Integrable High-Performance Lasers by Impurity - Disordering.

Unique integrable lasers have been fabricated by impurity-induced disordering (IID). The lasers can be driven either from top to bottom as conventional lasers, or from top to top as top-driven lasers. The top-driven IID (TID) lasers are unique in that the carriers in the quantum well (QW) active layer are injected vertically from (instead of laterally between) the cladding layers. Because of this vertical injection nature, the threshold current of the lasers is essentially the same as that of the conventional IID lasers. The TID lasers have threshold current I _{rm th} = 2.0 mA and light output 19 mW with differential quantum efficiency eta_{rm d} = 38% per facet under RT CW operation. Both the threshold and the light output are the best ever reported for various kinds of top-driven lasers. The uniformity of the TID lasers is good due to the fact that the processing procedure of the TID lasers is considerably simpler than that of any other top-driven lasers yet reported. The study includes various aspects related to the integrable high-performance lasers: the design of the waveguide structure for maximum confinement factor, the optimization of the QW thickness and the QW stripe width and length for minimum threshold current, the technology for achieving impurity-induced disordering of the QW active layer, and the physics of the Si and Zn diffusion in heterostructure materials. Proposals on the integration of the laser with a FET or an optical modulator/detector have been presented.