Zhong Tian, Wong Franco N C, Restelli Alessandro, Bienfang Joshua C
Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Opt Express. 2012 Nov 19;20(24):26868-77. doi: 10.1364/OE.20.026868.
We demonstrate generation of high-purity photon pairs at 1560 nm in a single spatial mode from a periodically-poled KTiOPO4 (PPKTP) waveguide. With nearly lossless spectral filtering, the PPKTP waveguide source shows approximately 80 % single-mode fiber coupling efficiency and is well suited for high-dimensional time-energy entanglement-based quantum key distribution. Using high-count-rate self-differencing InGaAs single-photon avalanche photodiodes configured with either square or sinusoidal gating, we achieve > 1 Mbit/s raw key generation with 3 bits-per-photon encoding, and, to the best of our knowledge, the highest reported Franson quantum-interference visibility of 98.2 % without subtraction of accidental coincidences.
我们展示了在周期性极化磷酸钛氧钾（PPKTP）波导中，于单一空间模式下产生1560纳米的高纯度光子对。通过近乎无损的光谱滤波，PPKTP波导源展现出约80%的单模光纤耦合效率，非常适合基于高维时间 - 能量纠缠的量子密钥分发。使用配置有方形或正弦门控的高计数率自差分铟镓砷单光子雪崩光电二极管，我们实现了采用每光子3比特编码的超过1 Mbit/s的原始密钥生成，并且据我们所知，在不扣除偶然符合事件的情况下，实现了高达98.2%的最高报道的弗兰森量子干涉可见度。
