Humidity sensor fabricated by deposition of SnO2layers onto optical fibers

In this work, the fabrication and characterization of novel humidity sensors based on Lossy Mode Resonances (LMR) is presented. Tin oxide (SnO₂) coatings fabricated onto optical fibers are used as LMR supporting coatings. The SnO₂ based refractometers showed an average sensitivity of 6715 nm/refractive index unit (RIU) in the range 1.333–1.420 RIU. The behavior of this optical fiber device as relative humidity (RH) sensor was also tested, monitoring its response to different surrounding humidity levels. The results show a sensitivity of 0.1 nm/RH% in the range from 20% to 80% RH.