Patent ID: 7342714

Claim:
A hybrid optical amplifier for amplifying an optical signal transmitted on an optical fiber and having a frequency range, the amplifier comprising: at least one Raman pump coupled to the fiber, having a gain within the frequency range and creating a Raman amplified signal; a band demultiplexer for splitting the Raman amplified signal propagating in the fiber into a plurality of band signals having band frequency ranges; at least one semiconductor optical amplifier (SOA), each said SOA connected for amplifying a band signal of the plurality of band signals, and having a gain within the band frequency range of the band signal; and a band multiplexer for recombining the band signals after amplification; wherein the at least one Raman pump comprises three Raman pumps, outputs of which are multiplexed by a pump multiplexer; and wherein the optical signal comprises at least two frequency channels having a null frequency range between the channels, and wherein at least one of the Raman pumps comprises a pump laser having a frequency within the null frequency range.