An Investigation of the Fundamental Physical Processes in Quantum Dots Impacting Semiconductor Lasers

University Of New Mexico, Albuquerque NM

Investigators

Abstract

This project, which will be conducted by the Center for High Technology Materials at the University of New Mexico, will investigate the basic physics of quantum dot (QD) materials that influence the performance of semiconductor lasers in the 1.3-1.6 micron wavelength range. An advanced theoretical model of the QD will be employed to determine the bound states in single, adjacent, and stacked QDs. This information will be subsequently used to determine precisely the transition matrix elements required for gain and spontaneous emission computations. The theoretical knowledge will be tested against the experimental component of the program, which will investigate carrier capture by the quantum dot, gain, and homogeneous broadening. Our acquired expertise will enable the design, fabrication, and optical characterization of external cavity lasers that can be tuned over a 250 nm range with threshold current densities of less than 1 kA/cm^2, ultra-low-chirp optical devices for telecommunications, and filament-free lasing in broad area devices. Tunable semiconductor lasers from 1.4-1.6 micron are particularly attractive as the need for greater bandwidth in fiber-optic communications is increasing dramatically. Theoretical studies indicate that the elimination of filaments and chirp in QD lasers is possible because of the QD's exceptionally low linewidth enhancement factor. The impact of this project will be most significant at the telecommunications wavelengths of 1.3-mm and 1.55-mm and at "eye-safe" wavelengths operating above 1.4 mm.