Traveling-wave operation in a triangular-shaped monolithic semiconductor ring ridge laser

The traveling wave operation in triangular-shaped monolithic semiconductor ring ridge lasers is demonstrated, and their unique behavior and characteristics are described. A dry-etching process was used to fabricate triangular-shaped ring ridge lasers using thin-cladding graded index separate confinement heterostructure single quantum well material. The spectrum of a triangular ring ridge laser is shown. At threshold, the laser demonstrates multi-longitudinal-mode behavior. Above threshold, however, the device becomes single-longitudinal-mode, characteristic of a traveling wave laser. The horizontal far-fields for triangular ring lasers with 3.5 and 2.5 mu m wide ridges are shown. From these far-fields, it is evident that both bidirectional operation and unidirectional operation are possible.<>