FIELD ANALYSIS OF 2-DIMENSIONAL INTEGRATED OPTICAL GRATINGS

A method to determine the field scattered by a two-dimensional rectang ular grating of finite length is developed. Both periodic or aperiodic and lossy or lossless structures can be treated. The grating is built up as a finite sequence of two alternating types of waveguide section s connected by means of step discontinuities. The mode-matching method is employed to determine the field scattered by a single step. In com bining the scattering properties of the separate steps and waveguide s ections to describe the entire grating, the scattering matrix formalis m was employed. With the proposed method we have examined the 10- and the 20-period configurations described by Shigesawa and Tsuji [IEEE Tr ans. Microwave Theory Tech. 37, 3-14 (1989)] and by Liu and Chew [IEEE Trans. Microwave Theory Tech. 39, 422-430 (1991)], which show good ag reement. Furthermore, we have successfully extended these configuratio ns to gratings with 100 periods.