Patent ID: 6868203

Claim:
An optical transmission system, comprising: an optical transmitter including a direct modulation light source, said optical transmitter outputting signal light in a signal wavelength band; an optical receiver receiving the signal light; an optical fiber transmission line, as a transmission medium through which signal light where a plurality of signal channels are multiplexed propagates, provided between said optical transmitter and said optical receiver; and a dispersion compensator provided on one of an optical path between the signal transmitting end of said optical transmitter and the signal entering end of said optical fiber transmission line, and an optical path between the signal emitting end of said optical fiber transmission line and the signal receiving end of said optical receiver, said dispersion compensator dispersion-compensating for a chromatic dispersion of signal channel group in a second wavelength band other than a first wavelength band which includes a zero-dispersion wavelength of said optical fiber transmission line among the plurality of signal channels, wherein, when a bit rate is B (Gb/s) at a specific wavelength in the second wavelength band where a total chromatic dispersion in said optical fiber transmission line and said dispersion compensator becomes the highest, a chromatic dispersion value at the specific wavelength is greater than 0 (ps/nm) but 7500/B 2 (ps/nm) or less, and wherein, in said entire optical transmission system, loss in each signal channel in the second wavelength band is smaller than the highest loss among losses in the signal channels in the first wavelength band.