Low-loss, high reflectivity, first-order, pitch-by-pitch fiber Bragg grating fabrication in truly free-standing single-mode fiber

Abstract

Low-loss, high reflectivity, first-order fiber Bragg gratings are achieved by pitch-bypitch fabrication methodology in a truly free-standing fiber. Slit beam-profiling adopted attain transversely-extended index modification for each grating period defined by single laser pulse. Fiber Bragg grating of 0.52m period with >27dB transmission stopband and <0.2dB/cm insertion loss are demonstrated.