Marine fouling of optical fibre micro-cables

The benefits of optical fibre as a data transfer medium are well established and exploited within numerous current applications, where high data rates and minimal cable diameters are required. Data rate requirements in excess of 1 Gbaud, to support the transmission of advanced sensor data, are achievable through single mode optical fibre cables, which may be as small as 0.25 mm outer diameter. This permits significant lengths of cable, occupying a relatively small volume, to be carried and deployed by UUVs, thereby providing a continuous, high bandwidth link, over considerable distance. Such benefits are reliant upon maintaining the integrity of the relatively fragile optical fibre cable in the harsh marine environment. The impact of biological activity within the marine environment is considered an area of risk to the survivability of small diameter optical fibre cables for which very little data exists. DERA are addressing the survivability of deployed optical fibre cables and, in conjunction with the University of Wales Bangor, researching the characteristics of marine fouling colonies and subsequent biological interference with respect to immersed cables. Initial research has been carried out to identify potential risk areas and likely fouling behaviour, which has been validated by in-situ experimentation. This paper highlights the key issues addressed by the current research and presents some results and conclusions from the initial phase of experimentation. The way ahead for the work is indicated, together with its relevance to future marine systems.