Prof. PAN Jianwei and Prof. ZHANG Jun from University of Science of Technology of China (USTC), collaborating with Prof. CHU Tao's group from Zhejiang University, realized the fastest and miniaturized real-time quantum random number generator (QRNG) with the record-breaking output rate of 18.8 Gbps by combing a state-of-the-art photonic integrated chip with the optimized real-time post processing. The study was published in Applied Physics Letters on June 29.

This work was published as the cover paper

Random number exists in many fields such as information security and cryptology industries. Different from other random number generators, QRNG, as the key part in quantum communication system, embraces the characteristics of unpredictability, irreproducibility, and unbiasedness.

Density of integration and real-time generating rate are the two key indicators for QRNG. It is hard to realize high density of integration via existing methods.

Prof. PAN and Prof. ZHANG perfected the high-speed quantum generation scheme which extracts randomness from vacuum states, and completed the verification of relevant experiments.

Collaborating with the researchers from Zhejiang University, they produced the photonic integrated chips required by this vacuum state scheme. They butterfly packaged a photonic integrated chip, including an InGaAs homodyne detector and a high-bandwidth transimpedance amplifier (TIA), with a bigger size of 15.6 mm×18 mm.

Schematic figure for the QRNG

The random number real-time generating rate as well as high density of integration of QRNG has been improved through an optimized real-time post-processing algorithm in a field programmable gate array (FPGA) and hardware implementation.

The system QRNG finally realized the world-beating rate at 18.8 Gbps after passing the transmitting test.

Paper link:

https://aip.scitation.org/doi/full/10.1063/5.0056027

(Written by WANG Jinhua, edited by JIANG Pengcen, USTC News Center)