the optical filter and used for amplifying 0-order sidebands output by the optical filter; And the second photoelectric detector is arranged at the output end of the second optical amplifier and is used for beating the amplified 0-order sidebands so as to change the down-conversion output frequency.
2. The system of claim 1, wherein the first phase modulator mixes the local oscillator signal with the optical carrier to generate a double-sideband phase modulation spectrum when the local oscillator signal is received.
3. The system of claim 1, wherein the laser is capable of outputting optical carriers of different frequencies to enable the first photodetector to generate a local oscillator signal of a corresponding frequency.
4. The system of claim 1, wherein two adjacent components of the system for transmitting optical signals are connected by a single mode fiber.
5. The photoelectric oscillator-based high linearity microwave photon down-conversion receiving system according to claim 1, wherein said first photodetector is connected to said low noise amplifier by a radio frequency cable, and said low noise amplifier is connected to said first phase modulator by a radio frequency cable.
6. The high linearity microwave photon down-conversion receiving system based on photoelectric oscillator of claim 1, wherein the optical field output by the laser is represented by: Wherein T M is an attenuation coefficient generated by the transmission of the whole system, P IN is the optical power output by the laser, f C is the optical carrier frequency, e is an index, j is an imaginary number, T is the running time of the system, Setting the local oscillation signal V LO ＝V 0 sin2πf LO t, wherein f LO is the frequency of the local oscillation signal, and V 0 is the peak voltage of the local oscillation signal.
7. The optoelectronic oscillator-based high linearity microwave photon down-conversion receiving system of claim 1 wherein the laser is a distributed feedback laser.
8. The optoelectronic oscillator-based high linearity microwave photon down-conversion receiving system of claim 1, wherein the first optical amplifier and the second optical amplifier are erbium doped fiber amplifiers.
9. The photoelectric oscillator-based high linearity microwave photon down-conversion receiving system of claim 1, wherein said optical splitter is a 1:1 power splitter.
10. The optoelectronic oscillator-based high linearity microwave photon down-conversion receiving system of claim 1, wherein the first and second phase modulators are identical in operating parameters.

Description

High-linearity microwave photon down-conversion receiving system based on photoelectric oscillator Technical Field The invention relates to the technical field of microwave photons, in particular to a high-linearity microwave photon down-conversion receiving system based on a photoelectric oscillator. Background Microwave photonics is a novel cross subject combining photon technology and microwave technology, on one hand, mature electronic technology is applied to an optical system to collect and process signals, on the other hand, optical devices and systems are utilized to process microwave signals, and the great advantages of low loss, large bandwidth, long distance and the like of the optical technology are combined, so that the transmission distance of high-frequency radio is greatly increased, and the advantages and disadvantages of the photon technology and the microwave technology are complemented. Microwave photon frequency conversion is one of important applications of microwave photonics, and the prior art combines the advantages that a photoelectric oscillator (OEO) can generate a microwave signal with low phase noise and high frequency spectrum purity, and proposes a scheme for generating a high-frequency local oscillation signal by utilizing the OEO to carry out optical frequency mixing with a radio frequency input signal so as to realize microwave photon frequency conversion without external local oscillation input, but the promotion of the spurious-free dynamic range of the scheme is still limited by nonlinearity of a modulator. Therefore, for microwave photon down-conversion, how to use OEO to generate a high-frequency tunable local oscillator signal and at the same time achieve spurious-free dynamic range improvement is a challenge to be solved. Disclosure of Invention Therefore, the invention provides a high-linearity microwave photon down-conversion receiving system based on an optoelectronic oscillator. The method is used for solving the problem that the spurious-free dynamic range in the link cannot be effectively improved in the prior art. In order to achieve the above object, the present invention provides a high linearity microwave photon down-conversion receiving system based on an optoelectronic oscillator, comprising: the laser is used for outputting an optical carrier wave; the first phase modulator is arranged at the output end of the laser and used for modulating an optical carrier wave to generate a phase modulation signal; the first optical amplifier is arranged at the output end of the first phase modulator and used for receiving the phase modulation signal output by the first phase modulator and amplifying the phase modulation signal; the phase shift Bragg grating is arranged at one output end of the optical beam splitter and connected with the optical beam splitter through a circulator, and is used for filtering a phase modulation signal output by the optical beam splitter so as to retain an optical signal with a preset wavelength; The first photoelectric detector is respectively connected with the first phase modulator and the circulator, a port of the first photoelectric detector connected with the circulator is positioned at the downstream of a port of the phase-shift Bragg grating connected with the circulator and is used for receiving an optical signal with a preset wavelength output by the phase-shift Bragg grating, beating the optical signal to generate a local oscillation signal, and transmitting the generated local oscillation signal to the first phase modulator so that the local oscillation signal modulates the optical carrier; a low-noise amplifier is arranged between the first photoelectric detector and the first phase modulator and used for amplifying local oscillation signals output by the first photoelectric detector; The second phase modulator is arranged at one end of the optical beam splitter, which is far away from the circulator, and is used for receiving the modulated phase modulation signal split by the optical beam splitter and mixing the modulated phase modulation signal with a radio frequency signal transmitted to the second phase modulator; The optical filter is arranged at the output end of the second phase modulator and is used for filtering the signal output by the second phase modulator to filter out 0-order sidebands; The second optical amplifier is arranged at the output end of the optical filter and used for amplifying 0-order sidebands output by the optical filter; And the second photoelectric detector is arranged at the output end of the second optical amplifier and is used for beating the amplified 0-order sidebands so as to change the down-conversion output frequency. Further, the first phase modulator mixes the local oscillation signal and the optical carrier wave when receiving the local oscillation signal to generate a phase modulation spectrum with double sidebands. Further, the laser can output optical carriers with different freq