The project uses fiber-optic devices that make ultrafast calculations with photons of light instead of the electrons used by electricity-based computers circuits. (Photo by Frank Wojciechowski)
Princeton University – Paul Prucnal, a Princeton professor of electrical engineering, is leading a collaboration between researchers at the University and Lockheed Martin, the aerospace and defense technology corporation, to develop a “photonic neuron,” a device that uses fiber-optic circuits that transmit information a billion times faster than a human neuron.
If the project is successful, the new technology could allow for computer circuits that are capable of making nearly instantaneous calculations in life-or-death situations, such as locating a terrorist from a radio signal or deciding whether to eject a fighter pilot from a jet. It might also allow speedy processing of huge amounts of data, such as the video signals that currently guide the movements of robotic cars or scans of genetic data for clues to fighting diseases.
The project, which started in 2008, seeks to overcome the inherent speed constraints of electrical circuits, which are ultimately limited by the time it takes electricity to flow through wires. Instead of electrical wires, the team is using clear fiber-optic cables, through which information travels at nearly the speed of light. The “photonic” half of the project’s name derives from photons, which are the fundamental unit of light, just as electrons are the fundamental unit of electricity. In conventional fiber-optic communications, photons speed information along great distances but are converted back to electrons once they reach a destination and the information needs to be processed. In Prucnal’s lab, the processing occurs while the information is still encoded in light.
In addition to harnessing the ultimate speediness of light, the researchers are borrowing computational concepts used by the neural circuits that help humans and other organisms make ultrafast decisions.
Each neuron, whether in the brain or peripheral circuits of the nervous system, is connected to other neurons, which communicate through electrochemical pulses known as action potentials, or, colloquially, as “spikes.” Based on the pattern of incoming spikes, a neuron decides whether to send out its own signal to convey information to the rest of the network. This function is the basis for neural computing.
“We are transposing learning, inhibition and other behaviors typical of neural processing onto fiber-optic circuits,” Rosenbluth said. “But I don’t think of it as trying to reproduce something in the brain. It’s a hybrid between the analog computing done in the brain and the purely digital systems used by most computers.”