Lasers point way to high-speed links

By Simon Aughton

Posted on 11 Jun 2003 at 13:13

A 30 year old technology could be the next big thing in high volume data transfer technologies, with the emergence of commercially viable Free Space Optics.

Free Space Optics (FSO) uses lasers to transfer data at speeds as high as 2.5Gb/sec. Not a networking technology as such, FSO is best used to provide fixed links between business sites or as a backbone between separate local area networks. Its impact could be most keenly felt ion the emerging market for metropolitan area network (MANs), allowing local authorities or businesses to provide high-speed broadband access by means of a series of interlinked local networks, either wired or wireless.

There are, of course, limitations on any laser based connection, largely because the technology relies upon line of sight. In other words the devices that both transmit and receive the data must be able to 'see' each other without any physical obstructions such as buildings in the way. Fiber optic cables - the fixed alternative to FSO - do not have this problem, but do have other limitations. As www.freespaceoptics.org points out, 'once fiber is deployed, it becomes a "sunk" cost and cannot be re-deployed if a customer relocates or switches to a competing service provider, making it extremely difficult to recover the investment in a reasonable timeframe.' And it, 'is subject to outside disturbances from wayward construction backhoes, gnawing rodents and even sharks when deployed under sea.'

FSO has already proved is worth, with LightPointe successfully installing a link between two sites for a Dublin-based business at about one eighth of the cost of a 100Mbps fixed leased line. But the longer term implication is the elimination of bottlenecks between local networks and from LANs to the wider Internet.