A device for generating and transmitting optically generated millimeter waves

Abstract

The invention discloses a device for generating and transmitting photogenerated millimeter waves, belonging to the field of photogenerated millimeter waves, comprising a first laser, a second laser, a first beam splitter, a second beam splitter, a dual-laser frequency locking module, a local output module and an optical fiber transmission link module. The dual-laser frequency locking module comprises a first frequency locking module, a second frequency locking module, a first beam combiner and an optical reference cavity. The first frequency locking module and the second frequency locking module are both connected to the first beam combiner, the first beam combiner is connected to the optical reference cavity, the first beam splitter is connected to the first frequency locking module, the second beam splitter is connected to the second frequency locking module, the local output module and the optical fiber transmission link module are both connected to the first beam splitter, and the local output module and the optical fiber transmission link module are both connected to the second beam splitter, thereby improving the frequency stability and signal quality of the millimeter wave signal.

Description

Technical Field

[0001] The present invention belongs to the technical field of photogenerated millimeter waves, and in particular relates to a device for generating and transmitting photogenerated millimeter waves. Background Art

[0002] In recent years, with the rapid development and iteration of communication technology, mobile communication technology is about to enter the 6G era. However, with the explosive growth of communication demand, the resources of commonly used medium and low frequency bands have become crowded, making it difficult for medium and low frequency bands to meet the growing communication needs. In contrast, the millimeter wave band from 30 GHz to 300 GHz has richer bandwidth resources and supports higher information transmission rates and greater communication capacity. Therefore, this millimeter wave band can meet the needs of high-speed, large-capacity, and low-latency mobile communications. In addition, high-quality millimeter waves are also widely used in radar systems, time synchronization, sensor technology, astronomical observations and other fields.

[0003] Existing millimeter wave generation technologies are mainly divided into electronic methods and optical methods. Among them, the electronic method uses traditional radio frequency and microwave technology to directly or indirectly generate millimeter wave signals through electronic devices. However, as the frequency response of electronic equipment is limited, it is more difficult and costly to generate millimeter wave signals using traditional electronic methods. The optical method uses photon technology to generate millimeter wave signals.

[0004] Generally, the device for generating and transmitting optically generated millimeter waves includes two lasers and a photodetector. The two lasers emit a first laser and a second laser respectively. The photodetector can generate a millimeter wave signal by detecting the optical heterodyne signal of the first laser and the second laser. However, due to the phase irrelevance of the first laser and the second laser, the millimeter wave signal generated by mixing the photodetector will be affected by the laser phase noise, which will lead to the decrease of the frequency stability and signal quality of the millimeter wave signal. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a device for generating and transmitting optically generated millimeter waves. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0006] The present invention provides a device for generating and transmitting optically generated millimeter waves, comprising a first laser, a second laser, a first beam splitter, a second beam splitter, a dual-laser frequency locking module, a local end output module and an optical fiber transmission link module, wherein both the first laser and the second laser are frequency tunable lasers;

[0007] The first laser is used to emit a first laser, and the first beam splitter is connected to the first laser to split the first laser into a first main beam, a second main beam and a third main beam;

[0008] The second laser is used to emit a second laser, and the second beam splitter is connected to the second laser to split the second laser into a first sub-beam, a second sub-beam and a third sub-beam;

[0009] The dual-laser frequency locking module includes a first frequency locking module, a second frequency locking module, a first beam combiner and an optical reference cavity. The first frequency locking module and the second frequency locking module are both connected to the first beam combiner, the first beam combiner is connected to the optical reference cavity, the first beam splitter is connected to the first frequency locking module, the first main light splitting is transmitted to the first frequency locking module, the second beam splitter is connected to the second frequency locking module, and the first slave light splitting is transmitted to the second frequency locking module;

[0010] The local output module and the optical fiber transmission link module are both connected to the first splitter, and the local output module and the optical fiber transmission link module are both connected to the second splitter, the second main split and the second slave split are both transmitted to the local output module, and the third main split and the third slave split are both transmitted to the optical fiber transmission link module.

[0011] In one embodiment of the present invention, the first frequency locking module includes a first electro-optic modulator, a first circulator, a first photodetector and a first frequency locking module which are connected in sequence, the first electro-optic modulator is connected to the first beam splitter, the first circulator is connected to the first beam combiner, and the first frequency locking module is connected to the first laser;

[0012] The first main split light enters the optical reference cavity through the first electro-optic modulator, the first circulator and the first beam combiner in sequence, and then enters the first laser through the first beam combiner, the first circulator, the first photodetector and the first frequency locking module in sequence after being emitted from the optical reference cavity.

[0013] In one embodiment of the present invention, the second frequency locking module includes a second electro-optic modulator, a second circulator, a second photodetector and a second frequency locking module connected in sequence, the second electro-optic modulator is connected to the second beam splitter, the second circulator is connected to the first beam combiner, and the second frequency locking module is connected to the second laser;

[0014] The first split light enters the optical reference cavity through the second electro-optic modulator, the second circulator and the first combiner in sequence, and then enters the second laser through the first combiner, the second circulator, the second photodetector and the second frequency locking module after being emitted from the optical reference cavity.

[0015] In one embodiment of the present invention, the local output module includes a second combiner and a first broadband photodetector. The second main beam and the second slave beam are combined to the first broadband photodetector through the second combiner and then beat by the first broadband photodetector to obtain the local millimeter wave.

[0016] In one embodiment of the present invention, the frequency of the local millimeter wave is: ;

[0017] in, is the output frequency of the first laser, is the output frequency of the second laser, and the frequency of the local end millimeter wave is a multiple of the free spectral region of the optical reference cavity.

[0018] In one embodiment of the present invention, the optical fiber transmission link module includes a first noise suppression module, a second noise suppression module, a third beam combiner and a transmission optical fiber, the first noise suppression module is connected to the first beam splitter, the second noise suppression module is connected to the second beam splitter, the first noise suppression module and the second noise suppression module are both connected to the third beam combiner, and the third beam combiner is connected to the transmission optical fiber;

[0019] The third main split light enters the third beam combiner through the first noise suppression module, and the third slave split light enters the third beam combiner through the second noise suppression module.

[0020] In one embodiment of the present invention, the first noise suppression module includes a first isolator, a third beam splitter, a first acousto-optic modulator, a first Faraday reflector, a third photodetector, and a first phase-locking module;

[0021] The first isolator is connected to the first beam splitter, the first isolator and the third photodetector are connected to one end of the third beam splitter, the first acousto-optic modulator and the first Faraday reflector are connected to the other end of the third beam splitter, the third photodetector, the first phase-locking module and the first acousto-optic modulator are connected in sequence, and the first acousto-optic modulator is connected to the third beam combiner;

[0022] The third main light is divided into a first light path and a second light path after passing through the first isolator and the third beam splitter in sequence. The first light path enters the first acousto-optic modulator, and enters the transmission optical fiber through the first acousto-optic modulator and the third beam combiner. The second light path is reflected by the first Faraday reflector to the third beam splitter, and reaches the third photodetector through the third beam splitter.

[0023] In one embodiment of the present invention, the second noise suppression module includes a second isolator, a fourth beam splitter, a second acousto-optic modulator, a second Faraday reflector, a fourth photodetector, and a second phase-locking module;

[0024] The second isolator is connected to the second beam splitter, the second isolator and the fourth photodetector are connected to one end of the fourth beam splitter, the second acousto-optic modulator and the second Faraday reflector are connected to the other end of the fourth beam splitter, the fourth photodetector, the second phase-locking module and the second acousto-optic modulator are connected in sequence, and the second acousto-optic modulator is connected to the third beam combiner;

[0025] The third light is divided into a third light path and a fourth light path after passing through the second isolator and the fourth beam splitter in sequence. The third light path enters the second acousto-optic modulator, and enters the transmission optical fiber through the second acousto-optic modulator and the third combiner. The fourth light path is reflected by the second Faraday reflector to the fourth beam splitter, and reaches the fourth photodetector through the fourth beam splitter.

[0026] In one embodiment of the present invention, the optical fiber transmission link module further includes a fifth beam splitter, a third Faraday reflector and a second broadband photodetector, the transmission optical fiber is connected to one end of the fifth beam splitter, and the third Faraday reflector and the second broadband photodetector are connected to the other end of the fifth beam splitter;

[0027] The laser in the transmission optical fiber enters the fifth beam splitter and is divided into a fifth light path and a sixth light path. The fifth light path enters the second broadband photodetector and is beat-frequencyed by the second broadband photodetector to obtain the receiving end millimeter wave. The sixth light path is reflected to the fifth beam splitter by the third Faraday reflector and is divided into a seventh light path and an eighth light path through the fifth beam splitter, the transmission optical fiber and the third combiner in turn. The seventh light path passes through the first acousto-optic modulator and the third beam splitter in turn to reach the third photodetector. The second light path and the seventh light path beat-frequencyed on the third photodetector to obtain a first phase-locked signal, which is fed back to the first acousto-optic modulator through the first phase-locked module. The eighth light path passes through the second acousto-optic modulator and the fourth beam splitter in turn to reach the fourth photodetector. The fourth light path and the eighth light path beat-frequencyed on the fourth photodetector to obtain a second phase-locked signal, which is fed back to the second acousto-optic modulator through the second phase-locked module.

[0028] In one embodiment of the present invention, the first AOM and the second AOM both use negative first-order diffracted light, and the frequency of the millimeter wave at the receiving end is: ;

[0029] in, is the output frequency of the first laser, is the output frequency of the second laser, is the modulation frequency of the first AOM, is the modulation frequency of the second AOM.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] In the above scheme of the present application, first, the dual-laser frequency locking module includes a first frequency locking module, a second frequency locking module, a first beam combiner and an optical reference cavity. The first laser forms a first main beam splitter through the first frequency locking module and enters the first beam combiner. The second laser forms a first slave beam splitter through the second frequency locking module and enters the first beam combiner. The first main beam splitter and the first slave beam splitter are combined by the first beam combiner, and the combined beam is transmitted to the optical reference cavity. With this structure, the optical reference cavity is used as a reference standard for frequency stability. The first laser and the second laser are respectively locked to the resonance frequency of the same optical reference cavity through the first frequency locking module and the second frequency locking module, so that the first laser and the second laser can be locked to the same frequency reference source, suppressing the drift of the laser frequency, thereby ensuring that the phases of the first laser and the second laser are highly correlated, avoiding the interference caused by the phase drift of the independent lasers, significantly improving the phase synchronization, frequency stability and spectrum purity of the millimeter wave signal, improving the frequency stability and signal quality of the millimeter wave signal, and having flexible frequency adjustment capabilities.

[0032] Secondly, the second main beam splitter formed by the first laser via the first beam splitter and the second slave beam splitter formed by the second laser via the second beam splitter can output millimeter wave signals through the local output module, and the third main beam splitter formed by the first laser via the first beam splitter and the third slave beam splitter formed by the second laser via the second beam splitter can output millimeter wave signals through the optical fiber transmission link module, so that both the local end and the receiving end can obtain millimeter wave signals.

[0033] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of a device for generating and transmitting optically generated millimeter waves provided in an embodiment of the present invention Figure 1 ;

[0035] Figure 2 Schematic diagram of a device for generating and transmitting optically generated millimeter waves provided in an embodiment of the present invention Figure 2 .

[0036] Figure numerals: 1-first laser, 2-second laser, 3-first beam splitter, 4-second beam splitter, 5-first electro-optic modulator, 6-first circulator, 7-first photodetector, 8-first frequency locking module, 9-second electro-optic modulator, 10-second circulator, 11-second photodetector, 12-second frequency locking module, 13-first beam combiner, 14-optical reference cavity, 15-second beam combiner, 16-first broadband photodetector, 17-second An isolator, 18-a third beam splitter, 19-a first acousto-optic modulator, 20-a first Faraday reflector, 21-a third photodetector, 22-a first phase-locking module, 23-a second isolator, 24-a fourth beam splitter, 25-a second acousto-optic modulator, 26-a second Faraday reflector, 27-a fourth photodetector, 28-a second phase-locking module, 29-a third beam combiner, 30-a fifth beam splitter, 31-a third Faraday reflector, 32-a second broadband photodetector. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0038] See also Figure 1 and Figure 2 The embodiment of the present invention provides a device for generating and transmitting optically generated millimeter waves, comprising a first laser 1, a second laser 2, a first beam splitter 3, a second beam splitter 4, a dual-laser frequency locking module, a local output module and an optical fiber transmission link module, wherein the first laser 1 and the second laser 2 are both frequency tunable lasers; the first laser 1 is used to emit a first laser, and the first beam splitter 3 is connected to the first laser 1 to split the first laser into a first main beam split, a second main beam split and a third main beam split; the second laser 2 is used to emit a second laser, and the second beam splitter 4 is connected to the second laser 2 to split the second laser into a first slave beam split, a second slave beam split and a third slave beam split; the dual-laser frequency locking module comprises a first lock The first frequency-locking module, the second frequency-locking module, the first combiner 13 and the optical reference cavity 14, the first frequency-locking module and the second frequency-locking module are both connected to the first combiner 13, the first combiner 13 is connected to the optical reference cavity 14, the first beam splitter 3 is connected to the first frequency-locking module, the first main light splitting is transmitted to the first frequency-locking module, the second beam splitter 4 is connected to the second frequency-locking module, and the first slave light splitting is transmitted to the second frequency-locking module; the local output module and the optical fiber transmission link module are both connected to the first beam splitter 3, and the local output module and the optical fiber transmission link module are both connected to the second beam splitter 4, the second main light splitting and the second slave light splitting are both transmitted to the local output module, and the third main light splitting and the third slave light splitting are both transmitted to the optical fiber transmission link module.

[0039] In some embodiments of the present application, a frequency tunable laser is a laser that can continuously change the laser output frequency within a certain range. The output wavelength of such a laser can be precisely controlled by adjusting parameters such as the laser cavity length, gain medium or filter, thereby achieving frequency regulation.

[0040] In some embodiments of the present application, the dual laser frequency locking module uses PDH (Pound Drever Hall) laser locking technology to lock the first laser and the second laser to the resonant frequency of the same optical reference cavity. PDH (Pound Drever Hall) laser locking technology is an active frequency locking technology used to lock the frequency of the laser to an ultra-stable optical cavity, thereby achieving laser frequency stability.

[0041] In some embodiments of the present application, Figure 1 and Figure 2 As shown, the first main beam splitting, the second main beam splitting and the third main beam splitting are respectively A1 beam, A2 beam and A3 beam; the first slave beam splitting, the second slave beam splitting and the third slave beam splitting are respectively B1 beam, B2 beam and B3 beam.

[0042] In the above scheme of the present application, first, the dual-laser frequency locking module includes a first frequency locking module, a second frequency locking module, a first beam combiner 13 and an optical reference cavity 14. The first laser is transmitted through the first main beam splitter 3 to form a first main beam splitter and enters the first beam combiner 13 through the first frequency locking module. The second laser is transmitted through the second beam splitter 4 to form a first slave beam splitter and enters the first beam combiner 13 through the second frequency locking module. The first main beam splitter and the first slave beam splitter are combined by the first beam combiner 13, and the combined light beam is transmitted to the optical reference cavity 14. With this structure, the optical reference cavity 14 is used as a reference standard for frequency stability, and the first laser and the second laser are respectively locked to the resonant frequency of the same optical reference cavity 14 through the first frequency locking module and the second frequency locking module, so that the first laser and the second laser can be locked to the same frequency reference source, suppressing the drift of the laser frequency, thereby ensuring that the phases of the first laser and the second laser are highly correlated, avoiding interference caused by phase drift of independent lasers, significantly improving the phase synchronization, frequency stability and spectral purity of the millimeter-wave signal, improving the frequency stability and signal quality of the millimeter-wave signal, and having flexible frequency adjustment capabilities.

[0043] Secondly, the second main beam splitter formed by the first laser via the first beam splitter 3 and the second slave beam splitter formed by the second laser via the second beam splitter 4 can output millimeter wave signals through the local output module, and the third main beam splitter formed by the first laser via the first beam splitter 3 and the third slave beam splitter formed by the second laser via the second beam splitter 4 can output millimeter wave signals through the optical fiber transmission link module, so that both the local end and the receiving end can obtain millimeter wave signals.

[0044] In some embodiments of the present application, Figure 2 As shown, the first frequency locking module includes a first electro-optic modulator 5, a first circulator 6, a first photodetector 7 and a first frequency locking module 8 which are connected in sequence. The first electro-optic modulator 5 is connected to the first beam splitter 3, the first circulator 6 is connected to the first beam combiner 13, and the first frequency locking module 8 is connected to the first laser 1; the first main split light enters the optical reference cavity 14 through the first electro-optic modulator 5, the first circulator 6 and the first beam combiner 13 in sequence, and after being emitted from the optical reference cavity 14, enters the first laser 1 through the first beam combiner 13, the first circulator 6, the first photodetector 7 and the first frequency locking module 8 in sequence. With this structure, the first electro-optical modulator 5 performs phase modulation on the first main beam splitter to form an error signal, and the first circulator 6 guides the first main beam splitter into the first beam combiner 13 and the optical reference cavity 14. The transmitted light and the reflected light in the optical reference cavity 14 pass through the first beam combiner 13 and enter the first circulator 6 again, and enter the first photodetector 7 under the guidance of the first circulator 6. The first photodetector 7 beats the frequency to obtain a discrimination signal, and the discrimination signal is fed back to the first laser 1 after passing through the first frequency locking module 8, so that the frequency of the first laser can be locked on the resonance frequency of the optical reference cavity 14.

[0045] In some embodiments of the present application, an electro-optic modulator (EOM) is a device that modulates an optical signal by changing the optical properties of a material through an external electric field. In the embodiment of the present application, the first electro-optic modulator 5 is mainly used to modulate the frequency or phase of the laser. After the first main beam is modulated by the first electro-optic modulator 5, an error signal can be generated so that there is a difference between the laser frequency of the first main beam and the resonant frequency of the optical reference cavity 14, so that the first main beam can be detected and measured.

[0046] In some embodiments of the present application, the first circulator 6 is used to guide and control the direction of the laser signal to ensure that the first main split light can propagate along a predetermined path, thereby ensuring the stability and accuracy of the signal.

[0047] In some embodiments of the present application, the optical reference cavity 14 is composed of two face-to-face parallel low-loss, high-reflection lenses. The optical reference cavity 14 is used to provide a stable reference standard for the laser frequency. By adjusting the frequencies of the first laser and the second laser, the first laser and the second laser can match the resonant frequency of the optical reference cavity 14, thereby achieving high-precision locking of the laser frequency.

[0048] In some embodiments of the present application, the first photodetector 7 is used to receive the laser signal reflected from the optical reference cavity 14 and convert it into an electrical signal to obtain a discrimination signal, which reflects the difference between the laser frequency and the resonant frequency of the optical reference cavity 14, and can be used as a reference signal for adjustment of the first frequency locking module 8.

[0049] In some embodiments of the present application, the first frequency locking module 8 is used to adjust the frequency of the first laser 1 through a series of electronic devices (such as a waveform generator, a mixer, a low-pass filter, and a PID controller, etc.) according to the frequency discrimination signal generated by the first photodetector 7. The function of the first frequency locking module 8 is to stabilize the frequency of the first laser 1 at the resonant frequency of the optical reference cavity 14, thereby ensuring the stability and accuracy of the millimeter wave signal.

[0050] In some embodiments of the present application, Figure 2 As shown, the second frequency locking module includes a second electro-optic modulator 9, a second circulator 10, a second photodetector 11 and a second frequency locking module 12 connected in sequence, the second electro-optic modulator 9 is connected to the second beam splitter 4, the second circulator 10 is connected to the first beam combiner 13, and the second frequency locking module 12 is connected to the second laser 2; the first split light sequentially enters the optical reference cavity 14 through the second electro-optic modulator 9, the second circulator 10 and the first beam combiner 13, and after being emitted from the optical reference cavity 14, it sequentially enters the second laser 2 through the first beam combiner 13, the second circulator 10, the second photodetector 11 and the second frequency locking module 12. With this structure, the second electro-optic modulator 9 performs phase modulation on the second main beam splitter to form an error signal, and the second circulator 10 guides the second main beam splitter into the first beam combiner 13 and the optical reference cavity 14. The transmitted light and the reflected light in the optical reference cavity 14 pass through the first beam combiner 13 and enter the second circulator 10 again, and enter the second photodetector 11 under the guidance of the second circulator 10, and obtain a discrimination signal by beating the second photodetector 11. The discrimination signal is fed back to the second laser 2 after passing through the second frequency locking module 12, so that the frequency of the second laser can be locked on the resonance frequency of the optical reference cavity 14.

[0051] In some embodiments of the present application, the second electro-optic modulator 9 is mainly used to modulate the frequency or phase of the laser. After the second main beam is modulated by the second electro-optic modulator 9, an error signal can be generated to make a difference between the laser frequency of the second main beam and the resonant frequency of the optical reference cavity 14, so that the second main beam can be detected and measured.

[0052] In some embodiments of the present application, the second circulator 10 is used to guide and control the direction of the laser signal to ensure that the second main split light can propagate along a predetermined path, thereby ensuring the stability and accuracy of the signal.

[0053] In some embodiments of the present application, the second photodetector 11 is used to receive the laser signal reflected from the optical reference cavity 14 and convert it into an electrical signal to obtain a discrimination signal, which reflects the difference between the laser frequency and the resonant frequency of the optical reference cavity 14, and can be used as a reference signal for adjustment of the second frequency locking module 12.

[0054] In some embodiments of the present application, the second frequency locking module 12 is used to adjust the frequency of the second laser 2 through a series of electronic devices (such as a waveform generator, a mixer, a low-pass filter, and a PID controller, etc.) according to the discrimination signal generated by the second photodetector 11. The function of the second frequency locking module 12 is to stabilize the frequency of the second laser 2 at the resonant frequency of the optical reference cavity 14, thereby ensuring the stability and accuracy of the millimeter wave signal.

[0055] In some embodiments of the present application, the modulation frequencies of the first electro-optic modulator 5 and the second electro-optic modulator 9 are respectively and After the first photodetector 7 and the second photodetector 11 beat, the center frequencies can be obtained as and The frequency discrimination signal.

[0056] In some embodiments of the present application, Figure 2 As shown, the local output module includes a second beam combiner 15 and a first broadband photodetector 16. The second main beam and the second slave beam are combined to the first broadband photodetector 16 by the second beam combiner 15, and the local millimeter wave is obtained by beating the first broadband photodetector 16. With this structure, the second main beam and the second slave beam are combined into one beam by the second beam combiner 15, and the optical signal is converted into an electrical signal by the first broadband photodetector 16, so that the local millimeter wave signal can be obtained.

[0057] In some embodiments of the present application, a broadband photodetector is a light receiving device that converts an input optical signal into an electrical signal using the photoelectric effect, and is mainly composed of a detection element, a preamplifier, an output circuit, and other components.

[0058] In some embodiments of the present application, the frequency of the local millimeter wave is: ;

[0059] in, is the output frequency of the first laser 1, is the output frequency of the second laser 2, and the frequency of the local end millimeter wave is a multiple of the free spectrum range of the optical reference cavity 14, that is, and The absolute value of the difference is a multiple of the free spectrum region of the optical reference cavity 14. With this structure, a millimeter wave signal of a specific frequency can be obtained, thereby improving the accuracy of the millimeter wave signal.

[0060] In some embodiments of the present application, is the output frequency of the first laser 1 after frequency locking, is the output frequency of the second laser 2 after frequency locking, and the free spectrum range F of the optical reference cavity 14 is F=c / 2L, where c is the speed of light and L is the cavity length of the optical reference cavity 14.

[0061] In one embodiment, the optical reference cavity 14 has a cavity length of 10 cm, a free spectrum region of 1.5 GHz, and the frequency of the local end millimeter wave changes in steps of 1.5 GHz.

[0062] In some embodiments of the present application, the optical fiber transmission link module includes a first noise suppression module, a second noise suppression module, a third beam combiner 29 and a transmission optical fiber. The first noise suppression module is connected to the first beam splitter 3, the second noise suppression module is connected to the second beam splitter 4, the first noise suppression module and the second noise suppression module are both connected to the third beam combiner 29, and the third beam combiner 29 is connected to the transmission optical fiber; the third main split light enters the third beam combiner 29 through the first noise suppression module, and the third slave split light enters the third beam combiner 29 through the second noise suppression module. With this structure, the laser emitted by the first laser 1 is subjected to phase noise suppression through the first noise suppression module, the laser emitted by the second laser 2 is subjected to phase noise suppression through the second noise suppression module, the two laser beams are combined into one laser beam through the third beam combiner 29, and transmitted through the same transmission optical fiber, which can improve the phase stability and spectrum purity of the millimeter wave signal at the receiving end, thereby achieving low-loss and long-distance signal transmission.

[0063] In some embodiments of the present application, Figure 2As shown, the first noise suppression module includes a first isolator 17, a third beam splitter 18, a first acousto-optic modulator 19, a first Faraday reflector 20, a third photodetector 21 and a first phase-locking module 22; the first isolator 17 is connected to the first beam splitter 3, the first isolator 17 and the third photodetector 21 are connected to one end of the third beam splitter 18, the first acousto-optic modulator 19 and the first Faraday reflector 20 are connected to the other end of the third beam splitter 18, the third photodetector 21, the first phase-locking module 22 and the first phase-locking module 22 are connected to the first beam splitter 3, the first isolator 17 and the third photodetector 21 are connected to one end of the third beam splitter 18, the first acousto-optic modulator 19 and the first Faraday reflector 20 are connected to the other end of the third beam splitter 18, and the third photodetector 21, the first phase-locking module 22 and the first phase-locking module 22 are connected to the first beam splitter 3. The phase module 22 is connected to the first acousto-optic modulator 19 in sequence, and the first acousto-optic modulator 19 is connected to the third beam combiner 29; the third main light is divided into the first light and the second light after passing through the first isolator 17 and the third beam splitter 18 in sequence, the first light enters the first acousto-optic modulator 19, and enters the transmission optical fiber through the first acousto-optic modulator 19 and the third beam combiner 29, the second light is reflected to the third beam splitter 18 through the first Faraday reflector 20, and reaches the third photodetector 21 through the third beam splitter 18. With this structure, the third main light can be split into the first light and the second light by the third beam splitter 18, the first light can enter the transmission optical fiber for transmission, so that the signal can be transmitted normally, and the second light can be reflected to the third photodetector 21, so as to beat with the seventh light after reflection on the third photodetector 21, so as to suppress the phase noise of the transmission optical fiber.

[0064] In some embodiments of the present application, the first isolator 17 is used to isolate the reflected light beam after being reflected by the first Faraday reflector 20 and the third Faraday reflector 31 to prevent the reflected light beam from affecting the first laser 1 .

[0065] In some embodiments of the present application, the second path of light does not pass through the transmission optical fiber.

[0066] In some embodiments of the present application, the third photodetector 21 is used to convert the optical signals of the second light path and the seventh light path into electrical signals to obtain a first phase detection signal, and the first phase detection signal can be used as a reference signal for adjustment of the first phase locking module 22.

[0067] In some embodiments of the present application, the phase-locked module is also called a phase-locked loop (PLL), which is a closed-loop automatic control system that uses an external reference signal to control the frequency and phase of the internal oscillation signal of the loop, thereby achieving automatic tracking of the output signal frequency to the input signal frequency. In the embodiment of the present application, after the first phase-locked signal is fed back to the first acousto-optic modulator 19 through the first phase-locked module 22, the transmission fiber phase noise can be suppressed.

[0068] In some embodiments of the present application, an acousto-optic modulator (AOM) is a device that uses the acousto-optic effect to achieve light modulation.

[0069] In some embodiments of the present application, Figure 2 As shown, the second noise suppression module includes a second isolator 23, a fourth beam splitter 24, a second acousto-optic modulator 25, a second Faraday reflector 26, a fourth photodetector 27 and a second phase-locking module 28; the second isolator 23 is connected to the second beam splitter 4, the second isolator 23 and the fourth photodetector 27 are connected to one end of the fourth beam splitter 24, the second acousto-optic modulator 25 and the second Faraday reflector 26 are connected to the other end of the fourth beam splitter 24, the fourth photodetector 27, the second phase-locking module 28 and the second acousto-optic modulator 25 are connected in sequence, and the second acousto-optic modulator 25 is connected to the third beam combiner 29; the third light is divided into a third light path and a fourth light path after passing through the second isolator 23 and the fourth beam splitter 24 in sequence, the third light path enters the second acousto-optic modulator 25, and enters the transmission optical fiber through the second acousto-optic modulator 25 and the third beam combiner 29, the fourth light path is reflected to the fourth beam splitter 24 by the second Faraday reflector 26, and reaches the fourth photodetector 27 through the fourth beam splitter 24. By adopting this structure, the fourth beam splitter 24 can be used to split the third light beam into a third light path and a fourth light path. The third light path can enter the transmission optical fiber for transmission so that the signal can be transmitted normally. The fourth light path can be reflected to the fourth photodetector 27 so as to beat with the reflected eighth light path on the fourth photodetector 27 to suppress the phase noise of the transmission optical fiber.

[0070] In some embodiments of the present application, the second isolator 23 is used to isolate the reflected light beam after being reflected by the second Faraday reflector 26 and the third Faraday reflector 31 to prevent the reflected light beam from affecting the second laser 2 .

[0071] In some embodiments of the present application, the fourth photodetector 27 is used to convert the optical signals of the fourth light path and the eighth light path into electrical signals to obtain a second phase detection signal, and the second phase detection signal can be used as a reference signal for adjustment of the second phase locking module 28.

[0072] In some embodiments of the present application, after the second phase detection signal is fed back to the second acousto-optic modulator 25 through the second phase locking module 28, the transmission optical fiber phase noise can be suppressed.

[0073] In some embodiments of the present application, Figure 2As shown, the optical fiber transmission link module also includes a fifth beam splitter 30, a third Faraday reflector 31 and a second broadband photodetector 32. The transmission optical fiber is connected to one end of the fifth beam splitter, and the third Faraday reflector 31 and the second broadband photodetector 32 are connected to the other end of the fifth beam splitter 30. The laser in the transmission optical fiber enters the fifth beam splitter 30 and is divided into a fifth light path and a sixth light path. The fifth light path enters the second broadband photodetector 32 and is beat by the second broadband photodetector 32 to obtain a receiving end millimeter wave. The sixth light path is reflected by the third Faraday reflector 31 to the fifth beam splitter 30, and is sequentially passed through the fifth beam splitter 30, the transmission optical fiber 30 and the transmission optical fiber 31. The optical fiber and the third beam combiner 29 are divided into a seventh light path and an eighth light path. The seventh light path passes through the first acousto-optic modulator 19 and the third beam splitter 18 in sequence to reach the third photodetector 21. The second light path and the seventh light path beat on the third photodetector 21 to obtain a first phase-locked signal. The first phase-locked signal is fed back to the first acousto-optic modulator 19 through the first phase-locked module 22. The eighth light path passes through the second acousto-optic modulator 25 and the fourth beam splitter 24 in sequence to reach the fourth photodetector 27. The fourth light path and the eighth light path beat on the fourth photodetector to obtain a second phase-locked signal. The second phase-locked signal is fed back to the second acousto-optic modulator 25 through the second phase-locked module 28. With this structure, the fifth light path can directly enter the second broadband photodetector 32 to obtain the millimeter wave signal at the receiving end. The sixth light path first returns along the original path and enters the third beam combiner 29, and is divided into the seventh light path and the eighth light path through the third beam combiner 29. The seventh light path passes through the first acousto-optic modulator 19 and the third beam splitter 18 in turn to reach the third photodetector 21. The second light path and the seventh light path beat on the third photodetector 21 to obtain a first phase detection signal, which is fed back to the first acousto-optic modulator 19 through the first phase-locking module 22, so that the phase noise of the transmission fiber can be suppressed; the eighth light path passes through the second acousto-optic modulator 25 and the fourth beam splitter 24 in turn to reach the fourth photodetector 27, and the fourth light path and the eighth light path beat on the fourth photodetector to obtain a second phase detection signal, which is fed back to the second acousto-optic modulator 25 through the second phase-locking module 28, so that the phase noise of the transmission fiber can be suppressed, thereby improving the phase stability and spectrum purity of the millimeter wave signal at the receiving end.

[0074] In some embodiments of the present application, the first AOM 19 and the second AOM 25 both use negative first-order diffracted light, and the frequency of the millimeter wave at the receiving end is: ;

[0075] in, is the output frequency of the first laser 1, is the output frequency of the second laser 2, is the modulation frequency of the first acousto-optic modulator 19, is the modulation frequency of the second AOM 25. and , the frequency adjustment of millimeter waves at the output end can be achieved.

[0076] In the present invention, the terms "first", "second", "third", "fourth", "fifth", "sixth", "seventh" and "eighth" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", "third", "fourth", "fifth", "sixth", "seventh" and "eighth" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0077] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0078] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0079] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A device for generating and transmitting optically generated millimeter waves, characterized in that: It includes a first laser, a second laser, a first beam splitter, a second beam splitter, a dual-laser frequency locking module, a local output module and an optical fiber transmission link module, wherein the first laser and the second laser are both frequency tunable lasers; The first laser is used to emit a first laser, and the first beam splitter is connected to the first laser to split the first laser into a first main beam, a second main beam and a third main beam; The second laser is used to emit a second laser, and the second beam splitter is connected to the second laser to split the second laser into a first sub-beam, a second sub-beam and a third sub-beam; The dual-laser frequency locking module includes a first frequency locking module, a second frequency locking module, a first beam combiner and an optical reference cavity, the first frequency locking module and the second frequency locking module are both connected to the first beam combiner, the first beam combiner is connected to the optical reference cavity, the first beam splitter is connected to the first frequency locking module, the first main beam splitter is transmitted to the first frequency locking module, the second beam splitter is connected to the second frequency locking module, and the first slave beam splitter is transmitted to the second frequency locking module; The local output module and the optical fiber transmission link module are both connected to the first beam splitter, and the local output module and the optical fiber transmission link module are both connected to the second beam splitter, the second main split and the second slave split are both transmitted to the local output module, and the third main split and the third slave split are both transmitted to the optical fiber transmission link module; The optical fiber transmission link module includes a first noise suppression module, a second noise suppression module, a third beam combiner and a transmission optical fiber, the first noise suppression module is connected to the first beam splitter, the second noise suppression module is connected to the second beam splitter, the first noise suppression module and the second noise suppression module are both connected to the third beam combiner, and the third beam combiner is connected to the transmission optical fiber; The third main split light enters the third beam combiner through the first noise suppression module, and the third slave split light enters the third beam combiner through the second noise suppression module; Wherein, the first noise suppression module includes a first isolator, a third beam splitter, a first acousto-optic modulator, a first Faraday reflector, a third photodetector and a first phase-locking module; The first isolator is connected to the first beam splitter, the first isolator and the third photodetector are connected to one end of the third beam splitter, the first acousto-optic modulator and the first Faraday reflector are connected to the other end of the third beam splitter, the third photodetector, the first phase-locked module and the first acousto-optic modulator are connected in sequence, and the first acousto-optic modulator is connected to the third beam combiner; The third main split light is divided into a first light path and a second light path after passing through the first isolator and the third beam splitter in sequence, the first light path enters the first acousto-optic modulator, and enters the transmission optical fiber through the first acousto-optic modulator and the third beam combiner, the second light path is reflected by the first Faraday reflector to the third beam splitter, and reaches the third photodetector through the third beam splitter; Wherein, the second noise suppression module includes a second isolator, a fourth beam splitter, a second acousto-optic modulator, a second Faraday reflector, a fourth photodetector and a second phase-locking module; The second isolator is connected to the second beam splitter, the second isolator and the fourth photodetector are connected to one end of the fourth beam splitter, the second acousto-optic modulator and the second Faraday reflector are connected to the other end of the fourth beam splitter, the fourth photodetector, the second phase-locking module and the second acousto-optic modulator are connected in sequence, and the second acousto-optic modulator is connected to the third beam combiner; The third light is divided into a third light path and a fourth light path after passing through the second isolator and the fourth beam splitter in sequence. The third light path enters the second acousto-optic modulator, and enters the transmission optical fiber through the second acousto-optic modulator and the third combiner. The fourth light path is reflected by the second Faraday reflector to the fourth beam splitter, and reaches the fourth photodetector through the fourth beam splitter.

2. The device for generating and transmitting optically generated millimeter waves according to claim 1, characterized in that: The first frequency locking module includes a first electro-optic modulator, a first circulator, a first photodetector and a first frequency locking module which are connected in sequence, the first electro-optic modulator is connected to the first beam splitter, the first circulator is connected to the first beam combiner, and the first frequency locking module is connected to the first laser; The first main split light enters the optical reference cavity through the first electro-optic modulator, the first circulator and the first beam combiner in sequence, and after being emitted from the optical reference cavity, enters the first laser through the first beam combiner, the first circulator, the first photodetector and the first frequency locking module in sequence.

3. The device for generating and transmitting optically generated millimeter waves according to claim 2, characterized in that: The second frequency locking module comprises a second electro-optic modulator, a second circulator, a second photodetector and a second frequency locking module which are connected in sequence, the second electro-optic modulator is connected to the second beam splitter, the second circulator is connected to the first beam combiner, and the second frequency locking module is connected to the second laser; The first split light enters the optical reference cavity through the second electro-optic modulator, the second circulator and the first combiner in sequence, and after being emitted from the optical reference cavity, enters the second laser through the first combiner, the second circulator, the second photodetector and the second frequency locking module in sequence.

4. The device for generating and transmitting optically generated millimeter waves according to claim 1, characterized in that: The local output module includes a second combiner and a first broadband photodetector. The second main beam splitter and the second slave beam splitter are combined by the second combiner to the first broadband photodetector and are beat by the first broadband photodetector to obtain a local millimeter wave.

5. The device for generating and transmitting optically generated millimeter waves according to claim 4, characterized in that: The frequency of the local millimeter wave is: ; in, is the output frequency of the first laser, is the output frequency of the second laser, and the frequency of the local end millimeter wave is a multiple of the free spectral range of the optical reference cavity.

6. The device for generating and transmitting optically generated millimeter waves according to claim 1, characterized in that: The optical fiber transmission link module further includes a fifth beam splitter, a third Faraday reflector and a second broadband photodetector, wherein the transmission optical fiber is connected to one end of the fifth beam splitter, and the third Faraday reflector and the second broadband photodetector are connected to the other end of the fifth beam splitter; The laser in the transmission optical fiber enters the fifth beam splitter and is divided into a fifth light path and a sixth light path. The fifth light path enters the second broadband photodetector and is beat by the second broadband photodetector to obtain a receiving end millimeter wave. The sixth light path is reflected to the fifth beam splitter by the third Faraday reflector and is divided into a seventh light path and an eighth light path through the fifth beam splitter, the transmission optical fiber and the third combiner in sequence. The seventh light path reaches the third photodetector in sequence through the first acousto-optic modulator and the third beam splitter. The second light path and the seventh light path beat on the third photodetector to obtain a first phase-locked signal, which is fed back to the first acousto-optic modulator through the first phase-locked module. The eighth light path reaches the fourth photodetector in sequence through the second acousto-optic modulator and the fourth beam splitter. The fourth light path and the eighth light path beat on the fourth photodetector to obtain a second phase-locked signal, which is fed back to the second acousto-optic modulator through the second phase-locked module.

7. The device for generating and transmitting optically generated millimeter waves according to claim 6, characterized in that: The first AOM and the second AOM both use negative first-order diffracted light, and the frequency of the receiving end millimeter wave is: ; in, is the output frequency of the first laser, is the output frequency of the second laser, is the modulation frequency of the first AOM, is the modulation frequency of the second AOM.

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