Polarization controlled vertical cavity surface emitting lasers

Summary form only given. The vertical-cavity surface-emitting laser (VCSEL) is considered as a key device for Gigabit LAN and optical parallel interconnects. For such high-speed data transmission, a completely single mode VCSEL in terms of transverse/longitudinal mode and polarization state is needed to avoid excess intensity noise and other instabilities. Most of VCSELs grown on [100] substrates show unstable polarization states due to isotropic material gain and symmetric cavity structures. Therefore, several methods for controlling polarization have been considered. On the other hand, the VCSEL grown on GaAs [311] substrate can provide a very stable polarization state. Single transverse mode and polarization mode controlled VCSELs by using [311]B substrate have recently been realized for aforementioned applications. In this paper, we review the technologies for polarization control of VCSELs and then will feature some characteristics of [311]B devices.