We report low densities of electrically active defects and low optical
losses at the wafer fused interface between InP and GaAs. Electron be
am induced current analysis shows electrically active defects with an
average spacing of 4.5 mum at the interface and significantly lower de
nsities 0.4 mum from the fused interface. Optical measurements of a Fa
bry-Perot resonator made by fusing an InP epilayer to a GaAs/AlAs mirr
or demonstrate a 3% increase in mirror transmission after fusing and n
egligible absorption at the fused interface. Based on these results, w
e present design considerations for fused surface emitting lasers.