ANALYSIS OF WAVE GUIDANCE BY SURFACE-RELIEF GRATING WAVE-GUIDES FOR OBLIQUE PROPAGATION

An analysis of wave guidance by surface-relief grating waveguides is p resented for the case of oblique propagation. This analysis is based o n the first-order differential equations expressing the coupling of th e space harmonics and an improved differential method is applied to so lve the equations in the grating region with arbitrary profile. The pr opagation constants are calculated for isotropic grating waveguides wi th sinusoidal profile and the calculated results indicate that the acc urate solutions can be obtained by increasing the number of expansion terms and the number of segments. Moreover, this method is extended to the case of the analysis of obliquely propagating waves and it is sho wn that peculiar leaky waves and stop bands appear owing to the coupli ng between TE and TM waves.