title: Optical gain in GaAsBi/GaAs quantum well diode lasers.
abstract: Electrically pumped GaAsBi/GaAs quantum well lasers are a promising new class of near-infrared devices where, by use of the unusual band structure properties of GaAsBi alloys, it is possible to suppress the dominant energy-consuming Auger recombination and inter-valence band absorption loss mechanisms, which greatly impact upon the device performance. Suppression of these loss mechanisms promises to lead to highly efficient, uncooled operation of telecommunications lasers, making GaAsBi system a strong candidate for the development of next-generation semiconductor lasers. In this report we present the first experimentally measured optical gain, absorption and spontaneous emission spectra for GaAsBi-based quantum well laser structures. We determine internal optical losses of 10-15 cm(-1) and a peak modal gain of 24 cm(-1), corresponding to a material gain of approximately 1500 cm(-1) at a current density of 2 kA cm(-2). To complement the experimental studies, a theoretical analysis of the spontaneous emission and optical gain spectra is presented, using a model based upon a 12-band k.p Hamiltonian for GaAsBi alloys. The results of our theoretical calculations are in excellent quantitative agreement with the experimental data, and together provide a powerful predictive capability for use in the design and optimisation of high efficiency lasers in the infrared.
authors.affiliation: Advanced Technology Institute and Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom.
authors.forename: Igor P
authors.initials: IP
authors.lastname: Marko
authors.affiliation: Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1UB, United Kingdom.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Broderick
authors.affiliation: Advanced Technology Institute and Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom.
authors.forename: Shirong
authors.initials: S
authors.lastname: Jin
authors.affiliation: Materials Science Center and Faculty of Physics, Philipps-Universität Marburg, 35032 Marburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Ludewig
authors.affiliation: Materials Science Center and Faculty of Physics, Philipps-Universität Marburg, 35032 Marburg, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Stolz
authors.affiliation: Materials Science Center and Faculty of Physics, Philipps-Universität Marburg, 35032 Marburg, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Volz
authors.affiliation: Department of Electrical and Electronic Engineering, University of Bristol, Bristol BS8 1UB, United Kingdom.
authors.forename: Judy M
authors.initials: JM
authors.lastname: Rorison
authors.affiliation: Tyndall National Institute, Lee Maltings, Dyke Parade, Cork, Ireland.|Department of Physics, University College Cork, Cork, Ireland.
authors.forename: Eoin P
authors.initials: EP
authors.lastname: O'Reilly
authors.affiliation: Advanced Technology Institute and Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Sweeney