Analysis of a quantum well structure optical integrated device

Abstract

This paper demonstrates theoretical modeling of a quantum well structure optical integrated device. The constituent devices of the developed structure are a Quantum Well Infrared Photodetector (QWIP) to detect the optical infrared signal, a Heterojunction Phototransistor (HPT) to amplify the signal, and a Light Emitting Diode (LED) to emit this signal in a visible form. The model is based on the transient behavior of the constituent parts of the structure. The dominant pole approximation scheme is used to reduce its transfer function. The convolution theorem is used to get the overall transient response of the device under consideration. All interesting parameters concerning the transient response, rise time, output derivatives are theoretically investigated. The results show that the overall transient behavior, output derivative, and rise time of the considered structure are approximately the same as the constituent device possessing the lowest cutoff frequency. This type of model can be applied with high sensitivity in the up conversion of infrared or far infrared range for image signal processing.

Keywords

• quantum well infrared photodetector
• heterojunction phototransistor
• light emitting diode
• quantum well structure