Net optical gain in a low loss silicon-on-insulator waveguide by stimulated Raman scattering

We observe for the first time net optical gain in a low loss silicon waveguide in silicon-on-insulator (SOI) based on stimulated Raman scattering with a pulsed pump laser at 1.545 mum. We show that pulsed pumping with a pulse width narrower than the carrier recombination lifetime in SOI significantly reduces the free carrier generation rate due to two-photon absorption (TPA) in silicon. For a 4.8 cm long waveguide with an effective core area of similar to1.57 mum(2), we obtained a net gain of 2 dB with a pump pulse width of similar to17 ns and a peak pump power of similar to470 mW inside the waveguide. (C) 2004 Optical Society of America.