Highly Sensitive Balloon-like Fiber Interferometer Based on Ethanol Coated for Temperature Measurement

Area of Science:

• Fiber optics
• Interferometry
• Sensor technology

Background:

• Mach-Zehnder interferometers are sensitive to changes in optical path length.
• Ethanol's refractive index is highly sensitive to temperature variations.
• Developing precise and cost-effective temperature sensors is crucial for various applications.

Purpose of the Study:

• To develop a highly sensitive, low-cost balloon-like fiber interferometer for temperature monitoring.
• To investigate the effect of sensitive length on refractive index (RI) detection performance.
• To evaluate the temperature sensitivity of the ethanol-filled interferometer.

Main Methods:

• Fabrication of a balloon-like structure using single-mode fiber within a Teflon tube.
• Filling the structure with ethanol solution via capillary action.
• Experimental investigation of RI detection performance with varying NaCl concentrations and sensitive lengths (10, 15, 20 mm).
• Measurement of temperature sensitivity in the range of 28.1 °C to 35 °C.

Main Results:

• The highest RI sensitivity of 212.88 nm/RIU was achieved with a 20 mm sensitive length.
• The ethanol-filled interferometer demonstrated a temperature sensitivity of 1.145 nm/°C.
• This sensitivity is 10.3 times greater than that of an unfilled structure (0.111 nm/°C).

Conclusions:

• The optimized 20 mm ethanol-filled balloon-like fiber interferometer exhibits high sensitivity and potential for precise temperature monitoring.
• The sensor's design offers advantages of low cost and ease of fabrication.
• This technology could be applied in applications requiring high-precision temperature measurements.