A wavelength locking device, a wavelength locking method, and a communication apparatus

Abstract

This disclosure provides a wavelength locking device, a wavelength locking method, and a communication device. The wavelength locking device includes a first optical beamsplitter, a differential structure, and a control circuit connected in sequence. The first optical beamsplitter splits the modulated optical signal output from a micro-ring modulator into a test optical signal and an output optical signal. The differential structure includes a first optical path and a second optical path, wherein the transmission time of the second optical path is greater than the transmission time of the first optical path. The differential structure splits the test optical signal into a first optical signal and a second optical signal. After the first optical signal and the second optical signal are transmitted through the first optical path and the second optical path, respectively, they are combined into a third optical signal. The control circuit calculates the rate of change of the optical power of the third optical signal and controls the heating voltage of the thermal adjustment circuit in the micro-ring modulator according to the rate of change of the optical power of the third optical signal, so that the thermal adjustment circuit adjusts the resonant wavelength of the micro-ring modulator.

Description

Technical Field

[0001] This disclosure relates to the field of optical communication technology, and in particular to a wavelength locking device, wavelength locking method and communication equipment. Background Technology

[0002] In intelligent computing centers, as the scale of intelligent computing clusters continues to expand, communication distances also increase. Traditional electrical interconnection solutions are gradually becoming insufficient to meet the data transmission requirements of intelligent computing centers in terms of bandwidth, transmission distance, and energy density. Optical transmission, due to its advantages of low loss, low energy consumption, high bandwidth, and low latency, is considered a core technology for solving this problem. Currently, in-package optical I / O technology is booming, and its core transmitter structure consists of multiple micro-ring modulators (MRMs) connected in series on a single waveguide.

[0003] However, microring modulators are extremely sensitive to thermal disturbances and manufacturing errors, requiring wavelength locking. Commonly used wavelength locking methods in related technologies have some drawbacks, such as the locking point not being at the optimal operating state, or the required electrical signal processing burden being too large. Summary of the Invention

[0004] This disclosure provides a wavelength locking device, a wavelength locking method, and a communication device.

[0005] In a first aspect, embodiments of this disclosure provide a wavelength locking device, which is connected to a micro-ring modulator and includes a first optical beam splitter, a differential structure, and a control circuit connected in sequence.

[0006] The first optical beam splitter is used to receive the modulated optical signal output by the micro-ring modulator and split the modulated optical signal into a test optical signal and an output optical signal.

[0007] The differential structure includes a first optical path and a second optical path, wherein the transmission time of the second optical path is greater than the transmission time of the first optical path; the differential structure is used to receive the optical signal under test, split the optical signal under test into a first optical signal and a second optical signal, and after the first optical signal and the second optical signal are transmitted through the first optical path and the second optical path respectively, the first optical signal and the second optical signal are combined into a third optical signal;

[0008] The control circuit is used to receive the third optical signal, calculate the rate of change of the optical power of the third optical signal, and control the heating voltage of the thermal adjustment circuit in the micro-ring modulator according to the rate of change of the optical power of the third optical signal, so that the thermal adjustment circuit adjusts the resonant wavelength of the micro-ring modulator; the rate of change of the optical power of the third optical signal refers to the rate of change of the optical power of the third optical signal with the heating voltage.

[0009] In some embodiments, the control circuit is further configured to adjust the voltage value of the heating voltage to the voltage value corresponding to the maximum rate of change of the optical power of the third optical signal.

[0010] In some embodiments, the control circuit includes a photodetector and a control unit, wherein the photodetector is connected between the differential structure and the control unit;

[0011] The photodetector is used to receive the third optical signal and perform photoelectric conversion processing on the third optical signal to obtain a photocurrent signal;

[0012] The control unit is used to receive the photocurrent signal, calculate the rate of change of the photocurrent signal's optical power, and output a control signal based on the rate of change of the photocurrent signal's optical power. The control signal is used to control the thermal adjustment circuit.

[0013] In some embodiments, the photocurrent signal is an analog signal; the control circuit further includes an analog-to-digital converter circuit and a digital-to-analog converter circuit; the analog-to-digital converter circuit is connected between the photodetector and the control unit, and the digital-to-analog converter circuit is connected between the control unit and the thermal adjustment circuit;

[0014] The analog-to-digital conversion circuit is used to receive the photocurrent signal, perform analog-to-digital conversion on the photocurrent signal, and output it to the control unit; the control signal is a digital signal.

[0015] The digital-to-analog converter circuit is used to receive the control signal, convert the control signal into a digital signal and output it to the thermal adjustment circuit.

[0016] In some embodiments, the wavelength locking device further includes a first waveguide, and the microring modulator further includes a second waveguide, wherein the first waveguide and the second waveguide are coupled.

[0017] The first waveguide is used to receive an initial optical signal and to transmit the initial optical signal to the second waveguide based on the coupling between the first waveguide and the second waveguide;

[0018] The thermal adjustment circuit is used to heat the second waveguide based on the control of the control circuit;

[0019] The second waveguide is used to modulate the initial optical signal based on the heating of the thermal modulation circuit to obtain the modulated optical signal; and to transmit the modulated optical signal to the first waveguide based on the coupling between the first waveguide and the second waveguide.

[0020] The first waveguide is also used to transmit the modulated optical signal to the first optical beam splitter.

[0021] In some embodiments, the first optical path includes a third waveguide, the second optical path includes a tunable optical delay line, and the differential structure further includes a second optical beam splitter and an optical beam combiner.

[0022] The second optical beam splitter is used to receive the optical signal to be tested and split the optical signal to be tested into the first optical signal and the second optical signal;

[0023] The third waveguide is used to receive the first optical signal and transmit the first optical signal to the optical combiner.

[0024] The adjustable optical delay line is used to receive the second optical signal, delay the second optical signal, and transmit it to the optical combiner.

[0025] The optical combiner is used to receive the first optical signal and the second optical signal, combine the first optical signal and the second optical signal into the third optical signal, and output it.

[0026] In some embodiments, the optical power of the first optical signal and the second optical signal are equal.

[0027] In some embodiments, the differential structure is a Mach-Zehnder structure.

[0028] In a second aspect, embodiments of this disclosure provide a wavelength locking method, which is applied to a wavelength locking device as described in any one of the first aspects, the wavelength locking method comprising:

[0029] The modulated optical signal is split into a test optical signal and an output optical signal; wherein, the micro-ring modulator outputs the modulated optical signal;

[0030] The optical signal to be tested is split into a first optical signal and a second optical signal. After the first optical signal and the second optical signal are transmitted through the first optical path and the second optical path respectively, the first optical signal and the second optical signal are combined into a third optical signal. The transmission time corresponding to the second optical path is longer than the transmission time corresponding to the first optical path.

[0031] The rate of change of the optical power of the third optical signal is calculated, and the heating voltage is controlled according to the rate of change of the optical power of the third optical signal to adjust the resonant wavelength of the micro-ring modulator; the rate of change of the optical power of the third optical signal refers to the rate of change of the optical power of the third optical signal with the heating voltage.

[0032] Thirdly, embodiments of this disclosure provide a communication device, the communication device including a wavelength locking device as described in any one of the first aspects.

[0033] This disclosure provides a wavelength locking device, a wavelength locking method, and a communication device. The wavelength locking device is connected to a micro-ring modulator and includes a first optical beamsplitter, a differential structure, and a control circuit connected in sequence. The first optical beamsplitter receives the modulated optical signal output from the micro-ring modulator and splits the modulated optical signal into a test optical signal and an output optical signal. The differential structure includes a first optical path and a second optical path, wherein the transmission time of the second optical path is greater than the transmission time of the first optical path. The differential structure receives the test optical signal, splits the test optical signal into a first optical signal and a second optical signal, and after the first optical signal and the second optical signal are transmitted through the first optical path and the second optical path respectively, they are combined into a third optical signal. The control circuit receives the third optical signal, calculates the rate of change of the optical power of the third optical signal, and controls the heating voltage of the thermal adjustment circuit in the micro-ring modulator according to the rate of change of the optical power of the third optical signal, so that the thermal adjustment circuit adjusts the resonant wavelength of the micro-ring modulator. The rate of change of the optical power of the third optical signal refers to the rate of change of the optical power of the third optical signal with the heating voltage. In this way, by using the first and second optical paths with different transmission times, differential processing of the preceding and following symbols in the optical signal under test is achieved, resulting in a third optical signal. The resonant wavelength of the micro-ring modulator is then adjusted based on the rate of change of the optical power of the third optical signal. This wavelength locking device can lock the resonant wavelength of the micro-ring modulator to its optimal operating point. Furthermore, this wavelength locking device is simple to operate, has low electrical load, low power consumption, and can be integrated on a single chip. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the composition structure of a wavelength locking device provided in an embodiment of the present disclosure;

[0035] Figure 2 This is a schematic diagram of the composition of a differential structure provided in an embodiment of the present disclosure;

[0036] Figure 3 A signal simulation diagram of a wavelength locking device provided in this disclosure embodiment. Figure 1 ;

[0037] Figure 4A signal simulation diagram of a wavelength locking device provided in this disclosure embodiment. Figure 2 ;

[0038] Figure 5 A schematic flowchart of a wavelength locking method provided in an embodiment of this disclosure;

[0039] Figure 6 This is a schematic diagram of the composition structure of a communication device provided in an embodiment of this disclosure. Detailed Implementation

[0040] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the disclosure. Furthermore, it should be noted that, for ease of description, only the parts relevant to the disclosure are shown in the accompanying drawings.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing embodiments of this disclosure only and is not intended to be limiting of this disclosure.

[0042] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0043] It should be noted that the terms "first, second, third" used in the embodiments of this disclosure are merely to distinguish similar objects and do not represent a specific ordering of objects. It is understood that "first, second, third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this disclosure described herein can be implemented in an order other than that illustrated or described herein.

[0044] Artificial intelligence (AI) models are developing rapidly and have already demonstrated near-human intelligence in several fields (such as mathematics, programming, vision, medicine, law, and psychology). However, this intelligence requires extremely large amounts of computing power as a foundation. According to publicly available data, the famous GPT-4 model has 1.8 trillion parameters and requires 25,000 graphics processing units (GPUs) to train it for 90 to 100 days.

[0045] Currently, the demand for computing power for large-scale AI models being developed by academia and industry is increasing by approximately 750 times per year. However, limited by Moore's Law and the quantum tunneling effect, the computing power growth rate of a single AI chip is only 2 times per year, and the growth rate is slowing down. To resolve the contradiction between computing power demand and supply, intelligent computing centers have to use a large number of GPUs and memory chips to form computing clusters to meet the data storage and computing needs of large-scale AI models.

[0046] It's important to note that in intelligent computing centers, simply stacking GPUs is insufficient for effective computation. Intelligent computing clusters must be able to efficiently and flexibly allocate tasks dynamically between data processing and data storage units, which necessitates a large volume of low-latency, high-bandwidth data transmission. Optical transmission, due to its advantages of low loss, low energy consumption, high bandwidth, and low latency, has gradually expanded from long-distance communication to data centers, between server boards, and even between and on-chip data interconnects.

[0047] Because intelligent computing centers and AI computing are more sensitive to communication density and energy consumption, an in-package optical I / O technology is rapidly emerging. This technology refers to the XPU chip ("X" stands for unknown and specific domain, and "XPU" stands for different types of processors) interface directly converting signals into optical signals for off-chip data transmission via electro-optic conversion. Its core transmitter structure consists of multiple micro-ring modulators connected in series on a single waveguide. Utilizing the filtering and modulation characteristics of the micro-rings, multiple wavelengths can be modulated and data loaded within a very small area.

[0048] However, microring modulators are extremely sensitive to thermal disturbances and manufacturing errors, typically requiring an automatic wavelength locking feedback mechanism. Common wavelength locking methods include: monitoring the optical power of the modulated signal and adjusting the thermally adjustable bias voltage of the microring modulator to maintain the minimum output optical power or the fastest change in optical power; or, acquiring the modulated signal at high speed and using mixed-signal circuits and processing algorithms to maintain the optimal modulation state through the thermally adjustable bias voltage of the microring modulator. However, these methods may have drawbacks such as the locking point not being the optimal operating state, or the required electrical signal processing burden being too large; the locking point of a microring modulator refers to the operating point where the microring modulator achieves the best modulation effect under specific conditions.

[0049] Based on this, the present disclosure provides a wavelength locking device connected to a micro-ring modulator. The wavelength locking device includes a first optical beamsplitter, a differential structure, and a control circuit connected in sequence. The first optical beamsplitter is used to receive the modulated optical signal output from the micro-ring modulator and split the modulated optical signal into a test optical signal and an output optical signal. The differential structure includes a first optical path and a second optical path, wherein the transmission time of the second optical path is greater than the transmission time of the first optical path. The differential structure is used to receive the test optical signal, split the test optical signal into a first optical signal and a second optical signal, and after the first optical signal and the second optical signal are transmitted through the first optical path and the second optical path respectively, combine the first optical signal and the second optical signal into a third optical signal. The control circuit is used to receive the third optical signal, calculate the rate of change of the optical power of the third optical signal, and control the heating voltage of the thermal adjustment circuit in the micro-ring modulator according to the rate of change of the optical power of the third optical signal, so that the thermal adjustment circuit adjusts the resonant wavelength of the micro-ring modulator. The rate of change of the optical power of the third optical signal refers to the rate of change of the optical power of the third optical signal with the heating voltage. In this way, by using the first and second optical paths with different transmission times, differential processing of the preceding and following symbols in the optical signal under test is achieved, resulting in a third optical signal. The resonant wavelength of the micro-ring modulator is then adjusted based on the rate of change of the optical power of the third optical signal. This wavelength locking device can lock the resonant wavelength of the micro-ring modulator to its optimal operating point. Furthermore, this wavelength locking device is simple to operate, has low electrical load, low power consumption, and can be integrated on a single chip.

[0050] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0051] In one embodiment of this disclosure, see [link to embodiment]. Figure 1 This illustration shows a schematic diagram of the composition structure of a wavelength locking device provided in an embodiment of this disclosure. Figure 1 As shown, the wavelength locking device 10 (not shown) is connected to the micro-ring modulator 20. The wavelength locking device 10 includes a first optical beam splitter 11, a differential structure 12 and a control circuit 13 connected in sequence.

[0052] The first optical beam splitter 11 is used to receive the modulated optical signal output by the micro-ring modulator 20 and split the modulated optical signal into a test optical signal and an output optical signal.

[0053] The differential structure 12 may include a first optical path 121 and a second optical path 122, wherein the transmission time of the second optical path 122 is greater than the transmission time of the first optical path 121; the differential structure 12 is used to receive the optical signal to be tested, split the optical signal to be tested into a first optical signal and a second optical signal, and after the first optical signal and the second optical signal are transmitted through the first optical path 121 and the second optical path 122 respectively, the first optical signal and the second optical signal are combined into a third optical signal;

[0054] The control circuit 13 is used to receive the third optical signal, calculate the rate of change of the optical power of the third optical signal, and control the heating voltage of the heat adjustment circuit 21 in the micro-ring modulator 20 according to the rate of change of the optical power of the third optical signal, so that the heat adjustment circuit 21 adjusts the resonant wavelength of the micro-ring modulator 20; the rate of change of the optical power of the third optical signal refers to the rate of change of the optical power of the third optical signal with the heating voltage.

[0055] Here, the rate of change of optical power refers to the rate of change of optical power, specifically the rate of change of optical power with heating voltage.

[0056] It should be noted that the embodiments disclosed herein belong to the field of optical communication and optical computing technology. The wavelength locking device 10 is specifically an optoelectronic system based on an optical Mach-Zehnder (also known as Mach-Zehnder) structure for automatic wavelength locking of micro-ring modulators.

[0057] The micro-ring modulator primarily achieves the encoding and control of optical signals by modulating the light waves within the micro-ring. Automatic wavelength locking in the micro-ring modulator refers to maintaining the resonant wavelength of the micro-ring modulator near a set target wavelength. Because micro-ring modulators are susceptible to environmental factors and have unstable refractive indices, leading to unstable resonant wavelengths, control of the resonant wavelength is necessary.

[0058] It should also be noted that the first optical beamsplitter 11 is specifically an optical power beamsplitter, used to split the modulated optical signal into two optical signals: a test optical signal and an output optical signal. The test optical signal is used to monitor and control the micro-ring modulator 20; the output optical signal is used to transmit data so that the receiving end can receive the output optical signal. Furthermore, the optical power ratio between the test optical signal and the output optical signal can be 5:5, 1:9, or other ratios, etc., without specific limitation. Preferably, a smaller portion of the modulated optical signal is split as the test optical signal, for example, the optical power ratio between the test optical signal and the output optical signal is 1:9.

[0059] It should also be noted that the differential structure 12 can realize differential processing between signal symbols in the optical signal under test. Here, a symbol is the basic signal unit carrying information. In digital communication, a symbol is represented by a symbol with the same time interval. For example, there are sequences: [0110110010011101101] and [02301000332001123]. When transmitting digital signals, each finite value in the above sequences (e.g., 0 or 1 in the first sequence, 0, 1, 2, or 3 in the second sequence) is called a symbol.

[0060] In this embodiment, a first optical signal and a second optical signal with different transmission times are transmitted through a first optical path 121 and a second optical path 122 in the differential structure 12, respectively. The transmission time corresponding to the second optical path 122 is greater than the transmission time corresponding to the first optical path 121, meaning that the second optical signal is delayed. Then, the first and second optical signals after transmission through the optical paths are combined into a third optical signal for output, thus realizing differential processing of preceding and following symbols. It can be understood that differential processing of preceding and following symbols refers to comparing the current symbol with its preceding symbol and generating a new symbol sequence based on their differences.

[0061] In some embodiments, the differential structure 12 can be a Mach-Zehnder structure.

[0062] It should be noted that the differential structure 12 can specifically be a Mach-Zehnder Interferometer (MZI) structure.

[0063] It should also be noted that the control circuit 13 generates a control signal, which, after digital-to-analog conversion, generates an analog voltage signal, which is the heating voltage, also known as the thermally adjustable bias voltage. This embodiment employs a photoelectric hybrid feedback control structure, utilizing the differential structure 12 to achieve differential processing between consecutive symbols in the optical signal under test, obtaining a third optical signal. The control circuit 13 monitors the optical power of the third optical signal, tracking the change in optical power with the thermally adjustable bias voltage in the micro-ring modulator 20, thereby locking the resonant wavelength of the micro-ring modulator 20 to the optimal operating point.

[0064] This disclosure provides a method for differential processing of consecutive symbols in a measured optical signal based on a Mach-Zehnder structure, and for obtaining the photoelectric structure of the thermally modulated bias in the locked micro-ring modulator 20 based on the differential signal (i.e., the third optical signal). This wavelength locking device 10 can be integrated on-chip, performs differential processing between signal symbols at the speed of light using extremely low power consumption, and its control circuit 13 has simple processing requirements and low electrical burden.

[0065] In this embodiment of the disclosure, after obtaining the rate of change of the optical power of the third optical signal with the heating voltage, the rate of change of the optical power of the maximum third optical signal is determined.

[0066] In some embodiments, the control circuit 13 is further configured to adjust the heating voltage to the voltage value that maximizes the rate of change of the optical power of the third optical signal.

[0067] It should be noted that the thermal adjustment circuit 21 may include a resistor. The resistor generates different amounts of heat under different heating voltage values, thus causing the temperature across the resistor to change. Here, the resistor can specifically be a heating resistor, or a thermally adjustable resistor. The control circuit 13 analyzes the change in the optical power of the current third optical signal and adjusts the heating voltage to the value corresponding to the point where the optical power of the third optical signal changes most rapidly, thereby determining the heating voltage and controlling the resonant wavelength of the micro-ring modulator 20.

[0068] It should be noted that the control circuit 13 in the wavelength locking device 10 calculates the change in current optical power with heating voltage, and obtains the heating voltage corresponding to the maximum change in optical power. For details, please refer to the following sections. Figures 3 to 4 And understand the related descriptions.

[0069] In some embodiments, such as Figure 1 As shown, the control circuit 13 may include a photodetector 131 and a control unit 132, with the photodetector 131 connected between the differential structure 12 and the control unit 132.

[0070] Photodetector 131 is used to receive the third optical signal and perform photoelectric conversion processing on the third optical signal to obtain a photocurrent signal;

[0071] The control unit 132 is used to receive the photocurrent signal, calculate the rate of change of the photocurrent signal's optical power, and output a control signal based on the rate of change of the photocurrent signal's optical power. The control signal is used to control the thermal adjustment circuit 21.

[0072] Here, the rate of change of the optical power of the photocurrent signal specifically refers to the rate of change of the optical power of the photocurrent signal with the heating voltage.

[0073] In some embodiments, such as Figure 1 As shown, the photoelectric detector (PD) 131 may include a photodiode a1, but is not specifically limited thereto.

[0074] It should be noted that the control unit 132 can specifically be a microcontroller unit (MCU), without specific limitations. The control signal can also be called a thermal modulation signal. The control unit 132 is used to analyze the trend of optical power variation of the differential signal (i.e., the third optical signal) with the thermal modulation signal and to give instructions on the magnitude of the thermal modulation signal. Because the control unit 132 analyzes electrical signals, the third optical signal needs to be converted into a photocurrent signal by the photodetector 131 for analysis first.

[0075] It should also be noted that the rate of change of optical power can be calculated by the control unit 132, or by other devices, such as an optical power meter; however, this will not be specifically described here. Exemplarily, the specific implementation of the embodiments of this disclosure will be described in detail using the calculation of the rate of change of optical power by the control unit 132 as an example.

[0076] In some embodiments, the photocurrent signal is an analog signal, and the control signal is a digital signal; such as Figure 1 As shown, the control circuit 13 may also include a conversion circuit;

[0077] The conversion circuit is used to receive the photocurrent signal, perform analog-to-digital conversion on the photocurrent signal, and output it to the control unit 132; and to receive the control signal, perform digital-to-analog conversion on the control signal, and output it to the thermal adjustment circuit 21.

[0078] It should be noted that the conversion circuit can also be called a signal conditioning circuit. The signal conditioning circuit is used to sample the photocurrent, convert the current corresponding to the third optical signal into a signal that can be read by the control unit 132, and the current corresponding to different optical powers of the third optical signal is also different; and to convert the output command (i.e. the control signal) of the control unit 132 into an electrical signal that can be received by the thermal adjustment circuit 21.

[0079] Specifically, in some embodiments, such as Figure 1 As shown, the conversion circuit may also include an analog-to-digital converter circuit 133 and a digital-to-analog converter circuit 134; the analog-to-digital converter circuit 133 is connected between the photodetector 131 and the control unit 132, and the digital-to-analog converter circuit 134 is connected between the control unit 132 and the thermal adjustment circuit 21.

[0080] The analog-to-digital conversion circuit 133 is used to receive the photocurrent signal, perform analog-to-digital conversion on the photocurrent signal, and output it to the control unit 132.

[0081] The digital-to-analog converter circuit 134 is used to receive control signals, convert the control signals into digital signals and output them to the thermal adjustment circuit 21.

[0082] It should be noted that the analog-to-digital conversion circuit 133 may include an analog-to-digital converter (ADC), which is an electronic device that converts analog signals into digital signals; the digital-to-analog conversion circuit 134 may include a digital-to-analog converter (DAC), which is an electronic device that converts digital signals into analog signals.

[0083] It should also be noted that after the control signal is converted from digital to analog, it will output a heating voltage to the thermal adjustment circuit 21. In other words, the thermal adjustment circuit 21 receives the heating voltage, and the control signal is used to control the thermal adjustment circuit 21 so that the thermal adjustment circuit 21 adjusts the resonant wavelength of the micro-ring modulator 20.

[0084] In this embodiment, the electrical signal (i.e., the photocurrent signal) is converted from analog to digital by the analog-to-digital converter circuit 133, and then the control unit 132 performs numerical analysis. After the control unit 132 outputs a control signal, it controls the resistor through the digital-to-analog converter circuit 134, ultimately controlling the resonant wavelength of the micro-ring modulator 20. The electrical monitoring circuit (i.e., the control circuit 13) monitors the rate of change of the optical power of the third optical signal. Compared with the monitoring circuits in related technologies, its operation is simpler and does not increase the burden of additional integrated circuit design and power consumption.

[0085] In some embodiments, such as Figure 1 As shown, the wavelength locking device 10 may further include a first waveguide 14, and the micro-ring modulator 20 may further include a second waveguide 22, with the first waveguide 14 and the second waveguide 22 coupled together.

[0086] The first waveguide 14 is used to receive the initial optical signal and transmit the initial optical signal to the second waveguide 22 based on the coupling between the first waveguide 14 and the second waveguide 22.

[0087] Thermal control circuit 21 is used to heat the second waveguide 22 based on the control of control circuit 13;

[0088] The second waveguide 22 is used to modulate the initial optical signal based on the heating of the thermal modulation circuit 21 to obtain a modulated optical signal; and to transmit the modulated optical signal to the first waveguide 14 based on the coupling between the first waveguide 14 and the second waveguide 22.

[0089] The first waveguide 14 is also used to transmit the modulated optical signal to the first optical beam splitter 11.

[0090] It should be noted that the initial optical signal enters the second waveguide 22 coupled to it through the first waveguide 14. After the initial optical signal is modulated in the second waveguide 22, it is then transmitted to the first optical beam splitter 11 through the first waveguide 14.

[0091] It should also be noted that the microring modulator utilizes a microring structure to modulate optical signals. Its working principle is based on electro-optic, thermo-optic, or mechanical effects, adjusting the intensity, phase, or frequency of the optical signal passing through the microring by changing the refractive index of the material. In this embodiment, the heating voltage changes, thus changing the temperature across the resistor in the thermally adjustable circuit 21, thereby altering the refractive index of the second waveguide 22 and adjusting the resonant wavelength of the microring modulator 20.

[0092] In addition, the thermally modulated circuit 21 and the second waveguide 22 in the micro-ring modulator 20 are located in different signal layers and are coupled to each other.

[0093] In some embodiments, such as Figure 2 As shown, in the differential structure 12, the first optical path 121 may include a third waveguide b1, the second optical path 122 may include an adjustable optical delay line b2, and the differential structure 12 may also include a second optical beam splitter 123 and an optical beam combiner 124.

[0094] The second optical beam splitter 123 is used to receive the optical signal to be tested and split the optical signal to be tested into a first optical signal and a second optical signal.

[0095] The third waveguide b1 is used to receive the first optical signal and transmit the first optical signal to the optical combiner 124;

[0096] The tunable optical delay line b2 is used to receive the second optical signal, delay the second optical signal, and transmit it to the optical combiner 124.

[0097] The optical combiner 124 is used to receive the first optical signal and the second optical signal, combine the first optical signal and the second optical signal into a third optical signal and output it.

[0098] It should be noted that the differential structure 12 can specifically be an MZI structure, which is a passive device that can perform differential processing of the preceding and following symbols in the optical signal under test with extremely low power consumption.

[0099] It should also be noted that the traditional MZI structure includes two waveguides. In this embodiment, one of the waveguides is replaced with an adjustable optical delay line b2, thereby delaying the second optical signal so that the third optical signal obtained after beam combining is a differential optical signal.

[0100] In some embodiments, the optical power of the first optical signal and the second optical signal is equal.

[0101] In other words, the ratio of the optical power of the first optical signal to the second optical signal is 5:5. The second optical beam splitter 123 can specifically be a 50:50 beam splitter, which is used to split the optical signal to be tested into a first optical signal and a second optical signal with equal power.

[0102] Based on the wavelength locking device 10 described above, see... Figure 3 It illustrates a signal simulation diagram of a wavelength locking device provided in an embodiment of this disclosure. Figure 1 .exist Figure 3In the diagram, the solid line represents the transmission spectrum of the micro-ring modulator 20, the dashed line represents the curve of the optical power of the third optical signal changing with the thermally tuned bias voltage, and the dotted line represents the curve of the third optical signal changing with the thermally tuned bias voltage. The horizontal axis of all three curves is the thermally tuned bias voltage, in atomic units (au). The vertical axis of the solid line is the transmittance of the micro-ring modulator 20, in au; the vertical axis of the dashed line is the normalized differential optical power (norm.substraction), in au; and the vertical axis of the dotted line is the normalized rate of change of optical power (norm.substraction slope), in au. In essence, differential optical power refers to the optical power of the third optical signal, and the vertical axis of the dotted line specifically represents the rate of change of differential optical power; that is, the vertical axis of the dotted line is the slope of the vertical axis of the dashed line.

[0103] It should be noted that on the dashed line, points ① and ⑤ represent the points with the lowest optical power of the third optical signal, and point ③ represents the point with the highest optical power of the third optical signal; on the dotted line, points ② and ④ represent the points with the fastest changes in the optical power of the third optical signal. Specifically, point ② represents the point with the fastest increase in the optical power of the third optical signal, and point ④ represents the point with the fastest decrease in the optical power of the third optical signal.

[0104] It should also be noted that the lowest point of the solid line corresponds to the highest point of the dashed line. In other words, the minimum transmittance of the micro-ring modulator 20 corresponds to the maximum value of the differential optical power of the normalized modulation signal.

[0105] See Figure 4 It illustrates a signal simulation diagram of a wavelength locking device provided in an embodiment of this disclosure. Figure 2 .in, Figure 4 (a), (c), and (e) in the figure are points ①, ③, and ⑤, respectively, which are the modulation signal eye diagrams after the thermally tuned bias-locked micro-ring modulator 20 when the optical power is at its minimum, maximum, and minimum. Figure 4 In the diagram, (b) and (d) are points ② and ④, respectively, which are the modulation signal eye diagrams after the thermally modulated bias-locked micro-ring modulator 20 when the optical power changes the fastest.

[0106] It's important to note that an eye diagram is a graphical representation of a series of digital signals accumulated on an oscilloscope. It contains a wealth of information, allowing observation of intersymbol interference (ISI) and noise, reflecting the overall characteristics of the digital signal, and thus estimating the system's performance. The size of the "eyes" in the eye diagram reflects the strength of ISI. Larger "eyes" and a more upright eye diagram indicate less ISI; conversely, smaller "eyes" indicate greater ISI.

[0107] like Figure 4 As shown, Figure 4 The eye diagrams (a), (c), and (e) in the diagram are of poor quality and cannot be used to modulate signals; Figure 4 In diagrams (b) and (d), the large "eyes" indicate effective modulation signals. In other words, the point where the optical power of the third optical signal changes most rapidly is the optimal operating point.

[0108] It should also be noted that the modulation signal of the micro-ring modulator 20 is a high-speed signal, and the eye diagram of the high-speed signal is related to and affected by the aforementioned control signal.

[0109] This embodiment of the disclosure provides a wavelength locking device 10. A first optical beamsplitter 11 inputs a portion of the modulated optical signal (i.e., the optical signal to be measured) to a feedback loop (i.e., a loop composed of the first optical beamsplitter 11, a differential structure 12, and a control circuit 13) for monitoring a micro-ring modulator 20. A second optical beamsplitter 123 splits the optical signal to be measured into two optical signals of equal power (i.e., the first optical signal and the second optical signal). One of the optical signals (i.e., the second optical signal) undergoes a time delay via an adjustable optical delay line b2. When it is transmitted to an optical combiner 124, the symbol positions of the two optical signals are staggered. After beam combining, differential processing of the preceding and following symbols can be achieved to obtain a third optical signal. The third optical signal undergoes photoelectric conversion via a photodetector 131. The obtained photocurrent signal undergoes analog-to-digital sampling via an analog-to-digital converter 133 and is numerically analyzed via a control unit 132. The control signal output by the control unit 132 controls the resistor via a digital-to-analog converter 134, ultimately controlling the resonant wavelength of the micro-ring modulator 20. The control unit 132 analyzes the rate of change of the optical power of the current third optical signal and adjusts the heating voltage to the voltage value corresponding to the point where the optical power of the third optical signal changes the fastest. The point where the optical power of the third optical signal changes the fastest is the optimal operating point. The wavelength locking device 10 can lock the resonant wavelength of the micro-ring modulator 20 to the optimal operating point. The wavelength locking device 10 is simple to operate, has low electrical burden, low power consumption, and can be integrated on a chip.

[0110] In another embodiment of this disclosure, see Figure 5 This illustration shows a flowchart of a wavelength locking method provided in an embodiment of this disclosure. Figure 5 As shown, the wavelength locking method may include:

[0111] S301. The modulated optical signal is split into a test optical signal and an output optical signal; wherein, the micro-ring modulator outputs the modulated optical signal.

[0112] S302. The optical signal to be tested is split into a first optical signal and a second optical signal. After the first optical signal and the second optical signal are transmitted through the first optical path and the second optical path respectively, the first optical signal and the second optical signal are combined into a third optical signal. The transmission time corresponding to the second optical path is longer than the transmission time corresponding to the first optical path.

[0113] S303. Calculate the rate of change of the optical power of the third optical signal, and control the heating voltage according to the rate of change of the optical power of the third optical signal to adjust the resonant wavelength of the micro-ring modulator; the rate of change of the optical power of the third optical signal refers to the rate of change of the optical power of the third optical signal with the heating voltage.

[0114] It should be noted that the wavelength locking method provided in this disclosure can be applied to the wavelength locking device 10 described in the foregoing embodiments.

[0115] In some embodiments, the wavelength locking method may further include:

[0116] The third optical signal is processed by photoelectric conversion to obtain a photocurrent signal;

[0117] The rate of change of optical power in the photocurrent signal is calculated, and a control signal is output based on the rate of change of optical power in the photocurrent signal. The control signal is used to control the thermal adjustment circuit.

[0118] In some embodiments, the photocurrent signal is an analog signal and the control signal is a digital signal; the wavelength locking method may further include:

[0119] Analog-to-digital conversion is performed on the photocurrent signal;

[0120] The control signal is converted from digital to analog.

[0121] This disclosure provides a wavelength locking method. Based on a first optical path and a second optical path with different transmission times, differential processing of consecutive symbols in the optical signal under test is achieved to obtain a third optical signal. The resonant wavelength of the micro-ring modulator is adjusted according to the rate of change of the optical power of the third optical signal to lock the resonant wavelength of the micro-ring modulator to the optimal operating point.

[0122] In another embodiment of this disclosure, see [reference needed]. Figure 6 This illustration shows a schematic diagram of the composition structure of a communication device provided in an embodiment of this disclosure. Figure 6 As shown, the communication device 40 may include the aforementioned wavelength locking device 10.

[0123] Here, the communication equipment can specifically be an optical communication device, which refers to a communication device that uses light waves to transmit information. This disclosure does not limit the specific type of communication equipment.

[0124] In this embodiment of the disclosure, the communication device 40, since it includes the aforementioned wavelength locking device 10, has at least the same advantages as the wavelength locking device 10, which can lock the resonant wavelength of the micro-ring modulator 20 to the optimal operating point, and has low electrical burden and low power consumption.

[0125] For details not disclosed in the embodiments of this disclosure, please refer to the description of the foregoing embodiments for understanding.

[0126] The above description is merely a preferred embodiment of this disclosure and is not intended to limit the scope of protection of this disclosure.

[0127] It should be noted that, in this disclosure, 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 limitation, 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 that element.

[0128] The sequence numbers of the embodiments disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0129] The methods disclosed in the several method embodiments provided in this disclosure can be arbitrarily combined without conflict to obtain new method embodiments.

[0130] The features disclosed in the several product embodiments provided in this disclosure can be combined arbitrarily without conflict to obtain new product embodiments.

[0131] The features disclosed in the several method or device embodiments provided in this disclosure can be arbitrarily combined without conflict to obtain new method or device embodiments.

[0132] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A wavelength locking device, characterized in that, The wavelength locking device is connected to the micro-ring modulator, and the wavelength locking device includes a first optical beam splitter, a differential structure, and a control circuit connected in sequence. The first optical beam splitter is used to receive the modulated optical signal output by the micro-ring modulator and split the modulated optical signal into a test optical signal and an output optical signal. The differential structure includes a first optical path and a second optical path, wherein the transmission time of the second optical path is greater than the transmission time of the first optical path; the differential structure is used to receive the optical signal under test, split the optical signal under test into a first optical signal and a second optical signal, and after the first optical signal and the second optical signal are transmitted through the first optical path and the second optical path respectively, the first optical signal and the second optical signal are combined into a third optical signal; The control circuit is used to receive the third optical signal, calculate the rate of change of the optical power of the third optical signal, and control the heating voltage of the thermal adjustment circuit in the micro-ring modulator according to the rate of change of the optical power of the third optical signal, so that the thermal adjustment circuit adjusts the resonant wavelength of the micro-ring modulator; the rate of change of the optical power of the third optical signal refers to the rate of change of the optical power of the third optical signal with the heating voltage.

2. The wavelength locking device according to claim 1, characterized in that, The control circuit is also used to adjust the voltage value of the heating voltage to the voltage value corresponding to the maximum rate of change of the optical power of the third optical signal.

3. The wavelength locking device according to claim 1, characterized in that, The control circuit includes a photodetector and a control unit, wherein the photodetector is connected between the differential structure and the control unit; The photodetector is used to receive the third optical signal and perform photoelectric conversion processing on the third optical signal to obtain a photocurrent signal; The control unit is used to receive the photocurrent signal, calculate the rate of change of the photocurrent signal's optical power, and output a control signal based on the rate of change of the photocurrent signal's optical power. The control signal is used to control the thermal adjustment circuit.

4. The wavelength locking device according to claim 3, characterized in that, The photocurrent signal is an analog signal; the control circuit further includes an analog-to-digital converter circuit and a digital-to-analog converter circuit; the analog-to-digital converter circuit is connected between the photodetector and the control unit, and the digital-to-analog converter circuit is connected between the control unit and the thermal adjustment circuit; The analog-to-digital conversion circuit is used to receive the photocurrent signal, perform analog-to-digital conversion on the photocurrent signal, and output it to the control unit; the control signal is a digital signal. The digital-to-analog converter circuit is used to receive the control signal, convert the control signal into a digital signal and output it to the thermal adjustment circuit.

5. The wavelength locking device according to claim 1, characterized in that, The wavelength locking device further includes a first waveguide, and the micro-ring modulator further includes a second waveguide, wherein the first waveguide and the second waveguide are coupled. The first waveguide is used to receive an initial optical signal and to transmit the initial optical signal to the second waveguide based on the coupling between the first waveguide and the second waveguide; The thermal adjustment circuit is used to heat the second waveguide based on the control of the control circuit; The second waveguide is used to modulate the initial optical signal based on the heating of the thermal modulation circuit to obtain the modulated optical signal; and to transmit the modulated optical signal to the first waveguide based on the coupling between the first waveguide and the second waveguide. The first waveguide is also used to transmit the modulated optical signal to the first optical beam splitter.

6. The wavelength locking device according to claim 1, characterized in that, The first optical path includes a third waveguide, the second optical path includes a tunable optical delay line, and the differential structure further includes a second optical beam splitter and an optical beam combiner; The second optical beam splitter is used to receive the optical signal to be tested and split the optical signal to be tested into the first optical signal and the second optical signal; The third waveguide is used to receive the first optical signal and transmit the first optical signal to the optical combiner. The adjustable optical delay line is used to receive the second optical signal, delay the second optical signal, and transmit it to the optical combiner. The optical combiner is used to receive the first optical signal and the second optical signal, combine the first optical signal and the second optical signal into the third optical signal, and output it.

7. The wavelength locking device according to claim 6, characterized in that, The optical power of the first optical signal and the second optical signal are equal.

8. The wavelength locking device according to any one of claims 1 to 7, characterized in that, The differential structure is a Mach-Zehnder structure.

9. A wavelength locking method, characterized in that, The wavelength locking method is applied to the wavelength locking device as described in any one of claims 1 to 8, the wavelength locking method comprising: The modulated optical signal is split into a test optical signal and an output optical signal; wherein, the micro-ring modulator outputs the modulated optical signal; The optical signal to be tested is split into a first optical signal and a second optical signal. After the first optical signal and the second optical signal are transmitted through the first optical path and the second optical path respectively, the first optical signal and the second optical signal are combined into a third optical signal. The transmission time corresponding to the second optical path is longer than the transmission time corresponding to the first optical path. The rate of change of the optical power of the third optical signal is calculated, and the heating voltage is controlled according to the rate of change of the optical power of the third optical signal to adjust the resonant wavelength of the micro-ring modulator; the rate of change of the optical power of the third optical signal refers to the rate of change of the optical power of the third optical signal with the heating voltage.

10. A communication device, characterized in that, The communication device includes a wavelength locking device as described in any one of claims 1 to 8.

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