Abstract

Gratings are a key element of present optoelectronic devices. They are used as tunable optical filters for semiconductor optical switches and photodetectors and contradirectional or codirectional couplers [1, 2], which for instance are often used in DBR and DFB laser systems [3], Efficient tools are necessary for the design of waveguide grating devices. A variety of approaches have been investigated. The Coupled Mode Theory (CMT) [4], the Mode-Matching Transfer Matrix Method (TMM) [5] based on a field expansion in terms of modes, and rigorous numerical methods as Finite-Difference time domain algorithms [6-8] and bidirectional beam propagation methods [9-11], The following parameters have to be considered for a useful comparison: 3 dB bandwidths of the filter characteristics, reflectivity at the transmission wavelength and the transmission spectra considering radiation and guided fields. In the following all the above named methods are compared. Only Finite-Difference time domain algorithms yield accurate results.

© 1995 Optical Society of America