TRANSVERSE-MODE CHARACTERISTICS OF VERTICAL CAVITY SURFACE-EMITTING LASERS

Transverse mode characteristics of vertical cavity surface-emitting (VC-SE) lasers are described. The mode structure is investigated as a function of the transverse dimension for proton-implanted gain-guided VC-SE lasers. A comparison is made to an air-post index-guided structure. The lasing modes and the evolution of the modes with increasing drive current for the VC-SE lasers are observed to be highly analogous to those of the edge-emitting lasers. Broad-area gain-guided lasers lase in the fundamental TEM00 mode near threshold. At higher currents, high-order modes are successively excited. A 5 μm square proton-implanted gain-guided VC-SE laser emits a single mode. On the other hand, an air-post index-guided SE laser, due to the large index difference between the laser and the cladding, emits multiple transverse modes. Moreover, we show that the gain-guided VC-SE lasers exhibit better device characteristics than the air-post index-guided lasers.