Sv. Burke, PLANAR WAVE-GUIDE ANALYSIS BY THE SPECTRAL INDEX METHOD .2. MULTIPLE LAYERS, OPTICAL GAIN AND LOSS, Optical and quantum electronics, 26(2), 1994, pp. 63-77
The most general form of the spectral index method is presented for th
e analysis of multiple-layered rib and related semiconductor waveguide
structures where the ribs have vertical sidewalls and are surrounded
by air. The model allows for the presence of loss or gain in any layer
and the generalization of the method to such complex problems is desc
ribed. A detailed account is provided on how to set up the transcenden
tal equation to solve problems for single ribs, and both symmetric and
asymmetric couplers. Finally, a polarization filter in the form of an
asymmetric coupler with one of its ribs capped with metal is analysed
numerically to illustrate the technique for a realistic design proble
m.