Planar stripe with waist and/or notch (SWAN) injection laser

This paper describes a novel planar stripe-geometry injection laser (referred as SWAN laser) showing a single transverse and longitudinal mode operation made by a simple fabrication method. This stripe-geometry is composed of a main stripe section with the width of around 10 μm and mode control section with the nominal width near to carrier diffusion length, less than 5 μm, a shape of which looks like waist(s) and/or notch(es) along the stripe. A "kink", which often appears in the relation between a light output and a current in conventional planar injection lasers, is not observed at the power level of more than 20 mw/ facet. The laser has advantage of controlling modulation dynamics by the shape of waist(s) and/or notch(es) along the stripe that enables control of the lateral carrier diffusion profile in the vicinity of an active layer and the amount of spontaneous emission into laser mode.