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Fabrication of high-aspect ratio photonic bandgap structures on silicon-on-insulator

Silicon-on-Insulator (SOI) is an attractive platform for fabrication of photonic bandgap devices. The large refractive index step between the silicon waveguide and the SiO2 lower cladding layer permits realization of periodic waveguides with very large index modulation. The large refractive index modulation is obtained by deep anisotropic etching into the silicon guide region, and makes it possible to obtain strong resonances in compact periodic structures with only a few periods. In addition, the processing of these structures is highly compatible with standard silicon CMOS processing. Hence this technology is attractive for low cost, highly integrated photonic and optoelectronic circuits.