Signal Pulse Distortion Induced by Stimulated Raman Scattering in High Power Double-Clad Fiber Amplifiers

In this letter, the evolution of the stimulated Raman scattering effect on pulse amplification for an Yb-doped double-clad fiber amplifier is investigated. It is experimentally demonstrated that the generated Raman-Stokes pulses occur together with the signal pulse, which causes severe distortion of the output signal pulse. The signal and Raman spectral components are discriminated and their temporal evolution dependence on peak power is analyzed.