Fabrication of a Screw-Shaped Long-Period Fiber Grating for Refractive Index Sensing

Abstract

A process for femtosecond laser-based manufacturing was proposed to fabricate a long-period fiber grating (LPFG) with a screw shape. The screw-shaped LPFG was continuously inscribed by single laser scanning, which results in the improvement of fabrication time. For the single laser scanning, an optical fiber was traveled along fiber axis and rotated about the fiber axis. The 44.65-mm-long LPFG with a screw shape and the period of 450 mu m was fabricated about 17 min, and its sensitivity was 48 similar to 51 nm/RIU for the glycerin solutions. The proposed process enables us to produce the screw-shaped LPFGs with fast manufacturing time and reliable performance compared with the process with multi-path scanning.