cw Raman fiber amplifier

cw Raman amplification has been observed in a hollow fused silica fiber, inside diameter 5 μm, 5 m long, filled with benzene. Using a krypton laser pump, amplification of the 992−cm−1 Stokes Raman line has been obtained at pump wavelengths 5682, 6471, and 7525 A. The pump powers determined by measuring the slightly attenuated output from the fiber were 17, 25, and 17 mW, respectively. The corresponding amounts of power in the input laser pump before the launching optics were 70, 85, and 75 mW.