Abstract

The phenomenon of evanescent-wave scattering (EWS) is used to design an optical-fiber humidity sensor. Porous solgel silica (PSGS) coated on the surface of a silica optical-fiber core scatters evanescent waves that penetrate the coating layer. Water molecules in the gas phase surrounding the optical fiber can be absorbed into the inner surface of the pores of the porous silica. The absorbed water molecules form a thin layer of liquid water on the inner surface of the porous silica and enhance the EWS. The amount of water absorbed into the PSGS coating is in dynamic equilibrium with the water-vapor pressure in the gas phase. Therefore the humidity in the air can be quantitatively determined with fiber-optic EWS caused by the PSGS coating. The humidity sensor reported here is fast in response, reversible, and has a wide dynamic range. The possible interference caused by EWS to an optical-fiber gas sensor with a reagent-doped PSGS coating as a transducer is also discussed.

© 2004 Optical Society of America

Full Article  |  PDF Article
More Like This
Porous solgel fiber as a transducer for highly sensitive chemical sensing

Shiquan Tao, Christopher B. Winstead, Jagdish P. Singh, and Rajeev Jindal
Opt. Lett. 27(16) 1382-1384 (2002)

Fiber optic evanescent wave humidity sensor based on SiO2/TiO2 bilayer films

Xixi Huang, Min Lai, Ziming Zhao, Yang Yang, Jinze Li, Huatang Song, Jixiang He, Yan Ma, and Bo Liu
Appl. Opt. 60(8) 2158-2165 (2021)

Relative humidity sensor with optical fiber Bragg gratings

Pascal Kronenberg, Pramod K. Rastogi, Philippe Giaccari, and Hans G. Limberger
Opt. Lett. 27(16) 1385-1387 (2002)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Figures (4)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Metrics