Enhanced spontaneous Raman scattering in silicon photonic crystal waveguides on insulator

We study the spontaneous Raman scattering in a W1 photonic crystal waveguide on silicon-on-insulator where the lower silica cladding remains. Despite the vertical asymmetry that exists in such a waveguide, we numerically and experimentally show that the propagation losses at the pump and the Stokes wavelengths remain low enough to allow a significant exaltation of the spontaneous Raman scattering. In particular, we observe a reshaping of the Raman spectrum and a more than ten-fold enhancement of the Raman scattering efficiency in a W1 photonic crystal waveguide as compared to a single-mode ridge waveguide.