Optical module

Abstract

The present disclosure provides an optical module, comprising a light source, a coherent light chip and a controller, the coherent light chip comprising a first coupling port, a beam splitter set connected with the first coupling port, and a wavelength locker connected with an output end of the beam splitter set, the first coupling port being used for receiving local light generated by the light source, the beam splitter set being used for splitting the local light into multiple local light beams; the wavelength locker comprising two waveguides with different optical paths and a multimode interference coupler, the wavelength locker splitting one local light beam into two light beams, the two light beams being transmitted through the two waveguides and outputting at least two probe light beams with different phases by the multimode interference coupler; the controller acquiring optical powers of the at least two probe light beams, determining a wavelength of the local light according to the optical powers and a relationship curve of optical power and wavelength in the controller, and adjusting the wavelength of the local light output by the light source according to a wavelength difference between the wavelength of the local light and a preset wavelength. The present disclosure integrates the wavelength locker in the coherent light chip, thereby reducing the packaging complexity of the light source.

Description

TECHNICAL FIELD

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

[0002] In cloud computing, mobile Internet, video and other new business and application modes, optical communication technology will be used. In optical communication, an optical module is a device for converting optical signals and is one of the key devices in optical communication equipment.

[0003] For a coherent optical module, generally includes a light source and a coherent light chip. The light source is connected with the coherent light chip. The light emitted by the light source is incident to the coherent light chip. The incident light is split in the coherent light chip. One of the split beams enters a coherent modulator in the coherent light chip to realize electrical-optical signal conversion. The converted optical signal is emitted from an optical transmitting interface. The other split beam is a local oscillator light. The coherent light chip inputs an optical signal via an optical receiving interface. The local oscillator light and the input optical signal are coherently demodulated to complete optical-electrical signal conversion.

[0004] At present, the light source of the coherent optical module is a narrow linewidth wavelength tunable light source. A wavelength locking device is integrated in the light source. The wavelength locking device is used for monitoring the wavelength of the light emitted by the laser and performing real-time wavelength locking. However, the packaging process of the light source integrated with the wavelength locking device is complex and the cost is high. SUMMARY

[0005] Embodiments of the present disclosure provide 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] a circuit board;

[0008] a light source, electrically connected with the circuit board, the light source being configured to generate a local oscillator light;

[0009] a coherent light chip, electrically connected with the circuit board, the coherent light chip comprising:

[0010] a first coupling port, optically connected with the light source, the first coupling port being configured to input the local oscillator light;

[0011] a beam splitter group, an input end of the beam splitter group being connected with the first coupling port, the beam splitter group being configured to split the local oscillator light into multiple local oscillator beams;

[0012] a wavelength locker connected to an output end of the optical splitter set, 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 the multimode interference coupler having input ends connected to the first waveguide and the second waveguide respectively, the wavelength locker being configured to split one of the local oscillator splittings into two beams of light, the two beams of light being transmitted through the first waveguide and the second waveguide and output from the multimode interference coupler as at least two beams of probe light having different phases;

[0013] a controller disposed on the circuit board, the controller being electrically connected to the coherent light chip and the light source respectively, the controller being configured to acquire optical powers of the at least two beams of probe light, determine a wavelength of the local oscillator light according to the optical powers and a relationship curve between optical powers and wavelengths stored in the controller, and adjust the wavelength of the local oscillator light output by the light source according to a wavelength difference between the wavelength of the local oscillator light and a preset wavelength, so as to achieve wavelength locking.

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

[0015] a circuit board;

[0016] a light source electrically connected to the circuit board, the light source being configured to generate local oscillator light;

[0017] a coherent light chip electrically connected to the circuit board, the coherent light chip comprising:

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

[0019] an optical splitter set having an input end connected to the first coupling port, the optical splitter set being configured to split the local oscillator light into a plurality of local oscillator splittings;

[0020] a wavelength locker connected to an output end of the optical splitter set, the wavelength locker comprising:

[0021] a first optical splitter having an input end connected to an output end of the optical splitter set, the first optical splitter being configured to split one of the local oscillator splittings into a first splitting and a second splitting;

[0022] a first waveguide connected to a first output end of the first optical splitter, the first waveguide being configured to transmit the first splitting;

[0023] a second waveguide connected to a second output end of the first optical splitter, the second waveguide being configured to transmit the second splitting;

[0024] The multi-mode interference coupler has four output light ports at the output end, so that the first split light and the second split light interfere to output four-way detection light with different phases, and the phases are 90 degrees apart respectively.

[0025] The light detector group includes four light detectors, and the light detectors are used to convert the optical signals of the detection light into electrical signals.

[0026] The controller is arranged on the circuit board, and the controller is electrically connected with the coherent light chip and the light source respectively. The controller is used to acquire the optical powers of the four-way detection light, determine the wavelength of the local oscillation light according to the four optical powers and a wavelength-power relationship curve 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, so as to realize wavelength locking.

[0027] As can be seen from the above embodiments, the optical module provided by the embodiments of the present disclosure includes a circuit board, a light source, a coherent light chip and a controller. The light source is electrically connected with the circuit board, so that the light source generates local oscillation light. The coherent light chip is electrically connected with the circuit board. The coherent light chip includes a first coupling port, a beam splitter group and a wavelength locker. The first coupling port is connected with the light source, so that the local oscillation light generated by the light source is transmitted to the coherent light chip through the first coupling port. The input end of the beam splitter group is connected with the first coupling port. The beam splitter group is used to split the local oscillation light into multiple local oscillation split lights, so as to realize coherent emission and reception of the coherent light chip through the multiple local oscillation split lights. The wavelength locker is connected with an output end of the beam splitter group. The wavelength locker includes a first waveguide, a second waveguide and a multi-mode interference coupler. The optical path of the first waveguide is different from that of the second waveguide. The input end of the multi-mode interference coupler is connected with the first waveguide and the second waveguide respectively. The wavelength locker is used to split one local oscillation split light into two beams of light. The two beams of light are transmitted through the first waveguide and the second waveguide, and at least two-way detection light with different phases is output by the multi-mode interference coupler, so as to obtain multiple-way detection light with different phases through the wavelength locker. The controller is arranged on the circuit board. The controller is electrically connected with the coherent light chip and the light source respectively. The controller acquires the optical powers of the multiple-way detection light with different phases, determines the wavelength of the local oscillation light according to the multiple optical powers and a wavelength-power relationship curve stored in the controller, calculates the wavelength difference between the wavelength of the local oscillation light and a preset wavelength, and feeds back a control signal to the light source according to the wavelength difference, so as to adjust the wavelength of the local oscillation light output by the light source. The wavelength of the adjusted local oscillation light reaches the preset wavelength, so as to realize wavelength locking.

[0028] The present disclosure integrates the wavelength locker in the coherent light chip, which can realize accurate monitoring, feedback and locking of the wavelength of the input light of the external light source. Therefore, the external light source does not need to integrate the wavelength locking device, which can reduce the packaging complexity of the external light source. Moreover, the coherent light chip has both coherent emission and reception functions and integrated wavelength monitoring function, which can meet the short-distance coherent application. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are only drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual size of the product, the actual flow of the method, the actual timing of the signal, etc. involved in the embodiments of this disclosure.

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

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

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

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

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

[0035] Figure 6 This is a schematic diagram illustrating the working principle of an optical module according to some embodiments of the present disclosure;

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

[0037] Figure 8 This is a structural framework of a coherent optical chip in an optical module according to some embodiments of the present disclosure. Figure 1 ;

[0038] Figure 9 This is a structural framework of a coherent optical chip in an optical module according to some embodiments of the present disclosure. Figure 2 ;

[0039] Figure 10 This is a structural framework of a coherent optical chip in an optical module according to some embodiments of the present disclosure. Figure 3 ;

[0040] Figure 11 This is a structural framework of a coherent optical chip in an optical module according to some embodiments of the present disclosure. Figure 4 ;

[0041] Figure 12 A structure diagram of a wavelength locker in an optical module according to some embodiments of the present disclosure Figure 5 ;

[0042] Figure 13 A structure diagram of a wavelength locker in an optical module according to some embodiments of the present disclosure

[0043] Figure 14 A power curve diagram of an optical detector in an optical module according to some embodiments of the present disclosure DETAILED DESCRIPTION

[0044] The technical solutions in some embodiments of the present disclosure will be described clearly and in detail below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present disclosure, but not all the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by those skilled in the art 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, information needs to be loaded onto light to realize information transmission by using the propagation of light. Here, the light loaded with information is an optical signal. The optical signal can reduce the loss of optical power when transmitted in the information transmission device, so as to realize high-speed, long-distance and low-cost information transmission. The signal that can be recognized and processed by the information processing device is an electrical signal. The information processing device usually includes an optical network unit (ONU), a gateway, a router, a switch, a mobile phone, a computer, a server, a tablet computer, a television, etc., and the information transmission device usually includes an optical fiber and an optical waveguide, etc.

[0046] The optical module can realize mutual conversion between optical signals and electrical signals between the information processing device and the information transmission device. For example, at least one of the optical signal input end or the optical signal output end of the optical module is connected with 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 with an optical network terminal; a first optical signal from the optical fiber is transmitted to the optical module, the optical module converts the first optical signal into a first electrical signal, and transmits the first electrical signal to the optical network terminal; a second electrical signal from the optical network terminal is transmitted to the optical module, the optical module converts the second electrical signal into a second optical signal, and transmits the second optical signal to the optical fiber. Since information transmission can be performed between multiple information processing devices through electrical signals, at least one of the multiple information processing devices needs to be directly connected with the optical module, without the need for all the information processing devices to be directly connected with the optical module. Here, the information processing device directly connected with the optical module is referred to as a host computer of the optical module. In addition, the optical signal input end or the optical signal output end of the optical module can be referred to as an optical port, and the electrical signal input end or the electrical signal output end of the optical module can be referred to as an electrical port.

[0047] Figure 1 A partial structure diagram of an optical communication system according to some embodiments of the present disclosure is provided. As shown in Figure 1 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 to the direction of the remote information processing device 1000, and the other end of the optical fiber 101 is connected with 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 totally reflected direction can almost maintain the original optical power. The optical signal is totally reflected multiple times 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 and low-power-loss information transmission.

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

[0050] The host computer 100 includes a housing substantially in the shape of a rectangular cuboid, and an optical module interface 102 disposed on the housing. The optical module interface 102 is configured to access the optical module 200, so that the host computer 100 and the optical module 200 establish one-way or two-way electrical signal connection.

[0051] The host computer 100 further comprises an external electrical interface which can access an electrical signal network. For example, the external electrical interface comprises a Universal Serial Bus (USB) interface or a network cable interface 104 configured to access a network cable 103 to establish a unidirectional or bidirectional electrical signal connection between the host computer 100 and 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 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, a third electrical signal emitted 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. The second optical signal is transmitted in the optical fiber 101 to the remote information processing device 1000. For example, the first optical signal from the remote information processing device 1000 is transmitted through the optical fiber 101, the first optical signal from the optical fiber 101 is transmitted to the optical module 200, the optical module 200 converts the first optical signal into a first electrical signal, the optical module 200 transmits the first electrical signal to the host computer 100, the host computer 100 generates a fourth electrical signal according to the first electrical signal, and the fourth electrical signal is transmitted to the local information processing device 2000. It should be noted that the optical module is a tool for converting optical signals and electrical signals, and the information does not change in the conversion process of the optical signals and the electrical signals, and the encoding and decoding mode of the information can change.

[0052] The host computer 100 comprises an optical network terminal, an optical line terminal (OLT), an optical network terminal (ONT), or a data center server, etc.

[0053] Figure 2 A partial structural diagram of a host computer according to some embodiments of the present disclosure is provided. 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. As Figure 2 shown, the host computer 100 further comprises a PCB circuit board 105 arranged in the housing, a cage 106 arranged on the surface of the PCB circuit board 105, a heat sink 107 arranged on the cage 106, and an electrical connector arranged 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 light module 200 is inserted into the cage 106 of the host computer 100, and the light module 200 is fixed by the cage 106. The heat generated by the light module 200 is conducted to the cage 106, and then diffused through the heat sink 107. After the light module 200 is inserted into the cage 106, the electrical port of the light module 200 is connected with the electrical connector inside the cage 106, so that the light module 200 and the host computer 100 establish a bidirectional electrical signal connection. In addition, the optical port of the light module 200 is connected with the optical fiber 101, so that the light module 200 and the optical fiber 101 establish a bidirectional optical signal connection.

[0055] Figure 3 FIG. 1 is a structural diagram of a light module according to some embodiments of the present disclosure, Figure 4 FIG. 2 is an exploded view of a light module according to some embodiments of the present disclosure. As shown in Figure 3 and Figure 4 The light module 200 includes a shell, a circuit board 300 arranged in the shell, a light source, a coherent light 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 shell includes an upper shell 201 and a lower shell 202. The upper shell 201 is covered on the lower shell 202 to form the above-mentioned shell with two openings 204 and 205. The outer contour of the shell generally presents a square body.

[0057] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 arranged perpendicularly to the bottom plate 2021 on both sides of the bottom plate 2021. The upper shell 201 includes a cover plate 2011, and the cover plate 2011 is covered on 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 arranged perpendicularly to the bottom plate 2021 on both sides of the bottom plate 2021. The upper shell 201 includes a cover plate 2011 and two upper side plates arranged perpendicularly to the cover plate 2011 on both sides of the cover plate 2011. The two upper side plates and the two lower side plates 2022 are combined to achieve that the upper shell 201 is covered on the lower shell 202.

[0059] The direction of the line connecting the two openings 204 and 205 can be consistent with the length direction of the light module 200, or can be inconsistent with the length direction of the light module 200. For example, the opening 204 is located at the end (right end) of the light module 200, and the opening 205 is also located at the end of the light module 200. Figure 3 Figure 3 ​Or, 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 fingers of the circuit board 300 extend from the electrical port and are inserted into the electrical connector of the host computer 100; the opening 205 is an optical port configured to access the external optical fiber 101 so that the optical fiber 101 is connected to the coherent light chip 1100 in the optical module 200.

[0060] The assembly of the upper shell 201 and the lower shell 202 facilitates the installation of the circuit board 300, the light source, the coherent light chip 1100, the transmitting fiber adapter 700, and the receiving fiber adapter 800 into the shells, and the shells can protect the above-mentioned devices. In addition, when assembling the circuit board 300, the light source, the coherent light chip 1100, the transmitting fiber adapter 700, and the receiving fiber adapter 800, the assembly of the upper shell 201 and the lower shell 202 facilitates the deployment of the positioning components, heat dissipation components, and electromagnetic shielding components of these devices, which is conducive to the automated production.

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

[0062] In some embodiments, the optical module 200 further includes an unlocking component 600 located outside the shell of the optical module 200. The unlocking component 600 is configured to achieve the 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 outside the two lower side plates 2022 of the lower shell 202 and includes a clamping component matched with the cage 106 of the host computer 100. When the optical module 200 is inserted into the cage 106, the clamping component of the unlocking component 600 fixes the optical module 200 in the cage 106; when the unlocking component 600 is pulled, the clamping component of the unlocking component 600 moves, thereby changing the connection relationship between the clamping component and the host computer, to release the fixation between the optical module 200 and the host computer, so that the optical module 200 can be pulled out of the cage 106.

[0064] Circuit board 300 includes circuit traces, electronic components, and chips. The circuit traces connect the electronic components and chips according to the circuit design to achieve functions such as power supply, electrical signal transmission, and grounding. Electronic components may include, for example, capacitors, resistors, transistors, and metal-oxide-semiconductor field-effect transistors (MOSFETs). Chips may include, for example, microcontroller units (MCUs), laser driver chips, transimpedance amplifiers (TIAs), limiting amplifiers (LAs), clock and data recovery chips (CDRs), power management chips, and digital signal processing (DSP) chips.

[0065] Circuit board 300 is generally a rigid circuit board. Due to its relatively hard material, the rigid circuit board can also perform a load-bearing function. For example, the rigid circuit board can stably support the aforementioned 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 gold fingers formed on its end surfaces, each gold finger consisting of a plurality of independent pins. The circuit board 300 is inserted into a cage 106 and is electrically connected to an electrical connector within the cage 106 by the gold fingers. The gold fingers may be located only on one side of the surface of the circuit board 300 (e.g., ...). Figure 4 The upper surface shown can also be positioned on the upper and lower surfaces of the circuit board 300 to provide a greater number of pins, thus adapting to applications with high pin count requirements. The gold fingers are 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, and data signal transmission. Of course, flexible circuit boards are also used in some optical modules. Flexible circuit boards are generally used in conjunction with rigid circuit boards as a supplement to rigid circuit boards.

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

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

[0069] Figure 5 This is a partial structural diagram of an optical module provided according to some embodiments of the present disclosure. Figure 6 This is a schematic diagram illustrating the working principle of an optical module according to some embodiments of the present disclosure. Figure 5 and Figure 6 As shown, the coherent optical chip 1100 is a coherent silicon photonic integrated chip. Since silicon material in silicon photonic chips is not an ideal light-emitting material for laser chips, light-emitting units cannot be integrated during the fabrication process of silicon photonic chips. Therefore, silicon photonic chips require light from an external light source. For example, a laser assembly 900 is used as an external light source to provide light to the silicon photonic chip.

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

[0071] The circuit board 300 is equipped with a digital signal processing chip 302, a driver chip 304, and an amplifier chip 305. 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 modulation 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 transmitted optical signal. The digital signal processing chip 302 receives the received electrical signal fed back by the coherent optical chip 1100 through the amplifier chip 305, and performs demodulation processing on 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 linewidth and high power laser emitted by the laser component 900 is coupled to the coherent optical chip 1100 through the local oscillator optical interface. The laser is split inside the coherent optical chip 1100, and one of the beams is used as the emitted light to enter the coherent modulator inside the coherent optical chip 1100. Under the high-speed electrical signal drive of the digital signal processing chip 302, the electro-optic signal is converted. The converted high-speed optical signal is output from the optical emission interface. The optical signal is transmitted through the emission optical fiber to the emission optical fiber adapter 700 and then emitted through the emission optical fiber adapter 700 to realize the emission of coherent light.

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

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

[0075] To solve the above problems, the embodiments of the present disclosure provide an optical module, which integrates a wavelength locking device inside the coherent light chip 1100. Through the wavelength locking device, the wavelength of the light emitted by the external laser assembly 900 can be monitored in real time, and a feedback signal can be generated to the external laser assembly for preset wavelength adjustment and locking, thereby simplifying the packaging complexity and cost of the external laser assembly 900 and meeting the use requirements of short-distance coherent optical modules.

[0076] Figure 7 A cross-sectional view of a light source in an optical module according to some embodiments of the present disclosure is shown in FIG. 1. As shown in FIG. 1, the laser assembly 900 includes a housing 901 and a cover plate, the cover plate being covered in the housing 901, so that the housing 901 and the cover plate form a cavity; the housing 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 oppositely arranged, and the third side plate is the right side plate of the housing 901, an opening is formed on the left side of the housing 901, and an opening is formed on the top surface of the housing 901. Figure 7

[0077] The left side of the housing 901 is provided with a boss 909, the boss 909 is installed on the bottom plate of the housing 901, the boss 909 is oppositely arranged with the third side plate, the surface of the boss 909 is provided with a conversion circuit board 910, one end of the conversion circuit board 910 is located in the receiving cavity of the housing 901, the other end of the conversion circuit board 910 is located outside the receiving cavity, and the end of the conversion circuit board 910 located outside the receiving cavity is electrically connected with the circuit board 300 through wire bonding 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 conversion 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 connecting piece 920 is arranged in the through hole 911, the optical fiber connecting piece 920 is coupled with the light source optical fiber, and the light source optical fiber is a polarization maintaining optical fiber, so as to realize the coupling connection between the laser assembly 900 and the light source optical fiber.

[0079] ​In some embodiments, the TEC 907 and the carrier plate 908 are arranged in the accommodating cavity of the shell 901, the surface of the TEC 907 is provided with the laser 902 and the collimating lens 903, the laser 902 receives the driving electrical signal transmitted by the circuit board 300 through the adapter circuit board 910, so that the laser 902 generates laser light without carrying data; the collimating lens 903 is located in the light emitting direction of the laser 902, and the collimating lens 903 converts the laser light generated by the laser 902 into parallel light.

[0080] Since in coherent communication, the wavelength difference (or frequency difference) between the received optical signal and the local oscillator signal needs to be less than a certain specific value to generate interference and ensure that the digital signal processing chip 302 can process the response signal, the wavelength of the laser 902 needs to be kept in a very stable state, and therefore the TEC 907 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, the surface of the carrier plate 908 is provided with the converging lens 905, and the parallel light emitted by the collimating lens 903 is converged into the light source fiber in the fiber connector 920 through the converging lens 905, so as to couple the laser light generated by the laser 902 to the light source fiber.

[0082] Due to the difference in transmission medium, the converging light emitted by the converging lens 905 is easy to reflect at the fiber end face of the light source fiber. In order to prevent the reflected light from returning to the laser 902 along the original path, the surface of the carrier plate 908 is further provided with the optical isolator 904, 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 is incident into the converging lens 905, the parallel light is converged into the light source fiber through the converging lens 905, and the reflected light of the light at the fiber end face is isolated by the optical isolator 904 and cannot return to the laser 902 through the optical isolator 904, thereby ensuring the light emitting 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 axis 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, thereby facilitating the coupling of the laser light generated by the laser 902 to the light source fiber.

[0084] In some embodiments, when performing optical coupling of the laser assembly 900, the subsequent installation direction of the laser assembly 900 on the circuit board 300 needs to be considered, and the placement position of the light source fiber is adjusted, so as to avoid twisting of the light source fiber when the laser assembly 900 is installed on the module circuit board 300.

[0085] Figure 8A structure frame of a coherent light chip in an optical module according to some embodiments of the present disclosure Figure 1 . As Figure 6 shown in Figure 8 , the optical module provided by the embodiments of the present disclosure includes a circuit board 300, a laser assembly 900 and a coherent light chip 1100, the laser assembly 900 and the coherent light chip 1100 are mounted on the circuit board 300, and a controller 303 is further arranged on the circuit board 300, the laser assembly 900 is connected with the coherent light chip 302 through a polarization maintaining optical fiber to input a local oscillator light to the coherent light chip 302; the coherent light chip 302 is electrically connected with the controller 303 to feed back an electrical signal to the controller 303; the controller 303 is in control connection with the laser assembly 900 to send a control signal to the laser assembly 900 according to the feedback electrical signal received by the controller 303, so as to control the wavelength of the laser generated by the laser assembly 900.

[0086] In order to receive the local oscillator light generated by the laser assembly 900, the coherent light 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 process encapsulated with a three-channel optical fiber array to realize the interconnection between the coherent light chip 1100 and an external optical signal.

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

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

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

[0090] The coherent light chip 1100 is integrated with a wavelength locker 1106, and the wavelength locker 1106 is connected with an output end of the beam splitter set, that is, the third part of light enters the wavelength locker 1106. The wavelength locker 1106 can detect the wavelength of the entering light, and transmits the detected electrical signal to the controller 303. The controller 303 calculates the wavelength difference between the detected wavelength and the preset wavelength according to the detected electrical signal, and feeds back the control signal to the laser assembly 900 according to the wavelength difference, so as to adjust the wavelength of the laser generated by the laser assembly 900, thereby stabilizing the wavelength of the laser generated by the laser assembly 900 at the preset wavelength, so as to realize the wavelength locking.

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

[0092] The input end of the second optical splitter 1105 is connected with 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 with the second output end of the directional coupler 1104 to input the second local oscillator light to the wavelength locker 1106. The wavelength locker 1106 detects the second local oscillator light. The controller 303 receives an electrical signal detected by the wavelength locker 1106, and determines the wavelength of the second local oscillator light according to the electrical signal. Then, the wavelength difference between the wavelength of the second local oscillator light and the preset wavelength is calculated. The controller 303 controls the wavelength of the laser assembly 900 according to the wavelength difference, so that the wavelength of the laser assembly 900 is stabilized at the preset wavelength.

[0093] The second optical splitter 1105 divides the first local oscillator light into a first local oscillator sub-light and a second local oscillator sub-light. The first local oscillator sub-light enters the fourth optical splitter 1115 as a local oscillator light. The fourth optical splitter 1115 divides the first local oscillator sub-light into two lights, which enter the first frequency mixer 1112 and the second frequency mixer 1113, respectively. The received light from the second coupling port 1102 is divided into two lights by the receiving polarization rotation beam splitter, which enter the first frequency mixer 1112 and the second frequency mixer 1113, respectively. The local oscillator light and the received light are mixed by the frequency mixers, so that the demodulation processing of the optical signal is realized. Then, the electrical signal after demodulation 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 processing, so that the coherent light is received.

[0094] The second local oscillator sub-light enters the third optical splitter 1107. The third optical splitter 1107 divides the second local oscillator sub-light into two lights, which enter the first quadrature coherent modulator 1108 and the second quadrature coherent modulator 1109, respectively. After the electrical-optical signal loading, the two lights obtain two quadrature signal lights. The two quadrature signal lights obtain one signal light through the transmitting polarization rotation beam splitter 1110. The one signal light is emitted from the third coupling port 1103, so that the coherent light is emitted.

[0095] In some embodiments, the wavelength locker 1106 receives one local oscillator light from the directional coupler 1104 in the optical splitter group. The wavelength locker 1106 outputs at least two detection lights from the one local oscillator light. The controller 303 determines the wavelength of the local oscillator light 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 with only one output end of the directional coupler 1104. As long as the wavelength locker 1106 can receive one local oscillator light, it is acceptable.

[0096] Figure 9 This is a structural framework of a coherent optical chip in an optical module according to some embodiments of the present disclosure. Figure 2 .like Figure 9 As shown, the beam splitter group includes a second beam splitter 1105, a directional coupler 1104, and a third beam splitter 1107. The input terminal of the second beam splitter 1105 is connected to the first coupling port 1101 to receive the local oscillator light output from the laser assembly 900. The second beam splitter 1105 splits the local oscillator light into a first local oscillator beam and a second local oscillator beam. The first local oscillator beam, as the local oscillator light, enters the fourth beam splitter 1115. The fourth beam splitter 1115 splits the first local oscillator beam into two beams, which enter the first mixer 1112 and the second mixer 1113, respectively. 13; The received light entering from the second coupling port 1102 is split into two beams by the receiving polarization rotating beam splitter. The two beams enter the first mixer 1112 and the second mixer 1113 respectively. The local oscillator light and the received light are mixed by the mixer to achieve demodulation 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 processing, thus realizing the reception of coherent light.

[0097] The input terminal of the directional coupler 1104 is connected to the second output terminal of the second beam splitter 1105. The second local oscillator beam enters the directional coupler 1104, which splits the second local oscillator beam into the first local oscillator beam and the second local oscillator beam. The wavelength locker 1106 is connected to the first output terminal of the directional coupler 1104, so that the first local oscillator beam enters the wavelength locker 1106. The wavelength locker 1106 detects the first local oscillator beam, 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 of the third beam splitter 1107 is connected to the second output of the directional coupler 1104. The third beam splitter 1107 splits the second local oscillator beam into two beams. The two beams enter the first orthogonal coherent modulator 1108 and the second orthogonal coherent modulator 1109, respectively. After being loaded with electro-optic signals, the two beams are converted into two orthogonal signal beams. The two orthogonal signal beams are converted into one signal beam by the transmitting polarization rotating beam splitter 1110. The signal beam is emitted from the third coupling port 1103, thus realizing the emission of coherent light.

[0099] Figure 10 This is a structural framework of a coherent optical chip in an optical module according to some embodiments of the present disclosure. Figure 3 .like Figure 10As shown, the optical splitter set 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 first local oscillator light and second local oscillator light. 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 first local oscillator sub-light and second local oscillator sub-light. The first local oscillator sub-light enters the fourth optical splitter 1115 as local oscillator light. The fourth optical splitter 1115 splits the first local oscillator light into two beams of light, which enter the first frequency mixer 1112 and the second frequency mixer 1113, respectively. The received light that enters from the second coupling port 1102 is split into two beams of light by the receiving polarization rotation beam splitter, which enter the first frequency mixer 1112 and the second frequency mixer 1113, respectively. The local oscillator light and the received light are mixed by the frequency mixers, thereby achieving demodulation processing of the optical signal. Then, the demodulated electrical signal is input to the amplifier chip 305 through the first high-speed detector set 1116 and the second high-speed detector set 1114, respectively. After being amplified, the electrical signal is input to the digital signal processing chip 302 for processing of the electrical signal, thereby achieving reception of the 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 sub-light enters the wavelength locker 1106. The wavelength locker 1106 detects the second local oscillator sub-light, 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 optical splitter 1107 is connected to the second output end of the second optical splitter 1105, so that the second local oscillator light enters the third optical splitter 1107. The third optical splitter 1107 splits the second local oscillator light into two beams of light, which enter the first quadrature coherent modulator 1108 and the second quadrature coherent modulator 1109, respectively. After being loaded with electrical-optical signals, the two beams of light obtain two beams of quadrature signal light. The two beams of quadrature signal light obtain one beam of signal light through the transmitting polarization rotation beam splitter 1110. The one beam of signal light is emitted from the third coupling port 1103, thereby achieving emission of the coherent light.

[0102] Figure 11 A structure of a coherent light chip in an optical module according to some embodiments of the present disclosure Figure 4 As shown in FIG. 1, the coherent light chip includes a laser assembly 900, a wavelength locker 1106, a directional coupler 1104, a second optical splitter 1105, a third optical splitter 1107, a first quadrature coherent modulator 1108, a second quadrature coherent modulator 1109, a transmitting polarization rotation beam splitter 1110, a first frequency mixer 1112, a second frequency mixer 1113, a first high-speed detector set 1116, a second high-speed detector set 1114, a fourth optical splitter 1115, and a controller 303. Figure 11As shown, the optical splitter set 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 with the first coupling port 1101 to receive the local oscillator light output by the laser assembly 900. The second optical splitter 1105 divides the local oscillator light into first local oscillator light and second local oscillator light. The first local oscillator light enters a fourth optical splitter 1115 as local oscillator light. The fourth optical splitter 1115 divides the first local oscillator light into two beams of light, which enter a first frequency mixer 1112 and a second frequency mixer 1113, respectively. The received light emitted from the second coupling port 1102 is divided into two beams of light by a receiving polarization rotation beam splitter, which enter the first frequency mixer 1112 and the second frequency mixer 1113, respectively. The local oscillator light and the received light are mixed by the frequency mixers, so that the demodulation processing of the optical signal is realized. Then, the electrical signals after demodulation are input to the amplifier chip 305 through the first high-speed detector set 1116 and the second high-speed detector set 1114, respectively. After amplification, the electrical signals are input to the digital signal processing chip 302 for processing of the electrical signals, so that the reception of the coherent light is realized.

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

[0104] The other beam of light output by the second output end of the third optical splitter 1107 enters a first quadrature coherent modulator 1108. The second local oscillator sub-light enters a second quadrature coherent modulator 1109. Two beams of light obtain two-way quadrature signal light after being loaded with electrical-optical signals by the first quadrature coherent modulator 1108 and the second quadrature coherent modulator 1109. One-way signal light is obtained by the transmitting polarization rotation beam splitter 1110. The one-way signal light is emitted from the third coupling port 1103, so that the emission of the coherent light is realized.

[0105] Figure 12 A structure of a coherent light chip in an optical module according to some embodiments of the present disclosure Figure 5 As shown in FIG. 1, the coherent light chip includes a laser assembly 900, an amplifier chip 305, a digital signal processing chip 302, a first high-speed detector set 1116, a second high-speed detector set 1114, a first frequency mixer 1112, a second frequency mixer 1113, a first quadrature coherent modulator 1108, a second quadrature coherent modulator 1109, a transmitting polarization rotation beam splitter 1110, a wavelength locker 1106, a directional coupler 1104, a third optical splitter 1107, a second optical splitter 1105, a fourth optical splitter 1115, a receiving polarization rotation beam splitter 1111, a controller 303 and a first coupling port 1101. Figure 12As shown, the optical splitter set 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 with the first coupling port 1101 to receive the local oscillator light output by the laser assembly 900. The second optical splitter 1105 divides the local oscillator light into first local oscillator light and second local oscillator light. The first local oscillator light enters a fourth optical splitter 1115. The fourth optical splitter 1115 divides the first local oscillator light into two beams of light, which enter a first frequency mixer 1112 and a second frequency mixer 1113, respectively. The received light emitted from the second coupling port 1102 is divided into two beams of light by a receiving polarization rotation beam splitter, which enter the first frequency mixer 1112 and the second frequency mixer 1113, respectively. The local oscillator light and the received light are mixed by the frequency mixers, so that the demodulation processing of the optical signal is realized. Then, the demodulated electrical signal is input to the amplifier chip 305 through the first high-speed detector set 1116 and the second high-speed detector set 1114, respectively. After being amplified, the electrical signal is input to the digital signal processing chip 302 for processing of the electrical signal, so that the coherent light is received.

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

[0107] The second local oscillator sub-light enters a first quadrature coherent modulator 1108. Another beam of light output by the first output end of the third optical splitter 1107 enters a second quadrature coherent modulator 1109. After being loaded with electrical-optical signals in the first quadrature coherent modulator 1108 and the second quadrature coherent modulator 1109, the two beams of light obtain two paths of quadrature signal light. The two paths of quadrature signal light obtain one path of signal light through a transmitting polarization rotation beam splitter 1110. The one path of signal light is emitted from the third coupling port 1103, so that the coherent light is emitted.

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

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

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

[0111] The first waveguide 1122 has one end connected to the first output end of the first beam splitter 1120, and the first waveguide 1122 is used to transmit the first beam split.

[0112] The second waveguide 1124 has one end connected to the second output terminal of the first beam splitter 1120. The optical path length of the second waveguide 1124 is greater than that of the first waveguide 1122, and the second waveguide 1124 is used to transmit the second beam. Because the optical path lengths of the first waveguide 1122 and the second waveguide 1124 are different, there is an optical path difference between the first beam splitter and the second beam splitter, which results in a corresponding phase difference between the first beam splitter and the second beam splitter transmitted through the first waveguide 1122 and the second waveguide 1124.

[0113] In some embodiments, the optical path difference between the first waveguide 1122 and the second waveguide 1124 is designed such that the first beam splitter and the second beam splitter transmitted through the first waveguide 1122 and the second waveguide 1124 are 180 degrees out of phase.

[0114] In some embodiments, the wavelength locker 1106 adopts a Mach-Zehnder modulator structure with a dual waveguide structure. Based on the Mach-Zehnder interference principle, the waveform of the output intensity of the output beam at the output end of the wavelength locker 1106 changing with the wavelength of the input beam at the input end is related to the refractive index and optical path length of the first waveguide 1122 and the second waveguide 1124. 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. Therefore, as long as the waveguide design ensures that the difference between the product of the two waveguides (the product of the refractive index and the waveguide length) remains unchanged at different temperatures, the waveform of the output intensity of the output beam at the output end changing with the wavelength of the input beam at the input end remains unchanged at different temperatures, thereby realizing the temperature-insensitive characteristic of the wavelength of the input beam.

[0115] In some embodiments, the first waveguide 1122 can be a silicon waveguide, and the second waveguide 1124 can be a silicon waveguide + silicon nitride waveguide + silicon waveguide. Only the lengths of the first waveguide 1122 and the second waveguide 1124 need to be adjusted so that 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 are different, that is, the wavelength is not sensitive 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 the first end and the second end of the second waveguide 1124 are silicon nitride waveguides, in order to smoothly transmit the preset wavelength light beam between the waveguides of two different materials, the second waveguide 1124 is provided with a second waveguide converter 1123, 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 1122 is correspondingly provided with a first waveguide converter 1121.

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

[0119] In some embodiments, the multimode interference coupler is an optical device that can couple multiple optical modes together to realize the distribution and combination of optical signals. Its principle is based on the interference phenomenon of light, and the phase difference of light waves in the fiber is used to realize the coupling and separation of optical signals.

[0120] The multimode interference coupler is usually composed of two or more optical fibers. When the multimode interference coupler realizes light splitting, at least one optical fiber serves as an input end, and the other optical fiber serves as an output end. In the input end, light waves are divided into multiple modes, each mode has a different propagation path and phase difference. These optical modes interfere with each other inside the coupler to form multiple split lights, 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 condition. When the phase difference of the light waves is an even multiple, the light waves will strengthen each other to form a strong composite light wave. When the phase difference of the light waves is an odd multiple, the light waves will cancel each other 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, so as to achieve different coupling effects.

[0122] The light detector group includes at least two light detectors, which are used to convert the optical signals of the detection light into electrical signals and transmit the electrical signals to the controller 303. The controller 303 can calculate the wavelength of the local oscillator light split into the wavelength locker according to the received electrical signals, so as to calculate the wavelength difference between the wavelength of the local oscillator light and the preset wavelength. The controller 303 feeds back a control signal to the laser assembly 900 according to the wavelength difference, so as to adjust the wavelength of the local oscillator light output by the laser assembly 900, thereby realizing the locking of the wavelength.

[0123] In some embodiments, the multimode interference coupler 1125 can have two input optical ports and two output optical ports. The two input optical ports are connected with the first waveguide 1122 and the second waveguide 1124 respectively, so as 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 interfere in different modes in the multimode interference coupler 1125, and the first detection light and the second detection light are output from the two output optical ports. The phase of the first detection light is different from that of the second detection light, and the phase difference between the first detection light and the second detection light is 90 degrees.

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

[0125] In some embodiments, the multimode interference coupler 1125 may also have two input optical ports and four 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 beam and the second beam with a phase difference into the multimode interference coupler 1125. The first beam and the second beam interfere with each other in different modes within the multimode interference coupler 1125, and output a first probe light, a second probe light, a third probe light and a fourth probe light from the four output optical ports. The phase of the first probe light is 90 degrees different from the phase of the second probe light, the phase of the second probe light is 90 degrees different from the phase of the fourth probe light, and the phase of the fourth probe light is 90 degrees different from the phase of the third probe light. For example, the phase of the first probe light is 0°, the phase of the second probe light is 90°, the phase of the fourth probe light is 180°, and the phase of the third probe light is 270°.

[0126] The photodetector group includes a first photodetector 1126, a second photodetector 1127, a third photodetector 1128, and a fourth photodetector 1129. The first photodetector 1126 converts the optical signal of the first probe light into an electrical signal, the second photodetector 1127 converts the optical signal of the second probe light into an electrical signal, the third photodetector 1128 converts the optical signal of the third probe light into an electrical signal, and the fourth photodetector 1129 converts the optical signal of the fourth probe light into an electrical signal. Then, the first photodetector 1126, the second photodetector 1127, the third photodetector 1128, and the fourth photodetector 1129 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 303 feeds back the wavelength difference information to the laser assembly 900, and controls the laser assembly 900 to adjust the temperature or drive current, thereby stabilizing the wavelength of the local oscillator light output by the laser assembly 900 at the preset wavelength to achieve wavelength locking.

[0127] Figure 14 This is a power curve diagram of a photodetector in an optical module provided according to some embodiments of the present disclosure. For example... Figure 6 and Figure 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 photodetector group. The controller 303 stores the optical power and wavelength relationship curves of the detection light at different phases. For example, Port1: optical power and wavelength relationship curve of 0° detection light, port2: optical power and wavelength relationship curve of 90° detection light, port4: optical power and wavelength relationship curve of 180° detection light, and port3: optical power and wavelength relationship curve of 270° detection light.

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

[0129] When the wavelength locker 1106 outputs two probe lights with a phase difference of 90 degrees, the controller 303 can detect the wavelength according to the optical power ratio of the two probe lights with a phase difference of 90 degrees. For example, the controller 303 calculates that the optical powers of the two probe lights are P1 and P2 respectively, and according to P1 / P2, the wavelength change direction of the preset wavelength light beam is represented.

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

[0131] According to P1 / P2, the deviation direction of the wavelength of the specific wavelength light beam is known, and the controller 303 sends a control signal to the laser assembly 900 to adjust the temperature or driving current of the laser assembly 900, so as to stabilize the wavelength of the laser assembly 900 at a 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 assembly 900 needs to be increased. At this time, the controller 303 can control the temperature of the TEC 907 in the laser assembly 900 to reduce the ambient temperature of the laser 902, thereby increasing the wavelength of the local oscillator light output by the laser assembly 900, until the controller 303 detects that P1 / P2 is equal to 1, so that the wavelength of the local oscillator light output by the laser assembly 900 is stabilized at a specific wavelength.

[0133] When the controller 303 calculates that P1 / P2 is less than 1, it indicates that the wavelength of the input light beam of the wavelength locker 1106 is greater than the preset wavelength, and the wavelength of the output light beam of the laser assembly 900 needs to be reduced. At this time, the controller 303 can control the temperature of the TEC 907 in the laser assembly 900 to increase the ambient temperature of the laser 902, so as to reduce the wavelength of the output light beam of the laser assembly 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 output light beam of the laser assembly 900 by controlling the temperature of the laser assembly 900, but also can control the driving current transmitted to the laser assembly 900 to adjust the wavelength of the output light beam of the laser assembly 900. For example, when the laser 902 increases the driving current, the output wavelength increases, and at this time, 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, so as to increase the wavelength of the output light beam of the laser assembly 900, until the controller 303 detects that P1 / P2 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, so as to reduce the wavelength of the output light beam of the laser assembly 900, until the controller 303 detects that P1 / P2 is equal to 1.

[0135] When the wavelength locker 1106 outputs four detection light beams, and the phases of the four detection light beams are respectively different by 90 degrees, the controller 303 can detect the wavelength according to the light power difference of the two detection light beams with a phase difference of 180 degrees. For example, the controller 303 calculates that the light powers of the four detection light beams are P1, P2, P3, and P4, obtains a first light power difference ΔP1 of P1 and P4, and a second light power difference ΔP2 of P2 and P3, and 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, if the wavelength of the preset wavelength beam outputted by the laser assembly 900 is set as 1538 nm, the controller 303 obtains the wavelength of the input beam of the wavelength locker 1106 as 1538.5 nm according to P1, P2, P3, P4, ΔP1, ΔP2, and according to the curve of the relationship between the optical power and the wavelength, the wavelength of the input beam of the wavelength locker 1106 is 0.5 nm different from the preset wavelength, and the change relationship of port1 is that the optical power gradually increases to the maximum value, the change relationship of port2 is that it gradually increases, the change relationship of port3 is that it gradually decreases, and the change relationship of port4 is that it gradually decreases to the minimum value. The controller 303 feeds back the control signal to the laser assembly 900 to increase the temperature of the TEC 907 or decrease the driving current transmitted to the laser 902, so as to decrease the wavelength of the output beam of the laser assembly 900, until the wavelength of the input 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 beams as P1, P2, P3, and P4, obtains a first optical power ratio K1 of P1 and P4 and a second optical power ratio K2 of P2 and P3, and obtains the wavelength of the input beam of the wavelength locker 1106 according to P1, P2, P3, P4, K1, and K2.

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

[0139] In some embodiments, the two light beams are separated into four probe light beams by a multimode interference coupler 1125 in the wavelength locker 1106, the phases of the four probe light beams are 90 degrees apart, compared with representing the wavelength variation direction of the preset wavelength light beam according to the optical power ratio of the two probe light beams, the controller 303 determines the wavelength of the input light beam of the wavelength locker 1106 according to the optical powers of the four probe light beams and the optical power difference of the two probe light beams whose phases are 180 degrees apart, which can accurately determine the wavelength of the input light beam of the wavelength locker 1106, and determine the wavelength difference between the wavelength of the input light beam of the wavelength locker 1106 and the preset wavelength, thereby determining the approximate range of the laser assembly 900 adjusting the wavelength of the output light beam, for example, how much temperature to raise or lower, or how much driving current to increase or decrease, rather than trial and error.

[0140] The optical module provided by the embodiments of the present disclosure integrates a wavelength locker in a coherent light chip, realizes 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, thereby reducing the packaging complexity of the external light source, and the coherent light chip has both coherent emission and reception functions and integrated wavelength monitoring functions, thereby meeting the requirement of short-distance coherent application scenarios for reducing the line width and wavelength accuracy of the external light source, but being more sensitive to cost.

[0141] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present disclosure, but not to limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for some technical features thereof; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate 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 board; A light source, electrically connected to the circuit board, is used to generate local oscillator light; A coherent optical chip is electrically connected to the circuit board, and the coherent optical chip includes: The first coupling port is connected to the light source, and the first coupling port is used to input the local oscillator light; The beam splitter group has its input end connected to the first coupling port, and the beam splitter group is used to split the local oscillator light into multiple local oscillator beams; A wavelength lock is connected to one output terminal of the beam splitter group. The wavelength lock includes a first waveguide, a second waveguide, and a multimode interference coupler. The first waveguide and the second waveguide have different optical path lengths. The input terminal of the multimode interference coupler is connected to the first waveguide and the second waveguide, respectively. The wavelength lock is used to split one local oscillator beam into two beams. The two beams are transmitted through the first waveguide and the second waveguide, and the multimode interference coupler outputs at least two probe beams with different phases. A controller is mounted on the circuit board and is electrically connected to the coherent optical chip and the light source. The controller is used to acquire the optical power of the at least two probe lights, determine the local oscillator wavelength based on the optical power and the optical power-wavelength relationship curve stored in the controller, and adjust the wavelength of the local oscillator light output by the light source based on the wavelength difference between the local oscillator wavelength and the preset wavelength to achieve wavelength locking.

2. The optical module according to claim 1, characterized in that, The wavelength locker also includes: The first beam splitter has its input end connected to an output end of the beam splitter group. The first beam splitter is used to split one local oscillator beam into a first beam splitter and a second beam splitter. The first waveguide is used to transmit the first beam splitter and the second waveguide is used to transmit the second beam splitter. The multimode interference coupler has at least two output optical ports at its output end, so that the first beam splitter and the second beam splitter interfere to output at least two probe beams with different phases; A photodetector group includes at least two photodetectors, which are used to convert the optical signal of the probe 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 includes four output optical ports. The first beam splitter and the second beam splitter output a first probe beam, a second probe beam, a third probe beam, and a fourth probe beam through the multimode interference coupler. The first probe beam and the second probe beam are 90 degrees out of phase, the second probe beam and the fourth probe beam are 90 degrees out of phase, and the fourth probe beam and the third probe beam are 90 degrees out of phase. The photodetector group includes four photodetectors, which respectively convert the optical signals of the first detection light, the second detection light, the third detection light and the fourth detection light into electrical signals.

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

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

8. The optical module according to claim 1, characterized in that, The beam splitter assembly includes: A directional coupler, the input of which is connected to the first coupling port, and the first output of which is connected to the wavelength lockout; The second beam splitter has its input end connected to the second output end of the directional coupler, and its first output end is connected to the polarization balance detector group. The third beam splitter has its input end connected to the second output end of the second beam splitter, and its output end is connected to a dual coherent modulator.

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

10. An optical module, characterized in that, include: Circuit board; A light source, electrically connected to the circuit board, is used to generate local oscillator light; A coherent optical chip is electrically connected to the circuit board, and the coherent optical chip includes: The first coupling port is connected to the light source, and the first coupling port is used to input the local oscillator light; The beam splitter group has its input end connected to the first coupling port, and the beam splitter group is used to split the local oscillator light into multiple local oscillator beams; A wavelength locker, connected to one output terminal of the beam splitter group, comprises: The first beam splitter has its input end connected to an output end of the beam splitter group. The first beam splitter is used to split one local oscillator beam into a first beam splitter and a second beam splitter. A first waveguide is connected to the first output terminal of the first beam splitter, and the first waveguide is used to transmit the first beam splitting. The second waveguide is connected to the second output terminal of the first beam splitter, and the second waveguide is used to transmit the second beam splitting. A multimode interference coupler has four output optical ports at its output end, so that the first beam splitter and the second beam splitter interfere to output four probe beams with different phases, and the phases are 90 degrees apart. A photodetector group includes four photodetectors, which are used to convert the optical signal of the probe light into an electrical signal; A controller is mounted on the circuit board and is electrically connected to the coherent optical chip and the light source. The controller is used to acquire the optical power of the four probe lights, determine the local oscillator wavelength based on the four optical powers and the optical power-wavelength relationship curve stored in the controller, and adjust the wavelength of the local oscillator light output by the light source based on the wavelength difference between the local oscillator wavelength and the preset wavelength to achieve wavelength locking.

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