Sol-Gel-Based Integrated Optical Microring Resonator Humidity Sensor

A novel humidity sensor based on sol-gel clad polymer microring resonator is presented. This sensor is based on the principle of change in refractive index of sol-gel on exposure to moisture. This change causes a shift in the resonant wavelength of the microring resonator. The performance of this sensor is analyzed and different ways of tailoring the sensor response are suggested. This sensor has a sensitivity of 16 pm/% relative humidity (RH) and a dynamic range up to 72% RH. The response time of this sensor can be tailored to be less than 200 ms, which could be utilized for monitoring human breathing condition in medical applications.