Stable broad near-field (single lateral mode) semiconductor laser

Abstract

Single stripe gain-guided semiconductor lasers are generally fabricated with a stripe width limited to about 3 μm to obtain single lateral mode operation. For lasers with larger stripe widths, the carriers under the stripe induce index antiguiding that leads to near field instability. This paper presents a V-grooved stripe contact structure that preferentially channels the carrier to the centre of the stripe as well as maintaining a stable carrier distribution induced by the V-groove contact. Such a laser has been successfully fabricated by liquid phase epitaxy and is able to emit in a single lateral mode with a FWHP of 20 μm at up to two times threshold current. The GaAIAs laser typically has an active layer of 0.1 μm, cladding layer thicknesses of 3 μm and a p-GaAs cap layer, 6 μm thick, with a flat-bottom V-groove etched into it. Power output of 20 mW is measured for this prototype.