OPTICAL AMPLIFICATION RELAY SYSTEM

摘要

A relay station (10) detects any abnormality in a signal light and a monitoring light arriving from a terminal station (1) or a relay station (20) and controls the operation of optical amplifiers (11, 12) and the monitoring light based on the results of the detection. If both the signal light and monitoring light arriving from the terminal station (1) through a downstream light transmission line are abnormal, the downstream optical amplifier (11) stops its amplification operation, and a monitoring controller (13) stops the amplification operation of the upstream optical amplifier (12) and the transmission of the upstream monitoring light to the terminal station (1).