Research On Optical Performance Monitoring Based On Grating

As the capacity of network increase rapidly, the optical communication is evolving intolarge capacity, high speed and long haul system. In order to use the bandwidth resourcesmore effectively, channel intervals of WDM optical fiber communication system isbecoming more and more narrow. In order to guarantee all of the optical channels operatingwell, we should monitor the wavelength, power and power, signal-to-noise ratio of opticalchannel in the key position of the network. In this way, optical performancemonitoring(OPM) is important. In this thesis, the author improve the traditional opticaldispersion structure with grating, introduce a OPM device based on grating. By zemax andmatlab, Simulation and analysis have been done to simulate monitoring channel parametersof a16channel WDM signal with200G channel spacing.Firstly, this thesis introduces the application of OPM in optical network and varioustypes of OPM’s basic principle and their advantages and disadvantages. By zemax simulating,the author analyze the character of the optical dispersion structure with grating. Thesimulation results show that,in that structure, both of the linear dispersion and the spot sizecan be doubled by the use of asymmetric lens structure, and the size of the device can be thesame. In this way, we can make the distinguishability Increase.Secondly, the model built by matlab indicate that, the OPM designed in this thesis canaccurately monitor the channel center wavelength and the channel power. The OPM canmonitor signal-to-noise ratio accurately if we monitor the noise out of the bandwidth.But ifwe monitor the noise in the bandwidth of the channels, the SNR error is big, the inverseconvolution is needed. In this thesis, a inverse convolution method about matrix isintroduced. The study indicate that, the inverse convolution effect is good if the ratio of thespot size and the detector size is small.