Prospects for the optical telecommunications industry, which has been stuck in a rut since the burst of the so-called telecom bubble in 2001, are looking up, said Dr. Vincent Chan, a pioneering researcher in the field, who hails from the Massachusetts Institute of Technology (MIT). Chan spoke at a lecture on Tuesday.
Optical fibres are hollow glass cylinders. Photons of light are trapped within, bouncing off their insides like marbles travelling down a tube. They were first used as gastroscopes in the 50s and 60s, to peer inside intestines. In 1980, Chan’s lab at MIT began looking at ways to use these in optical communication links between satellites. By 1986, his lab was testing optical fibres in earth-bound communications networks, an application in which they are now ubiquitous.
Information travels through optical fibres in the form of laser pulses. These fibres carry many times more information than copper wires, at a fraction of their thickness. At first, single laser beams were used to carry information. But later add-ons, such as wavelength division multiplexing (WDM), allowed for multiple laser beams, of different colours, to pipe information through the same fibre.
Later still, optical amplifiers extended the range and speed of optical networks. Since the strength of laser beams slowly fades over distance, laser signals had to be converted back to electronic pulses every so often, the strength of the signal increased, and then converted back to laser pulses. Optical amplifiers obviated this need, by boosting the strength of the signal without converting it to an electronic form. The latest optical networks, especially the long-haul cables that criss-cross the ocean floors, all use this technology.
The dot-com boom at the end of the 90s fueled a frenzy in infrastructure investment among telecommunications companies. The result was a global glut. As expectations of skyrocketing bandwidth use-from technologies such as video on demand, which would allow users to rent movies online, by transferring them directly onto their computers-never materialized, the so-called telecom bubble burst.
Companies such as Global Crossing and Nortel, which had invested tens of billions in optical networks, saw their stock price melt down overnight. “As far as I’m concerned, the world went in suspended animation,” for the last four years, said Chan.
Slowly, some of this excess capacity has been soaked up, given the rise in internet traffic and gaming, especially in Asia. And firms are starting to replenish their inventories.
“They’re beginning to order new equipment,” said Chan, “especially in third-world countries.” China and India, he added, are especially keen on installing the latest optical networks. “It’s starting to build up again, just the last half of this year.”
Researchers now hope that government funding, which all but dried up in the wake of the dot-com bust, will start flowing again. “The U.S. government, at my urging, is now beginning to rearrange optical network funding-it will appear in a year or so,” said Chan.
At U of T, things are looking up as well, according to Dr. Stewart Aitchison in the department of electrical and computer engineering. This summer, his department set up the emerging communications technology institute (ECTI). Several labs were folded into the new outfit, which looks beyond just fibre optic communications.
“It’s not just fibre, that’s the big driver now, things are going towards mobile,” said Aitchison. Cell phones and PDAs are increasingly internet-enabled, through the wireless protocol known as Wi-Fi, and its soon-to-be kin, dubbed Wi-Max, which promises metropolitan-wide wireless coverage. The trick, though, is getting all these systems to speak the same language.
“The areas of research are probably going to be in those new interfaces,” Aitchison said. “You’re interfacing a mobile wireless communications network with an in-ground optical communication system.”
This may not signal a return to 90s bonanza, to be sure, but at least there’s light at the end of the fibre.
