Non-invasive Measurement of Vital Signs Based on Seven-core Fiber Interferometer

Electrical-based vital signs monitoring, especially the electrocardiogram (ECG) technique, has been investigated and applied in daily life. But this technique meets the limitations, e.g., the direct skin-contact, body hair shaving, the discomfort and inconvenience of the test subject. Recently, optical-based vital signs monitoring has been demonstrated to be a promising technique for realizing non-invasive monitoring. However, some of them exhibit the disadvantages of high cost and lacking compactness. We propose and demonstrate a non-invasive and continuous ballistocardiogram (BCG) based vital signs monitoring system, using a seven-core fiber interferometer (SCFI) sensor, which provided a more convenient, more compact, and less costly way to measure the vital signs. The results show that the measured HR and RR of the proposed sensor agree well with the commercial physiologic device. We recommend that the proposed sensor is promising for long-term and noninvasive measuring vital signs.