CN114079505B

CN114079505B - Optical signal power detection circuit, system, method and chip

Info

Publication number: CN114079505B
Application number: CN202010839817.3A
Authority: CN
Inventors: 潘超; 邓宁; 赵壮
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-08-19
Filing date: 2020-08-19
Publication date: 2023-07-18
Anticipated expiration: 2040-08-19
Also published as: CN114079505A; WO2022037154A1

Abstract

The application provides a power detection circuit, a system, a method and a chip of an optical signal, and belongs to the technical field of optical communication. The mixed optical signal received by the power detection circuit of the optical signal is obtained by coherently mixing the detected optical signal and the local oscillation optical signal. Because the local oscillator optical signal comprises N optical carriers, and the central frequencies of at least two optical carriers in the N optical carriers are different, the parallel detection of the power at least two different frequency points in the detected optical signal can be realized based on the mixed optical signal, so that the efficiency of power detection is effectively improved.

Description

Optical signal power detection circuit, system, method and chip

Technical Field

The present disclosure relates to the field of optical communications technologies, and in particular, to a power detection circuit, a system, a method, and a chip for optical signals.

Background

In order to monitor the performance of an optical communication system to ensure the reliability of the optical communication system, it is necessary to detect the power of an optical signal transmitted in the optical communication system.

In the related art, a power detection system for an optical signal generally includes a tunable laser, a coherent receiver, a low-pass filter, and an operator. The coherent receiver is used for coherently mixing the optical signals to be detected and the optical signals emitted by the tunable laser, and outputting the mixed optical signals to the low-pass filter. The low-pass filter filters the mixed optical signal and outputs the filtered mixed optical signal to the operator. The low-pass filter may output, to the arithmetic unit, a frequency component of the optical signal to be detected, which is identical to a center frequency of the optical signal output by the tunable laser. The arithmetic unit can further calculate and obtain the power of the frequency component which is consistent with the center frequency of the optical signal output by the tunable laser in the optical signal to be detected.

However, when the spectrum width of the optical signal to be detected is wider, the method needs to adjust the wavelength of the optical signal emitted by the tunable laser multiple times to realize the power detection of each frequency point in the optical signal to be detected. The efficiency of the power detection method is low.

Disclosure of Invention

The application provides a power detection circuit, a system, a method and a chip for optical signals, which can solve the technical problem of low efficiency of a power detection method in the related technology.

In one aspect, a power detection circuit for an optical signal is provided, where the power detection circuit is configured to receive a mixed optical signal, where the mixed optical signal is obtained by coherently mixing a measured optical signal and a local oscillator optical signal, where the local oscillator optical signal includes N optical carriers, and center frequencies of at least two optical carriers in the N optical carriers are different, and N is an integer greater than 1; the power detection circuit is also used for filtering the mixed optical signal and determining the power of the detected optical signal at the center frequency of each optical carrier according to the filtered mixed optical signal. The center frequency of each optical carrier may be located in the spectrum range of the measured optical signal.

Because the local oscillator optical signals coherently mixed in the mixed optical signals comprise at least two optical carriers with different center frequencies, the parallel detection of the power at least two different frequency points in the detected optical signals can be realized based on the mixed optical signals, and therefore the efficiency of power detection is effectively improved.

Optionally, the power detection circuit may further be configured to: the center frequency of each optical carrier wave in the local oscillation optical signal emitted by the comb-shaped optical source is adjusted, so that the center frequency of each optical carrier wave is changed in a corresponding frequency spectrum range, and the frequency spectrum ranges corresponding to the center frequencies of different optical carrier waves are different.

Because the center frequency of each optical carrier can be changed in a corresponding frequency spectrum range, the number of frequency points detected when the power detection is carried out on the detected optical signals can be effectively increased on the premise of not increasing the number N of the optical carriers. Furthermore, the spectrum shape of the detected optical signal can be accurately detected, and the accuracy of power detection is improved.

Optionally, the measured optical signal may be a wavelength division multiplexing signal, where the wavelength division multiplexing signal includes N service optical signals, and the spectrum widths of the service optical signals are the same and the wavelengths are different from each other; each service optical signal is a signal obtained by modulating the top, and the modulation frequencies of different service optical signals are different; the power detection circuit can be used for adjusting the center frequency of each optical carrier according to the target frequency interval, so that the center frequency of each optical carrier is changed in the frequency spectrum range of a service optical signal; wherein the target frequency interval is smaller than the spectral width of the traffic light signal.

Because the frequency spectrum widths of the business optical signals with different wavelengths are the same, the power detection circuit can adjust the center frequency of each optical carrier according to the fixed target frequency interval, thereby effectively simplifying the frequency adjustment operation.

Optionally, the measured optical signal may be a wavelength division multiplexing signal, where the wavelength division multiplexing signal includes a plurality of service optical signals, wavelengths of the plurality of service optical signals are different from each other, and spectrum widths of at least two service optical signals in the plurality of service optical signals are different, each service optical signal includes at least one slice signal, each slice signal is a signal obtained by modulating a top, modulation frequencies of different slice signals are different, and spectrum widths of different slice signals are the same, and N is a total number of slice signals included in the wavelength division multiplexing signal; the power detection circuit can be used for adjusting the center frequency of each optical carrier according to the target frequency interval, so that the center frequency of each optical carrier is changed in the frequency spectrum range of one slice signal; wherein the target frequency interval is smaller than the spectral width of the slice signal.

In a scene where the spectral widths of the service optical signals are not identical, the service optical signals can be sliced to obtain a plurality of sliced signals with identical spectral widths. Because the frequency spectrum widths of the slicing signals are the same, the central frequencies of the N optical carriers can be uniformly adjusted according to the same target frequency interval, and therefore the frequency adjustment operation is effectively simplified.

Optionally, each optical carrier is a signal obtained by modulating the top, and the modulation frequencies of different optical carriers are different; the power detection circuit may be configured to adjust the center frequency of each optical carrier at a target frequency interval that is less than the frequency difference of the center frequencies of adjacent two optical carriers.

The scheme provided by the application can also adjust the top of the optical carrier, so that the requirement of the detected optical signal to be detected can be reduced. For example, even if each service optical signal included in the wavelength division multiplexed signal is not modulated or the spectrum widths of each service optical signal are different, effective detection of the power of each service optical signal may be achieved based on the modulated optical carrier.

Optionally, the mixed optical signal comprises four components, the four components being a quadrature component of the first polarization component, an in-phase component of the first polarization component, a quadrature component of the second polarization component, and an in-phase component of the second polarization component, respectively; the power detection circuit may include: a low pass filter, an operator, a comb filter, and a power detection sub-circuit; the low-pass filter is used for respectively carrying out low-pass filtering on the four components; the arithmetic unit is used for determining the power of the four components after low-pass filtering; the comb filter is used for carrying out comb filtering on the power of the four components, wherein the number of pass bands of the comb filter is larger than or equal to N, and the center frequency of each pass band is equal to one modulation frequency; the power detection sub-circuit is used for determining the power of the comb-filtered four components at each modulation frequency to obtain the modulated top power corresponding to each modulation frequency, and determining the power of the tested optical signal at the center frequency of the optical carrier according to the modulated top power corresponding to each modulation frequency, the intensity of the optical carrier corresponding to the modulation frequency and the modulated top depth corresponding to the modulation frequency.

The power of the measured optical signal at the center frequency of the optical carrier is positively correlated with the peak-adjusting power, and is negatively correlated with the intensity of the optical carrier and the peak-adjusting depth. In a scenario where N service optical signals included in a wavelength division multiplexing signal are modulated respectively, an optical carrier corresponding to a modulation frequency refers to: an optical carrier whose center frequency varies within the spectral range of the traffic optical signal modulated with the modulation frequency. In a scenario where N slice signals included in the wavelength division multiplexed signal are modulated, the optical carrier corresponding to the modulation frequency means: an optical carrier whose center frequency varies within the spectral range of the sliced signal modulated with the modulation frequency. In the scenario of performing top modulation on N optical carriers, the optical carrier corresponding to the modulation frequency refers to: the modulated optical carrier is used.

Optionally, an ith modulation frequency in the N modulation frequencies corresponds to an ith optical carrier in the N optical carriers, where i is a positive integer not greater than N;the measured optical signal is at the center frequency f of the ith optical carrier _Ci The power at this point satisfies:

wherein P is _Pi For the peak modulation power corresponding to the ith modulation frequency, A _Ci For the intensity of the ith optical carrier, a _i And (5) the modulation top depth corresponding to the ith modulation frequency.

In another aspect, there is provided a power detection apparatus of an optical signal, the power detection apparatus including: a coherent receiver and a power detection circuit; the coherent receiver is used for carrying out coherent mixing on a detected optical signal and a local oscillator optical signal to obtain a mixed optical signal, and sending the mixed optical signal to the power detection circuit, wherein the local oscillator optical signal comprises N optical carriers, the center frequencies of at least two optical carriers in the N optical carriers are different, and N is an integer greater than 1; the power detection circuit is used for receiving the mixed optical signal, filtering the mixed optical signal and determining the power of the tested optical signal at the center frequency of each optical carrier according to the filtered mixed optical signal.

Alternatively, the coherent receiver and the power detection circuit may be integrally provided. For example, the power detection circuit may be an integrated circuit, which may be provided in the coherent receiver.

Optionally, an ith modulation frequency in the N modulation frequencies corresponds to an ith optical carrier in the N optical carriers, where i is a positive integer not greater than N; the measured optical signal is at the center frequency f of the ith optical carrier _Ci The power at this point satisfies:

In yet another aspect, there is provided a power detection system for an optical signal, the power detection system comprising: a comb light source, a coherent receiver and a power detection circuit; the comb-shaped light source is used for transmitting local oscillation light signals, the local oscillation light signals comprise N light carriers, the center frequencies of at least two light carriers in the N light carriers are different, and N is an integer larger than 1; the coherent receiver is used for carrying out coherent mixing on the detected optical signal and the local oscillator optical signal to obtain a mixed optical signal, and sending the mixed optical signal to the power detection circuit; the power detection circuit is used for filtering the mixed optical signals and determining the power of the detected optical signals at the center frequency of each optical carrier according to the filtered mixed optical signals. The center frequency of each optical carrier may be located in the spectrum range of the measured optical signal.

Alternatively, the comb-like light source may comprise a frequency comb-like light source; or the comb-shaped light source comprises a combiner and a plurality of frequency comb light sources with different wave bands, and the combiner is used for combining the optical carriers emitted by the plurality of frequency comb light sources to obtain the local oscillation optical signals.

For a scene with a narrower band occupied by the detected light signal to be detected, the comb-shaped light source can only comprise one frequency comb-shaped light source, so that the cost and the volume of the comb-shaped light source are reduced. For a scene with a wider wave band occupied by the detected light signal to be detected, the comb-shaped light source can comprise a plurality of frequency comb light sources so as to cover the wave band occupied by the detected light signal, thereby realizing effective detection of the power of the detected light signal.

In yet another aspect, an optical communication system is provided, the system comprising: the power detection system for an optical signal as provided in the above aspect, a first optical transceiver device, a second optical transceiver device, and at least one optical amplifier connected between the first optical transceiver device and the second optical transceiver device;

The coherent receiver in the power detection system is connected with a target device, the target device comprises at least one of the at least one optical amplifier, the first optical transceiver and the second optical transceiver, and the coherent receiver is used for receiving the measured optical signal transmitted by the target device.

Alternatively, the optical communication system may comprise a power detection system for a plurality of optical signals.

In still another aspect, there is provided a power detection method of an optical signal, which can be applied to the power detection circuit provided in the above aspect, the method including: the method comprises the steps of receiving a mixed optical signal obtained by coherently mixing a detected optical signal and a local oscillation optical signal, filtering the mixed optical signal, and determining the power of the detected optical signal at the central frequency of each optical carrier according to the filtered mixed optical signal; the local oscillator optical signal comprises N optical carriers, wherein the central frequencies of at least two optical carriers in the N optical carriers are different, and N is an integer larger than 1.

Optionally, the method may further include: the center frequency of each optical carrier in the local oscillation optical signal is adjusted, so that the center frequency of each optical carrier is changed in one frequency spectrum range, and the center frequencies of different optical carriers are changed in different frequency spectrum ranges.

Optionally, the measured optical signal is a wavelength division multiplexing signal, the wavelength division multiplexing signal includes N service optical signals, the frequency spectrum widths of the N service optical signals are the same, each service optical signal is a signal obtained by modulating the top, and the modulation frequencies of different service optical signals are different; accordingly, the process of adjusting the center frequency of each optical carrier in the local oscillator optical signal may include: according to the target frequency interval, the center frequency of each optical carrier in the local oscillation optical signal is adjusted, so that the center frequency of each optical carrier is changed in the frequency spectrum range of a service optical signal; wherein the target frequency interval is smaller than the spectral width of the traffic light signal.

Optionally, the measured optical signal is a wavelength division multiplexing signal, the wavelength division multiplexing signal includes at least two service optical signals in a plurality of service optical signals, the spectrum widths of the at least two service optical signals are different, each service optical signal includes at least one slice signal, each slice signal is a signal obtained by modulating a top, modulation frequencies of different slice signals are different, the spectrum widths of the different slice signals are the same, and N is the total number of slice signals included in the wavelength division multiplexing signal; accordingly, the process of adjusting the center frequency of each optical carrier in the local oscillator optical signal may include: according to the target frequency interval, the center frequency of each optical carrier is adjusted to enable the center frequency of each optical carrier to change in the frequency spectrum range of one slice signal; wherein the target frequency interval is smaller than the spectral width of the slice signal.

Optionally, each optical carrier is a signal obtained by modulating the top, and the modulation frequencies of different optical carriers are different; the process of adjusting the center frequency of each optical carrier in the local oscillator optical signal may include: the center frequency of each optical carrier is adjusted according to a target frequency interval that is less than the frequency difference of the center frequencies of adjacent two optical carriers.

Optionally, the mixed optical signal comprises four components, the four components being a quadrature component of the first polarization component, an in-phase component of the first polarization component, a quadrature component of the second polarization component, and an in-phase component of the second polarization component, respectively; filtering the mixed optical signal may include: respectively carrying out low-pass filtering on the four components; from the filtered mixed optical signals, determining the power of each traffic optical signal at the center frequency of one optical carrier may include: determining the power of the four low-pass filtered components; comb filtering the power of the four components by a comb filter, wherein the comb filter has a plurality of pass bands, and the center frequency of each pass band is equal to one modulation frequency; determining the power of the comb-filtered power of the four components at each modulation frequency to obtain the top modulation power corresponding to each modulation frequency; and determining the power of the measured optical signal at the center frequency of the optical carrier according to the top modulation power corresponding to each modulation frequency, the intensity of the optical carrier corresponding to the modulation frequency and the top modulation depth corresponding to the modulation frequency.

Optionally, the ith modulation frequency corresponds to the ith optical carrier, i being a positive integer not greater than N; the center frequency f of the measured optical signal at the ith optical carrier _Ci The power at this point satisfies:

wherein P is _Pi For the peak modulation power corresponding to the ith modulation frequency, A _Ci For the intensity of the ith optical carrier, a _i And the modulation depth corresponding to the ith modulation frequency.

The technical effects brought by any design manner of the power detection device, the system and the method for optical signals provided in the above aspect can be referred to the technical effects brought by the corresponding design manner in the power detection circuit for optical signals, and are not repeated here.

In a further aspect, a chip is provided, the chip comprising programmable logic circuits and/or program instructions for implementing the method of power detection of an optical signal as provided in the above aspect when the chip is operating.

In yet another aspect, a power detection circuit is provided, the power detection circuit may include: the system comprises a memory, a processor and a computer program stored in the memory and capable of running on the processor, wherein the processor realizes the power detection method of the optical signal provided by the aspect when executing the computer program.

In yet another aspect, a computer-readable storage medium is provided, in which instructions are stored which, when run on a computer, cause the computer to perform the method of power detection of an optical signal as provided in the above aspect.

In a further aspect, there is provided a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method of power detection of an optical signal as provided in the above aspect.

In summary, the present application provides a power detection circuit, a system, a method, and a chip for optical signals, where a mixed optical signal received by the power detection circuit is obtained by coherently mixing a detected optical signal and a local oscillator optical signal, and the local oscillator optical signal includes N optical carriers, and center frequencies of at least two optical carriers in the N optical carriers are different. Based on the mixed optical signals, parallel detection of the power of the detected optical signals at least two different frequency points can be realized, so that the efficiency of power detection is effectively improved. And the power detection circuit can also adjust the center frequency of each optical carrier in a frequency spectrum range corresponding to each optical carrier, so that the power detection of a plurality of frequency points of the detected optical signal in each frequency spectrum range can be realized, the power detection precision of the detected optical signal can be effectively improved, and the spectrum shape detection of the detected optical signal can be realized.

Drawings

Fig. 1 is a schematic structural diagram of an optical communication system according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of a power detection system for optical signals according to an embodiment of the present application;

fig. 3 is a schematic spectrum diagram of a measured optical signal and a local oscillator optical signal according to an embodiment of the present application;

fig. 4 is a schematic diagram of a slicing signal according to an embodiment of the present application;

fig. 5 is a schematic diagram of slicing and topping a service optical signal according to an embodiment of the present application;

fig. 6 is a schematic diagram of adjusting a center frequency of an optical carrier according to an embodiment of the present application;

FIG. 7 is a schematic diagram of another optical signal power detection system according to an embodiment of the present disclosure;

FIG. 8 is a schematic diagram of a power detection system for an optical signal according to an embodiment of the present disclosure;

fig. 9 is a schematic structural diagram of a power detection system of another optical signal according to an embodiment of the present application;

fig. 10 is a schematic structural diagram of a power detection system of another optical signal according to an embodiment of the present application;

fig. 11 is a flowchart of a method for detecting power of an optical signal according to an embodiment of the present application;

fig. 12 is a flowchart of a method for determining a power of an optical signal under test at a center frequency of an optical carrier according to an embodiment of the present application;

Fig. 13 is a schematic structural diagram of a power detection circuit according to an embodiment of the present application.

Detailed Description

The power detection circuit, system, method and chip for optical signals provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

With the increase of the optical signal transmission rate and the increase of the optical switching dimension, the structure of the optical communication system becomes more and more complex, and the tolerance to the optical signal damage is reduced. In a wavelength division multiplexing (wavelength division multiplexing, WDM) system, such as a Dense WDM (DWDM) system, the power, center wavelength, and signal spectrum shape of each channel need to be monitored to determine if the channels are normal, affect each other, and determine if a device with filtering characteristics in the communication link will cause filtering impairments. Among other things, devices with filtering characteristics may include wavelength selective switches (wavelength selective switch, WSS), wavelength division multiplexers, arrayed waveguide gratings (arrayed waveguide grating, AWG), and the like.

Also, with the large-scale use of optical cross-connect (OXC), the need to monitor parameters of channels in WDM systems is increasing. Based on the parameters monitored in real time, the real-time optimization of the performance of the communication link can be realized by combining the capability of the OXC for adjusting the channel parameters.

The embodiment of the application provides a system and a method for detecting the power of an optical signal, an optical communication system and a chip, and can realize the detection of the power of a service optical signal of each channel in the optical communication system (such as a WDM system or a DWDM system).

Fig. 1 is a schematic structural diagram of an optical communication system according to an embodiment of the present application. As shown in fig. 1, the optical communication system may include: the optical transceiver system comprises a power detection system 000 for optical signals, a first optical transceiver device 100, a second optical transceiver device 200, and at least one optical amplifier (optical amplifier, OA) connected between the first optical transceiver device 100 and the second optical transceiver device 200. For example, three OA's are shown in fig. 1. Wherein each optical transceiver device is connected to the OA and each OA via an optical fiber 300.

The first optical transceiver device 100 may be configured to transmit the optical signal under test, and the at least one OA is configured to amplify the optical signal under test and transmit the amplified optical signal to the second optical transceiver device 200. The measured optical signal may be a wavelength division multiplexing signal, where the wavelength division multiplexing signal includes a plurality of service optical signals with different wavelengths. Alternatively, the optical signal to be measured may be a signal of a single wavelength.

In an embodiment of the present application, the power detection system 000 of the optical signal may be connected to a target device, and the target device may include at least one of the at least one OA, the first optical transceiver apparatus 100, and the second optical transceiver apparatus 200. That is, the target device to which the power detection system 000 of the optical signal is connected may include only one device or may include a plurality of devices. The power detection system 000 may receive the light signal under test emitted by the target device and detect the power of the light signal under test. The power detection system 000 of the optical signal may also be referred to as an optical power detection (optical power monitor, OPM) system.

The optical communication system provided in the embodiments of the present application may include one or more power detection systems 000 for optical signals. For example, the optical communication system shown in fig. 1 includes three optical signal power detection systems 000, wherein each optical signal power detection system 000 is coupled to one OA.

Alternatively, as shown in fig. 1, each of the first and second optical transceiver apparatuses 100 and 200 may include: a plurality of optical signal transceiver units (optical transponder unit, OTU), upper and lower wavelength selective switches (add drop wavelength selective switch, AD WSS), and at least one wavelength selective switch (wavelength selective switch, WSS). For example, two WSSs are shown in fig. 1. Wherein each OUT is configured to transmit and receive a traffic light signal of one wavelength, and the wavelengths of the traffic light signals transmitted (or received) by the respective OUT are different. The AD WSS is configured to implement up-and-down waves of each service optical signal, that is, the AD WSS may be configured to perform wave combination on each service optical signal in the uplink and perform wave division on a wave division multiplexing signal in the downlink. The WSS is used for realizing the routing of the wavelength division multiplexing signals.

The embodiment of the application provides a power detection system for an optical signal, where the power detection system 000 for an optical signal can be applied to an optical communication system as shown in fig. 1. As shown in fig. 2, the power detection system may include: the power detection device 00 of the optical signal and the comb-shaped light source 10.

The comb-shaped light source 10 is configured to emit a local oscillation optical signal LO. The local oscillator optical signal LO comprises N optical carriers, wherein the central frequencies of at least two optical carriers in the N optical carriers are different, and N is an integer larger than 1. For example, the local oscillator optical signal LO includes N optical carriers with different center frequencies.

As shown in fig. 2, the power detection apparatus 00 of the optical signal may include a power detection circuit 01 and a coherent receiver 02.

The coherent receiver 02 is configured to coherently mix the detected optical signal SI and the local oscillation optical signal LO to obtain a mixed optical signal, and transmit the mixed optical signal to the power detection circuit 01. The measured optical signal SI may be a wavelength division multiplexing signal, where the wavelength division multiplexing signal includes a plurality of service optical signals with different wavelengths. Alternatively, the measured optical signal SI may be a signal having a single wavelength.

The power detection circuit 01 is configured to receive the mixed optical signal, filter the mixed optical signal, and determine the power of the detected optical signal at the center frequency of each optical carrier according to the filtered mixed optical signal. The center frequency of each optical carrier is located in the spectrum range of the measured optical signal.

After filtering the mixed optical signal, the power detection circuit 01 can filter out components with the same frequency as each center frequency in the local oscillator optical signal in the detected optical signal, and the rest components are filtered out. Therefore, the power detection circuit 01 can determine the power of the detected optical signal at the center frequency of each optical carrier according to the filtered mixed optical signal.

Because the local oscillator optical signal comprises N optical carriers, and the center frequencies of at least two optical carriers in the N optical carriers are different, after the power detection circuit 01 receives the mixed optical signal obtained by coherently mixing the local oscillator optical signal and the detected optical signal, the parallel detection of the power of the detected optical signal at least two different frequency points can be realized, and thus the efficiency of power detection is effectively improved.

Alternatively, the power detection circuit 01 provided in the embodiment of the present application may be provided independently of the coherent receiver 02. Alternatively, the power detection circuit 01 may be an integrated circuit (integrated circuit, IC), which may also be referred to as an integrated chip, and the power detection circuit 01 may be provided in the coherent receiver 02.

In this embodiment of the present application, for a scenario where the measured optical signal SI is a wavelength division multiplexed signal, the wavelength band of the wavelength division multiplexed signal SI may be a conventional (C) wavelength band (wavelength band), that is, the wavelength range of each service optical signal included in the wavelength division multiplexed signal SI is 1530 nanometers (nm) to 1565nm.

Alternatively, the wavelength band of the wavelength division multiplexed signal SI may be a long (L) band, that is, the wavelength range of each of the service optical signals included in the wavelength division multiplexed signal SI is 1565nm to 1625nm.

Alternatively, the wavelength band of the wavelength division multiplexing signal SI may be a c+l band, that is, the wavelength range of each service optical signal included in the wavelength division multiplexing signal SI is 1530nm to 1625nm.

Optionally, the center frequencies of the N optical carriers are different from each other, and the power detection circuit 01 may be further configured to: the center frequency of each optical carrier in the local oscillation optical signal LO emitted by the comb-shaped optical source 10 is adjusted, so that the center frequency of each optical carrier can be changed in a corresponding frequency spectrum range, and the frequency spectrum ranges corresponding to the center frequencies of different optical carriers are different. The spectrum range corresponding to the center frequency of each optical carrier may be located in the spectrum range of the measured optical signal.

For example, the frequency range corresponding to the center frequency of each optical carrier may include a plurality of frequency points to be detected, and the power detection circuit 01 may adjust the center frequency of each optical carrier, so that the center frequency of each optical carrier can traverse a plurality of frequency points in a corresponding frequency range. The frequency points to be detected in each frequency spectrum range may be stored in advance in the power detection circuit 01.

Because the center frequency of each optical carrier can be changed in a corresponding frequency spectrum range, the number of frequency points detected when the power detection is carried out on the detected optical signals can be effectively increased on the premise of not increasing the number N of the optical carriers. That is, the spectrum shape of the detected optical signal can be accurately detected, and the accuracy of power detection is effectively improved.

As an alternative implementation, as shown in fig. 3, the measured optical signal SI is a wavelength division multiplexed signal, and the wavelength division multiplexed signal SI includes a spectral width Δf _BW N traffic optical signals that are identical but different in wavelength from each other. That is, the number N of optical carriers included in the local oscillation optical signal LO is equal to the number of service optical signals included in the wavelength division multiplexing signal SI. The N optical carriers may be in one-to-one correspondence with the N traffic optical signals. Each service optical signal included in the wavelength division multiplexing signal SI is a signal obtained by modulating a top (pilot tone modulation), and modulation frequencies of different service optical signals are different.

In the above implementation, the power detection circuit 01 may be configured to detect the target frequency interval Δf _Step The center frequency of each optical carrier is adjusted so that the center frequency of each optical carrier can be changed within the frequency spectrum of a corresponding one of the service optical signals. Wherein the target frequency interval Deltaf _Step Less than the spectral width deltaf of the traffic optical signal _BW . Due to the spectral width deltaf of the traffic light signals of different wavelengths _BW The same, so that the power detection circuit 01 can be at a fixed target frequency intervalΔf _Step The center frequency of each optical carrier is adjusted, thereby effectively simplifying the operation of frequency adjustment.

For example, referring to fig. 3, assuming that the wavelength division multiplexing signal SI includes N channels of service optical signals CH1 to CHN, the local oscillator optical signal LO emitted by the comb-shaped optical source 10 may include N optical carriers corresponding to the N service optical signals one by one. The center frequency of each optical carrier is located within and can vary within the spectral range of a corresponding one of the traffic optical signals. For example, the center frequency f of the first optical carrier _c1 Can vary within the spectral range of the first traffic light signal CH 1. Center frequency f of Nth optical carrier _cN Can vary within the spectral range of the nth traffic optical signal CHN.

Alternatively, in the above implementation, the frequency difference between the center frequencies of two adjacent optical carriers may be equal to the spectral width Δf of the traffic optical signal _BW . For example, in FIG. 3, the center frequency f of the first optical carrier _C1 F with the center frequency of the second optical carrier _C2 Is equal to deltaf _BW . In fig. 3, for clarity of illustration, the spectrum intervals of each service optical signal are plotted, and in practical application, the spectrums of adjacent service optical signals may partially overlap.

As another alternative implementation manner, the measured optical signal SI is a wavelength division multiplexing signal, where the wavelength division multiplexing signal SI includes a plurality of service optical signals with different wavelengths, and spectral widths of at least two service optical signals in the plurality of service optical signals are different. Each service optical signal may include at least one slice signal, and each slice signal is a signal obtained by modulating the top. The frequency spectrum widths of the N slice signals are the same, and the modulation frequencies of different slice signals are different, i.e., the modulation frequencies of any two slice signals are different. In this implementation, N is the total number of slice signals included in the wavelength division multiplexing signal SI, and accordingly, the N optical carriers may be in one-to-one correspondence with the N slice signals.

Alternatively, the spectral width of the slice signal may be determined according to the spectral width of each of the traffic light signals, and the spectral width of the slice signal is not greater than the spectral width of any of the traffic light signals. For example, the spectral width of the sliced signal may be the greatest common divisor of the spectral width of the individual traffic light signals. As shown in fig. 5, if the spectral width of the service optical signal CNn of the nth channel in the wavelength division multiplexed signal SI is three times the greatest common divisor, the service optical signal CNn may be divided into three slice signals CHn1, CHn2 and CHn3 having the same spectral width. The three slice signals are signals obtained by modulating the top by adopting different modulation frequencies. Wherein n is a positive integer, and n is not greater than the number of service optical signals included in the wavelength division multiplexing signal SI.

For example, assuming that the wavelength division multiplexing signal SI includes a plurality of service optical signals, a spectrum width of a portion of the service optical signals is 50 gigahertz (GHz), a spectrum width of a portion of the service optical signals is 75GHz, and a spectrum width of a portion of the service optical signals is 100GHz, the spectrum width of the slicing signal may be 25GHz. Accordingly, each of the service optical signals having a spectral width of 50GHz may be sliced into two 25GHz sliced signals, each of the service optical signals having a spectral width of 75GHz may be sliced into three 25GHz sliced signals, and each of the service optical signals having a spectral width of 100GHz may be sliced into four 25GHz sliced signals.

In the above implementation, the power detection circuit 01 is configured to adjust the center frequency of each optical carrier according to the target frequency interval, so that the center frequency of each optical carrier can be changed within a frequency spectrum range corresponding to one slice signal. Wherein the target frequency interval is smaller than the spectral width of the slice signal.

In the scenario that the spectrum widths of the service optical signals included in the wavelength division multiplexing signal SI are not identical, the scheme provided by the embodiment of the present application may slice and adjust the top of the service optical signal in the process of performing electro-optical modulation on the service optical signal to generate the service optical signal, so that the finally generated service optical signal includes a plurality of slice signals with identical spectrum widths. Because the frequency spectrum widths of the slicing signals are the same, the central frequencies of the N optical carriers can be uniformly adjusted according to the same frequency interval (namely the target frequency interval), so that the parallel detection of the power of the N slicing signals is realized, and the complexity in adjusting the central frequencies of the plurality of optical carriers is effectively simplified.

In the embodiment of the present application, the process of slicing the service electrical signal and then adjusting the top of the sliced electrical signal may also be referred to as slice adjustment. The implementation process of slicing and topping the service electrical signal to generate the service optical signal may refer to fig. 5. As shown in fig. 5, a fast fourier transform (fast Fourier transform, FFT) is required to first perform the service electrical signal in the time domain to transform the service electrical signal into the frequency domain. And then slicing the service electric signal in the frequency domain to obtain a plurality of slices. For example, as shown in fig. 5, assuming that the spectral width of the traffic optical signal to be generated is L times (L is an integer greater than 1) the greatest common divisor of the spectral widths of the respective traffic optical signals, the traffic electric signal of the frequency domain may be sliced into L slices. Thereafter, an Inverse Fast Fourier Transform (IFFT) is performed on each slice to transform each slice to the time domain. Then, for each slice, the slice may be multiplied by a corresponding roofing factor by a multiplier to achieve roofing of the slice. Wherein, the top-adjusting coefficient k adopted when the top of the first slice in the L slices is adjusted _l Can satisfy the following conditions: a, a _l ·cos(2π·f _Pl ·t)+(1-a _l ). Wherein a is _l To adjust the top depth when the top of the first slice is adjusted, f _Pl For the modulation frequency when the first slice is topped, L is a positive integer not greater than L.

Further, the L slices after the topping may be superimposed by an adder, the superimposed slices may be converted into an analog signal by a digital-to-analog converter (DAC), and the analog signal may be output to the optical modulator. Finally, the optical modulator may modulate the analog signal with a traffic optical carrier to generate a traffic optical signal. For example, referring to fig. 5, assuming that the traffic optical signal to be generated is the traffic optical signal of the nth channel, the optical modulator may employ a center frequency f _Sn The analog signal is modulated by the service optical carrier wave of (2) to obtain the center frequency f _Sn Is of (1)A signal.

As still another optional implementation manner, the local oscillator optical signal includes N optical carriers, where each optical carrier is a signal obtained by modulating the top, and modulation frequencies of different optical carriers are different. In this implementation, the power detection circuit 01 may be configured to adjust the center frequency of each optical carrier at a target frequency interval, such that the center frequency of each optical carrier can vary within a corresponding one of the spectral ranges. The width of the spectrum range corresponding to the center frequency of each optical carrier may be equal to the frequency difference between the center frequencies of the adjacent two optical carriers. Accordingly, the target frequency interval is smaller than the frequency difference of the center frequencies of the adjacent two optical carriers.

In this implementation, the number N of optical carriers included in the local oscillation optical signal is independent of the type of the optical signal to be measured. That is, if the optical signal to be measured is a wavelength division multiplexed signal, the number N of optical carriers is independent of the number of service optical signals included in the wavelength division multiplexed signal. The spectrum range corresponding to the center frequency of each optical carrier is irrelevant to the spectrum range of any service optical signal, and only the set of the spectrum ranges corresponding to the center frequencies of the N optical carriers is required to be ensured, so that the spectrum range of the measured optical signal can be covered. Since the power detection circuit 01 can adjust the center frequency of each optical carrier at fixed target frequency intervals, the frequency adjustment operation is effectively simplified.

In addition, the implementation mode for adjusting the top of the optical carrier can also reduce the requirement of the detected optical signal to be detected. For example, if the optical signal to be measured is a wavelength division multiplexed signal, even if each service optical signal included in the wavelength division multiplexed signal does not undergo topping, or the spectrum widths of the service optical signals are different, effective detection of the power of each service optical signal can be achieved based on the optical carrier after topping.

Based on the above-mentioned exemplary implementations, the solution provided in the embodiment of the present application may perform topping on N service optical signals, or may perform topping on N slice signals, or may further perform topping on N optical carriers, respectively. The top modulation is a signal modulation technology, which can superimpose a low-frequency sine signal or a low-frequency cosine signal with small amplitude on the top of an optical signal with each wavelength at a signal transmitting end to serve as an identifier of the optical signal. The frequency of the low-frequency sine signal or the low-frequency cosine signal is the modulation frequency of the modulated top, and the modulation frequencies adopted when the modulated top is carried out on different optical signals are different. The power detection circuit 01 can further determine optical signals of different wavelengths based on the modulation frequency, and detect the power of the different optical signals.

For example, assuming that the measured optical signal is a wavelength division multiplexing signal including N service optical signals, and each service optical signal is a signal subjected to topping, the formula of the intensity of the ith service optical signal subjected to topping according to the time t may be:

wherein a is _i The value range of the peak modulation depth for the ith service optical signal is generally 0.01<a _i <0.1. The crest depth of each service optical signal can be the same or different. A is that _Si For the intensity of the ith service optical signal, f _Si For the center frequency of the ith traffic optical signal,is the phase of the ith traffic optical signal and is a time variable. f (f) _Pi The modulation frequency is used for carrying out roof-lifting on the ith service optical signal. j is an imaginary unit. Because the modulation frequency adopted when the top of the optical signals of different services is modulated is different, when i is not equal to k, f _Pi ≠f _Pk . Wherein i and k are positive integers not greater than N.

The formula of the intensity of the wavelength division multiplexing signal obtained after the combination of the N business optical signals with different wavelengths along with the time t is as follows:based on the formula, the intensity of the wavelength division multiplexing signal is equal to the intensity of the N service optical signalsAnd (5) the sum of the degrees.

Optionally, in this embodiment of the present application, the power detection circuit 01 may adjust the center frequency of each optical carrier in the local oscillation optical signal emitted by the comb-shaped optical source according to the order of the center frequency from low to high, so that the center frequency can traverse a plurality of frequency points to be detected in a corresponding frequency spectrum range.

In this adjustment mode, the initial value of the center frequency of each optical carrier may be equal to a difference between the center frequency of the corresponding one of the spectral ranges and half the width of the spectral range. Assume that the measured optical signal is a wavelength division multiplexing signal, and the wavelength division multiplexing signal comprises N frequency spectrum widths delta f _BW And the center frequency of each optical carrier corresponds to the spectrum range of one service optical signal, the initial value f of the center frequency of the ith optical carrier _Ci-0 Can satisfy the following conditions:

f _Ci-0 ＝f _Si -Δf _BW /2；

wherein f _Si The center frequency of the ith service optical signal is represented, i is a positive integer not greater than N.

As shown in fig. 6, it is assumed that m+1 frequency points to be detected are included in the spectrum range of each service optical signal, where M is a positive integer. The power detection circuit 01 may start from an initial value of the center frequency of each optical carrier at a target frequency interval deltaf _Step And adjusting the center frequency of each optical carrier for M times, so that the center frequency of each optical carrier can traverse the M+1 frequency points to be detected. Since the M+1 frequency points to be detected are all located in the spectral range of the service optical signal, the target frequency interval Δf _Step And the spectral width Deltaf of each traffic light signal _BW The following relation may be satisfied: Δf _BW ≤M×Δf _Step 。

For example, for a first optical carrier, the power detection circuit 01 may set the center frequency f of the first optical carrier _C1-0 The method comprises the following steps: f (f) _C1-0 ＝f _S1 -Δf _BW /2. After that, the power detection circuit 01 can perform the power detection at the target frequency interval Δf _Step Step by step to step increase the firstThe center frequency of the optical carrier. After the power detection circuit adjusts the center frequency of the first optical carrier for the mth time, the center frequency of the first optical carrier is f _C1-m ＝f _C1-0 +m×Δf _Step . The M is a positive integer not greater than M.

Or, the power detection circuit 01 may further adjust the center frequency of each optical carrier in the local oscillation optical signal emitted by the comb-shaped optical source according to the order from the high center frequency to the low center frequency, so that the center frequency can traverse a plurality of frequency points to be detected in a corresponding frequency spectrum range.

In this adjustment mode, the initial value of the center frequency of each optical carrier may be equal to the sum of the center frequency of the corresponding one of the spectrum ranges and half the width of the spectrum range. Assume that the measured optical signal is a wavelength division multiplexing signal, and the wavelength division multiplexing signal comprises N frequency spectrum widths delta f _BW And the center frequency of each optical carrier corresponds to the spectrum range of one service optical signal, the initial value f of the center frequency of the ith optical carrier _Ci-0 Can satisfy the following conditions: f (f) _Ci-0 ＝f _Si +Δf _BW /2。

Of course, the power detection circuit 01 may also adjust the center frequency of each optical carrier in the local oscillation optical signal according to other sequences, so long as the center frequency can traverse a plurality of frequency points to be detected in a corresponding frequency spectrum range.

In the embodiment of the present application, the mixed optical signal output by the coherent receiver 02 may include four components, which are in-phase components I of the first polarization component _x Quadrature component Q of the first polarization component _x In-phase component I of the second polarization component _y Quadrature component Q of the second polarization component _y 。

Alternatively, as shown in fig. 7, the power detection circuit 01 may include: a low-pass filter 011, an operator 012, a comb filter 013, and a power detection sub-circuit 014.

The low-pass filter 011 is configured to perform low-pass filtering on the four components, respectively. Since the four components can be low-pass filtered separately, the low-pass filter 011 can also be referred to as a four-channel low-pass filter. After the low-pass filter 011 performs low-pass filtering on the four components, the components with the same frequency as the center frequency of the local oscillator optical signal in the measured optical signal can be filtered out, and the other components are filtered out. In the embodiment of the application, the center frequency of the top adjusting signal is low and is smaller than the cut-off frequency of the low-pass filter, so that the operation of the low-pass filter has no influence on top adjustment.

The low pass filter 011 applies to the four components I _x 、Q _x 、I _y Q and _y after low pass filtering, the four components can be expressed as:

wherein I is _x-LP (t) is the low-pass filtered component I _x ，Q _x-LP (t) is the low-pass filtered component Q _x ，I _y-LP (t) is the low-pass filtered component I _y ，Q _y-LP (t) is the low-pass filtered component Q _y 。f _Pi Representing the modulation frequency employed when the ith optical signal (which may be a traffic optical signal, a slicing signal or an optical carrier) is modulated, i.e., the ith modulation frequency. a, a _i The peak modulation depth when the ith optical signal is modulated, i.e. the ith modulation depth, may be the same or different. A is that _Si-x (f _Ci ) Indicating the frequency f in the measured optical signal _Ci Intensity of x-polarized component of frequency component (i.e. center frequency of ith optical carrier), A _Si-y (f _Ci ) Indicating the frequency f in the measured optical signal _Ci The intensity of the y-polarized component of the frequency component of (c).Indicating the frequency f in the measured optical signal _Ci The phase of the x-polarized component of the frequency component of (c),representing the measured objectThe frequency in the optical signal is f _Ci The phase of the y-polarized component of the frequency component of (c).

The operator 012 is used to determine the power of the four components after low pass filtering. For example, the operator 012 may determine the square of each component after low-pass filtering and then sum the squares of the four components to obtain the power of the four components. That is, the power of the four components refers to the total power of the four components. The operator 012 may also be referred to as a sum-of-squares operator. The equation for the power of the four components after low pass filtering over time t can be expressed as:

Wherein, the liquid crystal display device comprises a liquid crystal display device,

/>

in the above expression, k is a positive integer not greater than N, and k+.i. f (f) _Ck Is the center frequency of the kth optical carrier. Due toAnd->Are random, so that the second and third terms in the expression of power can be understood as random noise.

The comb filter 013 is used for performing comb filtering on the power of the four components. Wherein the comb shapeThe number of pass bands of the filter 013 may be greater than or equal to N, and the center frequency of each pass band is equal to one modulation frequency. That is, the center frequencies of at least N pass bands of the comb filter 013 are f _P1 、f _P2 …f _PN . After the comb filter 013 is adopted to comb-filter the power of the four components, random noise in the power can be filtered. The output of the comb filter 013 can be expressed as:

the power detection sub-circuit 014 is configured to determine the power of the comb-filtered power of the four components at each modulation frequency, obtain a modulated top power corresponding to each modulation frequency, and determine the power of the measured optical signal at the center frequency of the optical carrier according to the modulated top power corresponding to each modulation frequency, the intensity of the optical carrier corresponding to the modulation frequency, and the modulated top depth corresponding to the modulation frequency. The power of the measured optical signal at the center frequency of the optical carrier is positively correlated with the peak-to-peak power, and negatively correlated with both the intensity of the optical carrier and the peak-to-peak depth.

Wherein, when the measured optical signal is a wavelength division multiplexing signal, and the N service optical signals included in the wavelength division multiplexing signal are respectively modulated, the optical carrier corresponding to the modulation frequency refers to: an optical carrier whose center frequency varies within the spectral range of the traffic optical signal modulated with the modulation frequency. For example, it is assumed that the center frequency of the ith optical carrier changes within the spectrum of the ith service optical signal, and the modulation frequency used when the ith service optical signal is modulated is f _Pi The modulation frequency f _Pi The corresponding optical carrier is the ith optical carrier.

In a scenario where the measured optical signal is a wavelength division multiplexing signal and N slice signals included in the wavelength division multiplexing signal are modulated respectively, an optical carrier corresponding to a modulation frequency refers to: an optical carrier whose center frequency varies within the spectral range of the sliced signal modulated with the modulation frequency. For example, assume the ith optical carrierThe center frequency of the (i) th slice signal is changed in the spectrum range of the (i) th slice signal, and the modulation frequency adopted when the (i) th slice signal is subjected to roof-adjusting is f _Pi The modulation frequency f _Pi The corresponding optical carrier is the ith optical carrier.

In the scenario of performing top modulation on N optical carriers, the optical carrier corresponding to the modulation frequency refers to: the modulated optical carrier is used. For example, assume that the modulation frequency used in topping the ith optical carrier is f _Pi The modulation frequency f _Pi The corresponding optical carrier is the ith optical carrier.

Alternatively, as shown in fig. 7, the power detection sub-circuit 014 may include: a power detection module 0141, a spectral shape recovery module 0142 and a controller 0143. The input of the power detection module 0141 is connected to the output of the comb filter 013, and the power detection module 0141 can perform FFT on the comb-filtered power of the four components to convert the comb-filtered power to the frequency domain. Then, the power detection module 0141 detects that the frequencies in the frequency domain are f _P1 、f _P2 …f _PN The power at that point, i.e., the power at each modulation frequency in the frequency domain is detected. The power at each modulation frequency is the modulated top power corresponding to the modulation frequency. The N peak powers detected by the power detection module 0141 are P _P1 、P _P2 …P _PN . The ith modulated top power P of the N modulated top powers _Pi Can be expressed as:

the spectrum recovering module 0142 can obtain the center frequencies f of N optical carriers in the local oscillation optical signal outputted from the comb-like optical source 10 from the controller 0143 _C1 、f _C2 …f _CN And the intensities A of the N optical carriers _C1 、A _C2 …A _CN . The spectrum shape recovery module 0142 may output N peak-to-peak powers P to the power detection module 0141 based on the center frequency and intensity of the acquired optical carrier _P1 、P _P2 …P _PN Respectively enterAnd calculating the row to obtain the power of the measured optical signal at the center frequency of each optical carrier. For example, the spectral shape recovery module 0142 uses the peak modulation depth a corresponding to the ith modulation frequency _i The intensity A of the ith optical carrier _Ci For the ith modulated top power P _Pi Calculating to obtain the center frequency f of the measured optical signal in the ith optical carrier _Ci Power P of the output _S (f _Ci )：

The spectrum recovering module 0142 determines the power of the detected optical signal at the center frequency of each optical carrier based on the above manner, and records the center frequencies f of the N optical carriers _C1 、f _C2 …f _CN And the N powers P _S (f _C1 )、P _S (f _C2 )、…P _S (f _CN ) Corresponding relation of (3). For example, the spectral shape recovery module 0142 may generate a two-dimensional array to record the correspondence of the center frequency to power.

Fig. 8 is a schematic structural diagram of still another power detection system according to the embodiment of the present application, and as can be seen in conjunction with fig. 7 and 8, the operator 012, the comb filter 013, and the power detection sub-circuit 014 in the power detection circuit 01 may all be integrated into a microprocessor. For example, referring to fig. 8, the microprocessor may be a micro control unit (micro controller unit, MCU).

Optionally, as shown in fig. 8, the power detection apparatus may further include an analog-to-digital converter (ADC) 03 and a memory 04. The ADC 03 is connected to the low-pass filter 011 and the MCU, respectively, and is configured to perform analog-to-digital conversion on each component output by the low-pass filter 011, and transmit the data after analog-to-digital conversion to the MCU. The memory 04 may be used to store the center frequency and intensity of each optical carrier in the local oscillation light emitted by the comb-shaped light source 10, and the correspondence between each optical carrier and each service optical signal.

In the embodiment of the present application, the memory 04 may be provided independently of the MCU, or may be integrated in the MCU, i.e. the memory 04 may be an internal memory of the MCU.

Alternatively, in the embodiment of the present application, the low-pass filter 011, the operator 012, the ADC 03, the comb filter 013, and the power detection sub-circuit 014 may be integrated in the microprocessor. I.e. the power detection circuit 01 may be an integrated circuit. For example, the power detection circuit 01 may be a digital signal processor (digital signal processor, DSP).

In the embodiment of the present application, as shown in fig. 8, the comb-shaped light source 10 may include a frequency comb-shaped light source 101 with an adjustable frequency. Alternatively, as shown in fig. 9, the comb-shaped light source 10 may include a plurality of frequency comb-shaped light sources 101 having different wavelength bands from each other, and a combiner 102. For example, two frequency comb light sources 101 are shown in fig. 9. The combiner 102 is configured to combine the optical carriers of different wavebands emitted by the plurality of frequency comb light sources 101 to obtain the local oscillation optical signal.

Alternatively, if the band occupied by the measured optical signal is narrow, the comb-like optical source 10 may include only one frequency comb-like optical source 101 with an adjustable frequency, so as to reduce the cost and volume of the comb-like optical source 10. For example, if the wavelength of the measured optical signal belongs to the C-band, the comb-like optical source 10 may include a C-band frequency comb-like optical source 101. If the wavelength of the detected optical signal belongs to the L-band, the comb-like optical source 10 may include an L-band frequency comb-like optical source 101.

If the band occupied by the detected optical signal is wider, the comb-like light source 10 may include a plurality of frequency comb light sources 101 with different bands, so as to cover the band occupied by the detected optical signal, thereby realizing effective detection of the power of the detected optical signal. For example, if the measured optical signal occupies the C-band and the L-band, the comb-shaped optical source 10 may include a C-band frequency comb optical source 101 and an L-band frequency comb optical source 101 as shown in fig. 9.

Fig. 10 is a schematic structural diagram of still another power detection system according to an embodiment of the present application. For the scenario where the N optical carriers are modulated signals, as shown in fig. 10, the comb light source 10 may include at least one frequency comb light source 101, and a modulated signal circuit 103. Only one frequency comb light source 101 is schematically shown in fig. 10. The topping circuit 103 is configured to perform topping on each optical carrier output by the at least one frequency comb light source 101.

Alternatively, as shown in fig. 10, the topping circuit 103 may include a demultiplexer 1031, N intensity modulators 1032, and a multiplexer 1033. The demultiplexer 1031 is configured to demultiplex the N optical carriers outputted from the at least one frequency comb light source 101 to output each optical carrier to one intensity modulator 1032. Each intensity modulator 1032 is configured to modulate a received optical carrier with a modulation frequency, and the modulation frequencies employed by different intensity modulators 1032 are different. The combiner 1033 is configured to combine the modulated optical carriers output by the N intensity modulators 1032, and output the combined N optical carriers (i.e., the local oscillation optical signals L0) to the coherent receiver 02.

According to the power detection circuit and the power detection system, parallel detection of power of the detected optical signals at the N central frequencies can be achieved through the N optical carriers output by the comb-shaped optical source. Therefore, the time required by power detection is effectively shortened, and the efficiency of power detection is improved. When the band occupied by the detected optical signal is wider, i.e. the spectrum width is wider (for example, reaching 100 nm), the power detection circuit and the power detection speed of the system provided by the embodiment of the application can meet the detection requirement on the burst spectrum event.

The burst spectrum event means that the spectrum of the service optical signal returns to normal after being changed in a short time. Because the duration of the burst spectrum event is shorter, if the power detection speed of the power detection system is slower, the burst spectrum event cannot be effectively detected.

For example, if the optical signal to be measured is a wavelength division multiplexing signal, the wavelength division multiplexing signal includes N (N may be 100 or 200) service optical signals with different wavelengths, where m+1 frequency points to be detected exist in the service optical signal of each wavelength. The power detection system provided by the embodiment of the application needs to repeat the power detection process for m+1 times, so that the power detection of the N service optical signals can be completed. By adopting the method in the related art, the power detection process needs to be repeated for n× (m+1) times to complete the power detection of the N service optical signals. Therefore, compared with the power detection method in the related art, the power detection circuit and the system provided by the embodiment of the application can increase the power detection speed by N times.

In summary, the embodiment of the present application provides a power detection system for an optical signal, where a local oscillation optical signal output by a comb-shaped optical source in the power detection system includes N optical carriers, and center frequencies of at least two optical carriers in the N optical carriers are different. After the local oscillation optical signal and the measured optical signal are coherently mixed, the parallel detection of the power of the measured optical signal at least two different frequency points can be realized, so that the efficiency of power detection is effectively improved. In addition, the power detection circuit in the power detection system can also adjust the center frequency of each optical carrier in a frequency spectrum range corresponding to each optical carrier, so that the power detection of a plurality of frequency points of the detected optical signal in each frequency spectrum range can be realized, the power detection precision of the detected optical signal can be effectively improved, and the spectrum shape detection of the detected optical signal can be realized.

The embodiment of the application also provides a method for detecting the power of the optical signal, which can be applied to the power detection circuit 01 of the optical signal provided by the embodiment. Referring to fig. 11, the method may include:

step 201, a mixed optical signal is received.

The mixed optical signal is obtained by coherently mixing the measured optical signal and the local oscillation optical signal. The local oscillator optical signal comprises N optical carriers, the center frequencies of at least two optical carriers in the N optical carriers are different, and N is an integer larger than 1. The optical signal to be measured may be a wavelength division multiplexed signal including a plurality of service optical signals having different wavelengths, or may be a service optical signal having a single wavelength. Referring to fig. 1, the measured optical signal is emitted from a target device to which a power detection system 000 of the optical signal is connected.

Referring to fig. 2, the power detection system for an optical signal includes a coherent receiver 02, where the coherent receiver 02 may be configured to coherently mix an optical signal to be detected with a local oscillator optical signal to obtain a mixed optical signal, and send the mixed optical signal to the power detection circuit 01. That is, the power detection circuit 01 can receive the mixed optical signal transmitted by the coherent receiver 02.

Step 202, filtering the mixed optical signal.

After the mixed optical signal is filtered, the components with the same frequency as the central frequencies in the local oscillation optical signal in the detected optical signal can be filtered, and the rest components are filtered.

Step 203, determining the power of the measured optical signal at the center frequency of each optical carrier according to the filtered mixed optical signal.

Because the local oscillator optical signal includes N optical carriers, and the center frequencies of at least two optical carriers in the N optical carriers are different, parallel detection of the power of the detected optical signal at least two different center frequencies can be achieved based on the methods of steps 201 to 203.

Step 204, detecting whether the center frequency of each optical carrier traverses a plurality of frequency points to be detected in a corresponding frequency spectrum range in the local oscillation optical signal.

In this embodiment of the present application, the power detection circuit 01 may further adjust a center frequency of each optical carrier, so that the center frequency of each optical carrier can traverse a plurality of frequency points to be detected in a corresponding frequency spectrum range. Wherein the frequency spectrum ranges corresponding to the center frequencies of different optical carriers are different.

If the power detection circuit 01 detects that the center frequency of each optical carrier has traversed a plurality of frequency points to be detected in a corresponding frequency spectrum range, it may be determined that the power detection of the detected optical signal has been completed, and the operation is ended. If the power detection circuit 01 detects that the center frequency of each optical carrier has not traversed a plurality of frequency points to be detected in a corresponding frequency spectrum range, step 205 may be performed.

Step 205, adjusting the center frequency of each optical carrier in a frequency spectrum range corresponding to the optical carrier.

If the power detection circuit 01 detects that the center frequency of each optical carrier does not traverse the multiple frequency points to be detected in the corresponding one of the frequency spectrum ranges, the power detection circuit 01 may adjust the center frequency of the optical carrier in the corresponding one of the frequency spectrum ranges of each optical carrier. Thereafter, the above-described step 201 may be continued. That is, in the embodiment of the present application, the power detection circuit 01 of the optical signal may repeatedly perform the steps 201 to 205 until the center frequency of each optical carrier traverses a plurality of frequency points to be detected in a corresponding frequency spectrum range.

For example, assuming that each optical carrier includes m+1 frequency points to be detected in a spectral range corresponding to the center frequency of each optical carrier, the power detection circuit 01 of the optical signal may repeatedly perform steps 201 to 205 for m+1 times, so as to implement spectrum shape detection of the detected optical signal.

The implementation of steps 201 to 205 may be described with reference to the description of the power detection circuit 01.

As an alternative implementation manner, the optical signal to be measured is a wavelength division multiplexing signal, and the wavelength division multiplexing signal includes N service optical signals with the same frequency spectrum width but different wavelengths. Each service optical signal is a signal obtained by modulating the top, and the modulation frequencies of different service optical signals are different. Accordingly, the step 205 may include:

and adjusting the center frequency of each optical carrier in the local oscillation optical signal according to the target frequency interval, so that the center frequency of each optical carrier is changed in the frequency spectrum range of one service optical signal. Wherein the target frequency interval is smaller than the spectral width of the traffic light signal.

As another optional implementation manner, the measured optical signal is a wavelength division multiplexing signal, the wavelength division multiplexing signal includes a plurality of service optical signals with different wavelengths, and spectrum widths of at least two service optical signals in the plurality of service optical signals are different. Each service optical signal comprises at least one slice signal, and each slice signal is a signal obtained by modulating the top. The N slice signals have the same spectral width and the modulation frequencies of the different slice signals are different. In this implementation, N is the total number of slice signals that the wavelength division multiplexed signal includes. Accordingly, the step 205 may include:

And adjusting the center frequency of each optical carrier according to the target frequency interval, so that the center frequency of each optical carrier is changed in the frequency spectrum range of one slice signal. Wherein the target frequency interval is smaller than the spectral width of the slice signal.

As a further alternative implementation manner, each optical carrier is a signal obtained by modulating the top, and the modulation frequencies of different optical carriers are different; accordingly, the step 205 may include:

the center frequency of each optical carrier is adjusted according to a target frequency interval that is less than the frequency difference of the center frequencies of adjacent two optical carriers.

Optionally, the mixed optical signal comprises four components, which are respectively a quadrature component of the first polarization component, an in-phase component of the first polarization component, a quadrature component of the second polarization component, and an in-phase component of the second polarization component.

The step 202 may include: the four components are low pass filtered separately. Referring to fig. 7, the power detection circuit 01 may include a low pass filter 011, the low pass filter 011 is used to perform the steps 201 and 202, and thus the implementation of the steps 201 and 202 may be described with reference to the low pass filter 011.

Fig. 12 is a flowchart of a method for determining a power of an optical signal under test at a center frequency of an optical carrier according to an embodiment of the present application. As shown in fig. 12, the step 203 may include:

step 2031, determining the power of the four components after the low pass filtering.

In the embodiment of the present application, the power detection circuit 01 may calculate the sum of squares of the four components after the low-pass filtering as the power of the four components. I.e. the power of the four components refers to the total power of the four components. Referring to fig. 7, the power detection circuit 01 may further include an operator 012, and the operator 012 is configured to perform the step 2031, so that the implementation process of the step 2031 may refer to the above description about the operator 012.

Step 2032, comb filtering the power of the four components with a comb filter having a plurality of pass bands, each pass band having a center frequency equal to one of the modulation frequencies.

After the comb filter is used for carrying out comb filtering on the power of the four components, random noise in the power can be filtered. The implementation of this step 2032 may be referred to the above description of comb filter 013.

Step 2033, determining the power of the comb-filtered power of the four components at each modulation frequency, to obtain the peak modulation power corresponding to each modulation frequency.

In this embodiment of the present application, the power of the four components after comb filtering may be first subjected to FFT to convert the comb filtered power into the frequency domain, and then the frequencies in the frequency domain may be detected as f _P1 、f _P2 …f _PN The power at that point, i.e., the power at each modulation frequency in the frequency domain is detected. Referring to fig. 7, the power detection circuit 01 further includes a power detection subcircuit 014, the power detection subcircuit 014 including a power detection module 0141. The implementation of this step 2033 may be described with reference to the relevant description of the power detection module 0141 above.

Step 2034, determining the power of the measured optical signal at the center frequency of the optical carrier according to the peak modulation power corresponding to each modulation frequency, the intensity of the optical carrier corresponding to the modulation frequency, and the peak modulation depth corresponding to the modulation frequency.

The power of the measured optical signal at the center frequency of the optical carrier is positively correlated with the peak-to-peak power, and negatively correlated with both the intensity of the optical carrier and the peak-to-peak depth. Referring to fig. 7, the power detection subcircuit 014 also includes a spectral shape restoration module 0142. The implementation of this step 2034 may be described with reference to the spectral shape recovery module 0142 above.

Optionally, the N modulation frequenciesThe i modulation frequencies correspond to the i-th optical carrier of the N optical carriers, and the measured optical signal is at the center frequency f of the i-th optical carrier _Ci The power at this point satisfies:

Optionally, the sequence of the steps of the method for detecting the power of the optical signal provided in the embodiment of the present application may be appropriately adjusted, and the steps may also be correspondingly increased or decreased according to the situation. For example, the above steps 204 and 205 may be deleted as the case may be. Any method that can be easily conceived by those skilled in the art within the technical scope of the present disclosure should be covered in the protection scope of the present application, and thus will not be repeated.

In summary, the embodiments of the present application provide a method for detecting power of an optical signal, which may receive a mixed optical signal obtained by coherently mixing a local oscillation optical signal and a measured optical signal. Because the central frequencies of at least two optical carriers in the N optical carriers included in the local oscillation optical signal are different, the parallel detection of the power of the detected optical signal at least two different frequency points can be realized based on the mixed optical signal, and the efficiency of power detection is effectively improved.

In addition, the method can also adjust the center frequency of each optical carrier in a frequency spectrum range corresponding to each optical carrier, so that the power detection of a plurality of frequency points of the detected optical signal in each frequency spectrum range can be realized, the power detection precision of the detected optical signal can be effectively improved, and the spectrum shape detection of the detected optical signal can be realized.

It will be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific implementation process of the above-described power detection method of an optical signal may refer to the related description in the foregoing power detection system and the power detection circuit embodiment of the optical signal, which are not repeated herein.

It should be appreciated that the power detection circuit for optical signals provided by embodiments of the present application may also be implemented as an application-specific integrated circuit (ASIC), a programmable logic device (programmable logic device, PLD), which may be a complex program logic device (complex programmable logical device, CPLD), a field-programmable gate array (FPGA), general-purpose array logic (generic array logic, GAL), or any combination thereof. The power detection method provided by the method embodiment can also be implemented by software, and when the power detection method provided by the method embodiment is implemented by software, each device and sub-circuit in the power detection circuit can also be a software module.

The embodiment of the application also provides an optical communication system, as shown in fig. 1, which includes: at least one power detection system 000 for optical signals, a first optical transceiver device 100, a second optical transceiver device 200, and at least one OA connected between the first optical transceiver device 100 and the second optical transceiver device 200, as provided in the above embodiments.

The coherent receiver 02 in the power detection system 000 is connected to a target device, the target device including at least one of the at least one OA, the first optical transceiver apparatus 100 and the second optical transceiver apparatus 200, and the coherent receiver 02 is configured to receive the optical signal under test transmitted by the target device.

Alternatively, the optical communication system may be a WDM or DWDM system.

Fig. 13 is a schematic structural diagram of a power detection circuit according to an embodiment of the present application, where the power detection circuit may be applied to the power detection system of the optical signal according to the above embodiment. Referring to fig. 13, the power detection circuit may include: processor 1301, memory 1302, transceiver 1303, and bus 1304. Wherein a bus 1304 is used to connect the processor 1301, the memory 1302 and the transceiver 1303. Communication connections with other devices may be made through transceiver 1303 (which may be wired or wireless). The memory 1302 stores therein a computer program for realizing various application functions.

It should be appreciated that in embodiments of the present application, the processor 1301 may be a central processing unit (central processing unit, CPU), the processor 1301 may also be other general purpose processors, digital Signal Processors (DSPs), application Specific Integrated Circuits (ASICs), field Programmable Gate Arrays (FPGAs), GPUs or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general purpose processor may be a microprocessor or any conventional processor or the like.

The memory 1302 may be volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memory. The nonvolatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. The volatile memory may be random access memory (random access memory, RAM) which acts as an external cache. By way of example, and not limitation, many forms of RAM are available, such as Static RAM (SRAM), dynamic Random Access Memory (DRAM), synchronous Dynamic Random Access Memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous Link DRAM (SLDRAM), and direct memory bus RAM (DR RAM).

The bus 1304 may include a power bus, a control bus, a status signal bus, and the like, in addition to a data bus. But for clarity of illustration, the various buses are labeled as bus 1304 in the figures.

Processor 1301 is configured to execute a computer program 13021 stored in memory 1302. The processor 1301 implements the power detection method provided by the above embodiment by executing the computer program 13021. For example, the methods shown in steps 201 to 205 and the methods shown in steps 2031 to 2034 in the above-described method embodiments may be implemented.

The embodiments of the present application also provide a computer readable storage medium having instructions stored therein, which when run on a computer, cause the computer to implement the power detection method provided in the above embodiments. For example, the methods shown in steps 201 to 205 and the methods shown in steps 2031 to 2034 in the above-described method embodiments may be performed.

The present embodiments also provide a computer program product containing instructions which, when run on a computer, cause the computer to implement the power detection method as provided in the above embodiments. For example, the methods shown in steps 201 to 205 and the methods shown in steps 2031 to 2034 in the above-described method embodiments may be performed.

The embodiment of the application also provides a chip, which comprises a programmable logic circuit and/or program instructions and is used for realizing the power detection method provided by the embodiment when the chip runs. For example, the methods shown in steps 201 to 205 and the methods shown in steps 2031 to 2034 in the above-described method embodiments may be performed.

The above embodiments may be implemented in whole or in part by software, hardware, firmware, or any other combination. When implemented in software, the above-described embodiments may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded or executed on a computer, produces a flow or function in accordance with embodiments of the present application, in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in or transmitted from one computer-readable storage medium to another, for example, by wired (e.g., coaxial cable, optical fiber, digital Subscriber Line (DSL)), or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains one or more sets of available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. The semiconductor medium may be a solid state disk (solid state drive, SSD).

It should be understood that references herein to "at least one" mean one or more, and "a plurality" means two or more. In addition, in order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, the words "first", "second", and the like are used to distinguish the same item or similar items having substantially the same function and effect. It will be appreciated by those of skill in the art that the words "first," "second," and the like do not limit the amount and order of execution, and that the words "first," "second," and the like do not necessarily differ.

While the invention has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the invention. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A power detection circuit for an optical signal, the power detection circuit being configured to:

receiving a mixed optical signal, wherein the mixed optical signal is obtained by coherently mixing a detected optical signal and a local oscillation optical signal, the local oscillation optical signal comprises N optical carriers, the center frequencies of at least two optical carriers in the N optical carriers are different, and N is an integer greater than 1;

According to a target frequency interval, adjusting the center frequency of each optical carrier in the local oscillation optical signal, so that the center frequency of each optical carrier is changed in a corresponding frequency spectrum range, and traversing a plurality of frequency points to be detected in the corresponding frequency spectrum range, wherein the frequency spectrum ranges corresponding to the center frequencies of different optical carriers are different;

filtering the mixed optical signals, and determining the power of the tested optical signals at the center frequency of each optical carrier according to the filtered mixed optical signals;

the filtered mixed optical signal comprises components with the same frequency as the central frequency of each carrier wave in the local oscillation optical signal in the measured optical signal.

2. The power detection circuit according to claim 1, wherein the detected optical signal is a wavelength division multiplexing signal, the wavelength division multiplexing signal includes N service optical signals, the spectrum widths of the N service optical signals are the same, each service optical signal is a signal obtained by topping, and modulation frequencies of different service optical signals are different;

the power detection circuit is used for adjusting the center frequency of each optical carrier according to a target frequency interval, so that the center frequency of each optical carrier is changed in the frequency spectrum range of one service optical signal, and traversing a plurality of frequency points to be detected in the frequency spectrum range of the corresponding service optical signal;

Wherein the target frequency interval is smaller than the spectral width of the traffic light signal.

3. The power detection circuit according to claim 1, wherein the detected optical signal is a wavelength division multiplexed signal, the wavelength division multiplexed signal includes a plurality of service optical signals, spectrum widths of at least two of the plurality of service optical signals are different, each service optical signal includes at least one slice signal, each slice signal is a signal obtained by performing topping, modulation frequencies of different slice signals are different, and spectrum widths of different slice signals are the same, N is a total number of slice signals included in the wavelength division multiplexed signal;

the power detection circuit is used for adjusting the center frequency of each optical carrier according to a target frequency interval, so that the center frequency of each optical carrier is changed in the frequency spectrum range of one slice signal, and traversing a plurality of frequency points to be detected in the frequency spectrum range of the corresponding slice signal;

wherein the target frequency interval is smaller than a spectral width of the slice signal.

4. The power detection circuit of claim 1, wherein each of the optical carriers is a modulated signal, and the modulation frequencies of the different optical carriers are different;

The power detection circuit is used for adjusting the center frequency of each optical carrier according to a target frequency interval, and the target frequency interval is smaller than the frequency difference of the center frequencies of two adjacent optical carriers.

5. The power detection circuit of any one of claims 2 to 4, wherein the mixed optical signal comprises four components, the four components being a quadrature component of the first polarization component, an in-phase component of the first polarization component, a quadrature component of the second polarization component, and an in-phase component of the second polarization component, respectively;

the power detection circuit includes: a low pass filter, an operator, a comb filter, and a power detection sub-circuit;

the low-pass filter is used for respectively carrying out low-pass filtering on the four components;

the arithmetic unit is used for determining the power of the four components after low-pass filtering;

the comb filter is used for carrying out comb filtering on the power of the four components, wherein the number of pass bands of the comb filter is greater than or equal to N, and the center frequency of each pass band is equal to one modulation frequency;

the power detection sub-circuit is configured to determine power of the comb-filtered power of the four components at each modulation frequency, obtain top modulation power corresponding to each modulation frequency, and determine power of the measured optical signal at a center frequency of the optical carrier according to the top modulation power corresponding to each modulation frequency, intensity of the optical carrier corresponding to the modulation frequency, and top modulation depth corresponding to the modulation frequency.

6. The power detection circuit of claim 5, wherein an ith said modulation frequency corresponds to an ith said optical carrier, i being a positive integer no greater than N;

the detected optical signal is at the center frequency f of the ith optical carrier _Ci The power at this point satisfies:

wherein P is _Pi For the modulation top power corresponding to the ith modulation frequency, A _Ci For the intensity of the ith said optical carrier, a _i And (5) the modulation depth corresponding to the ith modulation frequency.

7. A system for power detection of an optical signal, the system comprising: a comb light source, a coherent receiver, and a power detection circuit;

the comb-shaped light source is used for transmitting local oscillation light signals, the local oscillation light signals comprise N light carriers, the center frequencies of at least two light carriers in the N light carriers are different, and N is an integer greater than 1;

the coherent receiver is used for carrying out coherent mixing on the detected optical signal and the local oscillation optical signal to obtain a mixed optical signal, and sending the mixed optical signal to the power detection circuit;

the power detection circuit is used for:

8. The system of claim 7, wherein the optical signal under test is a wavelength division multiplexed signal, the wavelength division multiplexed signal includes N service optical signals, the spectral widths of the N service optical signals are the same, each service optical signal is a signal obtained by topping, and modulation frequencies of different service optical signals are different;

9. The system of claim 7, wherein the optical signal under test is a wavelength division multiplexed signal, the wavelength division multiplexed signal comprises a plurality of service optical signals, the spectral widths of at least two of the plurality of service optical signals are different, each service optical signal comprises at least one slice signal, each slice signal is a signal obtained by roof-adjusting, the modulation frequencies of different slice signals are different, the spectral widths of different slice signals are the same, and N is the total number of slice signals included in the wavelength division multiplexed signal;

10. The system of claim 7, wherein each of the optical carriers is a modulated signal, and the modulation frequencies of the different optical carriers are different;

11. The system of any of claims 8 to 10, wherein the mixed optical signal comprises four components, the four components being a quadrature component of the first polarization component, an in-phase component of the first polarization component, a quadrature component of the second polarization component, and an in-phase component of the second polarization component, respectively;

12. The system of claim 11, wherein an ith said modulation frequency corresponds to an ith said optical carrier, i being a positive integer no greater than N;

13. A system according to any one of claims 7 to 10, wherein the comb-like light source comprises a frequency comb light source;

or the comb-shaped light source comprises a wave combiner and a plurality of frequency comb light sources with different wave bands, and the wave combiner is used for combining the light carriers emitted by the plurality of frequency comb light sources to obtain local oscillation light signals.

14. An optical communication system, the system comprising: the power detection system of an optical signal according to any one of claims 7 to 13, a first optical transceiver device, a second optical transceiver device, and at least one optical amplifier connected between the first optical transceiver device and the second optical transceiver device;

the coherent receiver in the power detection system is connected with a target device, and the coherent receiver is used for receiving the measured optical signal emitted by the target device, wherein the target device comprises at least one of the at least one optical amplifier, the first optical transceiver and the second optical transceiver.

15. A method for detecting power of an optical signal, the method comprising:

filtering the mixed optical signal; the filtered mixed optical signal comprises components with the same frequency as the central frequency of each carrier wave in the local oscillation optical signal in the detected optical signal;

determining the power of the tested optical signal at the center frequency of each optical carrier according to the filtered mixed optical signal;

and adjusting the center frequency of each optical carrier in the local oscillation optical signal according to the target frequency interval, so that the center frequency of each optical carrier is changed in a corresponding frequency spectrum range, and traversing a plurality of frequency points to be detected in the corresponding frequency spectrum range, wherein the frequency spectrum ranges corresponding to the center frequencies of different optical carriers are different.

16. The method of claim 15, wherein the optical signal under test is a wavelength division multiplexed signal, the wavelength division multiplexed signal includes N service optical signals, the spectral widths of the N service optical signals are the same, each service optical signal is a signal obtained by topping, and modulation frequencies of different service optical signals are different;

The adjusting the center frequency of each optical carrier in the local oscillator optical signal includes:

according to the target frequency interval, the center frequency of each optical carrier in the local oscillation optical signals is adjusted, so that the center frequency of each optical carrier is changed in the frequency spectrum range of one service optical signal, and a plurality of frequency points to be detected in the frequency spectrum range of the corresponding service optical signal are traversed;

17. The method of claim 15, wherein the optical signal under test is a wavelength division multiplexed signal, the wavelength division multiplexed signal includes a plurality of service optical signals, at least two of the plurality of service optical signals have different spectral widths, each service optical signal includes at least one slice signal, each slice signal is a signal obtained by performing roof-shifting, modulation frequencies of different slice signals are different, and the spectral widths of different slice signals are the same, and N is a total number of slice signals included in the wavelength division multiplexed signal;

According to the target frequency interval, adjusting the center frequency of each optical carrier wave, so that the center frequency of each optical carrier wave changes in the frequency spectrum range of one slice signal, and traversing a plurality of frequency points to be detected in the frequency spectrum range of the corresponding slice signal;

18. The method of claim 15, wherein each of the optical carriers is a modulated signal, and the modulation frequencies of the different optical carriers are different;

and adjusting the center frequency of each optical carrier according to a target frequency interval, wherein the target frequency interval is smaller than the frequency difference of the center frequencies of two adjacent optical carriers.

19. The method according to claim 16 or 17, wherein the mixed optical signal comprises four components, the four components being a quadrature component of the first polarization component, an in-phase component of the first polarization component, a quadrature component of the second polarization component, and an in-phase component of the second polarization component, respectively;

the filtering the mixed optical signal includes: respectively carrying out low-pass filtering on the four components;

Said determining the power of each of said traffic optical signals at the center frequency of one of said optical carriers from said filtered mixed optical signal comprises:

determining the power of the four components after low-pass filtering;

comb filtering the power of the four components by a comb filter, wherein the comb filter has a plurality of pass bands, and the center frequency of each pass band is equal to one modulation frequency;

determining the power of the comb-filtered power of the four components at each modulation frequency to obtain the top modulation power corresponding to each modulation frequency;

and determining the power of the measured optical signal at the center frequency of the optical carrier according to the top modulation power corresponding to each modulation frequency, the intensity of the optical carrier corresponding to the modulation frequency and the top modulation depth corresponding to the modulation frequency.

20. The method of claim 19, wherein the ith modulation frequency corresponds to the ith optical carrier, i being a positive integer no greater than N;

21. A chip comprising programmable logic circuits and/or program instructions for implementing the method of power detection of an optical signal according to any one of claims 15 to 20 when the chip is operating.