Wearable Systems Based on Fiber Bragg Grating Sensors for Respiratory monitoring: Design, Fabrication, Open Challenges, and Future Directions

Wearable systems could be exploited to monitor physiological parameters in different scenarios, such as clinical settings, sports sciences, and occupational settings. Among many parameters, respiratory rate (RR) has a strong potential to provide helpful information on physiological status since it is sensitive to various stressors (both physical, physiological, and environmental). The use of fiber optic sensors, especially fiber Bragg grating (FBG) sensors, has recently gained broad interest in designing wearable systems for RR monitoring. The small size, the immunity from electromagnetic interferences, the high sensitivity, the fast response, the multiplexing capability, and the possibility to be incorporated into flexible matrices have allowed overcoming many of the historical concerns of wearable sensors in this scenario. In this study, we report the working principle of FBG sensors, how wearables based on these sensors can estimate RR, their main applications, and the main open challenges and opportunities.