Control of transient regime of stimulated Raman scattering using hollow-core PCF

Abstract

Accurate control over the transient and steady-state regimes of stimulated Raman amplification is achieved in hydrogen-filled hollow-core photonic crystal fiber via the control of the fiber length and the internal gas pressure. The experimental evolution of the characteristic time that determines the limit between the two scattering regimes is shown to closely follow the theoretical prediction. Transient amplification is observed for pump-laser pulse lengths longer than 10 times the Raman dephasing time, opening new prospects for the generation of a coherent optical frequency comb using ultralong pump-laser pulses (>100 ns).