Room temperature pulsed oscillation of GaAlAs/GaAs surface emitting junction laser

Theoretical and experimental work has been done to reduce the threshold current density Jthof a GaAlAs/GaAs surface emitting junction laser emitting at a wavelength of 0.87 μm. The threshold current density Jthhas been obtained as a function of active layer thickness and the reflectivity of the mirrors. The necessary reflectivity for threshold is 95 percent in the case of m to achieve kA/cm²at room temperature. In order to realize this high reflectivity without deteriorating the p-side ohmic contact, we have proposed a new surface emitting laser structure with a ring electrode for the p-side contact. Room temperature pulsed oscillation has been realized. The minimum threshold current was about 310 mA at room temperature under pulsed condition. The corresponding Jthat the active layer is about 25 kA/cm². This indicates that we have realized the high reflectivity. The maximum light output peak power was more than 5 mW. The beam was as sharp as 10° (FWHM) and linearly polarized. A single longitudinal mode was observed against the temperature variation of 80 K. Fabrication processes and some lasing performances are described.