The market for tunable lasers is expected to grow from US$100 million last year to about $1.5 billion in the next couple of years, according to the research firm ElectroniCast.
"Everyone is saying that tunable is going to be a winner," says Stephen Montgomery, market research consultant for optical communications at ElectroniCast. "There's going to be a huge demand for this stuff over time as copper is replaced by fibre."
Nortel Networks and Lucent Technologies are market leaders, each offering lasers that can tune to 20 different wavelengths.
But start-up Agility Communications claims the lead in breadth of tunability, with a laser in trials that can switch between 100 wavelengths. And Altitun, a Swedish start-up acquired in May by ADC Telecommunications, claims to be the first to market with a tunable laser that can switch wavelengths in nanoseconds, so fast that it can shuffle packet by packet, simplifying the switches on optical networks.
Tunable lasers are key to a faster, fatter Internet. They let networks operate at maximum capacity, switch bottlenecked traffic to uncrowded wavelengths, and potentially can make many costly optical switches unnecessary.
A fibre-optic strand is just skinny glass until it is "lit" when a laser is turned on and, teamed with a modulator, starts blinking signals down the thread of fiber.
A fibre strand is thinner than a human hair. Anything that thin seemingly would be doing well enough to carry just one lane of voice, video and data traffic.
But as demand for bandwidth mushroomed, physicists came up with a lower-cost alternative to digging trenches and laying more conduits in the ground. They developed Dense Wavelength Division Multiplexers (DWDM), which use mirrors or bubbles to divide fibre into several differently colored wavelengths of light.
Each colour can carry its own traffic because each has a very precise and never-varying wavelength - and thus never, or very rarely, bumps into another colour's traffic. Carriers are beginning to deploy DWDM gear that can divide light into as many as 64 wavelengths. In laboratories, scientists have divided light into more than 1,000 wavelengths.
Each wavelength that carries traffic needs a laser to blink on and off billions of times per second and bring to life the ones and zeroes that make up the bits and bytes, the e-mails, songs, movies and charts traveling across a network.
Most lasers on fibre-optic networks today are fixed - that is, once they're assigned to a colour, they stay with it forever. They can't help ease the overflow of traffic if, say, the new Victoria's Secret online fashion show is planned for the same day as the corporation's big videoconference, and they're sharing the same overcrowded path through several switching stations.
Tunable lasers, however, switch traffic to wavelengths that aren't overloaded, easing the bumper-to-bumper conditions.
The goal is a laser that can be tuned across all channels of a DWDM system, but which also can switch channels in a flash and has the oomph to carry the signal a long distance over the network's core. So far, most tunable lasers can only perform one or two of these functions.
