METHOD FOR IDENTIFYING DEFECT IN WDM OPTICAL NETWORK

摘要

PROBLEM TO BE SOLVED: To enable to monitoring the change in the number of channels and the change in the common power of the whole channels by permitting signal power which is transmitted to a system and amplification natural radiation (ASE) power which is generated by means of local erbium doped fiber amplifier(EDFA) to detect the change in the number of the channels through the use of a characteristic which indicates different action when upstream loss changes. SOLUTION: A first DFB laser 12 is used as the source of a monitoring the channel and the second DFB laser 14 is used for simulating another signal channel. Two intermediate amplifiers for pumping two steps of EDFA 16 and 18 by dual (multiplexed) pumps are used for amplifying light from the DFB lasers 12 and 14 so that proper input power is obtained in the respective channels. A 10% tap 22 is arranged at the output end of EDFA 20 so as to monitor the output power which is required for analysis. The monitor channel and ASE are selected by the band-pass WDM 24 and the succeeding filters 26 and 28.