Abstract

Multispectral tunable detectors based on intersubband transitions in quantum wells(QW’s) have been realized in the past in asymmetric wells with a step profile¹ or with graded barriers.^2,3 However, the responsivity largely depends on the wave-length. We propose a new device that combines the electrical tunability of a modulator and the constant responsivity of a detector biased at a constant voltage. As the modulator bias varies, its absorption peak shifts and scans the spectrum to be analyzed. Since the detector response is constant, spectrometry is performed. In the special case of a laser illumination, the detector response reaches a minimum value when the modulator absorbs at the photon energy.(QW’s) have been realized in the past in asymmetric wells with a step profile¹ or with graded barriers.^2,3 However, the responsivity largely depends on the wave-length. We propose a new device that combines the electrical tunability of a modulator and the constant responsivity of a detector biased at a constant voltage.

© 1993 Optical Society of America