COUPLED-CAVITY RESONANT PHOTODETECTORS FOR HIGH-PERFORMANCE WAVELENGTH DEMULTIPLEXING APPLICATIONS

A new coupled-cavity resonant photodetector structure is studied to pr ovide a flat-topped passband with steep skirts in the photoresponse. T he idea is to add a low-loss cavity that is optically coupled to the a bsorptive cavity via an intermediate mirror. Experimental reflection s pectra confirm this coupling effect. Modeling for an InGaAs/GaAs/AlGaA s design reveals that this new coupled-cavity structure will be able t o show a 22 dB channel rejection ratio even when the optical channel s pacing is as narrow as 2 nm. In addition, the design and processing to lerances for cavity-mode adjustment are also addressed. (C) 1997 Ameri can Institute of Physics.