Point-by-Point Induced High Birefringence Polymer Optical Fiber Bragg Grating for Strain Measurement

In this paper, the first- and fourth-order fiber Bragg grating (FBG)-based axial strain sensors are proposed. The FBGs inscribed in step-index polymer optical fibers (POFs) (TOPAS core ZEONEX cladding) via point-by-point (PbP) direct-writing technique. A first-order FBG with a single peak is obtained pulse fluence of 7.16 J/cm2, showing sensitivity 1.17 pm/με. After that, seven peaks 1.81 J/cm2 between 1.249 pm/με 1.296 With higher 2.41 second five obtained, each which split into two due to high birefringence (Hi-Bi) ~5.4 × 10−4. present ~1.44 ~1.55 pm/με, respectively. difference corresponding Hi-Bi presents ~0.11 could potentially be used for simultaneous dual-parameter measurement, such as temperature strain.