title: Numerically-assisted coupled-mode theory for silicon waveguide couplers and arrayed waveguides.
abstract: We investigate coupled-mode theory in designing high index contrast silicon-on-insulator waveguide couplers and arrayed waveguides. We develop and demonstrate a method of solution to the inverse problem of reconstructing the coupling matrix from the modal profiles obtained, in this case, from finite-difference frequency-domain field calculations. We show that whereas supermode theory provides a good approximation of the mode profiles, next-to-nearest-neighbor coupling becomes significant at small separation distances between arrayed waveguides. These distances are quantified for three different silicon-on-insulator material platforms. We also point out the phenomenon of field skewing and deformation at small separations.
authors.affiliation: University of California, San Diego, La Jolla, California 92093, USA. mlcooper@ucsd.edu
authors.forename: Michael L
authors.initials: ML
authors.lastname: Cooper
authors.forename: Shayan
authors.initials: S
authors.lastname: Mookherjea