Research on the Measurement of Heart Rate Based on LD Laser and Multimode Fiber

A micro-vibration fiber sensor for the measurement of human heart rate is proposed and experimentally demonstrated. The specklegram generated at the end of the multimode fiber depends on the applied disturbance along the fiber and thus can be used to detect the heartbeat signals. The sensitivity of vibration sensor based on fiber specklegram is highly sensitive to the multi-mode fiber diameters, which has been experimentally explored in this work. A multimode fiber with an appropriate diameter is selected to achieve a relative high sensitivity in vibration sensing. At last, the selected multimode fiber is utilized to measure the heart rate of the human body. By processing the detected specklegrams, a clear heartbeat signal curve is obtained, which shows potential application value in health monitoring.