The methods for the transverse mode control and temperature characteristics improvement in 850 nm oxide confined vertical cavity surface emitting lasers (VCSELs) were investigated. For transverse mode control, dielectric aperture was demonstrated to suppress higher order modes. Substitution of AlAs for Al0.9Ga0.1As in partial bottom DBR was demonstrated to reduce thermal resistance of the devices and to enable operation in high temperature of 85.

A wavelength tunable surface emitting laser using a multiple quantum well as a tuning element is proposed. Wave-length can be tuned continuously in 150 Å for a tuner with the refractive index change ntu/ntu of 4%, the filling factor ξtu of 0.3 and without absorption loss. The actual tuning width is limited to be 3.5 Å with ntu/ntu of 0.43-0.15%, considering an absorption loss.