Simple approach to coupling in textured planar waveguides.
We develop a self-consistent Green's function technique to calculate the full photonic band structure for guided modes in slab waveguides that have been textured in one dimension with a thin surface grating. The technique is conceptually simple and can easily be reduced to an eigenvalue problem by use of approximations similar to those used in conventional coupled-mode theories. We show that this approach yields the correct TM-TM coupling coefficient at oblique incidence and provides a transparent interpretation for its vanishing at a critical angle.
Paddon
P
P
Advanced Materials and Process Engineering Laboratory, Department of Physics and Astronomy, 2355 East Mall, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
Young
J F
JF