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 degrees 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.