Patent ID: 11095388

Abstract:
The de-multiplexing unit 2 de-multiplexes an inputted optical wavelength multiplexed signal into a first optical wavelength multiplexed signal having a first wavelength band and a second optical wavelength multiplexed signal having a second wavelength band in a longer wavelength band than the first wavelength band. The first optical amplifier 3 amplifies the first optical wavelength multiplexed signal. The second optical amplifier 4 amplifies the second optical wavelength multiplexed signal. The multiplexer 5 multiplexes the amplified first optical wavelength multiplexed signal and the amplified second optical wavelength multiplexed signal and outputs the multiplexed signal to a Raman amplifier 6. The first optical amplifier 3 adjusts the amplification rate of the first optical wavelength multiplexed signal so that the intensity of light in the second wavelength band is compensated for by the Raman effect in the Raman amplifier 6.