两个独立全光纤多通道光子纠缠源的Hong-Ou-Mandel干涉  

Hong-Ou-Mandel interference between two independent all-fiber multiplexed photon sources

作　　者：李银海[1] 许昭怀 王双[2,3] 许立新[1] 周志远[2,3] 史保森[2,3] 

机构地区：[1]中国科学技术大学光学与光学工程系,合肥230026 [2]中国科学技术大学中国科学院量子信息重点实验室,合肥230026 [3]中国科学技术大学量子信息和量子物理协作创新中心,合肥230026

出　　处：《物理学报》2017年第12期49-55,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11174271;61275115;61435011;61525504);中央高校基本科研业务费专项资金(批准号:WK2030380009)资助的课题~~

摘　　要：独立光子源的干涉是实现复杂量子体系应用(比如多光子纠缠态产生和量子隐形传态等)的核心技术.利用100 GHz密集波分复用技术,实现了1.55μm全光纤多通道独立纠缠光子源的Hong-Ou-Mandel干涉,在不去除暗符合(随机符合计数)的情况下,可见度为53.2%±8.4%,去除暗符合可见度可达到82.9%±5.3%.给出了关于色散位移光纤中基于自发四波混频过程产生的单光子光谱纯度严格的理论描述,模拟了抽运脉冲宽度和滤波器带宽对单光子光谱纯度的影响,并给出了理论上的最佳条件(最佳的抽运脉冲宽度为8 ps,高斯滤波器带宽为40 GHz及以下).在测量Hong-Ou-Mandel干涉之前,先测量了液氮冷却状态下的色散位移光纤关联光子源的符合和随机符合比率,在抽运功率为23μW的情况下,最大比率可以达到131.Hong-Ou-Mandel干涉在高精度光学测量、测量装置无关的量子密钥分配等应用中扮演着极为重要的角色.Interference between independent photon sources is the key technique to realize complex quantum systems for more sophisticated applications such as multi-photon entanglement generation and quantum teleportation. Here, we report Hong-Ou-Mandel interference （HOMI） between two independent 1.55 μm all-fiber photon pair sources over two 100 GHz dense wave division multiplexing （DWDM） channels, whose visibility reaches 53.2% ± 8.4% （82.9% ± 5.3%） without （with） back ground counts subtracted. In addition, we theoretically describe in detail the single photon spectral purity of the photon source generated in dispersion shifted fiber （DSF）, simulate the influences of the pulse width and filter bandwidth on the purity, and obtain the optimized condition. The optimized pump pulse width is 8 ps and filter bandwidth is about 40 GHz or less. A home-made 1550.1 nm mode-locked fiber laser source, whose pulse width and repetition rate are 25 ps and 27.9 MHz respectively, acts as a pump of photon source. A tunable attenuator is used to adjust the pump power of the photon source, and the broad band background fluorescence photons are filtered out by cascade 100 GHz DWDM filters. The clean pump beam is divided into two equal parts by the 50 ： 50 optical coupler to pump two 300 m DSFs （cooled by liquid nitrogen） to generate independent photon sources. Then the strong pump beam and noise photon from Raman scattering in orthogonal polarization are removed by 2 groups of 200 GHz DWDM filters and fiber polarization rotator and polarizer. Then two 100 GHz DWDMs are used for separating photons at correlated channel pairs. The relative delay between the two independent photons is adjusted by tunable fiber delay line. Photons from the same channels are combined in a second beam splitter for interference, and the other two photons are used as trigger signals. The two triggered photons are detected by two free running InGaAs avalanched single photon detectors （APD1, APD4, ID Quanta, ID220, 20% detection efficienc

关 键 词：密集波分复用 Hong-Ou-Mandel干涉 色散位移光纤 

分 类 号：O431.2[机械工程—光学工程]