Raman amplification in a P₂O₅-doped optical fiber

The 1.5-μm-band optical amplification characteristics owing to stimulated Raman scattering in a highly P₂O₅-doped single-mode fiber are experimentally investigated. With the combination of a 1.32-μm pump and a 1.59-μm signal, a net power gain of 15.4 dB at a wavelength of 1.59 μm is obtained for a pump power of 15 W. The test fiber is an 800-m-long single-mode fiber in which the core region is doped with 17 mol % P₂O₅. The 3-dB gain bandwidth is 23.5 cm⁻¹, and the optical power ratio of the amplified signal to the spontaneous emission is about 25 dB for a bandwidth of 1 nm at the first Stokes line.