The microgear is a microdisk resonator surrounded by a circular grating. The circular grating increases the modal selectivity of the cavity. In this paper, a two-dimensional (2-D) analytical method that describes the whispering-gallery mode (WGM) in a microgear resonator is presented. The model based on coupled mode theory needs the normalization of the WGM. In the past, some normalizations have been proposed; they all assume the mode to be bound, which is not true as WGMs are leaky modes. A new normalization with no approximation is presented. The numerical integration of the model is compared to 2-D finite-difference time-domain computations. It shows accurate computations of the resonant wavelength with lower numerical complexity. The method can be generalized to any deformation of the microdisk.
© 2005 Optical Society of America
(230.3120) Optical devices : Integrated optics devices
(230.5750) Optical devices : Resonators
(250.3140) Optoelectronics : Integrated optoelectronic circuits
(260.2110) Physical optics : Electromagnetic optics
Kien Phan Huy, Alain Morand, David Amans, and Pierre Benech, "Analytical study of the whispering-gallery mode in two-dimensional microgear cavity using coupled-mode theory," J. Opt. Soc. Am. B 22, 1793-1803 (2005)