An optical channel monitor and monitoring method

Abstract

The invention 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 photoelectric detector, a signal processor and a spectrum modulation device; the spectrum modulation device comprises an optical input port, a spectrum perturbation structure, a polarization beam splitter and a plurality of optical output ports; the spectrum perturbation structure is used for receiving and performing perturbation processing on an input optical signal to obtain a plurality of output optical signals with different optical characteristics, and transmit the signals to the polarization beam splitter; the polarization beam splitter is used for beam splitting the output optical signal to obtain a plurality of polarized lights with different polarization states, and output the plurality of polarized lights through a plurality of optical output ports respectively; a plurality of photoelectric detectors are provided and are respectively used for converting the optical power of the corresponding polarized lights into corresponding electrical signals; the signal processor is used for obtaining relevant data of the spectra of the plurality of polarized lights in the input optical signal according to the plurality of polarized lights in the plurality of output optical signals; the influence of the polarized light in the optical channel on the monitoring effect can be avoided.

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] Common optical channel monitors are mainly divided into spectroscopic type and tunable filter type. The filter resolution of these two types of optical channel monitors is not enough, the modulation rate is slow, and the spectrum scanning rate is slow, so real-time monitoring of signals cannot be achieved.

[0003] To this end, the inventors have designed a spectral modulation device for an optical channel monitor based on the principle of a computational reconstruction spectrometer. However, this spectral modulation device for optical channel monitoring can only respond to a single polarized light signal. In actual applications, the (light) signal received at the monitoring end is an optical signal that has been transmitted through a very long section of optical fiber. The polarization state of the optical signal will change during transmission in the optical fiber. Even if the transmitting end is a standard TE polarization mode, it may be other linear polarization modes or elliptical polarization modes at the receiving end, thereby affecting the monitoring effect of the optical signal in the optical channel. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art to a certain extent. To this end, the present invention provides an optical channel monitor and a monitoring method, which can reduce the adverse effects of polarization on monitoring effects.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions in the first aspect:

[0006] An optical channel monitor includes a photodetector and a signal processor, and also includes a spectrum modulation device;

[0007] The spectrum modulation device comprises a light input port, a spectrum perturbation structure, a polarization beam splitter and a plurality of light output ports;

[0008] The spectrum perturbation structure is used to receive an input optical signal input through the optical input port, and perform perturbation processing on the input optical signal to obtain a plurality of output optical signals with different optical characteristics, and transmit them to the polarization beam splitter;

[0009] The polarization beam splitter is used to split the output optical signal to obtain a plurality of polarized lights with different polarization states, and output the plurality of polarized lights through the plurality of optical output ports respectively;

[0010] The photoelectric detectors are provided in plurality and are respectively used to convert the optical power of the corresponding polarized light into corresponding electrical signals; the signal processor is used to obtain relevant data of the spectra of the multiple polarized lights in the input optical signal according to the multiple polarized lights in the multiple output optical signals.

[0011] Optionally, the spectral modulation device includes two optical output ports; the polarization beam splitter is used to split the output optical signal to obtain two orthogonal polarized lights, and output the two polarized lights through the two optical output ports respectively; and two photodetectors are also provided corresponding to the optical output ports.

[0012] Optionally, the spectral perturbation structure includes a plurality of cascaded active tunable spectral perturbation units, and the signal processor is also used to generate a control signal; the plurality of cascaded active tunable spectral perturbation units generate different disturbances in timing according to the tuning of the control signal, so that the plurality of optical output ports respectively output a plurality of groups of multiple polarized lights corresponding to a plurality of different output optical signals at different times.

[0013] Optionally, the active tunable optical spectrum perturbation unit includes a first coupler for receiving an input optical signal and a second coupler for outputting an optical signal; the first coupler and the second coupler are both capable of coupling multiple polarized lights in the input optical signal.

[0014] Optionally, the first coupler and the second coupler between two adjacent cascade structures in the spectrum perturbation structure multiplex the same duplex coupler.

[0015] Optionally, the duplex coupler includes two parallel waveguides; there is a gradually varying spacing between the two waveguides so as to simultaneously respond to multiple polarized lights in the input optical signal.

[0016] 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 multiple polarized lights corresponding to the output optical signal in the frequency domain.

[0017] 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 light in two polarization states with the output optical signal in the frequency domain.

[0018] In addition, the present invention further provides an optical channel monitoring method in a second aspect, comprising:

[0019] Acquire multiple groups of data related to multiple polarized lights corresponding to multiple different output optical signals; the multiple different output optical signals correspond to the same input optical signal;

[0020] Performing spectrum calculation and reconstruction on the input optical signal according to the multiple groups of correlation data of the multiple polarized lights;

[0021] Obtain the spectrum of the input optical signal.

[0022] Optionally, before the step of obtaining multiple groups of related data of multiple polarized lights corresponding to multiple different output light signals, it also includes sending a control signal to the spectral modulation device; wherein the multiple groups of related data of multiple polarized lights corresponding to multiple different output light signals are related to the control signal.

[0023] This solution solves the polarization sensitivity problem in the optical channel monitor. Regardless of the polarization state of the input light, the optical channel monitor of this solution can effectively reconstruct the spectral information.

[0024] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. The best embodiments or means of the present invention will be described in detail in conjunction with the drawings, but they are not intended to limit the technical solutions of the present invention. In addition, there are multiple features, elements, and components that appear in each of the following texts and drawings, and different symbols or numbers are marked for convenience, but they all represent components with the same or similar structures or functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the accompanying drawings:

[0026] Figure 1 4 is a principle block diagram of the optical channel monitor described in this embodiment.

[0027] Figure 2 Schematic diagram of the structure of the spectrum modulation device described in this embodiment.

[0028] Figure 3 Schematic diagram of the structure of the spectrum perturbation structure in this embodiment, showing a time-domain adjustable spectrum perturbation structure.

[0029] Figure 4 Schematic diagram of the structure of the active tunable spectrum perturbation unit in this embodiment, showing the active asymmetric Mach-Zehnder interferometer therein.

[0030] Figure 5 Schematic diagram of the structure of the coupler described in this embodiment.

[0031] Figure 6a and Figure 6bThey are response curve diagrams of the duplex coupler described in this embodiment in two polarization states.

[0032] Figure 7 Schematic diagram of the structure of the polarization beam splitter described in this embodiment.

[0033] Figure 8 Schematic diagram of the structure of the polarization separation rotator described in this embodiment.

[0034] Fig. 9 Flow chart of the optical channel monitoring method described in this embodiment.

[0035] Fig.10 It is a response curve diagram of two polarization states in a certain channel (phase modulator modulation is consistent) using the optical channel monitoring method in this embodiment.

[0036] Fig.11a and Fig.11b Schematic diagram of the reconstruction results of two polarized lights.

[0037] Among them, 100 is an active tunable spectral perturbation unit; 200 is a polarization beam splitter; and 300 is a photodetector. DETAILED DESCRIPTION

[0038] Embodiments of the present invention are described in detail below, 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 with the same or similar functions. The embodiments in the implementation manner are intended to be used to explain the present invention and should not be construed as limiting the present invention.

[0039] References in this specification to "one embodiment" or "an example" or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment itself may be included in at least one embodiment of the present patent disclosure. The appearance of the phrase "in one embodiment" in various places in the specification does not necessarily refer to the same embodiment.

[0040] In order to solve the problem of polarization phenomenon in optical channel monitoring based on the principle of computational reconstruction spectrometer, which has an adverse effect on the monitoring effect, the inventors added a polarization separation device at the receiving end, that is, in the optical channel monitor, to decompose the received light into two orthogonal linear polarized lights (TE and TM), and then used two spectral modulation devices to process the two polarized lights separately. This processing method will not only increase the size and production cost of the equipment, but also increase the overall power consumption and use cost of the equipment.

[0041] To this end, the inventors have made further improvements and proposed an optical channel monitor and monitoring method, in which the polarization separation device is placed after the filter (i.e., the spectral perturbation structure), and the optical signal is first disturbed by passing through the filter. In the process of the optical signal passing through the filter, the filter can simultaneously respond to the optical components of the optical signal in two different polarizations, so that the same filter can be used to complete the perturbation processing of the two polarization components of the same optical signal, so that the relevant data of the two polarization lights of the output optical signal corresponding to the same input optical signal can be obtained respectively, so as to construct a spectral reconstruction matrix, and then restore the input optical signal after solving the polarization lights of the input optical signal respectively.

[0042] like Figure 1 and Figure 2 As shown, an optical channel monitor is shown, which is used to monitor the optical signal in the optical channel of the optical transmission network system. The optical transmission network can be a dense wavelength division multiplexing (DWDM) optical transmission network or a sparse wavelength division multiplexing (CWDM) optical transmission network, without limitation. The optical channel monitor includes an optical waveguide, a spectrum modulation device, a signal processor and a plurality of photodetectors.

[0043] The optical channel of the optical transmission network system is used to transmit multiplexed signals. A splitter is provided on the optical channel, and the splitter is used to split an optical signal from the multiplexed signal for monitoring. One end of the optical waveguide is connected to the output end of the splitter, and the other end is connected to the optical channel monitor to introduce the optical signal split from the multiplexed signal.

[0044] The spectrum modulation device includes a light input port, a spectrum perturbation structure, a polarization beam splitter and a plurality of light output ports.

[0045] The optical input port is used to receive the optical signal of the optical channel through the optical waveguide. When the optical signal enters the spectrum modulation device through the optical input port, the polarization of the optical signal will no longer change.

[0046] The spectrum perturbation structure is used to receive an input optical signal input through the optical input port, and perform perturbation processing on the input optical signal to obtain a plurality of output optical signals with different optical characteristics, and transmit the signals to the polarization beam splitter.

[0047] The polarization beam splitter can decompose the input optical signal to obtain a plurality of polarized lights with different polarization states, and output the plurality of polarized lights through the plurality of optical output ports, respectively. The optical output ports correspond to the polarized lights one by one.

[0048] The photoelectric detectors are provided in plurality and are respectively used to convert the optical power of the corresponding polarized light into corresponding electrical signals; the signal processor is used to obtain relevant data of the spectra of the multiple polarized lights in the input optical signal according to the multiple polarized lights in the multiple output optical signals.

[0049] The perturbation processing here refers to the fact that some of the optical characteristics of the input optical signal are changed according to the preset spectral response function after passing through the spectral perturbation structure during the transmission process, thereby changing the power distribution of the output optical signal in the frequency domain. The spectral perturbation structure can make different output optical signals have different power distributions in the frequency domain by setting a spectral perturbation unit with an adjustable spectral response function in the time domain (this type of spectral perturbation structure is referred to as a time-domain adjustable spectral perturbation structure), that is, each output optical signal (polarization component, i.e., multiple polarized lights) is unique. The spectral response function can be achieved by designing different parameters of the spectral perturbation structure.

[0050] The disturbance processing can be performed once or multiple times. When multiple disturbances are performed, parameters are set so that each disturbance produces a different output. With the superposition of the number of disturbances (including the order of disturbances under different parameter settings), the power distribution of each output optical signal in the frequency domain has high-intensity randomness, and multiple output optical signals are highly uncorrelated. At the same time, in order to enable the spectral disturbance structure to change the power distribution of the output optical signal in its entire frequency domain (bandwidth), the bandwidth of the spectral disturbance structure is greater than or equal to the entire bandwidth of the optical signal.

[0051] It should be noted that the conventional spectrum calculation and reconstruction method uses the relevant data of the spectra of multiple different output optical signals (ie, the power distribution of the spectra in the frequency domain) to construct a spectrum reconstruction matrix.

[0052] Different from the principle of conventional computational reconstruction spectrometers, the signal processor in this solution does not obtain data related to the spectra of (multiple different) output optical signals, but data related to the spectra of multiple polarized lights (corresponding to the output optical signals). Multiple polarized lights are polarization components of the output optical signal. In this solution, two orthogonal linear polarized lights (TE and TM) are used as an example for explanation. It can also be elliptical polarization components, etc.

[0053] In this way, the spectrum reconstruction matrix of the polarized light (of the output optical signal) can be constructed separately, so as to solve the polarized light of the input optical signal. The polarized light of the input optical signal is the polarization component of the input optical signal. Once the polarization components of all the input optical signals are known, the input optical signal can be restored, thereby avoiding the influence of the polarization phenomenon on the monitoring effect.

[0054] Therefore, the number of optical output ports, the number of photodetectors, and the number of polarized lights decomposed by the polarization beam splitter are consistent. In addition, the spectrum perturbation structure must respond to the polarization component of the optical signal at the same time when perturbing the input optical signal.

[0055] like Figure 3As shown, the spectrum perturbation structure is time-domain adjustable, including three or more cascaded active tunable spectrum perturbation units 100, hereinafter referred to as multiple cascaded active tunable spectrum perturbation units. Multiple cascaded active tunable spectrum perturbation units are arranged on the optical transmission path between the tube input port and the polarization beam splitter 200.

[0056] The multiple cascaded active tunable spectral perturbation units generate different perturbations in timing according to the tuning of the control signal, so as to transmit multiple different output optical signals to the polarization beam splitter at different times. The polarization beam splitter can decompose the output optical signal into corresponding TE polarized light and TM polarized light, which correspond to each other and exist simultaneously. Since the multiple different output optical signals are generated at different times, the multiple TE polarized lights and TM polarized lights output by the polarization beam splitter are also generated at different times.

[0057] Specifically, Figure 3 and Figure 4 As shown, the active tunable spectrum perturbation unit is an active asymmetric Mach-Zehnder interferometer, which has two tuning arms of unequal lengths and a phase modulator (or phase shifter) disposed on at least one of the tuning arms. The asymmetric Mach-Zehnder interferometer forms an asymmetric structure through two tuning arms of unequal arm lengths. The phase modulator actively 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.

[0058] Preferably, the phase modulator has at least three different phase adjustment states, so that three Mach-Zehnder interferometers can make the output of the spectrum perturbation structure 27 different output light signals, that is, 27 groups of multiple polarized light signals are received by the photodetector 300 .

[0059] It should be noted 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. For example, the arm length difference between the two interference arms in the three-stage asymmetric Mach-Zehnder interferometer can be set to 300um, 500um and 800um respectively to improve the random perturbation effect.

[0060] 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 um; for CWDM (coarse wavelength division multiplexing) channel monitoring applications, the arm length difference of the asymmetric Mach-Zehnder interferometer is between 100 and 1000 um. Those skilled in the art can flexibly set it according to actual conditions without limitation.

[0061] More specifically, the active asymmetric Mach-Zehnder interferometer further includes a first coupler disposed at the input side of the tuning arm and a second coupler disposed at the output side of the tuning arm. The first coupler is used to split the input optical signal into two paths according to a preset splitting ratio and input them into the two tuning arms respectively, and the second coupler is used to combine the output lights of the two tuning arms (also the interference arms) to generate optical interference (i.e., form disturbance).

[0062] In two adjacent asymmetric Mach-Zehnder interferometers, the output light of the second coupler in the previous stage is completely used as the input light of the first coupler in the next stage.

[0063] It should be noted that in two adjacent asymmetric Mach-Zehnder interferometers, the second coupler in the first asymmetric Mach-Zehnder interferometer and the first coupler in the second asymmetric Mach-Zehnder interferometer can reuse the same coupler.

[0064] It should be noted that the first coupler and the second coupler can both couple multiple polarized lights in the input optical signal. In other words, the first coupler and the second coupler can simultaneously respond to all polarization components (i.e., multiple polarized lights) of the output optical signal. The following takes the TE polarized light and TM polarized light of the output optical signal as an example.

[0065] like Figure 5 As shown, a 2*2 coupler (TE / TM duplex) is shown, which has a coupling rate of about 50%, hereinafter referred to as a duplex coupler, and the duplex coupler includes two parallel waveguides. There is a gradual interval between the two waveguides, and there is a minimum interval in the middle, which is not zero distance. From the middle to the two sides, the interval between the two waveguides gradually increases smoothly, and finally the interval remains unchanged, and the two ends of the two waveguides are parallel. The gradual interval enables the duplex coupler to respond to multiple polarized lights in the input optical signal.

[0066] For example, when the input optical signal is connected to port 1 of the duplex coupler, about 50% of the TE polarized light in the input optical signal can be coupled into another waveguide when passing through the gradient structure in the middle, that is, 50% of the TE polarized light is output from port 2, and 50% of the TE polarized light is output from port 3. Similarly, when the input optical signal is connected to port 1 of the duplex coupler, about 50% of the TM polarized light in the input optical signal can be coupled into another waveguide when passing through the gradient structure in the middle, that is, 50% of the TM polarized light is output from port 2, and 50% of the TM polarized light is output from port 3.

[0067] Similarly, when the input optical signal is connected from port 4 of the duplex coupler, part of the TE polarized light and TM polarized light will be coupled into the opposite waveguide and finally output from port 2 and port 3 respectively.

[0068] like Figure 6a and Figure 6b As shown, the response curve of the duplex coupler in two polarization states is shown. It can be seen from the figure that the coupler has basically no loss in different polarization states and the coupling efficiency is around 50%. In actual use, we may also adjust the coupling efficiency of the two to deviate from 50% according to needs.

[0069] It should be noted that a polarization beam splitter (PBS) is a device that separates different input polarization states. Figure 7 , the light containing both TE and TM polarization states is input from the left input port, and after passing through the device, it will be divided into TE and TM and output from two different ports.

[0070] In addition, the polarization splitting rotator (PBRS) is also a polarization beam splitter. Figure 8 It can be seen that the difference is that it converts the input TM wave into TE wave and outputs it from another port. This device can also work in this optical channel monitor. Other similar devices that can separate two polarization states are included in PBS. Some are realized through the chip structure, and some can also be realized through the spatial optical structure, without limitation.

[0071] In addition, as an alternative, the active tunable spectrum perturbation unit can also be a micro-ring filter with a resonant structure, wherein a phase modulator is provided in the resonant structure of the micro-ring filter, and 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 micro-rings of the plurality of micro-ring filters have different circumferences.

[0072] It should be noted that for DWDM (dense wavelength division multiplexing) channel monitoring applications, the ring length of the micro-ring resonant cavity (resonant structure) is between 150 and 2000 um; for CWDM (coarse wavelength division multiplexing) channel monitoring applications, the ring length of the micro-ring resonant cavity is between 100 and 1000 um. Those skilled in the art can flexibly set it according to actual conditions without limitation.

[0073] The photodetector can be an InGaAs detector or a germanium detector. For the germanium detector, it can be integrated with the spectrum modulation device on the same single chip without any restriction.

[0074] In one embodiment, the signal processor further includes a control end, which is electrically connected to the spectrum perturbation structure and is used to control the phase modulators to perform different phase adjustments according to a preset control signal, so that the output ports output different output optical signals.

[0075] It should be noted that the input end of the signal processor is used to process the output signal of the light detector (with a signal amplification circuit, an analog-to-digital conversion circuit, etc.). The signal processor can integrate computing functions and can be used to reconstruct and restore the spectrum of the optical signal without limitation. Similarly, the signal processor can be integrated with the photodetector and the spectrum modulation device on the same single chip.

[0076] For phase modulation by thermal tuning or electrical tuning, an electrical drive module needs to be provided between the signal processor control end and the phase modulator.

[0077] It should be noted that the spectral modulation device adopts a planar optical waveguide device, and the waveguide materials of the device include silicon nitride waveguide, silicon waveguide, silicon oxide waveguide, thin film lithium niobate waveguide, polymer waveguide, etc. These materials can be used to produce a spectral perturbation structure based on a Mach-Zehnder interferometer and a spectral perturbation structure based on a microring filter on the device.

[0078] 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 a prior art and will not be described in detail here.

[0079] At the same time, Fig. 9 As shown, the present embodiment also provides an optical channel monitoring method in the second aspect, including but not limited to the following steps.

[0080] S100: Sending a control signal to a spectrum modulation device to obtain multiple groups of data related to multiple polarized lights corresponding to multiple different output light signals; the multiple different output light signals correspond to the same input light signal.

[0081] The number of channels in the optical signal determines the number of sampling points and the minimum resolution in the wavelength range. When the number of channels in the optical signal is small, a smaller number of sampling points can be set accordingly, and the number of underdetermined equations required to reconstruct the spectrum of the optical signal is also small. Therefore, by sending different control signals to obtain the corresponding number of output spectra, that is, multiple sets of polarized light related data, to construct the corresponding underdetermined equations.

[0082] S200: Spectral calculation and reconstruction of the input optical signal (multiple polarized lights) is performed according to the relevant data of the multiple groups of multiple polarized lights. When constructing the spectrum reconstruction matrix (i.e., the underdetermined equation group), the response of the spectrum perturbation structure to the spectrum (i.e., the response function) is known, and the optical power of the multiple groups of multiple polarized lights is collected by the photoelectric detector and is also known, so the optical power of the multiple polarized lights of the input optical signal at each sampling point can be solved.

[0083] S300: Obtain the spectrum of the input optical signal. Reconstruct the solved optical powers of the multiple polarized lights of the input optical signal at the sampling points according to the frequency domain to obtain the spectrum of the multiple polarized lights of the input optical signal, and finally restore the spectrum of the input optical signal using the spectrum of the multiple polarized lights of the input optical signal.

[0084] like Fig.10 As shown in the figure, the response curves of the two polarization states of a certain channel (the phase modulator modulation is consistent) are shown. The response curves of the two polarization states are not exactly the same. They will have different transmission matrices, denoted as T TE and T TM .

[0085] By detecting the photoelectric values ​​under different channels, the corresponding transmission equation is obtained

[0086] T TE x = y TE

[0087] T TM x = y TM

[0088] Among them, y TE and TM It is obtained by using the known standard spectrum through the above optical channel monitor and is a known quantity. Therefore, the spectrum x is solved by using an algorithm.

[0089] This scheme can selectively use a polarization component with greater intensity when the TE and TM components are extremely unbalanced, and can effectively reconstruct the detection spectrum.

[0090] like Fig.11a and Fig.11b , are the results of reconstruction of two polarized lights, where TE-refernce is the actual spectrum of TE polarized light, TE-recon is the reconstructed spectrum of TE polarized light, TM-refernce is the actual spectrum of TM polarized light, and TM-recon is the reconstructed spectrum of TM polarized light. It can be seen that both polarizations can effectively reconstruct the spectral information.

[0091] Compared with traditional solutions, only one polarization component can be used, usually TE. When the TE component is small, the signal-to-noise ratio will be reduced, and sometimes even effective spectral information cannot be reconstructed.

[0092] On the other hand, when the strengths of TE and TM are relatively balanced, the actual TE and TM equations can be combined

[0093]

[0094] This actually expands the number of channels of the spectrometer, that is, the number of equations in the linear equation system is expanded, which can further improve the accuracy of the reconstructed spectrum.

[0095] The above are only specific embodiments of the present invention, but the protection scope 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 modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. An optical channel monitor, comprising a photodetector and a signal processor, characterized in that: Also included is a spectrum modulation device; The spectrum modulation device comprises a light input port, a spectrum perturbation structure, a polarization beam splitter and a plurality of light output ports; The spectrum perturbation structure is used to receive an input optical signal input through the optical input port, and perform perturbation processing on the same input optical signal to obtain a plurality of output optical signals with different optical characteristics, and transmit them to the polarization beam splitter; The polarization beam splitter is used to split the output optical signal to obtain a plurality of polarized lights with different polarization states, and output the plurality of polarized lights through the plurality of optical output ports respectively; The photodetector is provided with a plurality of photodetectors and is respectively used to convert the optical powers of the plurality of polarized lights corresponding to the same input optical signal into corresponding electrical signals; the signal processor is used to obtain data related to the spectra of the plurality of polarized lights in the input optical signal according to the plurality of polarized lights in the plurality of output optical signals; The spectrum perturbation structure includes a plurality of cascaded active tunable spectrum perturbation units, and the signal processor is further used to generate a control signal; the plurality of cascaded active tunable spectrum perturbation units generate different perturbations in timing according to the tuning of the control signal, so that the plurality of optical output ports respectively output a plurality of groups of a plurality of polarized lights corresponding to a plurality of different output optical signals at different times; The active tunable optical spectrum perturbation unit comprises a first coupler for receiving an input optical signal and a second coupler for outputting an optical signal; the first coupler and the second coupler are both capable of coupling multiple polarized lights in the input optical signal; The first coupler and the second coupler between two adjacent cascade structures in the spectrum perturbation structure multiplex the same duplex coupler; The duplex coupler includes two parallel waveguides, with a gradual spacing between the two waveguides, a minimum spacing in the middle, which is not zero distance, and the spacing between the two waveguides gradually increases from the middle to both sides, and finally the spacing remains unchanged, and the two ends of the two waveguides are parallel to simultaneously respond to multiple polarized lights in the input optical signal.

2. The optical channel monitor according to claim 1, characterized in that: The spectral modulation device includes two optical output ports; the polarization beam splitter is used to split the output optical signal to obtain two orthogonal polarized lights, and output the two polarized lights through the two optical output ports respectively; and two photodetectors are also provided corresponding to the optical output ports.

3. The optical channel monitor according to claim 1, 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, and 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 multiple polarized lights corresponding to the output optical signal in the frequency domain.

4. The optical channel monitor according to claim 3, 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 two polarization states of light corresponding to the output optical signal in the frequency domain.

5. An optical channel monitoring method, characterized in that: The optical channel monitoring method is applied to the optical channel monitor according to any one of claims 1 to 4, and the method comprises: Acquire multiple groups of data related to multiple polarized lights corresponding to multiple different output optical signals; the multiple different output optical signals correspond to the same input optical signal; Performing spectrum calculation and reconstruction on the input optical signal according to the multiple groups of correlation data of the multiple polarized lights; Obtain the spectrum of the input optical signal.

6. The optical channel monitoring method according to claim 5, characterized in that: Before the step of acquiring multiple groups of related data of multiple polarized lights corresponding to multiple different output light signals, it also includes sending a control signal to the spectral modulation device; wherein the multiple groups of related data of multiple polarized lights corresponding to multiple different output light signals are related to the control signal.

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