Gain-clamped S-band discrete Raman amplifier

In summary, we have demonstrated, for the first time to our knowledge, a gain-clamped discrete Raman amplifier in the S-band. The device achieves peak net gain over 22 dB, and a gain variation of only 0.3 dB for signal input power ranging from -20 dBm to 2.7 dBm. Unlike conventional gain-clamping designs, an extinction ratio between signal and lasing wavelength of over 30 dB is achieved. This new technique suppresses instability due to randomly-polarized ASE and double Rayleigh scattering (DRS) (hence noise figure) for small signal input power under high pump power, as well as power surges due to transient effects in Raman amplifiers. This promises a viable technology to provide gain bands not currently available from traditional doped fiber amplifiers.