Patent ID: 6985285
Filing Date: 2006-01-10
Classification: H01S,H04B

Abstract:
1. An optical transmission system which includes an upstream line and a downstream line through which signal light is propagated in directions opposite to each other, for Roman amplifying and transmitting the signal light by supplying pumping light generated in a pumping light source common to each line to a plurality of transmission sections set for each of said lines respectively, wherein said plurality of transmission sections of each line comprise a hybrid transmission path configured by connecting a positive dispersion fiber having positive dispersion relative to the signal light and a negative dispersion fiber having negative dispersion relative to the signal light, and at the same time, include transmission sections in which average wavelength dispersion obtained by summing up cumulative wavelength dispersion in said positive dispersion fiber and said negative dispersion fiber is positive, and transmission sections in which the average wavelength dispersion is negative, and when there are points of sign difference where the pumping light generated by the pumping light source common to each line is supplied to the transmission section of one line in which the average wavelength dispersion is positive and the transmission section of the other line in which the average wavelength dispersion is negative, the hybrid transmission path used for the transmission sections of each line, which correspond to said points of sign difference, has a configuration such that said positive dispersion fiber and said negative dispersion fiber which constitute each line are set so that a difference of Raman gain occurring between each of the transmission sections is substantially reduced.