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

作　　者：Pingyu Zhu Yingwen Liu Chao Wu Shichuan Xue Xinyao Yu Qilin Zheng Yang Wang Xiaogang Qiang Junjie Wu Ping Xu 朱枰谕;刘英文;吴超;薛诗川;于馨瑶;郑骑林;王洋;强晓刚;吴俊杰;徐平(Institute for Quantum Information&State Key Laboratory of High Performance Computing,College of Computer,National University of Defense Technology,Changsha 410073,China;National Innovation Institute of Defense Technology,AMS,Beijing 100071,China;National Laboratory of Solid State Microstructures and School of Physics,Nanjing University,Nanjing 210093,China)

机构地区：[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

出　　处：《Chinese Physics B》2020年第11期135-139,共5页中国物理B（英文版）

基　　金：Project 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);the Open Funds from the State Key Laboratory of High Performance Computing of China(HPCL,National University of Defense Technology).

摘　　要：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 spectralpurity 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.

关 键 词：spectral-purity micro-ring Mach–Zehnder interferometer 

分 类 号：O433[机械工程—光学工程]