Humidity Responsive Photonic Sensor based on a Carboxymethyl Cellulose Mechanical Actuator
Matthew R. Hartings, Kevin O. Douglass, Zeeshan Ahmed
We describe an intuitive and simple method for exploiting humidity driven volume changes in carboxymethyl cellulose (CMC) to fabricate a humidity responsive actuator on a glass fiber substrate. We optimize this platform to generate a photonic-based humidity sensor where CMC coated on a fiber optic containing a Fiber Bragg grating (FBG) actuates a mechanical strain in response to humidity changes. The humidity driven mechanical deformation of the FBG results in a large linear change in Bragg resonance over the humidity range of 5 %RH (relative humidity) to 40 %RH. The measurement uncertainty over this range is only ± 2 %RH.