Nanocomposite polyacrylamide based open cavity fiber Fabry-Perot humidity sensor

Area of Science:

• Optoelectronics
• Nanotechnology
• Sensor Technology

Background:

• Accurate humidity sensing is vital for environmental monitoring and industrial processes.
• Traditional humidity sensors often suffer from temperature-dependent errors.
• Fiber optic sensors offer advantages like remote sensing and immunity to electromagnetic interference.

Purpose of the Study:

• To propose and demonstrate a novel fiber optic humidity sensor with low temperature sensitivity.
• To utilize a polyacrylamide nanocomposite within a fiber Fabry-Perot interferometer for humidity detection.
• To characterize the sensor's performance across different relative humidity ranges.

Main Methods:

• Fabrication of a fiber Fabry-Perot interferometer by splicing a short single-mode fiber section between two larger offset single-mode fibers.
• Coating the interferometric cavity with a polyacrylamide nanocomposite hygrometer.
• Experimental characterization of the sensor's response to varying relative humidity levels.

Main Results:

• The developed sensor demonstrates humidity sensitivity of approximately 0.1 nm/(1% RH) in the 38%-78% RH range.
• A higher sensitivity of approximately 5.868 nm/(1% RH) was observed in the 88%-98% RH range.
• The sensor design inherently provides low temperature sensitivity, enhancing measurement accuracy.

Conclusions:

• A cost-effective and low-temperature-sensitive humidity sensor based on a fiber Fabry-Perot interferometer coated with polyacrylamide nanocomposite has been successfully demonstrated.
• The sensor's dual-range sensitivity makes it suitable for various humidity monitoring applications.
• This technology offers a promising alternative for precise environmental sensing.