Patent ID: 6222655
Filing Date: 2001-04-24
Classification: H04B,H04J

Abstract:
A wavelength division multiplex optical amplification transmission system comprising:a lightwave transmitting terminal station for multiplexing a plurality of optical signals having wavelengths different from each other and transmitting the optical signals;a transmission line comprising a plurality of optical amplifiers serially connected with a plurality of optical filters; anda lightwave receiving terminal station for receiving the plurality of optical signals transmitted by said lightwave transmitting terminal station via said transmission line,wherein: each of said plurality of optical amplifiers has a single peak gain wavelength characteristic in which a gain maximum wavelength value with a maximum gain exists in a wavelength range containing all wavelengths of the plurality of optical signals, the gain simply decreases as a distance from the gain maximum wavelength value increases within the wavelength range, and each said gain wavelength characteristic is asymmetrical with respect to the gain maximum wavelength value;each of said plurality of optical filters exhibits a loss wavelength characteristic which has a characteristic of a single peak in a respective predetermined wavelength range, and each respective predetermined wavelength range is included in the wavelength range of the optical amplifier having the single peak; anda combined loss wavelength characteristic obtained by adding the loss wavelength characteristics of each of said plurality of optical filters is relatively coincident in terms of values with a combined gain wavelength characteristic obtained by adding the gain wavelength characteristics of each of said plurality of optical amplifiers within the wavelength range, said optical filters having at least two different loss wavelength characteristics.