Patent ID: 6885498

Claim:
A multi-stage optical amplifier, comprising: an amplifier including at least a distributed Raman amplifier fiber and a discrete amplifier fiber, the amplifier configured to be coupled to at least one signal source that produces a plurality of signal wavelengths λ s and at least a first pump source that produces one or more pump beam wavelengths λ p ; a signal input port coupled to the amplifier; a signal output port coupled to the amplifier, the distributed Raman and discrete amplifier fibers being positioned between the signal input port and the signal output port; a first pump input port coupled to a first end of the distributed Raman amplifier fiber and operable to introduce a first pump signal to the distributed Raman amplifier fiber; a second pump input port coupled to a second end of the distributed Raman amplifier fiber and operable to introduce a second pump signal to the distributed Raman amplifier fiber, the first end being located closer to the signal input port than the second end, wherein the first pump signal traverses the distributed Raman amplifier fiber in a first direction and the second pump signal traverses the distributed Raman amplifier in a direction counter to the first direction; and a third pump input port coupled to the discrete amplifier fiber.