Ontario firm goes acoustic with all-optical switch

Despite boasting must faster speed and more output ports, Burlington, Ont.’s Light Management Group (LMGR) Inc.’s new all-optical switch is hampered by the same limitations as the current generation of electrical-core switches, according to one industry observer.

Specifically, the problem with LMGR’s new switch is that it only has one input fibre or port, said Bill St. Arnaud, senior director of Network Projects for CANARIE, an Ottawa-based Internet development organization.

“That’s where they’re going to run into the challenge

– it’s doing 1024X1024 (ports),” St. Arnaud said. “1×1024 (which LMGR offers), that’s easy. Doing any point to any point, a true cross bar switch, is very, very hard in the optical loop plain.”

Although LMGR says it is in the process of developing

a way to increase the amount of input ports on its optical switch, company president Don Iwacha said it still feels it has a market in the long-haul switching market with its 1×1024 switch.

“If you look at the ring architecture that runs from

the long-haul networks, the rings are basically unidirectional,” Iwacha said. “They may have two adjacent rings running in the same direction or opposite, but the direction of the flow of information is unidirectional, so for the current switch it is perfect.”

Iwacha said LMGR is planning to market the switches, which are sold as a sub-system not as a full switching technology, to major carrier vendors rather than service providers. That way, the vendors can either retrofit their current switches by implanting LMGR’s new optical core or install them on new switches.

Most optical switches in use today convert light pulses to electrical signals for routing purposes and then boost them back to optical signals. Industry experts say there are two problems with this design. The first is that as scientists develop new ways of putting more wavelengths on fibre (commonly called dense wavelength-division multiplexing, or DWDM) the electrical cores might only be able to scale up to support a 512-by-512 electrical core. The second is that there are costs and slowdowns with the optical-electrical-optical conversion.

Light Management Group’s new switch offers switching

speeds a thousand times faster than current electrical-core switches (with routing delays of only five microseconds) and does not have any moveable parts, making it possibly more reliable than mechanical switches.

It incorporates an acousto-optic technology, which essentially means it uses sound to vibrate crystals, which then route the incoming light pulses. The technology is in use today in some movie projectors and lab equipment. Light Management Group, which was formed in a reverse merger with Nevada-based Tritan Corp. in May 1999, has been using the technology in advertising billboards. The new switch marks the company’s first foray into the switching market.

St. Arnaud said there is definitely a market for all-optical switches, but a small company like LMGR faces an uphill battle in selling its product on the long-haul market unless the company’s technology is adopted by a major carrier vendor.

“If you’re a big telephone company, you trust Nortel and Lucent to build the gold-plated, five-nines reliability,” St. Arnaud said. “For a small company, it’s really tough to break into the carrier market.”

LMGR also faces challenges due to the fact that almost every major carrier vendor, including Alcatel, Nortel, Agilent, JDS and Corning, is working on some form of all-optical switch technology. The technologies being developed are varied. Some incorporate arrays of tiny tilting mirrors, while others use the surfaces of tiny bubbles to act like mirrors and route the light pulses.

One of the concerns over all-optical switches is the

extra cost-per-port versus electrical-core switches, said St. Arnaud.

“And that’s the big debate. If you’re just switching

Internet traffic in gigabit Ethernet, the compelling market reasons are pretty limited,” he said. “If you’re a carrier and you have mixed traffic – Internet, voice and video – and you’re at very high data rates, say 40Gb per channel, then optical switches start to make sense.”

The optical lines employing LMGR’s proprietary commutator can carry 10GB of information per

second, according to the company.

Iwacha did not detail the cost of his company’s switch, except to suggest that it would be cheaper to install a brand new switching facility with its all-optical core because there is less hardware and control mechanisms required.

The company is taking orders now and shipping will commence in four to five months, Iwacha said. LMGRR is on the Web at www.LMGRr.net.