Circular grating resonators as candidates for ultra-small photonic devices

Abstract

We investigate circular grating resonators (CGR) with a very small footprint. Photonic devices based on circular grating resonators are computationally designed, optimized and studied in their functionality using finite difference time-domain (FDTD) method. A wide variety of critical quantities such as transmission and reflection, resonant modes, resonant frequencies, and field patterns are calculated. Due to their computational size some of these calculations have to be performed on a supercomputer (e.g. parallel Blue Gene machine). The devices are fabricated in SOI using the computational design parameters. First they are defined by electron-beam lithography. Then the pattern transfer is achieved by an inductively coupled reactive-ion etch process. Finally, the devices are characterized by coupling light from a tunable laser with a tapered lensed fiber. As predicted from the simulations the measured transmission spectra exhibit a wide range of different type of resonances with quality factors exceeding 1000.