High-Sensitivity Refractive Index Sensor Based on Simply Fabricated Single Mode Fiber Tapers

A high sensitivity fiber-optic refractive index sensor based on the bi-conical single mode fiber tapers is proposed and demonstrated. The relationship between the resonance wavelength shift and surrounding refractive index is investigated. The experimental results show that the resonance wavelength linearly shifts toward longer wavelengths with the environmental refractive index ranging from 1.333 to 1.380. The response sensitivity increases with the decrease of the waist diameter of the tapered fiber. The proposed sensor is easily fabricated, compact and may be useful for the chemical and biotechnological industry.