Free-space optics no longer simply a niche solution

May 1, 2001


For three days at the Optical Fiber Communications (OFC 2001) conference in Anaheim, CA, a steady stream of people crowded around the booths sponsored by free-space optical (FSO) equipment manufacturers. That such companies should be popular at OFC is not entirely surprising-according to a recent study from Washington, DC-based Strategis Group, global FSO equipment revenues will jump from less than $100 million in 2000 to approximately $2 billion by 2005, a 1,900% increase. Market researcher Allied Business Intelligence (Oyster Bay, NY) puts global FSO transceiver revenue at more than $4 billion by 2005. A key factor driving the market's growth is its evolution to higher speeds and carrier-class reliability.

"A major shift is underway in the free-space optical market," asserts Andy Fuertes, vice president of communications technologies at Allied Business Intelligence. "While these technologies were used for years in niche applications, they are ready for the delivery of broadband capabilities in mainstream carrier networks."

FSO networks carry high-speed data through the air on beams of light transmitted by highly focused lasers, located on rooftops or in building windows and linked by line of sight. Once regarded as a backup solution for traditional fiber networks, an interim solution for emergency situations or special events, or simply a niche application for connectivity where fiber deployment isn't feasible, FSO technology is becoming increasingly attractive to carriers. According to Allied Business Intelligence, carrier/ access applications will exceed all other FSO segments by 2005, when it will account for more than 70% of the market.

Faced with healthy competition from emerging carriers that can offer Internet Protocol services with higher bandwidth, incumbent carriers have to "fight back," says Stephen Patrick, technical director at Hampton Hills, UK-based FSO vendor CableFree Solutions Ltd. One way they are fighting back is through the deployment of FSO equipment.

"There was a recent figure out of the States that a DSL which costs the end customer $40 per month to rent, in fact, costs $80 per month to maintain by a competitive carrier," he says. "The bandwidth itself, even for a DSL connection, is not a way to make money. The money is in the services, and that's the argument for the future: If you can offer highly differentiated services, you are saving the customer a huge amount of money, because they don't need to hire an IT manager. For the service provider, that's a huge value-add."

For all its potential advantages, FSO technology has historically had its share of obstacles, which must be overcome before widespread carrier adoption is possible. Issues such as the attenuation effects caused by inclement weather, distance limitations, and the need for an uninterrupted line of sight between FSO transceivers have raised reliability questions in the past. There is no shortage of players in the market, however, with each touting its own proprietary (and therefore closely guarded) solution to the reliability problem, leaving carriers with a myriad of options.

LightPointe Communications, which officially unveiled its carrier-class "Flight" product line at OFC, overcomes the reliability issue using a backup hybrid optical/microwave link. Its solution will fit within any carrier network protocol or topology, claims the company, including mesh, point-to-point, ring, and point-to-multipoint. According to the company, the devices are targeted at the metro environment, but carriers have also used them in the metro core, as a last-mile solution, a supplement to radio-frequency (RF) wireless LMDS, and a means to complete SONET/SDH rings.

Optical Access Inc. (Denver) has also recently introduced its carrier-class Optical Access Mesh, which features a built-in RF wireless backup system to mitigate potential downtime caused by weather or building sway. It supports Fast Ethernet and Gigabit Ethernet speeds and includes switching and routing technology that enables bandwidth distribution and provisioning for IP networks, claims the company. Among its current customers are service providers Tellaire Corp. (Dallas) and Broadband Highway (Los Angeles).

Optical Access is a technology investment partner with MRV Communications Inc. (Chatsworth, CA). A new FSO player with a similar connection to MRV is Optical Crossing (Glen dale, CA), which unveiled its Opti Bridge 2500 single-channel FSO transceiver at OFC. The transceiver provides 2.5-Gbit/sec links over distances as long as 2 km. Its proprietary auto-alignment subsystem corrects for both slow building sway and weather conditions. The company claims the system can tolerate atmospheric attenuation of 20 dB over 1 km without a reduction in data rate.

AirFiber's ATM-based OptiMesh product targets facilities-based carriers looking to extend the reach of their existing fiber networks. It may be used in redundant mesh or multiple point-to-point configurations and features shorter links for improved availability. Eight service providers are currently in trials with the OptiMesh.

CableFree Solutions Ltd. has deployed and is currently deploying FSO systems to carriers in the Middle East, the Far East, Africa, Western and Eastern Europe, and the United States. Its products are designed with a "fade margin" that takes into account the worst-case scenario for a given system's location. While the company is reluctant to divulge the exact nature of the fade margin, representatives assert that the technology is reliable enough to cut through fog in London and sandstorms in the Middle East. CableFree's solution is upgradable from 2 to 622 Mbits/sec through 1.5 Gbits/sec.

A relative newcomer to the scene, British Columbia-based fSONA recently unveiled its carrier-grade SONAbeam product, which transmits at speeds ranging from 155 Mbits/sec to 1.25 Gbits/sec and may be configured in numerous topologies, including point-to-point, inter-LAN, and as an extension to existing SONET/SDH rings; fSONA employs a radio-based wireless backup to ward against downtime.

TeraBeam Corp. (San Diego) has chosen an entirely different business plan, opting to act as service provider for its own line of FSO equipment. Targeting enterprise users, TeraBeam recently announced the first commercial customers using its IP network: the Four Seasons Olympic Hotel; Avenue A, digital media advertising agency; Simpson Investment Co.; and a law firm, Preston Gates and Ellis, LLP-all based in Seattle, where fog is a notorious problem. TeraBeam's solution employs a built-in tracking device and an off-the-shelf router to route around possible equipment failures. TeraBeam will soon begin work on another FSO network in Denver, with similar networks to follow in four undisclosed cities before the end of the year.