Investigation of Bending Sensor based on No-core Optical Fiber Coated and Uncoated PDMS

This research focused on the no-core fiber (NCF) as a bending sensor. The proposed sensor was made of a Polydimethylsiloxane (PDMS)-coated cascaded SMF-NCF-SMF (SNS) structure using the molding technique. The modal interference mechanism was created by splicing the NCF with a single mode fiber (SMF) pigtail. The linearity and sensitivity performance of the uncoated and coated NCF sensors with the length of 3 cm and 3.5 cm were compared in this research. The proposed PDMS-coated sensor with length of 3 cm has achieved the highest sensitivity of 2.3291 nm/m(-1), which is approximately 1.7 times greater than the uncoated NCF sensor of the same length. The proposed sensor has a high curvature sensitivity and a large curvature detection range, making it a potential bending sensor for a variety of applications that require precise and versatile detection of bending deformations.