Optical fiber long-period grating humidity sensor with poly(ethylene oxide)/cobalt chloride coating

Maria Konstantaki; Stavros Pissadakis; Stergios Pispas; Nicholas Madamopoulos; Nikos A Vainos

doi:10.1364/ao.45.004567

Optical fiber long-period grating humidity sensor with poly(ethylene oxide)/cobalt chloride coating

Appl Opt. 2006 Jul 1;45(19):4567-71. doi: 10.1364/ao.45.004567.

Authors

Maria Konstantaki¹, Stavros Pissadakis, Stergios Pispas, Nicholas Madamopoulos, Nikos A Vainos

Affiliation

¹ Institute of Electronic Stucture and Laser, Foundation for Research and Technology-Hellas, Greece. mkonst@iesl.forth.gr

PMID: 16799666
DOI: 10.1364/ao.45.004567

Abstract

A long-period fiber grating (LPFG) humidity sensor is reported utilizing poly(ethylene oxide)/cobalt chloride (PEO/CoCl2) as a hybrid hygrosensitive cladding coating. A thin overlay of the material is deposited on the LPFG and with exposure to different ambient humidity levels, its spectral properties are modified. The material parameters associated with the sensing mechanism may include those of refractive index, absorption, and morphological alterations of the overlaid material. Relative humidity variations in the range from 50% to 95% have been detected with a resolution better than 0.2%. The response time constant of the fiber sensor is of the order of a few hundred milliseconds.