Dual-core optical fibre ups data processing, sensing
"Nanomechanical optical fibres do not just transmit light like previous optical fibres," stated Wei H. Loh, deputy director of the EPSRC Centre for Innovative Manufacturing in Photonics and researcher at the Optoelectronics Research Centre, at the University of Southampton, U.K. "Their internal core structure is designed to be dynamic and capable of precise mechanical motion. This mechanical motion, created by applying a tiny bit of pressure, can harness some of the fundamental properties of light to give the fibre new functions and capabilities."
This innovation was achieved by fabricating fibres with two cores—the pathways that carry data in the form of light—that are close enough to each other to be optically coupled, a property of light by which a photon's influence can extend beyond the fibre's core, even though the light itself remains inside. By shifting the position of one of the cores by just a few nanometers, the researchers changed how strongly the light responded to this coupling effect.
If the coupling effect is strong enough, the light immediately jumps from one fibre to the other. "Think of having a train traveling down a two-track tunnel and jumping the tracks and continuing along its way at the same speed," explains Loh. The flexible suspension system of the fibre easily responds to the slightest bit of pressure, bringing the two cores closer together or moving them apart, thereby controlling when and how the signals hop from one core to the other, reproducing, for the first time, the function of an optical switch inside the actual fibre.