Patent ID: 7162129

Claim:
An optical transmission system comprising a transmitter for outputting signal light and an optical transmission line for transmitting the signal light outputted from said transmitter, said optical transmission line comprising a first optical fiber disposed in the most upstream part of said optical transmission line and a second optical fiber spliced to said first optical fiber, wherein said first optical fiber has negative chromatic dispersion, an absolute value of a dispersion slope of not larger than 0.03 ps/nm 2 /km, and a non-linear constant γ larger than that of said second optical fiber at any one wavelength of the signal light, where γ=(2πn 2 )/(λA eff ), λ is a wavelength of signal light, and n 2 is the non-linear refractive index, and the absolute value of the sum of overall dispersion of said first optical fiber and overall dispersion of said second optical fiber is smaller than the absolute value of the overall dispersion of said first optical fiber at said one wavelength.