Relative humidity sensor based on polarization maintaining fiber loop mirror with polymer coating

A relative humidity sensor based on polarization maintaining fiber (PMF) loop mirror is presented. The proposed sensors are created through coating a thin layer of polyvinyl alcohol, whose refractive index varies as a function of humidity level, onto a PMF, from which a portion of the cladding is removed. The relative humidity optical fiber sensor is tested with different surrounding humidity level, showing a linear response to parameter. The sensitivity of the relative humidity measurement of 0.98 nm/%RH in the range from 20% to 85% RH is experimentally achieved. (c) 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:23642366, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27085