Silicon subwavelength photonics: from fundamentals to applications in optical interconnects, spectroscopy and biological sensing

Recent advances in silicon photonics research at the National Research Council of Canada will be reviewed. A new type of microphotonic waveguides will be presented, exploiting the subwavelength grating (SWG) effect. The SWG technique [1] allows for engineering of the refractive index of a waveguide core over a range as broad as 1.5–3.5 simply by lithographic patterning using only two materials, for example Si and SiO2. Several examples of subwavelength grating waveguides and components implemented in silicon-on-insulator and operating at telecom wavelengths will be presented. These include waveguide crossings with minimal loss (<0.03 dB) and negligible crosstalk, fibre-chip edge couplers with a loss <1 dB, apodised surface grating couplers, high-performance MMI couplers, polarization rotators, athermal waveguides and planar waveguide multiplexers. Emerging applications in spectroscopy and biological sensing will be discussed.