Spatial-mode control of vertical-cavity lasers with micromirrors fabricated and replicated in semiconductor materials

Micromirrors were fabricated in gallium phosphide by mass transport to provide spatial-mode control of vertical-cavity surface-emitting lasers VCSEL’s!. The concave mirrors were used in an external-cavity configuration to provide spatial filtering in the far field. Single-mode cw lasing was demonstrated in 15-mm-diameter VCSEL’s with currents as high as 6 times threshold. The fabrication process was extended to micromirrors in gallium arsenide by use of a replication and dry-etch transfer process.