A team of engineers from the University of California, Berkeley has demonstrated the first processor that uses light for ultrafast communications. After successfully joining electrons and photons within a single-chip microprocessor, this landmark development opens the door to super-fast, low-power data crunching.

In the experiment cited by Nature, the team loaded two processor cores with more than 850 photonic components and 70 million transistors onto a 3-by-6-millimetre chip. They constructed the microprocessor in an assembly plant that produces high-performance computer chips, indicating that this design can be easily and quickly scaled up for mass production.

“This is a milestone. It’s the first processor that can use light to communicate with the external world,” lead developer Vladimir Stojanović, an associate professor of electrical engineering and computer sciences at the University of California, Berkeley, said in a press release. “No other processor has the photonic I/O in the chip.”

The engineers believe that this new chip signifies the next step in the evolution of fibre optic communication technology by incorporating into a microprocessor the photonic interconnects or inputs and outputs (I/O) required to communicate to other chips. Berkeley professor Krste Asanović remarked that this is the first time the chip has been employed in a system at such scale and used for running a programme.

Advances in optical communication technology have improved data transfers between computers; however, taking photonics into the computer chips themselves had been difficult. The electronic-photonic processor chip communicates directly using light. Researchers said the reason for this is no one figured out how to integrate photonic devices into the same fabrication processes used to produce computer chips without changing the process itself, until now.

The team proved that the chip had a bandwidth density of 300 gigabits per second per square millimetre, which is 10 to 50 times greater than other electrical-only microprocessors available on the market, verifying the chip’s functionality. Additionally, the chip is energy-efficient, consuming only 1.3 watts of power to transmit one terabit of data per second.

“The advantage with optical is that with the same amount of power, you can go a few centimetres, a few metres or a few kilometres,” study co-lead author Chen Sun claimed. “For high-speed electrical links, 1 metre is about the limit before you need repeaters to regenerate the electrical signal, and that quickly increases the amount of power needed. For an electrical signal to travel 1 kilometre, you’d need thousands of picojoules for each bit.”

The engineers believe that this technology comes at the right time as the world pledges to find a solution for global warming. Moreover, the team insists that the research may be used in various applications including neuroimaging, environmental biosensors and LIDAR, the light radar technology needed to guide self-driving vehicles and eyes of a robot.

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