Simultaneous refractive index and temperature measurements using a tapered bend-resistant fiber interferometer

Area of Science:

• Optics and Photonics
• Fiber Optic Sensing
• Materials Science

Background:

• Accurate measurement of refractive index (RI) and temperature is crucial for material characterization.
• Existing methods may face challenges in simultaneous, high-precision measurements.
• Fiber optic sensors offer advantages in sensitivity and remote sensing capabilities.

Purpose of the Study:

• To propose and experimentally validate a tapered bend-resistant fiber interferometer for simultaneous RI and temperature measurement.
• To demonstrate temperature-compensated RI determination of glycerol solutions.
• To achieve high accuracy in both temperature and RI measurements.

Main Methods:

• Utilizing a tapered bend-resistant fiber interferometer.
• Measuring differential phase shifts between inner and outer cladding modes.
• Analyzing mode responses to temperature and RI variations.

Main Results:

• Successfully demonstrated simultaneous measurement of RI and temperature.
• Determined temperature coefficients: -0.0253 rad/°C (inner) and -0.0523 rad/°C (outer).
• Determined RI coefficients: 4.0403 rad/RIU (inner) and 44.823 rad/RIU (outer).
• Achieved minimum errors of 0.6°C for temperature and 0.001 RIU for RI.

Conclusions:

• The proposed fiber interferometer is effective for simultaneous RI and temperature sensing.
• The method provides accurate, temperature-compensated RI measurements.
• This technique shows potential for advanced optical sensing applications.