Analysis of Low-Reflection Facet Film for Semiconductor Optical Amplifiers Using Ablation Etching

Abstract

The reflectivity of a facet film for semiconductor optical amplifiers (SOAs) has been analyzed using laser ablation etching, which changes the ripple of spectrum light. We propose a method of estimating the optimum thicknesses of TiO 2 and SiO 2 layers by observing the change in reflectivity after ablation etching. We used this method to estimate the optimum thicknesses and reduce reflectivity, while bringing the thicknesses close to their optimum values. Ablation etching is a promising technique for analyzing facet reflectivity after facet coating.