Optical module

Abstract

The optical module provided by the invention comprises a circuit board, a light source, an optical modulation chip, a first optical power detection assembly, a second optical power detection assembly, a comparison circuit and an MCU. Due to the property of the optical modulation chip, an optical power detection assembly cannot be integrated in the optical modulation chip, so that a first optical power detection assembly and a second optical power detection assembly are respectively arranged outside the optical modulation chip. According to the application, the hardware structure is kept unchanged, and the compensation voltage is input to the comparison circuit through the MCU, so that the comparison voltage is ensured to be non-negative voltage and is monitored by the MCU. For the same optical module, the value of the compensation voltage is a fixed value, and continuous output of the compensation voltage is maintained. Meanwhile, by adjusting the bias voltage provided for the phase converter, the difference value between the first detection voltage and the second detection voltage is adjusted to the preset difference value, then the comparison voltage is adjusted to the preset voltage, and the working point of the light modulator is adjusted to the optimal working point.

Description

Technical Field

[0001] The present application relates to the field of optical 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 advancement of optical communication technology has become increasingly important. In optical communication technology, optical modules, as one of the key components in optical communication equipment, can realize the conversion of optical and electrical signals. In the development of optical communication technology, the data transmission rate of optical modules is required to be continuously improved.

[0003] In some optical modules, an MZ (Mach-Zehnder) modulator is integrated in the modulation chip. The optical carrier signal reaching the MZ modulator is divided into two beams of light with exactly the same amplitude and frequency and transmitted through the upper and lower branches. A modulation voltage is applied to the modulation area. Due to the electro-optical induction, the refractive index of the modulator material is changed, resulting in a phase difference between the two branch signals. When the phase difference is π / 2, the relative output light intensity of the MZ modulator is linearly related to the electrode voltage. At this time, the dynamic range and conversion efficiency of the output signal are both at the maximum. The working state at this time is called the optimal working point of the MZ modulator.

[0004] Affected by the change in the operating temperature of the modulator, the optimal operating point of the modulator will drift, resulting in adverse effects such as deterioration of the output signal quality and increase in the bit error rate. Summary of the invention

[0005] The present application provides an optical module to lock an optical modulator inside the optical module at an optimal working point.

[0006] The optical module provided in this application includes:

[0007] Circuit boards;

[0008] A light source, electrically connected to the circuit board, for emitting light that does not carry a signal;

[0009] An optical modulation chip is electrically connected to the circuit board and includes an optical modulator, and the optical modulation chip is used to modulate light that does not carry a signal into signal light; wherein the optical modulator includes a phase converter;

[0010] A first optical power detection component is arranged outside the optical modulation chip and on the light input side of the optical modulator;

[0011] A second optical power detection component is arranged outside the optical modulation chip and on the light output side of the optical modulator. When the difference between the first detection voltage and the second detection voltage is a preset difference, the optical module is in a preset state, and the positive and negative values ​​of the corresponding differences of different optical modules are different; wherein the first detection voltage is the detection voltage of the first optical power detection component, and the second detection voltage is the detection voltage of the second optical power detection component;

[0012] A comparison circuit, wherein the first input terminal receives the second detection voltage, and the second input terminal receives the first detection voltage and the compensation voltage output by the MCU; the comparison circuit is used to output a comparison voltage according to the first detection voltage, the second detection voltage and the compensation voltage; when the comparison voltage is a preset voltage, the optical module is in a preset state; when the comparison voltage is a negative voltage, it cannot be monitored;

[0013] The MCU is electrically connected to the circuit board and is configured to input a compensation voltage to the comparison circuit when the optical module is in a preset state so that the comparison voltage is a non-negative voltage while maintaining the output compensation voltage; and when monitoring that the comparison voltage is not a preset voltage, adjust the bias voltage provided to the phase converter so that the difference between the first detection voltage and the second detection voltage is a preset difference, thereby adjusting the comparison voltage to the preset voltage.

[0014] The optical module provided in the present application includes a circuit board, a light source, an optical modulation chip, a first optical power detection component, a second optical power detection component, a comparison circuit and an MCU. Among them, the light source is used to emit light that does not carry a signal; the optical modulation chip is used to modulate the light that does not carry a signal into a signal light. The optical modulation chip includes an optical modulator, and the optical modulator includes a phase converter. Due to the nature of the optical modulation chip itself, the optical power detection component cannot be integrated inside the optical modulation chip. Therefore, the first optical power detection component and the second optical power detection component are respectively arranged outside the optical modulation chip, and the first optical power detection component is located on the light input side of the optical modulator, and the second optical power detection component is located on the light output side of the optical modulator. The voltage detected by the first optical power detection component is the first detection voltage; the voltage detected by the second optical power detection component is the second detection voltage. The first input end of the comparison circuit receives the second detection voltage, and the second input end receives the first detection voltage and the compensation voltage output by the MCU. Since the comparison voltage cannot be monitored by the MCU when it is a negative voltage, and since the first optical power detection component and the second optical power detection component are attached to the outside of the optical modulation chip, there is a patch tolerance, which easily leads to the comparison voltage being a negative voltage. In some embodiments, the comparison voltage is usually monitored by replacing the resistor, and replacing the resistor is bound to increase the production cost. For this reason, the present application inputs a compensation voltage to the comparison circuit through the MCU, and the compensation voltage can compensate for the voltage deviation caused by the patch, thereby ensuring that the comparison voltage is a non-negative voltage, so that it is monitored by the MCU. For the same optical module, the value of the compensation voltage is a fixed value, and the continuous output of the compensation voltage is maintained. In order to lock the operating point of the optical modulator at the optimal operating point, the present application adjusts the optical module to a preset state, maintains the output compensation voltage, and sets the comparison voltage at this time to a preset voltage. If the comparison voltage is not a preset voltage when monitored, it means that the operating point of the optical modulator is not at the optimal operating point. At this time, the bias voltage provided to the phase converter is adjusted so that the difference between the first detection voltage and the second detection voltage is a preset difference, so that the comparison voltage reaches the preset voltage, and the operating point of the optical modulator is adjusted to the optimal operating point. In the present application, by maintaining the output compensation voltage, under the action of the compensation voltage, the comparison voltage is adjusted to a non-negative voltage, so that it can be monitored by the MCU; at the same time, the compensation voltage participates in the locking of the working point. Under the compensation voltage, the difference between the first detection voltage and the second detection voltage is adjusted to a preset difference by adjusting the bias voltage provided to the phase converter, and then the comparison voltage is modulated to a preset voltage, and the working point of the optical modulator is adjusted to the optimal working point. Under the premise of keeping the hardware structure unchanged, the present application provides a compensation voltage to the comparison circuit through the MCU, thereby avoiding the replacement of resistors, and realizing that the comparison voltage is monitored by the MCU from the software, and at the same time, the compensation voltage participates in the locking of the working point; it can reduce production costs and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the present disclosure, the following briefly introduces the drawings used in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the product involved in the embodiments of the present disclosure, the actual process of the method, the actual timing of the signal, etc.

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

[0017] Figure 2 is a partial structural diagram of a host computer according to some embodiments;

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

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

[0020] Figure 5 is a diagram of the internal structure of an optical module according to some embodiments;

[0021] Figure 6 is a structural diagram of an optical modulation chip according to some embodiments;

[0022] Figure 7 is a structural diagram of a first optical power detection component according to some embodiments;

[0023] Figure 8 is a structural diagram of a second optical power detection component according to some embodiments;

[0024] Fig. 9 is a structural diagram of a comparison circuit according to some embodiments;

[0025] Fig.10 A schematic diagram of interaction between an MCU and a phase converter according to some embodiments. DETAILED DESCRIPTION

[0026] In optical communication technology, in order to establish information transmission between information processing devices, it is necessary to load information onto light and use the propagation of light to achieve information transmission. Here, the light loaded with information is an optical signal. When optical signals are transmitted in information transmission equipment, the loss of optical power can be reduced, so high-speed, long-distance, and low-cost information transmission can be achieved. The signals that information processing equipment can recognize and process are electrical signals. Information processing equipment usually includes optical network terminals (Optical Network Unit, ONU), gateways, routers, switches, mobile phones, computers, servers, tablets, televisions, etc., and information transmission equipment usually includes optical fibers and optical waveguides.

[0027] The optical module can realize the mutual conversion between optical signals and electrical signals between information processing equipment and information transmission equipment. For example, at least one of the optical signal input end or the optical signal output end of the optical module is connected to an optical fiber, and at least one of the electrical signal input end or the electrical signal output end of the optical module is connected to an optical network terminal; the first optical signal from the optical fiber is transmitted to the optical module, and the optical module converts the first optical signal into a first electrical signal, and transmits the first electrical signal to the optical network terminal; the second electrical signal from the optical network terminal is transmitted to the optical module, and the optical module converts the second electrical signal into a second optical signal, and transmits the second optical signal to the optical fiber. Since multiple information processing devices can transmit information through electrical signals, at least one of the multiple information processing devices needs to be directly connected to the optical module, and all information processing devices do not need to be directly connected to the optical module. Here, the information processing device directly connected to the optical module is called the upper computer of the optical module. In addition, the optical signal input end or the optical signal output end of the optical module can be called an optical port, and the electrical signal input end or the electrical signal output end of the optical module can be called an electrical port.

[0028] Figure 1 FIG. 1 is a partial structural diagram of an optical communication system according to some embodiments. Figure 1 As shown, the optical communication system mainly includes a remote information processing device 1000 , a local information processing device 2000 , a host computer 100 , an optical module 200 , an optical fiber 101 and a network cable 103 .

[0029] One end of the optical fiber 101 extends toward the remote information processing device 1000, and the other end of the optical fiber 101 is connected to the optical module 200 through the optical port of the optical module 200. The optical signal can be totally reflected in the optical fiber 101, and the propagation of the optical signal in the total reflection direction can almost maintain the original optical power. The optical signal undergoes multiple total reflections in the optical fiber 101 to transmit the optical signal from the remote information processing device 1000 to the optical module 200, or to transmit the optical signal from the optical module 200 to the remote information processing device 1000, thereby realizing long-distance, low-power loss information transmission.

[0030] The optical communication system may include one or more optical fibers 101, and the optical fibers 101 are detachably connected or fixedly connected to the optical module 200. The host computer 100 is configured to provide data signals to the optical module 200, receive data signals from the optical module 200, or monitor or control the working state of the optical module 200.

[0031] The host computer 100 includes a substantially rectangular housing and an optical module interface 102 disposed on the housing. The optical module interface 102 is configured to connect to the optical module 200 so that the host computer 100 and the optical module 200 establish a unidirectional or bidirectional electrical signal connection.

[0032] The host computer 100 also includes an external electrical interface, which can be connected to an electrical signal network. For example, the external electrical interface includes a Universal Serial Bus (USB) interface or a network cable interface 104, and the network cable interface 104 is configured to access the network cable 103 so that the host computer 100 establishes a unidirectional or bidirectional electrical signal connection with the network cable 103. One end of the network cable 103 is connected to the local information processing device 2000, and the other end of the network cable 103 is connected to the host computer 100, so as to establish an electrical signal connection between the local information processing device 2000 and the host computer 100 through the network cable 103. For example, the third electrical signal sent by the local information processing device 2000 is transmitted to the host computer 100 through the network cable 103, and the host computer 100 generates a second electrical signal according to the third electrical signal. The second electrical signal from the host computer 100 is transmitted to the optical module 200, and the optical module 200 converts the second electrical signal into a second optical signal, and transmits the second optical signal to the optical fiber 101, and the second optical signal is transmitted to the remote information processing device 1000 in the optical fiber 101. For example, the first optical signal from the remote information processing device 1000 is transmitted through the optical fiber 101, and the first optical signal from the optical fiber 101 is transmitted to the optical module 200, and the optical module 200 converts the first optical signal into a first electrical signal, and the optical module 200 transmits the first electrical signal to the host computer 100, and the host computer 100 generates a fourth electrical signal according to the first electrical signal, and transmits the fourth electrical signal to the local information processing device 2000. It should be noted that the optical module is a tool for realizing the mutual conversion between optical signals and electrical signals. During the conversion process between the optical signals and electrical signals, the information does not change, but the encoding and decoding methods of the information can change.

[0033] In addition to the optical network terminal, the host computer 100 also includes an optical line terminal (OLT), an optical network device (ONT), or a data center server.

[0034] Figure 2 FIG. 1 is a partial structural diagram of a host computer according to some embodiments. In order to clearly show the connection relationship between the optical module 200 and the host computer 100, Figure 2 Only the structure of the host computer 100 related to the optical module 200 is shown. Figure 2 As shown, the host computer 100 further includes a PCB circuit board 105 disposed in the housing, a cage 106 disposed on the surface of the PCB circuit board 105, a heat sink 107 disposed on the cage 106, and an electrical connector disposed inside the cage 106. The electrical connector is configured to access the electrical port of the optical module 200; the heat sink 107 has a protruding structure such as fins to increase the heat dissipation area.

[0035] The optical module 200 is inserted into the cage 106 of the host computer 100, and the cage 106 fixes the optical module 200. The heat generated by the optical module 200 is transferred to the cage 106 and then diffused through the heat sink 107. After the optical module 200 is inserted into the cage 106, the electrical port of the optical module 200 is connected to the electrical connector inside the cage 106, so that the optical module 200 establishes a bidirectional electrical signal connection with the host computer 100. In addition, the optical port of the optical module 200 is connected to the optical fiber 101, so that the optical module 200 establishes a bidirectional optical signal connection with the optical fiber 101.

[0036] Figure 3 is a structural diagram of an optical module according to some embodiments, Figure 4 FIG. 1 is an exploded view of an optical module according to some embodiments. Figure 3 and Figure 4 As shown, the optical module 200 includes a shell, a circuit board 300 disposed in the shell, an optical modulation chip 900a, a light source 900b, etc. However, the present disclosure is not limited thereto.

[0037] The housing comprises an upper housing 201 and a lower housing 202 . The upper housing 201 covers the lower housing 202 to form the housing having two openings 204 and 205 . The outer contour of the housing is generally a square body.

[0038] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 located on both sides of the bottom plate 2021 and arranged perpendicular to the bottom plate 2021; the upper shell 201 includes a cover plate 2011, and the cover plate 2011 covers the two lower side plates 2022 of the lower shell 202 to form the above-mentioned shell.

[0039] In some embodiments, the lower shell 202 includes a bottom plate 2021 and two lower side plates 2022 located on both sides of the bottom plate 2021 and vertically arranged with the bottom plate 2021; the upper shell 201 includes a cover plate 2011 and two upper side plates located on both sides of the cover plate 2011 and vertically arranged with the cover plate 2011, and the two upper side plates are combined with the two lower side plates 2022 to realize that the upper shell 201 covers the lower shell 202.

[0040] The direction of the line connecting the two openings 204 and 205 may be consistent with the length direction of the optical module 200, or may be inconsistent with the length direction of the optical module 200. For example, the opening 204 is located at the end of the optical module 200 ( Figure 3 The opening 205 is also located at the end of the optical module 200 ( Figure 3 Alternatively, the opening 204 is located at the end of the optical module 200, and the opening 205 is located at the side of the optical module 200. The opening 204 is an electrical port, and the gold finger 301 of the circuit board 300 extends from the opening 204 and is inserted into the electrical connector of the host computer 100; the opening 205 is an optical port, which is configured to access the external optical fiber 101, so that the optical fiber 101 is connected to the optical modulation chip 900a and the light source 900b in the optical module 200.

[0041] The upper housing 201 and the lower housing 202 are combined to facilitate the installation of the circuit board 300, the optical modulation chip 900a, the light source 900b, etc. into the housing, and the upper housing 201 and the lower housing 202 can encapsulate and protect the above components. In addition, when assembling the circuit board 300, the optical modulation chip 900a, the light source 900b, etc., it is convenient to deploy the positioning components, heat dissipation components, and electromagnetic shielding components of these components, which is conducive to automated production.

[0042] In some embodiments, the upper shell 201 and the lower shell 202 are made of metal materials to facilitate electromagnetic shielding and heat dissipation.

[0043] In some embodiments, the optical module 200 further includes an unlocking component 600 located outside its housing. The unlocking component 600 is configured to achieve a fixed connection between the optical module 200 and the host computer, or to release the fixed connection between the optical module 200 and the host computer.

[0044] For example, the unlocking component 600 is located on the outside of the two lower side plates 2022 of the lower housing 202, and includes a snap-fit ​​component that matches the cage 106 of the host computer 100. When the optical module 200 is inserted into the cage 106, the snap-fit ​​component of the unlocking component 600 fixes the optical module 200 in the cage 106; when the unlocking component 600 is pulled, the snap-fit ​​component of the unlocking component 600 moves accordingly, thereby changing the connection relationship between the snap-fit ​​component and the host computer, so as to release the fixation of the optical module 200 and the host computer, so that the optical module 200 can be pulled out of the cage 106.

[0045] The circuit board 300 includes circuit traces, electronic components and chips, etc. The electronic components and chips are connected according to the circuit design through the circuit traces to realize the functions of power supply, electrical signal transmission and grounding. The electronic components may include capacitors, resistors, transistors, metal-oxide-semiconductor field-effect transistors (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET), etc. The chips may include microcontroller units (Microcontroller Unit, MCU), laser driver chips, transimpedance amplifiers (Transimpedance Amplifier, TIA), limiting amplifiers (Limiting amplifier), clock and data recovery chips (Clock and Data Recovery, CDR), power management chips, digital signal processing (Digital Signal Processing, DSP) chips.

[0046] The circuit board 300 is generally a rigid circuit board. Due to its relatively hard material, the rigid circuit board can also realize the load-bearing function. For example, the rigid circuit board can stably carry the above-mentioned electronic components and chips; the rigid circuit board can also be inserted into the electrical connector in the cage 106 of the host computer 100.

[0047] The circuit board 300 also includes a gold finger 301 formed on the end surface thereof. The gold finger 301 is composed of a plurality of independent pins. The circuit board 300 is inserted into the cage 106, and the gold finger 301 is connected to the electrical connector in the cage 106. The gold finger 301 can be provided on only one side of the circuit board 300 (e.g. Figure 4The upper surface shown in the figure) can also be set on the upper and lower surfaces of the circuit board 300 to provide more pins, so as to adapt to occasions where the number of pins is large. The gold finger 301 is configured to establish an electrical connection with the host computer to achieve power supply, grounding, two-wire synchronous serial (Inter-Integrated Circuit, I2C) signal transmission, data signal transmission, etc. Of course, flexible circuit boards are also used in some optical modules. Flexible circuit boards are generally used in conjunction with rigid circuit boards to supplement rigid circuit boards.

[0048] The optical modulation chip 900a itself does not have a light source, so the light source 900b is selected as an external light source of the optical modulation chip 900a. The light source 900b can be a laser box, in which a laser chip is encapsulated. The laser chip emits light to generate a laser beam. The light source 900b is used to provide the emission laser to the optical modulation chip 900a. The laser has good single wavelength characteristics and better wavelength tuning characteristics and has become the preferred light source for optical modules and even optical fiber transmission. Other types of light, such as LED light, are generally not used in common optical communication systems. Even if such a light source is used in a special optical communication system, the characteristics of the light source and the chip components are greatly different from those of the laser, so that there are great technical differences between the optical module using the laser and the optical module using other light sources. Those skilled in the art generally do not think that these two types of optical modules can give each other technical inspiration.

[0049] The bottom surface of the optical modulator chip 900a and the bottom surface of the light source 900b are respectively arranged on the substrate, and there is an optical connection between the optical modulator chip 900a and the light source 900b. The optical path is very sensitive to the positional relationship between the silicon photonic chip and the light source. Materials with different expansion coefficients will cause different degrees of deformation, which is not conducive to the realization of the preset optical path. In the embodiment of the present application, the optical modulator chip 900a and the light source are arranged on the same substrate. Deformation of the substrate made of the same material will equally affect the position of the optical modulator chip 900a and the light source 900b, avoiding a large change in the relative position of the optical modulator chip 900a and the light source. It is preferred to make the expansion coefficient of the substrate material close to the expansion coefficient of the optical modulator chip 900a and / or the light source material.

[0050] In some embodiments, the optical modulation chip 900a can be in the form of a silicon photonic chip, or a thin film lithium niobate chip, etc. Exemplarily, the optical modulation chip 900a is a thin film lithium niobate chip. The thin film lithium niobate chip includes a substrate and an optical modulation thin film layer located on the surface of the substrate, and the optical modulation thin film layer has an input optical waveguide, a Mach Zehnder Modulator (MZM modulator) and an output optical waveguide. The substrate is a glass substrate, and the optical modulation thin film layer can be a lithium niobate thin film, which is laid on the substrate. The thickness of the lithium niobate thin film is less than 100 μm.

[0051] Thin-film lithium niobate chips are relatively small in size and have relatively high integration precision. Compared with silicon photonic chips, thin-film lithium niobate chips have the advantages of low power consumption and low optical loss. Among them, the optical loss of silicon photonic chips is less than 11.2dB, and the optical loss of thin-film lithium niobate chips is less than 10dB.

[0052] The light source 900b provides the light modulation chip 900a, such as a thin-film lithium niobate chip, with a single wavelength and stable power, and does not carry any signal. The thin-film lithium niobate chip modulates the emitted light to load data into the emitted light.

[0053] In some embodiments, the optical modulation chip 900a, such as a thin-film lithium niobate chip, receives the emitted light from the light source 900b on its side; the modulation of the emitted light and the demodulation of the received light are completed by the thin-film lithium niobate chip, and the surface of the thin-film lithium niobate chip is provided with pads electrically connected to the circuit board wiring; specifically, the circuit board provides the data signal from the host computer to the thin-film lithium niobate chip, and the thin-film lithium niobate chip modulates the data signal into the emitted light, and the received light from the outside is demodulated into an electrical signal by the thin-film lithium niobate chip, and then output to the host computer through the circuit board.

[0054] In some embodiments, the optical modulation chip 900a, such as a thin-film lithium niobate chip, includes an optical modulator. Exemplarily, the optical modulator is a Mach Zehnder Modulator (MZM modulator). The MZM modulator divides the input light into two equal signals that enter the two optical branches of the modulator respectively. The materials used in these two optical branches are electro-optical materials, and their refractive index varies with the size of the externally applied electrical signal. Since the change in the refractive index of the optical branch will cause a change in the signal phase, when the output ends of the two branch signal modulators are combined again, the synthesized optical signal will be an interference signal with varying intensity, which is equivalent to converting the change in the electrical signal into a change in the optical signal, thereby achieving modulation of the light intensity.

[0055] Figure 5 is a diagram of the internal structure of an optical module according to some embodiments; Figure 6 FIG. 4 is a structural diagram of an optical modulation chip according to some embodiments. Figure 5 and Figure 6 As shown, in some embodiments, the optical modulator includes a first beam splitter 900a1, a second beam splitter 900a2, a first interference arm 900a3, a second interference arm 900a4, a phase converter 900a5, and a combiner 900a6.

[0056] The first optical splitter 900a1 is used to split the light not carrying a signal emitted by the light source into modulated light and first monitoring light in different proportions.

[0057] The second beam splitter 900a2 is connected to the first beam splitter 900a1, and is used to split the modulated light into a first beam split and a second beam split in the same proportion.

[0058] The first interference arm 900a3 is connected to the second beam splitter 900a2. A first modulation electrode is disposed on the first interference arm 900a3, and the first split light is transmitted through the first interference arm 900a3.

[0059] The second interference arm 900a4 is connected to the second beam splitter 900a2. A second modulation electrode is disposed on the second interference arm 900a4, and the second beam splitting is transmitted through the second interference arm 900a4.

[0060] The first modulation electrode changes the refractive index of the modulator material by electro-optical induction, converts the modulated electrical signal output by the circuit board 300 into a modulated optical signal, and converts the DC optical signal on the first interference arm that does not carry data, i.e., the first split light, into a first alternating optical signal that carries data by using the modulated optical signal; the second modulation electrode changes the refractive index of the modulator material by electro-optical induction, converts the modulated electrical signal output by the circuit board 300 into a modulated optical signal, and converts the DC optical signal on the second interference arm that does not carry data, i.e., the second split light, into a second alternating optical signal that carries data by using the modulated optical signal; the first alternating optical signal and the second alternating optical signal have different phases. The other end of the first interference arm is connected to the first input end of the combiner 900a6, and the other end of the second interference arm is connected to the second input end of the combiner 900a6. The combiner 900a6 combines the first alternating optical signal and the second alternating optical signal into a beam of transmitted light and a beam of second monitoring light by optical processing, thereby realizing the loading of information into the light to form an optical signal carrying information, and completing the modulation process of the transmitted light. The emitted light is output through an optical modulation chip, such as an output optical port of a thin-film lithium niobate chip, while the second monitoring light is output without passing through an optical modulation chip, such as an output optical port of a thin-film lithium niobate chip.

[0061] Under the bias voltage output by the MCU, the phase converter 900a5 adjusts the phase difference of the light output by the first modulation electrode and the second modulation electrode by π / 2. At this time, the optical modulation chip, such as the thin-film lithium niobate chip, is in the optimal working point state. Affected by the change in the working temperature of the modulator, the working point of the optical modulation chip is prone to drift, so that the optical modulation chip is not in the optimal working point state. To this end, the working point of the optical modulation chip needs to be locked at the optimal working point.

[0062] In some embodiments, the optical power is detected by an optical power detector, such as a backlight detector, to determine the working point state of the optical modulation chip. Exemplarily, the backlight detector can be a monitor photodiode (MPD). MPD is a silicon-based detector, and MPD can be directly integrated into a silicon photonic chip. Exemplarily, a silicon-based detector is grown inside the silicon photonic chip. However, when the optical modulation chip uses a thin-film lithium niobate chip with relatively low optical loss, since the MPD is silicon-based, the MPD cannot be integrated inside the thin-film lithium niobate chip, and the MPD needs to be set outside the thin-film lithium niobate chip. Exemplarily, the MPD is attached to the outside of the thin-film lithium niobate chip by optical glue.

[0063] In some embodiments, a first optical power detection component 900c is provided outside the thin-film lithium niobate chip, illustratively, on the light input side of the optical modulator. The first optical power detection component 900c is connected to the optical port outputting the first monitoring light to detect the optical power of the first monitoring light.

[0064] In some embodiments, a second optical power detection component 900d is provided outside the thin-film lithium niobate chip, illustratively, on the light output side of the optical modulator. The second optical power detection component 900d is connected to the optical port outputting the second monitoring light to monitor the optical power of the second monitoring light.

[0065] Figure 7 FIG. 4 is a structural diagram of a first optical power detection component according to some embodiments. Figure 7 As shown, in some embodiments, the first optical power detection component 900c includes a first optical power detector (such as a first MPD 900c1) and a first resistor 900c2; one end of the first MPD 900c1 is electrically connected to a reference voltage, and the other end is electrically connected to one end of the first resistor 900c2, and the other end of the first resistor 900c2 is grounded. The first MPD 900c1 has a certain responsiveness, converts the detected optical signal into a response current, and converts the response current into a first detection voltage through the first resistor 900c2. Since the first MPD 900c1 is fixed by optical adhesive, due to a certain error in the position of the patch, the responsiveness of the first MPD 900c1 fluctuates within a certain range, so that the value of the first detection voltage also fluctuates within a certain range.

[0066] Figure 8 FIG. 4 is a structural diagram of a second optical power detection component according to some embodiments. Figure 8As shown, in some embodiments, the second optical power detection component 900d includes a second optical power detector (such as a second MPD 900d1) and a second resistor 900d2; one end of the second MPD 900d1 is electrically connected to a reference voltage, and the other end is electrically connected to one end of the second resistor 900d2, and the other end of the second resistor 900d2 is grounded. The second MPD 900d1 has a certain responsiveness, converts the detected optical signal into a response current, and converts the response current into a second detection voltage through the second resistor 900d2. Since the second MPD 900d1 is fixed by optical adhesive, due to a certain error in the position of the patch, the responsiveness of the second MPD 900d1 fluctuates within a certain range, so that the value of the second detection voltage also fluctuates within a certain range.

[0067] Fig. 9 FIG. 4 is a structural diagram of a comparison circuit according to some embodiments. Fig. 9 As shown, in some embodiments, the optical module further includes a comparison circuit 900e. The comparison circuit 900e includes a first input terminal, a second input terminal and an output terminal. The first input terminal is electrically connected to the output terminal of the second optical power detection component 900d to receive the second detection voltage. The second input terminal is electrically connected to the output terminal of the first optical power detection component 900c to receive the first detection voltage. Exemplarily, the comparison circuit 900e is an operational amplifier, whose first input terminal is a negative input terminal and the second input terminal is a positive input terminal.

[0068] The comparison circuit 900e outputs a comparison voltage according to the first detection voltage and the second detection voltage, and the comparison voltage can be monitored by the MCU as an output voltage. Exemplarily, the comparison voltage is related to the difference between the first detection voltage and the second detection voltage. In some embodiments, when the optical module is in a preset state, exemplarily, the preset state includes: the optical modulator chip 900a, such as the optical modulator of the thin film lithium niobate chip, is in the state of the optimal working point, and the comparison voltage at this time is used as the preset voltage. When the value of the comparison voltage is monitored to be unequal to the value of the preset voltage, it means that the optical modulator of the thin film lithium niobate chip is not in the state of the optimal working point at this time. At this time, the MCU adjusts the bias voltage provided to the phase converter 900a5, thereby adjusting the refractive index of one of the interference arms, thereby changing the value of the second detection voltage, and adjusting the difference between the first detection voltage and the second detection voltage to the preset difference, so that the comparison voltage reaches the preset voltage, so that the optical modulator of the thin film lithium niobate chip is in the state of the optimal working point. Exemplarily, the preset difference corresponds to the preset voltage.

[0069] Fig.10 FIG. 1 is a schematic diagram of interaction between an MCU and a phase converter according to some embodiments. Fig.10As shown, by adjusting the bias voltage provided to the phase converter 900a5, the difference between the first detection voltage and the second detection voltage is adjusted to a preset difference, and then the comparison voltage is adjusted to a preset voltage, and the operating point of the optical modulator is adjusted to an optimal operating point, thereby achieving continuous feedback control.

[0070] The comparison voltage can only be monitored by the MCU when it is a non-negative voltage. However, since the first MPD 900c1 and the second MPD 900d1 are external, the patch position is random within a certain range, so the size relationship between the first detection voltage and the second detection voltage cannot be guaranteed. The difference between the first detection voltage and the second detection voltage of the optical module may be positive or negative; for different optical modules, the positive and negative difference between the first detection voltage and the second detection voltage is different, that is, for different optical modules, the difference between the first detection voltage and the second detection voltage is uncertain. Exemplarily, for the first optical module, the difference between the first detection voltage and the second detection voltage may be a positive value; for the second optical module, the difference between the first detection voltage and the second detection voltage may be a negative value, which cannot be detected by the MCU; for the third optical module, the difference between the first detection voltage and the second detection voltage may also be a negative value, which cannot be detected by the MCU.

[0071] In some embodiments, when the difference between the first detection voltage and the second detection voltage is a negative value, it cannot be detected by the MCU, and the first resistor 900c2 or the second resistor 900d2 is replaced to adjust the resistance of the first resistor or the second resistor so that the difference between the first detection voltage and the second detection voltage is a non-negative value. However, replacing the resistor will inevitably increase the production cost, and when the production volume is large, there will be many optical modules with a negative difference between the first detection voltage and the second detection voltage, which will increase the workload and reduce the work efficiency.

[0072] In some embodiments, the first resistor 900c2 and the second resistor 900d2 are kept unchanged, and a compensation voltage is provided to the comparison circuit 900e through the MCU; illustratively, the MCU output terminal is electrically connected to the second input terminal of the comparison circuit 900e to output the compensation voltage to the comparison circuit 900e. The compensation voltage can compensate for the voltage deviation caused by the patch, thereby ensuring that the comparison voltage is a non-negative voltage, so that it can be monitored by the MCU. The second input terminal of the comparison circuit 900e simultaneously receives the first detection voltage and the compensation voltage, thereby increasing the input voltage of the positive input terminal of the comparison circuit 900e, so that the input voltage of the positive input terminal is greater than the input voltage of the negative input terminal, so as to ensure that the comparison voltage output by the comparison circuit 900e is a non-negative voltage.

[0073] In some embodiments, when the optical module is in a preset state, if the comparison voltage cannot be monitored, a first compensation voltage is input to the comparison circuit 900e, and the second input terminal of the comparison circuit 900e simultaneously receives the first detection voltage and the first compensation voltage, thereby increasing the input voltage of the positive input terminal of the comparison circuit 900e, so that the input voltage of the positive input terminal is greater than the input voltage of the negative input terminal, so as to ensure that the comparison voltage output by the comparison circuit 900e is a non-negative voltage.

[0074] In some embodiments, when the optical module is in a preset state, if the comparison voltage is monitored, the second compensation voltage is input to the comparison circuit 900e. Exemplarily, the second compensation voltage is 0 V. That is, when the optical module is in a preset state, if the comparison voltage is monitored, the compensation voltage is not input to the comparison circuit 900e.

[0075] Exemplarily, when the optical module is in a preset state, if the MCU monitors that the comparison voltage is 0V, it either means that the comparison voltage is not monitored, or that the comparison voltage output by the comparison circuit 900e is 0V. For the convenience of control, when the optical module is in a preset state, if the MCU monitors that the comparison voltage is 0V, the compensation voltage is uniformly input to the comparison circuit 900e, and the compensation voltage is gradually increased until the comparison voltage output by the comparison circuit 900e reaches the preset voltage.

[0076] In some embodiments, if the bias voltage provided to the phase converter 900a5 is adjusted so that the difference between the first detection voltage and the second detection voltage is non-negative, and the bias voltage provided to the phase converter 900a5 is adjusted without limit, although the difference can be guaranteed to be non-negative, it is possible that the operating point of the optical modulator in the optical modulation chip is no longer at the optimal operating point.

[0077] For different optical modules, the preset voltage corresponding to the comparison circuit 900e may be the same fixed value or different fixed values. For example, the preset voltage corresponding to the comparison circuit 900e is the same fixed value, recorded as V 预设 For any optical module, when the optical module is in a preset state, if the MCU monitors that the comparison voltage is 0V, the compensation voltage is input to the comparison circuit 900e, and the compensation voltage is gradually increased until the comparison voltage output by the comparison circuit 900e reaches the preset voltage V 预设 until.

[0078] For different optical modules, the compensation voltage input by the MCU to the comparison circuit 900e may be different values. For example, the preset voltage of the first optical module is V 预设 , the compensation voltage is V Q1 ; The preset voltage of the second optical module is V 预设 , the compensation voltage is V Q2The preset voltage of the third optical module is Vout, and the compensation voltage is V Q3 ; The preset voltage of the fourth optical module is V 预设 , the compensation voltage is V Q4 ….

[0079] In some embodiments of the present disclosure, under the premise of keeping the hardware structure unchanged, a compensation voltage is provided to the comparison circuit through the MCU, thereby avoiding the need to replace the resistor, and the comparison voltage is monitored by the MCU from the software perspective. At the same time, the compensation voltage participates in the locking of the working point, which can reduce production costs and improve production efficiency.

[0080] For an optical module, when it is in a preset state, if the MCU monitors that the comparison voltage is 0V, the compensation voltage is input to the comparison circuit 900e, and the compensation voltage is gradually increased until the comparison voltage output by the comparison circuit 900e reaches the preset voltage V 预设 At this time, the compensation voltage is V Q In order to facilitate the locking of the operating point, the compensation voltage V Q Will maintain continuous and constant output; when the operating point drifts, the compensation voltage V Q Under the action, the MCU then adjusts the bias voltage provided to the phase converter 900a5 so that the difference between the first detection voltage and the second detection voltage reaches the preset difference. At this time, the comparison voltage reaches the preset voltage V 预设 , the corresponding working point is the optimal working point.

[0081] In some embodiments, a third resistor R3 is provided between the output terminal of the second optical power detection component 900d and the first input terminal of the comparison circuit 900e. The third resistor R3 is a current limiting resistor. The third resistor R3 reduces the power consumption control voltage and plays a role of safety protection.

[0082] In some embodiments, a fourth resistor R4 is provided between the output end of the first optical power detection component 900c and the second input end of the comparison circuit 900e, and the fourth resistor R4 is a current limiting resistor; the fourth resistor R4 is connected in parallel with the third resistor R3. The fourth resistor R4 reduces the power consumption control voltage on the one hand, and plays a role of safety protection on the other hand.

[0083] In some embodiments, a fifth resistor R5 is provided between the MCU output terminal and the second input terminal of the comparison circuit 900e, and the fifth resistor R5 is a current limiting resistor; the fifth resistor R5, the fourth resistor R4, and the third resistor R3 are connected in parallel. The fifth resistor R5 reduces the power consumption control voltage on the one hand, and plays a role of safety protection on the other hand.

[0084] In some embodiments, a sixth resistor R6 is provided between the first input terminal of the comparison circuit 900e and the output terminal of the comparison circuit 900e; the sixth resistor R6 is connected in parallel with the third resistor R3. The sixth resistor R6 plays a role in amplifying the output voltage.

[0085] In some embodiments, a seventh resistor R7 is provided in parallel with the fifth resistor R5 , one end of the seventh resistor R7 is electrically connected to the second input end of the comparison circuit 900 e , and the other end of the seventh resistor R7 is grounded.

[0086] In some embodiments, the comparison circuit 900e obtains and outputs a comparison voltage according to the first detection voltage, the second detection voltage, and the compensation voltage.

[0087] Exemplarily, according to the first resistor, the second resistor, the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6, Vout=[(R P *R 3 +R 6 *R P ) / (R 3 *R 4 )]*V MPD1 +[(R 3 *R P +R 6 *R P ) / (R 3 *R 5 )]*V Q -R 6 / R 3 *V MPD2 ;

[0088] Wherein, Vout is the output voltage of the comparison circuit 900e; R P =R 4 / / R 5 / / R 7 ; V MPD1 is the first detection voltage, V MPD1 The value is equal to the response current detected by the first MPD * the first resistor; V MPD2 is the second detection voltage, V MPD2 The value is equal to the response current detected by the second MPD * the second resistor; V Q It is the compensation voltage input by MCU to the comparison circuit 900e.

[0089] By adjusting the resistance, the following conditions are met between the resistors: R3 / / R6=R4 / / R5 / / R7, R 3 =R 4 =R 5 =R, then Vout = R 6 (V MPD1 / R+VQ / RV MPD2 / R); It can be seen that the comparison voltage Vout output by the comparison circuit 900e is equal to the first detection voltage V MPD1 , the second detection voltage V MPD2 , compensation voltage V Q Keep the output fixed compensation voltage V Q , the first detection voltage V MPD1 , the second detection voltage V MPD2 The difference between them is adjusted to a preset difference, and the comparison voltage Vout can reach the preset voltage V 预设 , thereby adjusting the operating point of the optical modulator in the optical modulation chip to the optimal operating point. Exemplarily, the output fixed compensation voltage V Q , the first detection voltage V MPD1 , the second detection voltage V MPD2 When the difference between them is a preset difference, the comparison voltage Vout can reach the preset voltage. At this time, the corresponding working state of the optical modulation chip is at the optimal working point.

[0090] In some embodiments, the output constant compensation voltage is maintained. When the comparison voltage Vout output by the comparison circuit 900e is not the preset voltage, it indicates that the working state corresponding to the optical modulator in the optical modulation chip is not the optimal working point. Then, the first detection voltage V MPD1 , the second detection voltage V MPD2 The difference between them is adjusted to a preset difference, thereby adjusting the comparison voltage to a preset voltage, and adjusting the operating point of the optical modulator to an optimal operating point.

[0091] In some embodiments, the preset voltage corresponding to the comparison voltage corresponding to each optical module is uniformly set to V 预设 .

[0092] In some embodiments, at room temperature, by adjusting the bias voltage provided to the phase converter 900a5, the output optical power is half of the maximum optical power, and the optical modulation chip works at the optimal working point; if the comparison voltage output by the comparison circuit 900e is monitored to be 0V, the compensation voltage is gradually input to the comparison circuit 900e, and the compensation voltage is gradually increased until the comparison voltage output by the comparison circuit 900e reaches the preset voltage V 预设 Until; record the compensation voltage V at this time Q Then the compensation voltage V is continuously and constantly output. Q Since the working state of the optical modulation chip is the optimal working point at this time, the corresponding output compensation voltage V Q , to ensure that the comparison voltage Vout reaches the preset voltage V 预设, so the compensation voltage V should be output continuously and constantly Q , can ensure that when the comparison voltage Vout reaches the preset voltage V 预设 At this time, the working state of the optical modulation chip is at the optimal working point. At high or low temperatures, the output compensation voltage V is kept fixed. Q , when the comparison voltage Vout output by the comparison circuit 900e is not the preset voltage V 预设 , indicating that the working state of the optical modulation chip is not the optimal working point, then the first detection voltage V MPD1 , the second detection voltage V MPD2 The difference between them is adjusted to a preset difference, and then the comparison voltage is adjusted to a preset voltage V 预设 , adjust the operating point of the optical modulator to the optimal operating point.

[0093] In some embodiments of the present application, for the same optical module, the compensation voltage V is continuously and constantly output in all temperature zones. Q Then, when the comparison voltage output by the comparison circuit 900e is not the preset voltage, it means that the working state corresponding to the optical modulation chip is not the optimal working point. Then, the first detection voltage V MPD1 , the second detection voltage V MPD2 The difference between them is adjusted to a preset difference, and then the comparison voltage is adjusted to a preset voltage V 预设 , adjust the working point of the optical modulator to the optimal working point, thereby achieving continuous feedback control. For example, for the same optical module, the compensation voltage V in different temperature zones is Q Is a fixed value.

[0094] In some embodiments of the present application, for different optical modules, the compensation voltage V Q For different voltage values, the preset voltage V 预设 are the same voltage value.

[0095] In the present application, due to the properties of the thin-film lithium niobate chip, the first MPD 900c1 and the second MPD 900d1 are externally placed on the thin-film lithium niobate chip, and the chip positions are random within a certain range. Therefore, the size relationship between the first detection voltage and the second detection voltage cannot be guaranteed. The difference between the first detection voltage and the second detection voltage of the optical module may be positive or negative. On the premise of keeping the hardware structure unchanged, the compensation voltage is provided to the comparison circuit through the MCU, and the comparison voltage is monitored by the MCU from the software perspective, thereby saving production costs and improving production efficiency.

[0096] In the present application, for the same optical module, the compensation voltage is continuously and constantly outputted in different temperature zones, and the first detection voltage V is adjusted by adjusting the bias voltage provided to the phase converter. MPD1 , the second detection voltage V MPD2 The difference between them is adjusted to a preset difference, thereby adjusting the comparison voltage to a preset voltage, and adjusting the operating point of the optical modulator to an optimal operating point, thereby achieving continuous feedback control.

[0097] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be thought of by any person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. An optical module, It is 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 signal; An optical modulation chip, electrically connected to the circuit board, comprising an optical modulator, wherein the optical modulation chip is used to modulate the light not carrying a signal into a signal light; wherein the optical modulator comprises a phase converter; A first optical power detection component is arranged outside the optical modulation chip and on the light input side of the optical modulator; A second optical power detection component is arranged outside the optical modulation chip and on the light output side of the optical modulator. When the difference between the first detection voltage and the second detection voltage is a preset difference, the optical module is in a preset state, and the positive and negative values ​​of the difference corresponding to different optical modules are different; wherein the first detection voltage is the detection voltage of the first optical power detection component, and the second detection voltage is the detection voltage of the second optical power detection component; A comparison circuit, wherein the first input terminal receives the second detection voltage, and the second input terminal receives the first detection voltage and the compensation voltage output by the MCU; the comparison circuit is used to output a comparison voltage according to the first detection voltage, the second detection voltage and the compensation voltage; when the comparison voltage is a preset voltage, the optical module is in a preset state; when the comparison voltage is a negative voltage, it cannot be monitored; The MCU is electrically connected to the circuit board and is configured to input the compensation voltage to the comparison circuit when the optical module is in a preset state so that the comparison voltage is a non-negative voltage while maintaining the output of the compensation voltage; and when monitoring that the comparison voltage is not a preset voltage, adjust the bias voltage provided to the phase converter so that the difference between the first detection voltage and the second detection voltage is a preset difference, thereby adjusting the comparison voltage to the preset voltage.

2. The optical module according to claim 1, It is characterized in that The MCU is configured as: When the optical module is in a preset state, if the comparison voltage cannot be monitored, a first compensation voltage is input to the comparison circuit to make the comparison voltage a non-negative voltage.

3. The optical module according to claim 1, It is characterized in that The MCU is configured as: When the optical module is in a preset state, if the comparison voltage is monitored, a second compensation voltage is input to the comparison circuit.

4. The optical module according to claim 1, It is characterized in that The optical modulation chip further includes: A first optical splitter, used for splitting the light not carrying a signal emitted by the light source into modulated light and first monitoring light in different proportions, wherein an optical port outputting the first monitoring light is connected to the first optical power detection component; A second beam splitter, connected to the first beam splitter, for splitting the modulated light into a first beam split and a second beam split in the same proportion; A first interference arm, connected to the second beam splitter, for transmitting the first beam split; A second interference arm, connected to the second beam splitter, for transmitting the second beam split; A combiner is used to combine the first split light and the second split light and couple them into emission light and second monitoring light, wherein the optical port for outputting the second monitoring light is connected to the second optical power detection component.

5. The optical module according to claim 1, It is characterized in that The first optical power detection component includes a first optical power detector and a first resistor; one end of the first optical power detector is electrically connected to a reference voltage, the other end is electrically connected to one end of the first resistor, and the other end of the first resistor is grounded; The second optical power detection component includes a second optical power detector and a second resistor; one end of the first optical power detector is electrically connected to a reference voltage, and the other end is electrically connected to one end of the second resistor, and the other end of the second resistor is grounded.

6. The optical module according to claim 1, It is characterized in that A third resistor is provided between the output end of the second optical power detection component and the first input end of the comparison circuit, and the third resistor is a current limiting resistor.

7. The optical module according to claim 6, It is characterized in that A fourth resistor is provided between the output end of the first optical power detection component and the second input end of the comparison circuit, and the fourth resistor is a current limiting resistor; the fourth resistor is connected in parallel with the third resistor.

8. The optical module according to claim 7, It is characterized in that A fifth resistor is provided between the MCU output terminal and the second input terminal of the comparison circuit, and the fifth resistor is a current limiting resistor; the fifth resistor, the fourth resistor, and the third resistor are respectively connected in parallel.

9. The optical module according to claim 8, It is characterized in that A sixth resistor is provided between the first input terminal of the comparison circuit and the output terminal of the comparison circuit; the sixth resistor is connected in parallel with the third resistor.

10. The optical module according to claim 1, It is characterized in that When the optical module is in the preset state, the optical modulator is at an optimal working point.

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