Wavelength division multiplexed signal light monitoring equipment, monitoring method, and optical transmission system

摘要

PROBLEM TO BE SOLVED: To provide a wavelength multiplex signal light monitoring device, a monitor method and an optical transmission system employing the method, that can acquire monitor data as to states of a plurality of signal lights included in a wavelength multiplex signal light and facilitate monitoring of the wavelength multiplex signal light while suppressing a large sized scale, complicatedness and high cost. SOLUTION: An optical filter 16 capable of variably controlling a loss gradient of a wavelength multiplex signal light branched for monitoring from an input optical guide path 12 and an output optical guide path 13 being major optical paths for optical transmission is placed on a monitor optical guide path 14 of the wavelength multiplex signal light monitor 1. Then a plurality of loss tilts are sequentially set to the optical filter 16 and a photo diode 20 detects a wavelength multiplex signal light passing through the optical filter 16 by each loss tilt to obtain monitor data of the wavelength multiplex signal light from the detected data.