Fiber Optic Sensor Encapsulated In Polydimethylsiloxane For Heart Rate Monitoring

Technology fiber Bragg grating (FBG) belongs to the most widespread fiber optic sensors. It used for measuring a large number of chemical and physical quantities. Immunity to electromagnetic interference, small size, high sensitivity and principle information encoding about the measured value to the spectral characteristics cause usability of FBG sensors in medicine for monitoring vital signs such as heart rate, blood pressure, temperature or respiration. An important factor in this area is the use of an inert material for the Bragg gratings encapsulation. An interesting choice is the elastomer polydimethylsiloxane (PDMS). PDMS is optically clear, general inert, non-toxic and non-flammable. The material commonly used for biomedical and medical applications. Experimental results presented in this paper describe the creation of prototype FBG sensor for the heart rate monitoring of a human body. The sensor is realized by Bragg grating encapsulated into polydimethylsiloxane. The FBG sensor is part of the elastic contact strap which encircles the chest of the patient. This chest expansion leads to a spectral shift of the reflected light from the FBG. The research based on the monitoring of eight different test persons. Heart rate measurements were compared with a reference signal ECG and analyzed objectively by the Bland-Altman statistic.