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

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 wit...