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Don't Blink Or You Might Miss The Next Big (Quantum) Thing

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Integrated circuits make the thousands of necessary computations, and “given the need for miniaturization, the best way to reduce the size of those circuits would make them fully photonic,” Christensen says. That step, however, is some time off. For semiconductor laser structures, Christensen works with Evans. The two have just started a project, also for DARPA, in collaboration with the University of Texas at Dallas, Photodigm, Raytheon and Northrop Grumman. The goal: To develop signal processing with photons, instead of electrons; in other words, computing with light.

To achieve this they must create the photonic equivalent of a semiconductor chip. Most computer chips are made with silicon, which doesn’t emit light very well. A better choice is indium (In) phosphide (P), called a III-V semiconductor, Christensen says. The goal is to emit and control light, one photon at a time. “At the quantum level you are literally controlling individual photons and providing gain (to amplify signals).” Christensen compares the current state of photonic integrated circuits with the world’s first electronic integrated circuit, invented at Texas Instruments 50 years ago this summer by the late Jack Kilby when he linked a handful of transistors on a single silicon chip. Over the next 50 years, semiconductors evolved from a handful of components on that first chip to hundreds of millions of components on a single chip, he says.

“If you look at the state of photonics processing, it’s about 6 to 15 components,” he says. “It’s like we’re starting today where Jack Kilby was 50 years ago, and it will be interesting to see where a few decades takes the field of integrated photonics.”



For more informaton: engr.smu.edu/ee/research.html