Multi-node wearable optical sensor based on microfiber Bragg gratings

Flexibly wearable sensors are widely applied in health monitoring and personalized therapy. Multiple-node sensing is essential for mastering the health condition holistically. In this work, we report a multi-node wearable optical sensor (MNWOS) based on the cascade of microfiber Bragg gratings (µFBG), which features the reflective operation mode and ultra-compact size, facilitating the functional integration in a flexible substrate pad. The MNWOS can realize multipoint monitoring on physical variables, such as temperature and pressure, in both static and dynamic modes. Furthermore, the eccentric package configuration endows the MNWOS with the discernibility of bending direction in addition to the bending angle sensing. The multi-parameter sensing is realized by solving the sensing matrix that represents different sensitivity regarding the bending and temperature between FBGs. The MNWOS offers great prospect for the development of human-machine interfaces and medical and health detection.