Optical module

Abstract

The invention provides an optical module which comprises a light source, a coherent optical chip and a controller, the coherent optical chip comprises a first coupling port, an optical splitter group connected with the first coupling port and a wavelength locker connected with one output end of the optical splitter group, and the first coupling port is used for receiving local oscillation light generated by the light source; the optical splitter group is used for dividing the local oscillation light into multiple paths of local oscillation split light; the wavelength locker comprises two waveguides with different optical paths and a multi-mode interference coupler, the wavelength locker divides one path of local oscillator split light into two beams of light, the two beams of light are transmitted through the two waveguides, and the multi-mode interference coupler outputs at least two paths of detection light with different phases; the controller obtains the optical power of the at least two paths of detection light, determines the wavelength of the local oscillation light according to the optical power and a relation curve between the optical power and the wavelength in the controller, and adjusts the wavelength of the local oscillation light output by the light source according to the wavelength difference between the wavelength of the local oscillation light and the preset wavelength. According to the invention, the wavelength locker is integrated in the coherent optical chip, so that the packaging complexity of the light source is reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of optical communication technology, and in particular to an optical module. Background Art

[0002] Optical communication technology is used in new services and application models such as cloud computing, mobile Internet, and video. In optical communication, optical modules are devices that realize photoelectric signal conversion and are one of the key components in optical communication equipment.

[0003] A coherent optical module generally includes a light source and a coherent optical chip. The light source is connected to the coherent optical chip. The light emitted by the light source is incident on the coherent optical chip. The incident light is split inside the coherent optical chip. One beam is used as the transmitted light and enters the coherent modulator in the coherent optical chip to realize the electro-optical signal conversion. The converted optical signal is injected from the optical transmitting interface. The other beam is used as the local oscillator light. The coherent optical chip inputs the optical signal through the optical receiving interface. The local oscillator light is coherently demodulated with the input optical signal to complete the conversion of the optical-electrical signal.

[0004] Currently, the light source of the coherent optical module is a narrow-linewidth, wavelength-adjustable light source, in which a wavelength locking device is integrated. The wavelength locking device is used to monitor the wavelength of light emitted by the laser and perform real-time wavelength locking. However, the packaging process of the light source integrated with the wavelength locking device is complex and expensive. Summary of the invention

[0005] The embodiment of the present disclosure provides an optical module to reduce the packaging complexity of the light source in the coherent optical module, so that the coherent optical module has a wavelength locking function.

[0006] In a first aspect, the present disclosure provides an optical module, comprising:

[0007] Circuit boards;

[0008] A light source, electrically connected to the circuit board, and used to generate local oscillation light;

[0009] A coherent optical chip is electrically connected to the circuit board, and the coherent optical chip includes:

[0010] A first coupling port, optically connected to the light source, the first coupling port being used to input the local oscillator light;

[0011] An optical splitter group, whose input end is connected to the first coupling port, and the optical splitter group is used to split the local oscillator light into multiple local oscillator light splits;

[0012] a wavelength locker connected to an output end of the optical splitter group, the wavelength locker comprising a first waveguide, a second waveguide and a multimode interference coupler, the first waveguide and the second waveguide having different optical paths, and an input end of the multimode interference coupler being respectively connected to the first waveguide and the second waveguide; the wavelength locker is used to split one path of the local oscillator into two beams of light, the two beams of light are transmitted via the first waveguide and the second waveguide, and the multimode interference coupler outputs at least two paths of detection light with different phases;

[0013] A controller is disposed on the circuit board, the controller is electrically connected to the coherent optical chip and the light source respectively, the controller is used to obtain the optical power of the at least two detection lights, determine the wavelength of the local oscillation light according to the optical power and the relationship curve between the optical power and the wavelength stored in the controller, and adjust the wavelength of the local oscillation light output by the light source according to the wavelength difference between the wavelength of the local oscillation light and a preset wavelength to achieve wavelength locking.

[0014] In a second aspect, the present disclosure provides an optical module, including:

[0015] Circuit boards;

[0016] A light source, electrically connected to the circuit board, and used to generate local oscillation light;

[0017] A coherent optical chip is electrically connected to the circuit board, and the coherent optical chip includes:

[0018] A first coupling port, optically connected to the light source, the first coupling port being used to input the local oscillator light;

[0019] An optical splitter group, whose input end is connected to the first coupling port, and the optical splitter group is used to split the local oscillator light into multiple local oscillator light splits;

[0020] A wavelength locker is connected to an output end of the optical splitter group, and the wavelength locker includes:

[0021] A first optical splitter, whose input end is connected to an output end of the optical splitter group, and the first optical splitter is used to split the local oscillator light into a first split light and a second split light;

[0022] A first waveguide connected to a first output end of the first optical splitter, the first waveguide being used to transmit the first split light;

[0023] A second waveguide connected to a second output end of the first optical splitter, the second waveguide being used to transmit the second split light;

[0024] A multimode interference coupler, wherein the output end of the multimode interference coupler comprises four output light ports, so that the first light splitting and the second light splitting interfere with each other to output four detection lights of different phases, wherein the phases differ by 90 degrees respectively;

[0025] A photodetector group, comprising four photodetectors, wherein the photodetectors are used to convert the optical signal of the detection light into an electrical signal;

[0026] A controller is arranged on the circuit board, the controller is electrically connected to the coherent optical chip and the light source respectively, the controller is used to obtain the optical power of the four detection lights, determine the wavelength of the local oscillation light according to the four optical powers and the relationship curve between the optical power and the wavelength stored in the controller, and adjust the wavelength of the local oscillation light output by the light source according to the wavelength difference between the wavelength of the local oscillation light and a preset wavelength to achieve wavelength locking.

[0027] It can be seen from the above embodiments that the optical module provided by the embodiments of the present disclosure includes a circuit board, a light source, a coherent optical chip and a controller. The light source is electrically connected to the circuit board so that the light source generates local oscillation light; the coherent optical chip is electrically connected to the circuit board, and the coherent optical chip includes a first coupling port, a splitter group and a wavelength locker. The first coupling port is connected to the light source to transmit the local oscillation light generated by the light source to the coherent optical chip through the first coupling port; the input end of the splitter group is connected to the first coupling port, and the splitter group is used to split the local oscillation light into multiple local oscillation splits to achieve coherent transmission and reception of the coherent optical chip through the multiple local oscillation splits; the wavelength locker is connected to an output end of the splitter group, and the wavelength locker includes a first waveguide, a second waveguide and a multimode interference coupler. The optical paths of the first waveguide and the second waveguide are different, and the multimode interference coupler The input end is connected to the first waveguide and the second waveguide respectively, and the wavelength locker is used to split a local oscillator into two beams of light, which are transmitted via the first waveguide and the second waveguide, and the multimode interference coupler outputs at least two detection lights of different phases, so as to obtain multiple detection lights of different phases through the wavelength locker; the controller is arranged on the circuit board, and the controller is electrically connected to the coherent optical chip and the light source respectively. The controller obtains the optical power of the multiple detection lights of different phases, determines the wavelength of the local oscillator light according to the multiple optical powers and the relationship curve between the optical power and the wavelength stored in the controller, calculates the wavelength difference between the wavelength of the local oscillator light and the preset wavelength, and the controller feeds back a control signal to the light source according to the wavelength difference to adjust the wavelength of the local oscillator light output by the light source, so that the adjusted wavelength of the local oscillator light reaches the preset wavelength, thereby realizing wavelength locking.

[0028] The present invention integrates a wavelength locker in a coherent optical chip, which can realize accurate monitoring, feedback and locking of the wavelength of the input light of the external light source, so that the external light source does not need to integrate a wavelength locking device, which can reduce the packaging complexity of the external light source. In addition, the coherent optical chip has both coherent transmission and reception functions and integrated wavelength monitoring functions, which can meet short-distance coherent applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the present disclosure, the following briefly introduces the drawings required to be used in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can also be obtained 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 involved in the embodiments of the present disclosure, the actual process of the method, the actual timing of the signal, etc.

[0030] Figure 1 A partial structural diagram of an optical communication system provided according to some embodiments of the present disclosure;

[0031] Figure 2 A partial structural diagram of a host computer provided according to some embodiments of the present disclosure;

[0032] Figure 3 A structural diagram of an optical module provided according to some embodiments of the present disclosure;

[0033] Figure 4 An exploded view of an optical module provided according to some embodiments of the present disclosure;

[0034] Figure 5 A partial structural diagram of an optical module provided according to some embodiments of the present disclosure;

[0035] Figure 6 A schematic diagram of the working principle of an optical module provided according to some embodiments of the present disclosure;

[0036] Figure 7 is a cross-sectional view of a light source in a light module provided according to some embodiments of the present disclosure;

[0037] Figure 8 A structural frame of a coherent optical chip in an optical module provided according to some embodiments of the present disclosure Figure 1 ;

[0038] Fig. 9 A structural frame of a coherent optical chip in an optical module provided according to some embodiments of the present disclosure Figure 2 ;

[0039] Fig.10 A structural frame of a coherent optical chip in an optical module provided according to some embodiments of the present disclosure Figure 3 ;

[0040] Fig.11 A structural frame of a coherent optical chip in an optical module provided according to some embodiments of the present disclosure Figure 4 ;

[0041] Fig.12 A structural frame of a coherent optical chip in an optical module provided according to some embodiments of the present disclosure Figure 5 ;

[0042] Fig.13 A structural diagram of a wavelength locker in an optical module provided according to some embodiments of the present disclosure;

[0043] Fig.14 A power curve diagram of a light detector in an optical module provided according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0044] The following will be combined with the accompanying drawings to clearly and in detail describe the technical solutions in some embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.

[0045] In optical communication technology, in order to establish information transmission between information processing devices, it is necessary to load information onto light and use the propagation of light to achieve information transmission. Here, the light loaded with information is an optical signal. When optical signals are transmitted in information transmission equipment, the loss of optical power can be reduced, so high-speed, long-distance, and low-cost information transmission can be achieved. The signals that information processing equipment can recognize and process are electrical signals. Information processing equipment usually includes optical network terminals (Optical Network Unit, ONU), gateways, routers, switches, mobile phones, computers, servers, tablets, televisions, etc., and information transmission equipment usually includes optical fibers and optical waveguides.

[0046] The optical module can realize the mutual conversion between optical signals and electrical signals between information processing equipment and information transmission equipment. For example, at least one of the optical signal input end or the optical signal output end of the optical module is connected to an optical fiber, and at least one of the electrical signal input end or the electrical signal output end of the optical module is connected to an optical network terminal; the first optical signal from the optical fiber is transmitted to the optical module, and the optical module converts the first optical signal into a first electrical signal, and transmits the first electrical signal to the optical network terminal; the second electrical signal from the optical network terminal is transmitted to the optical module, and the optical module converts the second electrical signal into a second optical signal, and transmits the second optical signal to the optical fiber. Since multiple information processing devices can transmit information through electrical signals, at least one of the multiple information processing devices needs to be directly connected to the optical module, and all information processing devices do not need to be directly connected to the optical module. Here, the information processing device directly connected to the optical module is called the upper computer of the optical module. In addition, the optical signal input end or the optical signal output end of the optical module can be called an optical port, and the electrical signal input end or the electrical signal output end of the optical module can be called an electrical port.

[0047] Figure 1 FIG. 1 is a partial structural diagram of an optical communication system provided according to some embodiments of the present disclosure. Figure 1 As shown, the optical communication system mainly includes a remote information processing device 1000 , a local information processing device 2000 , a host computer 100 , an optical module 200 , an optical fiber 101 and a network cable 103 .

[0048] One end of the optical fiber 101 extends toward the remote information processing device 1000, and the other end of the optical fiber 101 is connected to the optical module 200 through the optical port of the optical module 200. The optical signal can be totally reflected in the optical fiber 101, and the propagation of the optical signal in the total reflection direction can almost maintain the original optical power. The optical signal undergoes multiple total reflections in the optical fiber 101 to transmit the optical signal from the remote information processing device 1000 to the optical module 200, or to transmit the optical signal from the optical module 200 to the remote information processing device 1000, thereby realizing long-distance, low-power loss information transmission.

[0049] The optical communication system may include one or more optical fibers 101, and the optical fibers 101 are detachably connected or fixedly connected to the optical module 200. The host computer 100 is configured to provide data signals to the optical module 200, receive data signals from the optical module 200, or monitor or control the working state of the optical module 200.

[0050] The host computer 100 includes a substantially rectangular housing and an optical module interface 102 disposed on the housing. The optical module interface 102 is configured to connect to the optical module 200 so that the host computer 100 and the optical module 200 establish a unidirectional or bidirectional electrical signal connection.

[0051] The host computer 100 also includes an external electrical interface, which can be connected to an electrical signal network. For example, the external electrical interface includes a Universal Serial Bus (USB) interface or a network cable interface 104, and the network cable interface 104 is configured to access the network cable 103 so that the host computer 100 establishes a unidirectional or bidirectional electrical signal connection with the network cable 103. One end of the network cable 103 is connected to the local information processing device 2000, and the other end of the network cable 103 is connected to the host computer 100, so as to establish an electrical signal connection between the local information processing device 2000 and the host computer 100 through the network cable 103. For example, the third electrical signal sent by the local information processing device 2000 is transmitted to the host computer 100 through the network cable 103, and the host computer 100 generates a second electrical signal according to the third electrical signal. The second electrical signal from the host computer 100 is transmitted to the optical module 200, and the optical module 200 converts the second electrical signal into a second optical signal, and transmits the second optical signal to the optical fiber 101, and the second optical signal is transmitted to the remote information processing device 1000 in the optical fiber 101. For example, the first optical signal from the remote information processing device 1000 is transmitted through the optical fiber 101, and the first optical signal from the optical fiber 101 is transmitted to the optical module 200, and the optical module 200 converts the first optical signal into a first electrical signal, and the optical module 200 transmits the first electrical signal to the host computer 100, and the host computer 100 generates a fourth electrical signal according to the first electrical signal, and transmits the fourth electrical signal to the local information processing device 2000. It should be noted that the optical module is a tool for realizing the mutual conversion between optical signals and electrical signals. During the conversion process between the optical signals and electrical signals, the information does not change, but the encoding and decoding methods of the information can change.

[0052] In addition to the optical network terminal, the host computer 100 also includes an optical line terminal (OLT), an optical network device (ONT), or a data center server.

[0053] Figure 2 1 is a partial structural diagram of a host computer provided according to some embodiments of the present disclosure. In order to clearly show the connection relationship between the optical module 200 and the host computer 100, Figure 2 Only the structure of the host computer 100 related to the optical module 200 is shown. Figure 2 As shown, the host computer 100 further includes a PCB circuit board 105 disposed in the housing, a cage 106 disposed on the surface of the PCB circuit board 105, a heat sink 107 disposed on the cage 106, and an electrical connector disposed inside the cage 106. The electrical connector is configured to access the electrical port of the optical module 200; the heat sink 107 has a protruding structure such as fins to increase the heat dissipation area.

[0054] The optical module 200 is inserted into the cage 106 of the host computer 100, and the cage 106 fixes the optical module 200. The heat generated by the optical module 200 is transferred to the cage 106 and then diffused through the heat sink 107. After the optical module 200 is inserted into the cage 106, the electrical port of the optical module 200 is connected to the electrical connector inside the cage 106, so that the optical module 200 establishes a bidirectional electrical signal connection with the host computer 100. In addition, the optical port of the optical module 200 is connected to the optical fiber 101, so that the optical module 200 establishes a bidirectional optical signal connection with the optical fiber 101.

[0055] Figure 3 is a structural diagram of an optical module provided according to some embodiments of the present disclosure, Figure 4 FIG. 1 is an exploded view of an optical module provided according to some embodiments of the present disclosure. Figure 3 and Figure 4 As shown, the optical module 200 includes a shell, a circuit board 300 disposed in the shell, a light source, a coherent optical chip 1100, a transmitting optical fiber adapter 700 and a receiving optical fiber adapter 800, but the present disclosure is not limited thereto.

[0056] The housing comprises an upper housing 201 and a lower housing 202 . The upper housing 201 covers the lower housing 202 to form the housing having two openings 204 and 205 . The outer contour of the housing is generally a square body.

[0057] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 located on both sides of the bottom plate 2021 and arranged perpendicular to the bottom plate 2021; the upper shell 201 includes a cover plate 2011, and the cover plate 2011 covers the two lower side plates 2022 of the lower shell 202 to form the above-mentioned shell.

[0058] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 located on both sides of the bottom plate 2021 and vertically arranged with the bottom plate 2021; the upper shell 201 includes a cover plate 2011 and two upper side plates located on both sides of the cover plate 2011 and vertically arranged with the cover plate 2011, and the two upper side plates are combined with the two lower side plates 2022 to realize that the upper shell 201 covers the lower shell 202.

[0059] The direction of the line connecting the two openings 204 and 205 may be consistent with the length direction of the optical module 200, or may be inconsistent with the length direction of the optical module 200. For example, the 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 ( Figure 3Alternatively, the opening 204 is located at the end of the optical module 200, and the opening 205 is located at the side of the optical module 200. The opening 204 is an electrical port, and the gold finger of the circuit board 300 extends from the electrical port and is inserted into the electrical connector of the host computer 100; the opening 205 is an optical port, which is configured to access the external optical fiber 101 so that the optical fiber 101 is connected to the coherent optical chip 1100 in the optical module 200.

[0060] The assembly method of combining the upper housing 201 and the lower housing 202 is adopted, so that the circuit board 300, the light source, the coherent optical chip 1100, the transmitting optical fiber adapter 700, the receiving optical fiber adapter 800, etc. can be installed in the above housing, and the upper housing 201 and the lower housing 202 can encapsulate and protect the above components. In addition, when assembling the circuit board 300, the light source, the coherent optical chip 1100, the transmitting optical fiber adapter 700, the receiving optical fiber adapter 800, etc., the assembly method of the upper housing 201 and the lower housing 202 is adopted, which is convenient for the deployment of the positioning components, heat dissipation components and electromagnetic shielding components of these components, and is conducive to the automated production.

[0061] In some embodiments, the upper shell 201 and the lower shell 202 are made of metal materials to facilitate electromagnetic shielding and heat dissipation.

[0062] In some embodiments, the optical module 200 further includes an unlocking component 600 located outside its housing. The unlocking component 600 is configured to achieve a fixed connection between the optical module 200 and the host computer 100, or to release the fixed connection between the optical module 200 and the host computer 100.

[0063] For example, the unlocking component 600 is located on the outside of the two lower side plates 2022 of the lower housing 202, and includes a snap-fit ​​component that matches the cage 106 of the host computer 100. When the optical module 200 is inserted into the cage 106, the snap-fit ​​component of the unlocking component 600 fixes the optical module 200 in the cage 106; when the unlocking component 600 is pulled, the snap-fit ​​component of the unlocking component 600 moves accordingly, thereby changing the connection relationship between the snap-fit ​​component and the host computer, so as to release the fixation of the optical module 200 and the host computer, so that the optical module 200 can be pulled out of the cage 106.

[0064] The circuit board 300 includes circuit traces, electronic components and chips, etc. The electronic components and chips are connected according to the circuit design through the circuit traces to realize the functions of power supply, electrical signal transmission and grounding. The electronic components may include capacitors, resistors, transistors, metal-oxide-semiconductor field-effect transistors (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET), etc. The chips may include microcontroller units (Microcontroller Unit, MCU), laser driver chips, transimpedance amplifiers (Transimpedance Amplifier, TIA), limiting amplifiers (Limiting amplifier, LA), clock and data recovery chips (Clock and Data Recovery, CDR), power management chips, digital signal processing (Digital Signal Processing, DSP) chips.

[0065] The circuit board 300 is generally a rigid circuit board. Due to its relatively hard material, the rigid circuit board can also realize the load-bearing function. For example, the rigid circuit board can stably carry the above-mentioned electronic components and chips; the rigid circuit board can also be inserted into the electrical connector in the cage 106 of the host computer 100.

[0066] The circuit board 300 also includes a gold finger formed on the end surface thereof, and the gold finger is composed of a plurality of independent pins. The circuit board 300 is inserted into the cage 106, and the gold finger is connected to the electrical connector in the cage 106. The gold finger can be provided on the surface of only one side of the circuit board 300 (for example, Figure 4 The upper surface shown in the figure) can also be set on the upper and lower surfaces of the circuit board 300 to provide a larger number of pins, so as to adapt to occasions where the number of pins is large. The gold finger is configured to establish an electrical connection with the host computer to achieve power supply, grounding, two-wire synchronous serial (Inter-Integrated Circuit, I2C) signal transmission, data signal transmission, etc. Of course, flexible circuit boards are also used in some optical modules. Flexible circuit boards are generally used in conjunction with rigid circuit boards to supplement rigid circuit boards.

[0067] In some embodiments, the light source and the coherent optical chip 1100 are physically separated from the circuit board 300 and then electrically connected to the circuit board 300 via a flexible circuit board or an electrical connector.

[0068] In some embodiments, the light source and the coherent optical chip 1100 may be directly disposed on the circuit board 300. For example, the light source and the coherent optical chip 1100 may be disposed on the surface of the circuit board 300 or on the side of the circuit board 300.

[0069] Figure 5 is a partial structural diagram of an optical module provided according to some embodiments of the present disclosure, Figure 6 FIG. 1 is a schematic diagram of the working principle of an optical module provided according to some embodiments of the present disclosure. Figure 5 and Figure 6 As shown, the coherent optical chip 1100 is a coherent silicon optical integrated chip. Since the silicon material in the silicon optical chip is not an ideal laser chip light-emitting material, the light-emitting unit cannot be integrated in the silicon optical chip manufacturing process, so the silicon optical chip needs to be provided with light by an external light source. Exemplarily, the laser assembly 900 is used as an external light source to provide light for the silicon optical chip.

[0070] The coherent optical chip 1100 includes three external optical fiber interfaces, namely a first coupling port (local oscillator optical interface), a second coupling port (optical receiving interface) and a third coupling port (optical transmitting interface). The optical transmitting interface and the optical receiving interface are respectively connected to the two external optical fiber interfaces of the coherent optical module, and the local oscillator optical interface is connected to the laser component 900 through a polarization-maintaining optical fiber.

[0071] A digital signal processing chip 302, a driver chip 304 and an amplifier chip 305 are provided on the circuit board 300. The digital signal processing chip 302 is connected to the coherent optical chip 1100 through the driver chip 304 and the amplifier chip 305, that is, the digital signal processing chip 302 applies a high-speed modulated electrical signal to the modulator in the coherent optical chip 1100 through the driver chip 304, so that the coherent optical chip 1100 generates a coherent emission optical signal; the digital signal processing chip 302 receives the receiving electrical signal fed back by the coherent optical chip 1100 through the amplifier chip 305, and the digital signal processing chip 302 demodulates the electrical signal to realize the reception of the coherent optical signal.

[0072] The working principle of the coherent optical module is as follows: the narrow line width and high power laser emitted by the laser assembly 900 is coupled to the coherent optical chip 1100 through the local oscillator optical interface, and the laser is subjected to beam splitting processing inside the coherent optical chip 1100, wherein one beam of light enters the coherent modulator inside the coherent optical chip 1100 as the emission light, and the electrical-optical signal conversion is realized under the high-speed electrical signal drive of the digital signal processing chip 302, and the converted high-speed optical signal is output from the optical emission interface, and the optical signal is transmitted to the emission optical fiber adapter 700 through the emission optical fiber, and is emitted through the emission optical fiber adapter 700 to realize the emission of coherent light.

[0073] The external optical signal transmitted by the receiving optical fiber adapter 800 is emitted into the coherent optical chip 1100 via the receiving optical fiber and the optical receiving interface. Another beam of light is used as the local oscillator light to be coherently demodulated with the external optical signal. The demodulated electrical signal enters the digital signal processing chip 302 for signal processing to complete the conversion of the optical and electrical signals, thereby realizing the reception of coherent light.

[0074] In some embodiments, the laser component 900 used in the coherent optical module is a narrow-linewidth wavelength-tunable laser component, and a wavelength locking device is integrated inside the laser component. The wavelength locking device is used to monitor the wavelength of light emitted by the laser and perform real-time wavelength locking. However, the packaging process of the laser component is complex and expensive, which is not conducive to short-distance coherent applications.

[0075] In order to solve the above problems, an embodiment of the present disclosure provides an optical module, which integrates a wavelength locking device inside the coherent optical chip 1100. The wavelength locking device can monitor the wavelength of light emitted by the external laser component 900 in real time, and generate a feedback signal to the external laser component to adjust and lock the preset wavelength, thereby simplifying the packaging complexity and cost of the external laser component 900 and meeting the use requirements of short-distance coherent optical modules.

[0076] Figure 7 1 is a cross-sectional view of a light source in a light module provided according to some embodiments of the present disclosure. Figure 7 As shown, the laser assembly 900 includes a shell 901 and a cover plate, which is covered in the shell 901 so that the shell 901 and the cover plate form a cavity; the shell 901 includes a bottom plate and a first side plate, a second side plate, and a third side plate connected to the bottom plate, the first side plate and the second side plate are arranged opposite to each other, the third side plate is the right side plate of the shell 901, the left side of the shell 901 is provided with an opening, and the top surface of the shell 901 is provided with an opening.

[0077] A boss 909 is provided on the left side of the shell 901, and the boss 909 is installed on the bottom plate of the shell 901. The boss 909 is arranged opposite to the third side plate. A adapter circuit board 910 is provided on the surface of the boss 909. One end of the adapter circuit board 910 is located in the accommodating cavity of the shell 901, and the other end of the adapter circuit board 910 is located outside the accommodating cavity. The end of the adapter circuit board 910 located outside the accommodating cavity is electrically connected to the circuit board 300 through wiring or a flexible circuit board, so that the driving electrical signal emitted by the circuit board 300 is transmitted to the laser 902 through the adapter circuit board, and the laser 902 emits light under the action of the driving electrical signal.

[0078] A through hole 911 is formed on the third side plate, and an optical fiber connector 920 is disposed in the through hole 911. The optical fiber connector 920 is coupled to the light source optical fiber, and the light source optical fiber is a polarization-maintaining optical fiber to achieve the coupling connection between the laser assembly 900 and the light source optical fiber.

[0079] In some embodiments, a TEC 907 and a carrier board 908 are disposed in the accommodating cavity of the shell 901, and a laser 902 and a collimating lens 903 are disposed on the surface of the TEC 907. The laser 902 receives a driving electrical signal transmitted by the circuit board 300 through the adapter circuit board 910, so that the laser 902 generates a laser that does not carry data; the collimating lens 903 is located in the light emitting direction of the laser 902, and the collimating lens 903 converts the laser generated by the laser 902 into parallel light.

[0080] In coherent communication, the wavelength difference (or frequency difference) between the received optical signal and the local oscillator optical signal needs to be less than a certain value to produce interference and ensure that the digital signal processing chip 302 can process the response signal. Therefore, the wavelength of the laser 902 needs to be kept in a very stable state. Therefore, TEC907 is used as a key temperature control element to control the wavelength of the laser 902, and a high-precision temperature sensor is used to detect the temperature of the laser 902.

[0081] In some embodiments, a focusing lens 905 is disposed on the surface of the carrier 908 , and the parallel light emitted by the collimating lens 903 is focused to the light source fiber in the optical fiber connector 920 via the focusing lens 905 to couple the laser generated by the laser 902 to the light source fiber.

[0082] Due to the difference in transmission media, the convergent light emitted by the converging lens 905 is easily reflected at the fiber end face of the light source optical fiber. In order to prevent the reflected light from returning to the laser 902 along the original path, an optical isolator 904 is also provided on the surface of the carrier 908. The optical isolator 904 is located between the collimating lens 903 and the converging lens 905. The parallel light emitted by the collimating lens 903 directly passes through the optical isolator 904 and enters the converging lens 905. The parallel light is converged to the light source optical fiber via the converging lens 905. The reflected light at the fiber end face is isolated by the optical isolator 904 and cannot pass through the optical isolator 904 to return to the laser 902, thereby ensuring the luminous performance of the laser 902.

[0083] In some embodiments, the carrier plate 908 is used to raise the height of the optical isolator 904 and the converging lens 905 so that the optical axes of the optical isolator 904 and the converging lens 905, the optical axis of the laser 902, and the optical axis of the collimating lens 903 are on the same straight line, so as to facilitate coupling the laser generated by the laser 902 to the light source optical fiber.

[0084] In some embodiments, when performing optical coupling of the laser assembly 900, it is necessary to consider the subsequent installation direction of the laser assembly 900 on the circuit board 300 and modulate the placement of the light source optical fiber to avoid twisting of the light source optical fiber when the laser assembly 900 is installed on the module circuit board 300.

[0085] Figure 8A structural frame of a coherent optical chip in an optical module provided according to some embodiments of the present disclosure Figure 1 .like Figure 6 and Figure 8 As shown, the optical module provided by the embodiment of the present disclosure includes a circuit board 300, a laser component 900 and a coherent optical chip 1100. The laser component 900 and the coherent optical chip 1100 are installed on the circuit board 300. A controller 303 is also provided on the circuit board 300. The laser component 900 is connected to the coherent optical chip 302 through a polarization-maintaining optical fiber to input local oscillation light to the coherent optical chip 302; the coherent optical chip 302 is electrically connected to the controller 303 to feed back an electrical signal to the controller 303; the controller 303 is control-connected to the laser component 900 to send a control signal to the laser component 900 according to the feedback electrical signal received by the controller 303, thereby controlling the wavelength of the laser generated by the laser component 900.

[0086] In order to receive the local oscillator light generated by the laser assembly 900, the coherent optical chip 1100 includes a first coupling port 1101, a second coupling port 1102 and a third coupling port 1103. The first coupling port 1101 is a local oscillator light interface, the second coupling port 1102 is a receiving coupling port, and the third coupling port 1103 is a transmitting coupling port. The first coupling port 1101, the second coupling port 1102 and the third coupling port 1103 are packaged with a three-channel optical fiber array to realize the interconnection between the coherent optical chip 1100 and the external optical signal.

[0087] Among them, the first coupling port 1101 is connected to the laser component 900 through a polarization-maintaining optical fiber, and the light of a preset wavelength emitted by the external laser component 900 enters the coherent optical chip 1100 through the first coupling port 1101; the second coupling port 1102 is connected to the receiving optical fiber adapter 800 through a receiving optical fiber, so that the external optical signal transmitted by the receiving optical fiber adapter 800 is transmitted to the coherent optical chip 1100 via the second coupling port 1102; the third coupling port 1103 is connected to the transmitting optical fiber adapter 700 through a transmitting optical fiber, so that the transmitting optical signal generated by the coherent optical chip 302 is transmitted to the transmitting optical fiber adapter 700 via the third coupling port 1103, and then emitted through the transmitting optical fiber adapter 700.

[0088] The coherent optical chip 1100 is integrated with a beam splitter group, and the input end of the beam splitter group is connected to the first coupling port 1101. After the local oscillator light emitted by the laser assembly 900 enters the coherent optical chip 1100, the local oscillator light is split into three parts of light by the beam splitter group. One part of the light enters the dual-coherent modulator as the emission light, and is modulated into an orthogonal signal light after being loaded by the electro-optical signal (wherein the electrical signal is emitted by the digital signal processing chip 302 and loaded onto the coherent optical chip 1100 after passing through the driving chip 304). The orthogonal signal light is polarized by the emission polarization rotation combiner, and then the processed orthogonal signal light is output from the third coupling port to realize the emission of coherent light.

[0089] Another part of the light, as the local oscillator light, is split again and enters the dual polarization balanced detector respectively, and is mixed with the light input from the second coupling port 1102 and processed by the receiving polarization rotation beam splitter, so as to realize the demodulation of the optical signal. The demodulated electrical signal is input to the amplifier chip 305 through the high-speed detector, and the electrical signal is input to the digital signal processing chip 302 for processing after amplification to realize the reception of coherent light.

[0090] The coherent optical chip 1100 is integrated with a wavelength locker 1106, which is connected to an output end of the splitter group, that is, the third part of the light enters the wavelength locker 1106, and the wavelength locker 1106 can detect the wavelength of the incoming light. The wavelength locker 1106 transmits the detected electrical signal to the controller 303, and the controller 303 calculates the wavelength difference between the detected wavelength and the preset wavelength according to the detected electrical signal. The controller 303 feeds back a control signal to the laser component 900 according to the wavelength difference to adjust the wavelength of the laser generated by the laser component 900, so as to stabilize the wavelength of the laser generated by the laser component 900 at the preset wavelength to achieve wavelength locking.

[0091] In some embodiments, the splitter group includes a directional coupler 1104, a second splitter 1105 and a third splitter 1107. The input end of the directional coupler 1104 can be connected to the first coupling port 1101. The directional coupler 1104 splits the local oscillator light incident from the first coupling port 1101 into a first local oscillator light and a second local oscillator light. The first local oscillator light and the second local oscillator light have the same wavelength and frequency.

[0092] The input end of the second optical splitter 1105 is connected to the first output end of the directional coupler 1104, so that the first local oscillator light is input to the second optical splitter 1105. The wavelength locker 1106 is connected to the second output end of the directional coupler 1104 to input the second local oscillator light into the wavelength locker 1106. The wavelength locker 1106 detects the second local oscillator light. The controller 303 receives the electrical signal detected by the wavelength locker 1106, and determines the wavelength of the second local oscillator light according to the detected electrical signal, thereby calculating the wavelength difference between the wavelength of the second local oscillator light and the preset wavelength. The controller 303 controls and adjusts the wavelength of the laser emitted by the laser component 900 according to the wavelength difference, thereby stabilizing the wavelength of the laser emitted by the laser component 900 at the preset wavelength.

[0093] The second optical splitter 1105 splits the first local oscillator light into the first local oscillator light and the second local oscillator light. The first local oscillator light enters the fourth optical splitter 1115 as the local oscillator light. The fourth optical splitter 1115 splits the first local oscillator light into two beams of light. The two beams of light enter the first mixer 1112 and the second mixer 1113 respectively. The received light injected from the second coupling port 1102 is divided into two beams of light by the receiving polarization rotation beam splitter. The two beams of light enter the first mixer 1112 and the second mixer 1113 respectively. The local oscillator light and the received light are mixed by the mixer, thereby realizing the demodulation processing of the optical signal. Then, the demodulated electrical signal is input to the amplifier chip 305 through the first high-speed detector group 1116 and the second high-speed detector group 1114 respectively. After amplification, the electrical signal is input to the digital signal processing chip 302 for electrical signal processing, thereby realizing the reception of coherent light.

[0094] The second local oscillator is split into two beams of light by the third beam splitter 1107, and the third beam splitter 1107 splits the second local oscillator into two beams of light. The two beams of light enter the first orthogonal coherent modulator 1108 and the second orthogonal coherent modulator 1109 respectively. The two beams of light are loaded with electro-optical signals in the first orthogonal coherent modulator 1108 and the second orthogonal coherent modulator 1109 to obtain two orthogonal signal lights. The two orthogonal signal lights are transmitted through the emission polarization rotation beam splitter 1110 to obtain one signal light, and one signal light is emitted from the third coupling port 1103, thereby realizing the emission of coherent light.

[0095] In some embodiments, the wavelength locker 1106 receives a local oscillator light split by the directional coupler 1104 in the splitter group, and the wavelength locker 1106 outputs at least two detection lights from the local oscillator light split. The controller 303 determines the wavelength of the local oscillator light split according to the optical power of the at least two detection lights and the relationship curve between the optical power and the wavelength stored in the controller 303. However, the wavelength locker 1106 is not limited to being connected to one output end of the directional coupler 1104, as long as the wavelength locker 1106 can receive one local oscillator light split.

[0096] Fig. 9 A structural frame of a coherent optical chip in an optical module provided according to some embodiments of the present disclosure Figure 2 .like Fig. 9 As shown, the optical splitter group includes a second optical splitter 1105, a directional coupler 1104 and a third optical splitter 1107. The input end of the second optical splitter 1105 is connected to the first coupling port 1101 to receive the local oscillation light output by the laser assembly 900; the second optical splitter 1105 splits the local oscillation light into a first local oscillation light and a second local oscillation light, and the first local oscillation light enters the fourth optical splitter 1115 as the local oscillation light, and the fourth optical splitter 1115 splits the first local oscillation light into two beams of light, and the two beams of light enter the first mixer 1112 and the second mixer 1113 respectively. 13; The received light incident from the second coupling port 1102 is divided into two beams of light by the receiving polarization rotation beam splitter, and the two beams of light enter the first mixer 1112 and the second mixer 1113 respectively. The local oscillator light and the received light are mixed by the mixer, thereby realizing the demodulation processing of the optical signal, and then the demodulated electrical signal is input to the amplifier chip 305 through the first high-speed detector group 1116 and the second high-speed detector group 1114 respectively. After the electrical signal is amplified, it is input to the digital signal processing chip 302 for electrical signal processing, thereby realizing the reception of coherent light.

[0097] The input end of the directional coupler 1104 is connected to the second output end of the second spectrometer 1105, the second local oscillator light enters the directional coupler 1104, the directional coupler 1104 splits the second local oscillator light into the first local oscillator light and the second local oscillator light, the wavelength locker 1106 is connected to the first output end of the directional coupler 1104, so that the first local oscillator light enters the wavelength locker 1106, the wavelength locker 1106 detects the first local oscillator light, so that the wavelength locker 1106, the controller 303 and the laser assembly 900 form a closed-loop control to achieve wavelength locking.

[0098] The input end of the third optical splitter 1107 is connected to the second output end of the directional coupler 1104. The third optical splitter 1107 splits the second local oscillator into two light beams. The two light beams enter the first orthogonal coherent modulator 1108 and the second orthogonal coherent modulator 1109 respectively. The two light beams are loaded with electro-optical signals in the first orthogonal coherent modulator 1108 and the second orthogonal coherent modulator 1109 to obtain two orthogonal signal lights. The two orthogonal signal lights are transmitted through the emission polarization rotation beam splitter 1110 to obtain one signal light. The one signal light is emitted from the third coupling port 1103, thereby realizing the emission of coherent light.

[0099] Fig.10 A structural frame of a coherent optical chip in an optical module provided according to some embodiments of the present disclosure Figure 3 .like Fig.10As shown, the optical splitter group includes a second optical splitter 1105, a directional coupler 1104 and a third optical splitter 1107. The input end of the second optical splitter 1105 is connected to the first coupling port 1101 to receive the local oscillator light output by the laser assembly 900; the second optical splitter 1105 splits the local oscillator light into a first local oscillator light and a second local oscillator light, and the input end of the directional coupler 1104 is connected to the first output end of the second optical splitter 1105, so that the first local oscillator light enters the directional coupler 1104; the directional coupler 1104 splits the first local oscillator light into a first local oscillator light and a second local oscillator light, and the first local oscillator light enters the fourth optical splitter 1115 as the local oscillator light, and the fourth optical splitter 1115 The optical device 1115 splits the first local oscillator light into two beams, and the two beams enter the first mixer 1112 and the second mixer 1113 respectively; the received light injected from the second coupling port 1102 is divided into two beams by the receiving polarization rotation beam splitter, and the two beams enter the first mixer 1112 and the second mixer 1113 respectively, and the local oscillator light and the received light are mixed by the mixer, thereby realizing the demodulation processing of the optical signal, and then the demodulated electrical signal is input to the amplifier chip 305 through the first high-speed detector group 1116 and the second high-speed detector group 1114 respectively, and the electrical signal is input to the digital signal processing chip 302 for electrical signal processing after amplification, thereby realizing the reception of coherent light.

[0100] The wavelength locker 1106 is connected to the second output end of the directional coupler 1104, so that the second local oscillator light splitting enters the wavelength locker 1106. The wavelength locker 1106 detects the second local oscillator light splitting, so that the wavelength locker 1106, the controller 303 and the laser assembly 900 form a closed-loop control to achieve wavelength locking.

[0101] The input end of the third spectrometer 1107 is connected to the second output end of the second spectrometer 1105, so that the second local oscillator light enters the third spectrometer 1107, and the third spectrometer 1107 splits the second local oscillator light into two beams of light. The two beams of light enter the first orthogonal coherent modulator 1108 and the second orthogonal coherent modulator 1109 respectively. After the two beams of light are loaded with electro-optical signals in the first orthogonal coherent modulator 1108 and the second orthogonal coherent modulator 1109, two orthogonal signal lights are obtained. The two orthogonal signal lights are transmitted through the emission polarization rotation beam splitter 1110 to obtain one signal light, and one signal light is emitted from the third coupling port 1103, thereby realizing the emission of coherent light.

[0102] Fig.11 A structural frame of a coherent optical chip in an optical module provided according to some embodiments of the present disclosure Figure 4 .like Fig.11As shown, the optical splitter group includes a second optical splitter 1105, a third optical splitter 1107 and a directional coupler 1104. The input end of the second optical splitter 1105 is connected to the first coupling port 1101 to receive the local oscillation light output by the laser assembly 900; the second optical splitter 1105 splits the local oscillation light into a first local oscillation light and a second local oscillation light, and the first local oscillation light enters the fourth optical splitter 1115 as the local oscillation light, and the fourth optical splitter 1115 splits the first local oscillation light into two beams of light, and the two beams of light enter the first mixer 1112 and the second mixer 1113 respectively. 13; The received light incident from the second coupling port 1102 is divided into two beams of light by the receiving polarization rotation beam splitter, and the two beams of light enter the first mixer 1112 and the second mixer 1113 respectively. The local oscillator light and the received light are mixed by the mixer, thereby realizing the demodulation processing of the optical signal, and then the demodulated electrical signal is input to the amplifier chip 305 through the first high-speed detector group 1116 and the second high-speed detector group 1114 respectively. After the electrical signal is amplified, it is input to the digital signal processing chip 302 for electrical signal processing, thereby realizing the reception of coherent light.

[0103] The input end of the third spectrometer 1107 is connected to the second output end of the second spectrometer 1105, so that the second local oscillator light enters the third spectrometer 1107, and the third spectrometer 1107 splits the second local oscillator light into two beams; the input end of the directional coupler 1104 is connected to the first output end of the third spectrometer 1107, so that a beam of light enters the directional coupler 1104, and the directional coupler 1104 splits the beam of light into a first local oscillator light and a second local oscillator light, and the first local oscillator light enters the wavelength locker 1106, and the wavelength locker 1106 detects the first local oscillator light, so that the wavelength locker 1106, the controller 303 and the laser assembly 900 form a closed-loop control to achieve wavelength locking.

[0104] Another beam of light output from the second output end of the third optical splitter 1107 enters the first orthogonal coherent modulator 1108, and the second local oscillator splits the light and enters the second orthogonal coherent modulator 1109. The two beams of light are loaded with electro-optical signals in the first orthogonal coherent modulator 1108 and the second orthogonal coherent modulator 1109 to obtain two orthogonal signal lights. The two orthogonal signal lights are passed through the emission polarization rotation beam splitter 1110 to obtain one signal light, and one signal light is emitted from the third coupling port 1103, thereby realizing the emission of coherent light.

[0105] Fig.12 A structural frame of a coherent optical chip in an optical module provided according to some embodiments of the present disclosure Figure 5 .like Fig.12As shown, the optical splitter group includes a second optical splitter 1105, a third optical splitter 1107 and a directional coupler 1104. The input end of the second optical splitter 1105 is connected to the first coupling port 1101 to receive the local oscillation light output by the laser assembly 900; the second optical splitter 1105 splits the local oscillation light into a first local oscillation light and a second local oscillation light, and the first local oscillation light enters the fourth optical splitter 1115 as the local oscillation light, and the fourth optical splitter 1115 splits the first local oscillation light into two beams of light, and the two beams of light enter the first mixer 1112 and the second mixer 1113 respectively. 13; The received light incident from the second coupling port 1102 is divided into two beams of light by the receiving polarization rotation beam splitter, and the two beams of light enter the first mixer 1112 and the second mixer 1113 respectively. The local oscillator light and the received light are mixed by the mixer, thereby realizing the demodulation processing of the optical signal, and then the demodulated electrical signal is input to the amplifier chip 305 through the first high-speed detector group 1116 and the second high-speed detector group 1114 respectively. After the electrical signal is amplified, it is input to the digital signal processing chip 302 for electrical signal processing, thereby realizing the reception of coherent light.

[0106] The input end of the third spectrometer 1107 is connected to the second output end of the second spectrometer 1105, so that the second local oscillator light enters the third spectrometer 1107, and the third spectrometer 1107 splits the second local oscillator light into two beams; the input end of the directional coupler 1104 is connected to the second output end of the third spectrometer 1107, so that a beam of light enters the directional coupler 1104, and the directional coupler 1104 splits the beam of light into a first local oscillator light and a second local oscillator light, and the first local oscillator light enters the wavelength locker 1106, and the wavelength locker 1106 detects the first local oscillator light, so that the wavelength locker 1106, the controller 303 and the laser assembly 900 form a closed-loop control to achieve wavelength locking.

[0107] The second local oscillator splits the light and enters the first orthogonal coherent modulator 1108. Another light beam output from the first output end of the third optical splitter 1107 enters the second orthogonal coherent modulator 1109. The two light beams are loaded with electro-optical signals in the first orthogonal coherent modulator 1108 and the second orthogonal coherent modulator 1109 to obtain two orthogonal signal lights. The two orthogonal signal lights are passed through the emission polarization rotation beam splitter 1110 to obtain one signal light, which is emitted from the third coupling port 1103, thereby realizing the emission of coherent light.

[0108] In some embodiments, the splitting ratio of the directional coupler 1104 is 96:4, the splitting ratio of the second splitter 1105 is 75:25, the splitting ratio of the third splitter 1107 is 50:50, and the splitting ratio of the fourth splitter 1115 is 50:50.

[0109] Fig.13FIG. 1 is a structural diagram of a wavelength locker in an optical module according to some embodiments of the present disclosure. Fig.13 As shown, in order to enable the wavelength locker 1106 to detect the wavelength of the local oscillator light injected into the coherent optical chip 1100, the wavelength locker 1106 includes a first optical splitter 1120, a first waveguide 1122, a second waveguide 1124, a multimode interference coupler 1125 and a photodetector group, wherein:

[0110] The first optical splitter 1120 has an input end connected to the second output end of the directional coupler 1104 . The first optical splitter 1120 is used to split the second local oscillator light output by the directional coupler 1104 into a first light split and a second light split.

[0111] One end of the first waveguide 1122 is connected to the first output end of the first optical splitter 1120 , and the first waveguide 1122 is used to transmit the first split light.

[0112] The second waveguide 1124 has one end connected to the second output end of the first optical splitter 1120. The optical path of the second waveguide 1124 is greater than the optical path of the first waveguide 1122. The second waveguide 1124 is used to transmit the second split light. Since the optical paths of the first waveguide 1122 and the second waveguide 1124 are different, there is an optical path difference between the first split light and the second split light, so that the first split light and the second split light transmitted through the first waveguide 1122 and the second waveguide 1124 have a corresponding phase difference.

[0113] In some embodiments, the optical path difference between the first waveguide 1122 and the second waveguide 1124 is designed such that the phases of the first split light and the second split light transmitted through the first waveguide 1122 and the second waveguide 1124 differ by 180 degrees.

[0114] In some embodiments, the wavelength locker 1106 adopts a Mach-Zehnder modulator structure with a dual-waveguide structure. The wavelength locker 1106 based on the Mach-Zehnder interference principle has a waveform in which the output intensity of the output light beam at the output end varies with the wavelength of the input light beam at the input end, which is related to the refractive index of the first waveguide 1122 and the second waveguide 1124 and their optical path lengths. The difference between the product of the refractive index and the waveguide length in the two waveguides determines the wavelength position of the input light velocity. Therefore, as long as the waveguide design satisfies the difference between the product of the two waveguides (the product of the refractive index and the waveguide length) at different temperatures, the waveform in which the output intensity of the output light beam at the output end varies with the wavelength of the input light beam at the input end at different temperatures can be ensured to remain unchanged, thereby achieving the temperature-insensitive characteristic of the wavelength of the input light beam.

[0115] In some embodiments, the first waveguide 1122 may be a silicon waveguide, and the second waveguide 1124 may be a silicon waveguide + a silicon nitride waveguide + a silicon waveguide. It is only necessary to adjust the lengths of the first waveguide 1122 and the second waveguide 1124 so that the difference between the product of the length and the refractive index of the first waveguide 1122 and the product of the length and the refractive index of the second waveguide 1124 remains unchanged, thereby achieving the insensitivity of wavelength to temperature.

[0116] Since the first end of the second waveguide 1124 is a silicon waveguide, the second end of the second waveguide 1124 is a silicon waveguide, and a silicon nitride waveguide is located between the first and second ends of the second waveguide 1124, in order to smoothly transmit a light beam of a preset wavelength between waveguides of two different materials, a second waveguide converter 1123 is provided on the second waveguide 1124, and the second waveguide converter 1123 is located between the silicon waveguide and the silicon nitride waveguide.

[0117] Since the second waveguide 1124 is provided with the second waveguide converter 1123 , in order to eliminate the influence of the second waveguide converter 1123 on the second waveguide 1124 , the first waveguide converter 1121 is correspondingly provided on the first waveguide 1122 .

[0118] The multimode interference coupler 1125 has two input optical ports and at least two output optical ports. The two input optical ports are respectively connected to the first waveguide 1122 and the second waveguide 1124 to inject the first light split and the second light split with phase difference into the multimode interference coupler 1125; the first light split and the second light split perform interference of different modes in the multimode interference coupler 1125, and output detection light of different phases from at least two output optical ports, and the difference between adjacent phases is 90 degrees.

[0119] In some embodiments, a multimode interference coupler is an optical device that can couple multiple light modes together to achieve the distribution and merging of optical signals. Its principle is based on the interference phenomenon of light and uses the phase difference when light waves propagate in optical fibers to achieve the coupling and separation of optical signals.

[0120] A multimode interference coupler is usually composed of two or more optical fibers. When a multimode interference coupler realizes the splitting of optical signals, at least one optical fiber is used as the input end and the other optical fiber is used as the output end. At the input end, the light wave will be divided into multiple modes, each mode has a different propagation path and phase difference. These light modes will interfere with each other inside the coupler to form multiple splits, which are then emitted through the output optical port.

[0121] The coupling efficiency of the multimode interference coupler depends on the phase difference of the light waves and the interference conditions. When the phase difference of the light waves is an even number, they will reinforce each other to form a strong composite light wave; when the phase difference is an odd number, they will cancel each other out to form a weak composite light wave. Therefore, the multimode interference coupler can control the phase difference of the light waves by adjusting the length and position of the optical fiber to achieve different coupling effects.

[0122] The optical detector group includes at least two optical detectors, which are used to convert the optical signal of the detection light into an electrical signal and transmit the electrical signal to the controller 303. The controller 303 can calculate the wavelength of the local oscillator light input to the wavelength locker based on the received electrical signal, thereby calculating the wavelength difference between the local oscillator light wavelength and the preset wavelength. The controller 303 feeds back a control signal to the laser component 900 based on the wavelength difference to adjust the wavelength of the local oscillator light output by the laser component 900, thereby achieving wavelength locking.

[0123] In some embodiments, the multimode interference coupler 1125 may have two input light ports and two output light ports, and the two input light ports are respectively connected to the first waveguide 1122 and the second waveguide 1124 to inject the first split light and the second split light with a phase difference into the multimode interference coupler 1125; the first split light and the second split light perform interference of different modes in the multimode interference coupler 1125, and the first detection light and the second detection light are output from the two output light ports, the first detection light and the second detection light have different phases, and the first detection light and the second detection light differ in phase by 90 degrees.

[0124] The optical detector group may include a first optical detector 1126 and a second optical detector 1127. The first optical detector 1126 converts the optical signal of the first detection light into an electrical signal, and the second optical detector 1127 converts the optical signal of the second detection light into an electrical signal. Then, the first optical detector 1126 and the second optical detector 1127 input the electrical signals into the controller 303. The controller 303 can calculate the input electrical signals to obtain the wavelength difference that needs to be adjusted. Then, the controller feeds back the wavelength difference information to the laser component 900, controls the laser component 900 to adjust the temperature or driving current, so as to stabilize the wavelength of the local oscillator light output by the laser component 900 at a preset wavelength to achieve wavelength locking.

[0125] In some embodiments, the multimode interference coupler 1125 may also have two input optical ports and four output optical ports, and the two input optical ports are respectively connected to the first waveguide 1122 and the second waveguide 1124 to inject the first split light and the second split light with a phase difference into the multimode interference coupler 1125; the first split light and the second split light perform interference of different modes in the multimode interference coupler 1125, and output the first detection light, the second detection light, the third detection light and the fourth detection light from the four output optical ports, the phase of the first detection light differs by 90 degrees from the phase of the second detection light, the phase of the second detection light differs by 90 degrees from the phase of the fourth detection light, and the phase of the fourth detection light differs by 90 degrees from the phase of the third detection light. For example, the phase of the first detection light is 0°, the phase of the second detection light is 90°, the phase of the fourth detection light is 180°, and the phase of the third detection light is 270°.

[0126] The optical detector group includes a first optical detector 1126, a second optical detector 1127, a third optical detector 1128 and a fourth optical detector 1129. The first optical detector 1126 converts the optical signal of the first detection light into an electrical signal, the second optical detector 1127 converts the optical signal of the second detection light into an electrical signal, the third optical detector 1128 converts the optical signal of the third detection light into an electrical signal, and the fourth optical detector 1129 converts the optical signal of the fourth detection light into an electrical signal. Then, the first optical detector 1126, the second optical detector 1127, the third optical detector 1128 and the fourth optical detector 1129 input the electrical signal into the controller 303. The controller 303 can calculate the input electrical signal to obtain the wavelength difference that needs to be adjusted. Then, the controller 303 feeds back the wavelength difference information to the laser component 900, controls the laser component 900 to adjust the temperature or the driving current, so as to stabilize the wavelength of the local oscillator light output by the laser component 900 at a preset wavelength to achieve wavelength locking.

[0127] Fig.14 FIG. 1 is a power curve diagram of a light detector in an optical module provided according to some embodiments of the present disclosure. Figure 6 and Fig.14 As shown, in order for the controller 303 to detect the wavelength of the local oscillator light incident on the coherent optical chip 1100, the controller 303 receives the electrical signal detected by the optical detector group, and the controller 303 stores the relationship curves between the optical power and the wavelength of the detection light of different phases, for example, Port 1: the relationship curve between the optical power and the wavelength of the detection light at 0°, Port 2: the relationship curve between the optical power and the wavelength of the detection light at 90°, Port 4: the relationship curve between the optical power and the wavelength of the detection light at 180°, and Port 3: the relationship curve between the optical power and the wavelength of the detection light at 270°.

[0128] The relationship curve between the optical power and wavelength of the detection light is a cosine curve, which has periodicity, and its period is related to the preset wavelength of the local oscillator light output by the laser assembly 900 and the optical path difference between the first waveguide 1122 and the second waveguide 1124. Different detection periods can be achieved according to different optical path difference designs. For example, the wavelength of the local oscillator light output by the laser assembly 900 is in the C band (1530nm to 1565nm). According to the C band and the optical path difference between the first waveguide 1122 and the second waveguide 1124, the detection period of the relationship curve is 1537 to 1541.5nm, that is, the preset wavelength of the local oscillator light output by the laser assembly 900 is 1537 to 1541.5nm.

[0129] When the wavelength locker 1106 outputs two detection lights, and the phases of the two detection lights differ by 90 degrees, the controller 303 can detect the wavelength according to the optical power ratio of the two detection lights that differ by 90 degrees. For example, the controller 303 calculates that the optical powers of the two detection lights are P1 and P2, respectively, and characterizes the wavelength change direction of the preset wavelength light beam according to P1 / P2.

[0130] For example, the wavelength of the preset wavelength light beam output by the laser assembly 900 is set to 1538nm. When the wavelength of the input light beam at the input end of the wavelength locker 1106 is 1538nm, P1 / P2 is equal to 1; when the wavelength of the input light beam at the input end of the wavelength locker 1106 is 1537.5nm, P1 / P2 is greater than 1, indicating that 1537.5nm deviates from the preset wavelength.

[0131] The wavelength shift direction of the specific wavelength light beam is known according to P1 / P2, and the controller 303 sends a control signal to the laser component 900 to adjust the temperature or driving current of the laser component 900 to stabilize the wavelength of the laser component 900 at the specific wavelength.

[0132] For example, the controller 303 calculates that P1 / P2 is greater than 1, indicating that the wavelength of the input light beam at the input end of the wavelength locker 1106 is less than the preset wavelength, and the wavelength of the local oscillator light output by the laser component 900 needs to be increased. At this time, the controller 303 can control the temperature of the TEC 907 in the laser component 900 to reduce the ambient temperature of the laser 902, thereby increasing the wavelength of the local oscillator light output by the laser component 900, until the P1 / P2 detected by the controller 303 is equal to 1, so that the wavelength of the local oscillator light output by the laser component 900 is stabilized at a specific wavelength.

[0133] When the controller 303 calculates that P1 / P2 is less than 1, it means that the wavelength of the input light beam at the input end of the wavelength locker 1106 is greater than the preset wavelength, and the wavelength of the local oscillator light output by the laser component 900 needs to be reduced. At this time, the controller 303 can control the temperature of the TEC 907 in the laser component 900 to increase the ambient temperature of the laser 902, thereby reducing the wavelength of the local oscillator light output by the laser component 900, until the controller 303 detects that P1 / P2 is equal to 1.

[0134] In some embodiments, the controller 303 can not only adjust the wavelength of the light beam output by the laser assembly 900 by controlling the temperature of the laser assembly 900, but also control the driving current transmitted to the laser assembly 900 to adjust the wavelength of the light beam output by the laser assembly 900. For example, when the driving current of the laser 902 increases and the wavelength of its output increases, when the controller 303 calculates that P1 / P2 is greater than 1, the controller 303 controls to increase the driving current transmitted to the laser 902 to increase the wavelength of the light beam output by the laser assembly 900 until the P1 / P2 detected by the controller 303 is equal to 1. When the controller calculates that P1 / P2 is less than 1, the controller 303 controls to reduce the driving current transmitted to the laser 902 to reduce the wavelength of the light beam output by the laser assembly 900 until the P1 / P2 detected by the controller 303 is equal to 1.

[0135] When the wavelength locker 1106 outputs four detection lights, and the phases of the four detection lights differ by 90 degrees, the controller 303 can detect the wavelength according to the optical power difference of the two detection lights that differ by 180 degrees. For example, the controller 303 calculates the optical powers of the four detection lights to be P1, P2, P3, and P4, respectively, and obtains the first optical power difference ΔP1 between P1 and P4, and the second optical power difference ΔP2 between P2 and P3. The controller 303 obtains the wavelength of the input light beam of the wavelength locker 1106 according to P1, P2, P3, P4, ΔP1, and ΔP2.

[0136] For example, the wavelength of the preset wavelength light beam output by the laser component 900 is set to 1538 nm, and the controller 303 obtains the wavelength of the input light beam of the wavelength locker 1106 as 1538.5 nm according to P1, P2, P3, P4, ΔP1, and ΔP2. According to the relationship curve between optical power and wavelength, it can be known that the wavelength of the input light beam of the wavelength locker 1106 differs from the preset wavelength by 0.5 nm, and the change relationship of port1 is that the optical power gradually increases to a maximum value, the change relationship of port2 is gradually increased, the change relationship of port3 is gradually decreased, and the change relationship of port4 is gradually decreased to a minimum value. According to the change relationship, the controller 303 feeds back a control signal to the laser component 900 to increase the temperature of the TEC 907, or reduce the driving current transmitted to the laser 902, thereby reducing the wavelength of the output light beam of the laser component 900, until the wavelength of the input light beam of the wavelength locker 1106 detected by the controller 303 reaches the preset wavelength.

[0137] In some embodiments, the controller 303 calculates the optical powers of the four detection lights to be P1, P2, P3, and P4, respectively, and obtains a first optical power ratio K1 between P1 and P4, and a second optical power ratio K2 between P2 and P3. The controller 303 obtains the wavelength of the input light beam of the wavelength locker 1106 based on P1, P2, P3, P4, K1, and K2.

[0138] For example, the wavelength of the preset wavelength light beam output by the laser component 900 is set to 1538 nm, and the controller 303 obtains the wavelength of the input light beam of the wavelength locker 1106 as 1537.5 nm according to P1, P2, P3, P4, K1, and K2. According to the relationship curve between optical power and wavelength, it can be known that the wavelength of the input light beam of the wavelength locker 1106 differs from the preset wavelength by 0.5 nm, and the change relationship of port1 is that the optical power gradually increases, the change relationship of port2 is that the optical power gradually increases from the minimum value, the change relationship of port3 is that the optical power gradually decreases, and the change relationship of port4 is that the optical power gradually decreases. According to the change relationship, the controller 303 feeds back a control signal to the laser component 900 to reduce the temperature of the TEC 907, or increase the driving current transmitted to the laser 902, thereby increasing the wavelength of the output light beam of the laser component 900, until the wavelength of the input light beam of the wavelength locker 1106 detected by the controller 303 reaches the preset wavelength.

[0139] In some embodiments, the two-path light splitting is separated into four-path detection light by the multimode interference coupler 1125 in the wavelength locker 1106, and the phases of the four-path detection light differ by 90 degrees. Compared with characterizing the wavelength change direction of the preset wavelength light beam according to the optical power ratio of the two-path detection light, the controller 303 determines the wavelength of the input light beam of the wavelength locker 1106 according to the optical power of the four-path detection light and the optical power difference of the two-path detection light with a phase difference of 180 degrees, and can accurately determine the wavelength of the input light beam of the wavelength locker 1106, and clarify the wavelength difference between the wavelength of the input light beam of the wavelength locker 1106 and the preset wavelength, thereby clarifying the approximate range of adjusting the wavelength of the output light beam of the laser component 900, such as how much to increase or decrease the temperature, or how much to increase or decrease the driving current, instead of repeated experiments.

[0140] The optical module provided by the embodiment of the present disclosure integrates a wavelength locker in the coherent optical chip, thereby realizing accurate monitoring, feedback and locking of the wavelength of the input light of the external light source, so that the external light source does not need to integrate a wavelength locking device, reducing the packaging complexity of the external light source. In addition, the coherent optical chip has both coherent transmission and reception functions and an integrated wavelength monitoring function, which meets the requirements of short-distance coherent application scenarios, where the line width and wavelength accuracy requirements of the external light source are reduced, but the requirements of being more sensitive to cost are met.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. An optical module, characterized in that: include: Circuit boards; A light source, electrically connected to the circuit board, and used to generate local oscillation light; A coherent optical chip is electrically connected to the circuit board, and the coherent optical chip includes: A first coupling port, optically connected to the light source, the first coupling port being used to input the local oscillator light; An optical splitter group, whose input end is connected to the first coupling port, and the optical splitter group is used to split the local oscillator light into multiple local oscillator light splits; a wavelength locker connected to an output end of the optical splitter group, the wavelength locker comprising a first waveguide, a second waveguide and a multimode interference coupler, the first waveguide and the second waveguide having different optical paths, and an input end of the multimode interference coupler being respectively connected to the first waveguide and the second waveguide; the wavelength locker is used to split one path of the local oscillator into two beams of light, the two beams of light are transmitted via the first waveguide and the second waveguide, and the multimode interference coupler outputs at least two paths of detection light with different phases; A controller is disposed on the circuit board, the controller is electrically connected to the coherent optical chip and the light source respectively, the controller is used to obtain the optical power of the at least two detection lights, determine the wavelength of the local oscillation light according to the optical power and the relationship curve between the optical power and the wavelength stored in the controller, and adjust the wavelength of the local oscillation light output by the light source according to the wavelength difference between the wavelength of the local oscillation light and a preset wavelength to achieve wavelength locking.

2. The optical module according to claim 1, characterized in that: The wavelength locker also includes: A first optical splitter, whose input end is connected to an output end of the optical splitter group, the first optical splitter is used to split the local oscillator light into a first light split and a second light split, the first waveguide is used to transmit the first light split, and the second waveguide is used to transmit the second light split; The multimode interference coupler has an output end including at least two output light ports, so that the first light splitting and the second light splitting interfere with each other to output at least two detection lights with different phases; The photodetector group includes at least two photodetectors, and the photodetectors are used to convert the optical signal of the detection light into an electrical signal and transmit the electrical signal to the controller.

3. The optical module according to claim 2, characterized in that: The multimode interference coupler comprises four output light ports, the first split light and the second split light output the first detection light, the second detection light, the third detection light and the fourth detection light through the multimode interference coupler, the first detection light and the second detection light have a phase difference of 90 degrees, the second detection light and the fourth detection light have a phase difference of 90 degrees, and the fourth detection light and the third detection light have a phase difference of 90 degrees; The optical detector group includes four optical detectors, and the four optical detectors convert optical signals of the first detection light, the second detection light, the third detection light, and the fourth detection light into electrical signals respectively.

4. The optical module according to claim 3, characterized in that: The controller is configured to receive the electrical signal sent by the detector group, calculate the optical power of the first detection light, the second detection light, the third detection light and the fourth detection light, obtain the first optical power difference between the first detection light and the fourth detection light and the second optical power difference between the second detection light and the third detection light, and determine the wavelength of the local oscillator light according to the optical power, the first optical power difference, the second optical power difference and the relationship curve between the optical power and the wavelength.

5. The optical module according to claim 3, characterized in that: The controller is configured to receive the electrical signal sent by the detector group, calculate the optical power of the first detection light, the second detection light, the third detection light and the fourth detection light, obtain a first optical power ratio of the first detection light to the fourth detection light and a second optical power ratio of the second detection light to the third detection light, and determine the wavelength of the local oscillator light according to the optical power, the first optical power ratio, the second optical power ratio and a relationship curve between the optical power and the wavelength.

6. The optical module according to claim 1, characterized in that: The controller is further configured to adjust the ambient temperature of the light source according to the wavelength difference between the local oscillation light wavelength and the preset wavelength, so as to adjust the wavelength of the local oscillation light output by the light source.

7. The optical module according to claim 1, characterized in that: The controller is further configured to adjust the driving current transmitted to the light source according to the wavelength difference between the wavelength of the local oscillation light and the preset wavelength, so as to adjust the wavelength of the local oscillation light output by the light source.

8. The optical module according to claim 1, characterized in that: The optical splitter group comprises: a directional coupler, wherein an input end of the directional coupler is connected to the first coupling port, and a first output end of the directional coupler is connected to the wavelength locker; A second optical splitter, whose input end is connected to the second output end of the directional coupler, and whose first output end is connected to the polarization balanced detector group; The input end of the third optical splitter is connected to the second output end of the second optical splitter, and the output ends of the third optical splitter are respectively connected to the bi-coherent modulators.

9. The optical module according to claim 1, characterized in that: The relationship curve between the optical power and the wavelength is a cosine curve, and the detection period of the relationship curve is determined according to the preset wavelength of the local oscillation light and the optical path difference between the first waveguide and the second waveguide.

10. An optical module, characterized in that: include: Circuit boards; A light source, electrically connected to the circuit board, and used to generate local oscillation light; A coherent optical chip is electrically connected to the circuit board, and the coherent optical chip includes: A first coupling port, optically connected to the light source, the first coupling port being used to input the local oscillator light; An optical splitter group, whose input end is connected to the first coupling port, and the optical splitter group is used to split the local oscillator light into multiple local oscillator light splits; A wavelength locker is connected to an output end of the optical splitter group, and the wavelength locker includes: A first optical splitter, whose input end is connected to an output end of the optical splitter group, and the first optical splitter is used to split the local oscillator light into a first split light and a second split light; A first waveguide connected to a first output end of the first optical splitter, the first waveguide being used to transmit the first split light; a second waveguide connected to a second output end of the first optical splitter, the second waveguide being used to transmit the second split light; A multimode interference coupler, wherein the output end of the multimode interference coupler comprises four output light ports, so that the first light splitting and the second light splitting interfere with each other to output four detection lights of different phases, wherein the phases differ by 90 degrees respectively; A photodetector group, comprising four photodetectors, wherein the photodetectors are used to convert the optical signal of the detection light into an electrical signal; A controller is arranged on the circuit board, the controller is electrically connected to the coherent optical chip and the light source respectively, the controller is used to obtain the optical power of the four detection lights, determine the wavelength of the local oscillation light according to the four optical powers and the relationship curve between the optical power and the wavelength stored in the controller, and adjust the wavelength of the local oscillation light output by the light source according to the wavelength difference between the wavelength of the local oscillation light and a preset wavelength to achieve wavelength locking.

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