Humidity-insensitive optical fibers for distributed sensing applications.

Area of Science:

• Materials Science
• Optical Engineering
• Sensor Technology

Background:

• Humidity significantly impacts environmental monitoring applications.
• Thermo-hygrometer fiber sensors require humidity-resistant temperature references to prevent cross-sensitivities.
• Existing optical fibers may exhibit humidity-induced cross-sensitivities, affecting sensor accuracy.

Purpose of the Study:

• To develop and present innovative optical fibers with enhanced humidity insensitivity.
• To ensure reliable temperature referencing in fiber optic sensors across a wide temperature range.
• To address the challenge of cross-sensitivity in humidity and temperature measurements.

Main Methods:

• Two novel standard-size optical fibers coated with acrylate and silicone were fabricated.
• The optical fibers were tested for humidity insensitivity under controlled conditions.
• An optical time-domain reflectometer (OTDR) sensor utilizing Rayleigh scattering was employed for testing.

Main Results:

• The developed optical fibers demonstrated insensitivity to humidity across temperatures from -20°C to 55°C.
• The OTDR sensor achieved meter-range resolution over kilometer-long fiber spans.
• The sensor system exhibited a response time of only a few minutes.

Conclusions:

• The novel optical fibers offer a robust solution for humidity-insensitive temperature sensing.
• These fibers are suitable for applications requiring precise temperature monitoring in humid environments.
• The developed sensor technology provides high resolution and fast response times for long-distance measurements.