Theoretical analysis of transient behavior of optoelectronic integrated devices

Transient behavior of an optoelectronic integrated device composed of a heterojunction phototransistor and a light-emitting diode is studied theoretically. The transient behavior of the integrated device is investigated by considering: 1) the frequency response of a phototransistor and a light-emitting diode, and 2) the optical feedback inside the devices. The analytical expressions describing the transient response of the integrated device are derived, and the rise times in both the amplification and the switching modes also are calculated. By increasing the optical feedback, the rise time in the amplification mode is increased along with an increasing output, while that in the switching mode can be reduced effectively with a saturated output.<
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