Cascaded silicon Raman lasers as mid-infrared sources

It is shown by numerical simulations that cascaded silicon Raman lasers, in which the pump light undergoes multiple Stokes shifts in a silicon waveguide, can efficiently convert near-IR to mid-IR radiation. For pump wavelengths significantly below 2 pro, two-photon-absorption-induced free-carrier absorption degrades conversion efficiency, and the effective carrier lifetime determines the shortest possible pump wavelength.