A 5 GHz and 7.5 V multi-amplitude modulator driving circuit for practical high-speed quantum key distribution

Xiang Liu; Ming-Qi Huang; Hao Min; Ge Jin; Xiao Jiang; Cheng-Zhi Peng

doi:10.1063/1.5140695

A 5 GHz and 7.5 V multi-amplitude modulator driving circuit for practical high-speed quantum key distribution

Rev Sci Instrum. 2020 Feb 1;91(2):024705. doi: 10.1063/1.5140695.

Authors

Xiang Liu¹, Ming-Qi Huang¹, Hao Min¹, Ge Jin¹, Xiao Jiang¹, Cheng-Zhi Peng²

Affiliations

¹ Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
² CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.

PMID: 32113405
DOI: 10.1063/1.5140695

Abstract

Quantum key distribution (QKD) offers the ability of information theoretic security key exchange. The secure key rate is an important indicator for the practical QKD systems, which determines what kinds of applications can be supported. One most effective way to enhance the secure key rate is to increase the system repetition frequency. Here, we report an implementation of a high-speed DC-coupled modulator driving circuit with a repetition rate of up to 5 GHz. The circuit outputs a multi-amplitude return-to-zero pattern pulse with a maximum amplitude of 7.5 V. The design adapts to the various electro-optic modulators widely employed in QKD systems. The minimum pulse width is measured as 75 ps, with the relative noise level less than 1.5% for all the output amplitudes under random modulation.