Micro-ring resonator wavelength locking method and device, electronic equipment and storage medium

Abstract

This invention provides a wavelength locking method, apparatus, electronic device, and storage medium for microring resonators (MRRs). It can be used for joint scanning and locking control of high-Q second-order CROW filters. The locking time is less than 2 milliseconds, and the wavelength locker can operate across the entire C-band. An FPGA is used as the controller. In scanning mode, the wavelength of the CROW filter is scanned, causing the output power of the lower port of the CROW filter to quickly reach near its maximum value. In locking mode, a PID control algorithm adjusts the power applied to the microheater to maximize the output power of the lower port of the CROW filter. This method has excellent scalability and can be easily applied to higher-order MRRs. When the wavelength control loop is enabled, the resonant stability and laser wavelength drift tolerance of the CROW filter can be significantly enhanced.

Description

Technical Field

[0001] This invention relates to the field of CROW (Coupled-Resonator Optical Waveguide Filter) filter technology, and in particular to a method, apparatus, electronic device, and storage medium for wavelength locking of a microring resonator. Background Technology

[0002] With the development of emerging applications such as the Internet of Things (IoT), cloud computing, and artificial intelligence (AI), short-range optical links are continuously improving communication speeds in various scenarios, including access, mobile fronthaul, and data center networks. Meanwhile, silicon photonic integrated circuits (SiPICs) have attracted widespread attention due to their low cost, compact size, and high bandwidth. Micro-ring resonators (MRRs), as key components of SiPICs, have been extensively explored in optical communication and sensing applications due to their high sensitivity, design flexibility, and low power consumption.

[0003] However, the resonant wavelength of microring resonators (MRRs) is prone to drift due to temperature fluctuations. Although several wavelength locking techniques for MRRs have been reported, such as the jitter signal method, the improved saddle point search method, and the neural network method, most of these works focus on locking low Q-value (quality factor) MRRs. There are currently no reports on wavelength locking for high Q-value MRRs in the context of high-speed optical communication. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide a wavelength locking method, apparatus, electronic device and storage medium for microring resonators to perform wavelength locking on high Q-value MRRs.

[0005] In a first aspect, embodiments of the present invention provide a wavelength locking method for a microring resonator. A coupled resonator optical waveguide filter contains multiple microring resonators. The method includes: injecting laser output from a laser into the coupled resonator optical waveguide filter; the lower end of the coupled resonator optical waveguide filter outputs optical power; the optical power output from the lower end is converted into a digital electrical signal, which is input to a field-programmable gate array (FPGA); the FPGA scans the thermal power of the microring resonators and switches operating modes based on the thermal power and the digital electrical signal; when the operating mode is scanning mode, the FPGA adjusts the thermal power through iterative binary division to track the target wavelength, generating a control signal; when the operating mode is locking mode, the FPGA locks the resonant wavelength through proportional, integral, and derivative operations, generating a control signal; the control signal is fed back to the coupled resonator optical waveguide filter so that the coupled resonator optical waveguide filter adjusts its output optical power based on the control signal.

[0006] In an optional embodiment of this application, the step of the laser-injected coupled resonator optical waveguide filter output from the laser includes: polarization control of the laser input polarization controller output from the laser; grating coupling of the laser input grating coupler output from the polarization controller; and laser-injected coupled resonator optical waveguide filter output from the grating coupler.

[0007] In an optional embodiment of this application, the step of outputting optical power at the upper and lower ports of the coupled resonator optical waveguide filter includes: the upper port of the coupled resonator optical waveguide filter outputting a first proportion of optical power; and the lower port of the coupled resonator optical waveguide filter outputting a second proportion of optical power; wherein the first proportion is greater than the second proportion.

[0008] In an optional embodiment of this application, after the step of outputting a first proportion of optical power at the upper port of the coupled resonator optical waveguide filter, the method further includes: inputting the optical power output at the upper port into a spectrometer.

[0009] In an optional embodiment of this application, the step of converting the optical power output from the downstream port into a digital electrical signal includes: inputting the optical power output from the downstream port into a photodetector to output an electrical signal; inputting the electrical signal into a transimpedance amplifier to output an amplified electrical signal; and inputting the amplified electrical signal into an analog-to-digital converter to output a digitized electrical signal.

[0010] In an optional embodiment of this application, the above-mentioned step of switching the working mode based on thermal power and digital electrical signal includes: determining the maximum optical output power of the downstream port based on thermal power; if the ratio of the optical power represented by the digital electrical signal to the maximum optical output power is greater than or equal to a preset threshold, determining the working mode as a locked mode; if the ratio of the optical power represented by the digital electrical signal to the maximum optical output power is less than the threshold, determining the working mode as a scanning mode.

[0011] In an optional embodiment of this application, the step of feeding the control signal back to the coupled resonator optical waveguide filter includes: inputting the control signal into a digital-to-analog converter and outputting an analog control signal; inputting the analog control signal into a low-noise amplifier and outputting a driving voltage; feeding the driving voltage back to the heater of the coupled resonator optical waveguide filter; and the heater performing thermal tuning feedback on the micro-ring resonator based on the driving voltage.

[0012] Secondly, embodiments of the present invention also provide a microring resonator wavelength locking device. A coupled resonator optical waveguide filter contains multiple microring resonators. The device includes: an optical power output module for injecting laser output from a laser into the coupled resonator optical waveguide filter, wherein the upper and lower ports of the coupled resonator optical waveguide filter output optical power respectively; a digital electrical signal processing module for converting the optical power output from the lower port into a digital electrical signal, which is input to a field-programmable gate array (FPGA); a working mode switching module for the FPGA to scan the thermal power of the microring resonators and switch the working mode based on the thermal power and the digital electrical signal; a scanning mode processing module for adjusting the thermal power to track the target wavelength using an iterative binary search method when the working mode is scanning mode, generating a control signal; a locking mode processing module for locking the resonant wavelength using a proportional, integral, and derivative method when the working mode is locking mode, generating a control signal; and a control signal feedback module for feeding the control signal back to the coupled resonator optical waveguide filter so that the coupled resonator optical waveguide filter adjusts its output optical power based on the control signal.

[0013] Thirdly, embodiments of the present invention also provide an electronic device, including a processor and a memory, wherein the memory stores computer-executable instructions that can be executed by the processor, and the processor executes the computer-executable instructions to implement the above-described microring resonator wavelength locking method.

[0014] Fourthly, embodiments of the present invention also provide a computer-readable storage medium storing computer-executable instructions. When the computer-executable instructions are invoked and executed by a processor, the computer-executable instructions cause the processor to implement the aforementioned microring resonator wavelength locking method.

[0015] The embodiments of the present invention bring the following beneficial effects: This invention provides a wavelength locking method, apparatus, electronic device, and storage medium for microring resonators (MRRs). It can be used for joint scanning and locking control of high-Q second-order CROW filters. The locking time is less than 2 milliseconds, and the wavelength locker can operate across the entire C-band. A field-programmable gate array (FPGA) is used as the controller. In scanning mode, the wavelength of the CROW filter is scanned, causing the output power of the lower port of the CROW filter to quickly reach near its maximum value. In locking mode, a proportional-integral-differential (PID) control algorithm is used to adjust the power applied to the microheater, maximizing the output power of the lower port of the CROW filter. This method has excellent scalability and can be easily applied to higher-order MRRs. When the wavelength control loop is enabled, the resonant stability and laser wavelength drift tolerance of the CROW filter can be significantly enhanced. Finally, by employing adaptive wavelength tracking, the Carrier Extraction Self-Coherent (CESC) system based on the CROW filter can achieve a transmission rate of 224 Gb / s over 50 km of standard single-mode fiber (SSMF).

[0016] Other features and advantages of this disclosure will be set forth in the following description, or some features and advantages may be inferred from the description or determined without doubt, or may be learned by practicing the techniques described above.

[0017] To make the above-mentioned objects, features and advantages of this disclosure more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 A flowchart of a microring resonator wavelength locking method provided in an embodiment of the present invention; Figure 2 A schematic diagram of a wavelength locking method for a microring resonator provided in an embodiment of the present invention; Figure 3A schematic diagram of a microring resonator wavelength locking system provided in an embodiment of the present invention; Figure 4 A schematic diagram showing the spectral response of a CROW filter provided in an embodiment of the present invention; Figure 5 A schematic diagram of a dual-ring wavelength tracking process provided in an embodiment of the present invention; Figure 6 A schematic diagram of an algorithm for a wavelength tracking process provided in an embodiment of the present invention; Figure 7 A schematic diagram of convergence time provided for an embodiment of the present invention; Figure 8 A schematic diagram illustrating the relationship between output optical power and ambient temperature, provided for an embodiment of the present invention; Figure 9 A schematic diagram illustrating the wavelength locking result of a high-Q CROW filter provided in an embodiment of the present invention; Figure 10 This is a schematic diagram of the structure of a microring resonator wavelength locking device provided in an embodiment of the present invention; Figure 11 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Several wavelength locking techniques for MRRs have been reported so far, for example: 1. Jitter Signal Method: A jitter signal and a DC signal are jointly applied to the integrated heater, causing the jitter to be modulated into the response of the micro-ring resonator. By demodulating the jitter signal, an antisymmetric response curve can be obtained. This curve can accurately reflect the resonant state of the micro-ring resonator, and can then be used to adjust the heating power, achieving real-time monitoring and optimized control of the micro-ring's operating point.

[0022] 2. Improved saddle point search method: By changing the phase shift to adjust the locking point, it is possible to lock onto the resonant center or onto both sides of the resonant center.

[0023] 3. Neural Network Method: Two three-layer artificial neural networks are used to control two micro-ring resonators respectively. The neural networks are trained to learn the relationship between the PD (photodetector) signal and the tuning control signal and automatically predict the tuning voltage.

[0024] However, the wavelength locking techniques mentioned above all have corresponding technical defects, making it difficult to lock wavelengths for high Q-value MRRs. For example, the dithering signal method interferes with the resonator, the improved saddle point search method has too many PDs, and the locking range of the neural network method is small.

[0025] Based on this, the present invention provides a wavelength locking method, apparatus, electronic device and storage medium for microring resonators, specifically providing a wavelength locking method for high-Q microring resonators, which has excellent scalability and can be easily applied to higher-order MRRs.

[0026] To facilitate understanding of this embodiment, a wavelength locking method for a microring resonator disclosed in this embodiment of the invention will first be described in detail.

[0027] Example 1: This invention provides a wavelength locking method for microring resonators. Multiple microring resonators are incorporated in a coupled resonator optical waveguide filter. (See also...) Figure 1 The flowchart shown illustrates a wavelength locking method for a microring resonator, which includes the following steps: In step S101, the laser output from the laser is injected into the coupled resonator optical waveguide filter, and the upper and lower ports of the coupled resonator optical waveguide filter output optical power respectively.

[0028] In this embodiment, the laser output from the laser can be injected into the CROW filter, and the upper and lower ports of the CROW filter can output optical power respectively.

[0029] In some embodiments, the laser output from the laser is input to a polarization controller for polarization control; the laser output from the polarization controller is input to a grating coupler for grating coupling; and the laser output from the grating coupler is injected into a resonator to couple to an optical waveguide filter.

[0030] See Figure 2 The diagram shows a wavelength locking method for a microring resonator, in which the laser wavelength output from the laser can be injected into the CROW filter after passing through a polarization controller (PC) and a grating coupler (GC) in sequence.

[0031] In some embodiments, the upper port of the coupled resonator optical waveguide filter outputs a first proportion of optical power; the lower port of the coupled resonator optical waveguide filter outputs a second proportion of optical power; wherein the first proportion is greater than the second proportion.

[0032] like Figure 2 As shown, the CROW filter outputs 90% optical power at the upper port and 10% optical power at the lower port, meaning the first ratio can be 90% and the second ratio can be 10%.

[0033] In some embodiments, the optical power output from the uplink port is input to the spectrometer.

[0034] like Figure 2 As shown, 90% of the optical power output from the upper port is input into the optical spectrum analyzer (OSA).

[0035] In step S102, the optical power output from the downstream port is converted into a digital electrical signal, and the digital electrical signal is input into a field-programmable gate array.

[0036] In this embodiment, the optical power output from the downstream port of the CROW filter can be converted into a digital electrical signal, which can be input into the FPGA for processing.

[0037] In some embodiments, the optical power output from the lower port is input to a photodetector to output an electrical signal; the electrical signal is input to a transimpedance amplifier to output an amplified electrical signal; and the amplified electrical signal is input to an analog-to-digital converter to output a digitized electrical signal.

[0038] like Figure 2 As shown, 10% of the optical power output from the lower port is converted into an electrical signal by a photodetector (PD), and then amplified by a transimpedance amplifier (TIA) and converted into an analog-to-digital converter (ADC) to output a digital electrical signal.

[0039] Step S103: The field-programmable gate array scans the thermal power of the microring resonator and switches the operating mode based on the thermal power and digital electrical signal.

[0040] In this embodiment, the FPGA can scan the thermal power of the MRR and switch the operating mode based on the thermal power and the input digital electrical signal. The operating mode can be a scanning mode or a locked mode.

[0041] In some embodiments, the maximum optical output power of the downstream port is determined based on thermal power; if the ratio of the optical power represented by the digital electrical signal to the maximum optical output power is greater than or equal to a preset threshold, the operating mode is determined to be a locked mode; if the ratio of the optical power represented by the digital electrical signal to the maximum optical output power is less than the threshold, the operating mode is determined to be a scanning mode.

[0042] like Figure 2As shown, if the ratio of the optical power represented by the digital electrical signal to the maximum optical output power is greater than or equal to the threshold of 90%, the working mode is determined to be the lock mode; if the ratio is less than the threshold of 90%, the working mode is determined to be the scan mode.

[0043] Step S104: When the working mode is scanning mode, the field programmable gate array adjusts the thermal power to track the target wavelength by iterative binary division and generates a control signal.

[0044] This embodiment provides a joint scanning and locking control method for high-Q second-order CROW filters (i.e., Figure 2 (JSAL algorithm in the text).

[0045] like Figure 2 As shown, in the JSAL algorithm, when the working mode is scanning mode, the FPGA can adjust the thermal power through the iterative binary search method to track the target wavelength and generate a control signal.

[0046] Among them, the iterative bisection method is a numerical method for solving the roots of nonlinear equations. It approximates the exact solution by continuously narrowing the interval containing the roots.

[0047] Step S105: When the operating mode is locked, the field programmable gate array locks the resonant wavelength by proportional, integral, and derivative methods to generate a control signal.

[0048] like Figure 2 As shown, in the JSAL algorithm, when the working mode is locked, the FPGA can lock the resonant wavelength and fine-tune it using the PID method to generate a control signal.

[0049] The PID method is a closed-loop control algorithm that precisely adjusts the system output through three stages: proportional, integral, and derivative. It calculates the error between the target value and the actual value in real time and dynamically adjusts the control input based on the historical, current, and future trends of the error, enabling the system output to quickly and accurately track the target value.

[0050] In step S106, the control signal is fed back to the coupled resonator optical waveguide filter so that the coupled resonator optical waveguide filter adjusts the output optical power based on the control signal.

[0051] In this embodiment, the control signal generated by the FPGA can be fed back to the CROW filter, and the CROW filter can adjust the output optical power according to the control signal.

[0052] In some embodiments, a control signal is input to a digital-to-analog converter and outputs an analog control signal; the analog control signal is input to a low-noise amplifier and outputs a drive voltage; the drive voltage is fed back to the heater of the coupled resonator optical waveguide filter; the heater performs thermal tuning feedback on the micro-ring resonator based on the drive voltage.

[0053] like Figure 2 As shown, the control signal is amplified sequentially by a digital-to-analog converter (DAC) and then amplified into a drive voltage by a low-noise amplifier (LNA). The drive voltage is input to the heater of the CROW filter for thermal tuning feedback.

[0054] This invention provides a wavelength locking method for microring resonators (MRRs), which can be used for joint scanning and locking control of high-Q second-order CROW filters. The locking time of this method is less than 2 milliseconds, and the wavelength locker can operate throughout the entire C-band. An FPGA is used as the controller. In scanning mode, the wavelength of the CROW filter is scanned, causing the output power of the lower port of the CROW filter to quickly reach near its maximum value. In locking mode, a PID control algorithm adjusts the power applied to the microheater to maximize the output power of the lower port of the CROW filter. This method has excellent scalability and can be easily applied to higher-order MRRs. When the wavelength control loop is enabled, the resonant stability and laser wavelength drift tolerance of the CROW filter can be significantly enhanced. Finally, by employing adaptive wavelength tracking, a CESC system based on the CROW filter can achieve a transmission rate of 224 Gb / s over a 50 km SSMF.

[0055] Example 2: This embodiment provides another wavelength locking method for microring resonators, which is implemented based on the above embodiment and can be applied to the wavelength locking system of microring resonators. This embodiment focuses on describing the core signal path of the wavelength locking system of microring resonators.

[0056] See also Figure 3 The diagram shows a wavelength-locked microring resonator system. In this embodiment, the coupled resonator optical waveguide filter incorporates two microring resonators (microring 1 and microring 2). Lc = 20µm, R = 120µm.

[0057] like Figure 3As shown, the laser light passes through a polarization controller (PC), a grating coupler (GC), and enters the CROW filter. 10% of the output from the lower port is converted into an electrical signal by an InGaAs photodetector (PD). This electrical signal is then processed sequentially by a transimpedance amplifier (TIA), a 16-bit ADC (<5µs), and an FPGA (model EP4CE75F2317). The control signal generated by the FPGA based on the JSAL algorithm is then converted by a 14-bit DAC (8ns) and amplified by a low-noise amplifier (LNA) into a drive voltage, which is finally fed back to the CROW filter to achieve precise wavelength locking. Figure 3 FWHM in the figure represents the full width at half maximum (FWHM).

[0058] See Figure 4 The diagram shows the spectral response of a CROW filter with a free spectral range (FSR) of approximately 0.8 nm, a 3 dB bandwidth of 1.26 GHz, a high extinction ratio (ER) of 60 dB, and a corresponding Q value exceeding 150,000 [6,264].

[0059] See Figure 5 The diagram illustrates a dual-ring wavelength tracking process. During initialization, the photocurrent values ​​are stored and compared using a FIFO (First In First Out) memory, and the thermal power applied to the MRR is scanned to find the maximum optical output power at the lower port. After initialization, the algorithm sequentially controls the resonant wavelengths of micro-ring 1 and micro-ring 2. The control operations of the two ring cavities are continuous and cyclical, following a sliding window mechanism.

[0060] In each control cycle, the wavelength tracking process includes a scanning mode and a locking mode. In scanning mode, the system tracks the target wavelength by adjusting the thermal power using an iterative binary search method. Once the optical power reaches 90% of the maximum value obtained during initialization, the system switches to locking mode for fine-tuning. In locking mode, the feedback loop uses a PID method to lock the resonant wavelength. To avoid wavelength tracking loss due to wavelength drift or thermal fluctuations in this embodiment, upper and lower thresholds for the error signal are also set to enable mode switching and reset.

[0061] See Figure 6 The diagram shows an algorithm for a wavelength tracking process. Figure 6 The specific algorithms for ScanMode and LockMode are shown. The parameters in each formula are as follows: P H (t): Power consumption in the heater; ΔP H(t): Power change in the heater; I(t): Output intensity; I0: Maximum light intensity (under ideal conditions: output power after the laser wavelength is aligned with the microring resonant wavelength); error(t): Error signal (the difference between I0 and the acquired I(t); i: Step size adjustment coefficient; A: Responsivity of the photodetector; Kp: Proportional coefficient of PID (integral and derivative coefficients are set to 0).

[0062] like Figure 6 As shown, in Scan Mode, P H (t=0)=0, indicating that the heater power consumption is set to 0 at the initial moment; P H (t=0)= P C The heating step change in the characterization scanning mode is P C ( P C (i is a constant); i=1 indicates that the initial value of the step size adjustment coefficient is 1.

[0063] like Figure 6 As shown, error(t=0)=0, indicating that the initial time error is 0; P H (t+1)=P H (t)+ P H (t) / i represents the output power at time t+1, which is equal to the power at time t plus the step change. P C error(t+1) = error(t) represents delaying the error from the previous time step, i.e., the error at time t+1 is equal to the error at time t, so that subsequent comparisons can be made.

[0064] like Figure 6 As shown, if: I(t+1)≥90%I0, it indicates that the condition has passed through P. H After applying power at (t+1), does the generated light intensity satisfy 90% of I0 (maximum light intensity)? If so, jump to lock mode; otherwise, continue in scan mode; error(t+2) = 90%I0 - I(t0); after P H The error signal generated after applying power at (t+1) is 90% of I0 (maximum light intensity) minus the light intensity at the current moment.

[0065] like Figure 6As shown, `If:error(t+2)≥5000;` indicates that there may be large fluctuations, so continue debugging with larger steps, i.e., `i=1`; otherwise, jump to the next IF statement `If:error(t+2)≤error(t+1)`. If this is true, it means the direction is correct, and continue with P. H (t+1)=P H (t)+ P H (t) / i, otherwise, it means the direction is reversed, so reduce the step size and invert the step size, i.e., i = i + 1. P H (t)=- P H (t).

[0066] like Figure 6 As shown, in Lock Mode, A = 0.95 A / W, characterizing the responsivity of the photodetector as a constant of 0.95 A / W; P H (t)=A×(I(t)-I0), representing the step change in the locked mode, which is equal to the difference between the collected light intensity and the ideal light intensity.

[0067] like Figure 6 As shown, P H (t+1)=P H (t)+ Kp× P H (t); represents the output power at time t+1, which is equal to the power at time t + the step change Kp × P C Kp× P C This represents the proportionality coefficient multiplied by the change in error, and is a dynamically changing value.

[0068] like Figure 6 As shown, error(t+1) = error(t) delays the error from the previous time step, meaning the error at time t+1 equals the error at time t, for subsequent comparisons; error(t+2) = I0 - I(t) is processed by P H The error signal generated after applying power at (t+1) is I0 (maximum light intensity) - light intensity at the current moment; If: error(t+2) ≥ 2000, it indicates that there may be a large fluctuation, jump to scanning mode; otherwise, continue to compare. If: error(t+2) ≤ error(t+1), if it is true, it means that the direction is correct, continue; otherwise, reverse the step. P H (t)=- PH (t).

[0069] See Figure 7 The diagram illustrates a convergence time, where the convergence time of a single micro-ring is less than 0.5 milliseconds. To address the issue of light source power fluctuations, 1% of the input optical power can be used to normalize the light source power fluctuations. After normalization, the wavelength tracking performance of the dual-ring system is further improved, and the convergence time is shortened to less than 2 milliseconds.

[0070] See Figure 8 The diagram shown illustrates the relationship between output optical power and ambient temperature. Figure 8 The relationship between output optical power and ambient temperature is shown within an ambient temperature range of 20°C to 30°C, with the temperature linearly scanned over 10 hours. Stable wavelength tracking was maintained throughout the 10-hour period.

[0071] See Figure 9 The diagram shows the wavelength locking results of a high-Q CROW filter. The transmission spectrum of the CROW filter was measured in the wavelength range of 1530 to 1565 nm (5 nm wavelength intervals) without the use of a TEC (Thermo Electric Cooler). Figure 9 The figure above also shows the spectrum in 0.1 nm steps within the FSR range.

[0072] Example 3: Corresponding to the above method embodiments, this invention provides a microring resonator wavelength locking device, wherein multiple microring resonators are disposed in the coupled resonator optical waveguide filter, see [link to documentation]. Figure 10 The diagram shown illustrates the structure of a wavelength-locking device for a microring resonator. This device includes: The optical power output module 1001 is used for the laser injection coupler waveguide filter for laser output. The upper and lower ports of the coupler waveguide filter output optical power respectively. Digital signal processing module 1002 is used to convert the optical power output from the downstream port into digital electrical signals, and the digital electrical signals are input to a field-programmable gate array; The working mode switching module 1003 is used to scan the thermal power of the micro-ring resonator using a field-programmable gate array, and to switch the working mode based on the thermal power and digital electrical signal. The scanning mode processing module 1004 is used to generate a control signal by adjusting the thermal power of the field programmable gate array to track the target wavelength through iterative binary division when the working mode is scanning mode. The locking mode processing module 1005 is used to lock the resonant wavelength by proportional, integral and derivative methods and generate control signals when the working mode is locked mode. The control signal feedback module 1006 is used to feed the control signal back to the coupled resonator optical waveguide filter so that the coupled resonator optical waveguide filter adjusts the output optical power based on the control signal.

[0073] This invention provides a microring resonator wavelength locking device for the joint scanning and locking control of high-Q second-order CROW filters. The locking time is less than 2 milliseconds, and the wavelength locker can operate across the entire C-band. An FPGA is used as the controller. In scanning mode, the CROW filter wavelength is scanned, causing the output power of the lower port of the CROW filter to quickly reach near its maximum value. In locking mode, a PID control algorithm adjusts the power applied to the microheater to maximize the output power of the lower port of the CROW filter. This method has excellent scalability and can be easily applied to higher-order MRRs. When the wavelength control loop is enabled, the resonant stability and laser wavelength drift tolerance of the CROW filter are significantly enhanced. Finally, by employing adaptive wavelength tracking, a CESC system based on the CROW filter can achieve a transmission rate of 224 Gb / s over a 50 km SSMF.

[0074] The aforementioned optical power output module is used for polarization control of the laser output from the laser input polarization controller; for grating coupling of the laser output from the polarization controller into the grating coupler; and for laser injection coupling resonator optical waveguide filter output from the grating coupler.

[0075] The aforementioned optical power output module is used to output a first proportion of optical power at the upper port of the coupled resonator optical waveguide filter and a second proportion of optical power at the lower port of the coupled resonator optical waveguide filter; wherein the first proportion is greater than the second proportion.

[0076] The aforementioned device includes: a spectrum analyzer input module for inputting the optical power output from the uplink port into the spectrum analyzer.

[0077] The aforementioned digital electrical signal processing module is used to input the optical power output from the lower port into the photodetector to output an electrical signal; input the electrical signal into the transimpedance amplifier to output an amplified electrical signal; and input the amplified electrical signal into the analog-to-digital converter to output a digitized electrical signal.

[0078] The aforementioned working mode switching module is used to determine the maximum optical output power of the downstream port based on thermal power; if the ratio of the optical power represented by the digital electrical signal to the maximum optical output power is greater than or equal to a preset threshold, the working mode is determined to be the lock mode; if the ratio of the optical power represented by the digital electrical signal to the maximum optical output power is less than the threshold, the working mode is determined to be the scan mode.

[0079] The aforementioned control signal feedback module is used to input control signals to the digital-to-analog converter and output analog control signals; the analog control signals are input to a low-noise amplifier and output a drive voltage; the drive voltage is fed back to the heater of the coupled resonator optical waveguide filter; the heater performs thermal tuning feedback on the micro-ring resonator based on the drive voltage.

[0080] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the microring resonator wavelength locking device described above can be referred to the corresponding process in the aforementioned embodiments of the microring resonator wavelength locking method, and will not be repeated here.

[0081] Example 4: This invention also provides an electronic device for running the above-described microring resonator wavelength locking method; see [link to previous document]. Figure 11 The diagram shows the structure of an electronic device, which includes a memory 100 and a processor 101. The memory 100 is used to store one or more computer instructions, which are executed by the processor 101 to implement the above-mentioned microring resonator wavelength locking method.

[0082] Furthermore, Figure 11 The electronic device shown also includes a bus 102 and a communication interface 103, with the processor 101, the communication interface 103 and the memory 100 connected via the bus 102.

[0083] The memory 100 may include high-speed random access memory (RAM) and may also include non-volatile memory, such as at least one disk storage device. Communication between this system network element and at least one other network element is achieved through at least one communication interface 103 (which can be wired or wireless), such as the Internet, wide area network, local area network, metropolitan area network, etc. The bus 102 may be an ISA bus, PCI bus, or EISA bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 11 The symbol is represented by a single double-headed arrow, but this does not mean that there is only one bus or one type of bus.

[0084] Processor 101 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be completed by the integrated logic circuitry in the hardware of processor 101 or by instructions in software form. Processor 101 can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this invention can be directly manifested as execution by a hardware decoding processor, or execution by a combination of hardware and software modules in the decoding processor. The software module can reside in a readily available storage medium in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory 100, and processor 101 reads information from memory 100 and, in conjunction with its hardware, completes the steps of the method described in the foregoing embodiments.

[0085] This invention also provides a computer-readable storage medium storing computer-executable instructions. When these computer-executable instructions are called and executed by a processor, they cause the processor to implement the aforementioned microring resonator wavelength locking method. For details of the implementation, please refer to the method embodiments, which will not be repeated here.

[0086] The computer program product of the microring resonator wavelength locking method, apparatus and electronic device provided in the embodiments of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods in the preceding method embodiments. For specific implementation, please refer to the method embodiments, which will not be repeated here.

[0087] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system and / or device described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0088] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0089] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0090] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0091] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A wavelength locking method for a microring resonator, characterized in that, The coupled resonator optical waveguide filter incorporates multiple micro-ring resonators, and the method includes: The laser output from the laser is injected into the coupled resonator optical waveguide filter, and the upper and lower ports of the coupled resonator optical waveguide filter output optical power respectively; The optical power output from the downstream port is converted into a digital electrical signal, and the digital electrical signal is input into a field-programmable gate array. The field-programmable gate array scans the thermal power of the micro-ring resonator and switches the operating mode based on the thermal power and the digital electrical signal. When the operating mode is scanning mode, the field-programmable gate array adjusts the thermal power to track the target wavelength by iterative binary division and generates a control signal; When the operating mode is locked, the field-programmable gate array locks the resonant wavelength by proportional, integral, and derivative methods to generate the control signal. The control signal is fed back to the coupled resonator optical waveguide filter so that the coupled resonator optical waveguide filter adjusts the output optical power based on the control signal.

2. The method according to claim 1, characterized in that, The step of injecting the laser output from the laser into the coupled resonator optical waveguide filter includes: The laser output from the laser is polarized by an input polarization controller. The laser output from the polarization controller is coupled to the grating coupler. The laser output from the grating coupler is injected into the optical waveguide filter of the coupled resonator.

3. The method according to claim 1, characterized in that, The steps for the coupled resonator optical waveguide filter to output optical power at its upper and lower ports respectively include: The upper port of the coupled resonator optical waveguide filter outputs a first proportion of optical power; The lower port of the coupled resonator optical waveguide filter outputs a second ratio of optical power; wherein the first ratio is greater than the second ratio.

4. The method according to claim 3, characterized in that, After the step of outputting a first proportion of optical power at the uplink port of the coupled resonator optical waveguide filter, the method further includes: The optical power output from the upper port is input to the spectrometer.

5. The method according to claim 1, characterized in that, The step of converting the optical power output from the downstream port into a digital electrical signal includes: The optical power output from the lower port is input to the photodetector, which outputs an electrical signal. The electrical signal is input to the transimpedance amplifier, and the amplified electrical signal is output. The amplified electrical signal is input into an analog-to-digital converter, and a digital electrical signal is output.

6. The method according to claim 1, characterized in that, The steps for switching the operating mode based on the thermal power and the digital electrical signal include: The maximum optical output power of the downstream port is determined based on the thermal power. If the ratio of the optical power represented by the digital electrical signal to the maximum optical output power is greater than or equal to a preset threshold, the working mode is determined to be a locked mode. If the ratio of the optical power represented by the digital electrical signal to the maximum optical output power is less than the threshold, the operating mode is determined to be a scanning mode.

7. The method according to claim 1, characterized in that, The step of feeding the control signal back to the coupled resonator optical waveguide filter includes: The control signal is input to the digital-to-analog converter, and the output is an analog control signal; The analog control signal is input to a low-noise amplifier and outputs a drive voltage. The driving voltage is fed back to the heater of the coupled resonator optical waveguide filter; The heater provides thermal tuning feedback to the microring resonator based on the driving voltage.

8. A wavelength locking device for a microring resonator, characterized in that, The coupled resonator optical waveguide filter incorporates multiple micro-ring resonators, and the device includes: An optical power output module is used to inject the laser output from the laser into the coupled resonator optical waveguide filter, wherein the upper and lower ports of the coupled resonator optical waveguide filter output optical power respectively. The digital electrical signal processing module is used to convert the optical power output from the downstream port into a digital electrical signal, and the digital electrical signal is input to a field-programmable gate array. The working mode switching module is used to scan the thermal power of the micro-ring resonator by the field-programmable gate array and switch the working mode based on the thermal power and the digital electrical signal. The scanning mode processing module is used to generate a control signal when the working mode is scanning mode, and the field programmable gate array adjusts the thermal power to track the target wavelength by iterative binary division. A locking mode processing module is used to generate the control signal when the working mode is locked mode, and the field programmable gate array locks the resonant wavelength by proportional, integral and derivative methods. A control signal feedback module is used to feed the control signal back to the coupled resonator optical waveguide filter so that the coupled resonator optical waveguide filter adjusts the output optical power based on the control signal.

9. An electronic device, characterized in that, The device includes a processor and a memory, the memory storing computer-executable instructions that can be executed by the processor, the processor executing the computer-executable instructions to implement the microring resonator wavelength locking method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when invoked and executed by a processor, cause the processor to implement the microring resonator wavelength locking method according to any one of claims 1 to 7.

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