CN114114558A - Optical module - Google Patents

Abstract

The application provides an optical module, includes: a circuit board; the light source is electrically connected with the circuit board and used for emitting light which does not carry modulation signals; the silicon optical chip is electrically connected with the circuit board and comprises a Mach-Zehnder electro-optic modulator, a heater, an input optical port and an output optical port, light which is emitted by a light source and does not carry modulation signals enters the Mach-Zehnder electro-optic modulator through the input optical port, the light which does not carry signals is modulated into signal light through the Mach-Zehnder electro-optic modulator, and the heater is arranged on an interference arm of the Mach-Zehnder electro-optic modulator; and the signal processing circuit is connected with the circuit board, the first output end of the signal processing circuit is connected with the heater, and a control signal is output to the heater through the first output end according to the message data, so that the message data is carried in the signal light obtained by modulation of the Mach-Zehnder electro-optic modulator. The optical module provided by the embodiment of the application is convenient to realize the auxiliary channel function of the optical module by adopting a top-adjusting technology.

Description

Optical module

Technical Field

The application relates to the technical field of optical fiber communication, in particular to an optical module.

Background

With the development of new services and application modes such as cloud computing, mobile internet, video and the like, the development and progress of the optical communication technology become increasingly important. In the optical communication technology, an optical module is a tool for realizing the interconversion of optical signals and is one of the key devices in optical communication equipment. In the tunable optical module, the scheme of using an external cavity laser of silicon-based photoelectrons to realize the photoelectric conversion function has become a mainstream scheme adopted by the high-speed optical module. Compared with the traditional tunable scheme of a DBR (distributed Bragg Reflector) laser and an electro-absorption modulator, the scheme of the external cavity laser based on silicon-based photoelectrons has the advantages of low cost, wide tuning range, low power consumption and the like.

With the development of the g.metro technology, the optical modules at the head end and the tail end in the g.metro system need to implement a bidirectional message channel to perform transmission of message data such as device management and control, OAM (Operation Administration and Maintenance), and upgrade software, so as to implement a remote device management function. Therefore, the optical module in g.metro needs to have a data transmission function of bidirectional message channel, such as a wavelength automatic pair communication function, a carrier data channel function, a DDM (Digital Diagnostic Monitoring) information transmission function, a power failure alarm function, and the like. Specifically, for the wavelength communication function, the optical module does not have the function of identifying the wavelength, the head-end optical module is required to send out the wavelength data codes in a top-adjusting mode, the tail-end optical module analyzes the data after receiving the data, and the tail-end optical module transmits the coded wavelength data of the tail-end optical module to the head-end optical module after emitting light with the wavelength, so that the communication is completed; for DDM information transmission, power failure alarm, etc., the head-end optical module is also required to encode message data, send out the message data in a top-tuning manner, and receive and analyze the message data by the tail-end optical module. The top-tuning means that a small-amplitude analog or digital signal is superimposed on a service signal at a transmitting end to serve as a top-tuning service, and the top-tuning service is transmitted on an optical transmission channel to complete the data transmission function of a bidirectional message channel of an optical module. Therefore, the tuning of the emitted optical signal is a necessary way to realize the message channel transmission.

At present, the traditional optical module based on the DBR laser can realize the function of tuning the top by loading a low-frequency signal on the bias current of the laser, but aiming at the particularity and complexity of the silicon optical external cavity tunable technology, the tuning mode of the traditional optical module can bring the problems of the wavelength drift of the optical module and the like.

Disclosure of Invention

The embodiment of the application provides an optical module to conveniently adopt a top-adjusting technology to realize the auxiliary channel function of the optical module.

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

a circuit board;

the light source is electrically connected with the circuit board and is used for emitting light which does not carry signals;

the silicon optical chip is electrically connected with the circuit board and comprises a Mach-Zehnder electro-optic modulator, a heater, an input optical port and an output optical port, light which is emitted by the light source and does not carry modulation signals enters the Mach-Zehnder electro-optic modulator through the input optical port, the light which does not carry modulation signals is modulated into signal light through the Mach-Zehnder electro-optic modulator, and the heater is arranged on an interference arm of the Mach-Zehnder electro-optic modulator;

and the signal processing circuit is electrically connected with the circuit board, the first output end of the signal processing circuit is connected with the heater, and a control signal is output to the heater through the first output end according to message data, so that the message data is carried in signal light obtained by modulation of the Mach-Zehnder electro-optic modulator.

The application provides an optical module, including circuit board, light source, silicon optical chip and signal processing circuit, the silicon optical chip includes mach-zehnder electro-optic modulator (MZM), heater, input light mouth and output light mouth, and the heater setting is on MZM's interference arm, and MZM is used for not carrying the light modulation of modulation signal to signal light, and signal processing circuit's first output is connected the heater. When message data need to be transmitted, the signal processing circuit encodes the message data, then outputs a control signal to the heater through the first output end according to the message data, and enables the message data to be carried in signal light obtained by modulation of the Mach-Zehnder electro-optic modulator through the heater, so that secondary modulation of the signal light is performed on the message data in a top-modulation mode in the process of modulating a service signal in normal operation of the MZM, and the message data is superposed on the service signal. Therefore, in the optical module provided by the application, the message data is applied to the heater and modulated on the MZM, and then the function of the auxiliary channel of the optical module is conveniently realized by adopting a tuning top technology.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic diagram of a connection relationship of an optical communication terminal;

FIG. 2 is a schematic diagram of an optical network unit;

fig. 3 is a schematic structural diagram of an optical module according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of an exploded structure of an optical module according to an embodiment of the present application;

fig. 5 is a schematic diagram of an internal structure of an optical module according to an embodiment of the present application;

fig. 6 is a schematic view of an internal structure of an optical module according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

One of the core links of optical fiber communication is the interconversion of optical and electrical signals. The optical fiber communication uses optical signals carrying information to transmit in information transmission equipment such as optical fibers/optical waveguides, and the information transmission with low cost and low loss can be realized by using the passive transmission characteristic of light in the optical fibers/optical waveguides; meanwhile, the information processing device such as a computer uses an electric signal, and in order to establish information connection between the information transmission device such as an optical fiber or an optical waveguide and the information processing device such as a computer, it is necessary to perform interconversion between the electric signal and the optical signal.

The optical module realizes the function of interconversion of optical signals and electrical signals in the technical field of optical fiber communication, and the interconversion of the optical signals and the electrical signals is the core function of the optical module. The optical module is electrically connected with an external upper computer through a golden finger on an internal circuit board of the optical module, and the main electrical connection comprises power supply, I2C signals, data signals, grounding and the like; the electrical connection mode realized by the gold finger has become the mainstream connection mode of the optical module industry, and on the basis of the mainstream connection mode, the definition of the pin on the gold finger forms various industry protocols/specifications. Optical modules are widely used in optical network terminals, data centers and g.metro systems.

Fig. 1 is a schematic diagram of a connection relationship of an optical communication terminal. As shown in fig. 1, the connection of the optical communication terminal mainly includes the interconnection among the optical network terminal 100, the optical module 200, the optical fiber 101 and the network cable 103;

one end of the optical fiber 101 is connected with a far-end server, one end of the network cable 103 is connected with local information processing equipment, and the connection between the local information processing equipment and the far-end 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 made by the optical network terminal 100 having the optical module 200.

An optical port of the optical module 200 is externally accessed to the optical fiber 101, and establishes bidirectional optical signal connection with the optical fiber 101; an electrical port of the optical module 200 is externally connected to the optical network terminal 100, and establishes bidirectional electrical signal connection with the optical network terminal 100; the optical module realizes the interconversion of optical signals and electric signals, thereby realizing the establishment of 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 to 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 to the optical fiber.

The optical network terminal is provided with an optical module interface 102, which is used for accessing an optical module 200 and establishing bidirectional electric signal connection with the optical module 200; the optical network terminal is provided with a network cable interface 104, which is used for accessing the network cable 103 and establishing bidirectional electric signal connection with the network cable 103; the optical module 200 is connected to the network cable 103 through the optical network terminal 100, specifically, the optical network terminal transmits a signal from the optical module to the network cable and transmits the signal from the network cable to the optical module, and the optical network terminal serves as an upper computer of the optical module to monitor the operation of the optical module.

At this point, a bidirectional signal transmission channel is established between the remote server and the local information processing device through the optical fiber, the optical module, the optical network terminal and the network cable.

Common information processing apparatuses include routers, switches, electronic computers, and the like; the optical network terminal is an upper computer of the optical module, provides data signals to the optical module, and receives the data signals from the optical module.

Fig. 2 is a schematic diagram of an optical network terminal structure. As shown in fig. 2, the optical network terminal 100 has a circuit board 105, and a cage 106 is disposed on a surface of the circuit board 105; an electric connector is arranged in the cage 106 and used for connecting an electric port of an optical module such as a golden finger; the cage 106 is provided with a heat sink 107, and the heat sink 107 has a projection such as a fin that increases a heat radiation area.

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.

The cage 106 is positioned on the circuit board, and the electrical connector on the circuit board is wrapped in the cage, so that the electrical connector is arranged in the cage; the optical module is inserted into the cage, held by the cage, and the heat generated by the optical module is conducted to the cage 106 and then diffused by the heat sink 107 on the cage. The fixed structure of the optical module in the upper computer in other forms can be similar to that of the optical module in the optical network terminal.

Fig. 3 is a schematic view of an optical module according to an embodiment of the present disclosure, and fig. 4 is a schematic view of an exploded structure of an optical module according to an embodiment of the present disclosure. As shown in fig. 3 and 4, an optical module 200 provided in an embodiment of the present application includes an upper housing 201, a lower housing 202, an unlocking member 203, a circuit board 300, a light emitting module 400, and a light receiving module 500.

The upper shell 201 is covered on the lower shell 202 to form a wrapping cavity with two openings; the outer contour of the package cavity generally presents a square shape, and specifically, the lower housing 202 includes a main board and two side boards located at two sides of the main board and arranged perpendicular to the main board; the upper shell 201 comprises a cover plate which covers two side plates of the lower shell 202 to form a wrapping cavity; the upper casing 201 may further include two side walls disposed at two sides of the cover plate and perpendicular to the cover plate, and the two side walls are combined with the two side plates to cover the upper casing 201 on the lower casing 202.

The two openings may be two ends (204, 205) in the same direction, or two openings in different directions; one opening is an electric port 204, and a gold finger of the circuit board extends out of the electric port 204 and is inserted into an upper computer such as an optical network terminal; the other opening is an optical port 205 for external optical fiber access to connect with a silicon optical chip 410 inside the optical module; the optoelectronic devices such as the circuit board 300, the light emitting assembly 400 and the light receiving assembly 500 are positioned in the package cavity.

The assembly mode of combining the upper shell and the lower shell is adopted, so that the circuit board 300, the light emitting assembly 400, the light receiving assembly 500 and other devices can be conveniently installed in the shells, and the outermost packaging protection shell of the optical module is formed by the upper shell and the lower shell; the upper shell and the lower shell are made of metal materials generally, so that electromagnetic shielding and heat dissipation are facilitated; generally, the housing of the optical module is not made into an integrated component, so that when devices such as a circuit board and the like are assembled, the positioning component, the heat dissipation component and the electromagnetic shielding component cannot be installed, and the production automation is not facilitated.

The unlocking component 203 is located on the outer wall of the wrapping cavity/lower shell 202, and is used for realizing the fixed connection between the optical module and the upper computer or releasing the fixed connection between the optical module and the upper computer.

The unlocking component 203 is provided with a clamping component matched with the upper computer cage; the end of the unlocking component can be pulled to enable the unlocking component to move relatively on the surface of the outer wall; the optical module is inserted into a cage of the upper computer, and the optical module is fixed in the cage of the upper computer by a clamping component of the unlocking component; by pulling the unlocking component, the clamping component of the unlocking component moves along with the unlocking component, so that the connection relation between the clamping component and the upper computer is changed, the clamping relation between the optical module and the upper computer is released, and the optical module can be drawn out from the cage of the upper computer.

The circuit board 300 is provided with circuit traces, electronic components (such as capacitors, resistors, triodes, and MOS transistors), and chips (such as an MCU, a clock data recovery CDR, a power management chip, and a data processing chip DSP).

The circuit board connects the electrical appliances in the optical module together according to the circuit design through circuit wiring to realize the functions of power supply, electrical signal transmission, grounding and the like.

The circuit board is generally a hard circuit board, and the hard circuit board can also realize a bearing effect due to the relatively hard material of the hard circuit board, for example, the hard circuit board can stably bear a chip; when the optical transceiver is positioned on the circuit board, the rigid circuit board can also provide stable bearing; the hard circuit board can also be inserted into an electric connector in the upper computer cage, and specifically, a metal pin/golden finger is formed on the surface of the tail end of one side of the hard circuit board and is used for being connected with the electric connector; these are not easily implemented with flexible circuit boards.

A flexible circuit board is also used in a part of the optical module to supplement a rigid circuit board; the flexible circuit board is generally used in combination with a rigid circuit board, for example, the rigid circuit board may be connected to the optical transceiver device through the flexible circuit board.

The tosa and the rosa may be collectively referred to as an optical subassembly. As shown in fig. 4, the optical module provided in the embodiment of the present application includes a tosa 400 and a rosa 500, and the tosa 400 and the rosa 500 are electrically connected to a circuit board 300. Alternatively, the tosa 400 and the rosa 500 are located at the end of the circuit board 300, and the tosa 400 and the rosa 500 are physically separated from the circuit board 300. The tosa 400 and the rosa 500 may be connected to the circuit board 300 through flexible circuit boards, respectively.

Fig. 5 is a schematic view of an internal structure of an optical module according to an embodiment of the present application. As shown in fig. 5, the tosa 400 according to the embodiment of the present invention includes a silicon photonic chip 410 and a light source 420. Silicon photonic chip 410 receives light from light source 420 and silicon photonic chip 410 receives light from light source 420 through an optical fiber. The silicon optical chip 410 modulates light, and particularly loads a signal onto the light. The light modulated by the silicon optical chip 410 is transmitted to an external optical fiber through an optical port.

In the embodiment of the present application, to complete the modulation of light, the silicon optical chip 410 includes an MZM, and the MZM includes two interference arms, which are referred to as a first interference arm and a second interference arm for convenience of description, and the first interference arm and the second interference arm are respectively provided with modulation electrodes. Light emitted from the light source 4200 is input to the MZM, and signal light is obtained by performing signal modulation of the light by the modulation electrode.

Further, in the embodiment of the present application, a heater is provided on the first interference arm or the second interference arm, and the heater is used for heating the first interference arm or the second interference arm. In addition, the first interference arm and the second interference arm can be respectively provided with a heater, but the first interference arm or the second interference arm is provided with a heater, for example, the first interference arm is provided with a heater, in consideration of the limitation of the pin number of the silicon optical chip 410. When the optical module has message data to be transmitted, the signal processing circuit encodes the message data to obtain a control signal with a certain frequency, the signal processing circuit outputs the control signal through the first output end and applies the control signal to the heater, the heating intensity of the heater is increased or decreased according to a certain frequency and rule, when the heating intensity of the heater is changed, the temperature of the interference arm is changed, the refractive index of the interference arm is changed, and the loading modulation of the message data signal on the first interference arm is realized. In the embodiment of the present application, the heater may be a heating device such as a heating resistor, a thermocouple, or the like. In this embodiment of the application, the message data may be generated by the optical module according to a working mechanism thereof, for example, the MCU in the optical module generates according to the working mechanism of the optical module, or the upper computer transmits the message data to the optical module through the I2C pin of the optical module. The message data is communication data between terminals and is used for communication between the terminals. When the optical module needs to send message data given by the upper computer, the upper computer transmits the message data to the signal processing circuit, and the signal processing circuit receives the message data and then further processes the message data.

Meanwhile, when the MZM is used to modulate a service optical signal, the MZM needs to be stabilized at an optimal operating point, that is, it needs to be ensured that the first interference arm and the second interference arm on the MZM have a phase difference of pi/2. Therefore, after the signal light is obtained by modulation in the MZM, the MZM converts the signal light beam into output light and monitoring light, the output light is used for transmitting the optical module, and the monitoring light is used for monitoring the optical power emitted by the optical module; the light intensity of the output light needs to be 1/2MZM modulated 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 restriction of the self-structure factor of the MZM, the MZM is easily interfered by the self-temperature and the external environment, and thus the operating point is unstable. Therefore, when the MZM deviates from the optimal working point, the heating intensity of the heater is adjusted, so that the phase of the light on the first interference arm or the second interference arm is changed, the light intensity difference between the output light and the monitoring light is reduced, and the MZM is maintained at the working point. Therefore, in the embodiment of the present application, the silicon optical chip 410 further includes a detection circuit, the detection circuit outputs a detection signal to the signal processing circuit, and the signal processing circuit drives the heater through the second output terminal according to the received detection signal, so as to maintain the MZM at the operating point.

In an embodiment of the present application, the detection circuit includes a first sampling circuit and a second sampling circuit for detecting the light intensities of the output light and the monitor light. Specifically, set up input optical port and output optical port on silicon optical chip 410, the light that does not carry the signal that the light source sent gets into MZM through the input optical port, MZM will not carry the light modulation of signal for signal light and will signal light divide into output light and control light, first sampling circuit and second sampling circuit detect and compare output light and control light and export sampling voltage respectively, the light intensity of the corresponding reaction output light of each sampling voltage and the light intensity of control light, output light is through output optical port output silicon optical chip 410. Alternatively, the detection circuit includes a DMPD (Differential monitor photodiode unit) detection circuit, and the detection signal is obtained by the DMPD detection circuit. The signal processing circuit may include an MCU; or comprises an MCU, an operational amplifier or a comparator and the like.

As shown in fig. 5, in the optical module provided in the embodiment of the present application, the MCU301 is disposed on a circuit board. The MCU301 is connected with the golden fingers, and can receive message data sent by the upper computer through I2C golden fingers in the golden fingers. A first output end of the MCU301 is connected with the heater, and the MCU301 transmits and loads a control signal generated according to the encoded information data to the heater through the output end; meanwhile, the input end of the MCU301 is connected to the output end of the first sampling circuit and the output end of the second sampling circuit, and the MCU301 receives the sampling voltages output by the first sampling circuit and the second sampling circuit and outputs a driving voltage to the heater through the second output end according to the received sampling voltages. Therefore, the optical module provided by the embodiment of the application can finish tuning of message data on service data through the heater arranged on the interference wall of the MZM, and can stabilize the MZM at an optimal working point.

The MCU301 outputs a driving voltage to the heater according to the received sampling voltage, and optionally, compares the sampling voltages obtained by the first and second sampling circuits, and adjusts a 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, namely the light intensity of the output light is different from the light intensity of the monitoring light, the voltage applied to the heater is increased or decreased. Or the sampling voltages obtained by the first sampling circuit and the second sampling circuit are firstly operated by the operational amplifier or the comparator and then transmitted to the MCU, and the MCU further adjusts the voltage applied to the heater according to the result of the operation of the operational amplifier or the comparator so as to control the heating intensity of the heater.

The optical module provided in the present application is described in detail below with reference to specific examples.

Fig. 6 is a schematic view of an internal structure of an optical module according to an embodiment of the present application. As shown in fig. 6, the silicon biochip 410 includes an MZM411, a first sampling circuit 412, and a second sampling circuit 413. The silicon optical chip 410 further comprises an input optical port and an output optical port, the input optical port is used for light which is emitted by the light source 420 and does not carry signals into the silicon optical chip 410, and the output optical port is used for outputting signal light modulated and split by the MZM 411. The signal processing circuit comprises an MCU301, and information data set-top control and maintenance control of an optimal working point are realized through the MCU 301.

As shown in fig. 6, MZM411 includes a first optical splitter, a first interference arm, a second interference arm, a first modulation electrode, a second modulation electrode, a heater, an optical combiner, a second optical splitter, a third optical splitter, and a fourth optical splitter. The input end of the first optical splitter is connected with a light source 420 through an optical fiber ribbon and receives light input into the silicon optical chip 410 by the light source 420; the first output end of the first optical splitter is connected with the input end of the first interference arm, the second output end of the first optical splitter is connected with the input end of the second interference arm, and the first optical splitter divides the received light into two parts which are respectively transmitted to the first interference arm and the second interference arm. A first modulation electrode is arranged on the first interference arm and used for modulating the light input into the first interference arm by the first interference arm; a second modulation electrode is arranged on the second interference arm and acts on the second interference arm to modulate the light input into the second interference arm; the first and second modulation electrodes are used to up-modulate the traffic signal to the light in the input MZM 411. The heater is disposed on the first interference arm, the MCU301 applies a message data signal and a heater driving voltage to the heater, the heater message data signal is modulated into 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 with the input end of the light combiner, and the light combiner combines the light input to the first interference arm and the light input to the second interference arm; the output end of the light combiner is connected with the input end of the second light splitter, the first output end of the second light splitter is connected with the input end of the third light splitter, and the second output end of the second light splitter is connected with the input end of the fourth light splitter; a first output end of the third optical splitter is connected to the output optical port, that is, outputs an optical signal carrying the ceiling-tuning information data, and a second output end of the third optical splitter is used for transmitting the split light to the first sampling circuit 412; a second output of the fourth beam splitter transmits the split light to the second sampling circuit 413. In this embodiment, the second splitter splits the light input to the light combiner into the output light and the monitoring light, and the third splitter and the fourth splitter are used to implement the first sampling circuit 412 and the second sampling circuit 413 for detecting and comparing the light intensity of the output light and the light intensity of the monitoring light.

Specifically, the third optical splitter splits a certain proportion of light from the output light to the first sampling circuit 412, for example, the third optical splitter splits 2% and 3% … … proportion of light from the output light to the first sampling circuit 412; the fourth splitter splits the same proportion of light from the monitoring light to the second sampling circuit 413. Optionally, the third splitter splits 2% of the output light to the first sampling circuit 412, and the fourth splitter splits 2% of the output light to the second sampling circuit 413. The first sampling circuit 412 receives the output light output from the second output terminal of the third splitter and the monitoring light output from the first output terminal of the fourth splitter by the second sampling circuit 413, the first sampling circuit 412 generates a first photocurrent according to the received output light and outputs a first sampling voltage through the output terminal, and the second sampling circuit 413 generates a second photocurrent according to the monitoring hole and outputs a second sampling voltage through the output terminal, wherein 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 a 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 a first sampling voltage of the digital signal; the second sampling voltage output by the second sampling circuit 413 is input to a 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 a second sampling voltage of the digital signal. The MCU301 calculates and compares the first sampling voltage and the second sampling voltage, outputs a driving voltage to the heater through the second DAC interface according to the calculation and comparison result, and simultaneously adjusts the driving voltage output through the second DAC interface according to the first sampling voltage and the second sampling voltage monitored in real time.

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 for receiving output light or monitoring light. Optionally: the first sampling circuit 412 comprises a first photoelectric detector and a first sampling resistor, the output end of the first photoelectric detector is connected with one end of the first sampling resistor, the other end of the first sampling resistor is grounded, the output end of the first photoelectric detector is connected with the output end of the first sampling circuit, and the first photoelectric detector receives signal light output by the first output end of the third optical splitter; the second sampling circuit comprises a second photoelectric detector and a second sampling resistor, the output end of the second photoelectric detector is connected with one end of the second sampling resistor, the other end of the second sampling resistor is grounded, the output end of the second photoelectric detector is connected with the output end of the second sampling circuit, and the second photoelectric detector receives signal light output by the second output end of the fourth optical splitter. The first photoelectric detector receives signal light output by the first output end of the third optical splitter and converts the signal light into photocurrent, and the photocurrent is converted into a voltage signal through the first sampling resistor, and a first sampling voltage is transmitted to the first analog-to-digital conversion interface of the MCU 301; the second photodetector receives the signal light output by the second output terminal of the fourth optical splitter and converts the signal light into a photocurrent, and the photocurrent is converted into a voltage signal through the second sampling resistor, and the voltage signal is transmitted to the second analog-to-digital conversion interface of the MCU 301.

When the MCU301 receives the message data transmitted from the upper computer, the MCU301 performs message data encoding, outputs a low frequency control signal according to the encoded message data, and transmits and loads the control signal to the heater through the first digital-to-analog conversion interface (DAC1) of the MCU 301. Specifically, the MCU301 converts the low-frequency signal of the message data from a digital signal to an analog signal through the first dac interface, and applies the converted signal to the heater.

In this embodiment of the application, in order to enable the 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, the MCU301 compares a first sampling voltage received through the first analog-to-digital conversion interface with 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), reducing the voltage applied to the heater; 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. Furthermore, the MCU301 adjusts the voltage applied to the heater through the second digital-to-analog conversion interface (DAC2) according to the output sampling voltages of the first sampling circuit 412 and the second sampling circuit 413, and 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, which will dynamically stabilize the MZM411 between a small increase and decrease of the voltage at the optimal operating point, thereby implementing automatic compensation of the dc bias of the MZM411 at any time, and ensuring that the MZM411 is dynamically stabilized at the optimal operating point.

Specifically, the method comprises the following steps: the first analog-to-digital conversion interface corresponds a first sampling voltage of a received analog signal to a value in a lookup table set inside the MCU301 to determine a first sampling voltage of a digital signal, and the second analog-to-digital conversion interface corresponds a second sampling voltage of the received analog signal to a value in a lookup table set inside the MCU301 to determine a second sampling voltage of the digital signal; comparing the magnitude of a first sampling voltage of the digital signal with the magnitude of a second sampling voltage of the digital signal; if the first sampling voltage is greater than the second sampling voltage, reducing the voltage applied to the heater; if the first sampling voltage is less than the second sampling voltage, increasing the voltage applied to the heater; if the first sampling voltage is equal to the second sampling voltage, the voltage applied to the heater at the previous moment is maintained.

As shown in fig. 6, the service signal is a high-frequency signal, the encoded message data is a low-frequency signal, the difference between the service signal and the encoded message data is usually several orders of magnitude, and the amplitude of the message data is slightly larger than that of the service signal; when the MZM411 operates normally, the driving voltage applied to the heater by the MCU301 during the driving voltage adjustment period is constant. When the message data and the driving voltage are simultaneously applied to the heater, the message data and the driving voltage are superposed, and finally the signal applied to the heater is increased or decreased at a certain frequency on the basis of a certain initial value to form a new signal to act on the heater, so that the second modulation on the light on the first interference arm is realized. In the embodiment of the present application, in order to prevent the message data from affecting the transmission of the service signal, the message data vertex adjustment depth is usually about 10%, and the optional message data vertex adjustment depth is 6%. The frequency of the encoded message data is typically set by the device operator, and the MCU301 encodes the message data according to the specified frequency.

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 decreases the voltage applied by the heater by a first step, which is greater than 0. Optionally, the first step is 0.01V, 0.02V, 0.05V, etc. Further, the MCU301 determines how much the first sampled voltage is greater than the second sampled voltage, and selects to decrease the amount of voltage applied to the heater, i.e., dynamically selects the first step according to how much the first sampled voltage is greater than the second sampled voltage. Such as: when the first sampling voltage is more than the second sampling voltage, the MCU301 selects a relatively large first further decrease in the voltage applied to the heater; when the first sampled voltage is greater than the second sampled voltage and smaller, the MCU301 selects a relatively smaller first step down to reduce the voltage applied to the heater. Assuming that the first sampling voltage is greater than the second sampling voltage by 0.5V and the MCU301 selects a first further decrease of 0.03V to apply the voltage to the heater, the MCU301 may select a first further decrease of 0.01V to apply the voltage to the heater when the first sampling voltage is greater than the second sampling voltage by 0.1V.

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, the MCU301 increases the voltage applied by the heater by 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 sampled voltage is less than the second sampled voltage, and selects to increase the amount of voltage applied to the heater, i.e., dynamically selects the second step according to how much the first sampled voltage is less than the second sampled voltage. Such as: when the first sampling voltage is less than the second sampling voltage by a large amount, the MCU301 selects a relatively large second step to increase the applied voltage to the heater; when the first sampling voltage is smaller than the second sampling voltage, the MCU301 selects a relatively small second step to increase the applied voltage to the heater. Assuming that the first sampling voltage is less than the second sampling voltage by 0.5V and the MCU301 selects the second step increase of 0.03V to apply the voltage to the heater, the MCU301 may select the second step increase of 0.01V to apply the voltage to the heater when the first sampling voltage is less than the second sampling voltage by 0.1V.

In the embodiment of the present application, the signal processing circuit implements comparison between the first sampling voltage and the second sampling voltage by using a comparison unit in the MCU 301; alternatively, the comparison of the magnitudes of the first and second sampling voltages is achieved by an operational amplifier or a comparator.

Further, in this embodiment, the silicon optical chip 410 further includes a third photodetector 414, where the third photodetector 414 receives the signal light output by the second output terminal of the fourth optical splitter, and monitors the emitted optical power of the optical module according to the signal light. Optionally, a photocurrent output end of the third photodetector 414 is connected to a sampling circuit, the sampling circuit is connected to the MCU301, the sampling circuit converts the photocurrent into a voltage signal and transmits the voltage signal to the MCU301, and the MCU301 determines the emitted optical power of the optical module according to the received voltage signal.

In embodiments of the present application, the heater may also be disposed on the second interference arm. If the heater is arranged on the second interference arm, the low-frequency signal of the message data is converted from a digital signal into an analog signal through the first digital-to-analog conversion interface and is transmitted and loaded to the heater; and adjusting the control logic of the MCU301 in conjunction with the settings of the first sampling circuit 412 and the second sampling circuit 413 to perform a second modulation of the light on the second interferometric arm and maintain the MZM in the silicon photonic chip at the optimal operating point.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims (10)

1. A light module, comprising:

a circuit board;

the light source is electrically connected with the circuit board and used for emitting light which does not carry modulation signals;

the silicon optical chip is electrically connected with the circuit board and comprises a Mach-Zehnder electro-optic modulator, a heater, an input optical port and an output optical port, light which is emitted by the light source and does not carry modulation signals enters the Mach-Zehnder electro-optic modulator through the input optical port, the light which does not carry signals is modulated into signal light through the Mach-Zehnder electro-optic modulator, and the heater is arranged on an interference arm of the Mach-Zehnder electro-optic modulator;

and the signal processing circuit is electrically connected with the circuit board, the first output end of the signal processing circuit is connected with the heater, and a control signal is output to the heater through the first output end according to message data, so that the message data is carried in signal light obtained by modulation of the Mach-Zehnder electro-optic modulator.

2. The optical module of claim 1, wherein the silicon optical chip further comprises a detection circuit, the detection circuit outputting a detection signal to the signal processing circuit;

the signal processing circuit further comprises a second output end, the second output end is connected with the heater, and a driving signal is output according to the detection signal to drive the heater, so that the Mach-Zehnder electro-optic modulator is stabilized at an operating point.

3. The optical module of claim 2, wherein the detection circuit comprises a first sampling circuit and a second sampling circuit; the Mach-Zehnder electro-optic modulator comprises a first optical splitter, a first interference arm, a second interference arm, an optical combiner, a second optical splitter, a third optical splitter and a fourth optical splitter;

the input end of the first optical splitter is connected with the input port; the input end of the first interference arm and the input end of the second interference arm are respectively connected with the first output end and the second output end of the first optical splitter; the heater is disposed 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 with the light combiner; the output end of the light combiner is connected with the input end of the second light splitter;

a first output end of the second optical splitter is connected with an input end of the third optical splitter, a second output end of the second optical splitter is connected with an input end of the fourth optical splitter, and the second optical splitter divides the signal light input to the second optical splitter by the optical combiner into the third optical splitter and the fourth optical splitter in a split manner;

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 for splitting the signal light output by the first output end of the second optical splitter into a beam of signal light with the concentration of N% to the first sampling circuit, the second end of the fourth optical splitter is used for splitting the signal light output by the second output end of the second optical splitter into a beam of signal light with the concentration of N% to the second sampling circuit, and N is a positive number smaller than 100;

the output end of the first sampling circuit and the output end of the second sampling circuit are respectively connected with the signal processing circuit, and the signal processing circuit applies voltage to the heater according to monitoring signals obtained by the first sampling circuit and the second sampling circuit to control the heating intensity of the heater, so that the Mach-Zehnder electro-optic modulator is stabilized at an optimal working point.

4. The optical module according to claim 3, wherein the first sampling circuit includes a first photodetector and a first sampling resistor, an output terminal of the first photodetector is connected to one end of the first sampling resistor, another end of the first sampling resistor is grounded, an output terminal of the first photodetector is an output terminal of the first sampling circuit, and the first photodetector receives the signal light output from the first output terminal of the third optical splitter;

the second sampling circuit comprises a second photoelectric detector and a second sampling resistor, the output end of the second photoelectric detector is connected with one end of the second sampling resistor, the other end of the second sampling resistor is grounded, the output end of the second photoelectric detector is connected with the output end of the second sampling circuit, and the second photoelectric detector receives signal light output by the second output end of the fourth optical splitter.

5. The optical module as claimed in claim 3, wherein the silicon optical chip further includes a third photodetector, the third photodetector receives the signal light output from the first output terminal of the fourth optical splitter, and the emitted optical power of the optical module is monitored according to the signal light.

6. The optical module according to claim 3, wherein the signal processing circuit controls the heating intensity of the heater by applying a voltage to the heater according to the monitoring signal obtained by the first sampling circuit and the second sampling circuit, and includes:

the signal processing circuit compares the magnitudes of 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 light module of claim 6, wherein the heater is disposed on the first interference arm; adjusting a voltage applied to the heater according to the comparison result to control a heating intensity of the heater, including:

reducing the voltage applied to the heater if the voltage obtained by the first sampling circuit is greater than the voltage obtained by the second sampling circuit;

if the voltage obtained by the first sampling circuit is smaller than the voltage obtained by the second sampling circuit, the voltage applied to the heater is increased.

8. The optical module of claim 7, wherein reducing the voltage applied to the heater if the voltage obtained by the first sampling circuit is greater than the voltage obtained by the second sampling circuit 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 by a first step, the first step being greater than 0.

9. The optical module according to claim 7, wherein increasing the voltage applied to the heater if the voltage obtained by the first sampling circuit is smaller than the voltage obtained by the second sampling circuit 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 in a second step, the second step being greater than 0.

10. The light module of claim 1, wherein the signal processing circuit comprises an MCU.

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