Abstract

Conventional gain-guided semiconductor injection lasers with contact stripes typically exhibit non-linearities in the light output power (P) vs. laser current (I) characteristics [1,2]. Such abrupt changes in the output characteristics known as kinks often occur at power levels of a few milliwatts for lasers with stripe widths on the order of 8 µm or greater. This phenomenon is now understood to result from spatial hole burning in the injected carrier profile which causes an instability that disposes the laser mode to shift laterally along the plane of the p-n junction. In the absence of a built-in mode guiding mechanism the lateral shift produces the kink [3-5]. As an alternative to a "built-in" waveguide it should also be possible to stabilize the mode laterally by coating the facet such that the modal reflectivity is relatively high at the center and decreases at the edges. Thus, even if as a result of spatial hole burning, a lateral mode would otherwise become unstable the higher central reflectivity serves to increases its stability and thereby increase the power level at which the kink occurs.

© 1980 Optical Society of America