SUPERVISION OF PERFORMANCE IN OPTICAL TRANSMISSION SYSTEM AND TROUBLESHOOTING

摘要

PROBLEM TO BE SOLVED: To measure the channel performance in each amplification stage without using any complicated highly expensive measuring instrument. SOLUTION: Individual channels in optical signals multiplexed by means of a multiplexer 120 are modulated with a specific low-frequency tone. The specific tone frequency is selected so that the selected frequency may become lower than the cutting-off low-frequency of one of the other information encoded on an optical signal. The channel electrode of each channel measures the power of the specific low-frequency tone in each stage of an optical amplifier 130 in a network by using a low-cost monitor after each stage. The whole optical output power of the amplifier 130 is similarly measured by using a monitor in the amplifier 130. Therefore, any one of the other components in the network does not require complicated inspections. Since each optical amplifier has its own monitor for deciding the state of each optical channel, a fault which occurs in the network can be located easily and quickly to a specific optical amplifier and a specific channel.