Vertical cavity surface emitting lasers
The vertical cavity surface emitting laser (VCSEL) has a patterned mirror structure to enhance mode profile stability. The VCSEL, comprised of an active layer 3 between a pair of Bragg reflectors 2,4 has a top or emitting face contact 5 which substantially defines an emitting surface. A reflecting dielectric layer 6,8 is provided over a least a portion of the emitting surface to either enhance or suppress lasing action with the reflectivity value of the dielectric layer determining whether the lasing action is enhanced or suppressed. Active layer 3 may comprise one or more quantum wells.