Paper
30 January 2012 Optical humidity sensor based on hollow core fiber
Author Affiliations +
Proceedings Volume 8351, Third Asia Pacific Optical Sensors Conference; 83510R (2012) https://doi.org/10.1117/12.915809
Event: Asia Pacific Optical Sensors Conference, 2012, Sydney, Australia
Abstract
We propose a novel relative humidity (RH) sensor based on hollow core fiber using direct absorption spectroscopic method in this paper. The wavelength scanning around water vapor absorption peak around 1368.59 nm is realized by injecting saw-tooth modulated current to a DFB laser diode. A reference signal is used as a zero absorption baseline and to help reduce the interference from DFB laser source and probed region. The humidity level is determined by the normalized voltage difference between reference signal and sensor signal at the peak of water vapor absorption. We demonstrate that a length of 5 cm hollow core fiber with a fixed small air gap between SMF and hollow core fiber as an opening achieves a humidity detection resolution of around 0.02%RH over the range 0 to 50%RH which does not require the use of any hygroscopic material.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
M. Y. Mohd Noor, N. Khalili, and G. D. Peng "Optical humidity sensor based on hollow core fiber", Proc. SPIE 8351, Third Asia Pacific Optical Sensors Conference, 83510R (30 January 2012); https://doi.org/10.1117/12.915809
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KEYWORDS
Humidity

Absorption

Sensors

Fiber optics sensors

Signal attenuation

Fiber lasers

Modulation

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