Measurement of refractive index change of optical fiber core induced by femtosecond laser scanning

Abstract

We report a new method to measure the refractive index change in optical fiber core induced by femtosecond (fs)laser exposure. An in-line Fabry-Perot interferometer, serving as the measurement platform, is constructed on a commercial single-mode optical fiber by one-step femtosecond (fs) laser fabrication. A positive refractive index change is observed and measured accurately as the laser pulse energy surpasses the ablation threshold.