Multimode Fabry⁻Perot Interferometer Probe Based on Vernier Effect for Enhanced Temperature Sensing.

Area of Science:

• Optical physics
• Sensor technology
• Materials science

Background:

• Miniaturized sensors for biological and medical applications require high resolution to detect subtle environmental changes.
• The Vernier effect offers a method to significantly enhance sensor sensitivity and resolution.

Purpose of the Study:

• To develop a miniaturized optical fiber Fabry-Perot interferometer (FPI) probe leveraging the Vernier effect for enhanced temperature sensing.
• To achieve a higher temperature resolution compared to conventional FPI sensors.

Main Methods:

• Fabrication of a silica FPI using focused ion beam milling on a tapered multimode fiber.
• Exploitation of multiple FPIs generated within the fiber cavity due to modal interference.
• Analysis of the reflection spectrum's Fast Fourier Transform (FFT) to identify components responsible for the Vernier effect.

Main Results:

• Demonstrated over 60-fold increase in temperature sensitivity compared to standard FPIs.
• Achieved a temperature sensitivity of -654 pm/°C within the 30 °C to 120 °C range.
• Attained an experimental temperature resolution of 0.14 °C.

Conclusions:

• The Vernier effect effectively enhances the sensitivity of optical fiber FPI probes for temperature sensing.
• The developed sensor demonstrates high resolution suitable for demanding biological and medical applications.
• The sensor exhibits stability, making it a promising candidate for practical implementation.