Achievement

James Ferrara developed a process for fabricating novel hollow-core waveguide design based on High Contrast Gratings (HCGs), subwavelength gratings made from high refractive index material (e.g. silicon). HCGs have sub-micron features and guide light at communications wavelengths (1.55um). Waveguides with high phase dispersion are very beneficial for applications involving group velocity manipulation, e.g., delay lines, interferometers and optical switches. However, as many of these waveguides involve exotic nanoscale designs, the ease of fabrication is often an issue. HCGs, when properly designed, can be excellent broadband mirrors, providing reflectivity at least as high and as broadband as a 40 layer DBR stack. Guiding light between two parallel HCGs can reduce the waveguide loss to unprecedented levels of 0.006dB/m. His research team has demonstrated novel in-plane lateral guiding with these devices. This is the first time this counter-intuitive phenomenon has been demonstrated.