中国物理B ›› 2020, Vol. 29 ›› Issue (11): 114201-.doi: 10.1088/1674-1056/abbb28

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Pingyu Zhu(朱枰谕)1, Yingwen Liu(刘英文)1, Chao Wu(吴超)1, Shichuan Xue(薛诗川)1, Xinyao Yu(于馨瑶)1, Qilin Zheng(郑骑林)1, Yang Wang(王洋)1, Xiaogang Qiang(强晓刚)2,1, Junjie Wu(吴俊杰)1, Ping Xu(徐平)1,3,   

  • 收稿日期:2020-09-21 修回日期:2020-09-21 接受日期:2020-09-24 出版日期:2020-11-05 发布日期:2020-11-03

Near 100% spectral-purity photons from reconfigurable micro-rings

Pingyu Zhu(朱枰谕)1, †, Yingwen Liu(刘英文)1, †, Chao Wu(吴超)1, Shichuan Xue(薛诗川)1, Xinyao Yu(于馨瑶)1, Qilin Zheng(郑骑林)1, Yang Wang(王洋)1, Xiaogang Qiang(强晓刚)2,1, Junjie Wu(吴俊杰)1, and Ping Xu(徐平)1,3,, ‡   

  1. 1 Institute for Quantum Information & State Key Laboratory of High Performance Computing, College of Computer, National University of Defense Technology, Changsha 410073, China
    2 National Innovation Institute of Defense Technology, AMS, Beijing 100071, China
    3 National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China
  • Received:2020-09-21 Revised:2020-09-21 Accepted:2020-09-24 Online:2020-11-05 Published:2020-11-03
  • Contact: These authors contributed equally to this work. Corresponding author. E-mail: pingxu520@nju.edu.cn
  • Supported by:
    the National Basic Research Program of China (Grant Nos. 2017YFA0303700 and 2019YFA0308700), the National Natural Science Foundation of China (Grant Nos. 61632021 and 11690031), and the Open Funds from the State Key Laboratory of High Performance Computing of China (HPCL, National University of Defense Technology).

Abstract:

We propose an on-chip reconfigurable micro-ring to engineer the spectral-purity of photons. The micro-ring resonator is designed to be coupled by one or two asymmetric Mach–Zehnder interferometers and the coupling coefficients hence the quality-factors of the pump and the converted photons can be dynamically changed by the interferometer’s internal phase-shifter. We calculate the joint-spectrum function and obtain the spectral-purity of photons and Schmidt number under different phases. We show that it is a dynamical method to adjust the spectral-purity and can optimize the spectral-purity of photons up to near 100%. The condition for high-spectral-purity photons is ensured by the micro-ring itself, so it overcomes the trade-off between spectral purity and brightness in the traditional post-filtering method. This scheme is robust to fabrication variations and can be successfully applied in different fabrication labs and different materials. Such high-spectral-purity photons will be beneficial for quantum information processing like Boson sampling and other quantum algorithms.

Key words: spectral-purity, micro-ring, Mach-Zehnder interferometer