GaAs lasers utilizing light propagation along curved junctions

A junction laser in which the light propagation within the device is along curved-junction paths is reported here. Path curvatures with radii ranging from 0.25 to 1.00 mm were obtained by the intentional introduction of curved diffused junctions. It was found that for radii of curvature smaller than a critical value of about 0.4 mm, the threshold-current density increases very rapidly. This value is in good agreement with the theoretical value, which is obtained by assuming that the gradient of the refractive index across the GaAs junction determines the minimum bending radius for low-loss propagation. The design of these curved-junction devices is critically dependent on the suppression of lasing along undesired junction paths perpendicular to the desired direction by bending these paths through a smaller than critical radius.