Transverse load and orientation measurement with multicore fiber Bragg gratings

We demonstrate the sensitivity of Bragg gratings in a multicore fiber to transverse load. The Bragg peaks are split because of stress-induced birefringence, the magnitude of which depends upon the load and grating position relative to the load axis. Experiments show that a set of gratings in a four-core fiber can measure a load axis angle to ±5(degree) and a load magnitude to ±15 N m-1 up to 2500 N m-1. We consider alternative designs of multicore fiber for optimal load sensing and compare experimental and modeled data.