Optical Multi-Input Multi-Output systems for short-range free-space data transmission

Radio Frequency Multi-Input Multi-Output (MIMO) systems are becoming ubiquitous, due to the ability of spatial multiplexing to increase capacity where there is limited spectrum available, and the power that can be transmitted is limited by spectral regulation. MIMO techniques have been applied to free-space optical interconnection and data transmission to a limited extent. This paper discusses progress in this area, particularly in the context of indoor optical wireless systems. The nature of the optical channel is compared to RF, together with the physical components available to undertake MIMO transmission. Results from some preliminary experiments and simulations are also shown.