A high sensitivity humidity sensor based on an Agarose coated photonic crystal fiber interferometer

Abstract

We report a novel high sensitivity relative humidity (RH) sensor based on Agarose coated photonic crystal fiber interferometer. We also demonstrate the experimental method to precisely apply a suitable coating thickness to achieve high RH sensitivity. The sensor shows a linear response for an RH change in the range of 40-70 %RH with a humidity resolution of 0.03 %RH and a higher humidity resolution of 0.01 %RH in the range 70-95 %RH. The sensor response is found to be reversible and repeatable with good long term stability.