Spatio-Temporal High-Speed Modulation of Semiconductor Optoelectronics by Lateral Electric Fields

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

This proposal addresses fundamental physical issues impacting the growing area of integration of high-frequency electronics with optoelectronics and photonics. Our focus is the optical properties of semiconductors (quantum wells, wires, and dots) in the presence of strong dc and high-frequency (GHz-THz) electric fields. In particular, we will concentrate on cases where the high-frequency field is applied capacitively, i.e., it does not introduce additional carriers. The particular phenomena we will consider involve an interplay of ultrafast carrier dynamics in high-frequency fields, screening of the field by the spatial motions of the carrier distributions, propagation effects of the high-frequency field, and the interaction of the carrier distributions with light. Thus, the work will unite both micro and macroscopic length scales as well as dynamics on the femto to nanosecond timescales. Our effort will be primarily theoretical and computational. Together with our experimental collaborators, we will study the spatio-dynamics of carriers in photoconductors, semiconductor optical amplifier, and VCSEL's in the presence of the high-frequency fields. In the phenomena we will explore, the spatial aspects play a key role; on the one hand, we will be concerned with how such high-frequency fields adversely perturb the operation of optoelectronics and photonics, while on the other, we will explore potential phenomena for device applications. Potential applications include ultrahigh-bandwidth optical switching, enhanced photoconductive THz generation, ultrahigh-speed optical modulators, lateral mode control from semiconductor light emitters, and ultrahigh-speed beem steering.