Noise properties of a Raman amplifier.

We present the first measurements of the noise properties of a Raman optical amplifier. Measurements on CW Raman amplified optical signals from a 1.5micron single frequency laser in 32km of silica fiber, pumped by a 1.45micron color center laser, reveals that the main noise source is the shotnoise generated in the receiver due to the spontaneous Raman radiation. For signal levels down to -50 dBm, no excess noise due to the Raman process could be detected.