ION-BEAM-ETCHED LASER FACETS FOR INP-BASED LASERS

In this paper laser facets are produced by ion beam etching (IBE) for the first time using mixtures of nitrogen and oxygen, The effects of d ifferent imperfections of etched facets on the optical reflectivity ar e investigated, Broad area lasers with both facets cleaved and lasers with one etched and one cleaved facet are fabricated emitting at a wav elength lambda = 1.55 mu m. The reflectivity of the etched facet is ex tracted from threshold current measurements. With known reflectivity, the increase of threshold current can be calculated for different reso nator dimensions. Although the geometrical requirements for good quali ty etched laser facets are fulfilled, the reflectivity is still somewh at lower than for cleaved facets, Nevertheless, the expected increase of threshold current for a typical laser structure is only 1.7 mA per facet. The increase is caused by the formation of an antireflection la yer, formed by backsputtering.