(AnalyticsInsight) A team of Chinese researchers has been able to link quantum memories extending up to 22 km of optic fiber using two-photon interference techniques and to 50 km using single-photon interference. Thus beating the previous record by more than 40 times over. This achievement comes from collaboration by scientists at University of Science and Technology of China (USTC; Hefei, China), the Jinan Institute of Quantum Technology (Jinan, China), and the Shanghai Institute of Microsystem and Information Technology (SIMIT) at the Chinese Academy of Sciences (Shanghai, China). Their work has brought us closer to a super-fast, super-secure quantum internet that shall dominate network connectivity in the future. It also exhibits a shorter entanglement creation time (150 and 0.65 seconds, respectively, compared to 1300 seconds) with better quantum link efficiency.
The experiment was simple. In their published article on Nature, the team mentioned that they used difference frequency generation (DFG) in a lithium niobate waveguide to shift the near-infrared photons to the telecommunications O band (centered at 1342 nm) to enable a low-loss transmission in standard optical fibers. This was to prevent the absorption of the photons in the optical fiber.

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