Excerpt from Semiconductor Engineering’s Power/Performance Bits

Small quantum random number generator

Researchers from the University of Science and Technology of China and Zhejiang University developed a quantum random number generator (QRNG) that small and low power enough to be portable. It utilizes a photonic IC with optimized real-time postprocessing for extracting randomness from quantum entropy source of vacuum states.

“Recently, the technology of integrated quantum photonics has exhibited significant advantages in terms of size reduction,” said Jun Zhang of the University of Science and Technology of China. “In this work, we further prove that such technology could be used for ultrafast, real-time quantum random number generation.”

The group’s chip uses indium-germanium-arsenide photodiodes and a transimpedance amplifier integrated onto a silicon photonics chip that includes several couplers and attenuators. Combining these components allows the QRNG to detect signals from a quantum entropy source with significantly improved frequency response.

“The surprising point in our work is that the high-frequency response performance of the final photonic integrated chip is better than expected,” Zhang said.

Once randomness signals are detected, they are processed by a field programmable gate array, which extracts truly random numbers from the raw data. The resulting device can generate numbers at 18.8 gigabits per second, which the team said is a new world record. The random numbers can then be sent to any computer via a fiber optic cable. Plus, the chip measures 15.6 by 18.0 millimeters, smaller than most current QNRG modules or instruments.

“Based on our present work, in the future, we will develop a low-cost single chip of QRNG with moderate random bit rate, at the level of megabits per second, for commercial uses,” Zhang said. “Such a single chip could be very useful in diverse electronic systems requiring random numbers or signals and even in mobile phones to improve the security.”