Abstract: This paper is aimed as a concise, short introduction to semiconductor lasers and a presentation of a specific method to improve optical gain. We start with the short description of lasers and semiconductor lasers, in particular. They play an important role in current technological developments. They found applications in many popular devices and communication systems, like laser printers, DVD players, optical fiber communications, to just name a few. In this paper, we outline fundamentals of semiconductor lasers and concentrate on those based on quantum wells. Properties and operating parameters of those devices can be optimized for a certain application. Here we concentrate on the influence of growth directions on optical gain. We summarized mathematical formalism used to determine band structure and gain and have conducted numerical simulations for various orientations of the crystal. We illustrate the applicability of our formalism by presenting results (band structure and material gain) for only few high symmetry orientations of the substrate and concentrate on quantum wells fabricated from InGaAsN/GaAs. Modifications of band structure due to rotations significantly affect material gain. Our approach can also be extended to other semiconductor materials. They can help to design lasers with improved characteristics.

Keywords: Semiconductor lasers, Band structure, Crystallographic orientation, Material gain.

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