In-line BSRS optical signal amplification using fibre nonlinear coupler

Describes a scheme which uses a nonlinear fibre coupler with in-line backward stimulated Raman scattering (BSRS) optical signal amplification for long-span optical fibre communications is presented. The introduction of a nonlinear optical fibre coupler to the in-line fibre Raman amplification promises to circumvent a considerable power penalty which amounts to more than 6 dB when conventional (linear) coupling devices are used.