UC San Diego

Chip-scale photonic circuits promise to alleviate some fundamental physical barriers encountered in many areas of the life sciences and information technologies. This work investigates routes to miniaturization of chip-scale optical devices. Two new techniques and devices based thereon are introduced for the first time. One technique makes use of integrated metallic mirrors to construct reflectors which are by an order of magnitude smaller than their counterparts. Another technique is based on folding of chip-scale devices to fit long structures into small area on a chip. Although both techniques are demonstrated on some specific examples, the developed toolkit is applicable to a wide range of chip-scale devices including modulators, filters, channel add-drop multiplexers, detectors, and others. The major part of this Thesis focuses on miniaturization of waveguide reflectors and the devices based thereon. Fitting long waveguide Bragg gratings into a small area on a chip is demonstrated based on curved waveguide Bragg gratings; theory and analytical model of such structures is developed. In the second part of the Thesis, integrated metallic mirrors are proposed as reflectors with properties complementary to Bragg gratings - low polarization sensitivity, high reflectivity for different transverse modes, and good manufacturability. The feasibility of the proposed ideas is tested in both simulations and experiments. The demonstrated devices including biochemical sensors, micro-resonators, and inline filters are promising for applications in the life sciences and information technologies