Abstract

A new device is reported in this paper which incorporates a branching taper within the optical cavity of a GaAs double heterostructure (DH) injection laser as shown in Fig. 1. Dual output waveguides are therefore provided at one of the mirrors. The coupled cavities resulting from this configuration tend to suppress all but one dominant longitudinal mode. 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. We have achieved power ratios of between 4:1 and 5:1 for the TPD, oscillating in a dominant longitudinal mode at λ ≈ 8850 Å. For the TMS, a transverse mode at λ ≈ 8780 Å exits from one output arm of the device, while another transverse mode at λ ≈ 8550 Å is observed from the other; the relative intensity of these two output beams can be varied by changing the injection current.

© 1978 Optical Society of America