Semiconductor Surface Emitting Laser Diodes

The conventional edge emitting laser diode uses either a single-stripe or multiple structure consisting of an active layer in a plane parallel to the semiconductor surface two cleaved facets, functioning as laser cavity mirrors, are perpendicular to this active layer. It is relatively difficult to fabricate and diagnose in situ, and only one-dimensional laser arrays have been monolithically fabricated. The surface emitting laser SEL, on the other hand, utilizes both surfaces of the wafer as laser mirrors and the light output is perpendicular to the wafer plane. This makes planar fabrication and diagnosis easier, and more importantly, allows for two-dimensional 2-D monolithic integration and array formation. This 2-D SEL array can be scale in number and size while maintaining a high filling factor. The SEL array diodes can also be individually addressed and controlled, and the output beam can also be individually addressed and controlled, and the output beam can also be easily accessed from both the front and back surfaces of the wafer. These features are very important and desirable when a large array of coherent emission semiconductor lasers is needed.