long period fiber grating

In this letter, a novel shrinking long period fiber  grating(S-LPFG) is designed. This strain sensor is fabricated through mechanical polishing and arc-discharging, allowing for certain control over its sensitivity to strain. The single-mode fiber(SMF) is first preprocessed into a D-shaped fiber(DSF) through polishing. Then, a periodic melting-induced shrinking is applied to the fiber through arc-discharging modulation. The polishing and shrinking enhance the asymmetry of the single-mode fiber.