脉冲抽运光啁啾对全光纤量子关联光子对纯度的影响

信号与闲置光子波长均为1550 nm 通信波段的全光纤关联光子对源, 具有低成本以及可与现有光纤网络低损耗连接的特点. 进一步优化其纯度, 将有助于提高这种量子光源的实用化程度.当抽运脉冲光在光纤中传输时, 由于色散和Kerr非线性效应的影响, 会不可避免地引入啁啾. 本文利用脉冲激光抽运零色散位移光纤, 研究了抽运光啁啾对关联光子对纯度的影响. 结果表明, 通信波段小失谐关联光子对的纯度随啁啾的增大而下降. 若采用变换极限的锁模激光为抽运源, 将有助于抑制Raman散射对自发四波混频的影响, 提高光子对的纯度. 关键词： 关联光子对 光纤 自发四波混频 啁啾

Influence of pump chirp on the purity of an all fiber source of correlated photon pairs*

The all fiber sources of photon pairs in the 1550 nm telecom band have the advantages of low cost and compatibility with the fiber network. Further improving the purity will improve the practicality of the quantum light sources. For the pulsed pump field propagating through the optical fiber, a certain amount of chirp will be inevitably induced due to the effects of chromatic of dispersion and Kerr nonlinearity, but its influence on the purity has not been studied yet. In this paper, using photon pairs produced by the spontaneous four wave mixing in dispersion shifted fiber, we study the influence of pump chirp on the purity of photon pairs by varying the chirp of the pulsed pump. For the pump with a given bandwidth, our results demonstrate that the purity of photon pairs having a certain production rate, decreases with the increase of the absolute quantity of pump chirp. Therefore, the purity of the photon pairs with relatively small detuning can be improved by using the transform limited pump pulses due to the suppressed Raman scattering.
Keywords： photon-pairs fiber spontaneous four-wave mixing chirp