Self-organization of light in multicore optical fibres: a route to scalable high-power lasers and all-optical signal processing

Optical fibers are nowadays ubiquitous and exploited in a multitude of applications, from telecommunications to high-power lasers. The last decade has seen the emergence of a new type of optical fiber, the so called multicore (MC) fiber. Unlike traditional fibers, where only a single core is used to carry the light beam, MC fibers are characterized by having a multitude of cores, each one carrying a different light beam. In each core, light can travel in one direction (forward) or in the opposite direction (backward). When forward and backward light beams are simultaneously present, we refer to a counter-propagating configuration. This project aims to study the coupling dynamics between beams of different cores in a counter-propagating configuration, and to demonstrate its application in some important technological areas, ranging from high-power lasers through to telecommunications. Preliminary studies carried out by the team members indicate that when the cores are sufficiently close, then strong coupling induced by the counter-propagating configuration may occur, such that the beams in each core organize themselves in to regular well-defined patterns. For example, the forward beams in each core and exiting the fiber may end up with the same phase irrespective of their initial phase. These results imply natural application in coherent beam combination, which refers to the ability to combine multiple independent light beams so as to obtain a single beam characterized by a high brightness and beam quality at the system output. It is worth noting that here, differently from current state-of-the-art solutions, beam combination is achieved in an all-optical way, that is to say without resorting to the use of complex and power-consuming electronic control systems. Indeed it is the beams themselves in each core that self-organize due to their mutual coupling. In this project we will design, fabricate and test bespoke MC fibers where the proposed all-optical beam combination is exploited to build high-power optical sources and novel optical devices for the next generation Internet. Moreover, a general theoretical framework will be developed that will find application not only in optics but also in other important disciplines, such as hydrodynamics. The wide range of skills required for the development of the project will be covered by a multidisciplinary team at the Optoelectronics Research Centre (ORC) of the University of Southampton. The ORC is a world leading academic institution with some of the most advanced laboratories for fiber manufacture and experiments available on the planet.