Vanadium Pentoxide (V2o5)-Based Optical Fiber Humidity Sensor with Linear Response and High Sensitivity

The objective of this study is to develop a highly responsive optical fiber relative humidity (RH) sensor using intensity modulation via evanescent wave (EW) that has a linear response across a broad dynamic range. For the sensor development, vanadium pentoxide (V2O5) doped sol–gel nanostructured thin film is coated on the centrally de-cladded section of a uniform and straight optical fiber. The sensor's response is characterized through extensive experimentation, demonstrating a sensitivity of 51.5 mV/% RH and a linear response range from 8 to 75% RH. The sensor has a fast response and recovery time of 0.2 s/%RH, making it ideal for use in various engineering and household applications that require measurements in the mid-RH range.