Adjustment of laser facet film reflectivity by ablation etching

We demonstrate reflectivity adjustment of a film-coated laser facet using ablation etching. The lasing is restrained by laser ablation etching of the facet film of a semiconductor laser and starts again with additional laser ablation etching. The laser ablation etching is useful not only for identifying more than /spl lambda//sub 0//(4n/sub film/) thickness of the coated film but also for adjusting facet coating thickness.