Distributed fiber Raman amplifiers with incoherent pumping

Distributed fiber Raman amplifier (DFRA) with incoherent pumping is investigated and its performance is compared to that with the conventional coherent pumping. It is shown that increasing the spectral bandwidth of incoherent pumping source can reduce the Raman gain ripple significantly, and degrade noise figure slightly at short wavelengths, compared to coherent pumping. To achieve the same gain flatness, the number of pumps for broad-band DFRAs with incoherent pumping can be significantly reduced compared to the coherent pumping.