Abstract: A dual beam laser incorporates a tapered layer within the optical cavity of a GaAs-AlGaAs double heterostructure laser. Dual output waveguides are therefore provided at one of the mirrors. By suitable variations of layer thickness and/or composition, the device operates either as a tapered power divider (TPD), branching the incident power of a single mode into the two output arms of the device, or as a tapered mode splitter (TMS), diverting different transverse modes into different arms. Because the different modes of the TMS have different thresholds, the laser can be pulsed with current pulses of different amplitude to control at which of the waveguides an output appears. The TPD, on the other hand, has coupled cavities which tend to suppress all but one dominant longitudinal mode. Also described is an integrated optical circuit embodiment of the TPD in which the resonator is formed by etched mirrors.

Abstract: An optical integrated circuit includes a double heterostructure (DH) junction laser and a DH detector formed on an underlying dielectric waveguide. Coupling from the laser to the waveguide and then into the detector is achieved by means of oblique crystal facets formed at the extremities of the laser and detector active regions by a two-step etching process. In the laser the oblique surfaces also provide sufficient optical feedback to define the laser resonator.