Making light work of broadband

Optical technology that delivers broadband internet access via airborne light beams is to enter commercial use following final tests by its Cambridge developer.

Quantumbeam has, since 1997, been researching Free Space Optics (FSO) as analternative to fibre-optic cables for providing high bandwidth data to homes and offices.

The laser-based system uses light as its communication medium, modulating it into pulses which can be decoded by a receiver.

Quantumbeam will deliver its first live units to customers within the next few months for full-scale trials, and is also exploring industrial applications for its technology.

According to its proponents, FSO is a solution to the ‘last mile’ problem that is widely blamed for delaying the roll-out of broadband in the UK’s urban areas.

The phrase refers to the expensive and disruptive cabling needed to connect local broadband data nodes to thousands of individual premises.

Quantumbeam claimed radio-based transmission of data, the only current alternative, provides lower bandwidth and has the added disadvantage of a heavily-regulated spectrum, while FSO networks are unlicensed.

Building on specialist research first carried out for military applications, Quantumbeam developed the optoelectronic device that now forms the hub of its system.

The hub, which sits in a unit the size of a small hi-fi speaker, allows data to be delivered to multiple users within its line of sight at a rate of 1Gb/s. No bandwidth is lost when a new user joins the system.

According to the UK company, it is unique in attempting to use FSO as the basis of a ‘point-to-multipoint’ data delivery system – one that can serve many users from a single unit.

The handful of other FSO specialists around the world are building point-to-point systems that can send extremely high bandwidth over long ranges.

Andrew Parkes, Quantumbeam’s chief executive, said internal hardware tests designed to qualify the engineering status of the system were almost complete.’We have developed a mass-access system that is easy to install and relatively inexpensive,’ said Parkes.

He added that it would be priced competitively with other access technologies for the home mass-market.

One of the challenges facing Quantumbeam, or any other FSO-based system, is the effect of the weather on its operation. Fog, rain and snow have the potential to disrupt data transfer, and Quantumbeam has been adjusting the system to optimise its performance in adverse conditions.

‘It has proved very robust,’ said Parkes, who admitted that earlier incarnations of FSO systems suffered a significant signal loss during bad weather.

Although it expects the core use of its technology will be data transmission in metropolitan areas, Quantumbeam is also exploring alternative applications with non-communications-based firms.

It is working with an aerospace company to use FSO to transmit data from the onboard diagnostic systems of aircraft as they come into land.

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