Optical fibre Fabry-Pérot interferometer based on inline microcavities for salinity and temperature sensing

Area of Science:

• Photonics and Sensor Technology
• Materials Science
• Analytical Chemistry

Background:

• Accurate salinity monitoring is crucial for environmental and industrial applications.
• Existing sensor technologies may face limitations in sensitivity or simultaneous measurement capabilities.

Purpose of the Study:

• To develop and characterize highly sensitive optical fiber-based salinity sensors.
• To investigate sensor configurations for simultaneous salinity and temperature measurement.
• To achieve high sensitivity in salinity detection using optimized optical cavities and microfluidic integration.

Main Methods:

• Fabrication of Fabry-Pérot optical cavities using chemical etching and fusion splicing.
• Milling of microfluidic channels onto optical fibers using a focused ion beam.
• Spectral interrogation of sensor devices with a broadband light source.
• Implementation of Vernier-effect for enhanced sensitivity in dual-parameter sensing.

Main Results:

• Demonstrated optical fiber sensors with high sensitivity to salinity.
• Achieved salinity sensitivities up to 82.61 nm/M (6830.0 nm/RIU).
• Presented a sensor configuration leveraging the Vernier-effect for simultaneous salinity and temperature sensing.

Conclusions:

• The developed optical fiber sensors offer a promising platform for highly sensitive salinity detection.
• The integration of microfluidic channels and optimized optical cavities enhances sensor performance.
• The Vernier-effect configuration enables simultaneous and sensitive measurement of salinity and temperature.