Wearable pulse monitoring system for evaluating cardiovascular parameters based on tapered no-core fiber

We developed a highly sensitive tapered no-core fiber (TNCF)-based cardiovascular monitoring system featuring a glycerol-filled polydimethylsiloxane (PDMS) sac design that minimizes alignment errors. The system achieves 0.339 dB/kPa vibration sensitivity, 0.17 kPa resolution, and 6.1/6.4 ms response/recovery times while maintaining excellent stability. It enables comprehensive vascular health assessment through: 1) pulse wave velocity measurement via synchronized chest-wrist waveform acquisition, 2) heart rate monitoring during rest/exercise, and 3) blood pressure prediction using random forest regression. The regression model is evaluated as follows: correlation coefficients of 0.95 and 0.94 for systolic blood pressure and diastolic blood pressure, mean absolute relative differences of 1.45% and 1.49%, and errors of 0.41 ± 1.98 mmHg and 0.08 ± 1.44 mmHg, respectively, compared with standard sphygmomanometric measurements.