Long-period gratings in photonic crystal fibers for sensing of external refractive index change and macro-bending

Abstract

Long-period gratings (LPGs) have been fabricated in endlessly single mode photonic crystal fibers (ESM-PCFs) utilizing focused CO 2 laser irradiation and residual stress relaxation technique. The responses of the ESM-PCF-LPGs to external refractive index and applied bending curvature have been investigated. As compared with the conventional fiber-based LPGs inscribed under the same condition, the ESM-PCF-LPGs exhibit higher sensitivity to external refractive index change and macro-bending, making them attractive candidates for chemical and biological sensing applications.