A planar waveguide concave grating employing dielectric mirrors

Abstract

Dielectric mirrors, which yield high-reflectances on grating facets, are proposed for the design of a planar waveguide concave grating. The transfer-matrix method is used to derive an expression for the reflectance of a series of air slots and high-index stacks. The Full-WAVE software, a finite difference time-domain EM solver from R-Soft, is used to evaluate the loss of the resulting 2D waveguide grating. The simulation results show that the polarization-dependent loss (PDL) is below 0.25 dB when the proposed dielectric mirror is used. The influence of the width variation of the dielectric stack is also taken into account. (C) 2007 Elsevier B.V. All rights reserved.