Optimization of the waveguide properties for ZnSe laser diodes

Abstract

We present numerical calculations to optimize the wave guiding properties of ZnSe based laser structures. Herein we not only focus on the actual waveguide layers but also on the problem of minimal cladding layer thickness. The latter is especially important for quaternary laser structures where p-type doping of the ZnMgSSe cladding layer is difficult. One of the ways to overcome this difficulty is the use of a p-type ZnSe buffer on top of the quaternary cladding layer. Our calculations show that this buffer layer has to be included in the optical design because it can severely deteriorate the wave guiding properties of the laser structure. The angular distribution of intensity in the far field pattern resulting from our calculations is compared to experimental data. This is shown to be a valuable tool to precisely determine the refractive index steps in actual devices.