Wearable side-polished fiber Bragg grating sensor for pulse wave and throat sound detection

Abstract

We demonstrate a flexible wearable optical fiber strain sensor using side-polished fiber Bragg grating (FBG) with a D-shaped polished zone of ∼54 μm depth and ∼15 mm length. The opto-mechanical response of the sensor embedded in a biocompatible polydimethylsiloxane elastomer is firstly investigated through various subtle wrist pulse tests. In comparison to a bare FBG, the developed sensor exhibits about two times of magnitude larger in time domain due to the more sensitive light-strain interaction with fiber gratings. Then along with the sound wave profiles of original audios, the extracted throat vibration signals validate the great potential of the sensor for wearable human speech detection.