A team led by Prof. Guo Guangcan from University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) and collaborators first realized distribution of high-dimensional orbital angular momentum entanglement over a 1 km few-mode fiber. The result is published in Optica.
Source:
https://phys.org/news/2020-03-one-kilometer-breakthrough-quantum-field.html