Surface emitting semiconductor lasers

A surface emitting laser is very attractive for lightwave communication as well as optoelectronics when taking advantage of the possible two-dimensional arrayed configuration. In this paper, the authors describe the research progress of developing a vertical cavity surface emitting (SE) injection laser based on GaAlAs/GaAs and GaInAsP/InP systems. Ultimate laser characteristics, device design, state-of-the-art performances, possible device improvement, and future prospects are also discussed. The authors proposed a vertical cavity surface emitting semiconductor laser and currently much work is done in our laboratory to realize it. In order to reduce the threshold current, they have improved the laser reflector and introduced a circular buried heterostructure. The microcavity structure, which is 7 μm long and 6 μm in diameter, was realized with a threshold of 6 mA. Thus, possibilities of an extremely low threshold current SE laser device and a densely packed two-dimensional array are suggested