Commentary: Glass fiber still beats lasers

By Mark Fabbi, Gartner Analyst

The use of lasers to route data streams through free air will find its place, but it's not likely to become a mainstream optical-networking technology.

Free-space optics technology has been implemented in specialized niche applications for government and scientific projects, as well as in enterprise networks. With the increasing bandwidth limitation of the "last mile" in the service provider infrastructure between the access network and the customer premises, laser technology has been evaluated as a way to deliver increased bandwidth for voice, data and multimedia service offerings.

The technology will likely develop into a niche market that will help to extend the reach of high-speed optical systems starting to come onto the market. In particular, such systems make for an interesting tool for backup facilities.

These lasers will also let service providers deliver high-speed services to selected multi-tenant buildings in urban areas or business parks without laying fiber cables, but rather by connecting laser transceivers between a network node and a rooftop or windowsills.

However, there are some disadvantages of the technology for such service provider applications. The first is a lack of extensive field trial data to provide carrier-grade benchmarks of more than 99.9 percent service reliability.

Second, some environmental materials will intercept the laser beam. Air contains a lot more impurities than glass fiber does, so signals sent by free-space lasers will suffer more degradation.

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Third, the lasers and their system targets would have to remain in strict alignment for data transfer to occur. They would be vulnerable to people moving the equipment on purpose or to accidental vibrations and movement. Accordingly, such systems would need physically secure environments to reduce the likelihood that they would become misaligned.

Fourth, vendors need to address worries about laser safety to accelerate market adoption of laser technology. AirFiber, for one, has done work with automatic power reduction to provide eye safety in case of accidental human blockage between the nodes.

Glass fiber has a big advantage in that respect, so Corning need not worry.

(For related commentary on other wireless data transfer solutions, see TechRepublic.com--free registration required.)

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