Mitel technology bandwidth-boosting

A new technology from Ottawa’s Mitel Corp. could be a breakthrough for companies hoping to increase the bandwidth on their fibre optic lines, and could prove to be a boon to the company within the next two years, according to a director at Canada’s National Research Council (NRC).

The new device, which Mitel is calling LightRider, may improve the price/performance ratio of multiplexing, said Sylvain Charbonneau, the director of components technology at the NRC. Multiplexing is the process of sending more than one wavelength signal across a single fibre optic line.

Currently, many companies employ technology that can carry 16 or 40 channels on one fibre line, but the costs of implementing such technology have limited its use to the Internet backbone. Carriers are eager to find a cheap way to use similar technology, called Dense Wave Division Multiplexing (DWDM), on fibre lines in metropolitan areas.

Charbonneau said Mitel may have achieved that possibility by using old technology in a new way.

“The Mitel design uses a technology which has been around for quite some years, but has never been applied to wave guide (optical fibre) geometries. It involves Echelle grating,” he explained.

Mitel uses the Echelle grating to de-multiplex, or “demux” the signals on a fibre when they reach a cross-connection point, or switch. Charbonneau said that, unlike Arrayed Waveguide Grating, which is currently used to demux fibre lines, an Echelle Grating scales better as demand grows. In short, he said Mitel’s chips can be built smaller, and therefore more easily, and they are less susceptible to temperature fluctuations.

Mitel is also building its LightRider chips on silicon, a material that is at the base of the microelectronics industry but is relatively new to optoelectronics.

“The nice thing about silicon is it is a very well-known material,” Charbonneau said. “In principle, it should reduce the cost of fabrication, and therefore it’s a good thing for the industry.”

Mitel said it plans to provide its lead customers with LightRider samples for evaluation by early next year. The company’s first prototype will mutiplex 40 channels on a single fibre, but it said an 80-channel device is in development.

“At first, (they) will be using the mux-demux applications in the long haul,” Charbonneau said.

“But…I believe it will only be a year, two at the max, before you have the optical network going into the metropolitan (area). And once you have every city in the world connected on optical fibres, you will need a hell of a lot of these mux-demuxes,” he said.