A fiber optic temperature sensor based on parallel dual Fabry-Pérot interferometers with Vernier-effect

Area of Science:

• Optoelectronics
• Fiber Optic Sensors
• Material Science

Background:

• Fabry-Pérot interferometers (FPIs) are widely used for sensing applications.
• Conventional FPI sensors often face limitations in sensitivity and stability.
• Polydimethylsiloxane (PDMS) offers unique thermo-optic properties suitable for temperature sensing.

Purpose of the Study:

• To propose and demonstrate a novel PDMS-optical fiber FPI temperature sensor.
• To leverage the Vernier effect for enhanced temperature sensitivity.
• To evaluate the sensor's performance in terms of sensitivity, linearity, and reversibility.

Main Methods:

• Fabrication of a compact FPI sensing probe using PDMS and single-mode fibers (SMFs).
• Construction of a reference probe using SMFs and hollow-core fiber (HCF).
• Exploitation of the Vernier effect by cascading two FPI cavities with slightly different free spectral ranges (FSRs).

Main Results:

• The proposed sensor achieved a high temperature sensitivity of approximately 21.54 nm/°C within the 25-30 °C range.
• Excellent linearity (>99.975%) and good temperature reversibility were observed.
• The Vernier effect significantly amplified the spectral shift, enhancing sensing sensitivity compared to conventional PDMS FPI sensors.

Conclusions:

• The PDMS-optical fiber FPI sensor based on the Vernier effect offers a promising solution for high-sensitivity temperature measurement.
• The compact design and enhanced sensitivity make it suitable for various demanding applications.
• Further development could lead to widespread adoption in industrial, medical, environmental, and aerospace fields.