On the Inside
Intel researchers still have to find ways to manufacture silicon lasers alongside electronic components on chips. Electronic circuits are built through the painstaking process of laying down and etching dozens of layers of materials. Some of these steps require temperatures well over 1,000 °C or exposure to caustic chemicals. So Intel’s engineers will need to ensure that the steps required to build up the optical devices don’t degrade the electronic circuitry, and vice versa.
As an initial demonstration of the usefulness of silicon photonics, Paniccia plans later this year to integrate several modulators and other optical components onto a piece of silicon; this setup should enable data transfer speeds of 100 gigabits per second. Such a prototype, hopes Paniccia, will illustrate the potential of silicon photonics to carry data into and out of chips far more efficiently than anything currently on the market.
Walking through one of his newly renovated labs this spring, Paniccia showed off a mock-up of an optical Ethernet cable that would use silicon photonics. While Paniccia normally maintains the modest, careful demeanor of a scientist, it’s clear he relishes using the prop to sell his vision of silicon’s new role. On the end of the spaghetti-strand-thin cable sits a connector that resembles the end of a phone cord, with metal pads sitting under tiny slits in a silicon encasement. In a functional version of the cable, electrical signals would travel from a computer chip through those metal pads to a silicon photonic chip inside the tiny connector, where they would be converted into a stream of light pulses.
While on the outside the cable resembles familiar technology, adding cheap silicon photonics to it would bring unprecedented speed and power to computers. And it would allow Intel to add its famous “Intel inside” branding logo to yet another transforming technology. Realizing that vision won’t be easy. Still, Paniccia is convinced it will happen. “There is no question anymore whether we can do this. It’s when and how. That’s been the change in the last year.” And when the last technical barrier falls, he says, “silicon photonics will be everywhere.”
Robert Service is a Portland, OR-based writer who covers chemistry and materials science for Science.