CN104052544B - Monitoring method and device for optical signal to noise ratio - Google Patents

Abstract

This application discloses a monitoring method for optical signal-to-noise ratio, which uses two kinds of filtering information to filter and interferometrically measure the optical signal and ASE noise at the transmitting end to obtain a correction value, and performs two kinds of filtering information on the monitored channel at the optical channel monitoring point. Filtering and delay interferometry, combined with the corresponding correction values obtained, obtain the absolute value of the power of the optical signal and ASE noise, and then monitor the OSNR. Based on the same inventive idea, this application also proposes an optical signal-to-noise ratio monitoring device, which has good resistance to spectral distortion damage of the measured signal, so that the OSNR of the measured signal can be accurately monitored online.

Description

A method and device for monitoring optical signal-to-noise ratio

technical field

The present application relates to the technical field of communications, and in particular to a method and device for monitoring an optical signal-to-noise ratio.

Background technique

Optical signal-to-noise ratio (OSNR) is one of the key performance parameters for monitoring and evaluating optical communication systems. It is of great value in line fault location, protection switching alarm, damage-aware routing, and system operation and maintenance optimization.

With the improvement of optical signal modulation rate and the application of reconfigurable optical add-drop multiplexer (ROADM) in dense wavelength division multiplexing (DWDM) optical network, based on out-of-band spontaneously emitted large emission (ASE) noise measurement and linear in- The traditional OSNR monitoring method of interpolation is no longer applicable.

However, polarization-assisted measurement OSNR monitoring methods using optical signals and ASE noise with different polarization characteristics, such as polarization zeroing method and polarization interferometry, for dual polarization multiplexing signals in coherent optical communication systems, such as dual polarization multiplexing orthogonal Both phase shift keying (DP-QPSK) and dual polarization multiplexed 16-symbol quadrature amplitude modulation (DP-16QAM) are difficult to apply.

The current OSNR test generally uses the spectrometer-based power integration method to measure the channel power and the off-band method to measure the in-band ASE noise power. However, this method is inefficient and needs to interrupt the service signal, so it cannot perform online real-time OSNR monitoring.

Contents of the invention

In view of this, the present application provides an optical signal-to-noise ratio monitoring method and device to solve the problem that the signal-to-noise ratio cannot be monitored online.

In order to solve the problems of the technologies described above, the technical solution of the present application is achieved in the following way:

A method for monitoring an optical signal-to-noise ratio (OSNR), the method comprising:

An optical signal with a percentage of A is coupled out from the monitoring point of the optical channel under test;

Filter the coupled optical signal with the first filtering information to obtain the first filtered signal, and then couple out two split optical signals with a percentage of B and C from the first filtered signal, and pass the split light with a percentage of B The signal is subjected to delay interference and measured to obtain the first optical power and the second optical power, and the third optical power is obtained by measuring the split optical signal with a percentage of C, and according to the stored first correction value and the second correction value, and the obtained first optical power The first optical power, the second optical power and the third optical power obtain the power value of the measured optical signal;

Filter the coupled optical signal with the second filtering information to obtain a second filtered signal, then couple out two split optical signals with a percentage of B and C from the second filtered signal, and pass the split optical signal with a percentage of B Perform delay interference and measure to obtain the fourth optical power and fifth optical power, measure the split optical signal with a percentage of C to obtain the sixth optical power, and obtain the fourth optical power according to the stored third correction value and fourth correction value power, the fifth optical power and the sixth optical power to obtain the ASE noise power value;

Among them, A, B, and C are all greater than 0 and less than 1, C is less than B, and the sum of C and B is 1; the first filtering information includes the center wavelength and channel bandwidth of the measured optical channel; the second filtering information includes: The central wavelength and OSNR reference bandwidth of the optical channel;

The OSNR value of the channel under test is obtained according to the obtained power value of the measured optical signal, the ASE noise power value, and the OSNR reference bandwidth.

An optical signal-to-noise ratio OSNR monitoring device, the device includes: a storage unit, a first coupling unit, a filtering unit, a second coupling unit, a delay interference unit, a first power measurement unit, a second power measurement unit, and a third power measurement unit units and computing units;

The storage unit is used to store a first correction value, a second correction value, a third correction value and a fourth correction value;

The first coupling unit is used to couple out an optical signal with a percentage of A from the monitoring point of the optical channel under test;

The filtering unit is configured to use first filtering information to filter the optical signal coupled out of the first coupling unit to obtain a first filtering signal; use second filtering information to filter the optical signal coupled out of the first coupling unit Filtering to obtain a second filtered signal; wherein, the first filtering information includes the center wavelength and channel bandwidth of the measured optical channel; the second filtering information includes the center wavelength and the OSNR reference bandwidth of the measured optical channel;

The second coupling unit is used to couple out two split optical signals with a percentage of B and C from the first filtered signal obtained by the filtering unit; couple out a percentage of the second filtered signal obtained by the filtering unit There are two split optical signals of B and C; among them, A, B, and C are all greater than 0 and less than 1, C is less than B, and the sum of C and B is 1;

The delay interference unit is configured to perform delay interference on the split optical signal with a percentage of B coupled by the second coupling unit from the first filtered signal; couple the second coupled unit from the second filtered signal Delay interference is performed on the split optical signal whose percentage is B;

The first power measurement unit is configured to measure the power of the signal processed by the delay interference unit for the signal coupled out of the first filtered signal to obtain the first optical power; for the delay interference unit for the second filter performing power measurement on the processed signal coupled out of the signal to obtain a fourth optical power;

The second power measurement unit is configured to measure the power of the signal-processed information coupled out of the first filtered signal by the interference delay unit to obtain a second optical power; performing power measurement on the signal-processed information coupled out of the signal to obtain the fifth optical power;

The third optical power is used to perform power measurement on the split optical signal with a percentage of C coupled out by the second coupling unit for the first filtered signal to obtain a third optical power; for the second coupling unit for the first filtered signal performing power measurement on the split optical signal with a percentage C coupled out of the second filtered signal to obtain the sixth optical power;

The calculation unit is configured to store the first correction value and the second correction value stored in the storage unit, the first optical power obtained by the first power measurement unit, and the second optical power obtained by the second power measurement unit. The optical power and the third optical power obtained by the third power measurement unit obtain the power value of the measured optical signal; according to the first correction value and the second correction value stored in the storage unit, and the first power measurement unit The fourth optical power obtained, the fifth optical power obtained by the second power measurement unit, and the sixth optical power obtained by the third power measurement unit obtain an ASE noise power value; according to the obtained power value of the measured optical signal , ASE noise power value, and OSNR reference bandwidth to obtain the OSNR value of the channel under test.

To sum up, this application uses two kinds of filtering information to filter and interferometry the transmitting end optical signal and ASE noise to obtain the correction value, and performs filtering and delay interferometry on the monitored channel at the optical channel monitoring point with two kinds of filtering information , combined with the corresponding correction value obtained, the absolute value of the power of the optical signal and ASE noise is obtained, and then the OSNR is monitored. It has good resistance to the spectral distortion damage of the measured signal, so that the OSNR of the measured signal can be accurately monitored online.

Description of drawings

Fig. 1 is the schematic flow chart of OSNR monitoring method in the embodiment of the present application;

Figure 2 is a simulation diagram of OSNR monitoring results;

FIG. 3 is a schematic structural diagram of a device applied to the above technology in a specific embodiment of the present application.

detailed description

In order to make the purpose, technical solutions and advantages of the present application clearer, the solutions described in the present application will be further described in detail below with reference to the accompanying drawings and examples.

In the embodiment of this application, an optical signal-to-noise ratio monitoring method is proposed. Two kinds of filtering information are used to filter and interferometrically measure the optical signal and ASE noise at the transmitting end to obtain a correction value. The information is filtered and delayed interferometry, combined with the corresponding correction value obtained, to obtain the absolute value of the power of the optical signal and ASE noise, and then monitor the OSNR, which has good resistance to the spectral distortion damage of the measured signal, so that it can be accurately monitored online Get the OSNR of the signal under test.

When the present application is specifically implemented, the device that realizes the OSNR monitoring of the present application is referred to as a monitoring device.

Before online OSNR monitoring in this application, the monitoring equipment needs to process the optical signal at the transmitter end and the ASE noise generated by the erbium-doped fiber amplifier (EDFA) respectively through the first filtering information and the second filtering information to obtain the first correction value in advance , the second correction value, the third correction value and the fourth correction value are stored and used for online OSNR monitoring, and these correction values are used to correct the monitoring value so as to obtain an accurate OSNR value of the measured channel.

Since this part of the processing is completed before online monitoring, and can be saved and used only once, resources during online monitoring will not be occupied, so monitoring efficiency can be improved.

Wherein, the first filtering information includes: the center wavelength and channel bandwidth of the measured optical channel, and the typical configuration of the channel bandwidth is 50 GHz, which can also be specifically configured according to actual applications.

The second filtering information includes: the center wavelength of the measured optical channel and the OSNR reference bandwidth. The OSNR reference bandwidth is typically 12.5 GHz, and can also be specifically configured according to the application.

The specific process of obtaining the first correction value, the second correction value, the third correction value and the fourth correction value in the embodiment of the present application is explained in detail below:

The monitoring device filters the optical signal at the transmitter end with the first filtering information, performs delay interference on the filtered optical signal, and obtains the phase length arm power and the cancellation arm power by measuring the delay interference result, and calculates the phase length arm power and The ratio of the canceling arm power is used as the first correction value and stored.

The monitoring equipment filters the ASE noise generated by the EDFA with the first filtering information, performs delay interference on the filtered noise, and obtains the phase long arm power and the phase cancellation arm power by measuring the delay interference result, and calculates the phase long arm power and phase The ratio of the canceling arm power is used as the second correction value and stored.

The monitoring device filters the optical signal at the transmitter end with the second filtering information, performs delay interference on the filtered optical signal, and obtains the phase length arm power and the cancellation arm power by measuring the delay interference result, and calculates the phase length arm power and The ratio of the canceling arm power is used as a third correction value and stored.

The monitoring equipment filters the ASE noise generated by the EDFA with the second filtering information, performs delay interference on the filtered noise, and obtains phase long arm power and phase cancellation arm power by measuring the delay interference result, and calculates the phase long arm power and phase The ratio of the canceling arm power is used as the fourth correction value and stored.

In the embodiment of the present application, the optical signal without noise is processed respectively to obtain the first correction value and the third correction value, and the ASE noise generated by the EDFA is respectively processed to obtain the second correction value and the fourth correction value. Using these The correction value monitors the OSNR value of the optical signal in the actual optical channel.

How to implement OSNR monitoring in specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Referring to FIG. 1 , FIG. 1 is a schematic flowchart of the OSNR monitoring method in the embodiment of the present application. The specific steps are:

Step 101, the monitoring device couples out an optical signal with a percentage A from the monitoring point of the optical channel under test.

The monitoring equipment uses an optical coupler to couple an optical signal with a percentage A from the optical channel for online OSNR monitoring. For the configuration of the percentage A, in the actual implementation, it can be configured according to the actual situation, so as to neither affect the actual communication nor make the monitoring value error too large, resulting in inaccurate monitoring as a principle. For example, A can be configured as 10%.

Step 102, the monitoring device uses the first filtering information to filter the coupled optical signal to obtain the first filtered signal, and then couples out two split optical signals with percentages B and C from the first filtered signal, and through the percentage Perform delay interference for the split optical signal of B and measure to obtain the first optical power and second optical power, measure the split optical signal with a percentage of C to obtain the third optical power, and according to the first correction value, the second correction value, The first optical power, the second optical power and the third optical power obtain the power value of the measured optical signal.

In this step, A, B, and C are all greater than 0 and less than 1, C is less than B, and the sum of C and B is 1. The percentage of the optical signal for power measurement after delayed interferometric processing is greater than that for direct power measurement. , during specific implementation, the values of B and C can be configured according to actual applications, for example, C is 10%, and B is 90%.

The monitoring device uses the first filtering information to filter the coupled optical signal through an adjustable optical bandpass filter, obtains the first filtered signal, and then uses an optical coupler to couple two split optical signals from the first filtered signal, Among them, after one optical signal passes through delayed interference, the first optical power and the second optical power are obtained by measuring the phase-long arm and the destructive arm respectively by two power meters; the other optical signal is measured by the power meter to obtain the third optical power. power.

The first optical power obtained by the monitoring device is the power of the constructive arm, and the second optical power obtained is the power of the destructive arm.

The monitoring device obtains the power value of the measured optical signal according to the first correction value, the second correction value, the first optical power, the second optical power and the third optical power, and the specific implementation is as follows:

Among them, P _{SIG_TEST} is the power value of the optical signal under test, α is the first correction value, β is the second correction value, P _{1_TEST} is the first optical power, P _{2_TEST} is the second optical power, P _{3_TEST} is the third optical power .

Step 103, the monitoring device filters the coupled optical signal with the second filtering information to obtain a second filtered signal, and then couples out two split optical signals with a percentage of B and C from the second filtered signal, and the passing percentage is The split optical signal of B is subjected to delay interference and measured to obtain the fourth optical power and the fifth optical power, and the split optical signal with a percentage of C is measured to obtain the sixth optical power, and according to the third correction value, the fourth correction value, the first The fourth optical power, the fifth optical power and the sixth optical power obtain the ASE noise power value.

In this step, A, B, and C are all greater than 0 and less than 1, C is less than B, and the sum of C and B is 1. After delayed interference processing, the percentage of the optical signal for power measurement is greater than that for direct power measurement. In actual implementation, the values of B and C can be configured according to the actual application. For example, C is 10 %, B is 90%.

The monitoring device uses the second filtering information to filter the coupled optical signal through an adjustable optical bandpass filter, obtains the second filtered signal, and then uses an optical coupler to couple two split optical signals from the second filtered signal, Among them, after one optical signal passes through delayed interference, the fourth optical power and the fifth optical power are obtained by measuring the phase-long arm and the destructive arm respectively by two power meters; the other optical signal is measured by a power meter to obtain the sixth optical power power.

The fourth optical power obtained by the monitoring device is the power of the constructive arm, and the fifth optical power obtained is the power of the destructive arm.

The monitoring equipment obtains the ASE noise power value according to the third correction value, the fourth correction value, the fourth optical power, the fifth optical power and the sixth optical power, specifically:

Among them, _{PASE_TEST} is the ASE noise power, α' is the third correction value, β' is the fourth correction value, P' _{1_TEST} is the fourth optical power, P' _{2_TEST} is the fifth optical power, P' _{3_TEST} is the sixth optical power power.

Step 102 and step 103 are executed in no particular order.

When performing delayed interference on the optical signal in step 102 and step 103, an adjustable optical delay line can be used to adjust the frequency response peak interval of the phase-long arm and the phase-destructive arm, and an optical phaser can be used to ensure the output of the phase-constructive arm and the phase-destructive arm of the delay interference The signal phase quadrature matching.

Step 104, the monitoring device obtains the OSNR value of the measured channel according to the obtained measured optical signal power value, ASE noise power value, and OSNR reference bandwidth.

In this step, the monitoring device obtains the OSNR value of the channel under test, specifically:

Among them, OSNR is the OSNR value of the channel under test, B _{ASE_TEST} is the OSNR reference bandwidth, and the OSNR bandwidth used in actual filtering.

The OSNR monitoring method provided in the embodiment of the present application has good resistance to the distortion damage of the measured optical signal spectrum, especially for high-speed optical signals multiplexed with dual polarization states.

In the following, the present application collects specific examples, and presents the effect that can be achieved by using the technical solution of the present application in the form of a simulation schematic diagram.

Referring to FIG. 2, FIG. 2 is a simulation diagram of OSNR monitoring results. In Fig. 2, OSNR monitoring is performed on 100Gb/s DP-QPSK signal and double subcarrier multiplexing 400Gb/s DP-16QAM signal. The abscissa is the actual value of OSNR, and the ordinate is the monitoring error. Figure 2 also includes the spectrum of the two signals at the transmitting end and the constellation diagram of the single polarization state and single subcarrier demodulation signal at the receiving end. The OSNR monitoring errors in the range of 4dB to 32dB are all less than 0.5dB, indicating that the embodiments of the present application can perform accurate OSNR monitoring on polarization multiplexed high-speed optical signals of different rates and modulation formats.

Based on the same inventive concept, the present application also proposes an optical signal-to-noise ratio monitoring device. Referring to FIG. 3 , FIG. 3 is a schematic structural diagram of a device applied to the above technology in a specific embodiment of the present application. The device includes: a storage unit 301, a first coupling unit 302, a filtering unit 303, a second coupling unit 304, a delay interference unit 305, a first power measurement unit 306, a second power measurement unit 307, a third power measurement unit 308 and computing unit 309 .

a storage unit 301, configured to store a first correction value, a second correction value, a third correction value, and a fourth correction value;

The first coupling unit 302 is configured to couple out an optical signal with a percentage of A from the monitoring point of the optical channel under test;

The filtering unit 303 is configured to use the first filtering information to filter the optical signal coupled out of the first coupling unit 302 to obtain a first filtering signal; use the second filtering information to filter the optical signal coupled out of the first coupling unit 302 to obtain a second Two filtering signals; wherein, the first filtering information includes the center wavelength and channel bandwidth of the measured optical channel; the second filtering information includes the center wavelength and OSNR reference bandwidth of the measured optical channel;

The second coupling unit 304 is used to couple out two split optical signals with percentages of B and C from the first filtered signal obtained by the filtering unit 303; C has two split optical signals; among them, A, B, and C are all greater than 0 and less than 1, C is less than B, and the sum of C and B is 1;

The delay interference unit 305 is configured to perform delay interference on the split optical signal with a percentage B coupled out by the second coupling unit 304 from the first filtered signal; Perform delayed interference for the split optical signal of B;

The first power measurement unit 306 is used to measure the power of the signal processed by the delay interference unit 305 for the signal coupled out of the first filtered signal to obtain the first optical power; performing power measurement on the signal after processing the output signal to obtain a fourth optical power;

The second power measurement unit 307 is configured to perform power measurement on the signal-processed information coupled out of the first filtered signal by the interference delay unit to obtain a second optical power; for the second filtered signal by the interference delay unit performing power measurement on the processed information coupled out of the signal to obtain the fifth optical power;

The third optical power is used to measure the power of the split optical signal with a percentage of C coupled out by the second coupling unit 304 for the first filtered signal to obtain the third optical power; for the second coupled unit 304 for the second filtered performing power measurement on the split optical signal with a percentage of signal coupling out of C to obtain the sixth optical power;

The calculation unit 309 is configured to store the first correction value and the second correction value stored in the storage unit 301, as well as the first optical power obtained by the first power measurement unit 306, the second optical power obtained by the second power measurement unit 307, and the first optical power obtained by the second power measurement unit 307. The third optical power obtained by the three power measurement unit 308 obtains the power value of the measured optical signal; according to the first correction value and the second correction value stored in the storage unit 301, and the fourth optical power obtained by the first power measurement unit 306, The fifth optical power obtained by the second power measurement unit 307 and the sixth optical power obtained by the third power measurement unit 308 obtain the ASE noise power value; according to the obtained power value of the measured optical signal, the ASE noise power value, and the OSNR reference Bandwidth to obtain the OSNR value of the channel under test.

Preferably,

The filtering unit 303 is further configured to filter the transmitter-end optical signal with the first filter information; filter the ASE noise generated by the EDFA with the first filter information; filter the transmitter-end optical signal with the second filter information; The second filtering information filters the ASE noise generated by the EDFA;

The delay interference unit 305 is further configured to perform delay interference on the optical signal filtered by the first filter information; perform delay interference on the noise filtered by the first filter information; delay the optical signal filtered by the second filter information Interfering; performing delayed interference on the noise filtered by the second filtering information;

The first power measurement unit 306 is further used to obtain the power of the long-term arm from the measurement of the optical signal filtered by the first filtering information to the delay interference result; the power of the long-term arm is obtained from the measurement of the noise of the first filter information to the measurement of the delay interference result; for The optical signal filtered by the second filtering information measures the delayed interference result to obtain the phase arm power; the noise filtered for the second filtering information measures the delayed interference result to obtain the phased arm power;

The second power measurement unit 307 is further used to obtain the power of the canceling arm from the measurement of the optical signal filtered by the first filtering information on the delay interference result; the measurement of the noise filtering on the first filtering information to the delay interference result to obtain the power of the canceling arm; for The optical signal filtered by the second filtering information measures the delay interference result to obtain the power of the canceling arm; the noise filtered for the second filtering information measures the delay interference result to obtain the canceling arm power;

The calculation unit 309 is further used to use the ratio of the power of the phase arm and the power of the destructive arm obtained for the optical signal filtered by the first filter information as the first correction value and trigger the storage unit 301 to store; for the noise filtered by the first filter information to obtain The ratio of the power of the phase arm and the power of the canceling arm is used as the second correction value and triggers the storage unit 301 to store; the ratio of the power of the phase arm and the power of the canceling arm obtained for the optical signal filtered by the second filtering information is used as the third correction value and trigger the storage unit 301 to store; the ratio of the power of the constructive arm to the power of the destructive arm obtained from the noise filtered by the second filtering information is used as the fourth correction value and trigger the storage unit 301 to store.

Preferably, it is characterized in that the delay interference unit 305 includes: an adjustable optical delay line unit 315 and an optical phase shift unit 325;

The adjustable optical delay line unit 315 is used to adjust the frequency response peak interval of the phase-long arm and the phase-destructive arm;

The optical phase shifting unit 325 is configured to ensure phase quadrature matching of signals output by the constructive arm and the destructive arm of the delay interference.

Preferably,

The filtering unit 303 is a tunable optical bandpass filter.

The units in the above embodiments can be integrated or deployed separately; they can be combined into one unit, or can be further split into multiple sub-units.

To sum up, this application uses two kinds of filtering information to filter and interferometry the transmitting end optical signal and ASE noise to obtain the correction value, and performs filtering and delay interferometry on the monitored channel at the optical channel monitoring point with two kinds of filtering information , combined with the obtained corresponding correction value, the absolute value of the power of the optical signal and ASE noise is obtained, and then the OSNR is monitored.

In the actual implementation of this application, the OSNR relative ratio monitoring is converted into data ratio monitoring, and the signal spectrum distortion damage can be regarded as common mode noise to be suppressed, thereby improving the resistance to nonlinear damage and cascade filter effect damage, thereby enabling The OSNR of the signal under test can be accurately monitored online.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included within the protection scope of this application.

Claims (5)

1. An OSNR monitoring method, comprising:

coupling out an optical signal with the percentage of A from a monitored point of a measured optical channel;

filtering the coupled optical signal by using first filtering information to obtain a first filtering signal, coupling two beam splitting optical signals with percentages of B and C from the first filtering signal, performing delay interference on the beam splitting optical signal with the percentage of B, measuring to obtain first optical power and second optical power, measuring the beam splitting optical signal with the percentage of C to obtain third optical power, and obtaining a power value of the measured optical signal according to the stored first correction value and second correction value, and the obtained first optical power, second optical power and third optical power;

filtering the coupled optical signal by second filtering information to obtain a second filtered signal, coupling two beam splitting optical signals with the percentages of B and C from the second filtered signal, performing delay interference on the beam splitting optical signal with the percentage of B, measuring to obtain fourth optical power and fifth optical power, measuring the beam splitting optical signal with the percentage of C to obtain sixth optical power, and obtaining a spontaneous amplified radiation ASE noise power value according to the stored third correction value and fourth correction value, and obtaining the fourth optical power, the fifth optical power and the sixth optical power;

a, B, C are all larger than 0 and smaller than 1, C is smaller than B, and the sum of C and B is 1; the first filtering information comprises the center wavelength and the channel bandwidth of the measured optical channel; the second filtering information includes: the center wavelength and OSNR reference bandwidth of the measured optical channel;

obtaining the OSNR value of the tested channel according to the obtained power value of the tested optical signal, the ASE noise power value and the OSNR reference bandwidth;

wherein,

the method for obtaining the stored first, second, third and fourth correction values comprises:

filtering an optical signal at the transmitter end by using first filtering information, performing delay interference on the filtered optical signal, measuring a delay interference result to obtain a constructive arm power and a destructive arm power, and calculating a ratio of the constructive arm power to the destructive arm power to serve as a first correction value and storing the first correction value;

filtering ASE noise generated by an EDFA by using first filtering information, performing delay interference on the filtered noise, measuring the delay interference result to obtain power of a constructive arm and power of a destructive arm, and calculating the ratio of the power of the constructive arm to the power of the destructive arm to serve as a second correction value and storing the second correction value;

filtering the optical signal at the transmitter end by using second filtering information, performing delay interference on the filtered optical signal, measuring the delay interference result to obtain constructive arm power and destructive arm power, and calculating the ratio of the constructive arm power to the destructive arm power to be used as a third correction value and storing the third correction value;

filtering ASE noise generated by the EDFA by using second filtering information, performing delay interference on the filtered noise, measuring the delay interference result to obtain power of a constructive arm and power of a destructive arm, and calculating the ratio of the power of the constructive arm to the power of the destructive arm to be used as a fourth correction value and storing the fourth correction value;

the obtaining of the power value of the measured optical signal according to the stored first correction value and second correction value, and the obtained first optical power, second optical power, and third optical power includes:

wherein, P_{SIG_TEST}α is the first correction value, β is the second correction value, P is the power value of the detected light signal_{1_TEST}Is a first optical power, P_{2_TEST}Is a second optical power, P_{3_TEST}A third optical power;

the obtaining of the ASE noise power value according to the stored third correction value and fourth correction value and the fourth optical power, the fifth optical power, and the sixth optical power includes:

wherein, P_{ASE_TEST}For ASE noise power, α ' is the third correction value, β ' is the fourth correction value, P '_{1_TEST}Is fourth optical power, P'_{2_TEST}Is fifth light power, P'_{3_TEST}Is a sixth optical power;

the obtaining of the OSNR value of the measured channel according to the obtained power value of the measured optical signal, the ASE noise power value, and the OSNR reference bandwidth includes:

wherein OSNR is the OSNR value of the channel to be measured, B_{ASE_TEST}Is the OSNR reference bandwidth.

2. The method of claim 1, when performing the delayed interference, comprising:

the tunable optical delay line is used to tune the peak interval of the frequency response of the constructive and destructive arms, and the optical phaser is used to ensure that the phase quadrature match of the signals output by the constructive and destructive arms of the delayed interference.

3. An OSNR monitoring apparatus, comprising: the device comprises a storage unit, a first coupling unit, a filtering unit, a second coupling unit, a delay interference unit, a first power measuring unit, a second power measuring unit, a third power measuring unit and a calculating unit;

the storage unit is used for storing a first correction value, a second correction value, a third correction value and a fourth correction value;

the first coupling unit is used for coupling the optical signal with the percentage of A from the monitoring point of the measured optical channel;

the filtering unit is configured to filter the optical signal coupled out by the first coupling unit with first filtering information to obtain a first filtering signal; filtering the optical signal coupled out by the first coupling unit by second filtering information to obtain a second filtering signal; the first filtering information comprises the center wavelength and the channel bandwidth of the measured optical channel; the second filtering information comprises the center wavelength of the measured optical channel and the OSNR reference bandwidth;

the second coupling unit is used for coupling two beam splitting optical signals with the percentages of B and C from the first filtering signal obtained by the filtering unit; coupling two beam splitting optical signals with percentages of B and C from a second filtering signal obtained by the filtering unit; a, B, C are all larger than 0 and smaller than 1, C is smaller than B, and the sum of C and B is 1;

the delay interference unit is used for performing delay interference on the beam splitting optical signal with the percentage B, which is coupled out from the first filtered signal by the second coupling unit; performing delay interference on the beam splitting optical signal with the percentage of B, which is coupled out from the second filtered signal by the second coupling unit;

the first power measurement unit is configured to perform power measurement on a signal, which is coupled out from the first filtered signal by the delay interference unit and is subjected to signal processing, so as to obtain a first optical power; performing power measurement on the signal which is coupled out from the second filtering signal and is processed by the delay interference unit to obtain fourth optical power;

the second power measurement unit is configured to perform power measurement on the information, which is obtained by the interference delay unit after signal processing and coupled out of the first filtered signal, so as to obtain a second optical power; performing power measurement on the information, which is coupled out from the second filtering signal and processed by the interference delay unit, so as to obtain fifth optical power;

the third power measurement unit is configured to perform power measurement on the beam splitting optical signal, which is coupled out by the second coupling unit according to the first filtered signal and has the percentage of C, so as to obtain a third optical power; performing power measurement on the beam splitting optical signal which is coupled out by the second coupling unit according to the second filtering signal and has the percentage of C to obtain sixth optical power;

the calculation unit is used for obtaining the power value of the measured optical signal according to the first correction value and the second correction value stored by the storage unit, and the first optical power obtained by the first power measurement unit, the second optical power obtained by the second power measurement unit and the third optical power obtained by the third power measurement unit; obtaining a spontaneous amplified radiation (ASE) noise power value according to the third correction value and the fourth correction value stored in the storage unit, and the fourth optical power obtained by the first power measurement unit, the fifth optical power obtained by the second power measurement unit and the sixth optical power obtained by the third power measurement unit; obtaining the OSNR value of the tested channel according to the obtained power value of the tested optical signal, the ASE noise power value and the OSNR reference bandwidth;

wherein,

the filtering unit is further configured to filter the transmitter-side optical signal with the first filtering information; filtering ASE noise generated by the erbium-doped fiber amplifier EDFA by using the first filtering information; filtering the optical signal at the transmitter end by using second filtering information; filtering the ASE noise generated by the EDFA by using second filtering information;

the delay interference unit is further configured to perform delay interference on the optical signal filtered by the first filtering information; performing delay interference on the noise filtered by the first filtering information; performing delay interference on the optical signal filtered by the second filtering information; performing delay interference on the noise filtered by the second filtering information;

the first power measurement unit is further used for measuring the delay interference result aiming at the optical signal filtered by the first filtering information to obtain the power of a constructive arm; measuring a noise pair delay interference result filtered by aiming at the first filtering information to obtain a constructive arm power; measuring the delay interference result aiming at the optical signal filtered by the second filtering information to obtain the power of a constructive arm; measuring a noise pair delay interference result filtered by aiming at the second filtering information to obtain a constructive arm power;

the second power measurement unit is further used for obtaining the destructive arm power by measuring the delayed interference result aiming at the optical signal filtered by the first filtering information; obtaining the power of a cancellation arm by measuring a noise pair delay interference result filtered by aiming at the first filtering information; measuring the delayed interference result aiming at the optical signal filtered by the second filtering information to obtain the power of a cancellation arm; obtaining the power of a cancellation arm by measuring a noise pair delay interference result filtered by aiming at the second filtering information;

the calculation unit is further configured to use a ratio of a constructive arm power and a destructive arm power obtained for the optical signal filtered by the first filtering information as a first correction value and trigger the storage unit to store the first correction value; the ratio of the power of a constructive arm and the power of a destructive arm obtained by aiming at the noise filtered by the first filtering information is used as a second correction value and triggers the storage unit to store the second correction value; the ratio of the power of a constructive arm and the power of a destructive arm obtained aiming at the optical signal filtered by the second filtering information is used as a third correction value and triggers the storage unit to store the third correction value; the ratio of the power of a constructive arm and the power of a destructive arm obtained by the noise filtered by the second filtering information is used as a fourth correction value and triggers the storage unit to store the fourth correction value;

wherein the calculating unit is specifically configured to obtain a power value of the measured optical signal according to the first correction value and the second correction value stored in the storage unit, and the first optical power obtained by the first power measuring unit, the second optical power obtained by the second power measuring unit, and the third optical power obtained by the third power measuring unit,wherein, P_{SIG_TEST}α is the first correction value, β is the second correction value, P is the power value of the detected light signal_{1_TEST}Is a first optical power, P_{2_TEST}Is a second optical power, P_{3_TEST}A third optical power; when the spontaneous amplified radiation ASE noise power value is obtained according to the third correction value and the fourth correction value stored in the storage unit, and the fourth optical power obtained by the first power measurement unit, the fifth optical power obtained by the second power measurement unit and the sixth optical power obtained by the third power measurement unit,wherein, P_{ASE_TEST}For ASE noise power, α ' is the third correction value, β ' is the fourth correction value, P '_{1_TEST}Is fourth optical power, P'_{2_TEST}Is fifth light power, P'_{3_TEST}Is a sixth optical power; when the OSNR value of the tested channel is obtained according to the obtained power value of the tested optical signal, the ASE noise power value and the OSNR reference bandwidth,wherein OSNR is the OSNR value of the channel to be measured, B_{ASE_TEST}Is the OSNR reference bandwidth.

4. The apparatus of claim 3, wherein the delay interference unit comprises: the tunable optical delay line unit and the optical phase shifting unit;

the adjustable optical delay line unit is used for adjusting the frequency response peak value interval of the constructive arm and the destructive arm;

and the optical phase shifting unit is used for ensuring that the phases of signals output by the constructive arm and the destructive arm of the delay interference are in quadrature matching.

5. The apparatus according to claim 3 or 4,

the filtering unit is a tunable optical bandpass filter.