Current status of epitaxial 1.31-1.55 /spl mu/m VCSELs on InP

We have reviewed the recent research carried out to realize all-epitaxial VCSELs at long wavelengths. Shortcomings of the InP materials system were overcome by the use of AsSb-based alloys for DBRs and multiple active regions to combat low gain materials. The inclusion of InP spreading layers was seen to greatly improve the thermal properties of the devices. Two apertures were developed for the optical and current confinement. Careful placement of these apertures is expected to improve the VCSEL performance considerably.