利用高非线性光纤产生量子关联光子对的实验研究

Experimental Investigations on Producing Quantum Correlated Photon Pairs in High Nonlinear Fiber

光纤中基于三阶(克尔)非线性效应的自发四波混频是制备量子关联光子对的有效方法之一。若采用商售高非线性光纤作为产生光子对的非线性介质,则有利于减小所需光纤的长度,从而缩小实验装置体积并降低对于抽运源的要求。利用脉冲光抽运20m的高非线性光纤产生通讯波段的频率近简并关联光子对,研究了光纤的弱双折射特性对于光子对产生的影响。当抽运光沿高非线性光纤的偏振轴入射时,具有最大的光子对产生效率,且光子对绝大部分与抽运光偏振平行;抽运光沿与光纤偏振轴45°入射时,光子对的产生效率最小,约为最大值的80%。

Spontaneous four-wave mixing originated from third-order（Kerr） nonlinear effect in fiber,is an efficient way to produce quantum correlated photon pairs.If the commercially available high-nonlinear fiber can be used as the Kerr nonlinear medium,it will be beneficial for simplifying the experimental setup,because the length of fiber and power of pump can be reduced.Near-degenerate photon pairs in telecom band are produced in 20 m-long high nonlinear fiber by pulsed laser.The influence of weak-birefringence of high nonlinear fiber upon the production efficiency of photon pairs is experimentally investigated and analyzed.When the polarization of pump is along the fast or slow axis of the high nonlinear fiber,the production efficiency of photon pairs is maximal,and photon pairs are co-polarized with the pump;when the polarization of pump is along the 45° in respect to the fast axis,the production efficiency of photon pairs is minimal,which is about 80% of maximum.