WO2016180080A1 - Determination method and device for optical signal-noise ratio (osnr) - Google Patents

Abstract

The present invention provides a determination method and device for an optical signal-noise ratio (OSNR). The method comprises: determining a noise power correction factor k, and correcting, according to the determined k, noise power P_N of a detected optical signal; and determining, according to the corrected noise power P_ASE, an optical signal-noise ratio (OSNR). The present invention solves the problem of great error of a detected optical signal-noise ratio in the related art, and further realizes an effect of reducing the error of the detected optical signal-noise ratio.

Description

Method and device for determining optical signal to noise ratio OSNR Technical field

The present invention relates to the field of communications, and in particular to a method and apparatus for determining an optical signal to noise ratio OSNR.

Background technique

Optical Signal-Noise Ratio (OSNR) is one of the most important performance parameters of the physical layer of optical signals. In the optical transmission link cascaded by multi-stage optical amplifiers, the final error of OSNR and data signal reception The code rate is directly related. Through OSNR monitoring, it is possible to trace the root cause of system performance degradation, perform early warning of early damage and failure, and initiate important functions such as compensation equalization mechanism. The traditional OSNR measurement method is a linear interpolation method, which measures the Amplified Spontaneous Emission (ASE) noise power at the interval of a Wavelength Division Multiplexing (WDM) channel, and then uses both sides of the channel. The linear interpolation of the ASE noise power is used as the ASE noise power in the WDM channel band to measure the OSNR value. The measurement of the WDM channel OSNR is typically performed using a spectral analyzer with a 0.1 nm resolution bandwidth. In a point-to-point optical transmission link that only includes a cascaded optical amplifier, the above method can accurately estimate the OSNR level. However, in an optical network including a Reconfigurable Optical Add-Drop Multiplexer (ROADM) and an Optical Cross-Connect (OXC), and a Nyquist-WDM system, The above-mentioned out-of-band OSNR measurement method will no longer be applicable, and in-band optical signal-to-noise ratio monitoring must be performed.

There are two main types of in-band OSNR monitoring methods: data-assisted method and no-data-assisted method. Data-assisted methods require modifications to the optical transmitter and reduce spectrum utilization efficiency. Non-data-assisted methods include polarization zeroing, delay interferometry, beat frequency noise method, error vector magnitude method, and moment method. Among these methods, the error vector magnitude method and the moment method are relatively simple to implement, and are suitable for linear optical communication systems, but the monitoring error is relatively large.

The error vector amplitude method monitors the optical signal-to-noise ratio by measuring the error vector magnitude of the constellation of the received optical signal and the reference constellation. It is necessary to first perform frequency offset and phase noise estimation on the correlated optical received signal, and the monitoring system is complex, and the modulation format is Related. The moment method assumes that the ASE noise and optical signal of the optical amplifier are statistically independent and have no interaction. By calculating the second and fourth moments of the coherent optical demodulation signal, the optical signal to noise ratio is monitored and also related to the modulation format. Both the error vector magnitude method and the moment method assume that the signal and noise do not interact, and the calculated noise is used as the ASE noise of the amplifier, thus overestimating the ASE noise, resulting in a large error in the monitored optical signal-to-noise ratio.

In view of the problem that the detected optical signal-to-noise ratio error is large in the related art, an effective solution has not been proposed yet.

Summary of the invention

The invention provides a method and a device for determining an optical signal-to-noise ratio OSNR, so as to at least solve the problem that the detected optical signal-to-noise ratio error is large in the related art.

According to an aspect of the present invention, a method for determining an optical signal-to-noise ratio OSNR includes: determining a noise power correction factor k; correcting a noise power P _{N of the} detected optical signal according to the determined k; according to the corrected noise The power P _ASE determines the optical signal to noise ratio OSNR.

其中，P_sig＝P_total-P_N。Optionally, determining the noise power correction factor k includes: determining a total power P _{total of} the optical signal and a noise power P _{N of} the optical signal; determining the k according to the determined P _total and the P _N , Including, determining the k by the following formula:

Where P _sig =P _total -P _N .

Optionally, the P _total is determined by the following formula: P _total = E{|y| ² }, where E{} is a second-order moment operation, y={y _n }, y _n is for the optical signal The value of the optical signal at the nth taking point after the predetermined processing, y _n =Re(y _n )+i*Im(y _n ), Re(y _n ) is the real part, Im(y _n ) is the virtual , n is a positive integer; and/or, the P _N is determined by the following formula: P _N =(std{|Re(y)|}) ² +(std{|Im(y)|}) ² , wherein , y={y _n }, y _n is the value of the optical signal at the nth point after the predetermined processing of the optical signal, y _n =Re(y _n )+i*Im(y _n ), Re(y _n ) is the real part, Im(y _n ) is the imaginary part, std{|Re(y)|} is the root mean square of the absolute value of the real part, and std{|Im(y)|} is the imaginary part. a root mean square of values, n is a positive integer; wherein the predetermined process comprises: performing coherent demodulation on the optical signal to obtain a real part and an imaginary part of the coherently demodulated optical signal; The real part performs transimpedance amplification and analog-to-digital conversion processing, performs transimpedance amplification and analog-to-digital conversion processing on the imaginary part of the optical signal; and real and virtual after trans-resistance amplification and analog-to-digital conversion processing Digital signal processing are performed; after the digital signal processing of the real part and the imaginary part for dispersion equalization.

Optionally, correcting the noise power P _{N of the} detected optical signal according to the determined k comprises: correcting the P _{N by} :

通过如下公式确定所述OSNR：

其中，R_B为码元速率，B_r为测量光信噪比的参考带宽。Optionally, determining the optical signal to noise ratio OSNR according to the modified noise power P _ASE includes: determining a signal carrier-to-noise ratio CNR by using the following formula:

The OSNR is determined by the following formula:

Where R _B is the symbol rate and B _r is the reference bandwidth for measuring the optical signal to noise ratio.

According to another aspect of the present invention, there is provided an apparatus for determining an optical signal-to-noise ratio OSNR, comprising: a first determining module configured to determine a noise power correction factor k; and a second determining module configured to be corrected according to the determined k The noise power P _{N of the} detected optical signal; a third determining module configured to determine the optical signal to noise ratio OSNR based on the corrected noise power P _ASE .

其中，P_sig＝P_total-P_N。Optionally, the first determining module includes: a first determining unit, configured to determine a total power P _{total of} the optical signal and a noise power P _{N of} the optical signal; and a second determining unit configured to determine according to the determining The P _total and the P _N determine the k, including determining the k by the following formula:

Where P _sig =P _total -P _N .

Optionally, the P _total is determined by the following formula: P _total = E{|y| ² }, where E{} is a second-order moment operation, y={y _n }, y _n is for the optical signal The value of the optical signal at the nth taking point after the predetermined processing, y _n =Re(y _n )+i*Im(y _n ), Re(y _n ) is the real part, Im(y _n ) is the virtual , n is a positive integer; and/or, the P _N is determined by the following formula: P _N =(std{|Re(y)|}) ² +(std{|Im(y)|}) ² , wherein , y={y _n }, y _n is the value of the optical signal at the nth point after the predetermined processing of the optical signal, y _n =Re(y _n )+i*Im(y _n ), Re(y _n ) is the real part, Im(y _n ) is the imaginary part, std{|Re(y)|} is the root mean square of the absolute value of the real part, and std{|Im(y)|} is the imaginary part. a root mean square of values, n is a positive integer; wherein the predetermined process comprises: performing coherent demodulation on the optical signal to obtain a real part and an imaginary part of the coherently demodulated optical signal; The real part performs transimpedance amplification and analog-to-digital conversion processing, performs transimpedance amplification and analog-to-digital conversion processing on the imaginary part of the optical signal; and real and virtual after trans-resistance amplification and analog-to-digital conversion processing Digital signal processing are performed; after the digital signal processing of the real part and the imaginary part for dispersion equalization.

Optionally, the second determining module includes: modifying the _{PN by} :

通过如下公式确定所述OSNR：

其中，R_B为码元速率，B_r为测量光信噪比的参考带宽。通过本发明，采用确定噪声功率修正因子k；根据确定的k修正被检测的光信号的噪声功率P_N；根据修正后的噪声功率P_ASE确定光信噪比OSNR。利用修正后的噪声功率计算光信噪比能够提高计算的精度，减小计算误差，从而解决了相关技术中存在的检测的光信噪比误差大的问题，进而达到了减小检测的光信噪比误差的效果。 Optionally, the third determining module includes: determining a signal carrier-to-noise ratio CNR by using the following formula:

The OSNR is determined by the following formula:

Where R _B is the symbol rate and B _r is the reference bandwidth for measuring the optical signal to noise ratio. With the present invention, the noise power correction factor k is determined; the noise power P _{N of the} detected optical signal is corrected according to the determined k; and the optical signal to noise ratio OSNR is determined based on the corrected noise power P _ASE . Calculating the optical signal-to-noise ratio by using the corrected noise power can improve the calculation accuracy and reduce the calculation error, thereby solving the problem that the detected optical signal-to-noise ratio error is large in the related art, thereby achieving the reduction of the detected optical signal. The effect of the noise ratio error.

DRAWINGS

The drawings described herein are intended to provide a further understanding of the invention, and are intended to be a part of the invention. In the drawing:

1 is a flow chart of a method of determining an optical signal to noise ratio OSNR according to an embodiment of the present invention;

2 is a block diagram showing the structure of an apparatus for determining an optical signal-to-noise ratio OSNR according to an embodiment of the present invention;

3 is a block diagram showing the structure of a first determining module 22 in an apparatus for determining an optical signal-to-noise ratio OSNR according to an embodiment of the present invention;

4 is an overall flow chart of in-band OSNR monitoring of an optical communication system based on second-order moment and noise correction, in accordance with an embodiment of the present invention;

5 is a diagram of an in-band OSNR monitoring apparatus for an optical communication system based on second-order moment and noise correction, in accordance with an embodiment of the present invention;

6 is a schematic diagram of total signal power after coherent reception of a 30.2 GB QPSK optical signal with a fiber input power of -3.0, +0.0, and +2.0 dBm, respectively, according to an embodiment of the present invention;

7 is a schematic diagram of total noise power after coherent reception of a 30.2 GB QPSK optical signal with a fiber input power of -3.0, +0.0, and +2.0 dBm, respectively, according to an embodiment of the present invention;

8 is a schematic diagram of noise correction factors of a 30.2 GB QPSK optical signal with a fiber input power of -3.0, +0.0, and +2.0 dBm, respectively, according to an embodiment of the present invention;

9 is a schematic diagram of optical signal to noise ratio monitoring values of a 30.2 GB QPSK optical signal with a fiber input power of -3.0, +0.0, and +2.0 dBm, respectively, according to an embodiment of the present invention;

FIG. 10 is a diagram showing error values of optical signal to noise ratio monitoring of a 30.2 GB QPSK signal according to an embodiment of the present invention.

detailed description

The invention will be described in detail below with reference to the drawings in conjunction with the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

It is to be understood that the terms "first", "second" and the like in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a particular order or order.

In this embodiment, a method for determining an optical signal-to-noise ratio OSNR is provided. FIG. 1 is a flowchart of a method for determining an optical signal-to-noise ratio OSNR according to an embodiment of the present invention. As shown in FIG. 1, the process includes the following steps. :

Step S102, determining a noise power correction factor k;

Step S104, correcting the noise power P _{N of the} detected optical signal according to the determined k;

Step S106, determining an optical signal to noise ratio OSNR based on the corrected noise power P _ASE .

Through the above steps, calculating the optical signal-to-noise ratio by using the corrected noise power can improve the calculation accuracy and reduce the calculation error, thereby solving the problem that the detected optical signal-to-noise ratio error is large in the related art, thereby achieving a reduction. The effect of the detected optical signal to noise ratio error.

其中，P_sig＝P_total-P_N，当然，也可以通过其他的公式确定k。In determining the above correction factor k, there may be multiple determination manners. In an optional embodiment, the total power P _{total of the} optical signal and the noise power P _{N of} the optical signal may be determined; according to the determined P _total and P _N determines the correction factor k. The above determination manner is only an example, and the correction factor k may be determined in other manners. Wherein, when k is determined according to the determined P _total and P _N , it can be determined by the following formula:

Where P _sig =P _total -P _N , of course, k can also be determined by other formulas.

In an alternative embodiment, P _total can be determined by the following formula: P _total = E{|y| ² }, where E{} is a second-order moment operation, y={y _n }, y _n is a pair The value of the optical signal at the nth point after the predetermined processing of the optical signal, y _n =Re(y _n )+i*Im(y _n ), Re(y _n ) is the real part, Im(y _n ) For the imaginary part, n is a positive integer; and/or, P _N is determined by the following formula: P _N =(std{|Re(y)|}) ² +(std{|Im(y)|}) ² , wherein , y={y _n }, y _n is the value of the optical signal at the nth point after the predetermined processing of the optical signal, y _n =Re(y _n )+i*Im(y _n ), Re( y _n ) is the real part, Im(y _n ) is the imaginary part, std{|Re(y)|} is the root mean square of the absolute value of the real part, and std{|Im(y)|} is the absolute value of the imaginary part Root mean square, n is a positive integer. The predetermined processing may include the following steps: performing coherent demodulation on the optical signal to obtain a real part and an imaginary part of the coherent demodulated optical signal; performing cross-resistance amplification and analog-to-digital conversion processing on the real part of the optical signal, The imaginary part of the optical signal is subjected to transimpedance amplification and analog-to-digital conversion processing; the real and imaginary parts subjected to transimpedance amplification and analog-to-digital conversion are subjected to digital signal processing; and the real and imaginary parts after digital signal processing are processed. Both are dispersion-balanced.

该P_ASE为修正后的噪声功率。Wherein, the noise power P _{N of the} detected optical signal according to the determined k includes: correcting P _N by the following formula:

The P _ASE is the corrected noise power.

通过如下公式确定OSNR：

其中，R_B为码元速率，B_r为测量光信噪比的参考带宽。通过以上的实施方式的描述，本领域的技术人员可以清楚地了解到根据上述 实施例的方法可借助软件加必需的通用硬件平台的方式来实现，当然也可以通过硬件，但很多情况下前者是更佳的实施方式。基于这样的理解，本发明的技术方案本质上或者说对现有技术做出贡献的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质(如ROM/RAM、磁碟、光盘)中，包括若干指令用以使得一台终端设备(可以是手机，计算机，服务器，或者网络设备等)执行本发明各个实施例的方法。In determining the optical signal-to-noise ratio (OSNR), the OSNR may be determined based on the corrected noise power P _ASE . In an optional embodiment, determining the optical signal-to-noise ratio OSNR based on the corrected noise power includes: determining the signal load by the following formula Noise ratio CNR:

The OSNR is determined by the following formula:

Where R _B is the symbol rate and B _r is the reference bandwidth for measuring the optical signal to noise ratio. Through the description of the above embodiments, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, by hardware, but in many cases, the former is A better implementation. Based on such understanding, the technical solution of the present invention, which is essential or contributes to the prior art, may be embodied in the form of a software product stored in a storage medium (such as ROM/RAM, disk, The optical disc includes a number of instructions for causing a terminal device (which may be a cell phone, a computer, a server, or a network device, etc.) to perform the methods of various embodiments of the present invention.

In the embodiment, a device for determining the optical signal-to-noise ratio (OSNR) is provided. The device is used to implement the foregoing embodiments and the preferred embodiments, and details are not described herein. As used below, the term "module" may implement a combination of software and/or hardware of a predetermined function. Although the apparatus described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware, is also possible and contemplated.

2 is a structural block diagram of an apparatus for determining an optical signal-to-noise ratio OSNR according to an embodiment of the present invention. As shown in FIG. 2, the apparatus includes a first determining module 22, a second determining module 24, and a third determining module 26, The device will be described.

The first determining module 22 is configured to determine a noise power correction factor k; the second determining module 24 is connected to the first determining module 22, and is configured to correct the noise power P _{N of the} detected optical signal according to the determined k; The determining module 26 is coupled to the second determining module 24 and configured to determine the optical signal to noise ratio OSNR based on the corrected noise power P _ASE .

3 is a structural block diagram of a first determining module 22 in an apparatus for determining an optical signal-to-noise ratio (OSNR) according to an embodiment of the present invention. As shown in FIG. 3, the first determining module 22 includes a first determining unit 32 and a second determining unit. 34. The first determining module 22 will be described below.

其中，P_sig＝P_total-P_N。当然，也可以通过其他公式确定k。The first determining unit 32 is configured to determine the total power P _{total of the} optical signal and the noise power P _{N of the} optical signal; the second determining unit 34 is connected to the first determining unit 32, and is set according to the determined P _total and P _N Determine k. The second determining unit 34 may include: determining k by the following formula:

Where P _sig =P _total -P _N . Of course, k can also be determined by other formulas.

Wherein, P _total :P _total =E{|y| ² } can be determined by the following formula, wherein E{} is a second-order moment operation, y={y _n }, and y _n is after the predetermined processing of the optical signal The value of the optical signal at _n values, y _n =Re(y _n )+i*Im(y _n ), Re(y _n ) is the real part, Im(y _n ) is the imaginary part, and n is positive An integer; and/or, P _N is determined by the following formula: P _N =(std{|Re(y)|}) ² +(std{|Im(y)|}) ² , where y={y _n } , y _n is the value of the optical signal at the nth point after the predetermined processing of the optical signal, y _n =Re(y _n )+i*Im(y _n ), and Re(y _n ) is the real part, Im(y _n ) is the imaginary part, std{|Re(y)|} is the root mean square of the absolute value of the real part, std{|Im(y)|} is the root mean square of the absolute value of the imaginary part, and n is positive Integer. The predetermined processing may include: performing coherent demodulation on the optical signal to obtain a real part and an imaginary part of the coherently demodulated optical signal; performing transimpedance amplification and analog-to-digital conversion processing on the real part of the optical signal, and virtualizing the optical signal The part performs transimpedance amplification and analog-to-digital conversion processing; performs digital signal processing on both the real part and the imaginary part after transimpedance amplification and analog-to-digital conversion processing; and performs dispersion-equalization on both the real part and the imaginary part after digital signal processing .

In an optional embodiment, the second determining module 24 includes: correcting P _N by the following formula:

通过如下公式确定OSNR：

其中，R_B为码元速率，B_r为测量光信噪比的参考带宽。图4是根据本发明实施例的基于二阶矩和噪声修正的光通信系统带内OSNR监测的整体流程图，如图4所示，该流程包括如下步骤：In an optional embodiment, the third determining module 26 includes: determining a signal carrier-to-noise ratio CNR by using the following formula:

The OSNR is determined by the following formula:

Where R _B is the symbol rate and B _r is the reference bandwidth for measuring the optical signal to noise ratio. 4 is an overall flow chart of in-band OSNR monitoring of an optical communication system based on second-order moment and noise correction according to an embodiment of the present invention. As shown in FIG. 4, the process includes the following steps:

Step S402, receiving the monitored optical signal, and performing coherent demodulation on the monitored optical signal to obtain a real part and an imaginary part of the monitored signal, and the real part and the imaginary part signal are respectively subjected to transimpedance amplification and analog-to-digital conversion, and then performed by the DSP. Dispersion equalization, the nth point of the signal after dispersion equalization is expressed as y _n =Re(y _n )+i*Im(y _n ), Re(y _n ) is the real part of the signal, and Im(y _n ) is The imaginary part of the signal;

Step S404, calculating the total power P _{total of the} received signal by calculating the second moment of {y _n }, wherein y={y _n } can be obtained, and thus the obtained second moment is P _total = E{|y | ² };

Step S406, calculating the noise power P _N by calculating the sum of the square roots of the absolute value of the real part of the signal and the absolute value of the imaginary part, P _N =(std{|Re(y)|}) ² +(std {|Im(y)|}) ² ;

其中P_sig＝P_total-P_N；Step S408, calculating an ASE noise power correction factor k by using

Where P _sig =P _total -P _N ;

Step S410, using the correction factor k, calculating the ASE noise power P _ASE by using

Step S412, calculating a signal carrier-to-noise ratio (CNR) by using

其中，SNR_dB即为OSNR的值，R_B是码元速率，B_r是测量光信噪比的参考带宽，通常为12.5GHz。Step S414, calculating an optical signal-to-noise ratio (OSNR) of the signal by using

Where SNR _{dB is} the value of OSNR, R _B is the symbol rate, and B _r is the reference bandwidth for measuring the optical signal-to-noise ratio, typically 12.5 GHz.

5 is a diagram of an in-band OSNR monitoring apparatus for an optical communication system based on second-order moment and noise correction according to an embodiment of the present invention. As shown in FIG. 5, an optical communication system in-band OSNR monitoring apparatus implemented in accordance with the method of the present invention may include The following modules: a coherent demodulation module 52, a cross-group amplification module 54, an analog-to-digital conversion module 56, and a DSP module 58, and an optical signal to noise ratio monitoring module 510.

The monitored optical signal first enters the coherent demodulation module 52. The coherent demodulation module 52 is composed of an optical mixer and a balanced detector. The coherent demodulation module 52 outputs the real and imaginary signals of the optical signal, and the real part of the optical signal. The imaginary part signal is respectively subjected to the transimpedance amplification of the cross-group amplification module 54 and the analog-to-digital conversion of the analog-to-digital conversion module 56, and then input into the DSP module 58 for dispersion equalization, and the real and imaginary signals output by the dispersion equalization module enter the optical signal noise. The optical signal to noise ratio monitoring module 510 includes a second order moment calculation, a noise power calculation, an ASE noise power correction, and an optical signal to noise ratio calculation.

The invention will be exemplified below in conjunction with specific embodiments:

At the transmitting end, a 30.2 GB offset multiplexed Quadrature Phase Shift Keying (QPSK) signal is generated and input to the fiber link. In order to measure the adaptability to different fiber input powers in the embodiments of the present invention, the signal power of the input fiber is changed to -3.0 dBm, 0.0 dBm, and +2.0 dBm, respectively. In order to measure the adaptability of the filtering effect in the fiber link in the embodiment of the present invention, the filter bandwidth is changed to 28 GHz and 30.2 GHz, respectively.

6 is a schematic diagram of total signal power after coherent reception of a 30.2 GB QPSK optical signal with a fiber input power of -3.0, +0.0, and +2.0 dBm, respectively, according to an embodiment of the present invention; FIG. 7 is a fiber input power according to an embodiment of the present invention. Schematic diagram of total noise power after coherent reception of 30.2 GB QPSK optical signals of -3.0, +0.0, +2.0 dBm, respectively. Figure 6 and Figure 7 show the total signal power and total noise power after the coherent reception of the 30.2 GB QPSK optical signals with the fiber-input powers of -3.0, +0.0, and +2.0 dBm, respectively, as a function of the reference signal-to-noise ratio. It can be seen from FIG. 6 that the total power of the coherent received signal does not change much with the reference optical signal-to-noise ratio and the fiber-input power. As can be seen from Fig. 7, the total power of the noise in the coherent received signal varies significantly with the power of the fiber. In order to characterize the change of noise power under different fiber input power conditions, a noise correction factor is defined. FIG. 8 is a 30.2 GB QPSK optical signal with a fiber input power of -3.0, +0.0, +2.0 dBm, respectively, according to an embodiment of the present invention. Schematic diagram of the noise correction factor. The noise power is corrected by using a correction factor to obtain an optical signal to noise ratio of the optical signal to be measured. FIG. 9 is a 30.2 GB QPSK optical signal with a fiber input power of -3.0, +0.0, and +2.0 dBm, respectively, according to an embodiment of the present invention. Schematic diagram of optical signal to noise ratio monitoring values. 10 is a schematic diagram showing error values of optical signal-to-noise ratio (SNR) monitoring of a 30.2 GB QPSK signal according to an embodiment of the present invention. As shown in FIG. 10, a 30.2 GB offset-multiplexed QPSK signal with a reference optical signal-to-noise ratio of 15.0 to 25.0 dB is shown. Monitoring, the optical signal-to-noise ratio monitoring error is within ±1.0 dB under different fiber input power and different filter bandwidth conditions.

In the above embodiment, the second-order moment and the noise power correction method are adopted, and the monitoring error in the range of the reference signal-to-noise ratio of 15.0 to 25.0 dB is within ±1.0 dB, and is independent of the filter effect on the fiber link. Compared with the related art, the optical signal to noise ratio monitoring method provided in the embodiment of the present invention is simple, and the monitoring accuracy is improved, and is applicable to different modulation formats, Monitoring of fiber link signals with different fiber power and different filtering effects. The system used in the invention comprises coherent demodulation, cross-group amplification, analog-to-digital conversion and dispersion equalization and optical signal-to-noise ratio calculation modules, and the optical signal-to-noise ratio of the optical signal is monitored by these modules, and good effects are obtained.

It should be noted that each of the above modules may be implemented by software or hardware. For the latter, the foregoing may be implemented by, but not limited to, the foregoing modules are all located in the same processor; or, the modules are located in multiple In the processor.

Embodiments of the present invention also provide a storage medium. Optionally, in the embodiment, the foregoing storage medium may be configured to store program code for performing the following steps:

S1, determining a noise power correction factor k;

S2, correcting the noise power P _{N of the} detected optical signal according to the determined k;

S3, determining an optical signal to noise ratio OSNR according to the corrected noise power P _ASE .

Optionally, in the embodiment, the foregoing storage medium may include, but is not limited to, a USB flash drive, a Read-Only Memory (ROM), and a Random Access Memory (RAM). A variety of media that can store program code, such as a hard disk, a disk, or an optical disk.

For example, the specific examples in this embodiment may refer to the examples described in the foregoing embodiments and the optional embodiments, and details are not described herein again.

It will be apparent to those skilled in the art that the various modules or steps of the present invention described above can be implemented by a general-purpose computing device that can be centralized on a single computing device or distributed across a network of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps thereof are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Industrial applicability

As described above, the method and apparatus for determining the optical signal-to-noise ratio OSNR provided by the embodiments of the present invention have the following beneficial effects: solving the problem that the detected optical signal-to-noise ratio error is large in the related art, and further reducing The effect of the detected optical signal to noise ratio error.

Claims (10)

A method for determining an optical signal to noise ratio (OSNR) includes: Determining a noise power correction factor k; Correcting the noise power P _{N of the} detected optical signal according to the determined k; The optical signal to noise ratio OSNR is determined based on the corrected noise power P _ASE . The method of claim 1 wherein determining the noise power correction factor k comprises: Determining a total power P _{total of} the optical signal and a noise power P _{N of} the optical signal; Determining the k according to the determined P _total and the P _N includes: determining the k by the following formula:

Where P _sig =P _total -P _N . The method of claim 2, wherein The P _total is determined by the following formula: P _total = E{|y| ² }, where E{} is a second-order moment operation, y={y _n }, y _n is after performing predetermined processing on the optical signal The value of the optical signal at the nth point, y _n =Re(y _n )+i*Im(y _n ), Re(y _n ) is the real part, Im(y _n ) is the imaginary part, n is Positive integer; and/or, The P _N is determined by the following formula: P _N =(std{|Re(y)|}) ² +(std{|Im(y)|}) ² , where y={y _n }, y _n is The value of the optical signal at the nth point after the predetermined processing of the optical signal, y _n =Re(y _n )+i*Im(y _n ), and Re(y _n ) is the real part, Im ( y _n ) is the imaginary part, std{|Re(y)|} is the root mean square of the absolute value of the real part, std{|Im(y)|} is the root mean square of the absolute value of the imaginary part, and n is a positive integer; The predetermined processing includes: performing coherent demodulation on the optical signal to obtain a real part and an imaginary part of the coherently demodulated optical signal; performing transimpedance amplification and analog-to-digital conversion processing on the real part of the optical signal Performing transimpedance amplification and analog-to-digital conversion processing on the imaginary part of the optical signal; performing digital signal processing on both the real part and the imaginary part subjected to transimpedance amplification and analog-to-digital conversion processing; Both the ministry and the imaginary part are dispersion-balanced. The method of claim 1 wherein modifying the noise power P _{N of the} detected optical signal based on the determined k comprises: The P _N is corrected by the following formula:

The method of claim 1 wherein determining the optical signal to noise ratio OSNR based on the corrected noise power P _ASE comprises: The signal carrier-to-noise ratio CNR is determined by the following formula:

The OSNR is determined by the following formula:

Where R _B is the symbol rate and B _r is the reference bandwidth for measuring the optical signal to noise ratio. A device for determining an optical signal to noise ratio OSNR, comprising: a first determining module, configured to determine a noise power correction factor k; a second determining module, configured to correct a noise power P _{N of the} detected optical signal according to the determined k; The third determining module is configured to determine the optical signal to noise ratio OSNR according to the corrected noise power P _ASE . The apparatus of claim 6, wherein the first determining module comprises: a first determining unit, configured to determine a total power P _{total of} the optical signal and a noise power P _{N of} the optical signal; a second determining unit, configured to determine the k according to the determined P _total and the P _N , including determining the k by:

Where P _sig =P _total -P _N . The apparatus according to claim 7, wherein The P _total is determined by the following formula:

Where E{ } is a second-order moment operation, y={y _n }, y _n is the value of the optical signal at the nth point after the predetermined processing of the optical signal, y _n =Re(y _n ) +i*Im(y _n ) _, Re(y _n ) is the real part, Im(y _n ) is the imaginary part, n is a positive integer; and/or, The P _N is determined by the following formula: P _N =(std{|Re(y)|}) ² +(std{|Im(y)|}) ² , where y={y _n }, y _n is The value of the optical signal at the nth point after the predetermined processing of the optical signal, y _n =Re(y _n )+i*Im(y _n ), and Re(y _n ) is the real part, Im ( y _n ) is the imaginary part, std{|Re(y)|} is the root mean square of the absolute value of the real part, std{|Im(y)|} is the root mean square of the absolute value of the imaginary part, and n is a positive integer; The predetermined processing includes: performing coherent demodulation on the optical signal to obtain a real part and an imaginary part of the coherently demodulated optical signal; performing transimpedance amplification and analog-to-digital conversion processing on the real part of the optical signal Performing transimpedance amplification and analog-to-digital conversion processing on the imaginary part of the optical signal; performing digital signal processing on both the real part and the imaginary part subjected to transimpedance amplification and analog-to-digital conversion processing; Both the ministry and the imaginary part are dispersion-balanced. The apparatus of claim 6, wherein the second determining module comprises: The P _N is corrected by the following formula:

The apparatus of claim 6, wherein the third determining module comprises: The signal carrier-to-noise ratio CNR is determined by the following formula:

The OSNR is determined by the following formula:

Where R _B is the symbol rate and B _r is the reference bandwidth for measuring the optical signal to noise ratio.

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