Nonlinear absorption and Raman gain in helium-ion-implanted silicon waveguides

We study whether helium ion implantation can reduce the carrier lifetime and thus reduce the density of two-photon-absorption-generated free carriers. Our experiments and theoretical model show that helium ion implantation into silicon waveguides can successfully reduce the free-carrier losses and allow net gain to be attained by cw-pumped stimulated Raman scattering without requiring reverse bias to remove the photogenerated free carriers.