Sensing Probe Development for Pulse Wave and Blood Pressure Detection using Fiber Optic Based Fabry-Perot Interferometer

A low-cost sensing probe based on fiber optic Fabry-Perot interferometer (FFPI) was designed and developed for pulse wave and blood pressure measurements. The FFPI system was comprised of the light source, sensing probe, and photodetector. To develop the sensing probe, four reflective materials and also three elastic materials were demonstrated to measure the reflectivity and elasticity, respectively. Furthermore, the probe was tested on the fingertip and neck to obtain the interference fringes with five times of repeatability. Besides, the peak detection and fringe counting techniques were employed to demodulate interference fringes into pulse waves. The results revealed that Aluminum-coated mirror provided the highest reflectivity, while a latex rubber balloon, the most elastic material, had a percentage of elongation of 199.25 mm and a Young's modulus of 2.85 MPa. To conclude, the sensing probe had the ability to detect heart pulses, paving the way for an affordable, painless, and user-friendly instrument.