Flexible and Stretchable Photoelectric Dual-Mode Optic Fiber Sensors for Wrist Movement Monitoring

As a core sensing element for smart wearable devices, the application potential of flexible and stretchable optical fiber sensors is being rapidly explored. However, combining the unique deformation mechanical properties of stretchable optical fibers with multimodal sensing mechanisms remains a challenge. Herein, this work reports a flexible and stretchable dual-modal photoelectric optical fiber sensor. Its optical waveguide structure and conductive network are formed through a thermal drawing process and metal target sputtering technology, respectively, integrating the dual-modal photoelectric sensing mechanisms onto a single fiber to achieve a dual-channel photoelectric response. Furthermore, the tensile deformation of the sensor exhibits good sensing response and high linear correlation (R2 > 99) for both optical and electrical signals, and there is a strong correlation relationship between the two signals. As a proof-of-concept, the application of the sensor in wrist basic motion patterns was demonstrated. By leveraging the complementary mechanisms of the dual-modal signals, wrist motion processes were effectively detected and distinguished. This work not only provides a practical route for dual-modal photoelectric sensing in stretchable optical fibers but also showcases their practical applications in wrist activity monitoring.