High Gain, Low Noise, Spectral-Gain-Controlled, Broadband Lumped Fiber Raman Amplifier

We demonstrate an 80 nm bandwidth (extending from 1529 to 1609 nm), dual-stage, diode-pumped, lumped Raman amplifier using a relatively short total length (2 km) of highly nonlinear fiber. The impact of Rayleigh back scattering is mitigated and the build-up of thermally generated wavelength dependent noise is controlled by suitably adjusting the spectral gain profile in the two amplifier stages. In this way a high overall gain of 27 dB with 2.6 dB gain flatness and an average noise figure of 5.8 dB with <; 1 dB variation is achieved across the full amplifier bandwidth.