Distributed aperture OPA array common phase system based on phase measurement chip

Abstract

The present invention discloses a distributed aperture OPA array common phase system based on a phase measurement chip, which belongs to the field of laser radar. The output end of the laser generating device is connected to a fiber beam splitter to divide the output laser into two paths, one for the main light path and the other for the reference light path; after the main light path laser is amplified by a fiber amplifier, it is evenly divided into N paths by the fiber beam splitter, and each sub-beam enters the integrated optical chip through a fiber-waveguide coupler and is emitted via an OPA module; the reference light path laser enters the phase identification twin chip through a fiber-waveguide coupler; the on-chip interference result is fed back to the phase measurement compensation module, and the common phase synthesis technology in the waveguide is used to actively measure and correct the phase error in real time. The present invention uses a variety of main laser non-common light path phase error measurement methods to achieve a substantial improvement in the overall emission aperture, emission power and detection distance of the laser phased array in a multi-aperture collaborative coherent manner.

Description

Technical Field

[0001] The present invention belongs to the field of laser radar, and in particular relates to a distributed aperture OPA array common phase system based on a phase measurement chip. Background Art

[0002] Laser phased array (OPA) modulates the phase of light waves through array optical elements to achieve control of far-field light fields, similar to the principle of Young's double-slit interference. Integrated photonics laser phased array (PIC-OPA) combines integrated optoelectronics technology with OPA, using structures such as optical waveguides, phase shifters, and grating couplers, but is limited by input optical power and on-chip losses, making it difficult to achieve high-power output. In addition, due to the limitations of the driver chip and waveguide processing technology, the capabilities of a single OPA are limited and it is difficult to meet the needs of long-distance applications.

[0003] Therefore, to solve these problems, it is necessary to use multi-aperture OPA arrays to work together to improve the overall emission aperture and output power of the laser phased array and solve the problem of insufficient power of a single OPA in long-distance detection and communication; at the same time, it is necessary to study the coherent collaborative control technology of the OPA array to ensure that multiple OPA arrays can achieve coherent superposition in space and enhance the control ability of the far-field light field. This is an urgent problem to be solved by technical personnel in this field. Summary of the invention

[0004] In view of the limitations and shortcomings of the existing technology, this paper proposes a distributed aperture OPA array common phase system based on phase measurement chip, which achieves a significant improvement in the overall emission aperture, emission power and detection distance of the laser phased array in a multi-aperture collaborative coherent manner.

[0005] In order to achieve the above technical objectives, the specific technical solution adopted by the present invention is as follows: a distributed aperture OPA array common phase system based on a phase measurement chip, the system comprising

[0006] The optical fiber beam splitter is used to split the laser into two paths, one is the main laser path and the other is the reference light path; the main laser path is further divided into N sub-beams;

[0007] A fiber-waveguide coupler for receiving the corresponding sub-beams and transmitting them to the integrated optical chip;

[0008] An integrated optical chip includes an on-chip phase modulator and an asymmetric MMI connected in sequence, and an OPA module and an on-chip photodetector connected simultaneously and asymmetric to the MMI; after each sub-beam reaches the OPA module, a back-reflected light is generated, which is transmitted to the phase discrimination twin chip to interfere with the reference light;

[0009] The phase discrimination twin chip includes an on-chip beam splitter, an on-chip photodetector and an on-chip phase modulator. The on-chip photodetector receives interference light after the back-reflected light interferes with the reference light. The on-chip beam splitter receives the reference light and divides it into N sub-beams, which are respectively coupled to the integrated optical chip through the fiber-waveguide coupler after passing through the on-chip phase modulator, and interfere with the sub-beams corresponding to the main laser optical path in the asymmetric MMI. The interference light is received by the on-chip photodetector of the integrated optical chip.

[0010] The phase measurement compensation module is used to load the modulated signal to the on-chip phase modulator on the phase discrimination twin chip, obtain the phase error based on the electrical signal output by the on-chip photodetector of the phase discrimination twin chip, generate the corresponding control signal and load it into the on-chip phase modulator on the integrated optical chip to compensate for the dynamic phase error between the non-common optical paths of the main laser path and realize phase locking between each sub-optical path.

[0011] Furthermore, the main laser is amplified by a fiber amplifier before being divided into N sub-beams.

[0012] Furthermore, each sub-beam of the main laser enters the OPA module through asymmetric MMI coupling, most of which are emitted into the free space through the OPA module, and a small part generates back-reflected light, which is transmitted backward through the asymmetric MMI to the phase discrimination twin chip.

[0013] Furthermore, the phase measurement compensation module loads the modulation signal to the on-chip phase modulator on the phase discrimination twin chip, and the generated interference light intensity is output to the on-chip photodetector to generate a corresponding electrical signal, and the phase error is obtained according to the intensity inversion algorithm.

[0014] Furthermore, the phase measurement compensation module compensates for the dynamic phase error between the non-common optical paths of the main laser path, thereby achieving phase locking between two adjacent sub-optical paths of the main laser path, and further achieving phase locking of all sub-beams.

[0015] Furthermore, the laser is output by a laser generating device, and the laser generating device, optical fiber beam splitter, and optical fiber amplifier are all optical fiber devices, which are connected to each other by optical fiber fusion splicing; the phase identification twin chip and integrated optical chip are both thin-film lithium niobate chips, which are connected to the phase measurement compensation module, optical fiber beam splitter, and optical fiber amplifier by an optical fiber-waveguide coupler; the on-chip photodetector and the phase measurement compensation chip are electrically connected.

[0016] Furthermore, the response bandwidth of the on-chip photodetector is greater than the highest frequency of the control signal output by the phase measurement compensation module, and the optical response band covers the wavelength of the emitted laser.

[0017] Furthermore, the phase measurement and compensation module uses an FPGA-based data acquisition card to receive the electrical signal transmitted from the on-chip photodetector of the phase identification twin chip, and generates a corresponding phase control signal to transmit to the on-chip phase modulator of the integrated optical chip; the phase measurement and compensation module calculates the phase error of the corresponding sub-optical path by using an intensity inversion algorithm for the interference signal of the on-chip photodetector of the phase identification twin chip; the phase measurement and compensation module uses a PID control algorithm, a jitter method, a particle swarm algorithm, an optimized Harmant sensor algorithm or an SPGD algorithm. The phase measurement and compensation module locks the phase between adjacent sub-optical paths of the main laser optical path to a fixed phase, thereby achieving phase locking of N sub-beams.

[0018] Furthermore, the N sub-beams in the main laser optical path correspond one-to-one to the N sub-beams on the phase discrimination twin chip, and form interference pairs in pairs, which interfere in the asymmetric MMI of the integrated optical chip. The interference signal is received by the corresponding on-chip photodetector in the integrated optical chip, which is called the forward interference signal; the backward reflected light generated in the OPA chip module is transmitted backward through the MMI, and returns to the phase discrimination twin chip through the N sub-beam optical paths on the phase discrimination twin chip, and interferes with the reference light entering the phase discrimination twin chip. The interference light is received by the on-chip photodetector of the phase discrimination twin chip, which is called the backward interference signal; the phase measurement compensation module obtains the phase error of the corresponding optical path by measuring and calculating the forward interference signal and the backward interference signal.

[0019] Furthermore, the reference light is input into the phase discrimination twin chip through the mode spot converter SSC, and is divided into four paths through a cascaded multimode interferometer and then enters the on-chip modulator. After the reference light is modulated, it enters a Mach-Zehnder MZI device through the multimode interferometer, is divided into two beams through the MZI, and the output ratio of the two beams is controlled by the MZI, thereby realizing the required interference reference light power control; the backward reflected light of the main laser optical path is transmitted to the phase discrimination twin chip by the optical fiber link, and is coupled to the phase discrimination twin chip through the SSC, and is divided into two beams in the multimode interferometer for output, forming interference with the modulated reference light in the multimode interferometer, and output to the on-chip photodetector, and the on-chip photodetector outputs the interference signal to the phase measurement compensation module for measurement and calculation, thereby realizing the inversion of backward phase measurement; through the same structure, the inversion of N-path backward phase measurement is realized, thereby realizing the common phase error measurement of N-path OPA.

[0020] Beneficial effects of the invention: The present invention proposes a distributed aperture OPA array co-phase transceiver system based on a phase measurement chip, which can effectively solve the problem of insufficient power of a single OPA in long-distance detection and communication. Through the collaborative work of multi-aperture OPA arrays, the overall emission aperture, emission power and detection distance of the laser phased array are significantly improved. The present invention innovatively introduces a distributed aperture co-phase synthesis technology based on a phase discrimination twin module, realizes the coherent collaborative control of multi-aperture OPAs, and ensures that each array unit achieves coherent superposition in space, thereby enhancing the regulation capability of the far-field light field. The system breaks through the bottleneck of coherent collaboration technology of multi-OPA arrays by regulating the on-chip multi-beam light field, proposes and verifies the intra-waveguide laser beam phase detection and on-chip lithium niobate phase modulation compensation technology, and solves the phase difference measurement and correction problem of the non-common optical path OPA main laser beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0022] Figure 1 The composition and principle diagram of Example 1.

[0023] Figure 2 Schematic diagram of the multi-aperture OPA array emission structure in the embodiment.

[0024] Figure 3 Schematic diagram of the phase measurement principle in Example 1.

[0025] Figure 4 It is a flow chart of realizing non-common optical path phase locking of the main laser path based on the four-step phase shifting method and PID control algorithm in the embodiment.

[0026] Figure 5 Schematic diagram of the principle of the phase discrimination twin chip in the embodiment.

[0027] Figure 1 Description of the winning bid:

[0028] 1. Laser generating device; 2. Fiber beam splitter 3. Fiber amplifier; 4. Fiber-waveguide coupler; 5. On-chip phase modulator; 6. Asymmetric MMI; 7. OPA module; 8. On-chip photodetector; 9-11. First on-chip beam splitter - third on-chip beam splitter; 12. Phase measurement compensation module;

[0029] Figure 5 Description of the winning bid:

[0030] 100-112, the first spot mode converter SSC-the thirteenth spot mode converter SSC; 200-216, the first multi-mode interferometer MMI-the seventeenth multi-mode interferometer MMI; 300-307, the first on-chip phase shifter-the eighth on-chip phase shifter; 400-403, the first photodetector-the fourth photodetector. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0033] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0034] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, a physical connection, or a wireless communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0036] Reference Figure 1 , this embodiment provides a distributed aperture OPA array common phase system based on a phase measurement chip, including a laser generating device 1, an optical fiber beam splitter 2, an optical fiber amplifier 3, an optical fiber-waveguide coupler 4, an on-chip phase modulator 5, an asymmetric MMI 6, an OPA module 7, an on-chip photodetector 8, a first on-chip beam splitter 9, a second on-chip beam splitter 10, a third on-chip beam splitter 11 and a phase measurement compensation module 12;

[0037] The output pigtail of the laser generating device 1 is connected to the optical fiber splitter 2 and is divided into two paths. Figure 1 The one in the middle upper position is called the main laser light path. It passes through the fiber amplifier 3 and enters the fiber beam splitter, and is evenly divided into two sub-beams. The sub-beams enter the integrated optical chip through the fiber-waveguide coupler 4. The sub-beams pass through the asymmetric MMI 6. Most of the beams enter the OPA module 7 and are emitted into free space. The emission structure is shown in the figure. Figure 2 shown; located Figure 1 The light beam in the middle and lower position is called the reference light. It enters the phase identification twin chip through the fiber-waveguide coupler, and is evenly divided into two sub-beams by the first on-chip beam splitter 9 and the second on-chip beam splitter 10. Both sub-beams enter the integrated optical chip, and interfere with the sub-beams of the main laser light path in the asymmetric MMI 6. The interference light is transmitted from the other output port of the MMI to the on-chip photodetector 8, which is called the forward interference signal. The two sub-beams of the main laser light path generate part of the backward reflected light in the OPA module. The two reflected lights are backward transmitted to the phase identification twin chip through the asymmetric MMI, and interfere with the reference light in the first on-chip beam splitter 9 respectively. The interference light is received by the on-chip photodetector in the phase identification twin chip through the third on-chip beam splitter 11, which is called the backward interference signal. Figure 3 As shown, the interference signals of all on-chip photodetectors are output to the phase measurement compensation module 12, and the phase error of the corresponding sub-optical path is obtained by using an orthogonal zero-difference phase measurement algorithm for the forward interference signal and the backward interference signal; the phase-locking algorithm used is a PID control algorithm, a jitter method, a particle swarm algorithm, an optimized Harmant sensor algorithm or an SPGD algorithm, and the phase measurement compensation module 12 outputs a control signal to the on-chip phase modulator of the integrated optical chip to lock the phase between the two sub-optical paths of the main laser optical path to a fixed phase.

[0038] The laser generating device, optical fiber beam splitter, and optical fiber amplifier are all optical fiber devices, and are connected to each other by optical fiber fusion splicing; the phase discrimination twin chip and integrated optical chip are thin-film lithium niobate chips, and are connected to the phase measurement compensation module, optical fiber beam splitter, and optical fiber amplifier by an optical fiber-waveguide coupler; the on-chip photodetector and the phase measurement compensation chip are electrically connected;

[0039] The on-chip phase modulator may adopt a thermally tunable silicon waveguide phase shifter based on thermo-optical phase shifting or a thin-film lithium niobate chip based on electro-optical modulation, and the modulation bandwidth is greater than the highest phase noise frequency that needs to be corrected in the common phase system.

[0040] The phase measurement compensation module 12 may adopt an FPGA signal processor, which may receive electrical signals from each on-chip photodetector 8 and generate corresponding phase control signals to transmit to the on-chip phase modulator to lock the phases of the sub-beams of the two main laser paths to be in phase.

[0041] Figure 5 The figure shows a principle schematic diagram of a phase discrimination twin chip provided by an embodiment of the present invention, including a first spot size converter SSC 100-a thirteenth spot size converter SSC112, a first multimode interferometer MMI 200-a seventeenth multimode interferometer MMI 216, a first on-chip phase shifter 300-an eighth on-chip phase shifter 307, and a first photodetector 400-a fourth photodetector 403; the reference light is input into the phase discrimination twin chip through the first spot size converter SSC 100, and is divided into four paths through the first multimode interferometer MMI 200 of the cascade structure and then enters the first on-chip phase shifter 300-a fourth on-chip phase shifter 303; taking the first path as an example, after the reference light is modulated, it enters a Mach-Zehnder MZI device through the second multimode interferometer MMI 201, and the MZI device is composed of a sixth multimode interferometer MMI 205 is composed of the tenth multimode interferometer MMI209 and the fifth on-chip phase shifter 304; it is divided into two beams by the MZI device, and the output ratio of the two beams is controlled by the MZI device, so as to realize the reference light power control required for interference; the backward reflected light of the main laser light path is transmitted to the phase discrimination twin chip by the optical fiber link, and is coupled to the phase discrimination twin chip through the second mode spot converter SSC101, and is divided into two beams of output in the second multimode interferometer MMI201, and interferes with the modulated reference light in the fourteenth multimode interferometer MMI213, and is output to the first photodetector 400, and the first photodetector 400 outputs the interference signal to the phase measurement compensation module for measurement and calculation, so as to realize the inversion of backward phase measurement; through the same structure, the inversion of N-way backward phase measurement can be realized, so as to realize the common phase error measurement of N-way OPA.

[0042] In one embodiment of the present invention, the phase difference between the two sub-beams of the main laser light path can be obtained by the following steps:

[0043] Taking the two-way OPA common phase measurement as an example, its technical principle is mainly to measure the laser through forward interferometry. , Optical Amplifier , different fiber links , , Interference Devices , Phase errors reaching the OPA chip , The reference light fiber link is measured by interfering the reference light with the OPA back-reflected light. , and the back-reflected optical fiber link , The phase errors are , , the corresponding phase expression can be obtained:

[0044]

[0045]

[0046]

[0047]

[0048] Main laser non-common optical path phase difference It can be obtained by combining the above formulas, and its expression can be expressed as follows:

[0049]

[0050] The phase error of the main laser non-common optical path is determined by combining the results of forward interferometry and backward interferometry.

[0051] In one embodiment of the present invention, the reference light path phase modulates the reference light through a thin-film lithium niobate phase modulator, and the phase error is inverted by intensity. The traditional intensity inversion phase error can be inverted and calculated by a phase shifting interference phase measurement method. According to different shifting methods, the phase shifting interference measurement methods include a fixed-step phase shifting method, an equal-step phase shifting method, and the like. In the fixed-step phase shifting method, there are three-step, four-step, and five-step phase shifting methods. In order to simplify the system and improve the data processing speed, the four-step phase shifting method is used in this embodiment.

[0052] like Figure 4 As shown, by applying four control voltages to the thin-film lithium niobate phase modulator on the phase discrimination twin chip through the phase measurement compensation module, the light intensity expression obtained by the on-chip photodetector can be obtained as follows:

[0053]

[0054]

[0055]

[0056]

[0057] The voltages applied by the phase measurement compensation module four times respectively change the phase modulator on the phase identification twin chip by 0, , , The phase of , , , They are respectively the interference light intensity detected by the on-chip photodetector after four voltages are applied to the thin-film lithium niobate phase modulator; is the relative phase of the light beam detected by the on-chip photodetector; A is the DC parameter; B is the intensity parameter;

[0058] Relative Phase We can eliminate A and B by the following formula:

[0059]

[0060] All phases required for calculating the main laser non-common optical path phase error can be obtained in the above manner, and a phase control signal is generated based on the main laser non-common optical path phase error to lock the sub-beam phases of the two main laser optical paths to be in phase.

[0061] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A distributed aperture OPA array common phase system based on a phase measurement chip, characterized in that: The system includes The optical fiber beam splitter is used to split the laser into two paths, one is the main laser path and the other is the reference light path; the main laser path is further divided into N sub-beams; A fiber-waveguide coupler for receiving the corresponding sub-beams and transmitting them to the integrated optical chip; An integrated optical chip includes an on-chip phase modulator and an asymmetric MMI connected in sequence, and an OPA module and an on-chip photodetector connected simultaneously and asymmetric to the MMI; after each sub-beam reaches the OPA module, a back-reflected light is generated, which is transmitted to the phase discrimination twin chip to interfere with the reference light; The phase discrimination twin chip includes an on-chip beam splitter, an on-chip photodetector and an on-chip phase modulator. The on-chip photodetector receives interference light after the back-reflected light interferes with the reference light. The on-chip beam splitter receives the reference light and divides it into N sub-beams, which are respectively coupled to the integrated optical chip through the fiber-waveguide coupler after passing through the on-chip phase modulator, and interfere with the sub-beams corresponding to the main laser optical path in the asymmetric MMI. The interference light is received by the on-chip photodetector of the integrated optical chip. The phase measurement compensation module is used to load the modulated signal to the on-chip phase modulator on the phase discrimination twin chip, obtain the phase error based on the electrical signal output by the on-chip photodetector of the phase discrimination twin chip, generate the corresponding control signal and load it into the on-chip phase modulator on the integrated optical chip to compensate for the dynamic phase error between the non-common optical paths of the main laser path and realize phase locking between each sub-optical path.

2. The distributed aperture OPA array common phase system based on the phase measurement chip according to claim 1 is characterized in that: The main laser is amplified by a fiber amplifier before being divided into N sub-beams.

3. The distributed aperture OPA array common phase system based on the phase measurement chip according to claim 1 is characterized in that: Each sub-beam of the main laser enters the OPA module through asymmetric MMI coupling. Most of them are emitted into the free space through the OPA module, and a small part generates back-reflected light, which is transmitted backward through the asymmetric MMI to the phase discrimination twin chip.

4. The distributed aperture OPA array common phase system based on the phase measurement chip according to claim 1 is characterized in that: The phase measurement compensation module loads the modulated signal to the on-chip phase modulator on the phase discrimination twin chip. The generated interference light intensity is output to the on-chip photodetector to generate the corresponding electrical signal, and the phase error is obtained according to the intensity inversion algorithm.

5. The distributed aperture OPA array common phase system based on phase measurement chip according to claim 1 is characterized in that: The phase measurement compensation module compensates for the dynamic phase error between the non-common optical paths of the main laser path, realizes the phase locking between two adjacent sub-optical paths of the main laser path, and further realizes the phase locking of all sub-beams.

6. The distributed aperture OPA array common phase system based on the phase measurement chip according to claim 2 is characterized in that: The laser is output by a laser generating device. The laser generating device, optical fiber beam splitter, and optical fiber amplifier are all optical fiber devices, which are connected to each other by optical fiber fusion splicing. The phase discrimination twin chip and integrated optical chip are both thin-film lithium niobate chips, which are connected to the phase measurement compensation module, optical fiber beam splitter, and optical fiber amplifier by an optical fiber-waveguide coupler. The on-chip photodetector and the phase measurement compensation chip are electrically connected.

7. The distributed aperture OPA array common phase system based on phase measurement chip according to claim 1, characterized in that: The response bandwidth of the on-chip photodetector is greater than the highest frequency of the control signal output by the phase measurement compensation module, and the optical response band covers the wavelength of the emitted laser.

8. The distributed aperture OPA array common phase system based on phase measurement chip according to claim 1, characterized in that: The phase measurement and compensation module uses an FPGA-based data acquisition card to receive the electrical signal transmitted from the on-chip photodetector of the phase identification twin chip, and generates a corresponding phase control signal to transmit to the on-chip phase modulator of the integrated optical chip; the phase measurement and compensation module calculates the phase error of the corresponding sub-optical path by using an intensity inversion algorithm for the interference signal of the on-chip photodetector of the phase identification twin chip; the phase measurement and compensation module uses a PID control algorithm, a jitter method, a particle swarm algorithm, an optimized Harmant sensor algorithm or an SPGD algorithm. The phase measurement and compensation module locks the phase between adjacent sub-optical paths of the main laser optical path to a fixed phase, thereby achieving phase locking of N sub-beams.

9. The distributed aperture OPA array common phase system based on phase measurement chip according to claim 1, characterized in that: The N sub-beams in the main laser optical path correspond one-to-one to the N sub-beams on the phase discrimination twin chip, and form interference pairs in pairs. Interference occurs in the asymmetric MMI of the integrated optical chip, and the interference signal is received by the corresponding on-chip photodetector in the integrated optical chip, which is called the forward interference signal; the backward reflected light generated in the OPA chip module is transmitted backward through the MMI, and returns to the phase discrimination twin chip through the N sub-beam optical paths on the phase discrimination twin chip, and interferes with the reference light entering the phase discrimination twin chip. The interference light is received by the on-chip photodetector of the phase discrimination twin chip, which is called the backward interference signal; the phase measurement compensation module obtains the phase error of the corresponding optical path by measuring and calculating the forward interference signal and the backward interference signal.

10. The distributed aperture OPA array common phase system based on phase measurement chip according to claim 1, characterized in that: The reference light is input into the phase discrimination twin chip through a mode spot converter SSC, and is divided into four paths through a cascaded multimode interferometer and then enters an on-chip modulator. After the reference light is modulated, it enters a Mach-Zehnder MZI device through a multimode interferometer, is divided into two beams through the MZI, and the output ratio of the two beams is controlled by the MZI, thereby realizing the required interference reference light power control; the backward reflected light of the main laser light path is transmitted to the phase discrimination twin chip by an optical fiber link, and is coupled to the phase discrimination twin chip through an SSC, and is divided into two beams in the multimode interferometer for output, forming interference with the modulated reference light in the multimode interferometer, and output to the on-chip photodetector, and the on-chip photodetector outputs the interference signal to the phase measurement compensation module for measurement and calculation, thereby realizing the inversion of backward phase measurement; through the same structure, the inversion of N-path backward phase measurement is realized, thereby realizing the common phase error measurement of N-path OPA.

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