There’s a reason that the Internet backbone is made of fiber-optic cables: photons transport bits of information faster than electrons. But while photons and fiber are the most efficient way of sending data across continents, it’s still cheaper and easier to use electrons in copper wiring for most data transfer over shorter distances.
Now Intel plans to sell inexpensive cables with fiber-optic-caliber speed to connect, for instance, a laptop and an external hard drive, or a phone and a desktop computer. At the Intel Developer Forum (IDF) in San Francisco Wednesday, the company announced a new type of optical cable that it hopes will be fast, cheap, and thin enough to make it an attractive replacement for multiple copper wires.
By 2010, says Dadi Perlmutter, vice president of Intel’s mobility group, the company hopes to ship an optical cable called Light Peak that will be able to zip 10 gigabits of data per second from one gadget to another, a rate equivalent of transferring a Blu-ray movie from a computer to a mobile video player in 30 seconds. A single Light Peak cable will also be capable of transporting different types of data simultaneously, meaning it will be possible to back up a hard drive, transfer high-definition video, and connect to a network with just one line.
At both ends of a Light Peak cable are chips that contain devices that produce light, encode data in it, and send it on its way. The chips can also amplify incoming signals and convert the light to an electrical signal that can be interpreted by gadgets. The first generation of Light Peak will use chips made with standard optical materials such as gallium arsenide. However, to truly make optical cables cheap enough to replace copper, future versions of Light Peak, which will handle 40-gigabits-per-second and 100-gigabits-per-second transfer rates, will most likely need to rely on silicon-based optical chips, a product of the maturing field of silicon photonics. Silicon photonics researchers hope to transform computing by making high-bandwidth connectors cheaper than ever before, not just in cables, but also eventually within electronic motherboards and microprocessors.
“This will be a long-term transition,” says Perlmutter, referring to the fact that it takes years to develop and adopt standards for new connecting technologies. On stage during his IDF keynote, he held up in one hand a bundle of cables he currently lugs around with his laptop, and in the other, a thin, white Light Peak prototype cable. “I have a very light notebook,” he said, “but carry a huge amount of cables with me.”
Intel has already made a name for itself in silicon photonics. In 2005, the company announced a silicon laser, an engineering feat that many thought was impossible due to the physical properties of silicon. And within a couple of years, the company’s engineers demonstrated other silicon-based optical devices, such as high-performing modulators for encoding data onto light, and high-performing detectors for capturing the light-encoded data. Other researchers and companies, including those at University of California at Santa Barbara, University of Southern California, and MIT joined the fledgling field of silicon photonics. In 2007, optical chipmaker Luxtera announced an optical cable called Blazar that contained some silicon-based chips and was designed to connect servers in data centers.
The first generation of Light Peak cables will use the same sort of $75 optical chips found in telecommunications devices. But Intel has employed some tricks to drive down cost by more than a factor of 10, says Victor Krutul, director of Intel’s optical I/O team. For one, the chips don’t need to transmit data over the distances of telecom devices. For another, they don’t need to last as long or withstand harsh conditions. Because telecom chips in consumer cables won’t need to last for decades or withstand heat and humidity, manufacturing standards can be relaxed and allow the chips to be made more inexpensively.
While cables may not seem a cutting-edge technology, says Alan Willner, professor of electrical engineering at the University of Southern California, it is the ideal early application for silicon photonics because the market is potentially huge. “Silicon-based cables provide high-bandwidth connections, and frankly, nowadays everything is high-bandwidth.” Willner adds that the devices inside the chips, such as lasers and detectors, may not be the highest-performing, but they don’t have to be. “What they do have to be is robust and cheap and manufacturable,” he says. “From a user’s point of view, all they see is a lighter, cheaper, and faster cable than what used to be. That’s a great thing.”
“We’re launching an optical technology for a mainstream platform,” says Mario Paniccia, director of Intel’s photonics technology lab. “We’re going to start at 10 gigabits per second and scale to 100 gigabits per second.” Paniccia was reluctant to forecast a timeframe for silicon photonics to be used in Light Peak, but in order to achieve the higher bandwidths, he says, silicon photonics will need to come into play.
Intel says it will be able to make Light Peak cables up to 100 meters long. And because new connective technologies, be they wireless or wired, require standards and industry collaboration, Intel is working to form partnerships with various companies. At the developer forum, Perlmutter announced that Sony is supportive of the technology, with more announcements planned.