Sagnac光纤环制备并分离简并关联光子对的实验研究  

Experimental research on generating and splitting degenerate correlated photon pairs in Sagnac fiber loop

作　　者：杨磊[1] 刘楠楠[1] 李小英[1] 

机构地区：[1]天津大学精密仪器与光电子工程学院,光电信息技术教育部重点实验室,天津300072

出　　处：《物理学报》2016年第19期72-78,共7页Acta Physica Sinica

基　　金：国家自然科学基金青年科学基金(批准号:11504262);国家重大科研仪器研制项目(批准号:11527808);国家重点基础研究发展计划(批准号:2014CB340103);高等学校博士学科点专项科研基金(批准号:20120032110055);天津市应用基础与前沿技术研究计划(青年项目)(批准号:14JCQNJC02300);光电信息技术教育部重点实验室(天津大学)开放基金(批准号:2015KFKT014)资助的课题~~

摘　　要：光纤中自发四波混频过程产生的频率简并关联光子对是实现量子信息处理和高精密测量的重要资源.Sagnac光纤环是制备简并关联光子对的典型装置,利用环中的对向传播光子对在50/50分束器的量子干涉,实现两个孪生简并关联光子的空间分离.本文利用两束不同波长的脉冲光抽运由300 m色散位移光纤和50/50分束器组成的Sagnac光纤环,通过环中单模光纤色散引入的相位差控制光子对的对向传播相位差,获取了空间模式分离的窄带简并关联光子对.Degenerate correlated photon pairs（DCPPs） have been widely used in quantum information science, especially in the areas of quantum computation, quantum state control and precision measurement, which are typically generated in a χ^（（2））nonlinear crystal through the spontaneous parametric down-conversion. However, such a source is not compatible with optical fiber as large coupling losses occur when the pairs are launched into it, which restricts its direct application to quantum information processing system. More recently, DCPP generation from spontaneous four-wave mixing in χ^（（3）） optical fiber has aroused strong interest, due to its advantages of compatibility with existing fiber networks and free of alignment. The process of generating DCPP in fiber can be described as follows： two pump photons at different frequencies ω_（p1） and ω_（p2） scatter through the χ^（（3）） nonlinearity to create a pair of identical photons at the mean frequencyωc, such that ω_（p1） ＋ ω_（p2） = 2ωc. Because the collinear tensor component χ_（xxxx）^（（3））in a Kerr nonlinear medium is 3 times as large as the tensor component χ_（xyxy）^（（3））, the co-polarized four-wave mixing is preferred, which means the two pump photons and new-born twin photons are both co-polarized. Therefore, it is very challenging to deterministically separate the fiber-based DCPP, since the twin photons share the same properties in all degrees of freedom： frequency, polarization and spatial. Sagnac fiber loop（SFL）, composed of a piece of nonlinear fiber and 50/50 coupler, is presented as the splitter for DCPP based on the reversed Hong-Ou-Mandel quantum interference of counter-propagating DCPPs. The SFL can be configured as a total reflector, total transmitter or equally transmissive and reflective state, which sets the differential phases of counter-propagating DCPPs meeting at 50/50 coupler to be π, 0 and-π, respectively. In order to satisfy the differential phase requirement fo

关 键 词：窄带简并关联光子对 Sagnac光纤环 自发四波混频 色散 

分 类 号：O431.2[机械工程—光学工程]