Researchers at Purdue University have helped design a compact switch that enables light to be more reliably confined to small computer chip components for faster information processing.
Photons, or units of light, are faster than electrons and could, therefore, process information faster from smaller chip structures. The switch was designed in collaboration with researchers from ETH Zürich, the University of Washington and Virginia Commonwealth University. It bypasses a tendency for the unwanted absorption of light when using surface plasmons—light coupled to oscillations of free electron clouds—to help confine light to a nanoscale.
“The big idea behind this is going from electronic circuitry to photonic circuitry,” said Vladimir Shalaev, Purdue’s Bob and Anne Burnett Distinguished Professor of Electrical and Computer Engineering. “From electronics to photonics, you need some structures that confine light to be put into very small areas. And plasmonics seem to be the solution.”
Even though plasmonics downsizes light, photons also get lost, or absorbed, rather than transferred to other parts of the computer chip when they interact with plasmons.
To address this problem, researchers developed a switch known as a ring modulator that uses resonance to control whether light couples with plasmons. This ring modulator results in a smaller “footprint” because plasmons enable confinement of light down to nanoscale chip structures, Shalaev said.
The researchers plan to make this modulator fully compatible with CMOS transistors, paving the way to truly hybrid photonic and electronic nanocircuitry for computer chips.
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