Unconstrained pulse monitoring using a hetero-core optic fiber sensor

Abstract

In this paper, we proposed a hetero-core optic nerve pulse sensor made by softly silicone rubber sheet for unconstrained monitoring. An optical fiber has several advantages such as lightweight, minimal material, resistance to corrosion and electromagnetic interference. Additionally, a hetero-core optic fiber sensor is only sensitive to be bending action of the sensing portion and the transmission line is unaffected to external disturbance as pressure and temperature fluctuation because of its single-mode stable propagation scheme. Therefore, the hetero-core optic fiber sensor could be suitable for the pulse pressure sensing in unconstrained human activities and be placed in various sites such as a sofa and bath, and wearable device at the wrist. The proposed pulse sensor was devised to have high sensitivity by means of adding two spacers to the both ends of a hetero-core portion. Additionally, the pulse sensor was devised to have detectable area in the pulse pressure to be relatively wide with high sensitivity due to several hetero-core optic fiber sensors arranged in the pulse sensor. We successfully demonstrated to be adjustable to sensitivity and the sensing area, and some participants could detect the pulse signal due to a hetero-core optic nerve pulse sensor.