Mid-infrared quantum cascade laser waveguides with non-vertical sidewalls

The present paper provides a theoretical and experimental analysis of mid-infrared (4.5 mu m) quantum cascade laser Fabry-Perrot waveguides with various sidewall geometries. Calculations, processing and measurements have been carried out for varied sidewall angles of quantum cascade lasers, comparing the double trench ge-ometry (wet etched) with single ridge geometry (dry etched). The latter is shown to operate in the fundamental transverse mode and for larger waveguide widths. Furthermore, the optimum sidewall angle is shown to be about 64 degrees.

Automated summary

This study analyzes the theoretical and experimental aspects of mid-infrared quantum cascade laser Fabry-Perrot waveguides with various sidewall geometries. It compares the performance of wet etched double trench geometry with dry etched single ridge geometry at different sidewall angles, finding that the latter operates in the fundamental transverse mode for larger waveguide widths. The optimal sidewall angle is around 64 degrees.