A breathing rate sensor with diaphragm-based Fabry-Perot interferometer

We present a new application of a diaphragm-based Fabry-Perot interferometer (FPI) sensor with a ultraviolet (UV) adhesive thin film for monitoring respiratory rate. Pressure sensing experiments show that the fiber-optic FPI sensor achieves a sensitivity of- 2.3 nm/kPa (0- 5 kPa) with temperature crosstalk of 0.14 kPa/degrees C, ensuring reliable performance. We propose a novel application for precisely measuring respiratory rate, inhalation duration and amplitude, as well as exhalation duration and amplitude, by monitoring the intensity response to pressure changes caused by breathing. This method offers a more convenient, compact, and costeffective approach for vital sign measurement. Results indicate that the sensor's respiratory rate measurements are consistent with those obtained from commercial physiological devices. Furthermore, by optimizing the sensor, heartbeat signals were also detected, suggesting that the proposed sensor is promising for long-term and non-invasive vital sign monitoring.