›› 2014, Vol. 23 ›› Issue (8): 80304-080304.doi: 10.1088/1674-1056/23/8/080304

• GENERAL • 上一篇    下一篇

An autobias control system for the electro–optic modulator used in a quantum key distribution system

陈文芬, 魏正军, 郭莉, 侯丽燕, 王赓, 王金东, 张智明, 郭建平, 刘颂豪   

  1. Laboratory of Nanophotonic Functional Materials and Devices (SIPSE) and Laboratory of QuantumEngineering and Quantum Materials, South China Normal University, Guangzhou 510006, China
  • 收稿日期:2013-09-14 修回日期:2014-02-25 出版日期:2014-08-15 发布日期:2014-08-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 61108039), the Major Research Plan of the National Natural Science Foundation of China (Grant No. 91121023), and the Scientific Research Foundation of Graduate School of South China Normal University (Grant No. 2012kyjj224).

An autobias control system for the electro–optic modulator used in a quantum key distribution system

Chen Wen-Fen (陈文芬), Wei Zheng-Jun (魏正军), Guo Li (郭莉), Hou Li-Yan (侯丽燕), Wang Geng (王赓), Wang Jin-Dong (王金东), Zhang Zhi-Ming (张智明), Guo Jian-Ping (郭建平), Liu Song-Hao (刘颂豪)   

  1. Laboratory of Nanophotonic Functional Materials and Devices (SIPSE) and Laboratory of QuantumEngineering and Quantum Materials, South China Normal University, Guangzhou 510006, China
  • Received:2013-09-14 Revised:2014-02-25 Online:2014-08-15 Published:2014-08-15
  • Contact: Wei Zheng-Jun E-mail:weizjweizj@126.com
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 61108039), the Major Research Plan of the National Natural Science Foundation of China (Grant No. 91121023), and the Scientific Research Foundation of Graduate School of South China Normal University (Grant No. 2012kyjj224).

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摘要： In a quantum key distribution system, it is crucial to keep the extinction ratio of the coherent pulses stable. This means that the direct current bias point of the electro-optic modulator (EOM) used for generating coherent pulses must be locked. In this paper, an autobias control system based on a lock-in-amplifier for the EOM is introduced. Its drift information extracting theory and control method are analyzed comprehensively. The long term drift of the extinction ratio of the coherent pulses is measured by a single photon detector, which indicates that the autobias control system is effective for stabilizing the bias point of the EOM.

关键词: quantum key distribution, electro-optic modulator, autobias control, lock-in-amplifier

Abstract: In a quantum key distribution system, it is crucial to keep the extinction ratio of the coherent pulses stable. This means that the direct current bias point of the electro-optic modulator (EOM) used for generating coherent pulses must be locked. In this paper, an autobias control system based on a lock-in-amplifier for the EOM is introduced. Its drift information extracting theory and control method are analyzed comprehensively. The long term drift of the extinction ratio of the coherent pulses is measured by a single photon detector, which indicates that the autobias control system is effective for stabilizing the bias point of the EOM.

Key words: quantum key distribution, electro-optic modulator, autobias control, lock-in-amplifier

中图分类号:  (Quantum cryptography and communication security)

  • 03.67.Dd
42.79.Hp (Optical processors, correlators, and modulators) 07.05.Dz (Control systems)