An optical module

Abstract

The optical module provided by the present application includes: a circuit board; a light source electrically connected to the circuit board, used to emit light that does not carry a modulation signal; a silicon photonic chip electrically connected to the circuit board, including a Mach-Zehnder electro-optical modulator, a heater, an input optical port and an output optical port, the light that does not carry a modulation signal emitted by the light source enters the Mach-Zehnder electro-optical modulator through the input optical port, and the light that does not carry a signal is modulated into a signal light by the Mach-Zehnder electro-optical modulator, and the heater is arranged on the interference arm of the Mach-Zehnder electro-optical modulator; a signal processing circuit connected to the circuit board, a first output end connected to the heater, and a control signal is output to the heater through the first output end according to the message data, so that the signal light modulated by the Mach-Zehnder electro-optical modulator carries the message data. The optical module provided in the embodiment of the present application is convenient for realizing the auxiliary channel function of the optical module by using the top modulation technology.

Description

Technical Field

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

[0002] With the development of new services and application models such as cloud computing, mobile Internet, and video, the development and progress of optical communication technology has become increasingly important. In optical communication technology, optical modules are tools for realizing the mutual conversion of photoelectric signals and are one of the key components in optical communication equipment. Among them, in tunable optical modules, the use of silicon-based optoelectronics' external cavity laser solution to realize the photoelectric conversion function has become a mainstream solution adopted by high-speed optical modules. Compared with the traditional tunable solution of DBR (Distributed Bragg Reflector) laser + electro-absorption modulator, the external cavity laser solution based on silicon-based optoelectronics has good advantages in terms of low cost, wide tuning range, and low power consumption.

[0003] And with the development of G.metro technology, the optical modules at the head end and the tail end of the G.metro system need to implement a two-way message channel to transmit message data such as equipment control, OAM (Operation Administration and Maintenance) and software upgrades to realize remote equipment management functions. Therefore, the optical module in G.metro needs to have a data transmission function of a two-way message channel, such as wavelength automatic communication function, carrier data channel function, DDM (Digital Diagnostic Monitoring) information transmission function, power-off alarm function, etc. Specifically, for the wavelength communication function, the optical module does not have the function of identifying the wavelength. It is necessary to encode the wavelength data through the head end optical module and send it out through the top adjustment method. The tail end optical module receives and parses the data. After the tail end optical module emits light at the wavelength, it will encode its own wavelength data and then transmit it back to the head end optical module to complete the communication; for DDM information transmission, power-off alarm, etc., the head end optical module also needs to encode the message data, send it out through the top adjustment method, and the tail end optical module receives and parses it. Topping refers to superimposing a small analog or digital signal as a topping service on the service signal at the transmitting end, transmitting it on the optical transmission channel, and completing the data transmission function of the bidirectional message channel of the optical module. Therefore, topping the transmitted optical signal is a necessary way to realize the message channel transmission.

[0004] At present, traditional DBR laser-based optical modules can achieve the top adjustment function by loading a low-frequency signal on the laser's bias current. However, due to the particularity and complexity of silicon photonic external cavity tunable technology, the top adjustment method of traditional optical modules will bring about problems such as wavelength drift of the optical module. Summary of the invention

[0005] The embodiment of the present application provides an optical module to facilitate the use of top adjustment technology to realize the auxiliary channel function of the optical module.

[0006] An optical module provided in an embodiment of the present application includes:

[0007] Circuit boards;

[0008] a light source, electrically connected to the circuit board, and configured to emit light that does not carry a signal;

[0009] A silicon photonic chip is electrically connected to the circuit board, and includes a Mach-Zehnder electro-optical modulator, a heater, an input optical port, and an output optical port. The light not carrying the modulation signal emitted by the light source enters the Mach-Zehnder electro-optical modulator through the input optical port, and the light not carrying the modulation signal is modulated into signal light by the Mach-Zehnder electro-optical modulator. The heater is arranged on the interference arm of the Mach-Zehnder electro-optical modulator.

[0010] A signal processing circuit is electrically connected to the circuit board, and a first output end is connected to the heater. A control signal is output to the heater through the first output end according to the message data, so that the signal light modulated by the Mach-Zehnder electro-optical modulator carries the message data.

[0011] The optical module provided by the present application includes a circuit board, a light source, a silicon photonic chip and a signal processing circuit, wherein the silicon photonic chip includes a Mach-Zehnder electro-optical modulator (MZM), a heater, an input optical port and an output optical port, and the heater is arranged on the interference arm of the MZM, and the MZM is used to modulate the light that does not carry the modulation signal into the signal light, and the first output end of the signal processing circuit is connected to the heater. When the optical module has message data to be transmitted, the signal processing circuit encodes the message data, and then outputs a control signal to the heater through the first output end according to the message data, and the signal light obtained by modulating the Mach-Zehnder electro-optical modulator through the heater carries the message data, and then realizes that in the process of modulating the business signal of the MZM normally, the message data is modulated by the top adjustment method for the secondary modulation of the signal light, and the message data is superimposed on the business signal. Therefore, the optical module provided by the present application, the message data is applied to the heater and the message data is modulated by realizing the MZM, so as to facilitate the use of the top adjustment technology to realize the auxiliary channel function of the optical module. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0013] Figure 1 A schematic diagram of a connection relationship of an optical communication terminal;

[0014] Figure 2 It is a schematic diagram of the structure of an optical network unit;

[0015] Figure 3 A schematic diagram of the structure of an optical module provided in an embodiment of the present application;

[0016] Figure 4 Provide a schematic diagram of the decomposed structure of the optical module for the embodiment of the present application;

[0017] Figure 5 A schematic diagram of the internal structure of an optical module provided in an embodiment of the present application;

[0018] Figure 6 A schematic diagram of the internal structure of an optical module provided in an embodiment of the present application. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0020] One of the core links of fiber-optic communication is the conversion between optical and electrical signals. Fiber-optic communication uses optical signals carrying information to transmit in optical fiber / optical waveguide and other information transmission equipment. The passive transmission characteristics of light in optical fiber / optical waveguide can achieve low-cost and low-loss information transmission; while information processing equipment such as computers use electrical signals. In order to establish an information connection between information transmission equipment such as optical fiber / optical waveguide and information processing equipment such as computers, it is necessary to achieve the conversion between electrical and optical signals.

[0021] Optical modules realize the above-mentioned mutual conversion function of optical and electrical signals in the field of optical fiber communication technology. The mutual conversion of optical signals and electrical signals is the core function of optical modules. Optical modules realize electrical connection with external host computers through the gold fingers on their internal circuit boards. The main electrical connections include power supply, I2C signals, data signals and grounding. The electrical connection method realized by gold fingers has become the mainstream connection method in the optical module industry. Based on this, the definition of pins on gold fingers has formed a variety of industry protocols / specifications. Optical modules are widely used in optical network terminals, data centers and G.metro systems.

[0022] Figure 1 Figure 1 is a schematic diagram of the connection relationship of an optical communication terminal. Figure 1 As shown, the connection of the optical communication terminal mainly includes the interconnection between the optical network terminal 100, the optical module 200, the optical fiber 101 and the network cable 103;

[0023] One end of the optical fiber 101 is connected to the remote server, and one end of the network cable 103 is connected to the local information processing device. The connection between the local information processing device and the remote server is completed by the connection between the optical fiber 101 and the network cable 103; and the connection between the optical fiber 101 and the network cable 103 is completed by the optical network terminal 100 with the optical module 200.

[0024] The optical port of the optical module 200 is connected to the optical fiber 101 to establish a bidirectional optical signal connection with the optical fiber 101; the electrical port of the optical module 200 is connected to the optical network terminal 100 to establish a bidirectional electrical signal connection with the optical network terminal 100; the mutual conversion between the optical signal and the electrical signal is realized inside the optical module, so as to establish an information connection between the optical fiber and the optical network terminal; specifically, the optical signal from the optical fiber is converted into an electrical signal by the optical module and then input into the optical network terminal 100, and the electrical signal from the optical network terminal 100 is converted into an optical signal by the optical module and input into the optical fiber.

[0025] The optical network terminal has an optical module interface 102, which is used to access the optical module 200 and establish a bidirectional electrical signal connection with the optical module 200; the optical network terminal has a network cable interface 104, which is used to access the network cable 103 and establish a bidirectional electrical signal connection with the network cable 103; the optical module 200 and the network cable 103 are connected through the optical network terminal 100. Specifically, the optical network terminal transmits the signal from the optical module to the network cable, and transmits the signal from the network cable to the optical module. The optical network terminal acts as a host computer of the optical module to monitor the operation of the optical module.

[0026] At this point, the remote server establishes a two-way signal transmission channel with the local information processing device through optical fiber, optical module, optical network terminal and network cable.

[0027] Common information processing equipment includes routers, switches, and electronic computers. The optical network terminal is a host computer of the optical module, which provides data signals to the optical module and receives data signals from the optical module. Other common optical module host computers include optical line terminals and servers.

[0028] Figure 2 Figure 1 is a schematic diagram of the optical network terminal structure. Figure 2 As shown, the optical network terminal 100 has a circuit board 105, and a cage 106 is arranged on the surface of the circuit board 105; an electrical connector is arranged inside the cage 106 for connecting to the electrical port of the optical module such as the gold finger; a heat sink 107 is arranged on the cage 106, and the heat sink 107 has protrusions such as fins to increase the heat dissipation area.

[0029] The optical module 200 is inserted into the optical network terminal. Specifically, the electrical port of the optical module is inserted into the electrical connector inside the cage 106 , and the optical port of the optical module is connected to the optical fiber 101 .

[0030] The cage 106 is located on the circuit board, and the electrical connector on the circuit board is wrapped in the cage, so that the electrical connector is arranged inside the cage; the optical module is inserted into the cage, and the optical module is fixed by the cage, and the heat generated by the optical module is conducted to the cage 106, and then diffused through the heat sink 107 on the cage. The fixing structure of the optical module in other forms of the host computer can be similar to the fixing structure of the optical module in the optical network terminal.

[0031] Figure 3 A schematic diagram of an optical module structure provided in an embodiment of the present application is provided. Figure 4 A schematic diagram of the optical module decomposition structure is provided for the embodiment of the present application. Figure 3 , Figure 4 As shown, the optical module 200 provided in the embodiment of the present application includes an upper housing 201 , a lower housing 202 , an unlocking component 203 , a circuit board 300 , a light emitting component 400 and a light receiving component 500 .

[0032] The upper shell 201 is covered on the lower shell 202 to form a wrapping cavity with two openings; the outer contour of the wrapping cavity is generally a square body. Specifically, the lower shell 202 includes a main board and two side panels located on both sides of the main board and perpendicular to the main board; the upper shell 201 includes a cover plate, which is covered on the two side panels of the lower shell 202 to form a wrapping cavity; the upper shell 201 may also include two side walls located on both sides of the cover plate and perpendicular to the cover plate, and the two side walls are combined with the two side panels to achieve the upper shell 201 covering the lower shell 202.

[0033] The two openings can specifically be two end openings (204, 205) in the same direction, or two openings in different directions; one of the openings is an electrical port 204, and the gold finger of the circuit board extends from the electrical port 204 and is inserted into a host computer such as an optical network terminal; the other opening is an optical port 205, which is used for external optical fiber access to connect the silicon photonic chip 410 inside the optical module; optoelectronic devices such as the circuit board 300, the optical transmitting component 400 and the optical receiving component 500 are located in the encapsulating cavity.

[0034] The upper shell and the lower shell are combined to facilitate installation of components such as the circuit board 300, the optical transmitting component 400 and the optical receiving component 500 into the shell. The upper shell and the lower shell form the outermost packaging protection shell of the optical module. The upper shell and the lower shell are generally made of metal materials, which is conducive to electromagnetic shielding and heat dissipation. The shell of the optical module is generally not made into an integrated component. In this way, when assembling components such as circuit boards, positioning components, heat dissipation and electromagnetic shielding components cannot be installed, which is not conducive to production automation.

[0035] The unlocking component 203 is located on the outer wall of the cavity / lower shell 202 and is used to achieve a fixed connection between the optical module and the host computer, or to release the fixed connection between the optical module and the host computer.

[0036] The unlocking component 203 has a locking component that matches the cage of the host computer; pulling the end of the unlocking component can make the unlocking component move relatively on the surface of the outer wall; the optical module is inserted into the cage of the host computer, and the locking component of the unlocking component fixes the optical module in the cage of the host computer; by pulling the unlocking component, the locking component of the unlocking component moves accordingly, thereby changing the connection relationship between the locking component and the host computer, so as to release the locking relationship between the optical module and the host computer, so that the optical module can be pulled out of the cage of the host computer.

[0037] Circuit traces, electronic components (such as capacitors, resistors, transistors, MOS tubes) and chips (such as MCU, clock data recovery CDR, power management chip, data processing chip DSP) are arranged on the circuit board 300.

[0038] The circuit board connects the electrical components in the optical module according to the circuit design through circuit routing to achieve electrical functions such as power supply, electrical signal transmission and grounding.

[0039] Circuit boards are generally rigid circuit boards. Rigid circuit boards can also perform load-bearing functions due to their relatively hard material. For example, rigid circuit boards can stably carry chips. When optical transceivers are located on the circuit boards, rigid circuit boards can also provide stable load-bearing. Rigid circuit boards can also be inserted into electrical connectors in the cage of the host computer. Specifically, metal pins / gold fingers are formed on the end surface of one side of the rigid circuit board for connecting to the electrical connector. These are not easy to achieve with flexible circuit boards.

[0040] Flexible circuit boards are also used in some optical modules as a supplement to rigid circuit boards. Flexible circuit boards are generally used in conjunction with rigid circuit boards. For example, flexible circuit boards can be used to connect rigid circuit boards to optical transceiver devices.

[0041] The optical transmitting submodule and the optical receiving submodule can be collectively referred to as an optical submodule. Figure 4As shown, the optical module provided in the embodiment of the present application includes an optical transmitting submodule 400 and an optical receiving submodule 500, and the optical transmitting submodule 400 and the optical receiving submodule 500 are electrically connected to the circuit board 300. Optionally, the optical transmitting submodule 400 and the optical receiving submodule 500 are located at the ends of the circuit board 300, and the optical transmitting submodule 400 and the optical receiving submodule 500 are physically separated from the circuit board 300. The optical transmitting submodule 400 and the optical receiving submodule 500 can be connected to the circuit board 300 through flexible circuit boards, respectively.

[0042] Figure 5 This is a schematic diagram of the internal structure of an optical module provided in an embodiment of the present application. Figure 5 As shown, the optical emission submodule 400 provided in the embodiment of the present application includes a silicon photonic chip 410 and a light source 420. The silicon photonic chip 410 receives light from the light source 420, and the silicon photonic chip 410 receives light from the light source 420 through an optical fiber. The silicon photonic chip 410 modulates the light, specifically by loading a signal onto the light. The light modulated by the silicon photonic chip 410 is transmitted to an external optical fiber through an optical port.

[0043] In the embodiment of the present application, in order to complete the modulation of light, the silicon photonic chip 410 includes an MZM, and the MZM includes two interference arms, which are called the first interference arm and the second interference arm for the convenience of description, and the first interference arm and the second interference arm are respectively provided with modulation electrodes. The light emitted by the light source 4200 is input to the MZM, and the signal light is obtained by implementing the signal modulation of the light through the modulation electrode.

[0044] Further, in an embodiment of the present application, a heater is provided on the first interfering arm or the second interfering arm, and the heater is used for heating the first interfering arm or the second interfering arm. In addition, a heater may be provided on the first interfering arm and the second interfering arm respectively, but considering the limitation of the number of pins of the silicon photonic chip 410, a heater is provided on the first interfering arm or the second interfering arm, such as a heater is provided on the first interfering arm. When there is message data to be transmitted in the optical module, the signal processing circuit encodes the message data to obtain a control signal with a certain frequency, and the signal processing circuit outputs the control signal through the first output end and applies it to the heater, and the heating intensity of the heater will increase or decrease with a certain frequency and rule, and when the heating intensity of the heater changes, the temperature of the interfering arm changes, and the refractive index of the interfering arm changes, so as to realize the loading modulation of the message data signal on the first interfering arm. In an embodiment of the present application, the heater may be a heating device such as a heating resistor or a thermocouple. In an embodiment of the present application, the message data may be generated by the optical module according to its working mechanism, such as the MCU in the optical module is generated according to the working mechanism of the optical module, or it may be transmitted to the optical module by the host computer through the I2C pin of the optical module. Message data refers to communication data between terminals, which is used for communication between terminals. When the optical module needs to send message data given by the host computer, the host computer transmits the message data to the signal processing circuit, and the signal processing circuit further processes the message data after receiving the message data.

[0045] At the same time, when using MZM to modulate the service optical signal, it is necessary to stabilize the MZM at the optimal working point first, that is, it is necessary to ensure that the first interferometer arm and the second interferometer arm on the MZM have a constant phase difference of π / 2. Therefore, after modulating the signal light in the MZM, the MZM divides the signal light beam into output light and monitoring light. The output light is used to transmit the optical module, and the monitoring light is used to monitor the optical power emitted by the optical module; the light intensity of the output light needs to be 1 / 2MZM modulation to obtain the light intensity of the signal light, and then the light intensity of the output light and the light intensity of the monitoring light need to be equal. However, due to the constraints of the MZM's own structural factors, it is easily affected by its own temperature and external environment, which leads to unstable working point. Therefore, when the MZM deviates from the optimal working point, the heating intensity of the heater is adjusted to change the phase of the light on the first interferometer arm or the second interferometer arm, reduce the light intensity difference between the output light and the monitoring light, and then maintain the MZM at the working point. Therefore, in an embodiment of the present application, the silicon photonic chip 410 also includes a detection circuit, which outputs a detection signal to the signal processing circuit. The signal processing circuit drives the heater through the second output terminal according to the received detection signal to maintain the MZM at the working point.

[0046] In an embodiment of the present application, the detection circuit includes a first sampling circuit and a second sampling circuit, and the first sampling circuit and the second sampling circuit are used to detect the light intensity of the output light and the monitoring light. Specifically, an input optical port and an output optical port are set on the silicon photonic chip 410, and the light without signal emitted by the light source enters the MZM through the input optical port, and the MZM modulates the light without signal into signal light and divides the signal light into output light and monitoring light. The first sampling circuit and the second sampling circuit detect and compare the output light and the monitoring light and output sampling voltages respectively, and each sampling voltage corresponds to the light intensity of the output light and the light intensity of the monitoring light. The output light is output from the silicon photonic chip 410 through the output optical port. Alternatively, the detection circuit includes a DMPD (Differential monitorphotodiode, monitoring photodiode unit) detection circuit, and the detection signal is obtained through the DMPD detection circuit. The signal processing circuit may include an MCU; or include an MCU, an operational amplifier or a comparator, etc.

[0047] like Figure 5 As shown, in the optical module provided by the embodiment of the present application, MCU301 is arranged on the circuit board. Among them, MCU301 is connected to the gold finger, and the message data sent by the host computer can be received through the I2C gold finger in the gold finger. The first output end of MCU301 is connected to the heater, and MCU301 transmits the control signal generated according to the encoded information data to the heater through the output end; at the same time, the input end of MCU301 is connected to the output end of the first sampling circuit and the output end of the second sampling circuit, and MCU301 receives the sampling voltage output by the first sampling circuit and the second sampling circuit, and outputs the driving voltage to the heater through the second output end according to the received sampling voltage. Therefore, the optical module provided by the embodiment of the present application can complete the adjustment of the message data on the business data through the heater set on the MZM interference wall, and at the same time stabilize the MZM at the optimal working point.

[0048] According to the received sampling voltage, a driving voltage is output to the heater. Optionally, MCU301 compares the sampling voltages obtained by the first sampling circuit and the second sampling circuit, and adjusts the voltage applied to the heater according to the comparison result to control the heating intensity of the heater. When the sampling voltage output by the first sampling circuit is different from the sampling voltage output by the second sampling circuit, that is, the light intensity of the output light and the light intensity of the monitoring light are different, the voltage applied to the heater is increased or decreased. Alternatively, the sampling voltages obtained by the first sampling circuit and the second sampling circuit are first transmitted to the MCU after being operated by an operational amplifier or a comparator, and the MCU then adjusts the voltage applied to the heater according to the result of the operation of the operational amplifier or the comparator to control the heating intensity of the heater.

[0049] The optical module provided in this application is described in detail below with reference to specific examples.

[0050] Figure 6 This is a schematic diagram of the internal structure of an optical module provided in an embodiment of the present application. Figure 6 As shown, the silicon photonic chip 410 includes an MZM 411, a first sampling circuit 412, and a second sampling circuit 413. The silicon photonic chip 410 also includes an input optical port and an output optical port. The input optical port is used for the light source 420 to send light that does not carry a signal into the silicon photonic chip 410, and the output optical port is used to output the signal light modulated and split by the MZM 411. The signal processing circuit includes an MCU 301, and the MCU 301 is used to realize the information data top adjustment control and the maintenance control of the optimal working point.

[0051] like Figure 6 As shown, MZM411 includes a first optical splitter, a first interference arm, a second interference arm, a first modulation electrode, a second modulation electrode, a heater, a light combiner, a second optical splitter, a third optical splitter and a fourth optical splitter. The input end of the first optical splitter is connected to the light source 420 through an optical fiber ribbon to receive the light input from the light source 420 to the silicon photonic chip 410; the first output end of the first optical splitter is connected to the input end of the first interference arm, and the second output end is connected to the input end of the second interference arm. The first optical splitter divides the received light into two and transmits them to the first interference arm and the second interference arm respectively. A first modulation electrode is arranged on the first interference arm, and the first modulation electrode is used for the first interference arm to modulate the light input to the first interference arm; a second modulation electrode is arranged on the second interference arm, and the second modulation electrode acts on the second interference arm to modulate the light input to the second interference arm; the first modulation electrode and the second modulation electrode are used to modulate the service signal on the light input to MZM411. The heater is arranged on the first interference arm, and the MCU301 applies the message data signal and the heater driving voltage to the heater, and the heater message data signal is modulated and loaded into the light transmitted on the first interference arm, and the heater heats the first interference arm according to the received driving voltage. The output end of the first interference arm and the output end of the second interference arm are respectively connected to the input end of the light combiner, and the light combiner combines the light inputted from the first interference arm and the second interference arm; the output end of the light combiner is connected to the input end of the second beam splitter, the first output end of the second beam splitter is connected to the input end of the third beam splitter, and the second output end of the second beam splitter is connected to the input end of the fourth beam splitter; the first output end of the third beam splitter is connected to the output light port, that is, outputs the optical signal carrying the top adjustment information data, and the second output end of the third beam splitter is used to transmit the split light to the first sampling circuit 412; the second output end of the fourth beam splitter transmits the split light to the second sampling circuit 413. In this embodiment, the second beam splitter splits the light input to the light combiner into output light and monitoring light, and the third beam splitter and the fourth beam splitter are used to implement the first sampling circuit 412 and the second sampling circuit 413 to detect and compare the intensity of the output light and the intensity of the monitoring light.

[0052] Specifically, the third optical splitter splits a certain proportion of light from the output light to the first sampling circuit 412, such as the third optical splitter splits 2%, 3% ... of light from the output light to the first sampling circuit 412; the fourth optical splitter splits the same proportion of light from the monitoring light to the second sampling circuit 413. Optionally, the third optical splitter splits 2% of light from the output light to the first sampling circuit 412, and the fourth optical splitter splits 2% of light from the monitoring light to the second sampling circuit 413. The first sampling circuit 412 receives the output light output from the second output end of the third optical splitter, and the second sampling circuit 413 receives the monitoring light output from the first output end of the fourth optical splitter. The first sampling circuit 412 generates a first photocurrent according to the received output light and outputs a first sampling voltage through the output end, and the second sampling circuit 413 generates a second photocurrent according to the monitoring hole and outputs a second sampling voltage through the output end. The first sampling voltage reflects the light intensity of the output light, and the second sampling voltage reflects the light intensity of the monitoring light. The first sampling voltage output by the first sampling circuit 412 is input to the first analog-to-digital conversion interface (ADC1) of the MCU301, and the first analog-to-digital conversion interface converts the first sampling voltage of the analog signal into the first sampling voltage of the digital signal; the second sampling voltage output by the second sampling circuit 413 is input to the second analog-to-digital conversion interface (ADC2) of the MCU301, and the second analog-to-digital conversion interface converts the second sampling voltage of the analog signal into the second sampling voltage of the digital signal. The MCU301 calculates and compares the magnitudes of the first sampling voltage and the second sampling voltage, and outputs the driving voltage to the heater through the second digital-to-analog conversion interface according to the calculation and comparison results. At the same time, the MCU301 adjusts the driving voltage output through the second digital-to-analog conversion interface according to the first sampling voltage and the second sampling voltage monitored in real time.

[0053] In the embodiment of the present application, the first sampling circuit 412 and the second sampling circuit 413 respectively include a photodetector and a sampling resistor, and the corresponding photodetector is used to receive output light or monitoring light. Optionally: the first sampling circuit 412 includes a first photodetector and a first sampling resistor, the output end of the first photodetector is connected to one end of the first sampling resistor, the other end of the first sampling resistor is grounded, the output end of the first photodetector is the output end of the first sampling circuit, and the first photodetector receives the signal light output from the first output end of the third spectrometer; the second sampling circuit includes a second photodetector and a second sampling resistor, the output end of the second photodetector is connected to one end of the second sampling resistor, the other end of the second sampling resistor is grounded, the output end of the second photodetector is the output end of the second sampling circuit, and the second photodetector receives the signal light output from the second output end of the fourth spectrometer. The first photodetector receives the signal light output from the first output end of the third spectrometer and converts the light into a photocurrent, and converts the photocurrent into a voltage signal through a first sampling resistor and transmits the first sampling voltage to the first analog-to-digital conversion interface of MCU301; the second photodetector receives the signal light output from the second output end of the fourth spectrometer and converts the light into a photocurrent, and converts the photocurrent into a voltage signal through a second sampling resistor and transmits the second sampling voltage to the second analog-to-digital conversion interface of MCU301.

[0054] When MCU301 receives the message data sent by the host computer, MCU301 encodes the message data, outputs a low-frequency control signal according to the encoded message data, and then transmits the control signal to the heater through the first digital-to-analog conversion interface (DAC1) of MCU301. Specifically, MCU301 converts the low-frequency signal of the message data from a digital signal to an analog signal through the first digital-to-analog conversion interface and transmits it to the heater.

[0055] In an embodiment of the present application, in order to enable MCU301 to apply a voltage to the heater through the second digital-to-analog conversion interface to control the heating intensity of the heater, optionally, MCU301 receives a first sampling voltage through the first analog-to-digital conversion interface and a second sampling voltage received through the second analog-to-digital conversion interface, and compares the first sampling voltage with the second sampling voltage; if the first sampling voltage is greater than the second sampling voltage (the light intensity of the output light is greater than the light intensity of the monitoring light), the voltage applied to the heater is reduced; if the first sampling voltage is less than the second sampling voltage (the light intensity of the output light is less than the light intensity of the monitoring light), the voltage applied to the heater is increased. Then, MCU301 adjusts the voltage applied to the heater through the second digital-to-analog conversion interface (DAC2) according to the sampling voltage output by the first sampling circuit 412 and the second sampling circuit 413. The change of the voltage applied to the heater will affect the change of the signal amplitude and phase of the photodetector in the sampling circuit, thereby forming a closed-loop feedback control loop. The entire loop will dynamically stabilize the MZM411 between tiny voltage increases and decreases at the optimal operating point, realize automatic compensation of the DC bias of the MZM411 at any time, and ensure that the MZM411 is dynamically stable at the optimal operating point.

[0056] Specifically: the first analog-to-digital conversion interface determines the first sampling voltage of the digital signal by matching the first sampling voltage of the analog signal received with the value in the lookup table set inside MCU301, and the second analog-to-digital conversion interface determines the second sampling voltage of the digital signal by matching the second sampling voltage of the analog signal received with the value in the lookup table set inside MCU301; compare the first sampling voltage of the digital signal and the second sampling voltage of the digital signal; if the first sampling voltage is greater than the second sampling voltage, reduce the voltage applied to the heater; if the first sampling voltage is less than the second sampling voltage, increase the voltage applied to the heater; if the first sampling voltage is equal to the second sampling voltage, maintain the voltage applied to the heater at the last moment.

[0057] like Figure 6As shown, the business signal is a high-frequency signal, and the encoded message data is a low-frequency signal. The business signal and the encoded message data usually differ by several orders of magnitude, and the amplitude of the message data is slightly larger than the amplitude of the business signal; when MZM411 works normally, the driving voltage applied to the heater by MCU301 is constant during the driving voltage adjustment cycle. Then, when the message data and the driving voltage are applied to the heater at the same time, the two signals of the message data and the driving voltage are superimposed, and finally the signal applied to the heater increases or decreases at a certain frequency based on a certain initial value, forming a new signal acting on the heater, realizing the second modulation of the light on the first interference arm. In the embodiment of the present application, in order to prevent the message data from affecting the transmission of the business signal, the top modulation depth of the message data is usually about 10%, and the optional top modulation depth of the message data is 6%. The frequency of the encoded message data is usually set by the equipment operator, and MCU301 encodes the message data according to the specified frequency.

[0058] In this embodiment, if the light intensity of the output light is greater than the light intensity of the monitoring light, the first sampling voltage is greater than the second sampling voltage, and the MCU301 reduces the voltage applied to the heater according to the first step, and the first step is greater than 0. Optionally, the first step is 0.01V, 0.02V, 0.05V, etc. Further, the MCU301 determines how much the first sampling voltage is greater than the second sampling voltage, and selects to reduce the amount of voltage applied to the heater, that is, dynamically selects the first step according to how much the first sampling voltage is greater than the second sampling voltage. For example: when the first sampling voltage is greater than the second sampling voltage by a large amount, the MCU301 selects a relatively large first step to reduce the voltage applied to the heater; when the first sampling voltage is less than the second sampling voltage, the MCU301 selects a relatively small first step to reduce the voltage applied to the heater. Assuming that the first sampling voltage is greater than the second sampling voltage by 0.5V, the MCU301 selects a first step of 0.03V to reduce the voltage applied to the heater, then when the first sampling voltage is greater than the second sampling voltage by 0.1V, the MCU301 can select a first step of 0.01V to reduce the voltage applied to the heater.

[0059] In this embodiment, if the light intensity of the output light is less than the light intensity of the monitoring light, the first sampling voltage is less than the second sampling voltage, and the MCU301 increases the voltage applied to the heater according to the first step, and the second step is greater than 0. Optionally, the second step is 0.01V, 0.02V, 0.05V, etc. Further, the MCU301 determines how much the first sampling voltage is less than the second sampling voltage, and chooses to increase the amount of voltage applied to the heater, that is, dynamically selects the second step according to how much the first sampling voltage is less than the second sampling voltage. For example: when the first sampling voltage is much less than the second sampling voltage, the MCU301 selects a relatively large second step to increase the voltage applied to the heater; when the first sampling voltage is less than the second sampling voltage, the MCU301 selects a relatively small second step to increase the voltage applied to the heater. Assuming that the first sampling voltage is less than the second sampling voltage by 0.5V, the MCU301 selects a second step of 0.03V to increase the voltage applied to the heater, then when the first sampling voltage is less than the second sampling voltage by 0.1V, the MCU301 can select a second step of 0.01V to increase the voltage applied to the heater.

[0060] In the embodiment of the present application, the signal processing circuit compares the first sampling voltage and the second sampling voltage through a comparison unit in the MCU301; or, compares the first sampling voltage and the second sampling voltage through an operational amplifier or a comparator.

[0061] Further, in the embodiment of the present application, the silicon photonic chip 410 further includes a third photodetector 414, which receives the signal light outputted from the second output end of the fourth optical splitter, and monitors the emission light power of the optical module according to the signal light. Optionally, the photocurrent output end of the third photodetector 414 is connected to a sampling circuit, which is connected to the MCU301, and the sampling circuit converts the photocurrent into a voltage signal and transmits it to the MCU301, which determines the emission light power of the optical module according to the received voltage signal.

[0062] In the embodiment of the present application, the heater may also be arranged on the second interferometer arm. If the heater is arranged on the second interferometer arm, the low-frequency signal of the message data is converted from a digital signal to an analog signal through the first digital-to-analog conversion interface and transmitted to the heater; and in combination with the settings of the first sampling circuit 412 and the second sampling circuit 413, the MCU301 control logic is adjusted to perform the second modulation of the light on the second interferometer arm and maintain the MZM in the silicon photonic chip at the optimal working point.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An optical module, characterized in that: include: Circuit boards; a light source, electrically connected to the circuit board, and configured to emit light that does not carry a modulation signal; A silicon photonic chip is electrically connected to the circuit board, and includes a Mach-Zehnder electro-optical modulator, a heater, an input optical port, and an output optical port. Light that does not carry a modulation signal emitted by the light source enters the Mach-Zehnder electro-optical modulator through the input optical port, and the Mach-Zehnder electro-optical modulator modulates the light that does not carry a signal into signal light. The heater is disposed on an interference arm of the Mach-Zehnder electro-optical modulator. The signal processing circuit comprises an MCU; the MCU is electrically connected to the circuit board, receives message data and encodes the message data, wherein the message data is a low-frequency signal; the MCU comprises a first output terminal, and the first output terminal is connected to the heater; the MCU outputs a control signal to the heater through the first output terminal based on the message data, so as to load the message data into the signal light modulated by the Mach-Zehnder electro-optical modulator, so that the Mach-Zehnder electro-optical modulator outputs the signal light carrying the high-frequency signal and the low-frequency signal.

2. The optical module according to claim 1, characterized in that: The silicon photonic chip further includes a detection circuit, and the detection circuit outputs a detection signal to the MCU; The MCU also includes a second output terminal, which is connected to the heater and outputs a driving signal to drive the heater according to the detection signal, so that the Mach-Zehnder electro-optic modulator is stabilized at a working point.

3. The optical module according to claim 2, characterized in that: The detection circuit includes a first sampling circuit and a second sampling circuit; the Mach-Zehnder electro-optical modulator includes a first beam splitter, a first interference arm, a second interference arm, a light combiner, a second beam splitter, a third beam splitter and a fourth beam splitter; The input end of the first beam splitter is connected to the input light port; the input end of the first interference arm and the input end of the second interference arm are respectively connected to the first output end and the second output end of the first beam splitter; the heater is arranged on the first interference arm or the second interference arm; the output end of the first interference arm and the output end of the second interference arm are respectively connected to the light combiner; the output end of the light combiner is connected to the input end of the second beam splitter; The first output end of the second optical splitter is connected to the input end of the third optical splitter, the second output end of the second optical splitter is connected to the input end of the fourth optical splitter, and the second optical splitter equally divides the signal light inputted by the optical combiner into the third optical splitter and the fourth optical splitter; The first output end of the third optical splitter is connected to the output optical port, the second output end of the third optical splitter is used to split the signal light outputted from the first output end of the second optical splitter into a beam of signal light of N% to the first sampling circuit, and the second end of the fourth optical splitter is used to split the signal light outputted from the second output end of the second optical splitter into a beam of signal light of N% to the second sampling circuit, where N is a positive number less than 100; The output end of the first sampling circuit and the output end of the second sampling circuit are respectively connected to the MCU. The MCU applies a voltage to the heater to control the heating intensity of the heater according to the monitoring signals obtained through the first sampling circuit and the second sampling circuit, so that the Mach-Zehnder electro-optic modulator is stabilized at an optimal operating point.

4. The optical module according to claim 3, characterized in that: The first sampling circuit includes a first photodetector and a first sampling resistor, the output end of the first photodetector is connected to one end of the first sampling resistor, the other end of the first sampling resistor is grounded, the first photodetector receives the signal light output by the first output end of the third optical splitter, and the first analog-to-digital conversion interface of the MCU is connected between the output end of the first photodetector and one end of the first sampling resistor; The second sampling circuit includes a second photodetector and a second sampling resistor, the output end of the second photodetector is connected to one end of the second sampling resistor, the other end of the second sampling resistor is grounded, the second photodetector receives the signal light output by the second output end of the fourth spectrometer, and the second analog-to-digital conversion interface of the MCU is connected between the output end of the second photodetector and one end of the second sampling resistor.

5. The optical module according to claim 3, characterized in that: The silicon photonic chip further includes a third photodetector, which receives the signal light outputted from the first output end of the fourth optical splitter and monitors the emission light power of the optical module according to the signal light.

6. The optical module according to claim 3, characterized in that: The MCU applies a voltage to the heater to control the heating intensity of the heater according to the monitoring signal obtained by the first sampling circuit and the second sampling circuit, including: The MCU compares the voltages obtained by the first sampling circuit and the second sampling circuit, and adjusts the voltage applied to the heater according to the comparison result to control the heating intensity of the heater.

7. The optical module according to claim 6, characterized in that: The heater is disposed on the first interference arm; and the voltage applied to the heater is adjusted according to the comparison result to control the heating intensity of the heater, comprising: if the voltage obtained by the first sampling circuit is greater than the voltage obtained by the second sampling circuit, reducing the voltage applied to the heater; If the voltage obtained by the first sampling circuit is lower than the voltage obtained by the second sampling circuit, the voltage applied to the heater is increased.

8. The optical module according to claim 7, characterized in that: If the voltage obtained by the first sampling circuit is greater than the voltage obtained by the second sampling circuit, reducing the voltage applied to the heater comprises: If the voltage obtained by the first sampling circuit is greater than the voltage obtained by the second sampling circuit, the voltage applied to the heater is reduced according to a first step, and the first step is greater than zero.

9. The optical module according to claim 7, characterized in that: If the voltage obtained by the first sampling circuit is less than the voltage obtained by the second sampling circuit, increasing the voltage applied to the heater comprises: If the voltage obtained by the first sampling circuit is less than the voltage obtained by the second sampling circuit, the voltage applied to the heater is increased according to a second step, and the second step is greater than zero.

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