LIGHT SIGNAL-TO-NOISE RATIO MEASURING DEVICE IN WAVELENGTH DIVISION MULTIPLEXING APPARATUS

摘要

PURPOSE: A light signal-to-noise ratio measuring device is provided to measure light SNR(Signal-to-Noise Ratio) without additionally using a filter for separating light signals of each signal channel from the light signal wavelength-division-multiplexed in a WDM light transmitting device. CONSTITUTION: A light signal-to-noise ratio measuring device has; a wavelength division reverse multiplexing device(100) for separating the light signal of the noise channel that the waves are differently set; a light tap(102,104) for separating a specific ratio of the light signal among the light signal of the signal channel near the noise channel; the 1st light detecting device(106) for converting into the electric signal by detecting the light signal separated by the light tap; the 2nd light detecting device(108) for converting into the electric signal by detecting the light signal of the noise channel separated by the wavelength division reverse multiplexing device; a calculating unit(114) for calculating the light signal-to-noise by calculating the ratio of the strength of the electric signal outputted.