Fabrication of Optical Stretchable Curvature Sensors With High Linearity

This article presents an optical approach for fabricating stretchable curvature sensors that possess a high degree of reproducibility, can detect diverse curvatures, and can accommodate large strain ranges, while also being cost-effective and straightforward. The method involves the removal of the cladding and core of a single-mode fiber via a side-polishing technique, followed by encapsulation in a PDMS film with hundreds of micros. The resulting structure permits multimode interference effects that enable the sensor to exhibit high linearity and minimal hysteresis in its sensitive and reversible detection of bending deformations. Additionally, the unique mechanical and sensing properties of the sensor make it well-suited for integration into clothing or placement on skin surfaces to monitor a range of human activities, from subtle physiological signals such as wrist pulses to extensive motions involving joint bending and hand gestures.