Nonlinear enhancement in photonic crystal waveguides with spot-size converter

Abstract

We evaluated the nonlinear enhancement in slow-light photonic crystal waveguides. The devices butt-joined to Si wire waveguides were fabricated on SOI substrate using CMOS-compatible process. Integrating spot size converter to the device allows high input power and clear enhancement. The coupling loss between lensed fiber and the wire was 3 - 4 dB. We observed two-photon absorption, self-phase modulation and four-wave mixing in the low power regime of less than 1 W, which is assisted by low-dispersion slow light. Such slow light can be exploited for compact functional components such as optical limiters and wavelength converters.