Holographic Optimisation of Multi-Mode Fibres
There are literally billions of kilometres of multimode optical fibre installed around the world. All of which is susceptible to modal dispersion, an effect increasingly important as networks move to and beyond 10GbE. Modal dispersion is a consequence of the fact that each mode of a fibre propagates information with a slightly different speed causing sharp pulses to become smeared and distorted over long distances or at high signalling rates.
As mentioned, the installed base of fibre installed in walls, ceiling, under roads etc. around the world is extensive and continual innovation is required to push the limits of this infrastructure to higher bandwidths and avoid any requirement to rip out and reinstall new fibres.
This presentation briefly summarises modal dispersion and modal coupling and how it can be combated by holographic control of the coupling of light into the fibre. Beyond this it outlines the concept behind holographic mode-group division multiplexing where each of the modes of an optical fibre is exploited to propagate independent channels and the benefits of holography become more marked.