A tunable multiple Stokes cw fiber Raman oscillator

A broadly tunable source of coherent cw radiation has been achieved by the use of a multiresonant cavity for multiple Stokes oscillation in a fused-silica fiber Raman oscillator. Each order of tunable Stokes emission acts as a pump for the next higher order; a net tunability of several times the intrinsic Raman gain bandwidth is obtained. With 8 W of 5145-Å pump radiation coupled into a 100-m-long single-mode fiber, four orders of Stokes oscillation have been obtained, yielding over 350 Å of tuning in the 5200–5660-Å spectral range.