Fig. 2
From: Automatic and continuous blood pressure monitoring via an optical-fiber-sensor-assisted smartwatch
The characteristics of the optical fiber sensor. a The sensor’s optical power-pressure curve, which ranges from 0–8 kPa. b Study of sensitivity coincidence over 5 cycles. c 70,000 cycles of cyclic loading at a frequency of 2 Hz are applied to the sensor. d Response time of the sensor. e The sensing area with sixteen grids on the wrist. f Arterial pulse signals from various sites by proposed sensor