CN111108703B

CN111108703B - Method for detecting wavelength deviation and sink node

Info

Publication number: CN111108703B
Application number: CN201780095126.3A
Authority: CN
Inventors: 周谞; 邓宁; 马雅男; 董振华
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-09-30
Filing date: 2017-09-30
Publication date: 2021-04-20
Anticipated expiration: 2037-09-30
Also published as: CN111108703A; WO2019061434A1

Abstract

The application provides a method for detecting wavelength deviation and a sink node. The method comprises the following steps: acquiring a wavelength division multiplexing signal; acquiring information of a pilot signal in each optical signal according to the wavelength division multiplexing signal; wavelength deviation information of a transmitter transmitting each optical signal is determined based on information of the pilot signal in each optical signal. The method improves the detection efficiency of the wavelength deviation information and realizes the real-time monitoring of the wavelength deviation.

Description

Method for detecting wavelength deviation and sink node

Technical Field

The present application relates to communications technologies, and in particular, to a method for detecting a wavelength deviation and a sink node.

Background

With the popularization of high definition video services and the demand of 5G bearer networks, the traffic of metropolitan area networks is increasing explosively. Taking Dense Wavelength Division Multiplexing (DWDM) in a metropolitan area network as an example, the DWDM system has a fixed 50GHz channel spacing (the channel refers to a channel for transmitting an optical signal in the DWDM system), and the Wavelength deviation or frequency deviation of the optical signal sent by an optical transmitter in the system is between the magnitudes of [ -2.5GHz, +2.5GHz ].

In order to improve the wavelength stability when transmitting optical signals in a DWDM system, the prior art adopts a wavelength control device shown in fig. 1, and uses an adjustable band-pass filter in the device to filter out optical signals in different channels one by one, and then performs wavelength control adjustment operations on the optical signals of each channel one by one. The wavelength control adjustment operation specifically includes: the optical signal is transmitted to the broadband wavelength locking device, and the signal processor performs signal processing to obtain wavelength deviation information when each optical transmitter transmits the optical signal, and then the signal processor provides the obtained wavelength deviation information to the controller, and the controller adjusts the wavelength of the transmission light of the transmitter transmitting the optical signal according to the wavelength deviation information.

However, when the system has 80 or more channels, for example, when the system is an Ultra Dense Wavelength Division Multiplexing (UDWDM), the efficiency of determining the Wavelength deviation information of each optical transmitter using the above Wavelength control method is low, which affects the efficiency of adjusting the transmission light Wavelength of the optical transmitter, and the real-time performance of Wavelength monitoring of the system is poor.

Disclosure of Invention

The application provides a method for detecting wavelength deviation and a sink node, which are used for solving the technical problems that in the prior art, the detection efficiency of wavelength deviation information of an optical transmitter is low, and the real-time performance of wavelength monitoring of a system is poor.

In a first aspect, an embodiment of the present application provides a method for detecting a wavelength deviation, including:

acquiring a wavelength division multiplexing signal, wherein the wavelength division multiplexing signal comprises optical signals with at least two wavelengths, and the optical signals with different wavelengths carry pilot signals with different frequencies;

acquiring information of a pilot signal in each optical signal according to the wavelength division multiplexing signal; the information of the pilot signal includes a frequency of the pilot signal;

wavelength deviation information of a transmitter transmitting each optical signal is determined based on information of the pilot signal in each optical signal.

In the method provided by the first aspect, the sink node acquires the wavelength division multiplexing signal, and acquires the information of the pilot signal in each optical signal in the wavelength division multiplexing signal by combining the wavelength division multiplexing signal, and then determines the wavelength deviation information of each transmitter that transmits the optical signal according to the information of the pilot signal in each optical signal. In the method of this embodiment, the sink node determines the wavelength deviation information of the optical transmitter of each optical signal in parallel by synchronizing the information of the pilot signal of each optical signal, and it is not necessary to detect the wavelength deviation one by one and in sequence for each optical signal.

In one possible design, the information of the pilot signal includes: the information of the pilot signal further includes: amplitude information of the pilot signal.

The method provided by the possible design determines the wavelength deviation information of each transmitter sending the optical signal by using the amplitude information of the pilot signal and the frequency of the pilot signal, has simple determination mode, and further improves the detection efficiency of the wavelength deviation information

In a possible design, the obtaining information of the pilot signal in each optical signal according to the wavelength division multiplexing signal specifically includes:

and performing photoelectric conversion on the wavelength division multiplexing signals to obtain the information of the pilot signal in each optical signal in the wavelength division multiplexing signals.

In a possible design, the acquiring the wavelength division multiplexing signal specifically includes:

adopting pilot signals with different frequencies to modulate optical signals sent by different optical transmitters of a sink node to obtain at least two first optical signals; wherein different first optical signals carry pilot signals of different frequencies;

and performing wavelength division multiplexing operation on the at least two first optical signals to obtain first wavelength division multiplexing signals.

In a possible design, the photoelectrically converting the wavelength division multiplexing signals to obtain information of the pilot signal in each optical signal in the wavelength division multiplexing signals specifically includes:

performing power splitting operation on the first wavelength division multiplexing signal to obtain a first multiplexing signal and a second multiplexing signal; the first multiplexing signal and the second multiplexing signal both include at least two first optical signals, and the first optical signals included in the first multiplexing signal and the second multiplexing signal are the same;

performing optical-to-electrical conversion on the first multiplexed signal to obtain a first electrical signal corresponding to the first multiplexed signal, and performing a first operation on each first optical signal in the first multiplexed signal to obtain a first amplitude of a pilot signal in each first optical signal, where the first operation includes: determining the amplitude of the first electrical signal at the frequency of the pilot signal as a first amplitude of the pilot signal in the first optical signal according to the frequency of the pilot signal in the first optical signal;

transmitting the second multiplexed signal to a wavelength reference device for processing, performing photoelectric conversion on an optical signal output by the wavelength reference device to obtain a second electrical signal corresponding to the second multiplexed signal, and performing a second operation on each first optical signal in the second multiplexed signal to obtain a second amplitude of the pilot signal of each first optical signal, where the second operation includes: determining the amplitude of the second electrical signal at the frequency of the pilot signal to be a second amplitude of the pilot signal in the first optical signal according to the frequency of the pilot signal in the first optical signal;

for each first optical signal, performing the following operations: an amplitude variation value of the pilot signal in the first optical signal is determined based on the first amplitude and the second amplitude of the pilot signal in the first optical signal.

In a possible design, the determining wavelength deviation information of the optical transmitter that transmits each optical signal according to the information of the pilot signal in each optical signal specifically includes:

for each first optical signal, performing the following operations: and determining first wavelength deviation information of an optical transmitter sending the first optical signal in the sink node according to the amplitude change value of the pilot signal in the first optical signal and the direct ratio relationship between the amplitude change value of the pilot signal in the first optical signal and the power change value of the first optical signal.

In the method provided by each of the above possible designs, the aggregation node modulates the optical signals sent by different optical transmitters in the aggregation node by using pilot signals with different frequencies to obtain at least two first optical signals, performs wavelength division multiplexing on the at least two first optical signals to obtain first wavelength division multiplexing signals, performs power division multiplexing on the first optical signals based on the first wavelength division multiplexing signals to obtain first multiplexing signals and second multiplexing signals, performs different processing on the first multiplexing signals and the second multiplexing signals to obtain first amplitudes and second amplitudes of the pilot signals in each first optical signal, determines amplitude variation values of the pilot signals in each first optical signal according to the first amplitudes and the second amplitudes of the pilot signals in each first optical signal, and determines a proportional relationship between the amplitude variation values and the power variation values of the first optical signals according to the proportional relationship, first wavelength deviation information is determined for each of the optical transmitters in the aggregation node that transmits the first optical signal. In this embodiment, for the amplitude variation value of each first optical signal, the sink nodes are all obtained in parallel, and therefore, the sink nodes also obtain in parallel when determining the first wavelength deviation information of each first optical signal, so that this embodiment realizes parallel detection of wavelength deviation, improves detection efficiency of wavelength deviation information, and realizes real-time monitoring of wavelength deviation.

In one possible design, the method further includes:

and adjusting the sending light wavelength of the light transmitter sending the first optical signal in the sink node according to the first wavelength deviation information.

The method provided by the possible design adjusts the transmission optical wavelength of the optical transmitter that transmits the first optical signal in the sink node through the determined first wavelength deviation information, and the method has high adjustment precision and avoids interference between optical signals.

receiving a second wavelength division multiplexing signal formed by a second optical signal sent by at least one access node; the second optical signal is obtained by modulating an optical signal sent by an optical transmitter of the access node by the access node through a pilot signal of a corresponding frequency, and different second optical signals carry pilot signals of different frequencies.

performing photoelectric conversion on the second wavelength division multiplexing signal to obtain a modulation electrical signal corresponding to the second wavelength division multiplexing signal;

performing band-pass filtering on the modulated electrical signals to obtain electrical signals corresponding to each second optical signal, wherein the electrical signals corresponding to each second optical signal carry pilot signals in the second optical signals, and the electrical signals corresponding to each second optical signal comprise two direct-current component signals;

for each corresponding electrical signal of the second optical signal, performing the following operations: determining the frequency of a pilot signal in the second optical signal according to the frequency point difference of two direct current component signals in the electrical signal; the frequency point difference of the two direct current component signals is equal to 2 times of the frequency of the pilot signal.

for each second optical signal, performing the following operations:

determining a middle frequency point of two direct current component signals according to the frequency of a pilot signal in the second optical signal and the frequency points of the two direct current component signals on the electric signal corresponding to the second optical signal;

determining a difference value between the intermediate frequency point and the frequency of an optical signal sent by a local oscillation light source of the sink node;

and determining second wavelength deviation information of a transmitter in the access node, which transmits a second optical signal containing the pilot signal, according to the frequency and the difference of the pilot signal.

In the method provided by each possible design, the access node loads pilot signals with different frequencies on different uplink optical signals sent by the optical transmitter connected inside the access node, so as to obtain second optical signals with different wavelengths, forms second wavelength division multiplexing signals based on the second optical signals with different wavelengths, and sends the second wavelength division multiplexing signals to the aggregation node; the aggregation node performs photoelectric conversion on the second wavelength division multiplexing signal to obtain a modulated electrical signal corresponding to the second wavelength division multiplexing signal, performs band-pass filtering on the modulated electrical signal to obtain an electrical signal corresponding to each second optical signal, and then determines the frequency of a pilot signal in the second optical signal corresponding to each electrical signal based on the frequency point difference of two direct current component signals on each electrical signal, thereby determining the difference between the frequency of the pilot signal and the frequency of an optical signal sent by a local oscillation light source of the aggregation node, and determining second wavelength deviation information of a transmitter sending the second optical signal in the access node based on the difference. In this embodiment, under the condition that the access node has no wave lock, the coherent reception of the sink node may be used to detect the wavelength deviation or the frequency offset, and the access node receives the frequency offset information or the second wavelength deviation information and adjusts the wavelength of the transmitted light at the access node according to the information to realize the wavelength stability control; in addition, the sink node also obtains the second wavelength deviation information corresponding to each second optical signal in parallel, so that the embodiment realizes parallel detection of the wavelength deviation, improves the detection efficiency of the wavelength deviation information, and realizes real-time monitoring of the wavelength deviation.

In one possible design, the method further includes:

and sending the second wavelength deviation information to the access node so that the access node adjusts the sending light wavelength of the light transmitter which sends the second optical signal in the access node according to the second wavelength deviation information.

The method provided by the possible design enables the access node to detect the wavelength deviation or the frequency deviation through coherent reception of the sink node under the condition that the access node has no wave lock, receives the frequency deviation information or the second wavelength deviation information through the access node, adjusts the transmitting light wavelength at the access node according to the information to realize stable wavelength control, and reduces the detection cost of wavelength control.

In a second aspect, to implement the method for detecting a wavelength offset according to the first aspect, an embodiment of the present application provides an optical communication network element, which is the above-mentioned aggregation node, and the aggregation node has a function of implementing the method for detecting a wavelength offset. The functions can be realized by hardware, and the functions can also be realized by executing corresponding software by hardware. The hardware or software includes one or more modules corresponding to the above-described functions.

In a possible implementation manner of the second aspect, the sink node includes a plurality of functional modules or units, and is configured to implement any one of the methods for detecting a wavelength deviation in the first aspect.

In another possible implementation manner of the second aspect, the structure of the sink node may include a processor and a transceiver, and may further include: modulators, wavelength division multiplexers, optical splitters, photodetectors and filters, and wavelength reference devices such as wave locks. The processor is configured to support the sink node to perform corresponding functions in any one of the methods for detecting a wavelength deviation in the first aspect. The transceivers are used to support communication between the aggregation node and the access nodes, and may be, for example, optical transmitters and optical receivers. The aggregation node may further include a memory, coupled to the processor, that stores program instructions and data necessary for the aggregation node to perform the method for detecting wavelength deviation described above.

In a third aspect, an embodiment of the present application provides a computer storage medium for storing computer software instructions for a processor of the above sink node, which includes a program for executing the above first aspect.

In a fourth aspect, the present application provides a computer program product, which contains a computer program, and when the computer program is read and executed by a processor or other type of chip, the computer program can implement the method for detecting a wavelength deviation provided by the foregoing embodiments of the present application. The advantages and specific working principle achieved by the computer program product refer to the foregoing embodiments, and are not described in detail herein.

In a fifth aspect, an embodiment of the present application further provides a communication system, where the system includes a sink node and at least one access node; wherein the sink node is configured to perform the methods provided in the first aspect and the possible designs of the first aspect.

Compared with the prior art, according to the method for detecting wavelength deviation and the sink node provided by the application, the sink node acquires the wavelength division multiplexing signal, acquires the information of the pilot signal in each optical signal in the wavelength division multiplexing signal by combining the wavelength division multiplexing signal, and then determines the wavelength deviation information of each transmitter for transmitting the optical signal according to the information of the pilot signal in each optical signal. In the method of this embodiment, the sink node determines the wavelength deviation information of the optical transmitter of each optical signal in parallel by synchronizing the information of the pilot signal of each optical signal, and it is not necessary to detect the wavelength deviation one by one and in sequence for each optical signal.

Drawings

FIG. 1 is a schematic diagram of a wavelength control device in a DWDM system according to the prior art provided herein;

FIG. 2 is a schematic diagram of a network architecture provided herein;

FIG. 3 is a schematic flowchart illustrating a first embodiment of a method for detecting wavelength deviation according to the present disclosure;

fig. 4 is a schematic flowchart of a second embodiment of a method for detecting a wavelength deviation according to the present application;

fig. 5 is a first schematic structural diagram of a pilot-based wavelength locking device provided in the present application;

fig. 6 is a schematic structural diagram of a pilot-based wavelength locking device according to the present application;

fig. 7 is a schematic flowchart of a process in which a sink node obtains information of a pilot signal in each first optical signal in a first wavelength division multiplexing signal according to the present application;

FIG. 8 is a schematic structural diagram of a wavelength locking module provided herein;

FIG. 9 is a schematic diagram of the relationship between the power variation value and the frequency deviation provided in the present application;

fig. 10 is a schematic flowchart of a third embodiment of a method for detecting a wavelength deviation according to the present application;

fig. 11 is a schematic structural diagram of an access node provided in the present application;

FIG. 12 is a schematic diagram of an electrical signal corresponding to a second optical signal provided herein;

fig. 13 is a schematic structural diagram of a sink node according to a first embodiment of the present application;

fig. 14 is a schematic structural diagram of a sink node according to a second embodiment of the present application;

fig. 15 is a schematic structural diagram of a sink node according to a third embodiment of the present application;

fig. 16 is a schematic structural diagram of a sink node according to a fourth embodiment of the present disclosure.

Detailed Description

The method for detecting wavelength deviation provided by the application can be applied to the network architecture diagram shown in fig. 2. As shown in fig. 2, the network may include an aggregation node and at least one access node. The traffic or service of all the access nodes is converged to the sink node, and the sink node is connected with each access node through the optical wavelength. Each access node may contain 1 or more optical transceivers of different wavelengths. The sum of the number of optical wavelengths transmitted by all access nodes is equal to the number of optical wavelengths at the aggregation node. Optionally, the network architecture shown in fig. 1 may be a DWDM system, or may also be a UDWDM system, which is not limited in this embodiment.

It should be noted that the channel referred to in this embodiment refers to a channel for transmitting an optical signal transmitted by an optical transmitter. Different channels have different wavelengths or different frequencies, and optical signals with different wavelengths or different frequencies (the frequency of an optical signal is the speed of light/the wavelength of the optical signal) transmitted by an optical transmitter are transmitted in different channels.

In the current wavelength control method, generally, tunable bandpass filters in the wavelength control device shown in fig. 1 are used to filter out optical signals in different channels one by one, and then wavelength control adjustment operations are performed on the optical signals of each channel one by one. However, when the number of channels in the system is large, the efficiency of determining the wavelength deviation information of each optical signal by using the wavelength control method is low, so that the adjustment efficiency of the transmission optical wavelength of the optical transmitter is affected, and the real-time performance of wavelength monitoring of the system is poor. Therefore, the method for detecting wavelength deviation provided by the application aims to solve the technical problems in the prior art.

It should be understood that although the terms first, second, third, etc. may be used herein to describe certain features (assuming that the features are denoted by XXX), these terms are only used to distinguish one feature from another. For example, a first XXX may also be referred to as a second XXX, and similarly, a second XXX may also be referred to as a first XXX, without departing from the scope of embodiments of the present application.

The technical solution of the present application will be described in detail below with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.

Fig. 3 is a schematic flowchart of a first embodiment of a method for detecting a wavelength deviation according to the present application. Optionally, the execution subject of the embodiment of the method may be a sink node, and may also be other devices having the functions of the sink node in this application. The following embodiments are all described by taking the case where the execution subject is a sink node. The present embodiment relates to a specific process in which the sink node obtains information of a pilot signal in each optical signal in the wavelength division multiplexed signal by analyzing the wavelength division multiplexed signal, and determines wavelength deviation information of an optical transmitter (or a light source, a laser) that transmits the optical signal based on the information of the pilot signal. As shown in fig. 3, the method comprises the steps of:

s101: the aggregation node acquires a wavelength division multiplexing signal, wherein the wavelength division multiplexing signal comprises optical signals with at least two wavelengths, and the optical signals with different wavelengths carry pilot signals with different frequencies.

Specifically, in this embodiment, the wavelength division multiplexing signal obtained by the aggregation node may be a first wavelength division multiplexing signal obtained by the aggregation node performing wave combination processing on a first optical signal sent by an optical transmitter inside the aggregation node, may also be a second wavelength division multiplexing signal formed by a second optical signal sent by at least one access node received by the aggregation node, and may also be a wavelength division multiplexing signal obtained by the aggregation node in other manners.

S102: the sink node acquires information of a pilot signal in each optical signal according to the wavelength division multiplexing signal, wherein the information of the pilot signal comprises the frequency of the pilot signal.

Optionally, after receiving the wavelength division multiplexing signal, the aggregation node may perform analysis or photoelectric conversion on the wavelength division multiplexing signal, convert the wavelength division multiplexing signal in the optical domain into an electrical signal in the electrical domain, and then obtain information of the pilot signal of each optical signal in the wavelength division multiplexing signal based on operations such as analysis processing and filtering processing on the electrical signal.

Optionally, the information of the pilot signal may include a frequency of the pilot signal, and optionally, the information of the pilot signal may include a direct frequency value of the pilot signal, and may further include a frequency difference between the pilot signal and a signal with a known frequency. Optionally, the information of the pilot signal may include amplitude information of the pilot signal in addition to the frequency of the pilot signal. Optionally, the amplitude information of the pilot signal may be a direct amplitude value of the pilot signal, an amplitude variation value of the pilot signal in different processing manners, or an amplitude difference between the pilot signal and a signal with known amplitude and frequency.

S103: and the sink node determines the wavelength deviation information of the transmitter sending each optical signal according to the information of the pilot signal in each optical signal.

Specifically, after the sink node acquires the information of the pilot signal in each optical signal, the wavelength deviation information of each optical transmitter transmitting the optical signal may be determined by combining the relationship between the information of the pilot signal of each optical signal and the power of the optical transmitter transmitting the optical signal, and optionally, the frequency deviation information of each optical signal may also be determined. Or, the wavelength deviation information of each transmitter sending the optical signal may be determined by combining the relationship between the information of the pilot signal and the frequency or amplitude of the local oscillation light source in the sink node.

Optionally, the wavelength deviation information may be wavelength deviation information of a transmission optical signal of an optical transmitter in the aggregation node, or may also be wavelength deviation information of a transmission optical signal of an optical transmitter in the access node, where the wavelength deviation information is specifically of the optical transmitter of the aggregation node or of the optical transmitter of the access node, and is specifically determined by a mode of a wavelength division multiplexing signal obtained by the aggregation node. For example, when the wavelength division multiplexing signal acquired by the sink node is a first wavelength division multiplexing signal formed by first optical signals sent by a plurality of optical transmitters of the sink node, the wavelength deviation information determined by the sink node is the wavelength deviation information of the optical transmitters in the sink node; when the aggregation node acquires a second wavelength division multiplexing signal formed by a second optical signal sent by at least one access node, the wavelength deviation information determined by the aggregation node is the wavelength deviation information of the optical transmitter in the access node.

As can be seen from the above description, in this embodiment, when the sink node determines the wavelength deviation information of the optical signals, the wavelength deviation information of each optical signal is determined synchronously and in parallel based on the pilot signal of each optical signal, and is not determined one by one and in sequence for each optical signal.

In the method for detecting wavelength deviation provided by the application, the sink node acquires the wavelength division multiplexing signal, acquires the information of the pilot signal in each optical signal in the wavelength division multiplexing signal by combining the wavelength division multiplexing signal, and then determines the wavelength deviation information of each transmitter for transmitting the optical signal according to the information of the pilot signal in each optical signal. In the method of this embodiment, the sink node determines the wavelength deviation information of the optical transmitter of each optical signal in parallel by synchronizing the information of the pilot signal of each optical signal, and it is not necessary to detect the wavelength deviation one by one and in sequence for each optical signal.

Fig. 4 is a schematic flowchart of a second embodiment of a method for detecting a wavelength deviation according to the present application. Fig. 5 is a first structural diagram of the pilot-based wavelength locking device provided in the present application, and fig. 6 is a second structural diagram of the pilot-based wavelength locking device provided in the present application. The present embodiment relates to an optional implementation manner for the sink node to acquire wavelength deviation information of an optical signal sent by an optical transmitter of the sink node when a wavelength division multiplexing signal acquired by the sink node is a combined signal formed by the optical signal sent by the optical transmitter of the sink node. As shown in fig. 4, the method may include:

s201: the sink node modulates optical signals sent by different optical transmitters in the sink node by adopting pilot signals with different frequencies to obtain at least two first optical signals; wherein the different first optical signals carry pilot signals of different frequencies.

Referring to fig. 5, the apparatus includes at least two pilot generation modules (assumed to be respectively pt1.... cndot), at least one optical transmitter (assumed to be respectively semiconductor lasers ld1.. cndot), a modulator, a wavelength division multiplexer, a wavelength locking module, a pilot extraction and analysis module, and optionally, a controller (e.g., FPGA). Each optical transmitter is connected with a corresponding modulator, and is further connected with a wavelength division multiplexer (or a combiner), the wavelength division multiplexer is connected with a wavelength locking module, the wavelength locking module is connected with a pilot frequency extraction and analysis module through a signal processing module, and the pilot frequency extraction and analysis module is respectively connected to the ld1. The difference between fig. 6 and fig. 5 mainly lies in that an optical transmitter in fig. 6 is used as both a transmitting light source at a transmitting end and a local oscillator light source at a receiving end, that is, an Integrated Coherent Receiver (ICR) in fig. 6 is a device in which a sink node is used to receive an optical signal of an external node, and the ICR can receive both an optical signal of an external node and a part of an optical signal split by a semiconductor Laser (LD), and also can receive a part of the optical signal split by the Laser Diode (LD), and the part of the optical signal is received by the ICRThe two optical signals are mixed and output. CH in FIGS. 5 and 6₁……CH_nAnd a signal output channel for modulating a part of the optical signal output by the LD through the modulator.

With reference to the apparatuses shown in fig. 5 and fig. 6, the sink node generates a pilot signal by using a pilot generation module, which includes: a first pilot signal (frequency f1) generated by PT1, a second pilot signal (frequency f2) generated by PT2, an nth pilot signal (frequency fn) generated by PTn; optical transmitters in the aggregation node respectively transmit respective optical signals, and the frequency or wavelength of the optical signals transmitted by each optical transmitter is different. With reference to fig. 5 and 6, the sink node modulates the optical signal emitted by LD1 by using the first pilot signal generated by PT1 to obtain a first optical signal carrying the first pilot signal, and similarly, modulates the optical signal emitted by LDn by using the nth pilot signal generated by PTn to obtain a first optical signal carrying the nth pilot signal. Based on this, the sink node can obtain at least two first optical signals, and the first optical signals with different wavelengths carry pilot signals with different frequencies.

Optionally, in fig. 5 and fig. 6, one optical transmitter may send one optical signal, and may also send multiple optical signals, that is, one optical transmitter may send optical signals with multiple wavelengths (when one optical transmitter only sends one optical signal, the aggregation node includes at least two optical transmitters), and the aggregation node modulates different optical signals with pilot signals with different frequencies, so that the aggregation node may also obtain at least two first optical signals. That is, if one optical transmitter generates only one optical signal, it may be modulated with only one pilot signal, but the method is equally applicable to Ultra Dense Wavelength Division Multiplexing (UDWDM) systems in which wavelength channel spacing is less than 50GHz, in which each optical transmitter may generate a plurality of optical signals, and then a plurality of first optical signals may be generated in the optical domain by modulation of pilot signals of different frequencies.

S202: the aggregation node executes wavelength division multiplexing operation on the at least two first optical signals to obtain first wavelength division multiplexing signals.

Specifically, after the sink node obtains at least two first optical signals, optionally, a part of each first optical signal may be split by using devices such as an optical splitter inside the optical transmitter, and sent to the modulator for modulation, and the modulated optical signals are output through the wavelength channel, and another part of each first optical signal is sent to the wavelength division multiplexer for wavelength division multiplexing operation, so as to obtain a first wavelength division multiplexing signal.

It should be noted that S201 and S202 in this embodiment are optional implementations of S101 in the first embodiment.

S203: the aggregation node performs photoelectric conversion on the first wavelength division multiplexing signals to obtain information of the pilot signal in each first optical signal in the first wavelength division multiplexing signals.

Optionally, with continuing to combine with fig. 5 and fig. 6, the sink node may convert the first wavelength division multiplexing signal into an electrical signal, where the electrical signal includes at least two pilot signals, and based on the processing of the electrical signal, information of the pilot signal in each first optical signal may be obtained. Alternatively, the information of the pilot signal may be frequency of the pilot signal and amplitude information of the pilot signal. Optionally, as an optional implementation manner of S203, the S203 may include the steps shown in fig. 7:

s203 a: the aggregation node executes power splitting operation on the first wavelength division multiplexing signal to obtain a first multiplexing signal and a second multiplexing signal; the first multiplexed signal and the second multiplexed signal each include at least two first optical signals, and the first optical signals included in the first multiplexed signal and the second multiplexed signal are the same.

Optionally, the sink node may perform a power splitting operation on the first wavelength division multiplexing signal according to the power, and split the first wavelength division multiplexing signal to obtain a first multiplexing signal and a second multiplexing signal with different powers. It should be noted that the first optical signal included in the first multiplexing signal and the first optical signal included in the second multiplexing signal are the same, for example, the first multiplexing signal includes A, B, C, D four first optical signals, where a carries a first pilot signal with a frequency of f1, B carries a second pilot signal with a frequency of f2, C carries a third pilot signal with a frequency of f3, and D carries a fourth pilot signal with a frequency of f4, and then the second multiplexing signal also includes the above A, B, C, D four first optical signals. This power splitting operation may be performed by the wavelength locking module described above in fig. 5 and 6.

S203 b: performing photoelectric conversion on the first multiplexed signal to obtain a first electrical signal corresponding to the first multiplexed signal, and performing a first operation on each first optical signal in the first multiplexed signal to obtain a first amplitude of a pilot signal in each first optical signal, where the first operation includes: determining, from the frequencies of the pilot signals in the first optical signal, the amplitude of the first electrical signal at the frequencies of the pilot signals to be a first amplitude of the pilot signals in the first optical signal.

As shown in fig. 5 and fig. 6, the first multiplexed signal and the second multiplexed signal respectively enter different branches of the wavelength locking module for subsequent processing. For the first multiplexed signal, the sink node directly performs photoelectric conversion on the first multiplexed signal by using a photo detection diode (PD1) in the wavelength locking module to obtain a first electrical signal (one first electrical signal) corresponding to the first multiplexed signal. The aggregation node then performs a first operation on each first optical signal in the first multiplexed signal to obtain a first amplitude of the pilot signal in each first optical signal. Taking the first optical signal a as an example in S203a, the sink node determines the amplitude of the first electrical signal at f1 according to the frequency f1 of the pilot signal in the a signal, so as to obtain the first amplitude of the pilot signal in the a signal. Likewise, the first operation is also performed for the three first optical signals B, C, D in S203a, resulting in the first amplitude of the pilot signal in the B signal, the first amplitude of the pilot signal in the C signal, and the first amplitude of the pilot signal in the D signal.

S203 c: transmitting the second multiplexed signal to a wavelength reference device for processing, performing optical-to-electrical conversion on an optical signal output by the wavelength reference device to obtain a second electrical signal corresponding to the second multiplexed signal, and performing a second operation on each first optical signal in the second multiplexed signal to obtain a second amplitude of a pilot signal of each first optical signal, where the second operation includes: determining, from the frequency of the pilot signal in the first optical signal, the amplitude of the second electrical signal at the frequency of the pilot signal to be a second amplitude of the pilot signal in the first optical signal.

Specifically, for the second multiplexed signal, the sink node uses the wavelength reference device in the wavelength locking module to process the second multiplexed signal in advance, and transmits the optical signal output by the wavelength reference device to the PD2 in the wavelength locking module for photoelectric conversion, so as to obtain a second electrical signal (one second electrical signal) corresponding to the second multiplexed signal. Then, the aggregation node performs a second operation on each of the first optical signals in the second multiplexed signal to obtain a first amplitude of the pilot signal of each of the first optical signals in the second multiplexed signal. Continuing with the first optical signal a as illustrated in S203a, the sink node determines the amplitude of the second electrical signal at f1 according to the frequency f1 of the pilot signal in a, thereby obtaining a second amplitude of the pilot signal in the a signal. Likewise, the second operation is also performed for the three first optical signals B, C, D in S203a, resulting in the second amplitude of the pilot signal in the B signal, the second amplitude of the pilot signal in the C signal, and the second amplitude of the pilot signal in the D signal.

Optionally, the wavelength reference device may be a wave lock, optionally, the wave lock may be an etalon wave lock, and may also be another wave lock, which is not limited in this embodiment.

As described in S203b and S203c, the first multiplexed signal and the second multiplexed signal are respectively processed by two different paths in the wavelength locking module, so that the amplitudes of the pilot signals in the first optical signals with the same wavelength are different. For example, continuing with the example given in S203a, taking the a signal in the first multiplexed signal and the a signal in the second multiplexed signal as an example, the a signal in the first multiplexed signal and the a signal in the second multiplexed signal are the first optical signal with the same wavelength, the a signal is processed in S203b, the amplitude of the pilot signal (f1) in the obtained a signal is M1, the a signal is processed in S203c, and the amplitude of the pilot signal (f1) in the obtained a signal is M2.

S203 d: for each first optical signal, performing the following operations: and determining the amplitude variation value of the pilot signal in the first optical signal according to the first amplitude and the second amplitude of the pilot signal in the first optical signal.

Based on the above-mentioned processes of S203a to S203c, the sink node may obtain the first amplitude and the second amplitude of the pilot signal in each first optical signal, and then, for each first optical signal, the sink node may obtain the amplitude variation value of the pilot signal in each first optical signal according to the first amplitude and the second amplitude of the pilot signal in the first optical signal. Continuing with the first optical signal a as an example, the a signal is processed in S203b, the amplitude of the pilot signal (f1) in the a signal is M1, the a signal is processed in S203c, the amplitude of the pilot signal (f1) in the a signal is M2, and the sink node obtains the amplitude variation value of the pilot signal in the a signal as | M1-M2| based on M1 and M2. Likewise, the operation of S203d is also performed for the three first optical signals B, C, D in S203a, resulting in the amplitude variation value of the pilot signal in each first optical signal.

Alternatively, the process of S203d may be performed by the signal processing module shown in fig. 5 and 6 described above.

S204: and the sink node determines the wavelength deviation information of the optical transmitter sending each first optical signal according to the information of the pilot signal in each first optical signal in the first wavelength division multiplexing signal.

Alternatively, the process of S204 may be performed by the pilot extraction analysis module shown in fig. 5 and fig. 6. Optionally, because the first multiplexing signal and the second multiplexing signal enter the wavelength locking module to be processed in two different ways, after the same first optical signal in the first multiplexing signal and the second multiplexing signal enters the wavelength locking module, the power of the first optical signal output through the first way of the wavelength locking module is different from the power of the first optical signal output through the second way of the wavelength locking module. In addition, since the change of the optical power of the first optical signal may cause a corresponding change of the amplitude of the pilot signal carried by the first optical signal, that is, there is a direct relationship between the amplitude change value of the pilot signal in the first optical signal and the power change value of the first optical signal, the aggregation node may determine the optical power change value of each first optical signal according to the amplitude change value of the pilot signal in each first optical signal, and further obtain the first wavelength deviation information or the frequency deviation information of the optical transmitter that sends each first optical signal in the aggregation node based on the optical power change value of each first optical signal. It should be noted that, for the amplitude variation value of each first optical signal, the sink nodes are all obtained in parallel, and therefore, the sink nodes also obtain in parallel when determining the first wavelength deviation information of each first optical signal, so that the present embodiment improves the detection efficiency of the wavelength deviation information, and implements real-time monitoring of the wavelength deviation.

The following describes, by way of a simple example, a sink node determining first wavelength deviation information of an optical transmitter in the sink node that transmits each first optical signal according to an amplitude variation value of the pilot signal in each first optical signal and a direct relationship between the amplitude variation value of the pilot signal in each first optical signal and a power variation value of the first optical signal. Taking the signal a in the first multiplexed signal and the second multiplexed signal as an example, refer to the schematic diagram of the internal structure of the wavelength locking module shown in fig. 8.

As shown in fig. 8, the wavelength locking module includes two paths, which are a direct path (including only the photo detector diode PD1) and a non-direct path (including the etalon wave lock and the photo detector diode PD2), respectively, and when the a signal is processed by the direct path, the first amplitude of the pilot signal in the a signal is M1, and when the a signal is processed by the non-direct path, the second amplitude of the pilot signal in the a signal is M2, and when the modulation depth of the pilot signal is M, and the responsivities of the PD1 and the PD2 are R, the following relationships exist: m is k × P × M × R, where k is a constant and M is the amplitude of the pilot signal. Based on the formula, the optical power P1 of the A signal passing through the straight path and the optical power P2 of the A signal passing through the non-straight path can be respectively calculated, and then the power change value of | P1-P2| can be obtained.

Further, in conjunction with the relationship between the power variation value and the frequency deviation shown in fig. 9, the abscissa in fig. 9 is the frequency deviation and the ordinate is the power variation value. As can be seen from fig. 9, the result of | P1-P2| has a linear characteristic (as shown by a dotted line in fig. 9), and based on fig. 9 and the obtained values of | P1-P2|, the value of abscissa can be calculated, so as to obtain the frequency offset information of the a signal, and further based on the frequency offset information, the first wavelength deviation information when the optical transmitter transmits the a signal can be obtained.

Optionally, after obtaining the wavelength deviation information corresponding to each first optical signal, the sink node may adjust the transmission optical wavelength of the optical transmitter that transmits the first optical signal in the sink node according to each first wavelength deviation information. Optionally, the pilot extraction and analysis module in the aggregation node may transmit the wavelength deviation information corresponding to each first optical signal to a controller (e.g., an FPGA), and the controller adjusts the transmission optical wavelength of each optical transmitter that transmits the first optical signal in the aggregation node.

In the method for detecting wavelength deviation, a sink node modulates optical signals sent by different optical transmitters in the sink node by using pilot signals with different frequencies to obtain at least two first optical signals, performs wavelength division multiplexing on the at least two first optical signals to obtain first wavelength division multiplexing signals, performs power division multiplexing on the first wavelength division multiplexing signals to obtain first multiplexing signals and second multiplexing signals, performs different processing on the first multiplexing signals and the second multiplexing signals to obtain first amplitude and second amplitude of the pilot signal in each first optical signal, determines an amplitude variation value of the pilot signal in each first optical signal according to the first amplitude and the second amplitude of the pilot signal in each first optical signal, and determines a proportional relationship between the amplitude variation value and the power variation value of the first optical signal according to the proportional relationship between the amplitude variation value and the power variation value of the first optical signal, first wavelength deviation information is determined for each of the optical transmitters in the aggregation node that transmits the first optical signal. In this embodiment, for the amplitude variation value of each first optical signal, the sink nodes are all obtained in parallel, and therefore, the sink nodes also obtain in parallel when determining the first wavelength deviation information of each first optical signal, so that this embodiment realizes parallel detection of wavelength deviation, improves detection efficiency of wavelength deviation information, and realizes real-time monitoring of wavelength deviation.

The second embodiment mainly describes how the sink node detects the wavelength deviation information when the optical transmitter in the sink node transmits the optical signal, and the third embodiment mainly describes how the sink node detects the wavelength deviation information when the optical transmitter in the access node transmits the optical signal. In the access node, the frequency of the wave lock is practically equal to the spacing of the channel spacing, and when facing a UDWDM system with channel spacing smaller than 50GHz, for example, with wavelength channel spacing smaller than 12.5GHz, the wave lock with small frequency is difficult and costly to manufacture, and has a relatively large manufacturing error, thereby causing a large wavelength deviation error of the optical transmitter of the determined access node. Based on the problem, the present application provides a technical solution of the following embodiment, which cancels a wavelength reference device (e.g., a wave lock) in an access node to solve the problems of high difficulty and high cost of making a wave lock with a small frequency.

Fig. 10 is a schematic flowchart of a third embodiment of a method for detecting a wavelength deviation according to the present application. Fig. 11 is a schematic structural diagram of an access node provided in the present application. The present embodiment relates to an optional implementation manner for a sink node to obtain wavelength deviation information of an optical signal sent by an optical transmitter in an access node. As shown in fig. 10, the method may include:

s301: the sink node receives a second wavelength division multiplexing signal formed by a second optical signal sent by at least one access node; the second optical signal is obtained by the access node modulating an optical signal sent by an optical transmitter of the access node through a pilot signal of a corresponding frequency, and different second optical signals carry pilot signals of different frequencies.

Specifically, in this embodiment, one access node may transmit an optical signal with one or more optical wavelengths, and therefore, the second wavelength division multiplexing signal in this embodiment may be a signal obtained by combining uplink optical signals transmitted by at least two access nodes that transmit optical signals with only one optical wavelength, or may be a signal obtained by combining uplink optical signals transmitted by at least one access node that can transmit optical signals with multiple wavelengths.

Taking the second wavelength division multiplexing signal as an example of multiplexing a plurality of uplink optical signals transmitted by one access node, in conjunction with the access node shown in fig. 11, the access node includes at least two pilot generation modules (assumed to be PT1 ', PT 2.. till.. PTm', respectively), at least one optical transmitter (assumed to be LD1 ', the.. till.. LDm', respectively), and a wavelength division multiplexer. Wherein each optical transmitter is connected with a corresponding modulator, each modulator being connected to the wavelength division multiplexer. Different pilot frequency generation modules can generate pilot frequency signals of different frequencies, and different optical transmitters can transmit optical signals of different wavelengths. The method specifically comprises the following steps: the access node generates a pilot signal by using a pilot generation module, which respectively comprises: pilot signals 1 (frequency f1 ') generated by PT1 ', pilot signals 2 (frequency f2 ') generated by PT2, and pilot signals m (frequency fm ') generated by PTm '; the optical transmitters of the access nodes respectively transmit respective optical signals, and the frequency or wavelength of the optical signals transmitted by each optical transmitter is different. Referring to fig. 11, the sink node modulates the optical signal emitted by LD1 'by using the pilot signal 1 generated by PT 1', to obtain a second optical signal carrying the pilot signal 1. And the second optical signals are transmitted to the wavelength division multiplexer for corresponding processing to obtain second wavelength division multiplexing signals, and the second wavelength division multiplexing signals are sent to the aggregation node. The sink node may receive the second wavelength division multiplexing signal by using coherent reception through an internal coherent transceiver. Optionally, the transmitter in the coherent transceiver refers to an LD, a modulator, and a Data Signal Processing (DSP) module in a sink node (CR), and the receiver in the coherent transceiver is a local oscillator light source and an ICR in the CR.

S302: and the aggregation node performs photoelectric conversion on the second wavelength division multiplexing signals to obtain the information of the pilot signal in each second optical signal in the second wavelength division multiplexing signals.

Specifically, the sink node converts the received second wavelength division multiplexing signal into a modulated electrical signal, and based on the processing of the modulated electrical signal, information of the pilot signal in each second optical signal can be obtained. Alternatively, the information of the pilot signal may be a frequency of the pilot signal.

Optionally, as an optional implementation manner of S302, the sink node may perform photoelectric conversion on the second wavelength division multiplexing signal to obtain a modulated electrical signal corresponding to the second wavelength division multiplexing signal, and then perform band-pass filtering on the modulated electrical signal by the sink node to obtain an electrical signal corresponding to each second optical signal in the second wavelength division multiplexing signal. The electrical signal corresponding to each second optical signal carries the pilot signal in the second optical signal, and the electrical signal corresponding to each second optical signal includes two dc component signals, as shown in fig. 12. Therefore, for each electrical signal corresponding to the second optical signal, the following operations are performed: taking the second optical signal carrying the pilot signal 1 as an example, if the electrical signal corresponding to the second optical signal is R, the sink node determines the frequency of the pilot signal in the second optical signal corresponding to the R signal (i.e. the second optical signal carrying the pilot signal 1) according to the frequency point difference between two dc component signals in the R signal; the frequency point difference of the two direct current component signals is equal to 2 times of the frequency of the pilot signal in the second optical signal. Based on this relationship, the sink node can determine the frequency carrying the pilot signal 1. Similarly, the sink node can determine the frequency fm 'of the pilot signal in each second optical signal according to the frequency point difference between the two dc component signals on the electrical signal corresponding to each second optical signal (i.e., the frequency point difference 2 fm' between the two dc component signals is divided by 2).

After the sink node obtains the frequency of the pilot signal in each second optical signal, the following operations S303 to S305 are performed for each second optical signal, and the following processes of S303 to S305 are all described by taking one second optical signal as an example:

s303: and the sink node determines the intermediate frequency point of the two direct current component signals according to the frequency of the pilot signal in the second optical signal and the frequency points of the two direct current component signals on the electrical signal corresponding to the second optical signal.

Specifically, after the sink node determines the frequency fm' of the pilot signal in each second optical signal, the sink node can know which pilot signal corresponds to the two dc component signals on the electrical signal (before the sink node does not determine the frequency of the pilot signal, the sink node only knows the frequency points of the two dc component signals, and does not know which pilot signal of which frequency is included in the electrical signal where the dc component signal is located). Based on the corresponding relationship and the frequency points of the two direct current component signals on the electric signal, the intermediate frequency point of the direct current component signal can be determined, and the pilot signal of which frequency the intermediate frequency point corresponds to can be obtained. If the frequency points of two direct current component signals on the electrical signal are respectively F1 and F2 (wherein F2 is greater than F1), the middle frequency point of the two direct current component signals is equal to F1+ fm ', or F2-fm', or (F1+ F2)/2. That is, in the electrical signal corresponding to the second optical signal including the pilot signal m, the intermediate frequency point of the dc component signal is F1+ fm ', or F2-fm', or (F1+ F2)/2. The position of the intermediate frequency point can be seen in fig. 12.

S304: and the sink node determines the difference between the intermediate frequency point and the frequency of the optical signal sent by the local oscillation light source of the sink node.

S305: and the sink node determines second wavelength deviation information of a transmitter which sends a second optical signal containing the pilot signal in the access node according to the frequency of the pilot signal and the difference value.

Specifically, since the sink node itself can know the frequency of the optical signal sent by the local oscillator light source (LO) in the sink node, based on the frequency of the optical signal sent by the local oscillator light source and the intermediate frequency point, a difference Δ fm between the intermediate frequency point and the frequency of the optical signal sent by the local oscillator light source can be obtained, where the difference Δ fm is frequency offset information of an optical transmitter that sends the second optical signal including the pilot signal m in the access node. In combination with the frequency offset information and the relation between wavelength and frequency, second wavelength offset information of a transmitter in the access node transmitting a second optical signal comprising the pilot signal m can be determined.

After the sink node obtains the frequency offset information of each optical transmitter sending the second optical signal in the access node, optionally, the sink node may directly send the frequency offset information to the access node, or may send the second wavelength offset information to the access node. And after receiving the frequency offset information or the second wavelength deviation information, the access node correspondingly adjusts the wavelength of the uplink optical signal. Because the accuracy of the coherent receiver in the sink node for the pilot signal detection is in the MHz level and the slow-varying characteristic of the LD wavelength offset, the wavelength offset or frequency offset detection can be performed through the coherent reception of the sink node under the condition that the access node has no wave lock, and the access node receives the frequency offset information or the second wavelength offset information and adjusts the transmitted optical wavelength at the access node according to the information to realize the wavelength stable control.

As can be seen from the above description, in the method for detecting wavelength deviation provided by the present application, the access node loads pilot signals with different frequencies to different uplink optical signals sent by its own internal optical transmitter, so as to obtain second optical signals with different wavelengths, forms a second wavelength division multiplexing signal based on the second optical signals with different wavelengths, and sends the second wavelength division multiplexing signal to the aggregation node; the aggregation node performs photoelectric conversion on the second wavelength division multiplexing signal to obtain a modulated electrical signal corresponding to the second wavelength division multiplexing signal, performs band-pass filtering on the modulated electrical signal to obtain an electrical signal corresponding to each second optical signal, and then determines the frequency of a pilot signal in the second optical signal corresponding to each electrical signal based on the frequency point difference of two direct current component signals on each electrical signal, thereby determining the difference between the frequency of the pilot signal and the frequency of an optical signal sent by a local oscillation light source of the aggregation node, and determining second wavelength deviation information of a transmitter sending the second optical signal in the access node based on the difference. In this embodiment, under the condition that the access node has no wave lock, the coherent reception of the sink node may be used to detect the wavelength deviation or the frequency offset, and the access node receives the frequency offset information or the second wavelength deviation information and adjusts the wavelength of the transmitted light at the access node according to the information to realize the wavelength stability control; in addition, the sink node also obtains the second wavelength deviation information corresponding to each second optical signal in parallel, so that the embodiment realizes parallel detection of the wavelength deviation, improves the detection efficiency of the wavelength deviation information, and realizes real-time monitoring of the wavelength deviation.

Fig. 13 is a schematic structural diagram of a sink node according to a first embodiment of the present disclosure. As shown in fig. 13, the sink node may include: a first obtaining module 11, a second obtaining module 12 and a determining module 13.

Specifically, the first obtaining module 11 is configured to obtain a wavelength division multiplexing signal, where the wavelength division multiplexing signal includes optical signals with at least two wavelengths, and the optical signals with different wavelengths carry pilot signals with different frequencies;

a second obtaining module 12, configured to obtain information of a pilot signal in each optical signal according to the wavelength division multiplexing signal; the information of the pilot signal comprises a frequency of the pilot signal;

a determining module 13, configured to determine, according to information of the pilot signal in each optical signal, wavelength deviation information of a transmitter that transmits each optical signal.

The sink node provided by the present application may execute the above method embodiment, and the implementation principle and technical effect thereof are similar, which are not described herein again.

Optionally, the information of the pilot signal further includes: amplitude information of the pilot signal.

Further, the second obtaining module 12 is specifically configured to perform photoelectric conversion on the wavelength division multiplexing signals to obtain information of the pilot signal in each optical signal in the wavelength division multiplexing signals.

Fig. 14 is a schematic structural diagram of a sink node according to a second embodiment of the present disclosure. On the basis of the embodiment of the apparatus shown in fig. 13, further, the first obtaining module 11 may include: a modulation unit 111 and a wavelength division multiplexing unit 112.

Specifically, the modulation unit 111 is configured to modulate optical signals sent by different optical transmitters of the aggregation node with pilot signals of different frequencies to obtain at least two first optical signals; wherein different first optical signals carry pilot signals of different frequencies;

a wavelength division multiplexing unit 112, configured to perform a wavelength division multiplexing operation on the at least two first optical signals to obtain a first wavelength division multiplexing signal.

With continued reference to fig. 14, optionally, the second obtaining module 12 may include: a light splitting unit 121, a first photoelectric conversion unit 122, a second photoelectric conversion unit 123, and a signal processing unit 124.

Specifically, the optical splitting unit 121 is configured to perform a power splitting operation on the first wavelength division multiplexing signal to obtain a first multiplexing signal and a second multiplexing signal; the first multiplexed signal and the second multiplexed signal each include at least two first optical signals, and the first optical signals included in the first multiplexed signal and the second multiplexed signal are the same;

a first photoelectric conversion unit 122, configured to perform photoelectric conversion on the first multiplexed signal to obtain a first electrical signal corresponding to the first multiplexed signal, and perform a first operation on each first optical signal in the first multiplexed signal to obtain a first amplitude of a pilot signal in each first optical signal, where the first operation includes: determining, from the frequency of the pilot signal in the first optical signal, the amplitude of the first electrical signal at the frequency of the pilot signal to be a first amplitude of the pilot signal in the first optical signal;

a second photoelectric conversion unit 123, configured to obtain a second electrical signal corresponding to the second multiplexed signal by transmitting the second multiplexed signal to a wavelength reference device for processing, performing photoelectric conversion on an optical signal output by the wavelength reference device, and perform a second operation on each first optical signal in the second multiplexed signal to obtain a second amplitude of the pilot signal of each first optical signal, where the second operation includes: determining, from the frequency of the pilot signal in the first optical signal, the amplitude of the second electrical signal at the frequency of the pilot signal to be a second amplitude of the pilot signal in the first optical signal;

a signal processing unit 124, configured to perform the following operations for each first optical signal: and determining the amplitude variation value of the pilot signal in the first optical signal according to the first amplitude and the second amplitude of the pilot signal in the first optical signal.

Optionally, the determining module 13 is specifically configured to, for each first optical signal, perform the following operations: and determining first wavelength deviation information of an optical transmitter sending the first optical signal in the sink node according to the amplitude variation value of the pilot signal in the first optical signal and the direct proportion relationship between the amplitude variation value of the pilot signal in the first optical signal and the power variation value of the first optical signal.

Optionally, with continued reference to the apparatus shown in fig. 14, the sink node may further include: an adjustment module 14;

the adjusting module 14 is further configured to adjust a transmission light wavelength of a light transmitter in the sink node, where the light transmitter transmits the first optical signal, according to the first wavelength deviation information.

Alternatively, the modulation unit 111 in fig. 14 may be the PT and the LD in fig. 5, the wavelength division multiplexing unit 112 in fig. 14 may be the wavelength division multiplexer in fig. 5, the optical splitting unit 121 may be the wavelength locking module in fig. 5, the first photoelectric conversion unit 122 may be the PD1 in fig. 8, the second photoelectric conversion unit 123 may be the PD2 in fig. 8, the signal processing unit 124 may be the signal processing module in fig. 5, the determination module 13 may be the pilot extraction and analysis module in fig. 5, and the adjustment module 14 may be the FPGA in fig. 5.

Fig. 15 is a schematic structural diagram of a sink node according to a third embodiment of the present application. On the basis of the embodiment of the apparatus shown in fig. 13, further, the first obtaining module 11 is specifically configured to receive a second wavelength division multiplexing signal formed by a second optical signal sent by at least one access node; the second optical signal is obtained by the access node modulating an optical signal sent by an optical transmitter of the access node through a pilot signal of a corresponding frequency, and different second optical signals carry pilot signals of different frequencies. Alternatively, the first obtaining module 11 in fig. 15 may be the ICR in fig. 5. The second obtaining module 12 may include: a third photoelectric conversion unit 125, a filter unit 126, and a determination unit 127.

Specifically, the third photoelectric conversion unit 125 is configured to perform photoelectric conversion on the second wavelength division multiplexing signal to obtain a modulation electrical signal corresponding to the second wavelength division multiplexing signal; alternatively, the third photoelectric conversion unit 125 may also be a photodetector PD.

The filtering unit 126 is configured to perform band-pass filtering on the modulated electrical signal to obtain an electrical signal corresponding to each second optical signal, where the electrical signal corresponding to each second optical signal carries a pilot signal in the second optical signal, and the electrical signal corresponding to each second optical signal includes two dc component signals; alternatively, the filtering unit 126 may be a band pass filter.

A determining unit 127, configured to perform the following operations for the electrical signal corresponding to each second optical signal: determining the frequency of a pilot signal in the second optical signal according to the frequency point difference of two direct current component signals in the electrical signal; and the frequency point difference of the two direct current component signals is equal to 2 times of the frequency of the pilot signal.

Optionally, the determining module 13 is specifically configured to, for each second optical signal, perform the following operations:

determining a middle frequency point of the two direct current component signals according to the frequency of a pilot signal in the second optical signal and the frequency points of the two direct current component signals on the electrical signal corresponding to the second optical signal;

and determining second wavelength deviation information of a transmitter which transmits a second optical signal containing the pilot signal in the access node according to the frequency of the pilot signal and the difference value.

With continuing reference to fig. 15, optionally, the sink node further includes: a transmission module 15;

the sending module 15 is configured to send the second wavelength deviation information to the access node, so that the access node adjusts a sending optical wavelength of an optical transmitter that sends the second optical signal in the access node according to the second wavelength deviation information.

Fig. 16 is a schematic structural diagram of a sink node according to a fourth embodiment of the present disclosure. As shown in fig. 16, the aggregation node may include a receiver 31, a memory 32, a processor 33, at least one communication bus 34, a transmitter 35, a modulator 36, a wavelength division multiplexer 37, an optical splitter 38, a photodetector 39, and a filter 40, and a wavelength reference device 41, such as a wave lock. The communication bus 34 is used to realize communication connections between the elements. The memory 32 may comprise a high speed RAM memory, and may also include a non-volatile memory NVM, such as at least one disk memory, in which various programs may be stored for performing various processing functions and implementing the method steps of the present embodiment. In this embodiment, the transmitter 35 may be an optical transmitter in the aggregation node, the receiver 31 may also be an optical receiver in the aggregation node, the transmitter 35 and the receiver 31 may be integrated together to be implemented as a transceiver, and both the transmitter 35 and the receiver 31 may be coupled to the processor 33, which may implement the actions of receiving or transmitting under the instruction or control of the processor 33. The modulator 36, the wavelength division multiplexer 37, the optical splitter 38, the photodetector 39 and the filter 40 may be coupled to the processor 33 through the communication bus 34, and optionally, the modulator 36, the wavelength division multiplexer 37, the optical splitter 38, the photodetector 39 and the filter 40 may be coupled directly or indirectly to each other, and the specific functions of these devices may be referred to in the following embodiments.

In this embodiment, the processor 33 is configured to obtain a wavelength division multiplexing signal, where the wavelength division multiplexing signal includes optical signals with at least two wavelengths, obtain information of a pilot signal in each optical signal according to the wavelength division multiplexing signal, and determine wavelength deviation information of a transmitter that transmits each optical signal according to the information of the pilot signal in each optical signal; wherein, the optical signals with different wavelengths carry pilot signals with different frequencies; the information of the pilot signal comprises a frequency of the pilot signal;

Optionally, the photodetector 39 may perform photoelectric conversion on the wavelength division multiplexing signals under the control of the processor 33, so as to obtain information of the pilot signal in each optical signal in the wavelength division multiplexing signals.

In a possible implementation manner of the present application, the modulator 36 may be configured to modulate optical signals sent by different optical transmitters of a sink node with pilot signals of different frequencies to obtain at least two first optical signals; wherein different first optical signals carry pilot signals of different frequencies; a wavelength division multiplexer 37, configured to perform a wavelength division multiplexing operation on the at least two first optical signals to obtain a first wavelength division multiplexing signal.

Optionally, the optical splitter 38 is specifically configured to perform a power splitting operation on the first wavelength division multiplexing signal to obtain a first multiplexing signal and a second multiplexing signal; the first multiplexed signal and the second multiplexed signal each include at least two first optical signals, and the first optical signals included in the first multiplexed signal and the second multiplexed signal are the same;

the photodetector 39 is specifically configured to perform photoelectric conversion on the first multiplexed signal to obtain a first electrical signal corresponding to the first multiplexed signal, and perform a first operation on each first optical signal in the first multiplexed signal to obtain a first amplitude of a pilot signal in each first optical signal, where the first operation includes: determining, from the frequency of the pilot signal in the first optical signal, the amplitude of the first electrical signal at the frequency of the pilot signal to be a first amplitude of the pilot signal in the first optical signal; and a second operation, configured to transmit the second multiplexed signal to a wavelength reference device 41 for processing, perform optical-to-electrical conversion on the optical signal output by the wavelength reference device 41 to obtain a second electrical signal corresponding to the second multiplexed signal, and perform a second operation on each first optical signal in the second multiplexed signal to obtain a second amplitude of the pilot signal of each first optical signal, where the second operation includes: determining, from the frequency of the pilot signal in the first optical signal, the amplitude of the second electrical signal at the frequency of the pilot signal to be a second amplitude of the pilot signal in the first optical signal;

the processor 33 may perform the following for each first optical signal: and determining the amplitude variation value of the pilot signal in the first optical signal according to the first amplitude and the second amplitude of the pilot signal in the first optical signal.

Optionally, the processor 33 may further perform the following operations for each first optical signal: and determining first wavelength deviation information of an optical transmitter sending the first optical signal in the sink node according to the amplitude variation value of the pilot signal in the first optical signal and the direct proportion relationship between the amplitude variation value of the pilot signal in the first optical signal and the power variation value of the first optical signal.

Optionally, the processor 33 is further configured to adjust a transmission light wavelength of a light transmitter in the sink node, where the light transmitter transmits the first optical signal, according to the first wavelength deviation information.

In another possible implementation manner of the present application, the receiver 31 is configured to receive a second wavelength division multiplexing signal formed by a second optical signal sent by at least one access node; the second optical signal is obtained by the access node modulating an optical signal sent by an optical transmitter of the access node through a pilot signal of a corresponding frequency, and different second optical signals carry pilot signals of different frequencies.

The photodetector 39 may be further configured to perform photoelectric conversion on the second wavelength division multiplexing signal to obtain a modulation electrical signal corresponding to the second wavelength division multiplexing signal;

the filter 40 is configured to perform band-pass filtering on the modulated electrical signal to obtain an electrical signal corresponding to each second optical signal, where the electrical signal corresponding to each second optical signal carries a pilot signal in the second optical signal, and the electrical signal corresponding to each second optical signal includes two dc component signals;

the processor 33 may further perform the following operations for the electrical signal corresponding to each second optical signal: determining the frequency of a pilot signal in the second optical signal according to the frequency point difference of two direct current component signals in the electrical signal; and the frequency point difference of the two direct current component signals is equal to 2 times of the frequency of the pilot signal.

Further, the processor 33 may further perform the following operations for each second optical signal:

Optionally, the transmitter 35 is configured to send the second wavelength offset information to the access node, so that the access node adjusts a transmission optical wavelength of an optical transmitter in the access node, where the optical transmitter sends the second optical signal, according to the second wavelength offset information.

The present application also provides a computer-readable storage medium having stored therein instructions, which, when run on a computer, cause the computer to perform the method performed by the processor of the aggregation node in the above-described method embodiments.

Embodiments of the present application further provide a computer program product, which contains instructions that, when executed by a computer, cause the computer to perform the functions performed by the processor of the sink node in the above method.

All or part of the above embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented using a software program, 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. The procedures or functions described in accordance with the embodiments of the application, in whole or in part, result when the computer program instructions are loaded and executed on a computer. The computer may be a general purpose computer, a special purpose computer, a network of computers, or other programmable device. The computer instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium. For example, the computer instructions may be transmitted from one website site, computer, server, or data center to another website site, computer, server, or data center via wired (e.g., coaxial cable, digital subscriber line DSL), or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device, such as a server, a data center, etc., that incorporates one or more of the available media. The usable medium may be a magnetic medium such as a floppy disk, a hard disk, a magnetic tape, an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk SSD), among others.

Claims

1. A method of detecting wavelength deviations, comprising:

acquiring wavelength division multiplexing signals, wherein the wavelength division multiplexing signals comprise optical signals with at least two wavelengths, and the optical signals with different wavelengths carry pilot signals with different frequencies;

acquiring information of a pilot signal in each optical signal according to the wavelength division multiplexing signal; the information of the pilot signal comprises a frequency of the pilot signal;

determining wavelength deviation information of a transmitter which transmits each optical signal according to information of a pilot signal in each optical signal;

the information of the pilot signal further includes: amplitude information of the pilot signal;

the acquiring information of the pilot signal in each optical signal according to the wavelength division multiplexing signal specifically includes:

performing photoelectric conversion on the wavelength division multiplexing signals to obtain information of pilot signals in each optical signal in the wavelength division multiplexing signals;

the acquiring the wavelength division multiplexing signal specifically includes:

performing wavelength division multiplexing operation on the at least two first optical signals to obtain first wavelength division multiplexing signals;

performing photoelectric conversion on the wavelength division multiplexing signals to obtain information of a pilot signal in each optical signal in the wavelength division multiplexing signals, specifically including:

performing power splitting operation on the first wavelength division multiplexing signal to obtain a first multiplexing signal and a second multiplexing signal; the first multiplexed signal and the second multiplexed signal each include at least two first optical signals, and the first optical signals included in the first multiplexed signal and the second multiplexed signal are the same;

performing photoelectric conversion on the first multiplexed signal to obtain a first electrical signal corresponding to the first multiplexed signal, and performing a first operation on each first optical signal in the first multiplexed signal to obtain a first amplitude of a pilot signal in each first optical signal, where the first operation includes: determining, from the frequency of the pilot signal in the first optical signal, the amplitude of the first electrical signal at the frequency of the pilot signal to be a first amplitude of the pilot signal in the first optical signal;

transmitting the second multiplexed signal to a wavelength reference device for processing, performing optical-to-electrical conversion on an optical signal output by the wavelength reference device to obtain a second electrical signal corresponding to the second multiplexed signal, and performing a second operation on each first optical signal in the second multiplexed signal to obtain a second amplitude of a pilot signal of each first optical signal, where the second operation includes: determining, from the frequency of the pilot signal in the first optical signal, the amplitude of the second electrical signal at the frequency of the pilot signal to be a second amplitude of the pilot signal in the first optical signal;

for each first optical signal, performing the following operations: and determining the amplitude variation value of the pilot signal in the first optical signal according to the first amplitude and the second amplitude of the pilot signal in the first optical signal.

2. The method according to claim 1, wherein the determining wavelength deviation information of an optical transmitter transmitting each optical signal according to information of a pilot signal in each optical signal specifically comprises:

for each first optical signal, performing the following operations: and determining first wavelength deviation information of an optical transmitter sending the first optical signal in the sink node according to the amplitude variation value of the pilot signal in the first optical signal and the direct proportion relationship between the amplitude variation value of the pilot signal in the first optical signal and the power variation value of the first optical signal.

3. The method of claim 2, further comprising:

4. The method according to claim 1, wherein the obtaining the wdm signal specifically comprises:

receiving a second wavelength division multiplexing signal formed by a second optical signal sent by at least one access node; the second optical signal is obtained by the access node modulating an optical signal sent by an optical transmitter of the access node through a pilot signal of a corresponding frequency, and different second optical signals carry pilot signals of different frequencies.

5. The method according to claim 4, wherein performing optical-to-electrical conversion on the wavelength division multiplexing signals to obtain information of the pilot signal in each optical signal in the wavelength division multiplexing signals specifically comprises:

for each corresponding electrical signal of the second optical signal, performing the following operations: determining the frequency of a pilot signal in the second optical signal according to the frequency point difference of two direct current component signals in the electrical signal; and the frequency point difference of the two direct current component signals is equal to 2 times of the frequency of the pilot signal.

6. The method according to claim 5, wherein the determining wavelength deviation information of an optical transmitter transmitting each optical signal according to information of a pilot signal in each optical signal comprises:

for each second optical signal, performing the following operations:

7. The method of claim 6, further comprising:

and sending the second wavelength deviation information to the access node, so that the access node adjusts the sending optical wavelength of an optical transmitter sending the second optical signal in the access node according to the second wavelength deviation information.

8. A sink node, comprising:

the device comprises a first acquisition module, a second acquisition module and a processing module, wherein the first acquisition module is used for acquiring wavelength division multiplexing signals, the wavelength division multiplexing signals comprise optical signals with at least two wavelengths, and the optical signals with different wavelengths carry pilot signals with different frequencies;

the second acquisition module is used for acquiring the information of the pilot signal in each optical signal according to the wavelength division multiplexing signal; the information of the pilot signal comprises a frequency of the pilot signal;

a determining module, configured to determine, according to information of a pilot signal in each optical signal, wavelength deviation information of a transmitter that transmits each optical signal;

the second obtaining module is specifically configured to perform photoelectric conversion on the wavelength division multiplexing signals to obtain information of a pilot signal in each optical signal in the wavelength division multiplexing signals;

the first obtaining module includes:

the modulation unit is used for modulating optical signals sent by different optical transmitters of the sink node by adopting pilot signals with different frequencies to obtain at least two first optical signals; wherein different first optical signals carry pilot signals of different frequencies;

the wavelength division multiplexing unit is used for executing wavelength division multiplexing operation on the at least two first optical signals to obtain first wavelength division multiplexing signals;

the second obtaining module includes:

an optical splitting unit, configured to perform a power splitting operation on the first wavelength division multiplexing signal to obtain a first multiplexing signal and a second multiplexing signal; the first multiplexed signal and the second multiplexed signal each include at least two first optical signals, and the first optical signals included in the first multiplexed signal and the second multiplexed signal are the same;

a first photoelectric conversion unit, configured to perform photoelectric conversion on the first multiplexed signal to obtain a first electrical signal corresponding to the first multiplexed signal, and perform a first operation on each first optical signal in the first multiplexed signal to obtain a first amplitude of a pilot signal in each first optical signal, where the first operation includes: determining, from the frequency of the pilot signal in the first optical signal, the amplitude of the first electrical signal at the frequency of the pilot signal to be a first amplitude of the pilot signal in the first optical signal;

a second photoelectric conversion unit, configured to obtain a second electrical signal corresponding to the second multiplexed signal by transmitting the second multiplexed signal to a wavelength reference device for processing, performing photoelectric conversion on an optical signal output by the wavelength reference device, and perform a second operation on each first optical signal in the second multiplexed signal to obtain a second amplitude of the pilot signal of each first optical signal, where the second operation includes: determining, from the frequency of the pilot signal in the first optical signal, the amplitude of the second electrical signal at the frequency of the pilot signal to be a second amplitude of the pilot signal in the first optical signal;

a signal processing unit for performing the following operations for each first optical signal: and determining the amplitude variation value of the pilot signal in the first optical signal according to the first amplitude and the second amplitude of the pilot signal in the first optical signal.

9. The aggregation node according to claim 8, wherein the determining module is specifically configured to, for each first optical signal, perform the following operations: and determining first wavelength deviation information of an optical transmitter sending the first optical signal in the sink node according to the amplitude variation value of the pilot signal in the first optical signal and the direct proportion relationship between the amplitude variation value of the pilot signal in the first optical signal and the power variation value of the first optical signal.

10. The aggregation node of claim 9, wherein the aggregation node further comprises: an adjustment module;

the adjusting module is further configured to adjust a transmission light wavelength of a light transmitter that transmits the first optical signal in the sink node according to the first wavelength deviation information.

11. The aggregation node according to claim 8, wherein the first obtaining module is specifically configured to receive a second wavelength division multiplexing signal formed by a second optical signal sent by at least one access node; the second optical signal is obtained by the access node modulating an optical signal sent by an optical transmitter of the access node through a pilot signal of a corresponding frequency, and different second optical signals carry pilot signals of different frequencies.

12. The aggregation node of claim 11, wherein the second obtaining module comprises:

the third photoelectric conversion unit is used for performing photoelectric conversion on the second wavelength division multiplexing signal to obtain a modulation electrical signal corresponding to the second wavelength division multiplexing signal;

the filtering unit is used for performing band-pass filtering on the modulated electrical signals to obtain electrical signals corresponding to each second optical signal, wherein the electrical signals corresponding to each second optical signal carry pilot signals in the second optical signals, and the electrical signals corresponding to each second optical signal comprise two direct-current component signals;

a determining unit, configured to perform the following operations for the electrical signal corresponding to each second optical signal: determining the frequency of a pilot signal in the second optical signal according to the frequency point difference of two direct current component signals in the electrical signal; and the frequency point difference of the two direct current component signals is equal to 2 times of the frequency of the pilot signal.

13. The aggregation node according to claim 12, wherein the determining module is specifically configured to, for each second optical signal, perform the following operations:

14. The aggregation node of claim 13, wherein the aggregation node further comprises: a sending module;

the sending module is configured to send the second wavelength deviation information to the access node, so that the access node adjusts a sending optical wavelength of an optical transmitter that sends the second optical signal in the access node according to the second wavelength deviation information.