Circular grating resonators as nano-photonic modulators

Abstract

Circular grating resonators could lead to the development of very advanced silicon-on-insulator (SOI) based nano-photonic devices clearly beyond state of the art in terms of functionality, size, speed, cost, and integration density. The photonic devices based on the circular grating resonators are computationally designed and studied in their functionality using finite-difference time-domain (FDTD) method. A wide variety of critical quantities such as transmission and field patterns are calculated. Due to their computational size some of these calculations have to be performed on a supercomputer like a massive parallel Blue Gene machine. Using the computational design parameters the devices are fabricated on SOI substrates consisting of a buried oxide layer and a 340-nm-thick device layer. The devices are defined by electron-beam lithography and the pattern transfer is achieved in a inductively coupled reactive-ion etch process. Then the devices are characterized by coupling light in from a tunable laser with a lensed fiber. As predicted the measured transmission spectra exhibit a wide range of different type of resonances with Q-factors over 1000 which compares very well with the computations.