Patent ID: 7924497

Claim:
An optical communication system comprising: a transmitter configured to transmit an aggregate optical signal comprising plurality of optical signals at different associated wavelengths in a signal bandwidth; a receiver configured to receive said aggregate optical signal and detect data modulated on said plurality of optical signals; and a transmission path extending between said transmitter and said receiver, said transmission path comprising, at least first and second amplifiers separated by a transmission span of at least 120 km in length, at least the first amplifier being a hybrid Raman/EDFA amplifier comprising: a Raman portion comprising a transmission path segment configured to be pumped by at least one Raman pump to impart Raman gain to at least a portion of said signal bandwidth, an EDFA portion comprising at least one erbium-doped fiber configured to be pumped by at least one EDFA pump to impart EDFA gain to at least a portion of said signal bandwidth, and a gain flattening filter coupled between said Raman portion and said EDFA portion of said hybrid Raman/EDFA with no gain flattening filter coupled to an output of said EDFA portion, wherein said at least one Raman pump and said at least one EDFA pump are configured to pump said transmission path segment and said erbium-doped fiber segment, respectively, to achieve an amplifier gain with amplified spontaneous emission (ASE) noise generated by said Raman portion exceeding ASE noise generated by said EDFA portion.