OPTICAL TRANSMISSION SYSTEM

摘要

PROBLEM TO BE SOLVED: To prevent the deterioration of optical signals and to minimize the decrease in the entire optical transmission capacity by eliminating unwanted signal light generated in wavelength areas other than a wavelength channel used inside an optical signal group in respective upper and lower transmission directions, and at the same time amplifying and relaying the signal light of upper and lower wavelength channels coexisting inside the same coated topical fiber. SOLUTION: Signal light of a wavelength channel for incoming and of a wavelength channel for outgoing coexisting inside the same coated optical fiber is amplified at the same time altogether for each group of the incoming and outgoing wavelength channels or for each sub group less than an arbitrarily determined wavelength cannel number or for each sub group less than the wavelength channel number inside the group of the incoming and outgoing wavelength channels, and the optical signals are relayed. In such a light amplifier, unwanted light of wavelength areas other than the signal wavelength channel is eliminated, diffusion of a spectrum generated due to the instability in an abnormal dispersion area of a positive dispersion value is suppressed and crosstalks between adjacent wavelengths are suppressed.