Long-period grating fiber-optic sensors of bending for applications in pulmonology

Here we present a fiber-optic sensor of bending and demonstrate its application in monitoring of assisted breathing. The sensor is based on a long-period fiber grating and uses a simple monochromatic interrogation scheme. Here, we first explain the working principle of the sensor and then present a method for the measurement of respiratory volumes. The measurement is based on the correlation between a change in lung volume and the corresponding change in a local torso curvature. We validate the method by applying a calibration-test measurement procedure on a set of 15 healthy volunteers. Results show good sensor accuracy in measurements of the tidal and minute respiratory volumes for clinically relevant types of breathing. Finally, we compare the proposed method with the current clinical standards and competing techniques.