Highly Coupled Seven-Core Fiber for Ratiometric Anti-Phase Sensing

A ratiometric fiber optic temperature sensor based on a highly coupled seven-core fiber (SCF) is proposed and experimentally demonstrated. A theoretical analysis of the SCF's sinusoidal spectral response in transmission configuration is presented. The proposed sensor comprises two SCF devices exhibiting anti-phase transmission spectra. Simple fabrication of the devices is shown by just splicing a segment of a 2 cm long SCF between two single-mode fibers (SMFs). The sensor proved to be robust against light source fluctuations, as a standard deviation of 0.2% was registered in the ratiometric measurements when the light source varied by 12%. Its low-cost detection system (two photodetectors) and the range of temperature detection (25 degrees C to 400 degrees C) make it a very attractive and promising device for real industrial applications.

Automated summary

This paper proposes a ratiometric fiber optic temperature sensor based on a highly coupled seven-core fiber (SCF), which is experimentally demonstrated. The sinusoidal spectral response of the SCF in transmission configuration is analyzed theoretically. The sensor consists of two SCF devices with anti-phase transmission spectra, and the devices are easily fabricated by splicing a 2 cm long SCF segment between two single-mode fibers (SMFs). The sensor shows robustness against light source fluctuations, with a standard deviation of 0.2% in the ratiometric measurements when the light source varies by 12%. Its low-cost detection system (two photodetectors) and wide temperature detection range (25 degrees C to 400 degrees C) make it a highly attractive and promising device for real industrial applications.