Light emitting device, optical chip and optical communication system

Abstract

The embodiment of the invention provides a light emitting device, an optical chip and an optical communication system, and the device comprises a light splitting module which is used for receiving an initial optical signal, carrying out the light splitting of the initial optical signal, and obtaining a first optical signal and a second optical signal; the light splitting proportion of the light splitting processing is associated with a communication mode, and the communication mode comprises a classic communication mode and a quantum communication mode; the first modulation module is used for receiving the first optical signal and modulating the first optical signal to obtain a first modulation signal; the second modulation module is used for receiving a second optical signal and modulating the second optical signal to obtain a second modulation signal; the modulation modes of the first modulation module and the second modulation module are associated with the communication mode; and the beam combining module is used for receiving the first modulation signal and the second modulation signal and combining the first modulation signal and the second modulation signal to obtain a target optical signal.

Description

Technical Field

[0001] This disclosure relates to the field of communication technology, and in particular to an optical emitting device, an optical chip, and an optical communication system. Background Technology

[0002] Quantum Key Distribution (QKD), based on fundamental principles of quantum physics, ensures the generation of symmetric secure keys by legitimate communicating parties, thereby guaranteeing the absolute security of communication information. From the perspective of the physical quantities involved in quantum state loading, QKD can be divided into two main technical routes: Discrete Variable (DV) and Continuous Variable (CV). While QKD technology is currently mature and moving towards practical application, the high cost and large size of discrete optical devices used in quantum state preparation significantly limit its widespread deployment.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] This disclosure provides an optical emitting device, an optical chip, and an optical communication system.

[0005] In a first aspect, embodiments of this disclosure provide an optical emitting device, including: a beam splitting module, a first modulation module, a second modulation module, and a beam combining module; the first modulation module and the second modulation module have the same structure; The beam splitting module is used to receive an initial optical signal and perform beam splitting processing on the initial optical signal to obtain a first optical signal and a second optical signal; the beam splitting ratio of the beam splitting processing is related to the communication mode, which includes classical communication mode and quantum communication mode; The first modulation module is used to receive the first optical signal and modulate the first optical signal to obtain a first modulated signal; the second modulation module is used to receive the second optical signal and modulate the second optical signal to obtain a second modulated signal; the modulation methods of the first modulation module and the second modulation module are associated with the communication mode. The beam combining module is used to receive the first modulation signal and the second modulation signal, and combine the first modulation signal and the second modulation signal to obtain the target optical signal.

[0006] Secondly, embodiments of this disclosure provide an optical chip, comprising: The light emitting device in the first aspect is used to receive the initial light signal and output the target light signal; An optical receiving device is used to receive target optical signals transmitted from the outside, decode the target optical signals, and obtain detection information.

[0007] Thirdly, embodiments of this disclosure provide an optical communication system, including the optical chip as described in the second aspect, the optical communication system further including: A first laser is used to emit the initial optical signal; A control module is used to control the optical chip to operate in different communication modes.

[0008] This disclosure provides an optical transmitting device, an optical chip, and an optical communication system. By controlling the splitting ratio of the beam splitting module and the modulation methods of the first and second modulation modules, the same set of hardware can be used for both classical and quantum communication. Both communication modes can be time-division multiplexed or polarization multiplexed. This reduces the hardware cost of quantum key distribution, and in the case of polarization multiplexing, the key generated in the quantum communication mode can also be used for data encryption in classical communication, enhancing the convenience of quantum encryption for classical information. Attached Figure Description

[0009] Figure 1 A schematic diagram of an optical chip provided in an embodiment of this disclosure; Figure 2 A schematic diagram of an optical communication system provided in an embodiment of this disclosure; Figure 3 This is a schematic diagram of mode conversion for a polarization rotating beam splitter provided in an embodiment of the present disclosure; Figure 4 A schematic diagram of a dynamic intensity modulation module provided in an embodiment of this disclosure; Figure 5 This is a schematic diagram of a static intensity modulation module provided in an embodiment of this disclosure. Detailed Implementation

[0010] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the disclosure. Furthermore, it should be noted that, for ease of description, only the parts relevant to the disclosure are shown in the accompanying drawings.

[0011] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing embodiments of this disclosure only and is not intended to be limiting of this disclosure.

[0012] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0013] It should be noted that the terms "first, second, third" used in the embodiments of this disclosure are merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first, second, third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this disclosure described herein can be implemented in an order other than that illustrated or described herein.

[0014] The integration of photonic chips is an essential step for the industrialization of quantum key distribution (QKD). Currently, the transmitter and receiver hardware facilities relied upon by quantum key distribution and classical information transmission are relatively independent. To achieve quantum-encrypted optical transmission devices, issues such as large space requirements and high costs exist at the optical path hardware level, hindering the large-scale commercial development of quantum-encrypted optical transmission devices. How to reduce the hardware cost of quantum key distribution and enhance the convenience of quantum encryption for classical information are problems that need to be solved.

[0015] Based on this, this disclosure provides an optical chip, including an optical emitting device and an optical receiving device. The optical emitting device includes a beam splitting module, a first modulation module, a second modulation module, and a beam combining module; the first and second modulation modules have identical structures; the beam splitting module receives an initial optical signal and performs beam splitting processing on the initial optical signal to obtain a first optical signal and a second optical signal; the beam splitting ratio is associated with a communication mode, which includes classical communication mode and quantum communication mode; the first modulation module receives the first optical signal and modulates the first optical signal to obtain a first modulated signal; the second modulation module receives the second optical signal and modulates the second optical signal to obtain a second modulated signal; the modulation methods of the first and second modulation modules are associated with the communication mode; the beam combining module receives the first and second modulated signals and combines the first and second modulated signals to obtain a target optical signal.

[0016] By controlling the splitting ratio of the beam splitting module and the modulation methods of the first and second modulation modules, the same set of hardware can be used for both classical and quantum communication. Both communication modes can be time-division multiplexed or polarization multiplexed. This reduces the hardware cost of quantum key distribution. Furthermore, in the case of polarization multiplexing, the key generated in the quantum communication mode can also be used for data encryption in classical communication, enhancing the convenience of quantum encryption for classical information.

[0017] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0018] In one embodiment of this disclosure, see [link to embodiment]. Figure 1 This illustrates a schematic diagram of an optical chip 10 provided in an embodiment of this disclosure. Figure 1 As shown, the optical chip 10 includes: The optical emitting device 20 is used to receive the initial optical signal, process the initial optical signal to obtain the target optical signal t, and output it to the outside. The optical receiver 30 is used to receive the target optical signal r transmitted from the outside, decode the target optical signal r, and obtain the detection information.

[0019] It should be noted that, in order to distinguish between the target optical signals transmitted and received by the optical chip 10, such as Figure 1 As shown, the target optical signal transmitted by the optical chip 10 to the outside is denoted as the target optical signal t, and the target optical signal received by the optical chip 10 from the outside is denoted as the target optical signal r. The target optical signal can be transmitted via optical fiber to transfer the target optical signal from one optical chip 10 to another, thereby achieving communication.

[0020] It should also be noted that the optical chip 10 can be based on silicon-based photonics, but is not limited to a silicon-based platform; for example, it can also be developed using a lithium niobate platform. This optical chip 10 is suitable for modulation and demodulation of Gaussian states in the GG02 QKD protocol.

[0021] See Figure 2 This illustration shows a schematic diagram of an optical communication system 50 including the aforementioned optical chip 10, provided by an embodiment of this disclosure. Figure 2 As shown, the optical communication system 50 also includes a first laser 501 for transmitting an initial optical signal i.

[0022] It should be noted that the first laser 501 is a device for emitting laser light sources, which can be a semiconductor laser, fiber laser, or other device or system capable of emitting pulse signals.

[0023] In some embodiments, such as Figure 2 As shown, the optical communication system 50 further includes: a first polarization controller 502, used to adjust the polarization of the initial optical signal i and then transmit it to the optical chip 10 optical emitting device 20; It should be noted that, based on the actual materials, processes, and operating modes of the internal components of the optical chip 10, and considering the reduction of transmission loss, a first polarization controller 502 can be set to adjust the polarization of the initial optical signal i, so that the initial optical signal i propagates in the optical chip 10 in a low-loss mode. Typically, the initial optical signal i is adjusted to transverse electric (TE) mode and then coupled into the optical chip 10.

[0024] In some embodiments, such as Figure 2 As shown, the optical emitting device 20 includes a beam splitting module 200, a first modulation module 201, a second modulation module 202, and a beam combining module 203; the first modulation module 201 and the second modulation module 202 have the same structure. The beam splitter module 200 is used to receive the initial optical signal i, perform beam splitting processing i on the initial optical signal i, and obtain the first optical signal i1 and the second optical signal i2; the beam splitting ratio of the beam splitting processing is related to the communication mode, which includes classical communication mode and quantum communication mode. The first modulation module 201 is used to receive the first optical signal i1 and modulate the first optical signal i1 to obtain the first modulation signal m1; the second modulation module 202 is used to receive the second optical signal i2 and modulate the second optical signal i2 to obtain the second modulation signal m2; the modulation method of the first modulation module 201 and the second modulation module 202 is associated with the communication mode. The beam combining module 203 is used to receive the first modulation signal m1 and the second modulation signal m2, and combine the first modulation signal m1 and the second modulation signal m2 to obtain the target optical signal t.

[0025] It should be noted that the components of the optical chip 10 that have interconnections can be connected through optical waveguides to transmit optical signals between different components. The optical waveguides used to connect the components are also components of the optical chip 10.

[0026] like Figure 2 As shown, the input terminal of the beam splitter 200 receives the initial optical signal i, and the first output terminal of the beam splitter 200 is connected to the input terminal of the first modulation module 201 for transmitting the first optical signal i1; the second output terminal of the beam splitter 200 is connected to the input terminal of the second modulation module 202 for transmitting the second optical signal i2; the output terminal of the first modulation module 201 is connected to the first input terminal of the beam combiner 203 for transmitting the first modulation signal m1; and the output terminal of the second modulation module 202 is connected to the second input terminal of the beam combiner 203 for transmitting the second modulation signal m2.

[0027] Before the beam splitter 200, the optical emitting device 20 may further include an input coupling module (not shown in the figure) connected to the input end of the beam splitter 200, used to couple the initial optical signal i into the beam splitter 200. After the beam combiner 203, the optical emitting device 20 may further include an output coupling module (not shown in the figure) connected to the output end of the beam combiner 203, used to couple the target optical signal t to the output. The input coupling module and the output coupling module, as end-face couplers for coupling the optical signals into and out, can both be spot size converters (SSCs). The spot size converter can optimize the transmission efficiency and mode matching of the optical signal, achieving efficient coupling by changing the shape and size of the light spot.

[0028] The optical chip 10 provided in this embodiment can realize both classical communication and quantum communication. Classical communication can include classical coherent optical communication, which uses the coherence of light to transmit data; quantum communication utilizes the quantum mechanical properties of light to achieve absolutely secure communication. Different communication modes can be achieved by adjusting the operating modes of the beam splitter 200, the first modulation module 201, and the second modulation module 202 at the transmitting end.

[0029] For the beam splitter module 200, the adjustment methods include adjusting the beam splitting ratio of the beam splitter module 200. For example, it can include a uniform beam splitting ratio and a non-uniform beam splitting ratio.

[0030] For the first modulation module 201 and the second modulation module 202, the adjustment methods include adjusting the modulation methods of the first modulation module 201 and the second modulation module 202. For example, it may include: IQ modulation, quantum state modulation (specifically, Gaussian state modulation), or no modulation, etc.

[0031] It should be noted that the multiplexing methods for classical and quantum communication modes include time-division multiplexing and polarization multiplexing. Time-division multiplexing means operating in either classical or quantum communication modes at different times; in polarization multiplexing, there is no strict time distinction between the two communication modes.

[0032] In the classic time-division multiplexing communication mode, the beam splitting ratio is 1:1; both the first modulation module 201 and the second modulation module 202 use IQ modulation. That is, the beam splitting module 200 splits the initial optical signal i at a uniform beam splitting ratio of 1:1, resulting in the output first optical signal i1 and second optical signal i2 having the same intensity, or in other words, the same optical power / energy. The first modulation module 201 processes the first optical signal i1 using the classic IQ modulation method to obtain the first modulated signal m1; the second modulation module 202 processes the second optical signal i2 using the classic IQ modulation method to obtain the second modulated signal m2. IQ modulation is a technique that splits data into two paths for carrier modulation, where I represents in-phase and Q represents quadrature.

[0033] In time-division multiplexing quantum communication mode, examples of two implementation methods are shown below, but are not limited to these.

[0034] Example 1: The beam splitting ratio in the beam splitting process is a:b, where a and b are unequal positive numbers; the lower-ratio optical signal is used for quantum state preparation, and the higher-ratio optical signal is the pilot light; in the first modulation module 201 and the second modulation module 202, one of the modules used for quantum state preparation modulates the received optical signal using quantum state modulation, while the other does not modulate the pilot light. The quantum state modulation is performed by applying a loaded random Gaussian modulated electrical signal to the received optical signal.

[0035] That is, the beam splitting module 200 performs non-uniform beam splitting on the initial optical signal i, resulting in a first optical signal i1 and a second optical signal i2, one with a stronger intensity and the other with a weaker intensity. The stronger signal serves as the pilot light, and the weaker signal is used for quantum state preparation. Assuming a:b = 10:90, the intensity ratio of the first optical signal i1 is 10, used for quantum state preparation, and the intensity ratio of the second optical signal i2 is 90, serving as the pilot light. The first modulation module 201 modulates the first optical signal i1 to the quantum state; in this embodiment, this can be Gaussian modulation. The second modulation module 202 does not modulate the second optical signal i2, which serves as the pilot light. The pilot light provides a stable reference for the quantum signal in terms of frequency, phase, time, and polarization, ensuring that both communicating parties can correctly send and receive the quantum state, but it does not carry any quantum information or key information itself.

[0036] Example 2: The beam splitting ratio is 1:1, and both the first modulation module 201 and the second modulation module 202 perform quantum state modulation based on the received optical signal.

[0037] That is, the beam splitting module 200 splits the initial optical signal i at a uniform beam splitting ratio of 1:1, and the output first optical signal i1 and second optical signal i2 have the same intensity. The first modulation module 201 performs quantum state modulation on the first optical signal i1, and the second modulation module i2 performs quantum state modulation on the second optical signal i2. The quantum state modulation is performed by using a loaded random Gaussian modulated electrical signal and a pilot signal to perform quantum state modulation on the received optical signal. In this example, both the first modulation module 201 and the second modulation module 202 are used for quantum state preparation, and the pilot signal is not obtained by splitting the initial optical signal i, but is provided externally.

[0038] In polarization multiplexing, the beam splitting ratio of the beam splitting process is c:d, where c and d are unequal positive numbers. The first modulation module 201 and the second modulation module 202 operate in classical communication mode and quantum communication mode, respectively. The one operating in quantum communication mode receives the optical signal with a lower ratio and performs quantum state modulation on the received optical signal, while the one operating in classical communication mode receives the optical signal with a higher ratio and performs IQ modulation on the received optical signal.

[0039] That is, the beam splitter module 200 performs non-uniform beam splitting on the initial optical signal i, and of the output first optical signal i1 and second optical signal i2, one has a stronger intensity and the other has a weaker intensity. The stronger signal is used for classical communication, and the weaker signal is used for quantum state preparation. The quantum state modulation method is the same as described in method 2 above.

[0040] It should also be noted that the control of the beam splitter module 200, the first modulation module 201, and the second modulation module 202 can be implemented by a control module (not shown in the figure). The optical communication system 50 may also include a control module for controlling the optical chip 10 to operate in different communication modes.

[0041] The control module can be divided into different control sub-modules, which are used to control the operation of different beam splitting modules 200, the first modulation module 201, and the second modulation module 202. For example, the control sub-module for controlling the beam splitting module 200 loads different control signals to the beam splitting module 200 to achieve different beam splitting ratios; the control sub-module for controlling the first modulation module 201 and the second modulation module 202 loads electrical signals suitable for classical communication or random Gaussian modulated electrical signals for quantum communication in different communication modes, and may also include pilot signals to achieve the corresponding communication modes.

[0042] Thus, by controlling the working modes of the beam splitting module 200, the first modulation module 201, and the second modulation module 202, this embodiment of the present disclosure realizes quantum communication and classical communication in the same optical transmitting device 20. Quantum communication can be a continuous variable quantum communication mode, which does not require separate hardware devices to implement the two communication modes, effectively saving hardware resources and facilitating the miniaturization and integration of optical chips.

[0043] In some embodiments, the beam combining module 203 is a polarization splitting rotor (PSR).

[0044] It should be noted that photons can propagate in either transverse electric (TE) or transverse magnetic (TM) modes. The TE mode corresponds to a vertical polarization state of the optical field. (Vertical polarization), the polarization state corresponding to the TM mode is horizontal polarization. (Horizontal polarization).

[0045] like Figure 3 As shown, the PSR can achieve the following functions: the transverse electric mode input in one arm is converted into a transverse magnetic mode, while the transverse electric mode input in the other arm remains unchanged at the output. That is, the beam combining module 203 can include two propagation conversion paths to realize the conversion between TE mode propagation and TM mode propagation, and realize the rotational beam combining of the first modulation signal m1 and the second modulation signal m2.

[0046] The upper and lower arms of the beam combining module 203 are connected to the first modulation module 201 and the second modulation module 202, respectively. One arm includes a TE→TE conversion path, and the other arm includes a TE→TM conversion path. On both propagation conversion paths, the light energy loss in the "TE→TM" path is greater than that in the "TE→TE" path. Therefore, the ratio of the horizontal polarization component to the vertical polarization component in the target optical signal t may not meet the requirements for fabrication due to this light energy loss. Furthermore, although the first modulation module 201 and the second modulation module 202 have the same structure, the light signal loss in the first modulation module 201 and the second modulation module 202 may differ due to practical factors such as fabrication process and material limitations.

[0047] Therefore, in order to balance the loss difference between the upper and lower arms of the beam combining module 203, in some embodiments, such as Figure 2 As shown, the light emitting device 20 may further include: a first adjustable attenuation module 204 and a second adjustable attenuation module 205; wherein: The first adjustable attenuation module 204 is connected between the output of the first modulation module 201 and the first input of the beam combining module 203. The second adjustable attenuation module 205 is connected between the output of the second modulation module 202 and the second input of the beam combining module 203. The attenuation of the received optical signal by the first adjustable attenuation module 204 and the second adjustable attenuation module 205 meets the attenuation requirements of the communication mode.

[0048] It should be noted that, as Figure 2 As shown, the first adjustable attenuation module 204 and the second adjustable attenuation module 205 can be used to attenuate the optical signals output by the first modulation module 201 and the second modulation module 202 to compensate for the loss difference between the two paths.

[0049] It should also be noted that the required attenuation may differ under different communication modes, requiring adjustment based on the specific communication mode. Therefore, both the first adjustable attenuation module 204 and the second adjustable attenuation module 205 are dynamic attenuation modules, meaning the attenuation is variable rather than fixed. The first adjustable attenuation module 204 and the second adjustable attenuation module 205 can be variable optical attenuators (VOAs) or other structures capable of achieving optical attenuation.

[0050] The control module may also include a control submodule for controlling the attenuation amount of the first adjustable attenuation module 204 and the second adjustable attenuation module 205, so as to perform attenuation control separately under different attenuation requirements.

[0051] In practical applications, only one of the two adjustable attenuation modules may be in attenuation mode, attenuating the received optical signal while the other remains unaffected. For example, if the optical path loss of the upper arm (the arm connecting to the first modulation module 201) of the beam combiner module 203 is less than that of the lower arm (the arm connecting to the second modulation module 202), then only the optical signal in the path of the upper arm needs to be attenuated to match the loss of the lower arm, while the lower arm does not require attenuation, thus balancing the optical losses of the two paths.

[0052] In some embodiments, the beam combining module 203 can be a two-dimensional grating coupler (2D-GC). The two-dimensional grating coupler can simultaneously realize the beam combining and coupling output of optical signals without the need to set up a coupling output module.

[0053] At the receiving end, such as Figure 2 As shown, the optical receiving device 30 includes: The polarization beam splitter module 301 is used to receive the target optical signal r sent from the outside, split the target optical signal r into beams, and obtain the first beam splitter signal b1 and the second beam splitter signal b2. The optical path of the polarization beam splitter module 301 is the same as and the reverse of the optical path of the beam combining module 203 that synthesizes the target optical signal. The second beam splitter 302 is used to receive the local oscillator light l and split the local oscillator light l to obtain the first local oscillator light l1 and the second local oscillator light l2. The third beam splitter 303 is used to receive the first beam splitting signal b1 and the first local oscillator light l1, and output two optical components after interference (referred to as optical component a1 and optical component a2 respectively). The fourth beam splitter 304 is used to receive the second beam splitting signal b2 and the second local oscillator light l2, and output two optical components after interference (denoted as optical component a3 and optical component a4 respectively). The detection module 305 is used to detect the optical components output by the third beam splitter 303 and the fourth beam splitter 304, and output detection information.

[0054] It should be noted that the polarization beam splitter module 301 and the beam combiner module 203 have the same structure, but opposite optical paths, and their inputs and outputs are interchanged. For example... Figure 3 As shown, the polarization beam splitter module 301 is also a PSR. When used as a beam combiner, the PSR includes two input terminals and one output terminal; when used as a beam splitter, the PSR includes one input terminal and two output terminals.

[0055] In this way, the polarization beam splitting module 301 can split the received target optical signal and restore its state before synthesis. That is, assuming that the target optical signal t and the target optical signal r are the same optical signal, then the first beam splitting signal b1 and the second beam splitting signal b2 are the first modulation signal m1 and the second modulation signal m2.

[0056] In some embodiments, such as Figure 2 As shown, the optical communication system 50 also includes a second polarization controller 503, which is used to adjust the polarization of the target optical signal r received by the optical chip 10 and then transmit it to the optical receiving device 30 of the optical chip 10.

[0057] It should be noted that at the receiving end, the optical chip 10 receives the target optical signal r transmitted from the outside. After long-distance transmission, the polarization state of the target optical signal r may change; for example, some TE modes may be converted to TM modes. Therefore, in this embodiment, a second polarization controller 503 can be provided before the optical receiving device 30 to adjust the polarization of the target optical signal r, compensate for the polarization state change of the target optical signal r during transmission, and then transmit it to the optical receiving device 30.

[0058] In some embodiments, such as Figure 2As shown, the optical communication system 50 also includes a second laser 504 for emitting local oscillator light 1.

[0059] It should be noted that the second beam splitter 302, the third beam splitter 303, and the fourth beam splitter 304 can all be 1:1 multimode interferometers (1:1 MMIs). Among them, the second beam splitter 302 is a single-input dual-output 1:1 MMI, while the third beam splitter 303 and the fourth beam splitter 304 are dual-input dual-output 1:1 MMIs.

[0060] In some embodiments, such as Figure 2 As shown, the detection module 305 includes a first detector 3051, a second detector 3052, a third detector 3053, and a fourth detector 3054. The first detector 3051 and the second detector 3052 form one set of balanced detectors, while the third detector 3053 and the fourth detector 3054 form another set of balanced detectors. Each set of balanced detectors can use an on-chip differential method to output a differential photocurrent signal, which is converted into a voltage signal by a single-ended transimpedance amplifier and then acquired by an analog-to-digital converter for data analysis and processing. Alternatively, each set of balanced detectors can output its own photocurrent signal, which is differentially amplified by a dual-ended transimpedance amplifier and then acquired by an analog-to-digital converter for data analysis and processing. The amplifier and analog-to-digital converter can be off-chip devices independent of the optical chip 10.

[0061] In some embodiments, such as Figure 2 As shown, the optical receiving device 30 may further include: The compensation module 306 is used to compensate for the difference in optical components output by the third beam splitter 303 and the fourth beam splitter 304.

[0062] It should be noted that this embodiment also includes a compensation module 306 to compensate for potential splitting unevenness risks that may exist in the 1:1 MMI (third beam splitter 303 and fourth beam splitter 304). For example, splitting unevenness caused by actual process.

[0063] like Figure 2 As shown, the compensation module 306 may include: a first attenuator 3061, a second attenuator 3062, a third attenuator 3063, and a fourth attenuator 3064. The input terminal of the first attenuator 3061 is connected to the first output terminal of the third beam splitter 303; the input terminal of the second attenuator 3062 is connected to the second output terminal of the third beam splitter 303; the input terminal of the third attenuator 3063 is connected to the first output terminal of the fourth beam splitter 304; and the input terminal of the fourth attenuator 3064 is connected to the second output terminal of the fourth beam splitter 304.

[0064] The first attenuator 3061 and the second attenuator 3062 form an attenuator group to compensate for potential beam splitting unevenness in the third beam splitter 303. This unevenness is usually a fixed non-uniformity caused by the device itself. Therefore, the first attenuator 3061 and the second attenuator 3062 can serve as a static intensity modulation module to achieve a fixed attenuation amount. Typically, one of the first attenuator 3061 and the second attenuator 3062 performs optical attenuation, while the other is used to balance the optical path length of the two optical components. For example, if the intensity of optical component a1 is greater than that of optical component a2 due to the third beam splitter 303 itself, resulting in non-uniform beam splitting, then the first attenuator 3061 attenuates optical component a1 to make its intensity the same as that of optical component a2, while the second attenuator 3062 does not attenuate optical component a2 but is only used to balance the optical path length.

[0065] The third attenuator 3063 and the fourth attenuator 3064 form another attenuator group, used to compensate for possible beam splitting unevenness in the fourth beam splitter 304. Their implementation principle is the same as that of the first attenuator 3061 and the second attenuator 3062, and will not be repeated here.

[0066] Thus, in cases where the actual beam splitting ratio does not reach the expected 1:1 splitting ratio due to process errors during chip manufacturing, this embodiment utilizes compensation module 306 to achieve compensation. If the original beam splitting effect is already excellent, there is no need to activate each attenuator for compensation; the optical signal can pass directly through the attenuators without attenuation.

[0067] The first detector 3051 detects the optical signal output by the first attenuator 3061, the second detector 3052 detects the optical signal output by the second attenuator 3062, the third detector 3053 detects the optical signal output by the third attenuator 3063, and the fourth detector 3054 detects the optical signal output by the fourth attenuator 3064.

[0068] The following describes the more specific internal structure of the optical transmitter 20 and the optical receiver 30.

[0069] like Figure 2 As shown, the first modulation module 201 and the second modulation module 202 have the same structure and may include: The first beam splitter 2011 is used to split the received optical signal into a first optical component and a second optical component. The first intensity modulation module 2012 is used to modulate the intensity of the first optical component to obtain the third optical component; The second intensity modulation module 2013 is used to modulate the intensity of the second optical component to obtain the fourth optical component; The first phase shifter 2014 is used to shift the phase of the third optical component to obtain the fifth optical component; The second phase shifter 2015 is used to shift the phase of the fourth optical component to obtain the sixth optical component; The first beam combiner 2016 combines the fifth and sixth optical components to obtain the output optical signal.

[0070] It should be noted that both the first beam splitter 2011 and the first beam combiner 2016 can be 1:1 MMIs. When used as beam splitters, 1:1 MMIs can equally divide the input light into two parts, with each part outputting 50% of the power, and their optical paths are reversible. When used as beam combiners, they coherently combine the two input optical signals into one output optical signal.

[0071] like Figure 2 As shown, the first modulation module 201 and the second modulation module 202 can both be Mach Zehnder interferometers (MZI). The input optical signal is split, intensity modulated, phase shifted, and combined to obtain the output optical signal.

[0072] It should also be noted that, to satisfy both classical and quantum communication modes, the first intensity modulation module 2012 and the second intensity modulation module 2013 are both dynamic intensity modulation modules with variable modulation methods. Simultaneously, the beam splitting module 2011, the first adjustable attenuation module 204, and the second adjustable attenuation module 205 can be implemented using the same dynamic intensity modulation module, achieving different functions by changing the state of the applied electrical signal. See [link to relevant documentation] Figure 4 The diagram shows a schematic of the dynamic intensity module provided in the embodiments of the present disclosure, wherein (a) is a single-input dual-output dynamic intensity module, which can be used as a beam splitting module 200, and (b) is a single-input single-output dynamic intensity module, which can be used as a first intensity modulation module 2012, a second intensity modulation module 2013, a first adjustable attenuation module 204, and a second adjustable attenuation module 205.

[0073] like Figure 4 As shown, the dynamic intensity modulation module may include: First multimode interference coupler 401, third phase shifter 402, fourth phase shifter 403, fifth phase shifter 404, sixth phase shifter 405, second multimode interference coupler 406; The first multimode interference coupler 401 is a single-input dual-output type, and the second multimode interference coupler is a dual-input single-output type; the third phase shifter 402 and the fourth phase shifter 403 are high-speed phase shifters, and the fifth phase shifter 404 and the sixth phase shifter 405 are low-speed phase shifters; the high-speed phase shifters operate in different communication modes based on different applied electrical signals; The third phase shifter 402 and the fifth phase shifter 404 are connected between the first output terminal of the first multimode interference coupler 401 and the first input terminal of the second multimode interference coupler 406. The fourth phase shifter 403 and the sixth phase shifter 405 are connected between the second output terminal of the first multimode interference coupler 401 and the second input terminal of the second multimode interference coupler 406.

[0074] It should be noted that, as Figure 4 As shown, the intensity modulation mode of the dynamic intensity modulation module is variable, thereby realizing different types of modulation.

[0075] In the dynamic intensity modulation module, the various structures can be connected and signal transmitted through optical waveguides. The optical signal entering through the input end of the first multimode interference coupler 401 is divided into two parts by the first multimode interference coupler 401 and transmitted to the third phase shifter 402 and the fourth phase shifter 403 respectively.

[0076] Both the third and fourth phase shifters 402 are high-speed phase shifters, such as carrier depletion modulators (CDMs). A CDM is a typical radio frequency modulation phase shifter with modulation rates reaching tens of GHz. CDMs alter the phase or intensity of optical signals by controlling the carrier concentration distribution within the waveguide using an electric field. By applying different electrical signals to the high-speed phase shifters, different modulation schemes can be achieved to meet the modulation requirements of different communication modes. In this embodiment, the control module can apply electrical signals to the high-speed phase shifters. The third and fourth phase shifters 402 and 403 modulate the received optical signals based on the applied electrical signals and then output the modulated signals to the fifth and sixth phase shifters 404 and 405.

[0077] The fifth phase shifter 404 and the sixth phase shifter 405 are low-speed phase shifters, such as thermo-optical phase shifters (TOPS). The phase shift amounts of the fifth phase shifter 404 and the sixth phase shifter 405 are fixed values ​​set after pre-adjustment, enabling carrier-suppressed single-sideband modulation. During the operation of the dynamic intensity modulation module, the static operating point of the Mach-Zehnder interferometer can be adjusted by the low-speed phase shifters to keep the MZI in the optimal linear operating region for intensity modulation. The optical signals output from the fifth phase shifter 404 and the sixth phase shifter 405 are combined by the second multimode interference coupler 406.

[0078] In this configuration, both the first multimode interference coupler 401 and the second multimode interference coupler 406 can be 1:1 MMIs. For example... Figure 4As shown, when the dynamic intensity modulation module is used as the beam splitting module 200, the second multimode interference coupler 406 is a dual-input dual-output module; when the dynamic intensity modulation module is used as the first intensity modulation module 2012, the second intensity modulation module 2013, the first adjustable attenuation module 204, and the second adjustable attenuation module 205, the second multimode interference coupler 406 is a single-input single-output module.

[0079] At the receiving end, the first attenuator 3061 to the fourth attenuator 3064 are static intensity modulation modules, meaning the attenuation is a fixed value. The first attenuator 3061 to the fourth attenuator 3064 can be a VOA, or as... Figure 5 The structure shown includes: a third multimode interference coupler 701, a seventh phase shifter 702, an eighth phase shifter 703, and a fourth multimode interference coupler 704.

[0080] The input terminal of the third multimode interference coupler 701 is used to receive the corresponding optical component. The first output terminal of the third multimode interference coupler 701 is connected to the input terminal of the seventh phase shifter 702. The second output terminal of the third multimode interference coupler is connected to the input terminal of the eighth phase shifter 703. The output terminal of the seventh phase shifter 702 is connected to the first input terminal of the fourth multimode interference coupler 704. The output terminal of the eighth phase shifter 703 is connected to the second input terminal of the fourth multimode interference coupler 704. The output terminal of the fourth multimode interference coupler 704 outputs the attenuated optical component.

[0081] The third and fourth multimode interference couplers 701 and 704 can be 1:1 MMIs. The seventh and eighth phase shifters 702 and 703 are both low-speed phase shifters, such as TOPS. One or both of them shift the phase of the corresponding optical components to create a phase difference between the two optical components. After interference by the fourth multimode interference coupler 704, the optical components are attenuated. If attenuation is not required, the seventh and eighth phase shifters 702 and 703 either do not perform phase shifting or perform the same phase shift.

[0082] In the embodiments disclosed herein, all dynamic intensity modulation modules are radio frequency driven, and more specifically, the high-speed phase shifters in the dynamic intensity modulation modules are radio frequency driven. By changing the electrical signal applied to the high-speed phase shifters through the control module, optical signal preparation in different states and phase shifting or attenuation of different degrees can be achieved. All static intensity modulation modules are DC driven, and more specifically, the low-speed phase shifters are DC driven. The first phase shifter 2014 and the second phase shifter 2015 are also low-speed phase shifters driven by DC, such as TOPS. Each beam splitter and beam combiner (MMI or PSR) achieves beam combining and beam splitting through its own specific structure without the need for external driving.

[0083] like Figure 2As shown, the first modulation module 201 and the second modulation module 202 are IQ modulators, and the detector in the detection module is a coherent detector. This embodiment of the present disclosure implements a hardware-based, duplex or simplex optical path for continuous-variable quantum key distribution and classical coherent optical communication, based on IQ modulators and coherent detectors.

[0084] The following is combined Figures 2-5 The operation of the optical chip 10 under different communication modes is illustrated by example.

[0085] In classic communication mode: The first laser 501 emits continuous light (e.g., narrow-linewidth continuous light) as the initial optical signal injected into the optical chip 10. The first polarization controller 502 adjusts the initial optical signal i to TE mode. The beam splitter 200 is modulated to have the same output optical power, i.e., a beam splitting ratio of 1:1. The transmission processing path where the first modulation module 201 is located is denoted as the X branch, and the transmission processing path where the second modulation module 202 is located is denoted as the Y branch. Both the first modulation module 201 and the second modulation module 202 perform IQ modulation, with the upper arm being the I path and the lower arm being the Q path. The I path of the X branch is denoted as the XI path, and the Q path of the X branch is denoted as the XQ path; the I path of the Y branch is denoted as the YI path, and the Q path of the Y branch is denoted as the YQ path.

[0086] The first adjustable attenuation module 204 and the second adjustable attenuation module 205 are used for static intensity modulation, that is, to perform a fixed amount of attenuation to balance the inherent structural losses of the X and Y branches, such as the loss difference between the upper and lower arms connected by the beam combiner module 203. Here, a coherent communication signal modulation format is used to realize classic signal transmission based on this chip architecture.

[0087] In quantum communication, depending on different Gaussian state modulation and demodulation methods, the ways to realize continuous variable QKD (CV-QKD) include, but are not limited to, the following two: Method 1: The first laser 501 emits narrow-linewidth continuous light as the initial optical signal i. The initial optical signal i is adjusted by the first polarization controller 502 and coupled into the optical chip 10 in TE mode. The splitting ratio of the beam splitting module 200 is adjusted to an unbalanced state, for example, 10:90. 90% of the light (the second optical signal i2) enters the lower splitter (Y branch) as pilot light, used as a reference to recover the phase change of the quantum signal at the detector end; 10% of the light (the first optical signal i1) enters the upper splitter (X branch) for Gaussian state modulation.

[0088] The pilot light enters the second modulation module 202 through the lower branch. The second modulation module 202 is an MZI. In this MZI, the first intensity modulation module 2012, the second intensity modulation module 2013, the first phase shifter 2014, and the second phase shifter 2015 do not perform any modulation. At this time, the phase difference between the YI and YQ arms is 0, and 90% of the optical signal intensity remains unchanged during output.

[0089] 10% of the optical signal enters the same MZI structure in the upper branch. In order to achieve Gaussian modulation QKD, the high-speed phase shifters (i.e., the third phase shifter 402 and the fourth phase shifter 403) in the XI and XQ paths achieve Gaussian modulation by loading random Gaussian modulation electrical signals. The first phase shifter 2014 and the second phase shifter 2015 are adjusted in the XI and XQ paths respectively to achieve carrier-suppressed single-sideband modulation. The phase shift amount of the first phase shifter 2014 and the second phase shifter 2015 is a pre-tuned phase shift amount that can achieve carrier-suppressed single-sideband modulation.

[0090] The first adjustable attenuation module 204 and the second adjustable attenuation module 205 are used for static intensity modulation to achieve a fixed attenuation amount. For example, only the low-speed phase shifter can be adjusted to attenuate the quantum signal intensity and the pilot signal, respectively, until the QKD system meets the optimal secure key generation conditions.

[0091] The quantum signal light and the pilot signal light are combined by the beam combiner module 203 to obtain the target optical signal t, which is then coupled into the optical fiber link and transmitted to the outside.

[0092] At the receiving end, the received target optical signal r is adjusted by the second polarization controller 503 so that the quantum signal light and the pilot light can be precisely separated by the polarization beam splitting module 301. The local oscillator light l is split into two parts by the second beam splitter 302, and beats with the quantum signal light and the pilot light respectively at two adjacent 1:1 beam splitters (i.e., the third beam splitter 303 and the fourth beam splitter 304), and is finally detected by the photodetector (i.e., the detection module 305). The above detection process depends on whether the frequency of the local oscillator light used is the same as or different from that of the laser used at the transmitting end (i.e., the first laser 501). If they are the same, it is a zero-difference balanced detection; if they are different, it is a heterodyne balanced detection. The first attenuator 3061 to the fourth attenuator 3064 are used to compensate for the potential risk of beam splitting unevenness of the third beam splitter 303 and the fourth beam splitter 304.

[0093] The output photocurrents of the two pairs of balanced detectors are differentially amplified, then acquired and quantized by an analog-to-digital converter. Finally, quantum key extraction is performed through post-processing.

[0094] Method 2: The first laser 501 inputs narrow-linewidth continuous light as the initial optical signal i, which is then adjusted by the first polarization controller 502 to couple the TE mode optical signal into the optical chip 10.

[0095] The splitting ratio of the beam splitter module 200 is adjusted to a balanced state, i.e., 1:1. Gaussian modulation is performed on the upper and lower paths respectively. By adjusting the low-speed phase shifters in the four paths XI, XQ, YI, and YQ, the IQ modulators in the X and Y dimensions are put into carrier-suppressed single-sideband modulation state. Random Gaussian modulated electrical signals and pilot signals are applied to the high-speed modulators in the two dimensions respectively to realize quantum state preparation.

[0096] At the receiving end, the modulated quantum signals in the two orthogonal polarization dimensions X and Y simultaneously contain pilot signals. After polarization adjustment by the second polarization controller 503, the polarization beam splitter module 301 separates the X and Y signals, which then enter two sets of balanced detectors. The local oscillator light uses narrow-linewidth continuous light, with the same frequency as or a certain frequency offset from the first laser source 501 at the transmitting end. It passes through the second to fourth beam splitters 302 and enters the two sets of balanced detectors, where it undergoes null-difference or heterodyne balanced detection with the modulated signals of the X and Y paths. The output photocurrents of the two pairs of balanced detectors are differentially amplified, then acquired and quantized by an analog-to-digital converter. Finally, quantum key extraction is performed through post-processing.

[0097] Compared to method 1, in method 2, since quantum state preparation is performed simultaneously on both paths, the efficiency of key generation is improved at the same quantum state modulation frequency.

[0098] In short, the optical chip 10 and its associated optical communication system 50 support both quantum key distribution and classical information encoding / decoding. Time-division multiplexing can be used to allow the chip to operate in either quantum or classical mode. Polarization multiplexing can also be used to allow the chip to support both quantum and classical modes simultaneously. The generated quantum key can be used for classical information encryption.

[0099] In the co-operation mode of classical information encoding (i.e., classical communication) and quantum key distribution (i.e., quantum communication), during time-division multiplexing, the high-speed modulator in the beam splitting module 200 can switch the beam splitting ratio to meet the optimal optical intensity required for both QKD and classical coherent communication. Typically, in the classical coherent optical communication mode, the X and Y beam intensity ratio needs to be adjusted to 1:1. At this time, the first adjustable attenuation module 204 and the second adjustable attenuation module 205 operate at their maximum output power points, for example, with an attenuation of 0, ensuring that the emitted coherent modulated signal is strong enough for long-distance information transmission. In the QKD mode (i.e., quantum communication mode), the output ratio of the beam splitting module 200 is adjusted according to the selected method, such as the aforementioned method 1 and method 2. The first adjustable attenuation module 204 and the second adjustable attenuation module 205 are used to further adjust the intensity of the quantum signal or pilot signal to achieve optimal quantum key distribution conditions.

[0100] In polarization multiplexing, the beam splitter 200 is adjusted to an appropriate splitting ratio, typically non-uniform splitting, to ensure that the optical signal intensity in the classical coherent communication dimension is greater than that in the quantum communication dimension. Then, according to the modulation requirements of quantum and classical signals, the two dimensions are modulated separately. Finally, at the receiving end, the optical signals of the two polarization dimensions are separated and each signal is demodulated by a pair of balanced detectors.

[0101] In summary, the present disclosure provides an optical chip 10, an optical communication system 50 to which the optical chip 10 belongs, and an optical transmitter 20 and an optical receiver 30 included in the optical chip 10. A single chip hardware set supports both quantum key distribution and classical information encoding and decoding, which can greatly save the cost of optical signal modulation and demodulation.

[0102] The above description is merely a preferred embodiment of this disclosure and is not intended to limit the scope of protection of this disclosure.

[0103] It should be noted that, in this disclosure, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0104] The sequence numbers of the embodiments disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0105] The methods disclosed in the several method embodiments provided in this disclosure can be arbitrarily combined without conflict to obtain new method embodiments.

[0106] The features disclosed in the several product embodiments provided in this disclosure can be arbitrarily combined without conflict to obtain new product embodiments.

[0107] The features disclosed in the several method or device embodiments provided in this disclosure can be arbitrarily combined without conflict to obtain new method or device embodiments.

[0108] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A light emitting device, characterized in that, include: The system comprises a beam splitting module, a first modulation module, a second modulation module, and a beam combining module; the first modulation module and the second modulation module have the same structure. The beam splitting module is used to receive an initial optical signal and perform beam splitting processing on the initial optical signal to obtain a first optical signal and a second optical signal; the beam splitting ratio of the beam splitting processing is related to the communication mode, which includes classical communication mode and quantum communication mode; The first modulation module is used to receive the first optical signal and modulate the first optical signal to obtain a first modulation signal; The second modulation module is used to receive the second optical signal and modulate the second optical signal to obtain a second modulated signal; the modulation methods of the first modulation module and the second modulation module are associated with the communication mode. The beam combining module is used to receive the first modulation signal and the second modulation signal, and combine the first modulation signal and the second modulation signal to obtain the target optical signal.

2. The light emitting device according to claim 1, characterized in that, The multiplexing methods of the classical communication mode and the quantum communication mode include: time division multiplexing and polarization multiplexing.

3. The light emitting device according to claim 2, characterized in that, In the classic time-division multiplexing communication mode, the beam splitting ratio of the beam splitting process is 1:1; the modulation methods of the first modulation module and the second modulation module are both IQ modulation; In the time-division multiplexing quantum communication mode, the beam splitting ratio of the beam splitting process is a:b, where a and b are unequal positive numbers; wherein, the optical signal with the lower ratio is used for quantum state preparation, and the optical signal with the higher ratio is the pilot light; in the first modulation module and the second modulation module, one of the modules used for quantum state preparation modulates the received optical signal with quantum state, while the other does not modulate the pilot light; or, the beam splitting ratio of the beam splitting process is 1:1, and both the first modulation module and the second modulation module modulate the received optical signal with quantum state. In the polarization multiplexing, the beam splitting ratio of the beam splitting process is c:d, where c and d are unequal positive numbers. The first modulation module and the second modulation module operate in the classical communication mode and the quantum communication mode, respectively. The module operating in the quantum communication mode receives the optical signal with a lower ratio and performs quantum state modulation on the received optical signal. The module operating in the classical communication mode receives the optical signal with a higher ratio and performs IQ modulation on the received optical signal.

4. The light emitting device according to claim 3, characterized in that, In the quantum communication mode: When the pilot light is present, one of the first modulation module and the second modulation module used for quantum state preparation modulates the received optical signal with quantum state based on the loaded random Gaussian modulated electrical signal; In the absence of the pilot light, one of the first modulation module and the second modulation module used for quantum state preparation modulates the received optical signal with quantum state based on the loaded random Gaussian modulated electrical signal and the pilot signal.

5. The light emitting device according to claim 3, characterized in that, The first modulation module or the second modulation module includes: The first beam splitter is used to split the received optical signal into a first optical component and a second optical component. A first intensity modulation module is used to modulate the intensity of the first optical component to obtain a third optical component; The second intensity modulation module is used to modulate the intensity of the second optical component to obtain the fourth optical component; The first phase shifter is used to shift the phase of the third optical component to obtain the fifth optical component; The second phase shifter is used to shift the phase of the fourth optical component to obtain the sixth optical component; The first beam combiner combines the fifth and sixth optical components to obtain the output optical signal.

6. The light emitting device according to claim 5, characterized in that, The beam splitting module, the first intensity modulation module, and the second intensity modulation module are all dynamic intensity modulation modules, and the dynamic intensity modulation module includes: First multimode interference coupler, third phase shifter, fourth phase shifter, fifth phase shifter, sixth phase shifter, second multimode interference coupler; The first multimode interference coupler is a single-input dual-output type, and the second multimode interference coupler is a dual-input single-output type; the third and fourth phase shifters are high-speed phase shifters, and the fifth and sixth phase shifters are low-speed phase shifters; the high-speed phase shifters operate in different communication modes based on different applied electrical signals; The third phase shifter and the fifth phase shifter are connected between the first output terminal of the first multimode interference coupler and the first input terminal of the second multimode interference coupler; The fourth phase shifter and the sixth phase shifter are connected between the second output terminal of the first multimode interference coupler and the second input terminal of the second multimode interference coupler.

7. The light emitting device according to claim 6, characterized in that, The third and fourth phase shifters are both carrier depletion modulators, while the first, second, fifth, and sixth phase shifters are all thermo-optical phase shifters.

8. The light emitting device according to claim 1, characterized in that, The optical emitting device further includes: a first adjustable attenuation module and a second adjustable attenuation module; wherein: The first adjustable attenuation module is connected between the output of the first modulation module and the first input of the beam combining module; The second adjustable attenuation module is connected between the output of the second modulation module and the second input of the beam combining module; The attenuation of the received optical signal by the first adjustable attenuation module and the second adjustable attenuation module meets the attenuation requirements of the communication mode.

9. The light emitting device according to claim 8, characterized in that, The first adjustable attenuation module and the second adjustable attenuation module are dynamic intensity modulation modules or variable optical attenuators.

10. The light emitting device according to any one of claims 1-9, characterized in that, The beam combining module is a polarization rotating beam splitter or a two-dimensional grating coupler.

11. An optical chip, characterized in that, include: The optical emitting device according to any one of claims 1-10 is used to receive the initial optical signal and output the target optical signal; An optical receiving device is used to receive target optical signals transmitted from the outside, decode the target optical signals, and obtain detection information.

12. The optical chip according to claim 11, characterized in that, The optical receiving device includes: A polarization beam splitter module is used to receive a target optical signal transmitted from an external source, split the target optical signal into beams, and obtain a first beam splitter signal and a second beam splitter signal; the optical path of the polarization beam splitter module is the same as and the reverse of the optical path of the beam combining module that synthesizes the target optical signal. The second beam splitter is used to receive the local oscillator light signal and split the local oscillator light signal to obtain the first local oscillator light and the second local oscillator light. The third beam splitter is used to receive the first beam splitting signal and the first local oscillator light, and output two light components after interference. The fourth beam splitter is used to receive the second beam splitting signal and the second local oscillator light, and output two light components after interference; The detection module is used to detect the optical components output by the third beam splitter and the fourth beam splitter, and output detection information.

13. The optical chip according to claim 12, characterized in that, The optical receiving device further includes: The compensation module is used to compensate for the difference in the optical components output by the third beam splitter and the fourth beam splitter.

14. An optical communication system, characterized in that, The optical communication system further includes the optical chip as described in any one of claims 11-13, and further includes: A first laser is used to emit the initial optical signal; A control module is used to control the optical chip to operate in different communication modes.

15. The optical communication system according to claim 14, characterized in that, The optical communication system also includes: The first polarization controller is used to adjust the polarization of the initial optical signal and then transmit it to the optical chip's optical emitting device. The second polarization controller is used to adjust the polarization of the target optical signal received by the optical chip and then transmit it to the optical receiving device of the optical chip.

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