Continuous arterial pulse wave monitoring using a fiber optic Fabry-Perot interferometer

• Published in: Measurement : journal of the International Measurement Confederation Vol. 257; p. 118755
• Main Authors: Pullteap, Saroj, Samartkit, Piyawat
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.01.2026
• Subjects: Fiber optic Fabry-Perot interferometer; Fiber optic sensors; Non-invasive heart rate measurement; Pulse wave monitoring; Quadrature phase demodulation; Fiber optic Fabry-Perot interferometer; Non-invasive heart rate measurement; Pulse wave monitoring; Quadrature phase demodulation; Fiber optic sensors
• ISSN: 0263-2241
• DOI: 10.1016/j.measurement.2025.118755

•Fiber optic Fabry-Perot interferometer (FFPI) is developed to monitor human pulse.•Quadrature phase demodulation allows pulse wave monitoring with high sensitivity.•High resolution in pulse wave characterization was investigated using FFPI system.•High fidelity human pulse waves were automatically obtained in quasi-real-time.•Proposed FFPI had validated high heart rate detection accuracy via standard device. In this work, a fiber optic Fabry–Perot interferometer (FFPI) was investigated for continuous pulse wave monitoring. The interferometer employs a laser modulation technique to generate a multiplexed interference output comprising two in-quadrature waves, enabling quasi-real-time and highly precise displacement measurement through a phase-shift demodulation technique. An FFPI pulse-sensing probe was accordingly designed with a diaphragm that deflects in response to arterial distension detectable at the skin surface. Initially, the sensing probe was characterized by measuring the displacement of a piezoelectric actuator. Subsequently, pulse wave monitoring was conducted on a human subject using a reference sphygmomanometer for preliminary validation. Characterization revealed an FFPI resolution of 1.32 nm at a velocity of 30 μm/s, demonstrating its high precision in displacement measurement and, by extension, in pulse wave monitoring. Additionally, the FFPI showed highly accurate heart rate detection, with a mean error ± standard deviation of –1.09 ± 0.94 beats per minute, based on 11 repeatable trials. Moreover, weak pulse waves from multiple unconventional pulse locations were successfully detected using the highly sensitive FFPI sensing probe. Therefore, the proposed high-precision FFPI system shows strong potential for development into a novel blood pressure monitoring tool for future biomedical applications.