RAMAN AMPLIFIER AND OPTICAL COMMUNICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To reduce the variation of gains in a Raman amplifier and an optical communication system using it and also to reduce the fluctuation of gains for every optical fiber being a gain medium. SOLUTION: This amplifier is a Raman amplifier performing the Raman amplification of an incident signal light and is provided with optical fibers being gain media of the Raman amplification, an exciting light source exciting the optical fibers, an exciting light from the light source, a multiplexer multiplexing the signal light, a gain detecting means detecting the Raman gain of the amplifier and a control circuit electrically driving the exciting light source based on the detected gain value obtained in the detecting means and the amplifier keeps the Raman gain to be constant when the total value of the power of the incident signal light and the kind and length of the optical fiber are changed.