An optical channel monitor and monitoring method

Abstract

The application discloses an optical channel monitor and a monitoring method, and relates to the technical field of optical channel monitoring.The optical channel monitor comprises a photodetector, a signal processor and a spectrum modulation chip.The spectrum modulation chip comprises an optical input port, an optical output port group and a spectrum disturbance structure.The optical output port group comprises at least one optical output port.The spectrum disturbance structure is used for receiving an input optical signal input through the optical input port, performing disturbance processing on the input optical signal, obtaining a plurality of output optical signals with different optical characteristics, and outputting through the optical output port group.The photodetector is used for converting the optical power of the output optical signal into a corresponding electrical signal.The signal processor is used for obtaining relevant data of the spectrum of the input optical signal according to the plurality of output optical signals.Compared with the traditional mode, the application has the advantages of high speed, high resolution, low cost, small size and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of optical channel monitoring, and in particular to an optical channel monitor and a monitoring method. Background Art

[0002] Wavelength division multiplexing (WDM) is a technology that combines multiple optical signals of different wavelengths through a combiner and couples them into the same optical fiber for data transmission. This technology can increase the transmission capacity of optical fibers and improve the utilization efficiency of optical fiber resources. In the early days of this technology, due to limited technical conditions, the wavelength spacing was controlled at tens of nanometers. This relatively dispersed WDM is called sparse WDM, or CWDM (Coarse WDM). Later, as the technology became more advanced, the wavelength spacing was compressed to a few nanometers, becoming a compact WDM called dense WDM (DWDM).

[0003] The channel spacing in communication networks using DWDM technology is getting smaller and smaller, gradually shrinking from 200 GHz to 100 GHz, 50 GHz, and even 25 GHz. The number of channels is increasing, and the speed is constantly improving. To ensure the stable and efficient operation of the communication network, the wavelength, power, and signal-to-noise ratio of each optical channel signal must be monitored at key nodes.

[0004] Common optical channel monitors are mainly categorized as spectroscopic and tunable filter types. Tunable filter-based optical channel monitors are primarily categorized into Michelson interferometers, Fabry-Perot interferometers, and dielectric film filters. The basic structure and operating principle of a tunable filter-based optical channel monitor are as follows: an optical signal enters the filter, which filters and outputs only signals within a specific wavelength range. This signal is then received by a detector. Through tuning, the filter's passband wavelength continuously changes, ultimately covering the entire bandwidth range. This type of optical channel monitor is compact, eliminates the inter-channel interference caused by spectroscopic analysis, and requires only a single detector. However, existing filters lack resolution, have slow modulation rates, and exhibit slow spectral scanning rates, making real-time signal monitoring impossible. Furthermore, due to their immaturity, their cost remains high. Summary of the Invention

[0005] The present invention aims to address, to a certain extent, one of the technical problems in the related art. To this end, the present invention provides an optical channel monitor and monitoring method that utilizes the principles of a computational reconstruction spectrometer to monitor the optical channel. This device can be integrated into a spectral modulation chip, reducing size and cost while enabling wide-spectrum monitoring of optical signals with high speed and resolution.

[0006] In order to achieve the above object, the present application adopts the following technical scheme in the first aspect:

[0007] An optical channel monitor comprises a photodetector and a signal processor, and further comprises a spectrum modulation chip; the spectrum modulation chip comprises an optical input port, an optical output port group and a spectrum perturbation structure, the optical output port group comprises at least one optical output port, the spectrum perturbation structure is used for receiving an input optical signal input through the optical input port, and performing perturbation processing on the input optical signal to obtain a plurality of output optical signals with different optical characteristics and output through the optical output port group; the photodetector is used for converting optical power of the output optical signal into a corresponding electrical signal; and the signal processor is used for obtaining relevant data of a spectrum of the input optical signal according to the plurality of output optical signals.

[0008] Optionally, the spectrum perturbation structure comprises a plurality of cascaded active tunable spectrum perturbation units, the signal processor is further used for generating a control signal; the optical output port group comprises the optical output port; and the plurality of cascaded active tunable spectrum perturbation units generate different perturbations in time sequence according to tuning of the control signal, so that the optical output port outputs a plurality of different output optical signals at different time points.

[0009] Optionally, the spectrum perturbation structure comprises a plurality of optical path components, the plurality of optical path components are connected with the optical input port through an optical splitter, each of the optical path components comprises a plurality of cascaded passive spectrum perturbation units, the plurality of passive spectrum perturbation units in different optical path components have different spectrum responses, so that the plurality of optical path components generate different perturbations on the input optical signal; the optical output port group comprises a plurality of optical output ports, the plurality of optical output ports correspond to the plurality of optical path components one by one, and output a plurality of different output optical signals; and power distributions of different output optical signals in a frequency domain are different.

[0010] Optionally, the spectrum perturbation structure comprises a plurality of optical path components, the plurality of optical path components are connected with the optical input port through an optical splitter; the optical path component comprises a plurality of cascaded spectrum perturbation units, the plurality of spectrum perturbation units in different optical path components have different spectrum responses, so that the plurality of optical path components generate different perturbations on the input optical signal, wherein the plurality of cascaded spectrum perturbation units of at least one optical path component are a plurality of cascaded active tunable spectrum perturbation units; the signal processor is further used for providing a control signal for tuning of the active tunable spectrum perturbation units; and the optical output port group comprises a plurality of optical output ports, the plurality of optical output ports correspond to the plurality of optical path components one by one, to output different output optical signals.

[0011] Optionally, at least one of the active tunable spectral perturbation units in the spectral perturbation structure is an active asymmetric Mach-Zehnder interferometer, wherein the active asymmetric Mach-Zehnder interferometer has two tuning arms of unequal lengths and a phase modulator arranged on at least one of the tuning arms, wherein the phase modulator tunes the phase of the optical signal entering the tuning arm according to the control signal to adjust the power distribution of the output optical signal in the frequency domain.

[0012] Optionally, there is an arm length difference between two tuning arms of the active asymmetric Mach-Zehnder interferometer; and a plurality of active asymmetric Mach-Zehnder interferometers have different arm length differences.

[0013] Optionally, at least one of the active tunable spectral perturbation units in the spectral perturbation structure is a microring filter with a resonant structure, and a phase modulator is provided in the resonant structure of the microring filter. The phase modulator tunes the phase of the optical signal entering the resonant structure according to the control signal to adjust the power distribution of the output optical signal in the frequency domain.

[0014] Optionally, the microrings of the plurality of microring filters have different circumferences.

[0015] Optionally, the passive spectrum perturbation unit or at least one of the spectrum perturbation units in the spectrum perturbation structure is a passive asymmetric Mach-Zehnder interferometer or a microring filter with a resonant structure.

[0016] In addition, the present invention also provides an optical channel monitoring method in a second aspect, including: obtaining multiple different output optical signals corresponding to the input optical signal; performing spectral calculation and reconstruction on the input optical signal based on the multiple different output optical signals; and obtaining the spectrum of the input optical signal.

[0017] Optionally, before the step of obtaining a plurality of different output optical signals corresponding to the input optical signal, the method further includes sending a control signal to the spectrum modulation chip; wherein the number of the plurality of different output optical signals is related to the control signal.

[0018] These features and advantages of the present invention will be further disclosed in the following detailed description and accompanying drawings. The preferred embodiments and means of the present invention will be fully illustrated in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of the present invention. Furthermore, although multiple features, elements, and components may be present in each of the following text and accompanying drawings, they may be labeled with different symbols or numbers for convenience, but all represent components with the same or similar structure or function. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described below in conjunction with the accompanying drawings:

[0020] Figure 1 2 is a principle block diagram of the optical channel monitor described in this embodiment.

[0021] Figure 2 This is a structural block diagram of the spectral modulation chip described in this embodiment.

[0022] Figure 3 Schematic diagram of the structure of the spectrum modulation chip described in this embodiment, showing the time-domain adjustable spectrum perturbation structure therein.

[0023] Figure 4 Schematic diagram of the structure of the time-domain adjustable spectral perturbation structure in this embodiment, showing the active asymmetric Mach-Zehnder interferometer therein.

[0024] Figure 5 FIG. 4 is a schematic structural diagram of the time-domain adjustable spectrum perturbation structure described in this embodiment, showing a micro-ring filter with a resonant structure.

[0025] Figure 6 Schematic diagram of the structure of the time-domain adjustable spectral perturbation structure described in this embodiment, showing an active asymmetric Mach-Zehnder interferometer and a microring filter with a resonant structure.

[0026] Figure 7 Schematic diagram of the structure of the spectrum modulation chip described in this embodiment, showing the spatial spectrum perturbation structure therein.

[0027] Figure 8 Flowchart of the optical channel monitoring method described in this embodiment.

[0028] Figure 9 This is a diagram showing the spectrum reconstruction result of an optical signal with a 50 GHz channel spacing in the C band using the optical channel monitoring method in this embodiment.

[0029] Among them, 1. Asymmetric Mach-Zehnder interferometer; 12. Tuning arm; 2. Microring filter; 21. Resonant structure; 3. Phase modulator. DETAILED DESCRIPTION

[0030] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described in the embodiments are intended to explain the present invention and are not to be construed as limiting the present invention.

[0031] Reference in this specification to "one embodiment," "an example," or "an example" means that a particular feature, structure, or characteristic described in connection with the embodiment itself can be included in at least one embodiment of the present patent disclosure. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

[0032] Example:

[0033] like Figure 1 Figure 1 shows an optical channel monitor for monitoring optical signals within an optical channel in an optical transmission network system. The optical transmission network can be either a dense wavelength division multiplexing (DWDM) or coarse wavelength division multiplexing (CWDM) optical transmission network, without limitation. The optical channel monitor includes an optical waveguide, a spectrum modulation chip, a photodetector, and a signal processor.

[0034] The optical channel of the optical transmission network system is used to transmit multiplexed signals. A splitter is provided on the optical channel to separate an optical signal from the multiplexed signal for monitoring. One end of the optical waveguide is connected to the output of the splitter, and the other end is connected to the optical channel monitor, which receives the optical signal separated from the multiplexed signal.

[0035] Among them, such as Figure 2 As shown, the spectral modulation chip includes an optical input port, an optical output port group, and a spectrum perturbation structure. The optical input port is used to receive the optical signal of the optical channel through an optical waveguide; the spectrum perturbation structure is used to receive the input optical signal input through the optical input port and perform perturbation processing on the input optical signal to obtain multiple output optical signals with different optical characteristics, which are output through the optical output port group. The optical output port group includes at least one optical output port, and the multiple output optical signals can be output from the same optical output port or from different optical output ports.

[0036] Perturbation processing here refers to the process by which the optical characteristics of the input optical signal are altered according to a preset spectral response function after passing through the spectral perturbation structure during transmission, thereby changing the power distribution of the output optical signal in the frequency domain. The spectral perturbation structure achieves this by spatially and in parallel by distributing multiple spectral perturbation units with different spectral response functions (this type of spectral perturbation structure is referred to as a spatial spectral perturbation structure) or by distributing spectral perturbation units with adjustable spectral response functions in the time domain (this type of spectral perturbation structure is referred to as a time-domain adjustable spectral perturbation structure). This allows different output optical signals to have different power distributions in the frequency domain, i.e., each output optical signal is unique. The spectral response function can be achieved by designing different parameters of the spectral perturbation structure.

[0037] The perturbation processing can be one time or multiple times. When multiple perturbations are performed, different outputs are generated by setting parameters for each perturbation. With the superposition of the number of perturbations (including the order of perturbations under different parameters), the power distribution of each output optical signal in the frequency domain has high randomness, and the multiple output optical signals also have high uncorrelation. At the same time, in order to make the spectral perturbation structure change the power distribution of the output optical signal in the entire frequency domain (bandwidth), the bandwidth of the spectral perturbation structure is greater than or equal to the entire bandwidth of the optical signal.

[0038] The following is described with respect to a time-domain adjustable spectral perturbation structure and a spatial spectral perturbation structure, respectively.

[0039] As shown in Figure 3 , a time-domain adjustable spectral perturbation structure is shown, which includes three or more cascaded active tunable spectral perturbation units, and the optical output port group is provided with one optical output port. The multiple cascaded active tunable spectral perturbation units are arranged on the optical transmission path between the tube input port and the optical output port.

[0040] In this embodiment, the optical transmission path of the spectral perturbation structure is only taken as an example, and the number of optical transmission paths can be flexibly set by those skilled in the art according to actual conditions, as well as the corresponding number of cascaded active tunable spectral perturbation units and optical output ports, which are not limited here.

[0041] The multiple cascaded active tunable spectral perturbation units generate different perturbations in time sequence according to the tuning of the control signal, so that the optical output port outputs multiple different output optical signals at different times.

[0042] Specifically, as shown in Figure 4 , an embodiment of an active tunable spectral perturbation unit is shown, which is an active asymmetric Mach-Zehnder interferometer 1. The active asymmetric Mach-Zehnder interferometer has two tuning arms 12 with unequal lengths and at least one phase modulator 3 arranged on one of the tuning arms 12. The asymmetric Mach-Zehnder interferometer is composed of an asymmetric structure through two tuning arms with unequal lengths. The phase modulator actively tunes the phase of the optical signal entering the tuning arm according to the control signal, so as to adjust the power distribution of the output optical signal in the frequency domain.

[0043] Preferably, the phase modulator has at least three different phase adjustment states, so that the three Mach-Zehnder interferometers can make the optical output port group of the spectral perturbation structure output 27 different output optical signals.

[0044] It should be noted that there is an arm length difference between the two tuning arms of the active asymmetric Mach-Zehnder interferometer, and multiple active asymmetric Mach-Zehnder interferometers have different arm length differences. For example, the arm length differences between the two interferometer arms in a three-stage asymmetric Mach-Zehnder interferometer can be set to 300 μm, 500 μm, and 800 μm, respectively, to improve the random perturbation effect.

[0045] It should be noted that for DWDM (dense wavelength division multiplexing) channel monitoring applications, the arm length difference of the asymmetric Mach-Zehnder interferometer is between 300 and 2000 μm; for CWDM (coarse wavelength division multiplexing) channel monitoring applications, the arm length difference of the asymmetric Mach-Zehnder interferometer is between 100 and 1000 μm. Those skilled in the art can flexibly set the arm length difference according to actual conditions, and there is no limitation.

[0046] More specifically, the active asymmetric Mach-Zehnder interferometer further includes a first waveguide beam splitter element disposed on the input side of the tuning arm and a second waveguide beam splitter element disposed on the output side of the tuning arm. The first waveguide beam splitter element is configured to split the input optical signal into two paths according to a preset splitting ratio and input them into the two tuning arms, respectively. The second waveguide beam splitter element is configured to combine the output lights of the two tuning arms (also known as the interferometer arms) to generate optical interference (i.e., form a disturbance).

[0047] The splitting ratio of the first waveguide beam splitting element and the second waveguide beam splitting element is between 0.05 and 0.3. The splitting ratios of the first waveguide beam splitting element and the second waveguide beam splitting element in different Mach-Zehnder interferometers can be the same or different, without limitation.

[0048] In two adjacent asymmetric Mach-Zehnder interferometers, the output light of the second waveguide beam splitter element in the previous stage is completely used as the input light of the first waveguide beam splitter element in the next stage. It should be noted that in two adjacent asymmetric Mach-Zehnder interferometers, the second waveguide beam splitter element in the previous asymmetric Mach-Zehnder interferometer and the first waveguide beam splitter element in the next asymmetric Mach-Zehnder interferometer can reuse the same waveguide beam splitter element.

[0049] Specifically, such as Figure 5 FIG. 1 shows another embodiment of an active tunable spectral perturbation unit. The active tunable spectral perturbation unit comprises a microring filter 2 having a resonant structure 21. A phase modulator 3 is provided in the resonant structure of the microring filter. The phase modulator tunes the phase of the optical signal entering the resonant structure according to the control signal to adjust the power distribution of the output optical signal in the frequency domain. The microrings of the microring filters each have different circumferences.

[0050] It should be noted that for DWDM (dense wavelength division multiplexing) channel monitoring applications, the loop length of the microring resonant cavity (resonant structure) is between 150 and 2000 μm; for CWDM (coarse wavelength division multiplexing) channel monitoring applications, the loop length of the microring resonant cavity is between 100 and 1000 μm. Those skilled in the art can flexibly adjust the length based on actual conditions without limitation.

[0051] In addition, those skilled in the art can also combine the above two active tunable spectrum perturbation unit implementation schemes to obtain the following Figure 6 The structure in .

[0052] like Figure 7 The figure shows a spatial spectrum perturbation structure. The spectrum perturbation structure includes multiple optical path components, for example, 16, 32, or 64. The specific number can be adjusted according to the number and spacing of channels in the optical signal and is not limited. The multiple optical path components are connected to the optical input port via an optical splitter. The optical input port and the multiple optical path components are connected to each other via a 1*N splitter to achieve splitting and parallel connection, where N is the number of optical path components.

[0053] The optical path component includes three or more cascaded passive spectral perturbation units, wherein the multiple passive spectral perturbation units in different optical path components have different spectral responses, so that the multiple optical path components produce different perturbations on the input optical signal. The optical output port group includes multiple optical output ports, each corresponding one-to-one to the multiple optical path components, and outputting multiple different output optical signals, wherein the different output optical signals have different power distributions in the frequency domain.

[0054] Specifically, the passive spectral perturbation unit is a passive asymmetric Mach-Zehnder interferometer or a microring filter with a resonant structure. Unlike actively tunable spectral perturbation units, these lack phase modulators and cannot actively adjust perturbation parameters. Instead, they can only achieve the same effect as an actively tunable spectral perturbation unit by spatially splitting and paralleling a certain number of optical path components according to known design parameters during production.

[0055] It should be noted that those skilled in the art may also adopt a hybrid spectral perturbation structure, that is, an additional optical path component is provided in the spatial spectral perturbation structure. Unlike other optical path components, this optical path component includes multiple cascaded active tunable spectral perturbation units (for specific implementations, see the time-domain tunable spectral perturbation structure), thereby achieving a combination of the time-domain tunable spectral perturbation structure and the spatial spectral perturbation structure. Those skilled in the art can flexibly set the spectral perturbation structure according to actual conditions without limitation.

[0056] The photoelectric detector receives the high-random output optical signal output by the optical output port, and is used for converting the optical power of the output optical signal into a corresponding electrical signal. The photoelectric detector can correspond to one optical output port, or can be time-division multiplexed with one photoelectric detector, without limitation.

[0057] The photoelectric detector can be an InGaAs detector or a germanium detector. For the germanium detector, it can be integrated with the spectral modulation chip on the same monolithic chip, without limitation.

[0058] For only using a spatial type spectral disturbance structure, the signal processor has an input end and an output end. The input end receives the electrical signal corresponding to the output optical signal, and the output end outputs the required monitoring result after processing. The monitoring result can be a digital signal corresponding to the electrical signal, which records the spectral data of the output optical signal, or the spectrum of the input optical signal obtained after spectral calculation and reconstruction of the digital signal.

[0059] For the spectral disturbance structure containing a time-domain adjustable type, the signal processor further includes a control end electrically connected with the spectral disturbance structure, for controlling the phase modulator to complete different phase adjustments according to a preset control signal, so that the output port outputs different output optical signals.

[0060] It should be noted that the input end of the signal processor is used to process the output signal of the photoelectric detector (with signal amplification circuit, analog-to-digital conversion circuit, etc.). The signal processor can integrate the calculation function, and can be used for reconstructing and recovering the spectrum of the optical signal, without limitation. Similarly, the signal processor can be integrated with the photoelectric detector and the spectral modulation chip on the same monolithic chip.

[0061] For phase modulation through thermal tuning or electrical tuning, an electrical driving module needs to be arranged between the control end of the signal processor and the phase modulator.

[0062] It should be noted that the spectral modulation chip uses a planar optical waveguide chip, and the waveguide material of the chip includes silicon nitride waveguide, silicon waveguide, silicon oxide waveguide, thin film lithium niobate waveguide, polymer waveguide, etc. Based on the Mach-Zehnder interferometer and the micro-ring filter, the spectral disturbance structure can be manufactured on the chip.

[0063] The optical channel monitor in this embodiment uses the basic principle of a computational reconstruction spectrometer to monitor the optical signal in the optical channel. The basic principle of a computational reconstruction spectrometer is to import the input spectrum into multiple pre-calibrated wide-spectrum filter arrays (i.e., the spectral modulation chip in this embodiment, which can produce different spectral responses in time or space through tuning, and can also achieve the effect of a wide-spectrum filter array), and use a corresponding number of photodetectors to detect the light intensity of the filtered spectrum. This intensity information is used to construct an underdetermined set of equations, i.e., a spectral reconstruction matrix, and related algorithms, such as convex optimization algorithms, machine learning and other mathematical algorithms, are used to perform inverse solutions to obtain information about the input spectrum. The advantage of this method is that a smaller number of filters and photodetector groups can be used to solve a larger number of pixel points in the frequency domain of the spectrum, thereby effectively reducing the system volume, cost and computational complexity while achieving high spectral detection performance.

[0064] From a mathematical point of view, in order to achieve an ideal spectral detection effect, this type of filtering structure needs to meet the following two conditions: (1) the spectral response of each channel needs to have a small autocorrelation coefficient to achieve high resolution; (2) the channels need to have a small cross-correlation coefficient to ensure the independence of spectral sampling; only then can high-intensity random perturbations be generated in the frequency domain, so that an effective underdetermined set of equations (i.e., the spectral reconstruction matrix) can be constructed and solved when using a computational spectrometer.

[0065] The spectral modulation chip in this embodiment can generate different spectral responses through the spectral perturbation structure, resulting in a high-intensity random perturbation of the output spectrum in the frequency domain. Because the spectral perturbation structure includes phase modulators, each of which can modulate phases of varying magnitudes, by providing a reasonable number of spectral perturbation structures, as well as a reasonable number and adjustable positions of phase modulators, and arranging these in an orderly manner, the spectral modulation chip can generate different spectral responses in the time domain (equivalent to filters, where the number of filters far exceeds the number of equations in the underdetermined system).

[0066] The working principle of the optical channel monitor described in this embodiment (taking the time domain type as an example) is as follows: by designing the spectral perturbation structure of the spectral modulation chip as a cascade of multiple (microring) filter / (Mach-Zehnder) interferometer structures, each filter / interferometer can be modulated individually. After multi-stage filtering / interference, the input spectrum (optical signal) will be perturbed into a nearly irregular spectral output. Different modulation configurations (filters / interferometers) will have different perturbation characteristics and output spectra.

[0067] Its perturbation characteristics change each time the modulation configuration is changed. The output of each photodetector corresponds to one modulation. The perturbation characteristics under each modulation configuration, that is, the spectral response function, is Ti(λ) (i=1,2,...,M), where M is the number of modulations. The output of the photodetector is:

[0068] I t =∫T i (λ)Φ(λ)dλ

[0069] Multiple response functions can be recorded as a perturbation characteristic matrix, and multiple photodetector results can also be recorded as a column vector:

[0070] I M×1 =T M×N Φ N×1 , which is the spectral reconstruction matrix, or the underdetermined system of equations.

[0071] Where N is the number of wavelength pixels.

[0072] Given column vector I M×1 And the transfer characteristic matrix T M×N In the case of , the spectrum Φ of the input signal can be obtained by the reconstruction algorithm N×1 .

[0073] The designed spectral perturbation structure, combined with the corresponding reconstruction algorithm, only requires dozens to hundreds of modulations to reliably reconstruct the input spectrum with a wavelength resolution of tens of picometers.

[0074] At the same time, if Figure 8 As shown, the present embodiment in a second aspect also provides an optical channel monitoring method, including but not limited to the following steps.

[0075] S100: Sending a control signal to a spectrum modulation chip to obtain a plurality of different output optical signals corresponding to the input optical signal.

[0076] The number of channels in the optical signal determines the number of sampling points and the minimum resolution across the wavelength range. When the number of channels is small, a correspondingly smaller number of sampling points can be set. Consequently, a smaller number of underdetermined equations are required to reconstruct the optical signal's spectrum. Therefore, by sending different control signals, a corresponding number of output spectra are obtained to construct the corresponding underdetermined equations.

[0077] S200: Spectroscopically reconstructing the input optical signal based on the multiple different output optical signals. When constructing the spectral reconstruction matrix (i.e., the underdetermined system of equations), the response of the spectral perturbation structure to the spectrum (i.e., the response function) is known. The optical powers of the multiple different output optical signals, collected by photodetectors, are also known. Therefore, the optical powers of the output optical signals at each sampling point can be solved.

[0078] S300: Obtaining the spectrum of the input optical signal. Reconstruct the solved optical power of the output optical signal at the sampling point in the frequency domain to obtain the spectrum of the input optical signal.

[0079] However, it should be noted that for the spectrum modulation chip, only a purely spatial spectrum perturbation structure is used. In step S100, there is no need to send a control signal to the spectrum modulation chip, and multiple different output optical signals corresponding to the input optical signal can be directly obtained.

[0080] like Figure 9 As shown, the optical channel monitor and the optical channel monitoring method are used to monitor an optical signal having more than fifty channels, and finally the spectrum of the output optical signal after computational reconstruction is obtained. As can be seen from the figure, the channels in the reconstructed spectrum almost overlap with the signals in the original spectrum.

[0081] The above are only specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modifications that do not deviate from the functional and structural principles of the present invention are intended to be included within the scope of the claims.

Claims

1. An optical channel monitor, comprising a photodetector and a signal processor, characterized in that: The system further includes a spectral modulation chip; the spectral modulation chip includes an optical input port, an optical output port group, and a spectral perturbation structure, the optical output port group including at least one optical output port, the spectral perturbation structure receiving an optical signal input through the optical input port, the spectral perturbation structure including a plurality of passive spectral perturbation units with different spectral response functions or spectral perturbation units with time-domain adjustable spectral response functions arranged in parallel in space, for performing multiple perturbation processes on the input optical signal; wherein the spectral perturbation unit with time-domain adjustable spectral response function includes a plurality of cascaded active tunable spectral perturbation units, the perturbation process changes the optical characteristics of the input optical signal according to a preset spectral response function, thereby changing the power distribution of the output optical signal in frequency; the bandwidth of the spectral perturbation structure is greater than or equal to the entire bandwidth of the optical signal; multiple output optical signals with different optical characteristics obtained after multiple perturbation processes are output through the optical output port group; the photodetector is used to convert the optical power of the output optical signal into a corresponding electrical signal; and the signal processor is used to obtain data related to the spectrum of the input optical signal based on the multiple output optical signals.

2. The optical channel monitor according to claim 1, wherein: The spectral perturbation structure includes multiple cascaded active tunable spectral perturbation units, and the signal processor is further used to generate a control signal; the optical output port group includes one optical output port; the multiple cascaded active tunable spectral perturbation units generate different disturbances in time sequence according to the tuning of the control signal, so that the optical output port outputs multiple different output optical signals at different times.

3. The optical channel monitor according to claim 1, wherein: The spectral perturbation structure includes multiple optical path components, which are connected to the optical input port through an optical splitter. Each of the optical path components includes multiple cascaded passive spectral perturbation units. The multiple passive spectral perturbation units in different optical path components have different spectral responses, so that the multiple optical path components produce different spectral perturbations on the input optical signal; the optical output port group includes multiple optical output ports, and the multiple optical output ports correspond one-to-one to the multiple optical path components to output multiple different output optical signals; the different output optical signals have different power distributions in the frequency domain.

4. The optical channel monitor according to claim 1, wherein: The spectral perturbation structure includes a plurality of optical path components, wherein the plurality of optical path components are connected to the optical input port via an optical splitter; the optical path components include a plurality of cascaded spectral perturbation units, wherein the plurality of spectral perturbation units in different optical path components have different spectral responses, so that the plurality of optical path components generate different spectral perturbations on the input optical signal, wherein the plurality of cascaded spectral perturbation units of at least one optical path component are a plurality of cascaded actively tunable spectral perturbation units; The signal processor is further used to provide a control signal for tuning the active tunable spectrum perturbation unit; the optical output port group includes multiple optical output ports, and the multiple optical output ports correspond one-to-one to the multiple optical path components to output different output optical signals.

5. The optical channel monitor according to claim 2 or 4, characterized in that: At least one of the active tunable spectral perturbation units in the spectral perturbation structure is an active asymmetric Mach-Zehnder interferometer, which has two tuning arms of unequal lengths and a phase modulator arranged on at least one of the tuning arms. The phase modulator tunes the phase of the optical signal entering the tuning arm according to the control signal to adjust the power distribution of the output optical signal in the frequency domain.

6. The optical channel monitor according to claim 5, characterized in that: There is an arm length difference between the two tuning arms of the active asymmetric Mach-Zehnder interferometer; and a plurality of active asymmetric Mach-Zehnder interferometers have different arm length differences.

7. The optical channel monitor according to claim 2 or 4, characterized in that: At least one of the active tunable spectral perturbation units in the spectral perturbation structure is a microring filter with a resonant structure. A phase modulator is provided in the resonant structure of the microring filter. The phase modulator tunes the phase of the optical signal entering the resonant structure according to the control signal to adjust the power distribution of the output optical signal in the frequency domain.

8. The optical channel monitor according to claim 7, wherein: The microrings of the plurality of microring filters have different circumferences.

9. The optical channel monitor according to claim 3 or 4, characterized in that: At least one of the passive spectrum perturbation unit or spectrum perturbation units in the spectrum perturbation structure is a passive asymmetric Mach-Zehnder interferometer or a micro-ring filter with a resonant structure.

10. An optical channel monitoring method, applied to the optical channel monitor according to claim 1, characterized in that: include: obtaining a plurality of different output optical signals corresponding to the input optical signal; Obtaining the optical power of the output optical signal at each sampling point based on a known spectral response function of the spectral perturbation structure and the optical powers of a plurality of different output optical signals, so as to perform spectral computation and reconstruction on the input optical signal; wherein the optical power of the output optical signal is acquired by a photodetector; The optical power of the output optical signal at the sampling point is reconstructed in the frequency domain to obtain the spectrum of the input optical signal.

11. The optical channel monitoring method according to claim 10, wherein: Before the step of obtaining a plurality of different output optical signals corresponding to the input optical signal, the method further includes sending a control signal to the spectrum modulation chip; wherein the number of the plurality of different output optical signals is related to the control signal.

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