A wavelength division multiplexed optical interconnection system

Abstract

The application discloses a kind of wavelength division multiplexing optical interconnection systems, comprising: multi-wavelength light source, for generating and outputting multi-wavelength continuous wave laser, multi-wavelength continuous wave laser contains the laser of multiple wavelengths with preset wavelength interval;Transmitter, for receiving multi-wavelength continuous wave laser, and each wavelength laser in multi-wavelength continuous wave laser is loaded with data to generate multi-wavelength optical signal, and each wavelength optical signal is added with unique pilot label;Receiver, for receiving multi-wavelength optical signal, and according to the pilot label carried by each wavelength optical signal, the optical signal of target wavelength is identified, and the data in the optical signal of target wavelength is locked and demodulated. Precise identification and locking of the working wavelength of micro-ring filter are realized, the problems of channel identification difficulty and wrong wavelength locking in micro-ring wavelength division multiplexing system are solved, and the stability and reliability of the overall interconnection system are improved.

Description

Technical Field

[0001] This application relates to the field of optical interconnects, and in particular to a wavelength division multiplexing optical interconnect system. Background Technology

[0002] With the rapid development of artificial intelligence and data center applications, large-scale model training and high-performance computing place higher demands on data exchange capacity, driving the interconnect architecture within data centers towards higher bandwidth density and lower power consumption. Silicon-based photonics-based microring modulator wavelength division multiplexing (WDM) technology, with its advantages of small size, low power consumption, and wavelength selectivity, has become an important solution for achieving high-density optical interconnects. However, the resonant characteristics of microrings are extremely sensitive to environmental temperature fluctuations. In dense WDM systems, the spacing between adjacent wavelengths is extremely small. When the operating temperature changes drastically, the microring is prone to locking onto adjacent incorrect channels, leading to logical link chaos and affecting communication efficiency.

[0003] Therefore, how to provide a solution to the above-mentioned technical problems is a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0004] The purpose of this application is to provide a wavelength division multiplexing optical interconnect system that achieves accurate identification and locking of the operating wavelength of the micro-ring filter, solves the problems of difficult channel identification and incorrect wavelength locking in the micro-ring wavelength division multiplexing system, and improves the stability and reliability of the overall interconnect system.

[0005] To address the aforementioned technical problems, this application provides a wavelength division multiplexing optical interconnect system, comprising: A multi-wavelength light source is used to generate and output multi-wavelength continuous wave laser, wherein the multi-wavelength continuous wave laser comprises multiple lasers with preset wavelength intervals. A transmitter is used to receive the multi-wavelength continuous wave laser, load data onto each wavelength of the multi-wavelength continuous wave laser to generate multi-wavelength optical signals, and add a unique pilot label to each wavelength of the optical signal. A receiver is used to receive the multi-wavelength optical signals, identify the target wavelength optical signal based on the pilot tags carried by each wavelength optical signal, and lock and demodulate the data in the target wavelength optical signal.

[0006] Optionally, the transmitter includes multiple sub-transmitting modules, each sub-transmitting module corresponding to a multiple wavelength. Each sub-transmitting module is used to receive the multi-wavelength continuous wave laser, extract the laser corresponding to the target wavelength from the multi-wavelength continuous wave laser, load data onto the laser to generate an optical signal, and add a unique pilot tag to the optical signal.

[0007] Optionally, each of the sub-transmission modules includes: A micro-ring modulator is used to couple out laser light of its own target wavelength from the multi-wavelength continuous wave laser, and modulate the coupled laser light according to the received data signal to output an optical signal carrying data. A first heater is provided corresponding to the micro-ring modulator and is used to adjust the operating wavelength of the micro-ring modulator. A pilot injection unit, connected to the first heater, is used to superimpose a low-frequency pilot signal onto the heating voltage signal of the first heater, so that the optical signal output by the micro-ring modulator carries a pilot tag; The frequency of the low-frequency pilot signal corresponding to the pilot injection unit of each of the sub-transmitting modules is unique.

[0008] Optionally, each of the sub-transmitting modules further includes: The first photodetector is used to convert the optical signal at the download end of the micro-ring modulator into a first current signal; A first control circuit is used to adjust the heating power of the first heater according to the first current signal, so as to lock the operating wavelength of the micro-ring modulator at the target wavelength.

[0009] Optionally, the first control circuit includes: A first transimpedance amplifier is used to convert the first current signal into a voltage signal and amplify it; The first analog-to-digital converter is used to convert the amplified voltage signal from analog to digital to obtain a digital signal. A microcontroller is configured to generate a first power control signal based on the digital signal to adjust the heating power of the first heater.

[0010] Optionally, the receiver includes multiple sub-receiving modules, each of which corresponds one-to-one with a multiple pilot tags. Each sub-receiving module is used to identify and lock the optical signal of the target wavelength according to the corresponding pilot tag, and demodulate data from the locked optical signal of the target wavelength.

[0011] Optionally, each of the sub-receiving modules includes: A micro-ring filter is used to download an optical signal corresponding to the target wavelength from the multi-wavelength optical signal; The second heater is configured corresponding to the micro-ring filter and is used to adjust the operating wavelength of the micro-ring filter. The second photodetector is used to convert the optical signal at the download end of the micro-ring filter into a second current signal; A pilot demodulator, connected to the second photodetector, is used to demodulate the corresponding pilot tag from the second current signal; The second control circuit is used to adjust the heating power of the second heater according to the demodulated pilot tag, so as to lock the operating wavelength of the micro-ring filter to the target wavelength.

[0012] Optionally, the second control circuit includes: A second transimpedance amplifier is used to convert the second current signal into a first voltage signal; A second analog-to-digital converter is used to convert the first voltage signal into a digital signal; A logic controller is configured to generate a second power control signal based on the digital signal and the pilot tag demodulated by the pilot demodulator; A second digital-to-analog converter is used to convert the second power control signal into an analog heating voltage to adjust the heating power of the second heater.

[0013] Optionally, each of the sub-receiving modules further includes: A third transimpedance amplifier is used to convert the second current signal into a second voltage signal; A data receiving circuit is used to demodulate data from the second voltage signal.

[0014] Optionally, each of the sub-receiving modules includes: A cascaded multi-micro-ring filter, and a plurality of second heaters configured in a one-to-one correspondence with the cascaded multi-micro-ring filter; The second photodetector is used to convert the optical signal at the download end of the last micro-ring filter of the cascaded multi-micro-ring filter into a second current signal. A pilot demodulator, connected to the second photodetector, is used to demodulate the corresponding pilot tag from the second current signal; The second control circuit is used to adjust the heating power of multiple second heaters according to the demodulated pilot tags, so as to lock the operating wavelength of the cascaded multi-micro-ring filter to the target wavelength.

[0015] This application provides a wavelength division multiplexing (WDM) optical interconnect system. At the transmitter side, while loading data onto lasers of each wavelength, a unique pilot tag is added to the optical signal of each wavelength. At the receiver side, the target wavelength is identified based on the pilot tag carried by the optical signal, thereby locking and demodulating the data. This application adds an identifiable identifier to each wavelength, enabling the receiver to accurately distinguish different wavelength channels in the frequency domain. Even if changes in ambient temperature cause the micro-ring resonant wavelength to drift, the system can still lock onto the correct target wavelength based on the pilot signal, effectively avoiding the risk of locking onto an adjacent incorrect channel. This achieves accurate identification and locking of the operating wavelength of the micro-ring filter, solving the problems of difficult channel identification and incorrect wavelength locking in micro-ring WDM systems, and improving the stability and reliability of the overall interconnect system. Simultaneously, because each wavelength has an independent identifier, the locking difficulties caused by thermal coupling and signal crosstalk between multiple channels are effectively alleviated, improving the system's scalability and enabling parallel transmission of more wavelength channels. Attached Figure Description

[0016] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a wavelength division multiplexing optical interconnect system provided in an embodiment of this application; Figure 2 This is a schematic diagram of another wavelength division multiplexing optical interconnect system provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of a transmitter provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of a receiver provided in an embodiment of this application; Figure 5 This is a schematic diagram of the structure of a sub-receiving module provided in an embodiment of this application; Figure 6 This is a schematic diagram of another sub-receiving module provided in an embodiment of this application. Detailed Implementation

[0018] The core of this application is to provide a wavelength division multiplexing optical interconnect system that achieves accurate identification and locking of the operating wavelength of the micro-ring filter, solves the problems of difficult channel identification and incorrect wavelength locking in the micro-ring wavelength division multiplexing system, and improves the stability and reliability of the overall interconnect system.

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] Please refer to Figure 1 This application provides a wavelength division multiplexing optical interconnect system, including: A multi-wavelength light source is used to generate and output multi-wavelength continuous wave lasers, which contain multiple lasers with preset wavelength intervals. The transmitter is used to receive multi-wavelength continuous wave lasers, load data onto each wavelength of the multi-wavelength continuous wave laser to generate multi-wavelength optical signals, and add a unique pilot label to each wavelength of the optical signal. The receiver is used to receive multi-wavelength optical signals, identify the target wavelength optical signal based on the pilot tags carried by each wavelength optical signal, and lock and demodulate the data in the target wavelength optical signal.

[0021] In this embodiment, a multi-wavelength light source generates and outputs multi-wavelength continuous-wave laser light, which contains multiple wavelengths with a preset interval between each wavelength. After receiving the multi-wavelength continuous-wave laser light, the transmitter loads data onto each wavelength to generate multi-wavelength optical signals, and simultaneously adds a unique pilot tag to each wavelength's optical signal. Specifically, the transmitter internally processes each wavelength of laser light independently, using a modulation function to load external electrical signal data onto the corresponding wavelength's laser light to form a data-carrying optical signal. A tiny low-frequency signal is added to each optical signal using a pilot tag addition function, forming a unique pilot tag for that wavelength. Different wavelengths of optical signals carry pilot tags of different frequencies. Multi-channel data can be transmitted in parallel, improving communication capacity. It can be understood that the pilot tag serves as an identifier for each wavelength's optical signal, allowing the receiver to distinguish between different channels.

[0022] After receiving multi-wavelength optical signals, the receiver identifies the target wavelength based on the pilot tags carried by each wavelength, locks onto that signal, and demodulates the data. Specifically, the receiver has wavelength selection and demodulation functions. A tunable filter unit selects a specific wavelength from the multi-wavelength optical signals, while a pilot detection function identifies the pilot tags carried in the optical signals. When a target pilot frequency is detected, the receiver locks the filter unit at the corresponding wavelength and demodulates the data from the optical signal at the receiving end. The receiver distinguishes different wavelength channels in the frequency domain based on the pilot tags. Even if changes in ambient temperature cause wavelength drift, it can still lock onto the correct target wavelength based on the pilot signal, avoiding locking onto adjacent incorrect channels.

[0023] As can be seen, this application adds a unique pilot tag to the optical signal of each wavelength while loading data for each wavelength of laser at the transmitter side. At the receiver side, the target wavelength is identified based on the pilot tag carried by the optical signal, thereby locking and demodulating the data. This application adds an identifiable identifier to each wavelength, enabling the receiver to accurately distinguish different wavelength channels in the frequency domain. Even if changes in ambient temperature cause the micro-ring resonant wavelength to drift, the system can still lock the correct target wavelength based on the pilot signal, effectively avoiding the risk of locking to an adjacent incorrect channel. Thus, accurate identification and locking of the operating wavelength of the micro-ring filter is achieved, solving the problems of difficult channel identification and incorrect wavelength locking in micro-ring wavelength division multiplexing systems, and improving the stability and reliability of the overall interconnection system. At the same time, since each wavelength has an independent identifier, the locking difficulties caused by thermal coupling and signal crosstalk between multiple channels are effectively alleviated, the scalability of the system is improved, and it can support the parallel transmission of more wavelength channels.

[0024] Based on the above embodiments: In one exemplary embodiment, please refer to Figure 2 The transmitter includes multiple sub-transmitting modules, each corresponding to a different wavelength. Each sub-transmitting module is used to receive multi-wavelength continuous wave lasers, extract the laser corresponding to the target wavelength from the multi-wavelength continuous wave lasers, load data onto the laser to generate an optical signal, and add a unique pilot tag to the optical signal.

[0025] Based on the above system, the transmitter includes multiple sub-transmission modules, each corresponding one-to-one with a multi-wavelength light source outputting multiple wavelengths. Each sub-transmission module receives multi-wavelength continuous wave laser, extracts the laser corresponding to the target wavelength, loads data onto the laser to generate an optical signal, and adds a unique pilot label to the optical signal.

[0026] A multi-wavelength continuous-wave laser enters a bus waveguide and passes sequentially through each sub-transmitter module. Each sub-transmitter module has a wavelength selection function, capable of coupling out a specific wavelength of laser light from the bus waveguide. As the multi-wavelength continuous-wave laser passes through the bus waveguide, each sub-transmitter module extracts only the wavelength of laser light it is responsible for, while other wavelengths continue to propagate forward. Each sub-transmitter module loads data and adds pilot tags to the extracted laser light, generating an optical signal carrying the data and a unique pilot tag. The optical signals output from all sub-transmitter modules are finally combined into a single multi-wavelength optical signal for output.

[0027] Since multiple sub-transmitter modules correspond one-to-one with multiple wavelengths, multi-wavelength signals can be processed in parallel and independently. Each module is only responsible for a specific wavelength, and the modules do not interfere with each other. This modular structure facilitates system expansion. When increasing the number of wavelength channels, only the corresponding number of sub-transmitter modules need to be added.

[0028] In one exemplary embodiment, such as Figure 3 As shown, each sub-transmission module includes: A micro-ring modulator is used to couple out laser light of its own target wavelength from multi-wavelength continuous wave laser light, and modulate the coupled laser light according to the received data signal to output an optical signal carrying data. The first heater is set up in correspondence with the micro-ring modulator and is used to adjust the operating wavelength of the micro-ring modulator. The pilot injection unit, connected to the first heater, is used to superimpose a low-frequency pilot signal onto the heating voltage signal of the first heater, so that the optical signal output by the micro-ring modulator carries the pilot tag. The frequency of the low-frequency pilot signal corresponding to the pilot injection unit of each sub-transmitter module is unique.

[0029] In this embodiment, each sub-transmitter module includes at least a micro-ring modulator, a first heater, a pilot injection unit, and a driver. Multiple micro-ring modulators are coupled to the optical waveguide at different locations on the optical waveguide. The first heater is correspondingly located at each micro-ring modulator. Each sub-transmitter module also includes a driver, the output port of which is connected to the data channel input port of the corresponding micro-ring modulator.

[0030] The microring modulator couples out a laser beam of its target wavelength from a multi-wavelength continuous-wave laser, and modulates the coupled laser beam according to the received data signal, outputting an optical signal carrying the data. Essentially, the microring modulator is an electro-optic modulation device based on a microring resonant structure. It is optically coupled to a bus waveguide transmitting the multi-wavelength continuous-wave laser. When the resonant wavelength of the microring matches a specific wavelength of laser light in the bus waveguide, that wavelength is coupled into the microring. The microring modulator has data electrodes to receive externally input data signals and modulates the coupled laser beam by changing the refractive index of the microring. The microring modulator is small in size and has a high integration density. Its modulation power consumption is low, contributing to a reduction in the overall system power consumption.

[0031] The first heater is positioned corresponding to the micro-ring modulator and is used to adjust the operating wavelength of the micro-ring modulator. The first heater generates heat through the Joule heating effect and uses the thermo-optic effect to change the refractive index of the micro-ring, causing a shift in the resonant wavelength of the micro-ring. The heater provides the micro-ring with wavelength tuning capability, which can compensate for inconsistencies in resonant wavelength caused by manufacturing process deviations.

[0032] The pilot injection unit is connected to the first heater and superimposes a low-frequency pilot signal onto the heating voltage signal of the first heater, so that the optical signal output by the micro-ring modulator carries the pilot tag.

[0033] The low-frequency pilot signals corresponding to the pilot injection units of each sub-transmitter module are different. After receiving the injection command, the pilot injection unit generates a low-frequency voltage signal with a small amplitude. This signal is then superimposed on the heating voltage through an adder circuit and applied to the heater. The frequency of the pilot signal is much lower than that of the data signal, and its amplitude is much smaller than that of the heating voltage, so it will not affect the normal locking and data modulation functions of the micro-ring. It can be understood that the pilot signal adds an identifier to the optical signal, with different frequencies corresponding to different channels.

[0034] As an optional embodiment, the pilot injection unit includes a pilot injection determiner, a pilot generator, and a first digital-to-analog converter. After the pilot injection determiner confirms the injection command, the pilot generator of the pilot injection module generates a small low-frequency voltage signal (pilot signal) and superimposes the pilot signal on the heating voltage of the heater of the corresponding micro-ring modulator, assigning each wavelength a unique identification tag; otherwise, the pilot injection module does not generate a pilot signal.

[0035] In one exemplary embodiment, each sub-transmitting module further includes: The first photodetector is used to convert the optical signal at the download end of the micro-ring modulator into a first current signal; The first control circuit is used to adjust the heating power of the first heater according to the first current signal so as to lock the operating wavelength of the micro-ring modulator at the target wavelength.

[0036] In this embodiment, the first photodetector converts the optical signal at the download end of the micro-ring modulator into a first current signal. The micro-ring modulator splits the coupled-in light into two parts: one part continues to propagate forward, and the other part is output from the download end. The first photodetector is located at the waveguide of the download end of the micro-ring modulator, receives the optical signal from the download end of the micro-ring modulator, and converts it into a current signal through the photoelectric effect. The intensity of this current signal is proportional to the intensity of the light at the download end.

[0037] The first control circuit adjusts the heating power of the first heater based on the first current signal, locking the operating wavelength of the micro-ring modulator to the target wavelength. The first control circuit is connected to the first photodetector and the first heater, receives the first current signal, processes the received signal, and generates a control signal to drive the first heater. The first control circuit monitors changes in the light intensity at the download end to determine the alignment degree between the micro-ring and the target wavelength, and adjusts the heater power accordingly to maintain the light intensity at the download end at the target value.

[0038] During the initialization phase, the first control circuit controls the first heater to perform a power scan, linearly scanning from 0 to a predetermined maximum value. During the scan, the resonant wavelength of the microring gradually redshifts as the heating power increases. The first photodetector monitors the optical signal intensity at the microring modulator's input in real time and generates a corresponding current value. When the resonant wavelength of the microring matches a specific wavelength of a multi-wavelength continuous-wave laser, the detector outputs a current peak. Heating of the microring continues until the predetermined maximum heating power is reached. Multiple current peaks may occur during the scan, corresponding to the alignment positions of the microring with different light source wavelengths. The microcontroller records the heating power value at the time of each current peak. After the scan is complete, the microcontroller determines the minimum heating power value as the target heating power, which corresponds to the laser wavelength closest to the microring's natural resonant wavelength. The microcontroller heats the first heater according to this target heating power, coarsely locking the microring modulator's operating wavelength to the target wavelength. As an optional embodiment, after the first microring modulator's wave-locking process is completed, the wave-locking process for the second microring modulator is performed, and so on. The heater power is then continuously fine-tuned using a closed-loop feedback algorithm to keep the light intensity at the download end at the target value, achieving precise tracking and locking. Closed-loop control enables the micro-ring modulator to resist wavelength drift caused by changes in ambient temperature and device aging, ensuring long-term operational stability. The nearest-light-locking strategy selects the nearest laser wavelength as the target, requiring less heating power and saving system power consumption. The continuous fine-tuning of the closed-loop feedback ensures locking accuracy and guarantees data transmission quality.

[0039] In one exemplary embodiment, the first control circuit includes: The first transimpedance amplifier is used to convert the first current signal into a voltage signal and amplify it; The first analog-to-digital converter is used to convert the amplified voltage signal from analog to digital to obtain a digital signal. A microcontroller is used to generate a first power control signal based on a digital signal to adjust the heating power of the first heater.

[0040] In this embodiment, the first transimpedance amplifier is connected to the first photodetector, converting the weak current signal output by the detector into a voltage signal and providing gain so that the signal amplitude reaches the input range required by the analog-to-digital converter (ADC). The ADC is connected to the first transimpedance amplifier, quantizing the amplified voltage signal and converting it into a digital value that the microcontroller can process. This digital value quantifies the current light intensity at the download end. The microcontroller is connected to the ADC and the first heater, internally running a locking algorithm. The microcontroller receives the digital signal output by the ADC, analyzes the light intensity change trend to determine the alignment degree between the microring and the target wavelength, and adjusts the heating power accordingly.

[0041] In this embodiment, the first transimpedance amplifier and the analog-to-digital converter constitute the analog tuning front end, and the microcontroller constitutes the digital tuning back end. The analog tuning front end is sequentially connected to the output port of the first photodetector and the input port of the microcontroller unit.

[0042] In one exemplary embodiment, reference is made to Figure 2 The receiver includes multiple sub-receiving modules, each corresponding to a pilot tag. Each sub-receiving module is used to identify and lock the optical signal of the target wavelength according to the corresponding pilot tag, and demodulate the data from the locked optical signal of the target wavelength.

[0043] In this embodiment, the receiver includes multiple sub-receiving modules, each corresponding one-to-one with multiple pilot tags generated by the transmitter. Each sub-receiving module identifies and locks onto the optical signal of the target wavelength based on the corresponding pilot tag, and demodulates data from the locked optical signal.

[0044] Specifically, multi-wavelength optical signals from the transmitter enter the receiver's bus waveguide and pass sequentially through each sub-receiving module. Each sub-receiving module has wavelength selection and pilot detection functions, enabling it to filter out specific wavelength optical signals from the multi-wavelength optical signals and detect whether the optical signal contains a pilot tag of a specific frequency. When a target pilot tag is detected, the sub-receiving module locks the wavelength selection unit at the corresponding position and demodulates the data from the optical signal. Each sub-receiving module only receives optical signals carrying specific pilot tags, allowing the receiver to distinguish between different wavelength channels.

[0045] In one exemplary embodiment, reference is made to Figure 4 As shown, each sub-receiving module includes: Micro-ring filters are used to download optical signals corresponding to the target wavelength from multi-wavelength optical signals; The second heater is set up in correspondence with the micro-ring filter and is used to adjust the operating wavelength of the micro-ring filter; The second photodetector is used to convert the optical signal at the download end of the micro-ring filter into a second current signal; A pilot demodulator, connected to a second photodetector, is used to demodulate the corresponding pilot tag from the second current signal. The second control circuit is used to adjust the heating power of the second heater according to the demodulated pilot tag, so as to lock the operating wavelength of the micro-ring filter to the target wavelength.

[0046] Microring filters are coupled to the optical waveguide at different locations on the waveguide. They download optical signals of the corresponding target wavelength from multi-wavelength optical signals. A microring filter is a passive filter device based on a microring resonant structure. When the resonant wavelength of the microring matches an optical signal of a certain wavelength, that wavelength of optical signal is coupled into the microring and output from the download end.

[0047] The second heater is positioned corresponding to the micro-ring filter and is used to adjust the operating wavelength of the micro-ring filter. The second heater changes the resonant wavelength of the micro-ring filter through the thermo-optic effect, enabling the filter to scan and lock onto the target wavelength.

[0048] The second photodetector converts the optical signal from the download end of the microring filter into a second current signal. The second photodetector is located at the download end waveguide of the microring filter, receiving the optical signal from the download end and converting it into a current signal that simultaneously contains high-speed data components and low-frequency pilot components.

[0049] The pilot demodulator is connected to the second photodetector and demodulates the corresponding pilot tag from the second current signal. Specifically, the pilot demodulator extracts and outputs the amplitude value of the pilot signal.

[0050] The second control circuit adjusts the heating power of the second heater based on the demodulated pilot tag, locking the operating wavelength of the micro-ring filter to the target wavelength. The second control circuit determines the locking state based on the magnitude of the pilot amplitude and adjusts the heater power accordingly to keep the amplitude of the target pilot frequency at its maximum value.

[0051] In the initialization phase, a target pilot frequency is first set for each micro-loop filter, with each target pilot frequency corresponding to a pilot label. For example, the target pilot frequency f1 is set for the first micro-loop filter, and f2 is set for the second micro-loop filter. This explanation uses one micro-loop filter as an example; the operation for other micro-loop filters is similar. The heating power of the second heater is linearly scanned from 0 to a predetermined maximum value. During the scan, the pilot demodulator extracts the amplitude value of the target pilot frequency from the second current signal output by the second photodetector. Each heating power value and its corresponding amplitude value are recorded, and the heating power corresponding to the maximum amplitude value is determined as the target heating power of the second heater. The second heater is controlled to heat the micro-loop filter according to this target heating power, thereby coarsely locking the operating wavelength of the micro-loop filter to the position where the amplitude of its corresponding pilot frequency is at its maximum value. Then, the closed-loop feedback of the receiver tuning circuit is activated. By continuously fine-tuning the heater power, the amplitude of the target pilot frequency is always kept at its maximum value, achieving precise tracking and locking of the micro-loop filter's operating wavelength.

[0052] In one exemplary embodiment, the second control circuit includes: The second transimpedance amplifier is used to convert the second current signal into a first voltage signal; The second analog-to-digital converter is used to convert the first voltage signal into a digital signal; The logic controller is used to generate a second power control signal based on the digital signal and the pilot tags demodulated by the pilot demodulator; The second digital-to-analog converter is used to convert the second power control signal into an analog heating voltage to regulate the heating power of the second heater.

[0053] The second control circuit includes an analog tuning front-end and a logic controller. The analog tuning front-end is sequentially connected to the output port of the second photodetector and the input port of the digital tuning back-end. The analog tuning front-end includes a second transimpedance amplifier, a second analog-to-digital converter (ADC), and a digital-to-analog converter (DAC). The second transimpedance amplifier is a low-speed transimpedance amplifier. The logic controller and the pilot demodulator together constitute the digital tuning back-end. The logic controller is sequentially connected to the output port of the pilot demodulator and the input port of the DAC.

[0054] The second transimpedance amplifier is a low-speed transimpedance amplifier connected to the second photodetector. It is used to convert the second current signal into a first voltage signal and amplify it. This path is mainly used to extract low-frequency components from the optical signal; therefore, the second transimpedance amplifier is designed with a medium bandwidth to filter out interference from high-speed data components.

[0055] The second analog-to-digital converter is connected to the second transimpedance amplifier to convert the amplified first voltage signal into a digital signal that reflects the light intensity at the current download end and the intensity information of the pilot tag.

[0056] The logic controller is connected to a second analog-to-digital converter and a pilot demodulator to receive digital signals and the amplitude values ​​of pilot tags demodulated by the demodulator. Internally, the logic controller runs a locking algorithm to generate a second power control signal based on these two inputs.

[0057] The digital-to-analog converter is connected to the logic controller and the second heater to convert the second power control signal into an analog heating voltage, which is then applied to the second heater to regulate the heating power of the second heater.

[0058] During the initialization phase, the logic controller controls the second heater to perform a power scan, simultaneously receiving the digital signal output from the second analog-to-digital converter and the pilot amplitude value output from the pilot demodulator, recording the pilot amplitude value corresponding to each heating power point. After the scan is complete, the logic controller finds the heating power corresponding to the maximum pilot amplitude, uses this power value as the target heating power, and drives the second heater through the digital-to-analog converter to complete coarse locking. During normal operation, the logic controller continuously monitors changes in the pilot amplitude value. When the pilot amplitude decreases, it calculates the heating power that needs adjustment based on the magnitude and direction of the decrease, and fine-tunes the heating power of the second heater through the digital-to-analog converter to keep the pilot amplitude at its maximum value, achieving precise tracking and locking of the micro-ring filter's operating wavelength.

[0059] In one exemplary embodiment, each sub-receiving module further includes: The third transimpedance amplifier is used to convert the second current signal into a second voltage signal; A data receiving circuit is used to demodulate data from a second voltage signal.

[0060] This embodiment further defines the sub-receiving modules. Each sub-receiving module also includes a third transimpedance amplifier and a data receiving circuit.

[0061] The third transimpedance amplifier converts the second current signal into a second voltage signal and amplifies it. The third transimpedance amplifier is connected to the second photodetector and is connected in parallel with the second transimpedance amplifier to the output terminal of the photodetector. The third transimpedance amplifier is a high-speed transimpedance amplifier.

[0062] The data receiving circuit demodulates the data from the second voltage signal. Connected to a third transimpedance amplifier, the data receiving circuit receives the amplified data signal and converts the high-speed serial data into parallel data through functions such as limiting amplification and clock data recovery for subsequent circuit processing.

[0063] In another exemplary embodiment, each sub-receiving module includes: A cascaded multi-micro-ring filter, and multiple second heaters configured one-to-one with the cascaded multi-micro-ring filter; The second photodetector is used to convert the optical signal at the download end of the last micro-loop filter of the cascaded multi-micro-loop filter into a second current signal; A pilot demodulator, connected to a second photodetector, is used to demodulate the corresponding pilot tag from the second current signal. The second control circuit is used to adjust the heating power of multiple second heaters according to the demodulated pilot tags in order to lock the operating wavelength of the cascaded multi-micro-ring filter to the target wavelength.

[0064] Each sub-receiving module includes a cascaded multi-micro-ring filter and multiple second heaters, each corresponding to one of the cascaded multi-micro-ring filters. (Refer to...) Figure 5 Taking a dual-micro-ring filter as an example, each sub-receiver module contains two micro-ring filters, denoted as the first micro-ring filter 1-1 and the second micro-ring filter 1-2, and two corresponding heaters, denoted as the first heater 2-1 and the second heater 2-2, respectively. (Refer to...) Figure 6 Taking a three-micro-ring filter as an example, each sub-receiving module contains three micro-ring filters, referred to as the first micro-ring filter 1-1, the second micro-ring filter 1-2, and the third micro-ring filter 1-3, and three corresponding heaters, referred to as the first heater 2-1, the second heater 2-2, and the third heater 2-3.

[0065] The cascaded multi-micro-ring filter is coupled to the bus waveguide that transmits multi-wavelength optical signals. Its resonant wavelength is adjusted to near the target wavelength by the corresponding heater, and the optical signal of the target wavelength is coupled out from the bus waveguide.

[0066] The second photodetector is specifically used to convert the optical signal at the download end of the last micro-ring filter into a second current signal.

[0067] The above-mentioned cascaded multi-micro-ring filter structure achieves the micro-ring filtering function, making the overall roll-off characteristics of the filter steeper, the passband shape flatter, and the channel selectivity and crosstalk suppression capability significantly improved. It is especially suitable for ultra-dense wavelength division multiplexing systems with extremely small channel spacing.

[0068] In summary, this application introduces a pilot injection unit in the sub-transmitter module. After the micro-ring modulator completes wavelength scanning and proximity wavelength locking, the pilot injection unit injects pilot signals through the heater of the micro-ring modulator, assigning a unique identifier to each wavelength at the transmitter. A pilot demodulator is introduced in the sub-receiver module. The demodulator extracts the amplitude value of the target pilot frequency corresponding to each micro-ring filter by demodulating the current value output from the photodiode at the download end of the corresponding micro-ring filter. Combined with a logic controller, this achieves accurate identification and locking of the operating wavelength of the micro-ring filter. This effectively solves the difficulties in channel identification and the risk of incorrect wavelength locking in micro-ring wavelength division multiplexing systems, significantly improving the stability and reliability of the overall interconnect system. Because this application achieves accurate wavelength identification and locking in the micro-ring wavelength division multiplexing optical interconnect system, it effectively alleviates the locking difficulties caused by thermal coupling and signal crosstalk between multiple micro-rings, effectively improving the overall system scalability and supporting a larger number of wavelength channels. Simultaneously, the transmitter's micro-ring modulator achieves proximity wavelength locking, effectively reducing the thermal tuning power consumption of the micro-ring modulator.

[0069] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0070] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wavelength division multiplexing optical interconnect system, characterized in that, include: A multi-wavelength light source is used to generate and output multi-wavelength continuous wave laser, wherein the multi-wavelength continuous wave laser comprises multiple lasers with preset wavelength intervals. A transmitter is used to receive the multi-wavelength continuous wave laser, load data onto each wavelength of the multi-wavelength continuous wave laser to generate multi-wavelength optical signals, and add a unique pilot label to each wavelength of the optical signal. A receiver is used to receive the multi-wavelength optical signals, identify the target wavelength optical signal based on the pilot tags carried by each wavelength optical signal, and lock and demodulate the data in the target wavelength optical signal.

2. The wavelength division multiplexing optical interconnect system according to claim 1, characterized in that, The transmitter includes multiple sub-transmitting modules, each corresponding to a multiple wavelength. Each sub-transmitting module is used to receive the multi-wavelength continuous wave laser, extract the laser corresponding to the target wavelength from the multi-wavelength continuous wave laser, load data onto the laser to generate an optical signal, and add a unique pilot label to the optical signal.

3. The wavelength division multiplexing optical interconnect system according to claim 2, characterized in that, Each of the sub-transmission modules includes: A micro-ring modulator is used to couple out laser light of its own target wavelength from the multi-wavelength continuous wave laser, and modulate the coupled laser light according to the received data signal to output an optical signal carrying data. A first heater is provided corresponding to the micro-ring modulator and is used to adjust the operating wavelength of the micro-ring modulator. A pilot injection unit, connected to the first heater, is used to superimpose a low-frequency pilot signal onto the heating voltage signal of the first heater, so that the optical signal output by the micro-ring modulator carries a pilot tag; The frequency of the low-frequency pilot signal corresponding to the pilot injection unit of each of the sub-transmitting modules is unique.

4. The wavelength division multiplexing optical interconnect system according to claim 3, characterized in that, Each of the sub-transmission modules further includes: The first photodetector is used to convert the optical signal at the download end of the micro-ring modulator into a first current signal; A first control circuit is used to adjust the heating power of the first heater according to the first current signal, so as to lock the operating wavelength of the micro-ring modulator at the target wavelength.

5. The wavelength division multiplexing optical interconnect system according to claim 4, characterized in that, The first control circuit includes: A first transimpedance amplifier is used to convert the first current signal into a voltage signal and amplify it; The first analog-to-digital converter is used to convert the amplified voltage signal from analog to digital to obtain a digital signal. A microcontroller is configured to generate a first power control signal based on the digital signal to adjust the heating power of the first heater.

6. The wavelength division multiplexing optical interconnect system according to claim 1, characterized in that, The receiver includes multiple sub-receiving modules, each corresponding to a multiple pilot tags. Each sub-receiving module is used to identify and lock the optical signal of the target wavelength according to the corresponding pilot tag, and demodulate data from the locked optical signal of the target wavelength.

7. The wavelength division multiplexing optical interconnect system according to claim 6, characterized in that, Each of the sub-receiving modules includes: A micro-ring filter is used to download an optical signal corresponding to the target wavelength from the multi-wavelength optical signal; The second heater is configured corresponding to the micro-ring filter and is used to adjust the operating wavelength of the micro-ring filter. The second photodetector is used to convert the optical signal at the download end of the micro-ring filter into a second current signal; A pilot demodulator, connected to the second photodetector, is used to demodulate the corresponding pilot tag from the second current signal; The second control circuit is used to adjust the heating power of the second heater according to the demodulated pilot tag, so as to lock the operating wavelength of the micro-ring filter to the target wavelength.

8. The wavelength division multiplexing optical interconnect system according to claim 7, characterized in that, The second control circuit includes: A second transimpedance amplifier is used to convert the second current signal into a first voltage signal; A second analog-to-digital converter is used to convert the first voltage signal into a digital signal; A logic controller is configured to generate a second power control signal based on the digital signal and the pilot tag demodulated by the pilot demodulator; A second digital-to-analog converter is used to convert the second power control signal into an analog heating voltage to adjust the heating power of the second heater.

9. The wavelength division multiplexing optical interconnect system according to claim 7, characterized in that, Each of the sub-receiving modules further includes: A third transimpedance amplifier is used to convert the second current signal into a second voltage signal; A data receiving circuit is used to demodulate data from the second voltage signal.

10. The wavelength division multiplexing optical interconnect system according to claim 6, characterized in that, Each of the sub-receiving modules includes: A cascaded multi-micro-ring filter, and a plurality of second heaters configured in a one-to-one correspondence with the cascaded multi-micro-ring filter; The second photodetector is used to convert the optical signal at the download end of the last micro-ring filter of the cascaded multi-micro-ring filter into a second current signal. A pilot demodulator, connected to the second photodetector, is used to demodulate the corresponding pilot tag from the second current signal; The second control circuit is used to adjust the heating power of multiple second heaters according to the demodulated pilot tags, so as to lock the operating wavelength of the cascaded multi-micro-ring filter to the target wavelength.

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