Validation of Fiber Optic-Based Fabry-Perot Interferometer for Simultaneous Heart Rate and Pulse Pressure Measurements

• Published in: IEEE sensors journal Vol. 21; no. 5; pp. 6195 - 6201
• Main Authors: Samartkit, Piyawat, Pullteap, Saroj, Seat, Han Cheng
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.03.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE); Institute of Electrical and Electronics Engineers
• Subjects: Applied geology; Arterial distension; Computer Science; Demodulation; Diffraction patterns; Earth Sciences; Engineering Sciences; Environmental Engineering; Environmental Sciences; Fabry-Perot interferometers; fiber Fabry-Perot interferometer; fiber optic sensor; Fiber optics; Geophysics; Heart rate; Interference fringes; Material properties; Materials; Mechanics; Micro and nanotechnologies; Microelectronics; Modeling and Simulation; Optical fiber sensors; Optical interferometry; Optical variables measurement; Optics; Optimization; Pattern analysis; Photonic; Plate theory; Pressure measurement; pulse pressure; Sciences of the Universe; Sensitivity; sensitivity characterization; Sensors; Thin films; Vibrations; blood pressure; Arterial distension; heart rate; fiber optic sensor; fiber Fabry-Perot interferometer; sensitivity characterization
• ISSN: 1530-437X; 1558-1748
• DOI: 10.1109/JSEN.2020.3041782

In this work, a fiber optic-based Fabry-Perot interferometer (FFPI) developed for simultaneous heart rate (HR) and pulse pressure (PP) measurement was investigated. Particularly, the FFPI was designed with simplicity in configuration for highly precise and non-invasive arterial distension measurement whose output was then demodulated via fringe counting to simultaneously obtain both HR and PP information through fringe pattern analysis and Kirchhoff-Love's plate theory, respectively. The sensitivity was then characterized by linear fitting of measured PP inducing a number of interference fringes, whose slope represented the FFPI sensitivity. Experiments were conducted both on a simulating device and healthy subjects, each measurement carried out at least 10 times. Obtained results demonstrated the FFPI sensitivity for PP measurement in both experiments to be ~1.916 mmHg/fringe. For HR measurements, an average difference of 1.24% was found when compared to a digital sphygmomanometer employed as reference. Analysis of the FFPI resolution revealed the impact of the fringe counting technique, interrogating wavelength, and sensing material properties on measurement accuracy. Consequently, the thickness of the transducing thin film was found to have the most impact on PP demodulation. Therefore, optimization of the aforementioned parameters could lead to the development of a more accurate FFPI for PP measurement.