Slowing down light could boost networking

 

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By Stewart Mitchell

Posted on 6 Sep 2010 at 14:34

Breakthroughs in networking normally involve a major speed boost, but researchers have claimed a significant achievement by slowing down the speed of light.

Californian scientists researching photonic chips for use in optical networks claim they have slowed the speed of light by a factor of 1,200 - which makes signals in light far easier to manage.

The scientists from the Baskin School of Engineering at the University of California have developed a tiny optical device built into a silicon chip that has achieved the slowest light propagation on a chip.

Whereas optical fibres routinely transmit data at light speed, network routing and data processing operations still need to convert light signals to electronic signals. All-optical data processing will require compact, reliable devices that can slow, store, and process light pulses.

"The simplest example of how slow light can be used is to provide a data buffer or tunable signal delay in an optical network, but we are looking beyond that with our integrated photonic chip," said Holger Schmidt, professor of electrical engineering.

"Slow light and other quantum coherence effects have been known for quite a while, but in order to use them in practical applications we have to be able to implement them on a platform that can be mass produced and will work at room temperature or higher, and that's what our chips accomplish," Schmidt said.

According to Schmidt, a control laser modifies the optical properties of the gas the data signal is passing through, acting like a pair of photochromic sunglasses.

"By changing the power of a control laser, we can change the speed of light - just by turning the power-control knob," Schmidt said.

The scientists say the quantum effects of the chip not only slow light but also boast other interactions between light and matter that raise the possibility of new optical devices for quantum computing.

"This has implications for looking at nonlinear optical effects beyond slow light," Schmidt said. "We can potentially use this to create all-optical switches, single-photon detectors, quantum memory devices, and other exciting possibilities."