Design, Fabrication, Characterization, and Application of an Ultra-High Temperature 6H-SiC Sapphire Fiber Optic Vibration Sensor

Yigang Huang,Fei Tang,Dawei Ma,Zhenjun Liu,Xiaohao Wang

doi:10.1109/jphot.2019.2926297

Abstract

A 6H-SiC Sapphire fiber optic vibration sensor that can work at 1200 °C was designed, fabricated and tested in this paper. A sapphire fiber and a 6H-SiC vibration-sensitive element constituted the Fabry-Perot resonant cavity. The laser was input via the sapphire fiber, enabling the vibration signal to be converted to an optical signal through the Fabry-Perot cavity, and the vibration parameters were obtained by optical demodulation. The vibration-sensitive element consisted of a cantilever structure, whose structure parameters were determined by the combination of theoretical analysis and simulation. A nanosecond laser was employed to fabricate the 6H-SiC vibration-sensitive element to improve the processing efficiency and simplicity. The sensor was tested from room temperature to 1200 °C. The results showed that its frequency measurement sensitivity remains 0.9997 Hz/Hz from room temperature to 1200 °C, with the full-scale precision being 0.44% F.S. The sensor's output voltage is linearly correlated with the vibration acceleration from ambient temperature to 800 °C, making the acceleration measurement sensitivity 17.86 mV/g at 800 °C. The maximum frequency measurement error was 4.72 Hz when the sensor was at the field application of high temperature casting.

Highlights

Vibration measurement and analysis is an important topic in numerous fields such as structural engineering, acoustics, biotechnology, entertainment equipment, and security monitoring [1]
A 6H-Silicon carbide (SiC) Sapphire fiber optic vibration sensor that can work at 1200 °C was designed, fabricated and tested in this paper
The laser was input via the sapphire fiber, enabling the vibration signal to be converted to an optical signal through the Fabry–Perot cavity, and the vibration parameters were obtained by optical demodulation

Summary

Introduction

Vibration measurement and analysis is an important topic in numerous fields such as structural engineering, acoustics, biotechnology, entertainment equipment, and security monitoring [1]. Fiber optic sensors based on optical signal transmission are highly sensitive and can effectively solve the high temperature bonding failure of traditional electronic sensors, and bring advantages such as corrosion resistance and anti-electromagnetic interference [9]–[11]. They are deemed by many researchers to be the best solution of obtaining measured data in severe environments [12]. Among all the fiber optic sensors, the optical fiber Fabry–Perot interferometer sensor is the most attractive, thanks to its simple principle, structure, small size etc. [13]–[15]

Methods

Discussion

Conclusion