1.3 /spl mu/m Raman fiber amplifier pumped by chromium-doped forsterite laser

A 1.3 /spl mu/m Raman fiber amplifier pumped by a chromium-doped forsterite laser and spliced with a fiber Bragg grating shows a high efficiency and noise figure of 4.7 dB/spl plusmn/0.3 dB. The role of the grating was to return the residual pump power to the Raman fiber, which substantially increased the gain efficiency. The amplifier was investigated in forward and backward pump traveling configurations. A twofold gain efficiency was achieved with the help of a fiber grating returning the residual pump back into the fiber. The forward pump configuration exhibited a higher gain efficiency and a lower NF than the backward pump configuration.