Accession Number : ADP007824

Title :   Low Field Electroabsorption and Self-Biased Self-Electrooptic Effect Device using Slightly Asymmetric Coupled Quantum Wells,

Corporate Author : AT AND T BELL LABS HOLMDEL NJ

Personal Author(s) : Goossen, K. W. ; Cunningham, J. E. ; Miller, D. A. B. ; Jan, W. Y. ; Lentine, A. L.

Report Date : 22 MAY 1992

Pagination or Media Count : 4

Abstract : Quantum wells and related layered semiconductor structures show strong electroabsorption that can be applied to make optical switches and modulators. Many different structures are possible, each with different electroabsorption characteristics. In addition to conventional rectangular wells, structures investigated include coupled wells, both symmetric and asymmetric, graded wells, low-barrier wells, and superlattices. The optimum structure depends to some extent on the application. Here we describe a novel, slightly asymmetric coupled well structure designed to operate at very low fields. The resulting operating fields are so low that we can make a self-biased symmetric self-electrooptic effect device(S-SEED); this is an opto-electronic switching device without a power supply, and this is the first demonstration of such a device suitable for use in two-dimensional arrays. For S-SEED operation, we want to use the lowest possible electric field so that we can minimize the switching energies. The optical switching energy is directly proportional to the field change required in switching; this is because all of the charge involved in charging and discharging the internal capacitance, C, of the device is photogenerated by absorption of the incoming light The charge required per unit area (and hence the required absorbed optical energy per unit area) is proportional to the field in the device. In addition, it is obviously important to minimize the operating voltage swing, V, to reduce the electrical energy, since this energy is about (1/2) CV2 for electrically driven modulators.

Descriptors :   *ELECTROOPTICS, *OPTICAL SWITCHING, *LIGHT MODULATORS, *QUANTUM ELECTRONICS, ABSORPTION, ARRAYS, BARRIERS, CAPACITANCE, DEMONSTRATIONS, ELECTRIC FIELDS, ELECTRIC POWER, ELECTRONIC SWITCHING, ELECTRONICS, ENERGY, INTERNAL, OPERATION, POWER SUPPLIES, SEEDS, SEMICONDUCTORS, STRUCTURES, SUPERLATTICES, SWITCHES, TWO DIMENSIONAL, VOLTAGE.

Subject Categories : Electrooptical and Optoelectronic Devices

Distribution Statement : APPROVED FOR PUBLIC RELEASE