Patent ID: 6865016

Claim:
An optical transmission system comprising: a first station which multiplexes a plurality of optical signals within a wavelength bandwidth to thereby provide a multiplexed optical signal, and transmits the multiplexed optical signal; an optical repeater which amplifies the multiplexed optical signal from the first station and outputs the amplified multiplexed optical signal, the optical repeater including: first means for maintaining flatness of gain within the wavelength bandwidth, the first means including: a first-stage optical amplifier which amplifies an input optical signal to thereby output a first-stage amplified optical signal, the first-stage amplified optical signal passing through a first optical isolator and then a second optical isolator, and a second-stage optical amplifier which receives the first-stage amplified optical signal after passing through the first and second optical isolators, and amplifies the received first-stage amplified optical signal; and second means for compensating for dispersion of the first-stage amplified optical signal after the first-stage amplified optical signal passes through the first optical isolator and before the first-stage amplified optical signal passes through the second optical isolator, and a second station which receives the multiplexed optical signal output from the optical repeater.