We derive the coupled equations for the ideal modes of an optical waveguide, using a Green function technique, and use these to determine the TM–TM coupling coefficient for a periodic waveguide diffraction grating. The results are consistent with experimental observations, in marked contrast to the results of more conventional versions of the ideal mode expansion. Further, our approach can deal with more general corrugated structures than can easily be done with other methods.
© 1990 Optical Society of America
Original Manuscript: May 30, 1989
Manuscript Accepted: December 1, 1989
Published: April 1, 1990
C. Martijn de Sterke and J. E. Sipe, "Ideal mode expansion for planar optical waveguides: application to the TM–TM coupling coefficient for grating structures," J. Opt. Soc. Am. A 7, 636-645 (1990)