Embedded progressive-three-layered fiber long-period gratings for respiratory monitoring

A long-period grating (LPG) was written into a progressive three-layered single-mode fiber that was embedded into a flexible platform as a curvature sensor. The spectral location and profile of the LPGs were unaltered after implantation in the platform. The curvature sensitivity was 3.747 nm m with a resolution of +/-1.1 x 10(-2) m(-1). The bend sensor is intended to be part of a respiratory monitoring system and was tested on a resuscitation training manikin.