An optical module

Abstract

The application discloses an optical module, comprising: a first laser emitting a first emission light of a Gaussian mode without a signal; a first coupler receiving the first emission light and dividing the first emission light into sub-emission light and first pilot light; a first modulator arranged at a first output port of the first coupler and used for phase modulation of the sub-emission light to generate sub-signal light; an optical fiber extension line arranged between a second output port of the first coupler and a vortex mode multiplexing module; and the vortex mode multiplexing module having a first input end connected with an output end of the first modulator and a second input end connected with the optical fiber extension line and used for converting the first pilot light and the sub-signal light into different vortex modes respectively and combining the vortex modes into a vortex signal emission light. The optical module provided by the application has the same frequency of signal light and pilot light in the emission light, and the signal light and the pilot light are transmitted in a vortex ring fiber in a vortex mode multiplexing mode, so that the communication quality and the communication capacity are improved.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to an optical module. Background Technology

[0002] The rapid development of emerging high-speed data communication services has led to an exponential increase in global data traffic, placing immense pressure on network traffic in typical short-to-medium-distance optical communications systems such as data centers and metropolitan area networks. Currently, intensity modulation / direct detection (IM / DCD) schemes are commonly used in short-to-medium-distance optical communications. While this approach is cost-effective and can effectively control communication system costs, it cannot utilize the phase information of the optical carrier, wasting spectrum resources. Its communication capacity and spectral efficiency are too small to cope with the current explosive growth in communication data.

[0003] Coherent optical communication modulates the signal with the amplitude and phase of the optical carrier. At the receiver, a local oscillator optical carrier is mixed with the signal carrier, and balanced detection is used to demodulate the signal. Coherent optical communication fully utilizes the amplitude and phase dimensions of light waves, offering advantages over intensity modulation / direct detection, such as large transmission capacity, high receiver sensitivity, and compatibility with various advanced modulation formats. Furthermore, coherent optical communication can be combined with wavelength division multiplexing (WDM), polarization multiplexing (PDM), time division multiplexing (TDM), and space division multiplexing (SDM) technologies to fully utilize all dimensions of light waves, further improving the system's transmission capacity and spectral efficiency. Mode division multiplexing (MDM) technology, which utilizes multiple mutually orthogonal spatial modes to transmit information in parallel, is an important part of SDM technology. Optical vortex modes with different topological charge numbers are mutually orthogonal, and theoretically, there is an infinite number of topological charge numbers for each vortex mode. This diversity of values ​​makes optical vortex mode multiplexing a promising solution for improving communication capacity. The combination of coherent optical communication and vortex mode multiplexing technology can significantly improve system communication capacity in short-to-medium distance optical interconnects.

[0004] Traditional coherent optical communication requires high-performance lasers with stable wavelengths and narrow linewidths. These lasers are very expensive, and during coherent detection, the frequency offset between the signal light and the local oscillator, as well as the phase noise of the laser, significantly degrades the signal. Digital signal processing at the receiver requires complex frequency offset compensation and carrier phase recovery algorithms. Coherent optical communication is structurally complex and requires expensive components, resulting in high system complexity, power consumption, and cost. However, short-distance optical interconnects in data centers require communication systems with low complexity, low power consumption, and low cost. Summary of the Invention

[0005] This application provides an optical module to improve the communication rate of the optical module.

[0006] To address the aforementioned technical problems, the embodiments of this application disclose the following technical solutions:

[0007] This application discloses an optical module, including:

[0008] The first laser emits a first emitted light without a signal, and the first emitted light is Gaussian mode light.

[0009] A first coupler receives the first emitted light and splits the first emitted light into a sub-emitted light and a first pilot light.

[0010] A first modulator, disposed at the first output port of the first coupler, is used to perform phase modulation on the sub-emitted light to generate sub-signal light;

[0011] An optical fiber extension line is disposed between the second output port of the first coupler and the vortex mode multiplexing module;

[0012] The vortex mode multiplexing module has a first input port connected to the output of the first modulator and a second input port connected to the optical fiber extension line. It is used to convert the first pilot light and the sub-signal light into different vortex modes and combine them into a beam of vortex signal emission light.

[0013] Beneficial effects:

[0014] This application discloses an optical module for realizing self-zero-difference coherent optical communication, comprising: a first laser emitting a first emitted light without a signal, the first emitted light being Gaussian mode light; a first coupler receiving the first emitted light and splitting it into a sub-emitted light and a first pilot light; a first modulator disposed at a first output port of the first coupler for phase modulation of the sub-emitted light to generate a sub-signal light; an optical fiber extension line disposed between a second output port of the first coupler and a vortex mode multiplexing module; the vortex mode multiplexing module having a first input port connected to the output of the first modulator and a second input port connected to the optical fiber extension line, for converting the first pilot light and the sub-signal light into different vortex modes respectively, and combining them into a single vortex signal emitted light beam. In the optical module provided in this application, the signal light and pilot light emitted by the optical emitting component are generated by the same laser and have the same frequency. Furthermore, the signal light and pilot light are transmitted in a vortex-ring fiber using different vortex modes, which helps to improve communication quality and increase communication capacity, and overcomes the limitations of high power consumption, high complexity and high cost of traditional coherent detection. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual flow of the method, the actual timing of the signals, etc. involved in the embodiments of this disclosure.

[0016] Figure 1 This is a connection diagram of an optical communication system according to some embodiments;

[0017] Figure 2 This is a structural diagram of an optical network terminal according to some embodiments;

[0018] Figure 3 This is a structural diagram of an optical module according to some embodiments;

[0019] Figure 4 An exploded view of an optical module according to some embodiments;

[0020] Figure 5 This is a schematic diagram of a light emitting component structure shown in an embodiment of this application;

[0021] Figure 6 This is a schematic diagram of the optical path of an optical emitting component according to an embodiment of this application;

[0022] Figure 7 This is a schematic diagram of a vortex mode multiplexing module structure shown in an embodiment of this application;

[0023] Figure 8 A schematic diagram of a vortex ring fiber cross-section provided in an embodiment of this application;

[0024] Figure 9 This application embodiment shows a schematic diagram of another vortex mode multiplexing module;

[0025] Figure 10 This is a schematic diagram of an optical receiving component structure shown in an embodiment of this application;

[0026] Figure 11 This is a schematic diagram of a light receiving component according to an embodiment of this application;

[0027] Figure 12 This is a schematic diagram of a vortex mode demultiplexing module structure shown in an embodiment of this application;

[0028] Figure 13 This is a schematic diagram of another vortex mode demultiplexing module shown in an embodiment of this application;

[0029] Figure 14 This application provides a schematic diagram of a self-zero difference coherent detection system structure.

[0030] Figure 15 This application provides a schematic diagram of a pilot optical path and signal optical path length alignment module for self-zero difference coherent detection based on vortex mode multiplexing. Detailed Implementation

[0031] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0032] Unless the context otherwise requires, throughout the specification and claims, the term "comprise" and its other forms, such as the third-person singular "comprises" and the present participle "comprising," are interpreted as open-ended and encompassing, meaning "including, but not limited to." In the description of the specification, terms such as "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific example," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0033] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0034] In describing some embodiments, the terms "coupled" and "connected," and their derivative expressions, may be used. For example, the term "connected" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact with each other. Similarly, the term "coupled" may be used in describing some embodiments to indicate that two or more components have direct physical or electrical contact. However, the terms "coupled" or "communicatively coupled" may also refer to two or more components that do not have direct contact with each other but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the content of this document.

[0035] "At least one of A, B and C" has the same meaning as "at least one of A, B or C", both including the following combinations of A, B and C: only A, only B, only C, combinations of A and B, combinations of A and C, combinations of B and C, and combinations of A, B and C.

[0036] "A and / or B" includes the following three combinations: A only, B only, and a combination of A and B.

[0037] The use of “applies to” or “configured to” in this article implies an open and inclusive language that does not preclude applicability to or configuration to devices that perform additional tasks or steps.

[0038] As used herein, “about,” “approximately,” or “approximately” includes the stated value and the average value within an acceptable range of deviation from the given value, wherein the acceptable range of deviation is determined by a person skilled in the art taking into account the measurement under discussion and the error associated with the measurement of the given quantity (i.e., the limitations of the measurement system).

[0039] In optical communication technology, light carries the information to be transmitted, and the information-carrying optical signal is transmitted to information processing equipment such as computers through information transmission equipment such as optical fibers or optical waveguides to complete the information transmission. Because optical signals have passive transmission characteristics when transmitted through optical fibers or optical waveguides, low-cost and low-loss information transmission can be achieved. However, the signals transmitted by information transmission equipment such as optical fibers or optical waveguides are optical signals, while the signals that information processing equipment such as computers can recognize and process are electrical signals. Therefore, in order to establish an information connection between information transmission equipment such as optical fibers or optical waveguides and information processing equipment such as computers, it is necessary to realize the mutual conversion between electrical signals and optical signals.

[0040] In the field of optical fiber communication technology, optical modules realize the aforementioned functions of converting between optical signals and electrical signals. An optical module includes an optical port and an electrical port. The optical port enables optical communication with information transmission devices such as optical fibers or optical waveguides, while the electrical port enables electrical connection with optical network terminals (e.g., optical modems). The electrical connection is mainly used for power supply, I2C signal transmission, data signal transmission, and grounding. The optical network terminal transmits electrical signals to information processing devices such as computers via network cables or Wi-Fi.

[0041] Figure 1 This is a connection diagram of an optical communication system according to some embodiments. Figure 1 As shown, the optical communication system mainly includes a remote server 1000, a local information processing device 2000, an optical network terminal 100, an optical module 200, an optical fiber 101, and a network cable 103.

[0042] One end of optical fiber 101 is connected to the remote server 1000, and the other end is connected to the optical network terminal 100 via optical module 200. Optical fiber itself can support long-distance signal transmission, such as signal transmission over several kilometers (6 to 8 kilometers). Theoretically, ultra-long-distance transmission can be achieved by using repeaters. Therefore, in typical optical communication systems, the distance between the remote server 1000 and the optical network terminal 100 can usually reach several kilometers, tens of kilometers, or hundreds of kilometers.

[0043] One end of the network cable 103 is connected to the local information processing device 2000, and the other end is connected to the optical network terminal 100. The local information processing device 2000 can be any one or more of the following devices: router, switch, computer, mobile phone, tablet computer, television, etc.

[0044] The physical distance between the remote server 1000 and the optical network terminal 100 is greater than the physical distance between the local information processing device 2000 and the optical network terminal 100. The connection between the local information processing device 2000 and the remote server 1000 is completed by optical fiber 101 and network cable 103; while the connection between optical fiber 101 and network cable 103 is completed by optical module 200 and optical network terminal 100.

[0045] The optical module 200 includes an optical port and an electrical port. The optical port is configured to connect to the optical fiber 101, thereby establishing a bidirectional optical signal connection between the optical module 200 and the optical fiber 101. The electrical port is configured to connect to the optical network terminal 100, thereby establishing a bidirectional electrical signal connection between the optical module 200 and the optical network terminal 100. The optical module 200 performs mutual conversion between optical and electrical signals, thereby establishing a connection between the optical fiber 101 and the optical network terminal 100. For example, optical signals from the optical fiber 101 are converted into electrical signals by the optical module 200 and then input to the optical network terminal 100, while electrical signals from the optical network terminal 100 are converted into optical signals by the optical module 200 and then input to the optical fiber 101.

[0046] The optical network terminal 100 includes a generally rectangular housing, and an optical module interface 102 and a network cable interface 104 disposed on the housing. The optical module interface 102 is configured to connect to an optical module 200, thereby establishing a bidirectional electrical signal connection between the optical network terminal 100 and the optical module 200; the network cable interface 104 is configured to connect to a network cable 103, thereby establishing a bidirectional electrical signal connection between the optical network terminal 100 and the network cable 103. The optical module 200 and the network cable 103 are connected through the optical network terminal 100. For example, the optical network terminal 100 transmits electrical signals from the optical module 200 to the network cable 103, and transmits signals from the network cable 103 to the optical module 200. Therefore, the optical network terminal 100 acts as a host computer for the optical module 200, monitoring the operation of the optical module 200. Besides the optical network terminal 100, the host computer for the optical module 200 may also include an optical line terminal (OLT), etc.

[0047] The remote server 1000 establishes a bidirectional signal transmission channel with the local information processing equipment 2000 through optical fiber 101, optical module 200, optical network terminal 100 and network cable 103.

[0048] Figure 2 This is a structural diagram of an optical network terminal according to some embodiments, to clearly show the connection relationship between the optical module 200 and the optical network terminal 100. Figure 2 Only the structure of the optical network terminal 100 related to the optical module 200 is shown. For example... Figure 2 As shown, the optical network terminal 100 also includes a PCB circuit board 105 disposed within a housing, a cage 106 disposed on the surface of the PCB circuit board 105, and an electrical connector disposed inside the cage 106. The electrical connector is configured to connect to the electrical port of the optical module 200; the heat sink 107 has protrusions such as fins to increase the heat dissipation area.

[0049] The optical module 200 is inserted into the cage 106 of the optical network terminal 100, where it is secured. Heat generated by the optical module 200 is conducted to the cage 106 and then dissipated through the heat sink 107. After insertion into the cage 106, the optical module 200's electrical port connects to an electrical connector inside the cage 106, establishing a bidirectional electrical signal connection between the optical module 200 and the optical network terminal 100. Furthermore, the optical port of the optical module 200 connects to the optical fiber 101, establishing a bidirectional electrical signal connection between the optical module 200 and the optical fiber 101.

[0050] Figure 3 This is a structural diagram of an optical module according to some embodiments. Figure 4 This is an exploded view of an optical module according to some embodiments. Figure 3 and Figure 4 As shown, the optical module 200 includes a housing, a circuit board 300 disposed in the housing, and an optical transceiver assembly.

[0051] The housing includes an upper housing 201 and a lower housing 202, with the upper housing 201 covering the lower housing 202 to form the aforementioned housing having two openings 204 and 205; the outer contour of the housing is generally square.

[0052] In some embodiments of this disclosure, the lower housing 202 includes a bottom plate and two lower side plates located on both sides of the bottom plate and arranged perpendicularly to the bottom plate; the upper housing 201 includes a cover plate and two upper side plates located on both sides of the cover plate and arranged perpendicularly to the cover plate, and the two side plates are combined with the two side walls to realize that the upper housing 201 covers the lower housing 202.

[0053] The direction of the line connecting the two openings 204 and 205 can be consistent with or inconsistent with the length direction of the optical module 200. For example, opening 204 is located at the end of the optical module 200. Figure 3 The opening 205 is also located at the end of the optical module 200 (left end). Figure 3 (The right end). Alternatively, opening 204 is located at the end of optical module 200, while opening 205 is located on the side of optical module 200. Opening 204 is an electrical port, through which the gold fingers of circuit board 300 extend and are inserted into a host computer (such as optical network terminal 100); opening 205 is an optical port, configured to connect to an external optical fiber 101, so that the optical fiber 101 can connect to the optical transceiver components inside optical module 200.

[0054] The assembly method using an upper housing 201 and a lower housing 202 facilitates the installation of components such as the circuit board 300 and optical transceiver modules into the housing, which provides encapsulation and protection for these components. Furthermore, the assembly of components such as the circuit board 300 facilitates the deployment of positioning, heat dissipation, and electromagnetic shielding components, promoting automated production.

[0055] In some embodiments, the upper housing 201 and the lower housing 202 are generally made of metal materials, which facilitates electromagnetic shielding and heat dissipation.

[0056] In some embodiments, the optical module 200 further includes an unlocking component 203 located on the outer wall of its housing. The unlocking component 203 is configured to establish a fixed connection between the optical module 200 and the host computer, or to release the fixed connection between the optical module 200 and the host computer.

[0057] For example, the unlocking component 203 is located on the outer wall of the two lower side plates 2022 of the lower housing 202, and includes a locking component that matches the cage of the host computer (e.g., the cage 106 of the optical network terminal 100). When the optical module 200 is inserted into the cage of the host computer, the locking component of the unlocking component 203 fixes the optical module 200 in the cage of the host computer; when the unlocking component 203 is pulled, the locking component of the unlocking component 203 moves accordingly, thereby changing the connection relationship between the locking component and the host computer, so as to release the locking relationship between the optical module 200 and the host computer, thereby allowing the optical module 200 to be pulled out of the cage of the host computer.

[0058] Circuit board 300 includes circuit traces, electronic components, and chips. The circuit traces connect the electronic components and chips according to the circuit design to achieve functions such as power supply, electrical signal transmission, and grounding. Electronic components may include, for example, capacitors, resistors, transistors, and metal-oxide-semiconductor field-effect transistors (MOSFETs). Chips may include, for example, microcontroller units (MCUs), limiting amplifiers, clock and data recovery chips (CDRs), power management chips, and digital signal processing (DSP) chips.

[0059] Circuit board 300 is generally a rigid circuit board. Due to its relatively hard material, the rigid circuit board can also perform a load-bearing function. For example, the rigid circuit board can stably support the chip; the rigid circuit board can also be inserted into the electrical connector in the host computer cage.

[0060] The circuit board 300 also includes gold fingers 301 formed on its end surface, the gold fingers 301 consisting of a plurality of independent pins. The circuit board 300 is inserted into the cage 106 and is electrically connected to an electrical connector within the cage 106 by the gold fingers 301. The gold fingers 301 may be provided only on one side of the surface of the circuit board 300 (e.g., Figure 4 The upper surface shown can also be placed on the upper and lower surfaces of the circuit board 300 to accommodate applications with a large number of pins. The gold fingers 301 are configured to establish an electrical connection with the host computer to achieve power supply, grounding, I2C signal transmission, and data signal transmission. Of course, flexible circuit boards are also used in some optical modules. Flexible circuit boards are generally used in conjunction with rigid circuit boards as a supplement to rigid circuit boards.

[0061] Optical transceiver components include optical transmitting components and optical receiving components.

[0062] Figure 5 This is a schematic diagram of a light emitting component structure shown in an embodiment of this application, such as... Figure 5 As shown, to improve optical communication capacity, the optical emitting component provided in this application includes: a first laser 401 and a first coupler 402 disposed at the optical emitting end of the first laser 401. The first coupler 402 is provided with multiple output ports, including a first output port, a second output port, and a third output port. A first modulator 403 is connected to the first output port of the first coupler 402, a second modulator 404 is connected to the second output port of the first coupler 402, and a vortex mode multiplexing module 406 is connected to the third output ports of the first modulator 403, the second modulator 404, and the first coupler 402 respectively, converting the signal light into a vortex mode and multiplexing it into a beam. In this application, the first modulator and the second modulator load data onto the signal light, and the light output from the third output port serves as pilot light. The transmitted light is converted into vortex light with different angular momentum by the vortex mode multiplexing module 406. The signal light and the pilot light are transmitted using different vortex mode channels. The receiving end receives the pilot light and uses it as local oscillator light to achieve coherent detection with zero difference. This eliminates the influence of frequency offset and phase noise, eliminates the need for complex carrier recovery algorithms, and reduces the complexity, power consumption and cost of the coherent detection system. It breaks through the limitations of high power consumption, high complexity and high cost of traditional coherent detection.

[0063] Figure 6 This is a schematic diagram of the optical path of an optical emitting component shown in an embodiment of this application, such as... Figure 6As shown, a first laser 401 is used to emit a first emitted light as a light source. A first coupler 402 is used to split the first emitted light into multiple paths. In this application, the first coupler 402 is provided with three output ports: a first output port, a second output port, and a third output port, splitting the first emitted light into three paths as signal light or pilot light. The first output port outputs the first sub-emitted light, the second output port outputs the second sub-emitted light, and the third output port outputs the third sub-emitted light. The first and second sub-emitted lights serve as signal light, and the third sub-emitted light serves as the first pilot light.

[0064] The first modulator 403 receives and modulates the first sub-emitted light to generate a first sub-signal light, wherein the first sub-signal light carries a first data signal. The second modulator 404 receives and modulates the second sub-emitted light to generate a second sub-signal light, wherein the second sub-signal light carries a second data signal. In the figure, solid lines represent Gaussian mode light, dashed lines represent vortex mode light, and arrows indicate the direction of light propagation.

[0065] Furthermore, an optical fiber extension line 405 is provided between the third output port of the first coupler 402 and the vortex mode multiplexing module 406, so that the pilot light path and the signal light path are equal, eliminating the influence of frequency offset and phase noise, and making the transmitted signal light and pilot light have the same phase change, reducing system complexity, power consumption and cost.

[0066] The vortex mode multiplexing module 406 receives a first sub-signal light, a second sub-signal light, and a pilot light. It converts these three sub-signal lights into different vortex modes and multiplexes them to generate a first vortex transmitted light signal. Specifically, the vortex mode multiplexing module 406 has a first input port connected to the output of the first modulator 403 to receive the first sub-signal light; a second input port connected to the output of the second modulator 404 to receive the second sub-signal light; and a third input port connected to the third output port of the first coupler 402 to receive the first pilot light.

[0067] The output of the vortex mode multiplexing module 406 is connected to the first transmitting optical fiber 407, and the first vortex transmitting signal light is sent out through the first optical fiber.

[0068] In this embodiment, the first transmitting fiber 407 is a vortex ring fiber.

[0069] Figure 7 This is a schematic diagram of a vortex mode multiplexing module structure shown in an embodiment of this application, as follows: Figure 7As shown, the vortex mode multiplexing module 406 is a free-space optical device vortex mode multiplexing module 406, including a collimator, a polarizer, a spatial light modulator, a beam combiner, and a converging lens. The collimator collimates the Gaussian signal light in the single-mode fiber and outputs it into free space. The polarizer is used to adjust the polarization direction of the Gaussian signal light to the polarization direction of the spatial light modulator. The spatial light modulator is used to convert the Gaussian light into a vortex mode. The beam combiner is used to multiplex the two generated vortex modes. The converging lens is used to couple the free-space multiplexed vortex modes into the first transmitting fiber.

[0070] Specifically, a first collimator 4061 is disposed in the outgoing optical path of the first sub-signal light to collimate the first sub-signal light. A first polarizer 4062 is disposed between the first spatial light modulator 4063 and the first collimator 4061 to adjust the polarization direction of the first sub-signal light to the working direction of the first spatial light modulator 4063. The first sub-signal light is modulated by the first spatial light modulator 4063 to generate a first sub-vortex light.

[0071] The second collimator 4065 is disposed in the output optical path of the second sub-signal light and is used to collimate the second sub-signal light. The second polarizer 4066 is disposed between the second spatial light modulator 4067 and the second collimator 4065 and is used to adjust the polarization direction of the second sub-signal light to the working direction of the second spatial light modulator 4067. The second sub-signal light is modulated by the second spatial light modulator 4067 to generate a second sub-vortex light.

[0072] The third collimator 4069 is placed in the output optical path of the first pilot light to collimate the first pilot light. The third polarizer 40610 is disposed between the third spatial light modulator 40611 and the third collimator to adjust the polarization direction of the first pilot light to the working direction of the third spatial light modulator 40611. The first pilot light is modulated by the third spatial light modulator 40611 to generate the first pilot vortex light.

[0073] The first beam combiner 4068 is disposed on the output optical path of the first spatial light modulator 4063 and the second spatial light modulator 4067, and combines the first sub-vortex light and the second sub-vortex light into the first vortex signal light.

[0074] The first beam combiner 4068 reflects the first sub-vortex light and transmits the second sub-vortex light, so that the first and second sub-vortex lights are combined into a single beam after passing through the first beam combiner 4068.

[0075] The second beam combiner 40612 is disposed on the output optical path of the third spatial light modulator 40611 and the first beam combiner 4068, and combines the first vortex signal light and the first pilot vortex light into the first vortex emission light.

[0076] The first sub-signal light, the second sub-signal light, and the first pilot light are converted into vortex modes and multiplexed by the vortex mode multiplexing module 406 to generate the first vortex emission light.

[0077] In some embodiments of this application, the first coupler 402 may divide the first emitted light into several paths, which can be set according to actual needs. It may be 3 paths as shown in this application, or 4 paths, 5 paths or others.

[0078] The spatial light modulator provided in this application embodiment is a reflective spatial light modulator, and the angle between its input optical path and output optical path is as small as possible.

[0079] In some embodiments of this application, the vortex mode used to transmit the first pilot light can be a 0th-order vortex mode, a 1st-order vortex mode, or a vortex mode of other orders.

[0080] To reduce crosstalk between the signal light and the first pilot light, the signal light and the first pilot light are multiplexed using vortex modes of different orders in a vortex ring fiber. The crosstalk between the vortex modes used is less than -15dB, which helps to improve communication quality.

[0081] Figure 8 This is a schematic diagram of a cross-section of a vortex-type ring fiber provided in an embodiment of this application. As shown in the figure, in some embodiments of this application, the vortex-type ring fiber includes a central region 601, a ring core 602, and a cladding 603. The cladding is fluorine-doped, and its refractive index is lower than that of silicon dioxide. The relative refractive index difference between the cladding and silicon dioxide does not exceed 0.7%. The central region has the same refractive index as the cladding. The relative refractive index difference between the ring core and the cladding does not exceed 1%. The refractive index of the core is greater than that of the cladding. The inner diameter of the ring core region is 2μm to 10μm, and its width is 1μm to 20μm. The vortex-type ring fiber only supports multi-channel radial first-order vortex modes and is divided into different mode groups. The first mode group has 2 modes, and each of the other mode groups has 4 modes. Except for the first two mode groups, the effective refractive index difference between the remaining mode groups is >10. -4 .

[0082] Because the beam-combined light spot is relatively large, in some embodiments of this application, the optical emitting assembly is further provided with a first converging lens 40613, which is disposed on the output optical path of the second beam combiner 40612, for converging the first vortex emitted light onto the first transmitting optical fiber 407 and transmitting it to the peer optical module. The converging light spot of the first converging lens 40613 is located on the end face of the first transmitting optical fiber 407, improving communication accuracy.

[0083] Figure 9This application provides a schematic diagram of another vortex mode multiplexing module, as shown in the figure. This application also provides another vortex mode multiplexing module including:

[0084] The first single-mode fiber 40620 is connected at one end to the output of the first modulator 403 and at the other end to one end of the first vortex loop fiber 40621, thereby exciting the first vortex mode OAM in the vortex loop fiber. 01 The first sub-signal light is converted into a first sub-vortex light. A second single-mode fiber 40622 is connected at one end to the output of the second modulator 404 to transmit the second sub-signal light. A first tapered coupler 40623 has its first input end connected to the other end of the first vortex ring fiber 40621, its second input end connected to the other end of the second single-mode fiber 40622, and its output end connected to one end of the second vortex ring fiber 40624. The first tapered coupler 40623 receives the second sub-signal light and the first sub-vortex light; the second sub-signal light is converted into a second sub-vortex light; and the vortex mode of the second sub-vortex light is OAM. 11 OAM 01 Patterns and OAM 11 The mode is multiplexed and transmitted within the second vortex ring fiber.

[0085] The third vortex ring fiber 40625 is connected at one end to the other end of the second vortex ring fiber 40624.

[0086] The third single-mode fiber 40626 is connected at one end to the output end of the fiber extension cable 405.

[0087] The second tapered coupler 40627 has its first input end connected to the other end of the third vortex ring fiber 40625, its second input end connected to the other end of the third single-mode fiber 40626, and its output end connected to the fourth vortex ring fiber 40628. The third vortex ring fiber 40625 and the second vortex ring fiber are soldered to solder joint 500, realizing the cascading of two fiber mode couplers.

[0088] In this process, after pre-tapering and matching the single-mode fiber, the coupling region between the single-mode fiber and the vortex ring fiber is tapered and fused to achieve selective coupling of the vortex modes. Two fiber mode couplers are cascaded to achieve multiplexing of three vortex modes. One single-mode fiber is soldered to the ring fiber at the input end at a solder joint of 40°. The Gaussian mode is transmitted through the single-mode fiber to the vortex ring fiber, exciting the vortex mode OAM in the vortex ring fiber. 01 The Gaussian mode input at the other end of the single-mode fiber is transmitted to tapered coupling region 1, where coupling generates the vortex mode OAM in the ring fiber. 11 OAM 01 Patterns and OAM 11The mode is multiplexed and transmitted in a vortex-loop fiber; the loop fiber at the output of the first fiber mode coupler is welded to the loop fiber at the input of the second fiber mode coupler at a weld point of 500, realizing the cascading of the two fiber mode couplers. The Gaussian mode input of the single-mode fiber of the second fiber mode coupler is transmitted to the tapered coupling region 2, and the vortex mode OAM in the loop fiber is coupled and excited. 21 OAM 21 OAM in Mode and Vortex Loop Fiber 01 OAM 11 The modes are multiplexed together for transmission, enabling the multiplexing of three vortex modes.

[0089] After receiving the first vortex emitted light, the peer optical module demultiplexes the first vortex emitted light, converting the vortex mode light into a Gaussian mode. The first pilot vortex light, after being converted into the first pilot light, is used as the local oscillator light for coherent detection. It performs coherent detection with the demultiplexed signal light, using different vortex mode channels to transmit the signal light and pilot light. The receiving pilot light is used as the local oscillator light to achieve coherent transmission with zero difference, eliminating the influence of frequency offset and phase noise. It eliminates the need for complex carrier recovery algorithms, reducing the complexity, power consumption and cost of coherent communication systems, and breaking through the limitations of high power consumption, high complexity and high cost of traditional coherent detection.

[0090] The optical emitting component provided in this application includes: a first laser, and a first coupler disposed at the optical emitting end of the first laser. The first coupler splits the light emitted by the first laser into three beams. A first modulator modulates the light output from the first coupler, a second modulator modulates the light output from the second output end of the first coupler, and a vortex mode multiplexing module is connected to the third output ports of the first modulator, the second modulator, and the first coupler, respectively, to convert the signal light into a vortex mode and multiplex it into a single beam. In this application, the first and second modulators load data onto the signal light, and the light output from the third output port of the first coupler serves as pilot light. The vortex mode multiplexing module converts the emitted light into vortex light with different angular momentum, enabling the transmission of signal light and pilot light using different vortex mode channels. The receiving end receives the pilot light and uses it as local oscillator light to achieve coherent transmission with zero difference, eliminating the influence of frequency offset and phase noise, eliminating the need for complex carrier recovery algorithms, reducing the complexity, power consumption, and cost of the coherent detection system, and overcoming the limitations of high power consumption, high complexity, and high cost of traditional coherent detection.

[0091] Similarly, after receiving the vortex receiving light from the peer optical module, the vortex receiving light is demultiplexed, and the vortex mode light is converted into a Gaussian mode. The second pilot vortex light is converted into the local oscillator light used for coherent detection after being converted into the receiving pilot light, and coherent detection is performed with the demultiplexed signal light.

[0092] Figure 10This is a schematic diagram of an optical receiving component structure shown in an embodiment of this application. Figure 11 This is a schematic diagram of a light receiving component signal according to an embodiment of this application, such as... Figure 10 and Figure 11 As shown, to achieve demultiplexing of the vortex optical signal transmitted by the peer optical module, the optical receiving component provided in this embodiment includes: a vortex mode demultiplexing module 501, whose input end is connected to the receiving optical fiber 507 to receive vortex received light. The vortex mode demultiplexing module 501 receives the vortex light transmitted by the peer optical module (referred to as vortex received light for convenience), and demultiplexes the vortex received light into a first sub-received signal light, a second sub-received signal light, and a receiving pilot light in Gaussian mode. The vortex mode demultiplexing module 501 has multiple output ports. The first output port outputs the first sub-received signal light and is connected to a first coherent receiver; the second output port outputs the receiving pilot light and is connected to a second coupler; and the third output port outputs the second sub-received signal light and is connected to a second coherent receiver.

[0093] In this embodiment of the application, the vortex receiving light transmitted within the receiving optical fiber is a mixed light of signal light and pilot light with different vortex modes.

[0094] The second coupler 502 has its input end connected to the second output port of the vortex mode demultiplexing module 501, and is used to couple the received pilot light into a first sub-pilot light and a second sub-pilot light.

[0095] A first coherent receiver is connected to the first output port of the vortex mode demultiplexing module 501 and the output of the second coupler 502. It receives a first sub-received signal light and a first sub-pilot light, and performs mixing and balanced detection on the sub-received signal light and the first sub-pilot light. The first coherent receiver includes a third mixer 503, which receives the first sub-received signal light and the first sub-pilot light, and couples them to form a first received mixed light. The output of the third mixer 503 is connected to a first detector 504. The first detector 504 receives the first mixed signal light, converts it into a first electrical signal, and transmits the first electrical signal to a digital processor 310. The digital processor 310 samples the first electrical signal, performs digital signal processing to recover and demodulate the signal, realizing self-zero-difference coherent detection based on vortex mode multiplexing. The first detector is a balanced detector.

[0096] The second coherent receiver receives the second sub-received signal light and the second sub-pilot light, and mixes and balances the second sub-received signal light and the second sub-pilot light. The second coherent receiver includes a fourth mixer 505, which receives the second sub-received signal light and the second sub-pilot light, and mixes them to form a second received mixed light. The output of the fourth mixer 505 is connected to a second detector 506. The second detector 506 receives the first received mixed light, performs balance detection on the first received mixed light to convert it into a second electrical signal, and transmits the second electrical signal to a digital processor 310. The digital processor 310 samples the second electrical signal, recovers and demodulates the signal through digital signal processing, realizing self-zero difference coherent detection based on vortex mode multiplexing. The second detector 506 is a balanced detector.

[0097] In some embodiments of this application, the receiving optical fiber 507 is also connected to an external optical fiber to transmit the first received signal light emitted by the peer optical module, which is the vortex received light emitted by the peer optical module.

[0098] Based on the reversibility of light, the vortex mode demultiplexing module and the vortex mode multiplexing module have the same structure, which can realize the demultiplexing of multiple sets of vortex signal light.

[0099] Figure 11 Solid arrows indicate Gaussian light transmission paths, while dashed arrows represent vortex mode light transmission paths.

[0100] Figure 12 This is a schematic diagram of a vortex mode demultiplexing module structure shown in an embodiment of this application, as follows: Figure 12 As shown, the vortex mode demultiplexing module 501 is a free-space optical device vortex mode multiplexing module, including a converging lens, a polarizer, a spatial light modulator, a beam splitter, and a converging lens. The beam splitter is used to split light of different vortex modes. The split vortex light is adjusted to a Gaussian mode by the spatial light modulator, then adjusted to unpolarized light by the polarizer, and finally converged to the exit end by the converging lens.

[0101] Specifically, the first collimating lens 5011 is disposed at the outlet of the receiving optical fiber 507 to collimate the vortex receiving light.

[0102] The first beam splitter 5012 is disposed on the light output path of the first collimating lens 5011 to split the vortex receiving light into a first vortex receiving pilot light and a second vortex receiving signal light.

[0103] A fourth spatial light modulator 5013 is disposed on the first output optical path of the first beam splitter 5012, used to convert the first vortex received pilot light from vortex mode to Gaussian mode, hereinafter referred to as the received pilot light. A fourth polarizer 5014 is disposed between the fourth spatial light modulator 5013 and the second converging lens 5015, used to adjust the polarization direction of the received pilot light and eliminate the polarization state. The second converging lens 5015 is used to focus the received pilot light and transmit it to the second coupler 502. The second converging lens 5015 is located at the second output port of the vortex mode demultiplexing module 501.

[0104] The second coupler 502 splits the received pilot light into a first sub-pilot light and a second sub-pilot light.

[0105] The second beam splitter 5016 is disposed on the second output optical path of the first beam splitter 5012, and is used to split the second vortex receiving signal light into two beams, namely the third sub-signal light and the fourth sub-signal light. At this time, the first sub-received signal light and the second sub-received signal light are in vortex mode, and are different vortex modes.

[0106] A fifth spatial light modulator 5017 is disposed on the first output optical path of the second beam splitter 5016, used to convert the third sub-signal light from vortex mode to Gaussian mode. A fifth polarizer 5018 is disposed between the fifth spatial light modulator 5017 and the third converging lens 5019, used to adjust the polarization direction of the first sub-received signal light and eliminate polarization state. The third converging lens 5019 is used to focus the received pilot light and transmit it to the third mixer 503. The third converging lens 5019 is located at the first output port of the vortex mode demultiplexing module 501.

[0107] A sixth spatial light modulator 50110 is disposed on the second output optical path of the second beam splitter 5016, used to convert the fourth sub-signal light from vortex mode to Gaussian mode. A sixth polarizer 50111 is disposed between the sixth spatial light modulator 50110 and the fourth converging lens 50112, used to adjust the polarization direction of the first sub-received signal light and eliminate the polarization state. A third converging lens 5019 is used to focus the received pilot light and transmit it to the fourth mixer 505. The third converging lens 5019 is located at the third output port of the vortex mode demultiplexing module 501.

[0108] The input port of the vortex mode demultiplexing module 501 receives vortex receiving light, which is a mixed mode of signal light and pilot light with different vortex modes. The light output by its output terminal is in Gaussian mode, wherein the first output port outputs the first sub-received signal light in Gaussian mode, the second output port outputs the received pilot light in Gaussian mode, and the third output port outputs the second sub-received signal light in Gaussian mode.

[0109] In some embodiments of this application, the second coupler 502 receives the pilot light in several paths, which can be set according to actual needs. It can be three paths as shown in this application, or four, five, or others. In this application, the second coupler 502 specifically receives the pilot light as a first sub-pilot light and a second sub-pilot light.

[0110] The spatial light modulator provided in this application embodiment is a reflective spatial light modulator, and the angle between its input optical path and output optical path is as small as possible.

[0111] In some embodiments of this application, the vortex mode used for transmitting and receiving pilot light can be a 0th-order vortex mode, a 1st-order vortex mode, or a vortex mode of other orders.

[0112] Figure 13 This is a schematic diagram of another vortex mode demultiplexing module shown in an embodiment of this application, as follows: Figure 13 As shown, this application also provides another vortex mode multiplexing module, including:

[0113] The third tapered coupler 50122 has its first input end connected to the first receiving vortex loop fiber 50120, and its second input end connected to the first receiving single-mode fiber 50121. The first receiving vortex loop fiber 50120 contains a mixed beam of pilot light and received signal light with different vortex modes. As shown in the figure, the first receiving vortex loop fiber 50120 includes a first sub-received signal light of vortex mode OAM1, a receiving pilot light of OAM2, and a second sub-received signal light of OAM3. The first output end of the third tapered coupler 50122 is connected to the second receiving single-mode fiber 50123, serving as the first output port of the vortex mode multiplexing module. The second receiving single-mode fiber 50123 outputs a first sub-received signal light in Gaussian mode. The second output end of the third tapered coupler 50122 is connected to the second receiving vortex loop fiber 50124, which contains the receiving pilot light of vortex mode OAM2 and the second sub-received signal light of OAM3.

[0114] The fourth tapered coupler 50125 has its first input end connected to the third receiving vortex loop fiber 50126, and its second input end connected to the third receiving single-mode fiber 50129. The third receiving vortex loop fiber 50126 and the second receiving vortex loop fiber 50124 are connected at solder joint 600, and each contains the receiving pilot light for vortex mode OAM2 and the second sub-receive signal light for OAM3. The third receiving single-mode fiber 50129 has no light input. The first output end of the fourth tapered coupler 50125 is connected to the fourth receiving single-mode fiber 50127, serving as the second output port of the vortex mode multiplexing module. The fourth receiving single-mode fiber 50127 outputs Gaussian mode receiving pilot light. The second output end of the fourth tapered coupler 50125 is connected to the fourth receiving vortex loop fiber 50128, which contains the second sub-receive signal light for vortex mode OAM3.

[0115] The fourth receiving single-mode fiber 50127 is connected to the fifth receiving single-mode fiber 50130. The second sub-receiving signal light is converted from vortex mode to Gaussian mode. The fourth receiving vortex ring fiber 50128 is connected to the third output port of the vortex mode multiplexing module.

[0116] In this application, the vortex receiving light transmitted by the peer optical module is received, the vortex receiving light is demultiplexed, and the vortex mode light is converted into a Gaussian mode. The second pilot vortex light is converted into the receiving pilot light and used as the local oscillator light for coherent detection. Coherent detection is performed with the demultiplexed signal light. The signal light and pilot light are transmitted using different vortex mode channels. The receiving pilot light is used as the local oscillator light to achieve coherent transmission with zero difference, eliminating the influence of frequency offset and phase noise. It eliminates the need for complex carrier recovery algorithms, reduces the complexity, power consumption and cost of coherent communication systems, and breaks through the limitations of high power consumption, high complexity and high cost of traditional coherent detection.

[0117] The optical emitting component provided in this application includes: a first laser, and a first coupler disposed at the optical emitting end of the first laser. The first coupler splits the light emitted by the first laser into three beams. A first modulator modulates the light output from the first coupler, a second modulator modulates the light output from the second output end of the first coupler, and a vortex mode multiplexing module is connected to the third output ports of the first modulator, the second modulator, and the first coupler, respectively, to convert the signal light into a vortex mode and multiplex it into a single beam. In this application, the first and second modulators load data onto the signal light, and the light output from the third output port of the first coupler serves as pilot light. The vortex mode multiplexing module converts the emitted light into vortex light with different angular momentum, enabling the transmission of signal light and pilot light using different vortex mode channels. The receiving end receives the pilot light and uses it as local oscillator light to achieve coherent transmission with zero difference, eliminating the influence of frequency offset and phase noise, eliminating the need for complex carrier recovery algorithms, reducing the complexity, power consumption, and cost of the coherent detection system, and overcoming the limitations of high power consumption, high complexity, and high cost of traditional coherent detection.

[0118] Similarly, after receiving the vortex receiving light from the peer optical module, the vortex receiving light is demultiplexed, and the vortex mode light is converted into a Gaussian mode. The second pilot vortex light is converted into the local oscillator light used for coherent detection after being converted into the receiving pilot light, and coherent detection is performed with the demultiplexed signal light.

[0119] The optical receiving component provided in this application can demultiplex the received vortex light into a first sub-received signal light, a second sub-received signal light, and a received pilot light in Gaussian mode through a vortex mode demultiplexing module. The received pilot light is then split using a coupler. The split received pilot light is used as the local oscillator light to perform coherent detection with the third and fourth sub-signal lights, respectively. This enables simultaneous coherent detection of multiple sets of data signals transmitted from the other end, eliminating the influence of frequency offset and phase noise. It eliminates the need for complex carrier recovery algorithms, reducing the complexity, power consumption, and cost of the coherent detection system, and overcoming the limitations of high power consumption, high complexity, and high cost of traditional coherent detection.

[0120] Figure 14 This is a schematic diagram of a self-zero-difference coherent detection system provided in an embodiment of this application. Figure 14As shown in the illustration, this application also provides a self-zero-difference coherent detection system, including a transmitting optical module and a receiving optical module. The transmitting optical module includes an optical transmitting component for transmitting mixed vortex signal light, and the receiving optical module is used to receive the mixed vortex signal light from the transmitting optical module. Pilot light and signal light are obtained by demultiplexing the mixed vortex signal light. The received pilot light is used as the local oscillator light to achieve self-zero-difference coherent transmission, eliminating the influence of frequency offset and phase noise. It eliminates the need for complex carrier recovery algorithms, reducing the complexity, power consumption, and cost of the coherent detection system, and overcoming the limitations of high power consumption, high complexity, and high cost of traditional coherent detection. The optical transmitting component includes a first laser 401 and a first coupler 402 disposed at the optical transmitting end of the first laser 401. The first coupler 402 has multiple output ports, including a first output port, a second output port, and a third output port. The first modulator 403 is connected to the first output terminal of the first coupler 402, and the second modulator 404 is connected to the second output terminal of the first coupler 402. The vortex mode multiplexing module 406 is connected to the third output ports of the first modulator 403, the second modulator 404, and the first coupler 402, respectively, to convert the signal light into a vortex mode and multiplex it into a beam. In this application, the first and second modulators load data onto the signal light, and the light output from the third output port serves as the local oscillator light. The vortex mode multiplexing module 406 converts the emitted light into vortex light with different angular momentum, and transmits the signal light and pilot light using different vortex mode channels.

[0121] The optical receiving component includes: a vortex mode demultiplexing module whose input is connected to the vortex mode multiplexing module 406 via a vortex ring optical fiber, receiving the first vortex emitted light and demultiplexing it into a Gaussian mode third sub-signal light, a fourth sub-signal light, and a received pilot light; a second coupler 502, whose input is used to couple the received pilot light into a first sub-pilot light and a second sub-pilot light; and a third mixer 503, which receives the third sub-signal light and the first sub-pilot light, and mixes them to form a first mixed signal light. The output of the third mixer 503 is connected to a first detector 504. The first detector 504 receives the first mixed signal light, performs balanced detection on the first mixed signal light to convert it into a first electrical signal, and transmits the first electrical signal to a digital processor 310. The digital processor 310 samples the first electrical signal, performs digital signal processing to recover and demodulate the signal, realizing self-zero difference coherent detection based on vortex mode multiplexing. The fourth mixer 505 receives the fourth sub-signal light and the second sub-pilot light, and couples the third sub-signal light and the second sub-pilot light to form a second mixed signal light. The output of the fourth mixer 505 is connected to the second detector 506. The second detector 506 receives the second mixed signal light, performs balanced detection on the second mixed signal light to convert it into a second electrical signal, and transmits the second electrical signal to the digital processor 310. The digital processor 310 samples the second electrical signal, performs digital signal processing to recover and demodulate the signal, realizing self-zero difference coherent detection based on vortex mode multiplexing.

[0122] The first laser outputs Gaussian light, which is split into signal light and pilot light. The signal light, after being modulated and signal-loaded, is divided into N paths. These, along with the pilot light, are converted into N+1 vortex modes by a vortex mode multiplexing module and multiplexed for transmission in a vortex ring fiber. A vortex mode demultiplexing module converts the multiplexed vortex modes into N signal Gaussian beams and one pilot Gaussian beam. The pilot light is then split into N paths and used as the local oscillator light. These, along with the N signal beams, are coherently detected by N coherent receivers, achieving self-zero-difference coherent detection based on vortex mode multiplexing. This invention overcomes the limitations of traditional coherent detection, such as high complexity, high power consumption, and high cost. It has broad application prospects in the fields of vortex mode spatial division multiplexing and short-to-medium distance optical interconnect systems, filling a gap in related technical fields.

[0123] Figure 15 This application provides a schematic diagram of a pilot optical path and signal optical path length alignment module for self-zero difference coherent detection based on vortex mode multiplexing. (See diagram below.) Figure 15As shown, the pilot light path and signal light path length alignment module in self-zero difference coherent detection based on vortex mode multiplexing includes: a first laser 401, a first coupler 402, a first modulator 403, an arbitrary waveform generator 4031, an optical fiber extension line 405, a second sub-coupler 19, a vortex mode multiplexing module 406, a vortex ring fiber 508, a vortex mode demultiplexing module 501, a third coupler 23, a coherent receiver 11, a second laser 13, a fourth coupler 14, a fifth coupler 15, a sixth coupler 16, a third photodetector 17, and a fourth photodetector 18. The first laser 401 outputs Gaussian light to the first modulator 403, and the arbitrary waveform generator 4031 outputs 10 Gbaud. The QPSK signal is modulated into Gaussian light by the first I / Q modulator 403. The first coupler 402 splits the QPSK signal light into two paths. One path of the QPSK signal light passes through the signal light transmission path, including the second I / Q modulator 3, the second sub-coupler 19, the vortex mode multiplexing module 406, the vortex ring fiber 508, and the vortex mode demultiplexing module 501. At this time, the second I / Q modulator 3 is not loaded with an electrical signal. The other path passes through the pilot light transmission path, which includes the fiber extension line 405, the vortex mode multiplexing module 406, the vortex ring fiber 508, the vortex mode demultiplexing module 501, and the third coupler 23. The vortex ring fiber 8 contains N+1 vortex mode multiplexing transmissions. At the receiving end... The second laser 13 outputs Gaussian light as the local oscillator light of the path alignment module. The local oscillator light is split into 2N paths by the fourth coupler 14. The 2N paths of local oscillator light and the 2N paths of QPSK signal light are mixed by 2N couplers from coupler 15 to coupler 16. The 2N photodetectors from photodetector 17 to photodetector 18 convert the mixed light into 2N paths of electrical signals. Each path of electrical signal is sampled and then digital signal processing is performed. The Minn algorithm is used to calculate the difference in the number of symbols between the start bits of a frame of the 2N paths of QPSK symbols. The path mismatch length between the signal light and the pilot light is calculated based on the symbol rate and the light transmission rate in the optical fiber. The optical extension line is adjusted to make the path lengths of the signal light and the pilot light equal.

[0124] Since the above embodiments are all described in conjunction with other methods, and different embodiments have the same parts, the same or similar parts between the various embodiments in this specification can be referred to mutually. They will not be described in detail here.

[0125] It should be noted that in this specification, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a circuit structure, article, or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a circuit structure, article, or device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the circuit structure, article, or device that includes said element.

[0126] Other embodiments of this application will readily conceive of by those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this application are indicated by the content of the claims.

[0127] The embodiments described above do not constitute a limitation on the scope of protection of this application.

Claims

1. An optical module, characterized in that, include: The first laser emits a first emitted light without a signal, and the first emitted light is Gaussian mode light. A first coupler receives the first emitted light and splits the first emitted light into a sub-emitted light and a first pilot light. A first modulator, disposed at the first output port of the first coupler, is used to perform phase modulation on the sub-emitted light to generate sub-signal light; An optical fiber extension line is disposed between the second output port of the first coupler and the vortex mode multiplexing module; The vortex mode multiplexing module has a first input port connected to the output of the first modulator and a second input port connected to the optical fiber extension line. It is used to convert the first pilot light and the sub-signal light into different vortex modes and combine them into a beam of vortex signal emission light.

2. The optical module according to claim 1, characterized in that, The vortex mode multiplexing module includes: A first collimator is connected to the output of the first modulator and is used to collimate the sub-signal light. A first polarizer is disposed on the light-emitting side of the first collimator; A first spatial light modulator, with the polarization direction aligned with the first polarizer, converts the sub-signal light into a first sub-vortex light; The second collimator is connected to the output end of the fiber extension line and is used to collimate the first pilot light. The second polarizer is disposed on the light-emitting side of the second collimator; The second spatial light modulator, with the same polarization direction as the second polarizer, converts the first pilot light into the first pilot vortex light; The first beam combiner is disposed on the output optical path of the first spatial light modulator and the second spatial light modulator, and is used to combine the first pilot vortex light and the first sub-vortex light into a single vortex emission signal light.

3. The optical module according to claim 2, characterized in that, The first spatial light modulator and the second spatial light modulator are reflective spatial light modulators.

4. The optical module according to claim 1, characterized in that, The fiber extension line ensures that the path of the sub-transmitted light through the first coupler and the first modulator to the vortex mode multiplexing module is equal to the path length of the first pilot light from the first coupler to the vortex mode multiplexing module.

5. The optical module according to claim 1, characterized in that, Also includes: The first transmitting fiber is connected to the output end of the vortex mode multiplexing module, and the first transmitting fiber is a vortex ring fiber.

6. The optical module according to claim 5, characterized in that, vortex ring fiber includes: The central region is located at the center of the vortex ring optical fiber; A ring-shaped fiber core covers the outer side of the central region; A cladding layer, covering the outer side of the annular fiber core; The central region has the same refractive index as the cladding; The refractive index of the annular fiber core is greater than that of the cladding.

7. The optical module according to claim 6, characterized in that, The inner diameter of the annular fiber core is 2μm to 10μm, and the width is 1μm to 20μm.

8. The optical module according to claim 1, characterized in that, The vortex mode multiplexing module includes: The first single-mode fiber is connected at one end to the output end of the first modulator and at the other end to one end of the first vortex ring fiber, which converts the sub-signal light from Gaussian mode to vortex mode. The third single-mode fiber is connected at one end to the output end of the fiber delay line; A tapered coupler, with its first input end connected to the other end of the first vortex ring fiber, its second input end connected to the other end of the third single-mode fiber, and its vortex output end connected to the second vortex ring fiber, is used to convert the first pilot light into a vortex mode and to combine the converted sub-signal light and the first pilot light into a single vortex signal emission light.

9. An optical module, characterized in that, include: The first laser emits a first emitted light without a signal, and the first emitted light is Gaussian mode light. The first coupler is a 1×3 coupler that receives the first emitted light and divides the first emitted light into a first sub-emitted light, a second sub-emitted light, and a first pilot light. A first modulator is disposed at the first output port of the first coupler and is used to perform phase modulation on the first sub-emitted light to generate a first sub-signal light; The second modulator is located at the third output port of the first coupler and is used to perform phase modulation on the second sub-emitted light to generate the second sub-signal light. An optical fiber extension line is disposed between the second output port of the first coupler and the vortex mode multiplexing module; The vortex mode multiplexing module has a first input port connected to the output of the first modulator and a second input port connected to the optical fiber extension line. It is used to convert the first pilot light, the first sub-signal light and the second sub-signal light into different vortex modes and combine them into a beam of vortex signal emission light.

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