Simultaneous measurement of curvature and temperature based on LP ₁₁ mode Bragg grating in seven-core fiber

Abstract

A robust and compact fiber sensor for simultaneous measurement of curvature and temperature based on LP11 mode Bragg grating is proposed and demonstrated in this paper. The sensor is formed by splicing a short piece of seven-core fiber (SCF) with Bragg grating to single mode fiber (SMF). The Bragg grating is inscribed by UV light exposure, and mainly LP01 resonance peak and LP11 resonance peak are observed in the reflection spectrum. The experimental results show that the wavelength of the LP11 Bragg resonance is insensitive to curvature but the power is very sensitive to curvature. The curvature sensitivity is −7.27 dB/m−1 with a linearity of 0.997 in the curvature range of 0–1 m−1. The temperature characteristic shows that the Bragg resonance has almost the same sensitivity as the common fiber Bragg grating (FBG). The sensor is also available to be independent of the ambient refractive index(RI).

Fiber-Optic Microstructure Sensors: A Review

“…The FBG based on the MCF is easier to achieve curvature measurement due to its performances of multi-dimension and the interaction between different cores. In [40], a robust fiber sensor was formed by splicing a short piece of seven-core fiber with the Bragg grating to the SMF for simultaneous measurement of curvature and temperature, as shown in Fig. 3 And its curvature sensitivity was -7.27 dB/m -1 with a linearity of 0.997 in the curvature range of 0 m -1 -1 m -1 and temperature sensitivity of 12 pm/ .…”

Sensitivity Enhancement of Curvature Fiber Sensor Based on Polymer-Coated Capillary Hollow-Core Fiber

“…Fiber optics sensors (FOS) are attractive to the scientific community and industry due to their intrinsic properties, such as small size, lightweight, corrosion resistance, immunity to electromagnetic interference, and high sensitivity. Several FOS have been assembled using specialty fibers such as photonic crystal fiber (PCF) [1,2], capillary hollow-core fiber (CHCF) [3], microfiber [4], D-shaped fiber [5], fiber Bragg grating (FBG) [6,7], long-period fiber grating (LPBG) [8], tilted fiber Bragg grating (TFBG) [9], and multicore optical fiber [10]. Recently, the fabrication of FOS using CHCF has been increased due to its easy fabrication and low-cost.…”

Strongly coupled multicore fiber with FBGs for multipoint and multiparameter sensing

“…Compared with other types of optical fiber, MCF comprises more than one core within the same cladding. Consequently, several identical or different sensors can be written at the same position along the length of the MCF, which is beneficial for simultaneous measurement of multiple parameters [14][15][16]. Therefore, multicore fiber Bragg grating (MCFBG) sensors have been proposed and successfully validated in a variety of mechanical parameters sensing, such as bending, twist, inclination, acceleration, or 3D shape sensing [17][18][19][20][21][22].…”