First chip that uses light for data transfer developed

A microprocessor chip that uses light, rather than electricity, to transfer data at rapid speeds while consuming minute amounts of energy has been developed by researchers, including those of Indian-origin.
The new technology could pave the way for faster, more powerful computing systems and network infrastructure.
"Light based integrated circuits could lead to radical changes in computing and network chip architecture in applications ranging from smartphones to supercomputers to large data centres, something computer architects have already begun work on in anticipation of the arrival of this technology," said Milos Popovic, assistant professor at the University of Colorado Boulder in US.

Traditional microprocessor chips - found in everything from laptops to supercomputers - use electrical circuits to communicate with one another and transfer information.
In recent years, however, the sheer amount of electricity needed to power the ever-increasing speed and volume of these data transfers has proven to be a limiting factor.
To overcome this obstacle, the researchers including Rajesh Kumar also from CU-Boulder turned to photonics, or light-based, technology.

Sending information using light rather than electricity reduces a microchip's energy burden because light can be sent across longer distances using the same amount of power.
"One advantage of light based communication is that multiple parallel data streams encoded on different colours of light can be sent over one and the same medium - in this case, an optical wire waveguide on a chip, or an off-chip optical fibre of the same kind that as those that form the Internet backbone," said Popovic, whose team developed the technology in collaboration with a team led by Rajeev Ram, a professor at Massachusetts Institute of Technology (MIT).

"Another advantage is that the infrared light that we use - and that also TV remotes use - has a physical wavelength shorter than 1 micron, about one hundredth of the thickness of a human hair," said Popovic.
"This enables very dense packing of light communication ports on a chip, enabling huge total bandwidth," he said.
The new chip has a bandwidth density of 300 gigabits per second per square millimetre, about 10 to 50 times greater than current packaged electrical-only microprocessors.
Measuring just 3 millimetres by 6 millimetres, the chip bridges the gap between current high-speed electronics manufacturing and the needs of next-generation computing for chips with large-scale integrated light circuits.

It retains state-of-the-art traditional electronic circuitry while incorporating 850 optical input/output (I/O) components in order to create the first integrated, single-chip design of its kind.
"This is a milestone. It's the first processor that can use light to communicate with the external world," said Vladimir Stojanovic, associate professor at the University of California, Berkeley.
The study was published in the journal Nature.