Compact Optical Fiber Sensor Based on Silica Capillary Tube for Simultaneous High Temperature and Transverse Load Measurement

Jiewen Zheng,Bo Liu,Tutao Wang,Jianxin Ren,Lilong Zhao,Yaya Mao,Rahat Hllah

doi:10.1109/jphot.2021.3130572

Abstract

An optical fiber sensor is proposed and experimentally demonstrated for simultaneous measurement of high temperature and transverse load. The sensor is designed by splicing a silica capillary tube (SCT) to a single-mode fiber (SMF) and then heating the SCT to form an air bubble. SCT simultaneously functions as a Fabry Perot (F-P) microcavity and an anti-resonant reflection waveguide. These sensing mechanisms lead to high contrast sensitivity values of temperature and transverse load (1.89pm/°C,190.48pm/N and 24.93pm/°C, 16.68pm/N). Remarkably, the temperature sensitivity of this sensor is eleven times higher than that of the current fiber-tip micro-cavity (2.1 pm/°C). The sensor is also more advantageous in quantitative production and practical application due to its low cost, ease of fabrication, good mechanical strength, and convenient reflection probe.

Highlights

Due to its unique advantages such as high sensitivity, fast response, small size, easy manufacturing, and strong antielectromagnetic interference ability, optical fiber sensors have been widely studied and applied to the measurement of temperature [1], refractive index [2], magnetic field [3], and transverse load [4] in recent years
Type-II or regenerated FBGs fabricated with a femtosecond laser or ion beam etching have been reported to work well at high temperatures, their manufacturing efficiency is low at high costs [8,9]
The high-temperature transverse load sensor based on high birefringence fiber and a mode interferometer based on microstructure fiber were proposed [13,14,15]

Summary

INTRODUCTION

Due to its unique advantages such as high sensitivity, fast response, small size, easy manufacturing, and strong antielectromagnetic interference ability, optical fiber sensors have been widely studied and applied to the measurement of temperature [1], refractive index [2], magnetic field [3], and transverse load [4] in recent years. The fabrication and structure of these types of optical fiber sensors are both complex, limiting their large-scale production and application. These sensors have a characteristic size of at least a few millimeters, making them inconvenient for small areas and fixed-point measurements. We propose a reflective optical fiber sensor with high sensitivity for simultaneously measuring high temperature and transverse load. The phenomenon of the anti-resonant reflection waveguide is the envelope of the F-P interference edge in the reflection spectrum These sensing mechanisms lead to high contrast sensitivity values of temperature and transverse load (1.89pm/°C,190.48pm/N and 24.93pm/°C,16.68pm/N). Simple fabrication, solid structure, and a convenient reflection probe, among other features, make the sensor promising for practical application

FABRICATION AND PRINCIPLE

EXPERIMENT AND RESULT DISCUSSION

A1 A2 cos

CONCLUSION