Simultaneous Measurements of Strain and Temperature Using Long-period Fiber Grating Written on Twisted High-birefringence Photonic Crystal Fiber

Do Kyung Kim,Jihoon Kim,Min Seok Kim,Yong Wook Lee,Seul-Lee Lee,Sungwook Choi,Jinsil Han

doi:10.18494/sam.2020.2829

Abstract

Simultaneous Measurements of Strain and Temperature Using Long-period Fiber Grating Written on Twisted High-birefringence Photonic Crystal Fiber

Highlights

Over the past decade, fiber-optic sensors have demonstrated the potential for applications in a wide range of fields, such as structural health and environmental monitoring and biomedical instrumentation, owing to their merits of rapid response, compactness, durability, and immunity to electromagnetic interference, compared with conventional electronic sensors
To eliminate this cross sensitivity, numerous approaches have been suggested to realize separate measurements of strain and temperature.[14,15,16] Among these works, an long-period fiber grating (LPFG) written on a conventional high-birefringence fiber (HBF), designated as an HB-LPFG, provided an efficient and affordable solution to the simultaneous measurements of strain and temperature.[16]. It was possible to obtain two resonance dips with dissimilar cladding-mode orders, obtained at two orthogonal input polarization states (PSs) aligned along the principal axes of the HB-LPFG, i.e., slow and fast axes, within several tens of nanometers.[16]. The two resonance dips with different cladding-mode orders have different strain and temperature sensitivities as well
If an LPFG written on an high-birefringence photonic crystal fiber (HBPCF) is employed as a sensor head, the mechanical stability of the sensor can be improved because the elliptical core of the HBPCF creates a stronger birefringence than that of the conventional HBF (e.g., ~5.05 × 10–4),(16) which suppresses the mode coupling between orthogonal PSs, induced by macro- or microbending

Summary

Introduction

Fiber-optic sensors have demonstrated the potential for applications in a wide range of fields, such as structural health and environmental monitoring and biomedical instrumentation, owing to their merits of rapid response, compactness, durability, and immunity to electromagnetic interference, compared with conventional electronic sensors. The axial strain and temperature responses of these indicators of the fabricated THBPC-LPFG were investigated by applying independent strain and temperature variations (denoted by ∆S and ∆T) to the sensor head, respectively.

Results

Conclusion