Optical transmission networks based on Dense Wavelength Division Multiplexing(DWDM) system make up the physical layer of the whole telecommunication system.To fit the demands for the system application and development
researching and producing OPM(In-line optical performance monitor) becomes a hot-spot in many device-supply corporations recently.A typical OPM can monitor the parameters of channel optical power
center wavelength and Optical Signal-Noise Ratio(OSNR) and so on.In this article