InGaSn-assisted in-fiber Fabry-Perot temperature sensor with ultra-high sensitivity

Area of Science:

• Optics and Photonics
• Materials Science
• Sensor Technology

Background:

• Fiber optic sensors are crucial for remote and precise measurements.
• Fabry-Perot interferometers (FPIs) offer a versatile platform for sensing applications.
• Existing extrinsic FPIs often lack the sensitivity required for delicate biological or pharmaceutical environments.

Purpose of the Study:

• To develop a highly sensitive in-fiber temperature sensor.
• To utilize the unique properties of Indium gallium stannum (InGaSn) liquid metal for enhanced thermal detection.
• To investigate the sensor's performance and potential applications in biopharmaceutical fields.

Main Methods:

• Fabrication of an in-fiber Fabry-Perot interferometer (FPI) by splicing a single-mode fiber with hollow-core fibers (HCFs).
• Filling the FPI cavity with Indium gallium stannum (InGaSn) alloy, a liquid metal with high thermal expansivity.
• Characterizing the sensor's spectral response to temperature variations and analyzing the influence of HCF inner diameter and liquid metal volume.

Main Results:

• The proposed InGaSn-filled in-fiber FPI sensor demonstrated a high temperature sensitivity of 11.3 nm/°C within the 30-40°C range.
• This sensitivity is approximately an order of magnitude higher than conventional extrinsic FPI sensors.
• The study analyzed the impact of structural parameters, such as HCF inner diameter and liquid metal filling, on sensor performance.

Conclusions:

• The developed in-fiber liquid metal FPI sensor offers superior temperature sensitivity.
• Its high performance makes it suitable for critical temperature monitoring in in-vitro cell culture and biopharmaceutical applications.
• Further optimization based on structural parameters can enhance its applicability in specialized fields.