Spatial mode control of VCSELs using micromirrors fabricated and replicated in semiconductor materials

Abstract

Summary form only given. Vertical cavity surface emitting lasers (VCSELs) are attractive as light sources due to their desirable properties such as circular mode profile, single longitudinal mode operation and an output orthogonal to the wafer surface. The spatial modes supported by the VCSEL are determined by a complex interplay between the current, thermal lensing, and spatial hole burning. The size of the VCSEL greatly influences these effects, and aperture diameters less than 5 /spl mu/m are typically required for single spatial mode operation. Consequently, the small overall gain volume of a single-mode cw VCSEL generally restricts it to a maximum power of only a few mW. In many applications, such as optical data storage and high-speed optical communication, high-power single-transverse mode is desirable. There have been several attempts to increase modal discrimination by spatial filtering. In this paper we demonstrate spatial mode control of VCSELs using micromirrors fabricated in gallium phosphide (GaP). Our approach is based on the idea of using an integrated micromirror for spatially filtering the VCSEL beam in the far-field.