Fiber-tip optic sensor based on a three-beam interferometer for simultaneous measurement of flow rate and temperature

Area of Science:

• Microfluidics
• Optical Sensing
• Interferometry

Background:

• Accurate microfluidic flow rate monitoring is crucial for microfluidic chips.
• Optical flow rate sensors are often affected by microfluidic temperature variations.

Purpose of the Study:

• To develop a fiber-tip optical sensor for simultaneous measurement of microfluidic flow rate and temperature.
• To address the challenge of temperature interference in optical flow rate sensing.

Main Methods:

• A three-beam interferometer-based fiber-optic sensor was designed.
• The sensor utilizes UV adhesive and liquid paraffin in a hollow core fiber (HCF) microcavity.
• Changes in microfluidic flow alter air cavity pressure, affecting paraffin position and optical interference spectra.

Main Results:

• The sensor achieved a high flow rate sensitivity of -22.51 nm/(mm/s) within the 0.17 mm/s to 1.17 mm/s range.
• A stable temperature sensitivity of 13.513 nm/°C was demonstrated.
• Simultaneous measurement of flow rate and temperature was successfully achieved.

Conclusions:

• The developed sensor offers a low-cost platform for simultaneous measurement of physical parameters in microfluidic chips.
• This technology is significant for enhancing precision in on-chip biochemical reactions.
• The sensor overcomes temperature-related inaccuracies in optical flow rate measurements.