Wavelength calibration method and apparatus

Abstract

This application provides a wavelength calibration method and apparatus, comprising: acquiring a reference optical signal; adjusting the output wavelength of a local laser according to the reference optical signal to generate a reference optical signal, wherein the reference optical signal has the same wavelength as the reference optical signal; generating multiple target optical signals based on the reference optical signal, wherein each target optical signal has a different wavelength and the frequency difference between each target optical signal and the reference optical signal is different and fixed; and extracting a first target optical signal from the multiple target optical signals for data transmission. This wavelength calibration method ensures that the optical signal transmitting data is synchronized with the reference optical signal, thereby ensuring that the wavelengths of data transmitted by all nodes in the entire network are synchronized.

Description

Technical Field

[0001] This application relates to the field of optical communications, and more specifically, to a wavelength calibration method and apparatus. Background Technology

[0002] With the continuous development of optical communication systems, fiber optic networks face the dual requirements of high bandwidth and flexibility / intelligence. Currently, wavelength division multiplexing (WDM) technology using a fixed grid results in excessively low spectral utilization. Therefore, introducing a flexible grid allows signals from different network nodes to be closely aligned spectrally, thereby maximizing spectral utilization.

[0003] However, in flexible grid deployments, signal impairments such as crosstalk limit the setting of the minimum guard bandgap between spectra. Since the lasers at different optical network nodes in a fiber optic network are independent and have high random frequency differences, spectral aliasing is inevitable, leading to signal quality degradation and other problems.

[0004] Therefore, ensuring stable frequency differences between optical network nodes to improve network spectrum utilization efficiency is an urgent problem to be solved. Summary of the Invention

[0005] This application provides a wavelength calibration method and apparatus that can ensure stable frequency errors in optical network nodes, thereby improving network spectrum utilization efficiency.

[0006] In a first aspect, a wavelength calibration method is provided, comprising: acquiring a reference optical signal; adjusting the output wavelength of a local laser according to the reference optical signal to generate a reference optical signal, wherein the reference optical signal has the same wavelength as the reference optical signal; generating multiple target optical signals based on the reference optical signal, wherein each target optical signal has a different wavelength and the frequency difference between each target optical signal and the reference optical signal is different and fixed; and extracting a first target optical signal from the multiple target optical signals for data transmission.

[0007] According to the scheme provided in this application, a reference light is acquired, and a reference light is generated based on the reference light. Then, a first target optical signal with a stable frequency difference from the reference light is generated for loading data during its own operation. This method is applicable to all network nodes in the system. By using a unified wavelength reference for wavelength calibration, it can ensure that the optical network nodes have stable frequency errors. This reduces the guard bandgap when the network adopts a flexible grid deployment, improves the network spectrum utilization efficiency, and thus ensures the signal transmission quality.

[0008] The technical solution presented in this application is applied to flexible optical networks, such as multi-level ring network structures. After wavelength calibration across the entire network, the spectral spacing of laser wavelengths between network nodes is stable, thus avoiding spectral aliasing caused by random laser frequency differences. Therefore, guard band spacing between spectra can be eliminated, improving spectral utilization. Compared to traditional optical networks, all-optical networks offer greater flexibility, transparency, compatibility, and scalability. Furthermore, while ensuring wavelength synchronization, signal add / drop and sub-band optical switching at each network node can be flexibly implemented.

[0009] It should be noted that the reference optical signal and the base optical signal have the same wavelength. Due to signal distortion or path loss differences, in order to ensure the current network node... X Mid-wavelength calibration and signal transmission quality require adjusting the wavelength of the local laser based on the reference light to obtain a reference light with high signal quality, so as to realize the subsequent wavelength calibration mechanism.

[0010] For example, the reference optical signal may refer to a continuous DC optical signal with a wavelength of λ0.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, obtaining the reference optical signal includes: receiving a first signal, the first signal being an optical signal received by the current network node from the previous network node; and filtering and extracting the reference optical signal from the first signal.

[0012] It should be understood that the wavelength calibration method of this application mainly targets the mechanism of network-wide wavelength synchronization between network nodes in one transmission direction, using the wavelength of the same reference optical signal as a reference. Therefore, the entire transmission process, from receiving a signal from the preceding network node to sending a signal to the following network node after acquiring the first target optical signal, is unidirectional. In other words, for the current network node, a pair of transceiver interfaces corresponds to one transmission direction.

[0013] It should be noted that in the embodiments of this application, "front and back" mainly refers to the direction of signal transmission, including but not limited to physical location. For example, the preceding network node of the current network node includes, but is not limited to, a position directly in front of the current node in the network system architecture. For instance, a node directly physically connected to the current network node A could be the preceding network node B, or another device C (e.g., an interface device, or a bridging device). This other device C can directly or indirectly communicate with the preceding network node B.

[0014] The first signal can be a wavelength division multiplexed signal, and this application does not specifically limit it.

[0015] In this implementation, the current network node obtains a first signal from the previous network node and filters out a reference light signal from it. A reference light signal for wavelength calibration is then generated based on this reference light. As the signal is transmitted, all network nodes perform this calibration, ultimately achieving network-wide wavelength synchronization.

[0016] It should be noted that the source of the reference optical signal in the current network node differs in different application scenarios. For the reference optical signal in a tree topology, it mainly originates from the signal transmitted from the preceding node. For example, the downlink signal transmitted from the optical line terminal (OLT) to the optical network unit (ONU) in a wavelength division multiplexing-passive optical network (WDM-PON), or the signal transmitted from the root node to the leaf nodes in a data center (DC). For the reference optical signal in a ring topology, it mainly originates from the signal of the preceding node. This application does not specifically limit this.

[0017] In conjunction with the first aspect, in some implementations of the first aspect, the form of the reference optical signal includes one of DC continuous light, low-speed intensity modulated continuous light, and low-order coherent modulated continuous light.

[0018] In this implementation, the form of the reference optical signal is more diverse, with the addition of low-speed intensity modulated continuous light and low-order coherent modulated continuous light carrying the data signal.

[0019] It should be noted that the device structure of the frequency calibration unit in this application is adapted according to the form of the reference light. For example, when the reference light signal is in the form of DC continuous light, wavelength locking technology or injection locking technology is used; when the reference light signal is in the form of low-order coherent modulated light, the laser frequency of the current network node is adjusted by extracting the phase difference, thereby realizing optical frequency calibration, such as an optical phase-locked loop scheme.

[0020] In conjunction with the first aspect, in some implementations of the first aspect, adjusting the output wavelength of the local laser according to the reference optical signal to generate a reference optical signal includes: when the reference optical signal is in the form of DC continuous light, adjusting the output wavelength of the local laser according to wavelength locking technology or injection locking technology to generate a reference optical signal.

[0021] In this implementation, for the case where the reference light is continuous DC light, wavelength locking or injection locking (IL) techniques are used to generate the reference light signal. This implementation can achieve the goal of wavelength calibration and accurately determine the reference light signal.

[0022] It should be understood that when the reference optical signal is in the form of DC continuous light, the wavelength reference is most easily extracted.

[0023] For example, the current network node uses a fiber bragg grating (FBG) that meets wavelength matching conditions to filter and extract the reference optical signal from the received signal. That is, the reference optical signal takes the reflection path, while the remaining spectrum passes through the FBG for demodulation or continued transmission. Since injection-locked technology can amplify the injected wavelength while suppressing other sidebands, it is equivalent to active, extremely narrow bandwidth filtering.

[0024] In conjunction with the first aspect, in certain implementations of the first aspect, adjusting the output wavelength of the local laser according to the reference optical signal to generate a reference optical signal includes: when the reference optical signal is in the form of low-speed intensity modulated continuous light, coupling the reference optical signal with the output optical signal of the local laser into an input coupler; inputting the coupled optical signal into a balanced detector to obtain a phase difference; and adjusting the optical frequency of the local laser according to the phase difference feedback to generate a reference optical signal.

[0025] In this implementation, for the case where the reference light is low-speed intensity modulated continuous light, a coupler and balanced probe are used to obtain the phase difference, thereby generating a reference light signal. This implementation can achieve frequency calibration with reference light modulation data. This allows some low-speed control signals to be transmitted through the reference light signal, improving resource utilization.

[0026] In conjunction with the first aspect, in certain implementations of the first aspect, adjusting the output wavelength of the local laser according to the reference optical signal to generate a reference optical signal includes: when the reference optical signal is in the form of low-order coherently modulated continuous light, inputting the reference optical signal and the output optical signal of the local laser into a 90° optical mixer to obtain the in-phase component and quadrature component of the optical signal; determining the phase difference of the optical signal according to the in-phase component and quadrature component of the optical signal; and adjusting the optical frequency of the local laser according to the phase difference of the optical signal to generate the reference optical signal.

[0027] In this implementation, for the case where the reference light is low-order coherently modulated continuous light, a 90° optical mixer is used to obtain the in-phase and quadrature components, determine the phase difference of the optical signal, and then generate the reference optical signal. This implementation modulates data with the reference light λ0, improving resource utilization. Compared with intensity modulation, it can achieve higher-rate signaling data transmission and improve the transmission quality of signaling data.

[0028] In conjunction with the first aspect, in some implementations of the first aspect, when the reference optical signal is in the form of a dual-wavelength light with wavelengths of λ0 and λ0+Δf respectively, the method further includes: adjusting the output wavelength of a first local laser according to the reference optical signal with wavelength λ0 to generate a reference optical signal with wavelength λ0; adjusting the output wavelength of a second local laser according to the reference optical signal with wavelength λ0+Δf to generate an optical signal with wavelength λ0+Δf, wherein the optical signal with wavelength λ0+Δf output by the second local laser is used to beat a portion of the optical signal of the reference light with wavelength λ0 output by the first local laser to obtain an electrical signal with frequency Δf.

[0029] In this implementation, a wavelength reference and an electrical signal frequency reference are provided simultaneously. Compared to current methods that recover the clock from data and then extract the reference, the circuit structure is simpler.

[0030] In the embodiments of this application, the beat frequency is also called photo-diode beating (PDbeating), which refers to the process where two light signals with different wavelengths enter a PD, and the PD outputs an electrical single-tone signal. The frequency of this single-tone signal is the same as the frequency difference of the light signal.

[0031] In conjunction with the first aspect, in some implementations of the first aspect, the first target optical signal is loaded with data and coupled with a reference optical signal and a second signal before being sent to the next network node. The second signal is the optical signal in the first signal that is directly transmitted to the next network node.

[0032] In this implementation, a stable frequency difference exists between the first target optical signal and the reference optical signal, thus completing the transmission of the wavelength reference. As the signal is transmitted, all network nodes will perform this calibration, ultimately achieving network-wide wavelength synchronization.

[0033] For example, the wavelength division multiplexed signal received by the current network node from its predecessor consists of three parts: a signal that needs to be resolved locally, a signal that needs to be passed through to the next network node, and a reference optical signal used as the optical frequency reference in this application. After obtaining the optical frequency reference, the current network node uses a frequency calibration device to generate the wavelength of its own transmitted data, i.e., the first target optical signal. After modulating the data with the first target signal, it is combined with the wavelength reference signal and other signals passed through to the next network node, and then sent to the next network node.

[0034] In conjunction with the first aspect, in some implementations of the first aspect, multiple target optical signals are generated based on a reference optical signal, including: generating multiple target optical signals based on a reference optical signal using optical frequency comb (OFC) technology.

[0035] In this implementation, the frequency spreading unit uses OFC technology to ensure that multiple target optical signals with relatively stable frequency differences from the reference optical signal are obtained. The frequency selection unit can determine the wavelength used for its own operation, i.e., the first target optical signal, according to the actual working needs of the current network node.

[0036] This is because each spectral line in the multiple target optical signals acquired using OFC technology has a fixed frequency difference with the reference light. Moreover, OFC technology can easily obtain a large frequency difference, thus ensuring that the system can operate over a wide wavelength range, enabling tunable frequency control for small particles and miniaturized integration.

[0037] It should be understood that OFC technology refers to a spectrum composed of a series of uniformly spaced frequency components with a coherent and stable phase relationship. OFC is widely used due to its characteristics in generating arbitrary optical waveforms, generating multi-wavelength ultrashort pulses, and dense wavelength division multiplexing.

[0038] In conjunction with the first aspect, in some implementations of the first aspect, extracting a first target optical signal from multiple target optical signals includes: extracting the first target optical signal from the optical frequency comb based on injection-locked IL technology or tunable optical filter cascaded optical amplifier technology.

[0039] In this implementation, the frequency selection unit can extract the first target optical signal suitable for its own operating wavelength through IL technology or tunable optical filter cascaded optical amplifier technology. Compared with traditional optical network systems, the wavelength selection in the network-wide wavelength calibration mechanism is more flexible and adaptable.

[0040] For example, injection-locking technology is used to extract the first target optical signal from a broadband optical frequency comb. Specifically, the broadband optical frequency comb is injected into a local laser through a circulator port, while a microprocessor (micro controller unit, MCU) tunes the local laser wavelength to the locking range. Due to the principle of injection-locking technology, the laser ultimately generates a standard first target optical signal, which is output through the circulator port. Finally, the first target optical signal is used as a carrier to modulate data. Here, the operating wavelength of each network node can be flexibly selected by adjusting the target optical signal.

[0041] For example, frequency selection can be achieved using a technique of cascading an optical filter with an optical amplifier. First, a tunable optical filter extracts the desired first target optical signal from the frequency comb. Then, an optical amplifier increases the power, and finally, the signal enters the optical modulator. Based on this first target optical signal, a data signal can be loaded, improving the quality of signal transmission.

[0042] Secondly, a wavelength calibration apparatus is provided, comprising: a processing unit for acquiring a reference optical signal; a frequency calibration unit for adjusting the output wavelength of a local laser according to the reference optical signal to generate a reference optical signal, wherein the reference optical signal has the same wavelength as the reference optical signal; a frequency spreading unit for generating multiple target optical signals based on the reference optical signal, wherein each target optical signal has a different wavelength and the frequency difference between each target optical signal and the reference optical signal is different and fixed; and a frequency selection unit for extracting a first target optical signal from the multiple target optical signals for data transmission.

[0043] According to the scheme provided in this application, a reference light is acquired, and a reference light is generated based on the reference light. Then, a first target optical signal with a stable frequency difference from the reference light is generated for loading data during its own operation. This method is applicable to all network nodes in the system. By using a unified wavelength reference for wavelength calibration, it can ensure that the optical network nodes have stable frequency errors. This reduces the guard bandgap when the network adopts a flexible grid deployment, improves the network spectrum utilization efficiency, and thus ensures the signal transmission quality.

[0044] The technical solution presented in this application is applied to flexible optical networks, such as multi-level ring network structures. After wavelength calibration across the entire network, the spectral spacing of laser wavelengths between network nodes is stable, thus avoiding spectral aliasing caused by random laser frequency differences. Therefore, guard band spacing between spectra can be eliminated, improving spectral utilization. Compared to traditional optical networks, all-optical networks offer greater flexibility, transparency, compatibility, and scalability. Furthermore, while ensuring wavelength synchronization, signal add / drop and sub-band optical switching at each network node can be flexibly implemented.

[0045] It should be noted that the reference optical signal and the standard optical signal have the same wavelength. Due to signal distortion or path loss differences, in order to ensure the current network node... X Mid-wavelength calibration and signal transmission quality require adjusting the wavelength of the local laser based on the reference light to obtain a reference light with high signal quality, so as to realize the subsequent wavelength calibration mechanism.

[0046] For example, the reference optical signal may refer to a continuous DC optical signal with a wavelength of λ0.

[0047] In conjunction with the second aspect, in some implementations of the second aspect, the device further includes: a transceiver unit for receiving a first signal, the first signal being an optical signal received by the current network node from the previous network node; and a processing unit for filtering and extracting a reference optical signal from the first signal.

[0048] It should be understood that the wavelength calibration method of this application mainly targets the mechanism of network-wide wavelength synchronization between network nodes in one transmission direction, using the wavelength of the same reference optical signal as a reference. Therefore, the entire transmission process, from receiving a signal from the preceding network node to sending a signal to the following network node after acquiring the first target optical signal, is unidirectional. In other words, for the current network node, a pair of transceiver interfaces corresponds to one transmission direction.

[0049] It should be noted that in the embodiments of this application, "front and back" mainly refers to the direction of signal transmission, including but not limited to physical location. For example, the preceding network node of the current network node includes, but is not limited to, a position directly in front of the current node in the network system architecture. For instance, a node directly physically connected to the current network node A could be the preceding network node B, or another device C (e.g., an interface device, or a bridging device). This other device C can directly or indirectly communicate with the preceding network node B.

[0050] The first signal can be a wavelength division multiplexed signal, and this application does not specifically limit it.

[0051] In this implementation, the current network node obtains a first signal from the previous network node and filters out a reference optical signal from it. A reference optical signal for wavelength calibration is then generated based on this reference light. As the signal is transmitted, all network nodes perform this calibration, ultimately achieving network-wide wavelength synchronization.

[0052] It should be noted that the source of the reference optical signal in the current network node differs in different application scenarios. For the reference optical signal in a tree topology, it mainly originates from the signal transmitted from the preceding node. For example, the downlink signal sent from the optical line terminal (OLT) to the optical network unit (ONU) in a wavelength division multiplexing passive fiber optic network (WDM-PON), and the signal sent from the root node to the leaf nodes in a data center (DC). For the reference optical signal in a ring topology, it mainly originates from the signal of the preceding node. This application does not specifically limit this.

[0053] In conjunction with the second aspect, in some implementations of the second aspect, the form of the reference optical signal includes one of DC continuous light, low-speed intensity modulated continuous light, and low-order coherent modulated continuous light.

[0054] In this implementation, the form of the reference optical signal is more diverse, with the addition of low-speed intensity modulated continuous light and low-order coherent modulated continuous light carrying the data signal.

[0055] It should be noted that the device structure of the frequency calibration unit in this application is adapted according to the form of the reference light. For example, when the reference light signal is in the form of DC continuous light, wavelength locking technology or injection locking technology is used; when the reference light signal is in the form of low-order coherent modulated light, the laser frequency of the current network node is adjusted by extracting the phase difference, thereby realizing optical frequency calibration, such as an optical phase-locked loop scheme.

[0056] In conjunction with the second aspect, in some implementations of the second aspect, when the reference optical signal is in the form of DC continuous light, the frequency calibration unit is also used to adjust the output wavelength of the local laser according to wavelength locking technology or injection locking technology to generate a reference optical signal.

[0057] In this implementation, for the case where the reference light is continuous DC light, a wavelength-locked or injection-locked (IL) technique is used to generate a reference optical signal. This implementation can achieve the goal of wavelength calibration and accurately determine the reference optical signal.

[0058] It should be understood that when the reference optical signal is in the form of DC continuous light, the wavelength reference is most easily extracted.

[0059] For example, the current network node uses a fiber bragg grating (FBG) that meets wavelength matching conditions to filter and extract the reference optical signal from the received signal. That is, the reference optical signal takes the reflection path, while the remaining spectrum passes through the FBG for demodulation or continued transmission. Since injection-locked technology can amplify the injected wavelength while suppressing other sidebands, it is equivalent to active, extremely narrow bandwidth filtering.

[0060] In conjunction with the second aspect, in some implementations of the second aspect, when the reference optical signal is in the form of low-speed intensity modulated continuous light, the frequency calibration unit is also used to couple the reference optical signal with the output optical signal of the local laser to the input coupler; input the coupled optical signal to the balanced detector to obtain the phase difference; and adjust the optical frequency of the local laser according to the phase difference feedback to generate the reference optical signal.

[0061] In this implementation, for the case where the reference light is low-speed intensity modulated continuous light, a coupler and balanced probe are used to obtain the phase difference, thereby generating a reference light signal. This implementation can achieve frequency calibration with reference light modulation data. This allows some low-speed control signals to be transmitted through the reference light signal, improving resource utilization.

[0062] In conjunction with the second aspect, in some implementations of the second aspect, when the reference optical signal is in the form of low-order coherently modulated continuous light, the frequency calibration unit is also used to input the reference optical signal and the output optical signal of the local laser into a 90° optical mixer to obtain the in-phase component and quadrature component of the optical signal; determine the phase difference of the optical signal based on the in-phase component and quadrature component of the optical signal; and adjust the optical frequency of the local laser based on the phase difference of the optical signal to generate a reference optical signal.

[0063] In this implementation, for the case where the reference light is low-order coherently modulated continuous light, a 90° optical mixer is used to obtain the in-phase and quadrature components, determine the phase difference of the optical signal, and then generate the reference optical signal. This implementation modulates data with the reference light λ0, improving resource utilization. Compared with intensity modulation, it can achieve higher-rate signaling data transmission and improve the transmission quality of signaling data.

[0064] In conjunction with the second aspect, in some implementations of the second aspect, when the reference optical signal is in the form of a dual-wavelength light with wavelengths of λ0 and λ0+Δf respectively, the frequency calibration unit is further configured to adjust the output wavelength of the first local laser according to the reference optical signal with wavelength λ0 to generate a reference optical signal with wavelength λ0; the frequency calibration unit is further configured to adjust the output wavelength of the second local laser according to the reference optical signal with wavelength λ0+Δf to generate an optical signal with wavelength λ0+Δf, wherein the optical signal with wavelength λ0+Δf output by the second local laser is used to beat with a portion of the optical signal of the reference light with wavelength λ0 output by the first local laser to obtain an electrical signal with frequency Δf.

[0065] In this implementation, a wavelength reference and an electrical signal frequency reference are provided simultaneously. Compared to current methods that recover the clock from data and then extract the reference, the circuit structure is simpler.

[0066] In the embodiments of this application, the beat frequency is also called photo-diode beating (PDbeating), which refers to the process where two light signals with different wavelengths enter a PD, and the PD outputs an electrical single-tone signal. The frequency of this single-tone signal is the same as the frequency difference of the light signal.

[0067] In conjunction with the second aspect, in some implementations of the second aspect, the transceiver unit is also used to load data onto the first target optical signal through the processing unit, and then couple it with the reference optical signal and the second signal before sending it to the next network node, wherein the second signal is the optical signal that is directly transmitted to the next network node from the first signal.

[0068] In this implementation, a stable frequency difference exists between the first target optical signal and the reference optical signal, thus completing the transmission of the wavelength reference. As the signal is transmitted, all network nodes will perform this calibration, ultimately achieving network-wide wavelength synchronization.

[0069] For example, the wavelength division multiplexed signal received by the current network node from the previous node includes three parts: a signal that needs to be resolved locally, a signal that needs to be passed through to the next network node, and a reference optical signal used as the optical frequency reference in this application. After obtaining the optical frequency reference, the current network node uses a frequency calibration device to generate the wavelength of its own transmitted data, i.e., the first target optical signal. After modulating the data with the first target signal, it is combined with the wavelength reference signal and other signals passed through to the next network node, and then sent to the next network node.

[0070] In conjunction with the second aspect, in some implementations of the second aspect, multiple target optical signals are generated based on a reference optical signal, including: generating multiple target optical signals based on a reference optical signal using optical frequency comb (OFC) technology.

[0071] In this implementation, the frequency spreading unit uses OFC technology to ensure that multiple target optical signals with relatively stable frequency differences from the reference optical signal are obtained. The frequency selection unit can determine the wavelength used for its own operation, i.e., the first target optical signal, according to the actual working needs of the current network node.

[0072] This is because each spectral line in the multiple target optical signals acquired using OFC technology has a fixed frequency difference with the reference light. Moreover, OFC technology can easily obtain a large frequency difference, thus ensuring that the system can operate over a wide wavelength range, enabling tunable frequency control for small particles and miniaturized integration.

[0073] It should be understood that OFC technology refers to a spectrum composed of a series of uniformly spaced frequency components with a coherent and stable phase relationship. OFC is widely used due to its characteristics in generating arbitrary optical waveforms, generating multi-wavelength ultrashort pulses, and dense wavelength division multiplexing.

[0074] In conjunction with the second aspect, in some implementations of the second aspect, extracting a first target optical signal from multiple target optical signals includes: extracting the first target optical signal from the optical frequency comb based on injection-locked IL technology or tunable optical filter cascaded optical amplifier technology.

[0075] In this implementation, the frequency selection unit can extract the first target optical signal suitable for its own operating wavelength through IL technology or tunable optical filter cascaded optical amplifier technology. Compared with traditional optical network systems, the wavelength selection in the network-wide wavelength calibration mechanism is more flexible and adaptable.

[0076] For example, injection-locking technology is used to extract the first target optical signal from a broadband optical frequency comb. Specifically, the broadband optical frequency comb is injected into a local laser through a circulator port, while a microprocessor (MCU) tunes the local laser wavelength to the locking range. Due to the principle of injection-locking technology, the laser ultimately generates a standard first target optical signal, which is output through the circulator port. Finally, the first target optical signal is used as a carrier to modulate data. Here, the operating wavelength of each network node can be flexibly selected by adjusting the target optical signal.

[0077] For example, frequency selection can be achieved using a technique of cascading an optical filter with an optical amplifier. First, a tunable optical filter extracts the desired first target optical signal from the frequency comb. Then, an optical amplifier increases the power, and finally, the signal enters the optical modulator. Based on this first target optical signal, a data signal can be loaded, improving the quality of signal transmission.

[0078] Thirdly, a full-network wavelength calibration device is provided, including a processor, and optionally, a memory, the processor for controlling a transceiver to transmit and receive signals, the memory for storing a computer program, and the processor for calling and running the computer program from the memory, causing the device to perform the methods in the first aspect or any possible implementation of the first aspect.

[0079] Optionally, the processor may be one or more, and the memory may be one or more.

[0080] Alternatively, the memory can be integrated with the processor, or the memory can be set separately from the processor.

[0081] Optionally, the device may also include a transceiver, which may specifically be a transmitter and a receiver.

[0082] Fourthly, an optical communication device is provided, comprising: various modules or units for implementing the method of the first aspect or any possible implementation of the first aspect.

[0083] Fifthly, an optical communication system is provided, comprising: an optical network node for performing the method described in the first aspect or any possible implementation thereof.

[0084] In a sixth aspect, a computer-readable storage medium is provided that stores a computer program or code, which, when executed on a computer, causes the computer to perform the methods described in the first aspect or any possible implementation thereof.

[0085] In a seventh aspect, a chip is provided, including at least one processor coupled to a memory for storing a computer program, the processor for calling and running the computer program from the memory, such that an optical network node equipped with the chip system performs the methods of the first aspect or any possible implementation thereof.

[0086] The chip may include an input circuit or interface for transmitting information or data, and an output circuit or interface for receiving information or data.

[0087] Eighthly, a computer program product is provided, comprising: computer program code, which, when executed by an optical network node, causes the optical network node to perform the method described in the first aspect or any possible implementation thereof.

[0088] According to the embodiments of this application, a method and apparatus for full-network wavelength calibration are provided. This involves acquiring reference light, generating a reference light based on the reference light, and then generating a first target optical signal with a stable frequency difference from the reference light for loading data during operation. This method is applicable to all network nodes in the system. By using a unified wavelength reference for wavelength calibration, it ensures stable frequency errors in optical network nodes, reducing guard bandgap and improving network spectrum utilization efficiency when the network is deployed with a flexible grid, thereby guaranteeing signal transmission quality. Attached Figure Description

[0089] Figure 1 This is a schematic diagram of a multi-level ring network architecture applicable to this application.

[0090] Figure 2 This is a schematic diagram of a current wavelength calibration method.

[0091] Figure 3 This is a schematic diagram of an example of the process of generating a co-frequency optical carrier from a wavelength reference at a node.

[0092] Figure 4 This is a schematic diagram of an example of the wavelength calibration method applicable to this application.

[0093] Figure 5 This is a schematic diagram illustrating an example of the working principle of wavelength calibration within a network node applicable to this application.

[0094] Figure 6 This is a schematic diagram illustrating the working principle of the wavelength calibration device applicable to this application.

[0095] Figure 7 This is a schematic diagram of an optical frequency calibration device applicable to this application.

[0096] Figure 8 This is another schematic diagram of an optical frequency calibration device applicable to this application.

[0097] Figure 9 This is another schematic diagram of an optical frequency calibration device applicable to this application.

[0098] Figure 10 This is a schematic diagram of an optical frequency selection device applicable to this application.

[0099] Figure 11 This is another schematic diagram of an optical frequency calibration device applicable to this application.

[0100] Figure 12 This is another schematic diagram of an optical frequency calibration device applicable to this application.

[0101] Figure 13 This is another schematic diagram of an optical frequency calibration device applicable to this application. Detailed Implementation

[0102] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0103] This application is mainly used in elastic optical networks (EON). Figure 1 This is a schematic diagram of a multi-level ring network architecture applicable to this application. For example... Figure 1 As shown, after wavelength calibration across the entire network, the spectral spacing of laser wavelengths between network nodes is stable. This avoids spectral aliasing caused by random frequency differences in lasers, thus eliminating the need for guard intervals between spectra. For example, when data from network nodes A and B needs to be converged to network node C, two adjacent spectrum segments from nodes A and B can be allocated and converged directly at node C using a multiplexing method. This creates a super channel at node C, where the various optical signals carrying information can be seamlessly spliced ​​across the spectrum.

[0104] Similarly, when data from network nodes C and D needs to converge to network node E, two adjacent spectrum segments from nodes C and D can be allocated, and these two spectrum segments can be directly converged at node E using a multiplexing method. That is, this method can be used when data from each level of nodes converges upwards.

[0105] This implementation method ensures end-to-end all-optical information transmission, replacing the traditional back-to-back optical terminal equipment setup, saving expensive electrical repeater costs, and avoiding latency caused by multi-level data processing. Furthermore, compared to traditional optical networks, all-optical networks offer greater flexibility, transparency, compatibility, and scalability. In addition, while ensuring wavelength synchronization, signal add / drop and sub-wavelength band switching can be flexibly implemented at each node.

[0106] To facilitate understanding of the embodiments of this application, a brief explanation of several terms involved in this application will be given first.

[0107] 1. Optical Phase-Locked Loop (OPLL): An OPLL is a system that controls the frequency of a laser's output signal through signal phase feedback. This allows the slave laser to track the frequency of the master laser and maintain consistency with the master laser's frequency changes, thus achieving a constant output signal frequency difference. Similar to electrical phase-locked loops, optical phase-locked loops consist of three parts: phase difference extraction, loop filtering, and a voltage-controlled oscillator (VCO). The VCO uses the output signal of the loop filter to control the laser's frequency and phase.

[0108] 2. Injection Locking (IL): IL refers to inputting external light into a semiconductor light source through a circulator, tuning the wavelength of the injected light source to near a wavelength component of the external input light (i.e., the target wavelength component), so that the wavelength of the injected light source is within the lockable region of the target wavelength component. This implementation ensures that the frequency of the final output light is equal to that of the injected light because the laser light source internally functions like a frequency-selective filter element, where only the locked frequency component can oscillate.

[0109] 3. Elastic Optical Network (EON): Traditional optical transport networks are based on WDM technology and have a fixed spectrum grid. Each spectrum grid corresponds to one optical channel with a fixed center frequency and spectral width. However, the WDM architecture suffers from low spectral utilization, inability to dynamically adjust optical channels, and inflexibility. Therefore, EON proposes to break away from the limitations of the fixed spectrum grid in traditional optical networks. Through software control, the carrier center frequency can be located at any position on the spectrum, with distance-adaptive modulation formats and spectral widths, thereby increasing spectral utilization efficiency and flexibility.

[0110] 4. Optical Frequency Comb (OFC): OFC refers to a spectrum consisting of a series of uniformly spaced frequency components with a coherent and stable phase relationship. OFC is usually generated by a mode-locked laser, and the frequency components can be spread through a highly efficient nonlinear medium.

[0111] 5. Metropolitan Area Network (MAN): The deployment of communication networks generally includes a three-tier architecture of backbone network-MAN-access network, as well as a two-tier architecture of national backbone network-MAN that has gradually emerged in recent years. The backbone network primarily focuses on transmission capacity, while the MAN's role is to achieve effective access, routing, and aggregation of various services. Furthermore, the MAN must not only be compatible with various uplink and downlink signals but also possess the bandwidth required for the corresponding services; the key cost lies at the nodes.

[0112] The development requirements for metropolitan area networks include: scalability (i.e., flexibility, high efficiency, and strong scalability), sub-rate configuration (i.e., high bandwidth efficiency, able to meet the needs of more users), fast and intelligent configuration (i.e., fast connection establishment), and node transparency (i.e., support for multiple signal formats, reducing conversion costs).

[0113] 6. Ring Network: Also known as a ring-shaped network. In metropolitan area network wavelength division multiplexing (WDM) systems, ring networks are most commonly used and have self-healing protection capabilities. Optical add-drop module (OADM) technology is used at the nodes to enable flexible add-drop scheduling.

[0114] 7. Super channel: A super channel has multiple optical wavelength signals that are densely arranged in the spectrum and are usually transmitted and exchanged as a whole.

[0115] To facilitate understanding of the embodiments of this application, the following points are made:

[0116] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions of different embodiments are consistent and can be referenced by each other. The technical features of different embodiments can be combined to form new embodiments according to their inherent logical relationship.

[0117] In this application, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0118] In the embodiments of this application, the terms "first," "second," and various numerical designations are used for ease of description and are not intended to limit the scope of the embodiments of this application. For example, they can be used to distinguish different indication information.

[0119] In the embodiments of this application, descriptions such as "when," "under the circumstances," "if," and "if" all refer to the device making corresponding processing under certain objective circumstances, and are not limited to a specific time. They do not require the device to make a judgment action during implementation, nor do they imply any other limitations.

[0120] Currently, with the development of technology, data traffic generated by services such as cloud computing, artificial intelligence, live streaming, and short videos exhibits characteristics such as high peak rates and rapid dynamic changes. As the cornerstone of the entire communication system, fiber optic networks therefore face the dual requirements of high bandwidth and flexible intelligence. Besides traditional backbone networks, metropolitan area networks, and access networks, more and more data networks in various scenarios are choosing fiber optic transmission systems as the next-generation technology option. Examples include the Industrial Internet and the Internet of Vehicles. These optical networks contain multiple network nodes and have the need for multi-point to multi-point collaborative communication. Therefore, improving network flexibility is a crucial issue that fiber optic communication networks must address. This includes flexible allocation of wavelengths and bandwidth, effective service access at nodes, and routing and aggregation. Generally, optical networks use wavelength division multiplexing (WDM) with a fixed grid, where multiple multiplexed wavelengths can only be transmitted using the same single rate—a "rigid pipe" allocation. With the rise of services with diversified bandwidth demands and the development of optical network technology, next-generation optical networks will evolve towards flexible optical networks with mixed rates and flexible grids. In an ideal flexible grid elastic optical network, signals from each network node should be closely aligned in the spectrum to maximize spectral utilization efficiency, reduce limiting factors when allocating spectrum, and improve network flexibility.

[0121] However, physical layer signal impairments such as crosstalk limit the minimum guard bandgap setting between spectra. Crosstalk sources include adjacent-channel crosstalk caused by factors such as device imperfections, as well as fiber nonlinear effects such as cross-phase modulation and four-wave mixing. For short-distance transmission scenarios such as metropolitan area networks, access networks, and industrial networks, fiber nonlinear effects are not severe due to the short transmission distance. Therefore, adjacent-channel crosstalk caused by device imperfections becomes the dominant factor affecting the minimum guard bandgap setting. Among these, the impact of random frequency differences between lasers at different network nodes is most prominent, with the laser frequency difference range specified in the 400G ZR standard reaching ±1.8GHz. Taking the multi-point-to-point transmission architecture proposed by Infinera (e.g., XR optics) as an example, data from multiple edge nodes are loaded onto Nyquist-shaped signals with non-overlapping optical frequencies. At the hub node, spectrum aggregation is performed directly in the optical domain, and the signal is then transmitted to the root node for detection and processing by an optical receiver. However, due to the random frequency differences of the lasers at each edge, optical aggregation at the hub node leads to spectral aliasing, causing a degraded signal quality. Therefore, this problem can be avoided by using a guard band approach. However, the spectral efficiency will also decrease, especially when there are many edge nodes. Therefore, if the optical frequencies of all network nodes have a unified reference, the limitations on network flexibility and spectral efficiency caused by random frequency differences in lasers can be avoided.

[0122] Figure 2 This is a schematic diagram of a current wavelength calibration method. For example... Figure 2 As shown, firstly, a network node is selected as the master node, and a set of wavelength-stable spectra is generated at the master node as a wavelength reference (i.e., a frequency reference). Then, the wavelength reference is sent to the slave nodes. In each slave node, a continuous optical signal of the same frequency is generated based on the reference light, serving as the carrier for the data stream.

[0123] Specifically, an optical frequency comb signal is generated at the master node. Different spectral lines serve as wavelength references for different slave nodes, with stable frequency intervals between them. The optical frequency comb signal is then transmitted through optical fiber and distributed to the slave nodes.

[0124] It should be noted that the distribution process of the optical frequency comb signal involves a two-stage filtering process. The first stage is... Figure 2 The passive filter shown transmits multiple spectral lines through a passband of the wavelength divider, and then distributes them to the slave nodes by the optical power divider.

[0125] Figure 3 This is a schematic diagram illustrating an example of the process of generating a co-frequency optical carrier from a wavelength reference at a node; the second stage is... Figure 3 The active filtering shown refers to the process where each slave node actually receives multiple wavelength references and uses active filtering technology to obtain an adaptive wavelength reference. In this implementation, the local laser can be tuned to near the reference wavelength using injection locking (IL) technology. Due to the frequency pulling effect, the local laser excites an optical signal that is in phase and frequency with the wavelength reference, which serves as the final carrier-loaded data.

[0126] For example, in the automatic wavelength tracking and locking module of the slave node, external light (filtered) is injected into a distributed feedback laser (DFB) through ports 1 and 2 of the circulator. The DFB determines the wavelength corresponding to the input spectral line and sends it to port 2. Then, port 2 inputs the optical signal of this wavelength into port 3. The output optical signal is transmitted and processed by a photodiode (PD), detector, microprocessor, and driver before being fed back to the DFB, thereby completing the generation of the same-frequency optical carrier.

[0127] In this implementation, each slave node maintains a stable frequency difference with the master node, enabling full network wavelength synchronization. Furthermore, each slave node employs automatic wavelength reference locking and tracking technology, giving the optical network system adaptability. This means that minor adjustments to the wavelength of the injected light source will not affect the synchronous operation between the two light sources, thus avoiding performance degradation caused by uncertain wavelength drift due to environmental changes.

[0128] However, since the operating wavelength references of different network slave nodes are fixed, a wide range of tunable operating wavelengths cannot be achieved. Furthermore, in this implementation, the operating bandwidth of each network node must be less than the spectral line spacing of the optical frequency comb (OFC), preventing the allocation of large operating bandwidths to any network node and thus limiting the flexibility of spectrum allocation in flexible optical networks. Moreover, in the current scheme, the operating wavelength of each network node is uniformly generated at the master node and then distributed to each branch node, which cannot achieve flexible tuning or flexible spectrum allocation. Finally, this technology is only suitable for tree-structured networks and not for other network topologies, thus having certain limitations.

[0129] In summary, considering that future networks need to develop towards flexible optical networks and flexible spectrum allocation, and that the lasers of each network node are independent of each other, which can easily generate random frequency differences at the gigahertz (GHz) level, this limits the development of network flexibility and spectrum utilization efficiency.

[0130] In view of this, this application provides a method for full-network wavelength calibration, employing a working mechanism where all nodes in the network perform optical frequency calibration based on a unified wavelength reference. Even if the laser wavelength experiences jitter and drift, each network node can lock onto and track the network wavelength reference, thus ensuring that the wavelengths of each network node always have stable frequency and phase differences. A reference light is acquired, and a reference light is generated based on the reference light. Then, a first target optical signal with a stable frequency difference from the reference light is generated for its own operational data loading. This method is applicable to all network nodes in the system. By using a unified wavelength reference for wavelength calibration, it ensures that the optical network nodes have stable frequency errors, reducing the guard bandgap and improving network spectrum utilization efficiency when the network is deployed in a flexible grid, thereby guaranteeing signal transmission quality. Simultaneously, a device design for implementing optical frequency calibration in each network node is provided, including the design of a frequency calibration unit, a frequency expansion unit, and a frequency selection unit, achieving the goal of full-network optical wavelength synchronization and ensuring that each node can flexibly generate its own operating wavelength.

[0131] The wavelength calibration method provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0132] Figure 4 This is a schematic diagram illustrating an example of the network-wide wavelength calibration method applicable to this application. Specific implementation steps 400 include:

[0133] S410, acquire the reference optical signal.

[0134] The reference optical signal can take one of the following forms: DC continuous light, low-speed intensity modulated continuous light, or low-order coherent modulated continuous light.

[0135] It should be understood that the form of the reference optical signal is more diverse, with the addition of low-speed intensity modulated continuous light and low-order coherent modulated continuous light carrying data signals.

[0136] It should be noted that the device structure of the frequency calibration unit in this application is adapted according to the form of the reference light. For example, when the reference light signal is in the form of DC continuous light, wavelength locking technology or injection locking technology is used; when the reference light signal is in the form of low-order coherent modulated light, the laser frequency of the current network node is adjusted by extracting the phase difference, thereby realizing optical frequency calibration, such as an optical phase-locked loop scheme.

[0137] For example, acquiring a reference optical signal includes: receiving a first signal, the first signal being an optical signal received by the current network node from the previous network node; and filtering and extracting a reference optical signal from the first signal.

[0138] It should be understood that the wavelength calibration method of this application mainly targets the mechanism of network-wide wavelength synchronization between network nodes in one transmission direction, using the wavelength of the same reference optical signal as a reference. Therefore, the entire transmission process, from receiving a signal from the preceding network node to sending a signal to the following network node after acquiring the first target optical signal, is unidirectional. In other words, for the current network node, a pair of transceiver interfaces corresponds to one transmission direction.

[0139] It should be noted that in the embodiments of this application, "front and back" mainly refers to the direction of signal transmission, including but not limited to physical location. For example, the preceding network node of the current network node includes, but is not limited to, a position directly in front of the current node in the network system architecture. For instance, a node directly physically connected to the current network node A could be the preceding network node B, or another device C (e.g., an interface device, or a bridging device). This other device C can directly or indirectly communicate with the preceding network node B.

[0140] The first signal can be a wavelength division multiplexed signal, and this application does not specifically limit it.

[0141] In this implementation, the current network node obtains a first signal from the previous network node and filters out a reference optical signal from it. A reference optical signal for wavelength calibration is then generated based on this reference light. As the signal is transmitted, all network nodes perform this calibration, ultimately achieving network-wide wavelength synchronization.

[0142] It should be noted that the source of the reference optical signal in the current network node differs in different application scenarios. For the reference optical signal in a tree topology, it mainly originates from the signal transmitted from the preceding node. For example, the downlink signal transmitted from the Optical Line Terminal (OLT) to the Optical Network Unit (ONU) in a WDM-PON network, or the signal transmitted from the root node to the leaf nodes in a data center (DC). For the reference optical signal in a ring topology, it mainly originates from the signal of the preceding node. This application does not specifically limit this.

[0143] The S420 adjusts the output wavelength of the local laser according to the reference optical signal to generate a reference optical signal.

[0144] The reference optical signal has the same wavelength as the standard optical signal, and the reference optical signal can be a continuous optical signal with a wavelength of λ0.

[0145] It should be noted that the reference optical signal and the base optical signal have the same wavelength. Due to signal distortion or path loss differences, in order to ensure the current network node... X Mid-wavelength calibration and signal transmission quality require adjusting the wavelength of the local laser based on a reference light to obtain a reference light with high signal quality, thus enabling subsequent wavelength calibration mechanisms. One possible implementation is to adjust the output wavelength of the local laser using wavelength-locked or injection-locked techniques when the reference light signal is in the form of DC continuous light, thereby generating a reference light signal.

[0146] In this implementation, for the case where the reference light is continuous DC light, a wavelength-locked or injection-locked (IL) technique is used to generate a reference optical signal. This implementation can achieve the goal of wavelength calibration and accurately determine the reference optical signal.

[0147] It should be understood that when the reference optical signal is in the form of DC continuous light, the wavelength reference is most easily extracted.

[0148] For example, the current network node uses a fiber bragg grating (FBG) that meets wavelength matching conditions to filter and extract the reference optical signal from the received signal. That is, the reference optical signal travels along the reflection path, while the remaining spectrum passes through the FBG for demodulation or continued transmission. Since injection-locked technology can amplify the injected wavelength while suppressing other sidebands, it is equivalent to active, extremely narrow bandwidth filtering. Another possible implementation, when the reference optical signal is in the form of low-speed intensity modulated continuous light, couples the reference optical signal with the output optical signal of the local laser to an input coupler; the coupled optical signal is then input to a balanced detector to obtain the phase difference; the optical frequency of the local laser is adjusted based on the phase difference feedback to generate a reference optical signal.

[0149] In this implementation, for the case where the reference light is low-speed intensity modulated continuous light, a coupler and balanced probe are used to obtain the phase difference, thereby generating a reference optical signal. This implementation can achieve frequency calibration with reference light modulation data. This allows some low-speed control signals to be transmitted through the reference optical signal, improving resource utilization. Another possible implementation, when the reference optical signal is low-order coherent modulated continuous light, involves inputting the reference optical signal and the output optical signal of the local laser into a 90° optical mixer to obtain the in-phase and quadrature components of the optical signal; determining the phase difference of the optical signal based on the in-phase and quadrature components; and adjusting the optical frequency of the local laser based on the phase difference to generate the reference optical signal.

[0150] In this implementation, for the case where the reference light is low-order coherently modulated continuous light, a 90° optical mixer is used to obtain in-phase and quadrature components, and the phase difference of the optical signal is determined to generate a reference optical signal. This implementation modulates data with the reference light λ0, improving resource utilization. Compared with intensity modulation, it can achieve higher-speed signaling data transmission and improve the transmission quality of signaling data. Another possible implementation, when the reference optical signal is a dual-wavelength light with wavelengths λ0 and λ0+Δf, further includes: adjusting the output wavelength of a first local laser based on the reference optical signal with wavelength λ0 to generate a reference optical signal with wavelength λ0; adjusting the output wavelength of a second local laser based on the reference optical signal with wavelength λ0+Δf to generate an optical signal with wavelength λ0+Δf; the optical signal with wavelength λ0+Δf output from the second local laser is used to beat with a portion of the reference optical signal with wavelength λ0 output from the first local laser to obtain an electrical signal with frequency Δf.

[0151] In this implementation, a wavelength reference and an electrical signal frequency reference are provided simultaneously. Compared to current methods that recover the clock from data and then extract the reference, the circuit structure is simpler.

[0152] In the embodiments of this application, the beat frequency is also called photo-diode beating (PDbeating), which refers to the process where two light signals with different wavelengths enter a PD, and the PD outputs an electrical single-tone signal. The frequency of this single-tone signal is the same as the frequency difference of the light signal.

[0153] S430 generates multiple target optical signals based on a reference optical signal.

[0154] Each of the multiple target optical signals has a different wavelength, and the frequency difference between each target optical signal and the reference optical signal is different and fixed.

[0155] One possible implementation is to generate multiple target optical signals based on a reference optical signal using optical frequency comb (OFC) technology.

[0156] In this implementation, the frequency spreading unit uses OFC technology to ensure that multiple target optical signals with relatively stable frequency differences from the reference optical signal are obtained. The frequency selection unit can determine the wavelength used for its own operation, i.e., the first target optical signal, according to the actual working needs of the current network node.

[0157] This is because each spectral line in the multiple target optical signals acquired using OFC technology has a fixed frequency difference with the reference light. Moreover, OFC technology can easily obtain a large frequency difference, thus ensuring that the system can operate over a wide wavelength range, enabling tunable frequency control for small particles and miniaturized integration.

[0158] It should be understood that OFC technology refers to a spectrum composed of a series of uniformly spaced frequency components with a coherent and stable phase relationship. OFC is widely used due to its characteristics in generating arbitrary optical waveforms, generating multi-wavelength ultrashort pulses, and dense wavelength division multiplexing.

[0159] S440 extracts the first target optical signal from multiple target optical signals for data transmission.

[0160] The first target optical signal has a wavelength of λ. x DC continuous optical signal.

[0161] One possible implementation method for extracting a first target optical signal from multiple target optical signals includes: extracting the first target optical signal from the optical frequency comb using injection-locked IL technology or tunable optical filter cascaded optical amplifier technology.

[0162] In this implementation, the frequency selection unit can extract the first target optical signal suitable for its own operating wavelength through IL technology or tunable optical filter cascaded optical amplifier technology. Compared with traditional optical network systems, the wavelength selection in the network-wide wavelength calibration mechanism is more flexible and adaptable.

[0163] For example, injection-locking technology is used to extract the first target optical signal from a broadband optical frequency comb. Specifically, the broadband optical frequency comb is injected into a local laser through a circulator port, while a microprocessor (MCU) tunes the local laser wavelength to the locking range. Due to the principle of injection-locking technology, the laser ultimately generates a standard first target optical signal, which is output through the circulator port. Finally, the first target optical signal is used as a carrier to modulate data. Here, the operating wavelength of each network node can be flexibly selected by adjusting the target optical signal.

[0164] For example, frequency selection can be achieved using a technique of cascading an optical filter with an optical amplifier. First, a tunable optical filter extracts the desired first target optical signal from the frequency comb. Then, an optical amplifier increases the power, and finally, the signal enters the optical modulator. Based on this first target optical signal, a data signal can be loaded, improving the quality of signal transmission.

[0165] As an example and not a limitation, based on the above implementation, the current network node loads data onto the first target optical signal, couples it with the reference optical signal and the second signal, and sends it to the next network node. The second signal is the optical signal that is directly transmitted to the next network node from the first signal.

[0166] In this implementation, a stable frequency difference exists between the first target optical signal and the reference optical signal, thus completing the transmission of the wavelength reference. As the signal is transmitted, all network nodes will perform this calibration, ultimately achieving network-wide wavelength synchronization.

[0167] For example, the wavelength division multiplexed signal received by the current network node from the previous node includes three parts: a signal that needs to be resolved locally, a signal that needs to be passed through to the next network node, and a reference optical signal used as the optical frequency reference in this application. After obtaining the optical frequency reference, the current network node uses a frequency calibration device to generate the wavelength of its own transmitted data, i.e., the first target optical signal. After modulating the data with the first target signal, it is combined with the wavelength reference signal and other signals passed through to the next network node, and then sent to the next network node.

[0168] The technical solution presented in this application is applied to flexible optical networks, such as multi-level ring network structures. After wavelength calibration across the entire network, the spectral spacing of laser wavelengths between network nodes is stable, thus avoiding spectral aliasing caused by random laser frequency differences. Therefore, guard band spacing between spectra can be eliminated, improving spectral utilization. Compared to traditional optical networks, all-optical networks offer greater flexibility, transparency, compatibility, and scalability. Furthermore, while ensuring wavelength synchronization, signal add / drop and sub-band optical switching at each network node can be flexibly implemented.

[0169] According to the scheme provided in this application, a reference light is acquired, and a reference light is generated based on the reference light. Then, a first target optical signal with a stable frequency difference from the reference light is generated for loading data during its own operation. This method is applicable to all network nodes in the system. By using a unified wavelength reference for wavelength calibration, it can ensure that the optical network nodes have stable frequency errors. This reduces the guard bandgap when the network adopts a flexible grid deployment, improves the network spectrum utilization efficiency, and thus ensures the signal transmission quality.

[0170] Figure 5This is a schematic diagram illustrating the working principle of wavelength calibration within a network node applicable to this application. Assuming the entire network uniformly uses λ0 as the wavelength reference, each network node obtains a low-quality optical signal λ0 from the received wavelength division multiplexing (WDM) signal. A frequency calibration unit generates a corresponding high-quality frequency reference light λ0, and then a frequency spreading unit generates a target optical carrier λ with a stable frequency difference from the high-quality reference light λ0. x .

[0171] like Figure 5 As shown, network node x receives a wavelength division multiplexed signal from the preceding node. This wavelength division multiplexed signal consists of three parts: one part needs to be resolved locally by Rx, one part needs to be passed through to the next network node, and the third part is used as an optical frequency reference.

[0172] Specifically, after acquiring a low-quality optical frequency reference λ0, Node x controls the wavelength λ0' of its local laser within a lockable range and uses a frequency calibration device to generate a high-quality reference light λ0. Subsequently, the wavelength λ used for transmitting its own data is determined through a frequency spreading unit and a frequency selection unit. x That is, the target optical carrier λ x After data modulation, it is combined with the wavelength reference signal λ0 and other signals passed through to the next network node, and then sent to the next network node. In this implementation, the transmission of the wavelength reference is completed, and λ0... x The stable frequency difference from the λ0 wavelength reference is fixed. As the optical signal is transmitted, all network nodes will undergo frequency calibration, ultimately achieving full network wavelength synchronization.

[0173] It should be noted that the source of the optical signal differs in different application scenarios. For a tree topology, the optical signal λ0 originates from the signal transmitted by the preceding node. Examples include the downlink signal sent from the Optical Line Terminal (OLT) to the Optical Network Unit (ONU) in a Wavelength Division Multiplexing Passive Optical Fiber (WDM-PON) network, and the signal sent from the root node to the leaf nodes in a data center (DC). For a ring topology, the optical signal λ0 originates from the signal of the preceding node. Furthermore, the optical signal λ0 can take various forms, including at least one of continuous light, low-speed intensity modulated light, and low-order coherent modulated light.

[0174] Figure 6 This is a schematic diagram illustrating the working principle of the wavelength calibration device applicable to this application. For example... Figure 6 As shown, it mainly consists of three parts: a frequency calibration unit, a frequency expansion unit, and a frequency selection unit.

[0175] The frequency calibration unit is used to adjust the output wavelength λ0' of the local laser based on the reference light λ0 signal in order to generate high-quality reference light, which refers to a continuous light signal with a wavelength of λ0.

[0176] It should be noted that the structure of the frequency calibration unit needs to be adapted to the form of the reference light λ0. For example, when the reference light λ0 is a continuous DC light, wavelength locking or injection locking techniques are used. When the reference light λ0 is a low-order coherent modulated light, the laser frequency needs to be adjusted by extracting the phase difference feedback to achieve optical frequency calibration, such as with an optical phase-locked loop (PLL) scheme.

[0177] The function of the frequency spreading unit is to spread the optical frequency based on the reference light λ0, generating multiple optical signals λ with a stable frequency difference from the reference light λ0. x For example, this can be achieved using optical frequency combing technology. First, each spectral line has a fixed frequency difference from the reference light. Second, optical frequency combing technology can achieve a large frequency difference, thus ensuring that the optical network system can operate over a wide wavelength range. Simultaneously, this technology also enables small-particle frequency tunability and integrated miniaturization. For example, there are currently technologies for generating optical frequency combs on-chip (e.g., semiconductor mode-locked lasers, nonlinear photonic chips, etc.).

[0178] The function of the frequency selection unit is to select the target optical carrier λ x The optical frequency comb is filtered and amplified to serve as the carrier for transmitting data. In the embodiments of this application, injection-locked technology (IL) can be used, or tunable optical filters and optical amplifiers can be employed.

[0179] It should be understood that the tunable function of the frequency selection unit can ensure that each network node can flexibly generate an adaptive operating wavelength.

[0180] Figure 7 This is a schematic diagram of an example of an optical frequency calibration device applicable to this application. For example... Figure 7 As shown, the reference light λ0 is in the form of continuous DC light, interpolated into the received wavelength division multiplexing (WDM) spectrum. The form of continuous DC light is the easiest to extract the wavelength reference from.

[0181] Specifically, the wavelength division multiplexing (WDM) spectrum is filtered and the reference light λ0 is extracted after passing through an optical band pass filter (OBPF). In this embodiment, a fiber bragg grating (FBG) that meets the wavelength matching condition is used to achieve this function. That is, the reference light λ0 takes the reflection path, while the remaining spectrum passes through the FBG for demodulation or continued transmission.

[0182] In the frequency calibration unit, the received reference light λ0 is injected into the local laser through ports 1 and 2 of the circulator, making the wavelength of the local laser's output light signal close to the wavelength of the reference light λ0. The local laser then inputs the adjusted light signal, i.e., the high-quality reference light λ0, into port 3. At this point, the reference light is split into two through port 3. One part provides a feedback signal, which, through a frequency difference capture circuit, controls the wavelength λ0' of the local laser within a lockable range by the microprocessor (micro controller unit, MCU). The injection locking technology IL amplifies the injected wavelength while suppressing other sidebands, equivalent to active, extremely narrow bandwidth filtering. The other part is output to the frequency expansion unit. In this implementation, the high-quality reference light λ0 output from port 3 is at the same frequency as the reference light λ0. Furthermore, because this device has a tracking function, frequency calibration can be achieved even if the reference light drifts.

[0183] In the frequency spreading unit, the reference light λ0 is injected into a low-Vπ optical phase modulator (PM), driven by a sinusoidal signal. To ensure frequency consistency across different network nodes, the clock frequency is first extracted from the received data using clock data recovery (CDR), and then converted to generate the corresponding sinusoidal signal. According to the principle of the optical phase modulator, when the peak-to-peak value of the injected sinusoidal signal is large, the optical phase modulator outputs multiple spectral lines, with the interval between each line equal to the sinusoidal frequency, i.e., the interval of the optical frequency comb. When the output of the optical phase modulator is injected into the nonlinear photonic chip, the photonic chip achieves ultra-wide frequency spreading based on the four-wave mixing effect. Among the multiple optical carriers generated by the frequency spreading unit with a fixed frequency difference from the reference light λ0, the target optical carrier λ is included. x Each spectral line is phase-locked and has a stable frequency difference.

[0184] In the frequency selection unit, injection-locking technology is used to extract the target optical signal λ from the broadband optical frequency comb. x The specific process is as follows: a broadband optical frequency comb is injected into the local laser through ports 1 and 2 of the circulator, while the wavelength of the local laser is tuned to λ using the MCU. x Within the locked range, due to the principle of injection locking technology, the laser ultimately produces a standard λ. x Light is output through port 3 of the circulator. Finally, it is emitted using λ. x As a carrier wave, it modulates the data. This can be achieved by adjusting λ. x It allows for flexible selection of the operating wavelength for each network node.

[0185] In summary, this implementation allows the optical frequency calibration device to achieve wavelength calibration while ensuring that each node can flexibly generate its own operating wavelength. Furthermore, the wavelength allocation of the optical network system offers greater flexibility.

[0186] Figure 8 This is another schematic diagram of an optical frequency calibration unit applicable to this application. Figure 7 Unlike the optical frequency calibration device shown, the reference light λ0 in this implementation can be loaded with a low-speed data signal.

[0187] When loading data using intensity modulation, the frequency calibration section should employ methods such as... Figure 8 The structure shown is based on the same principle as a balanced phase-locked loop.

[0188] First, the reference light λ0 signal is filtered out using an optical bandpass filter. Then, the wavelength of the local laser is tuned to near λ0, effectively acting as a local oscillator. The reference light λ0 and the output optical signal of the local laser are then coupled together using a coupler. The coupled optical signal enters a balanced detector for signal detection. Since the intensity-modulated signal itself contains a large carrier capability, the output signal of the balanced detector includes the phase difference generated after the signal carrier and the local oscillator are coherently received. This phase difference is passed through a loop filter and fed back to the local oscillator laser, thereby achieving optical carrier synchronization—that is, synchronizing the wavelength of the local laser with the reference wavelength. Simultaneously, the output signal of the balanced detector, after further demodulation, allows data recovery.

[0189] Optionally, in this implementation, the frequency spreading unit and frequency selection unit in the wavelength calibration device can be used with... Figure 7 The same structure is not specifically limited in this application.

[0190] In summary, this implementation allows for frequency calibration using reference optical modulation data. This enables the transmission of low-speed control signaling via λ0, improving resource utilization.

[0191] Figure 9 This is yet another schematic diagram of an optical frequency calibration unit applicable to this application. (And...) Figure 7 Unlike the optical frequency calibration device shown, this implementation can load a low-speed data signal onto the reference light λ0. Modulating data based on the reference light λ0 can further improve resource utilization. Compared to... Figure 8 The intensity modulation method is adopted, which uses low-order coherent modulation to achieve higher signaling data transmission rates and improve the transmission quality of signaling data.

[0192] When loading data using low-order coherent modulation, the frequency calibration section should employ methods such as... Figure 9 The structure shown is based on the same principle as the Costas phase-locked loop.

[0193] First, the reference light λ0 signal is filtered out using an optical bandpass filter. Then, the wavelength of the local laser is tuned to near λ0, equivalent to a local oscillator. The reference light λ0 and the output light signal of the local laser are then input together into a 90° optical mixer. Output ports 1 and 2 of the optical mixer are fed into balanced receiver 1 to obtain the in-phase component of the signal. Output ports 3 and 4 of the optical mixer are fed into balanced receiver 2 to obtain the quadrature component of the signal. Based on the in-phase and quadrature components, a frequency difference acquisition circuit is used to extract the frequency difference. This frequency difference is passed through a voltage-controlled oscillator and fed back to a phase modulator to adjust the phase of the local laser. After the optical network system stabilizes, the local laser will output a local oscillator light signal with the same frequency as the reference light λ0, thus completing data demodulation.

[0194] It should be noted that a portion of the output optical signal of the local laser, λ0, will be split as a reference beam for use in subsequent frequency extension modules.

[0195] To achieve high-quality error extraction, low-order coherent modulation methods such as binary phase shift keying (BPSK) or quadrature phase shift keying (QPSK) can be used in the embodiments of this application.

[0196] Optionally, in this implementation, the frequency spreading unit and frequency selection unit in the wavelength calibration device can be used with... Figure 7 The same structure is not specifically limited in this application.

[0197] In summary, in this implementation, the optical frequency calibration device can achieve higher-speed signaling data transmission and improve the transmission quality of signaling data.

[0198] Figure 10 This is a schematic diagram of an optical frequency selection unit applicable to this application. For example... Figure 10 As shown, in the frequency selection unit, the frequency selection function can be achieved by using the technique of cascading an optical amplifier with an optical filter.

[0199] For example, firstly, a tunable optical filter is used to filter out the desired target optical carrier λ from the frequency comb. x Then, an optical amplifier is used to increase the optical power, outputting the target optical carrier λ. x Finally, the target optical carrier λ x The optical signal is modulated in the optical modulator after entering the optical module.

[0200] Alternatively, in this implementation, the frequency spreading unit in the wavelength calibration device can be used with... Figure 6 The same structure. The frequency calibration unit can be used for different purposes depending on the form of the reference light. Figure 7 (DC continuous light) Figure 8 (Low-speed intensity modulated light) and Figure 9 (Low-order coherent modulated light) has the same structure. This application does not specifically limit this.

[0201] Figure 11 This is yet another schematic diagram of an optical frequency calibration device applicable to this application. (As described above) Figures 7 to 10 The provided optical frequency calibration device differs in that the reference light is in the form of a dual-wavelength light, with wavelengths of λ0 and λ0+Δf. That is, two spectral lines are input, with a frequency interval of Δf, to generate the reference input RF signal for the optical frequency comb, which is the frequency difference between two adjacent spectral lines in the optical frequency comb. This implementation ensures the synchronization of the electrical clock of each network node.

[0202] Specifically, such as Figure 11 As shown, each network node filters two reference spectral lines, λ0 and λ0+Δf, from the received WDM signal using an optical bandpass filter (OBPF). Since the frequency difference between these two reference spectral lines is small, they can pass through the OBPF simultaneously. Then, an optical power divider splits these two reference spectral lines into two, which are injected into two frequency calibration devices. At this point, the input to the frequency calibration device is two spectral lines, corresponding to λ0 and λ0+Δf respectively. Active filtering injection locking is used to track these two spectral lines. Specifically, in frequency calibration device 1, the output wavelength of local laser 1 is adjusted according to the reference light with wavelength λ0, i.e., the optical frequency of the local laser is tuned to λ0. In frequency calibration device 2, the output wavelength of local laser 2 is adjusted according to the reference light with wavelength λ0+Δf, i.e., the optical frequency of local laser 2 is tuned to λ0+Δf. The specific frequency calibration process can be found in [reference needed]. Figure 7 The implementation methods shown are omitted here for simplicity. In summary, frequency calibration device 1 can generate a high-quality reference optical signal λ0 with the same frequency as the reference light λ0, and frequency calibration device 2 can generate a high-quality reference optical signal λ0+Δf with the same frequency as the reference light λ0+Δf.

[0203] This process is equivalent to active filtering, which also suppresses phase noise generated by the reference light during transmission. The output optical signal λ0 of frequency calibration device 1 is split into two by an optical power divider; one part is used as the beat frequency, and the other part is used as the input to the phase modulator. The output optical signal λ0+Δf of frequency calibration device 2 is coupled to λ0 through a coupler and then input to a photodetector (e.g., a photodiode). That is, the optical signal with wavelength λ0+Δf output by local laser 2 is used to beat with a portion of the reference light with wavelength λ0 output by local laser 1 to obtain an electrical signal with frequency Δf. According to the principle of square-law detection, the electrical signal output by the photodetector is exactly a sine wave signal with frequency Δf. This sine wave signal is input to the phase modulator PM to generate the seed light for the optical frequency comb. Finally, a wider optical frequency comb is realized using a nonlinear photonic chip.

[0204] Figure 11 The device shown provides both a wavelength reference and a frequency reference for the electrical signal. Figure 7 Compared to the method shown for recovering the clock from the data and then extracting the wavelength reference, the circuit structure of this implementation is simpler.

[0205] In summary, this application provides a method and apparatus for full-network wavelength calibration, which can improve spectrum utilization efficiency and network flexibility. Specifically, this is achieved through the joint operation of various units in the frequency calibration apparatus: the frequency calibration unit utilizes frequency-locked phase-locked technology to generate high-quality reference light based on the reference light, and can adapt to various reference light formats. The frequency spreading unit utilizes the phase-locked relationship of each spectral line in the optical frequency comb to achieve high-precision frequency spreading of the reference light. The frequency selection unit is tunable, enabling each network node to flexibly generate adaptive operating wavelengths.

[0206] The method and apparatus for network-wide wavelength calibration provided in this application employ a unified wavelength reference, thereby ensuring network-wide wavelength synchronization and improving spectrum utilization efficiency and network flexibility. From a transmission performance perspective, it avoids spectral aliasing between signals, improving signal transmission quality. From a network resource allocation perspective, it enables flexible allocation of spectrum resources with fine granularity, reducing guard bands, further releasing system margins, and improving spectrum utilization. From a hardware deployment perspective, it achieves colorless operation, with continuously adjustable wavelengths for each node and flexible configuration.

[0207] The above text combined Figures 1 to 11 The wavelength calibration method of this application is described in detail below, along with its embodiments. Figure 12 and Figure 13 This document describes in detail the apparatus-side embodiments of wavelength calibration according to this application. It should be understood that the descriptions of the apparatus embodiments correspond to the descriptions of the method embodiments. Therefore, any parts not described in detail can be found in the foregoing method embodiments.

[0208] Figure 12 This is a schematic block diagram of the wavelength calibration device provided in the embodiments of this application. Figure 12 As shown, the device 1000 may include a processing unit 1100, a transceiver unit 1200, a frequency calibration unit 1300, a frequency expansion unit 1400, and a frequency selection unit 1500.

[0209] It should be understood that the device 1000 may include tools for performing Figure 4 The unit of method 400 in the apparatus 1000. Furthermore, each unit in the apparatus 1000 and the other operations and / or functions described above are respectively for implementing... Figure 4 The corresponding process of method 400 in the middle.

[0210] For example, a processing unit is used to acquire a reference optical signal;

[0211] The frequency calibration unit is used to adjust the output wavelength of the local laser according to the reference optical signal to generate a reference optical signal with the same wavelength as the reference optical signal.

[0212] The frequency spreading unit is used to generate multiple target optical signals based on the reference optical signal. Each target optical signal has a different wavelength, and the frequency difference between each target optical signal and the reference optical signal is different and fixed.

[0213] The frequency selection unit is used to extract the first target optical signal from multiple target optical signals for data transmission.

[0214] Optionally, the transceiver unit is used to receive a first signal, which is an optical signal received by the current network node from the previous network node.

[0215] The processing unit is also used to filter and extract the reference optical signal from the first signal.

[0216] It should also be understood that the transceiver unit 1200 in the device 1000 can be implemented by a transceiver, and the processing unit 1100 in the device 1000 can be implemented by at least one processor.

[0217] It should also be understood that the transceiver unit 1200 in the device 1000 can be implemented through input / output interfaces, circuits, etc., and the processing unit 1100 in the device 1000 can be implemented through a processor, microprocessor, or integrated circuit integrated on the chip or chip system.

[0218] Figure 13 This is another schematic block diagram of the tracking compensation device 2000 provided in the embodiments of this application. For example... Figure 13As shown, the device 2000 includes a processor 2010, a transceiver 2020, and a memory 2030. The processor 2010, transceiver 2020, and memory 2030 communicate with each other via an internal connection. The memory 2030 stores instructions, and the processor 2010 executes the instructions stored in the memory 2030 to control the transceiver 2020 to transmit and / or receive signals.

[0219] It should be understood that the device 2000 can be used to perform the various steps and / or processes in the above method embodiments.

[0220] Optionally, the memory 2030 may include read-only memory and random access memory, and provide instructions and data to the processor. A portion of the memory may also include non-volatile random access memory. The memory 2030 may be a separate device or integrated into the processor 2010. The processor 2010 may be used to execute instructions stored in the memory 2030, and when the processor 2010 executes instructions stored in the memory, the processor 2010 is used to perform the various steps and / or processes of the above method embodiments.

[0221] The transceiver 2020 may include a transmitter and a receiver. The processor 2010 and memory 2030 may be integrated with the transceiver 2020 on different chips. For example, the processor 2010 and memory 2030 may be integrated in a baseband chip, and the transceiver 2020 may be integrated in a radio frequency chip. Alternatively, the processor 2010 and memory 2030 may be integrated with the transceiver 2020 on the same chip. This application does not limit this.

[0222] The transceiver 2020 can also be a communication interface, such as an input / output interface or circuit. The transceiver 2020, processor 2010, and memory 2020 can all be integrated into the same chip, such as within a baseband chip.

[0223] It should be understood that the specific examples in the embodiments of this application are only to help those skilled in the art better understand the technical solutions of this application, and the above specific implementation methods can be considered as the optimal implementation methods of this application, rather than limiting the scope of the embodiments of this application.

[0224] It should also be understood that, in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0225] It should be understood that the above embodiments are merely illustrative of the wavelength calibration method provided in this application and do not constitute any limitation on the scope of protection of this application.

[0226] It should also be understood that, in the various embodiments of this application, unless otherwise specified or logically conflicting, the terminology and / or descriptions between different embodiments may be consistent and may reference each other. Technical features in different embodiments may be combined to form new embodiments based on their inherent logical relationships. It should be understood that, in the embodiments of this application, the processor may be a central processing unit (CPU), or it may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0227] It should also be understood that the memory in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM). It should be noted that the memory used in the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0228] The method steps in the embodiments of this application can be implemented in hardware or by a processor executing software instructions. The software instructions can consist of corresponding software modules, which can be stored in random access memory, flash memory, read-only memory, programmable read-only memory, erasable programmable read-only memory, electrically erasable programmable read-only memory, registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. Exemplarily, the storage medium is coupled to the processor, enabling the processor to read information from and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and storage medium can reside in an ASIC. Additionally, the ASIC can reside in a network node. Alternatively, the processor and storage medium can exist as discrete components in the network node.

[0229] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the processes or functions described in the embodiments of this application are performed entirely or partially. The computer can be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user equipment, or other programmable device. The computer program or instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another. For example, the computer program or instructions can be transferred from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, such as a floppy disk, hard disk, or magnetic tape; it can also be an optical medium, such as a digital video optical disc; or it can be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both types of storage media.

[0230] It should be understood that in the above embodiments, each embodiment can be an independent solution or a combination thereof according to its internal logic, and all such solutions fall within the protection scope of this application. Network nodes can execute some or all of the steps in each embodiment. These steps or operations are merely examples, and this application can also perform other operations or variations thereof. Furthermore, the steps can be executed in different orders as presented in the embodiments, and it is not necessary to execute all the operations in the embodiments of this application.

[0231] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0232] As used in this specification, the terms "component," "module," "system," etc., are used to refer to computer-related entities, hardware, firmware, combinations of hardware and software, software, or software in execution. For example, a component can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, and / or a computer. As illustrated, applications running on computing devices and computing devices can both be components. One or more components may reside in a process and / or an execution thread, and components may be located on a single computer and / or distributed among two or more computers. Furthermore, these components can be executed from various computer-readable media on which various data structures are stored. Components can communicate, for example, via local and / or remote processes based on signals having one or more data packets (e.g., data from two components interacting with another component between a local system, a distributed system, and / or a network, such as the Internet interacting with other systems via signals).

[0233] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0234] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0235] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0236] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0237] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0238] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion 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 described in the various embodiments of this application. 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.

[0239] The above description is merely a specific embodiment of this application, but the scope of protection of this application 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 application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A wavelength calibration method, characterized in that, The method is applied to a network with a specific topology, and is executed by each network node in the network. The method includes: Acquire the reference optical signal; The output wavelength of the local laser is adjusted according to the reference optical signal to generate a reference optical signal, the reference optical signal having the same wavelength as the reference optical signal; Multiple target optical signals are generated based on the reference optical signal. Each of the multiple target optical signals has a different wavelength, and the frequency difference between each target optical signal and the reference optical signal is different and fixed. The first target optical signal is extracted from the plurality of target optical signals for data transmission.

2. The method according to claim 1, characterized in that, The acquisition of the reference optical signal includes: Receive a first signal, wherein the first signal is an optical signal received by the current network node from the previous network node of the current network node; The reference optical signal is extracted by filtering from the first signal.

3. The method according to claim 1 or 2, characterized in that, The reference optical signal can be in the form of one of the following: DC continuous light, low-speed intensity modulated continuous light, or low-order coherent modulated continuous light.

4. The method according to claim 3, characterized in that, The step of adjusting the output wavelength of the local laser according to the reference optical signal to generate a reference optical signal includes: When the reference optical signal is in the form of DC continuous light, the output wavelength of the local laser is adjusted according to wavelength locking technology or injection locking technology to generate a reference optical signal.

5. The method according to claim 3, characterized in that, The step of adjusting the output wavelength of the local laser according to the reference optical signal to generate a reference optical signal includes: When the reference optical signal is in the form of low-speed intensity modulated continuous light, the reference optical signal is coupled to the output optical signal input coupler of the local laser; The coupled optical signal is input into a balanced detector to obtain the phase difference; The optical frequency of the local laser is adjusted according to the phase difference feedback to generate the reference optical signal.

6. The method according to claim 3, characterized in that, The step of adjusting the output wavelength of the local laser according to the reference optical signal to generate a reference optical signal includes: When the reference optical signal is in the form of low-order coherent modulated continuous light, the reference optical signal and the output optical signal of the local laser are input into a 90° optical mixer to obtain the in-phase component and quadrature component of the optical signal. The phase difference of the optical signal is determined based on the in-phase and quadrature components of the optical signal; The optical frequency of the local laser is adjusted based on the phase difference of the optical signal to generate the reference optical signal.

7. The method according to claim 1 or 2, characterized in that, When the reference optical signal is in the form of a dual-wavelength light, and the wavelengths of the dual-wavelength light are λ0 and λ0+Δf, the method further includes: The output wavelength of the first local laser is adjusted according to the reference optical signal with wavelength λ0 to generate a reference optical signal with wavelength λ0. The output wavelength of the second local laser is adjusted according to a reference optical signal with wavelength λ0+Δf to generate an optical signal with wavelength λ0+Δf. The optical signal with wavelength λ0+Δf output by the second local laser is used to beat a portion of the optical signal of the reference light with wavelength λ0 output by the first local laser to obtain an electrical signal with frequency Δf.

8. The method according to claim 2, characterized in that, The method further includes: The first target optical signal is loaded with data and coupled with the reference optical signal and the second signal before being sent to the next network node. The second signal is the optical signal in the first signal that is directly transmitted to the next network node.

9. A wavelength calibration device, characterized in that, The device is applied to a network with a topology, and the device is applied to each network node in the network with the topology. The device includes: Processing unit, used to acquire reference optical signal; A frequency calibration unit is used to adjust the output wavelength of the local laser according to the reference optical signal to generate a reference optical signal, wherein the reference optical signal has the same wavelength as the reference optical signal. A frequency spreading unit is used to generate multiple target optical signals based on the reference optical signal. Each of the multiple target optical signals has a different wavelength, and the frequency difference between each target optical signal and the reference optical signal is different and fixed. A frequency selection unit is used to extract a first target optical signal from the plurality of target optical signals for data transmission.

10. The apparatus according to claim 9, characterized in that, The device further includes: A transceiver unit is used to receive a first signal, which is an optical signal received by the current network node from the previous network node of the current network node. The processing unit is further configured to filter and extract the reference optical signal from the first signal.

11. The apparatus according to claim 9 or 10, characterized in that, The reference optical signal can be in the form of one of the following: DC continuous light, low-speed intensity modulated continuous light, or low-order coherent modulated continuous light.

12. The apparatus according to claim 11, characterized in that, When the reference optical signal is in the form of DC continuous light The frequency calibration unit is also used to adjust the output wavelength of the local laser according to wavelength locking technology or injection locking technology to generate a reference optical signal.

13. The apparatus according to claim 11, characterized in that, When the reference optical signal is in the form of low-speed intensity modulated continuous light... The frequency calibration unit is also used to couple the reference optical signal to the output optical signal input coupler of the local laser; The coupled optical signal is input into a balanced detector to obtain the phase difference; The optical frequency of the local laser is adjusted according to the phase difference feedback to generate the reference optical signal.

14. The apparatus according to claim 11, characterized in that, When the reference optical signal is in the form of low-order coherent modulated continuous light... The frequency calibration unit is also used to input the reference optical signal and the output optical signal of the local laser into a 90° optical mixer to obtain the in-phase component and quadrature component of the optical signal. The phase difference of the optical signal is determined based on the in-phase and quadrature components of the optical signal; The optical frequency of the local laser is adjusted based on the phase difference of the optical signal to generate the reference optical signal.

15. The apparatus according to claim 9 or 10, characterized in that, When the reference optical signal is in the form of a dual-wavelength light, the wavelengths of the dual-wavelength light are λ0 and λ0+Δf, The frequency calibration unit is also used to adjust the output wavelength of the first local laser according to the reference optical signal with wavelength λ0, so as to generate a reference optical signal with wavelength λ0. The frequency calibration unit is further configured to adjust the output wavelength of the second local laser according to the reference optical signal with wavelength λ0+Δf to generate an optical signal with wavelength λ0+Δf. The optical signal with wavelength λ0+Δf output by the second local laser is used to beat with a portion of the optical signal of the reference light with wavelength λ0 output by the first local laser to obtain an electrical signal with frequency Δf.

16. The apparatus according to claim 10, characterized in that, The transceiver unit is further configured to load data onto the first target optical signal through the processing unit, and then couple it with the reference optical signal and the second signal before sending it to the next network node, wherein the second signal is the optical signal in the first signal that is directly transmitted to the next network node.

17. A communication device, characterized in that, include: A processor and an interface circuit, the interface circuit being configured to receive signals from other communication devices besides the communication device and transmit them to the processor, or to send signals from the processor to other communication devices besides the communication device, the processor implementing the method as described in any one of claims 1 to 8 in the communication device via logic circuits or execution code instructions.

18. A flexible optical network system, characterized in that, The elastic optical network includes a first network node, which includes a wavelength calibration device as described in any one of claims 9 to 16 or a communication device as described in claim 17.

19. A chip, characterized in that, include: A processor for retrieving and running a computer program from memory, causing the chip mounted thereon to perform the method as described in any one of claims 1 to 8.

20. A computer storage medium, characterized in that, The computer storage medium stores computer instructions, which, when executed on the computer, cause the computer to perform the method as described in any one of claims 1 to 8.

21. A computer program product, characterized in that, When the computer program code or instructions are executed on a computer, the computer causes the computer to perform the method as described in any one of claims 1 to 8.

Images