High Sensitivity Force and Pressure Measurements Using Etched Singlemode Polymer Fiber Bragg Gratings

Singlemode polymer fiber Bragg gratings (FBGs) are etched down to a diameter of 30 μm to be used for high sensitivity tensile force measurements. The singlemode polymer fiber and the Bragg gratings are fabricated using the in-house fabrication facility. The fabricated cladding etched polymer FBGs are characterized for low value tensile force measurements and the sensitivity of the sensors is measured and compared with the theoretically estimated values. A sensitivity of 643 nm/N is obtained for the polymer Bragg grating with a diameter of 30 μm. A pressure sensor based on a singlemode polymer fiber grating is also demonstrated. Low pressure in the range of 290-790 Pa is measured and the observed sensitivity of the pressure sensor is 1.32 pm/Pa. Given the bio-compatible nature of polymer fibers, such as high sensitivity force and pressure sensors can find applications in bio-medical field where high sensitivity low value force/pressure measurements are required.