Highly sensitive quantum well infrared photodetectors

A fundamentally new method for light coupling in quantum well infrared phot odetectors that provides a ten-fold improvement over an optimized grating c oupler is presented. It is based on the prism-film coupler concept develope d earlier for selective mode coupling into integrated optical circuits. In this article this concept is specifically used to turn the incident electri c field from one that is polarized parallel to the quantum well layer to on e that is mostly perpendicular to the layer, thereby increasing dramaticall y the sensitivity of the quantum well infrared photodetector. Detailed samp le design and its computer simulation results are given and discussed. (C) 1999 American Institute of Physics. [S0021-8979(99)03517-3].