Long-distance entanglement distribution is essential both for foundational tests of quantum physics and scalable quantum networks. Owing to channel loss, however, the previously achieved distance was limited to ~100 km. Here, we demonstrate satellite-based distribution of entangled photon pairs to two locations separated by 1203 km on the Earth, through satellite-to-ground two-downlink with a sum of length varies from 1600 km to 2400 km. We observe a survival of two-photon entanglement and a violation of Bell inequality by 2.37+/-0.09 under strict Einstein locality conditions. The obtained effective link efficiency at 1200 km in this work is over 12 orders of magnitude higher than the direct bidirectional transmission of the two photons through the best commercial telecommunication fibers with a loss of 0.16 dB/km.
@article{arxiv.1707.01339,
title = {Satellite-Based Entanglement Distribution Over 1200 kilometers},
author = {Juan Yin and Yuan Cao and Yu-Huai Li and Sheng-Kai Liao and Liang Zhang and Ji-Gang Ren and Wen-Qi Cai and Wei-Yue Liu and Bo Li and Hui Dai and Guang-Bing Li and Qi-Ming Lu and Yun-Hong Gong and Yu Xu and Shuang-Lin Li and Feng-Zhi Li and Ya-Yun Yin and Zi-Qing Jiang and Ming Li and Jian-Jun Jia and Ge Ren and Dong He and Yi-Lin Zhou and Xiao-Xiang Zhang and Na Wang and Xiang Chang and Zhen-Cai Zhu and Nai-Le Liu and Yu-Ao Chen and Chao-Yang Lu and Rong Shu and Cheng-Zhi Peng and Jian-Yu Wang and Jian-Wei Pan},
journal= {arXiv preprint arXiv:1707.01339},
year = {2017}
}