Epitaxial Growth, Fabrication, and Performance of Ingaas Strained Quantum Well Laser Structures

Abstract

ABSTRACTThere is considerable interest in InGaAs/GaAs strained quantum well lasers for applications within the 0.9 to 1.1 μm wavelength range, such as high power lasers for Efdoped fiber amplifiers and rare-earth-ion solid state lasers, obtaining blue-green laser emission by frequency doubling, and optoelectronic integrated circuits. Epitaxial growth of these structures by organometallic vapor phase epitaxy, molecular beam epitaxy, and gas source molecular beam epitaxy will be discussed. The relative merits of AlGaAs and InGaP cladding layers will be examined with respect to growth challenges, laser processing and performance, and device reliability. Several device structures which provide transverse and lateral confinement will be reviewed. Reduction of the transverse far-field angle, which improves fiber coupling efficiency, can be accomplished through the use of periodic index separate confinement and depressed index cladding heterostructures. The performance of ridge waveguide lasers, which require accurate control of the ridge height, can be improved through the incorporation of etch-stop layers, either InGaP or AlAs, in the AlGaAs cladding layer. Nonplanar growth over mesas etched into the substrate is a convenient method to obtain buried heterostructure lasers. Carbon-doped planar InGaAs/AlGaAs lasers, using CC14 as an extrinsic dopant, have been fabricated with an impurity-induced layer disordering process. Microcylinder lasers have been fabricated out of InGaAs/InGaP layer structures.