一种双模压缩微波制备的相位锁定方案  

A phase locking scheme of two-mode squeezed microwave preparation

作　　者：魏天丽 吴德伟[1] 杨春燕[1] 罗均文 苗强[1] 李响[1] Wei Tian-Li;Wu De-Wei;Yang Chun-Yan;Luo Jun-Wen;Miao Qiang;Li Xiang(Information and Navigation College,Air Force Engineering University,Xi’an 710077,China)

机构地区：[1]空军工程大学信息与导航学院

出　　处：《物理学报》2020年第3期132-138,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:61603413,61573372);陕西省自然科学基金(批准号:2017JM6017);空军工程大学校长基金(批准号:ZJK2018019,XZJY2018038)资助的课题~~

摘　　要：相位锁定是双模压缩微波制备的关键问题之一.针对基于超导180°混合环的制备方案相位稳定度不高且信息处理复杂等问题,提出一种相位锁定方案.对约瑟夫森参量放大器的信号输入进行相位调制,输出的单模压缩微波与另一未调制的同频单模压缩微波在超导180°混合环内干涉,实现双模压缩微波的制备与路径分离.将未调制的单模压缩微波与一路双模压缩微波混频,解调出相位调制信号可得到两路单模压缩微波的相对相位及误差,将相位误差反馈于约瑟夫森参量放大器的抽运实现相对相位的锁定,获得稳定的双模压缩输出.本研究对高性能纠缠微波源的设计提供了理论参考.As the core of quantum entanglement,two-mode squeezing is manifested in cross-correlations of incompatible observables between two subsystems,which makes the two-mode squeezed microwave an ideal resource for applications in quantum communication,quantum illumination,and quantum microwave navigation.Currently the preparation scheme of two-mode squeezed microwave,based on the Josephson parametric amplifier(JPA)and a superconducting 180°hybrid ring coupler,proves to be the most efficient and excellent in quantum properties.Nevertheless,the difficult phase locking processing restricts the further improvement of entanglement.There is no effective solution but the dual-path receiver with phase stabilization measures,and the phase error reaches as high as 0.3°,which still does not meet the requirements for phase locking precision and entanglement stability.To overcome the academic obstacle,we propose a phase locking scheme to achieve a stable two-mode squeezed microwave.There are two JPAs used to separately generate single-mode squeezed microwaves,between which the difference lies in the fact that the input of one JPA is phase-modulated but the other is not.A superconducting 180°hybrid ring coupler is used to distribute the two single-mode squeezed microwaves into two output paths,which are two-mode squeezing if the squeezing directions of the two single-mode squeezed microwave are orthogonal.That is to say,the relative phase satisfies the condition θ=π/2.By mixing the unmodulated single-mode squeezed microwave and one output of the superconducting 180°hybrid ring coupler,a relative phase is obtained in subsequent process.Proportional integral derivative(PID)controller is used as the input of phase error,and the output is used to adjust the pump phase of JPA,which is the key to phase locking and stable two-mode squeezing.The present research not only provides an effective strategy to achieve stable two-mode squeezed microwave,but also may attract more attention to the precisive measurement of two-mode squeezed mic

关 键 词：双模压缩微波 相位锁定 

分 类 号：O413[理学—理论物理] TN911.3[理学—物理]