Transverse waveguide design for high-brightness laser diodes

Abstract

We describe a new approach to achieving high brightness emission from laser diodes using a compound waveguide containing an unusual high order mode. This mode is predominantly single lobed and unusually localized in the low index region of the waveguide. To examine the utility of this mode we calculated the single-mode fiber butt coupling efficiency for an AlGaAs/GaAs compound waveguide of 61 micrometer aperture width, emitting at a wavelength of (lambda) equals 980 nm. Our results show a 2.3 times enhancement of the fiber coupling efficiency when compared with a simple broad area waveguide. Furthermore the coupling efficiency is still almost a factor of two greater than the coupling efficiency of the emission from a single mode ridge waveguide.