White, T. P.O'Faolain, L.Li, JuntaoAndreani, L. C.Krauss, T. F.2016-04-262016-04-261094-4087http://hdl.handle.net/1885/101126We report on the fabrication and characterization of silicon photonic crystal waveguides completely embedded in silica. These waveguides offer a robust alternative to air-membranes and are fully compatible with monolithic integration. Despite the reduced refractive index contrast compared to the air-membranes, these waveguides offer a considerable operating range of ≈10 nm in the 1550 nm window. While the reduced index contrast weakens the perturbations due to surface roughness, we measure losses of 35±3dB/cm compared to 12±3 dB/cm for nominally identical air-membranes. Numerical analysis reveals that the difference in loss results from the different mode distribution and group index of the respective waveguide modes. Radius disorder is used as a fitting parameter in the numerical simulations with the best fits found for disorder levels of 1.4–1.7 nm RMS, which attest to the high quality of our structures.T.P. White is supported by the EU-FP6 Marie Curie Fellowship project “SLIPPRY”, L. O’Faolain is supported by the EU-FP6 Network of Excellence “ePIXnet” and J. Li was supported by the International Program Fund of 985 Project of Sun Yat-Sen University.© 2008 Optical Society of AmericaKeywords: Computer simulation; Crystal atomic structure; Laser optics; Monolithic integrated circuits; Numerical analysis; Optical properties; Optical waveguides; Organic polymers; Photonic crystals; Photonic devices; Photoresists; Powders; Refractive index; Silica200810.1364/OE.16.0170762016-06-14