Actually the limit predicted by Shannon can be significantly beaten, because Shannon assumes gaussian noise, but if we use photon counting receivers we need to use a poisson distribution. This is the Gordon-Holevo limit.
To beat Shannon you need PPM formats and photon counters (single photon detectors).
One can do significantly better than the numbers from voyager in the article using optics even without photon cpunting. Our group has shown 1 photon/bit at 10 Gbit/s [1] but others have shown even higher sensitivity (albeit at much lower data rates).
To beat Shannon you need PPM formats and photon counters (single photon detectors).
One can do significantly better than the numbers from voyager in the article using optics even without photon cpunting. Our group has shown 1 photon/bit at 10 Gbit/s [1] but others have shown even higher sensitivity (albeit at much lower data rates).
[1] https://www.nature.com/articles/s41377-020-00389-2