Activity: Talk or presentation › Oral presentation
Quantum communication offers a secure method to transmit information. Current methods suffer from the need of preparing single-photon Fock states or weak coherent pulses with less than one photon, forming a bottleneck for practical realization. Here we propose and experimentally demonstrate a novel secure quantum communication scheme as shown in the figure. It employs the spatial modes in multimode fibers and is secure for weak coherent pulses. A high-dimensional alphabet is generated by wavefront shaping at the output facet of the receiver allowing direct decoding of messages. Since Eve cannot physically reproduce the complex structure of the long stretch of distorted multimode fiber under Bob’s control, she will see a randomized wavefront and therefore can’t extract all information. The use of low-loss optical fibers allows large-distance secure communication.