OPTICAL RELAY AMPLIFIER, OPTICAL COMMUNICATION SYSTEM AND OPTICAL COMMUNICATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide an optical relay amplifier capable of utilizing an optical bandpass filter that has narrow-band transmission characteristics, and suppressing noise generated in an optical amplification device, an optical communication system including the optical relay amplifier, and an optical communication method of the optical communication system.SOLUTION: An optical relay amplifier 1 includes: a relay amplification unit 5 for amplifying an inputted optical signal; an optical bandpass filter 6 which has a predetermined transmission bandwidth and to which the optical signal amplified by the relay amplification unit 5 is coupled; a wavelength determination unit 9 for monitoring a wavelength difference between a wavelength of the inputted optical signal and a central wavelength of the transmission bandwidth of the optical bandpass filter 6; and a wavelength conversion unit 8 which is disposed between the relay amplification unit 5 and the optical bandpass filter 6 and, when the wavelength difference monitored by the wavelength determination unit 9 is greater than a predetermined specified value, converts the wavelength of the optical signal amplified by the relay amplification unit 5 in such a way that the wavelength of the optical signal is included in the transmission bandwidth of the optical bandpass filter 6.