Stable Long-Period Grating in a Multimode Exposed-Core Fiber for High-Sensitivity Dual-Parameter Sensing
We report a dual-parameter optical fiber sensor based on a line-by-line femtosecond laser–inscribed long-period fiber grating (LPFG) in an exposed-core microstructured fiber (ECF). Owing to the large effective refractive index separation between guided mode groups in the ECF, stable and well-defined coupling from the f...