Multi-dimensional entanglement transport through single-mode fibre

Understand

The global quantum network requires the distribution of entangled states over long distances, with significant advances already demonstrated using entangled polarisation states, reaching approximately 1200 km in free space and 100 km in optical fibre.

• Packing more information into each photon requires Hilbert spaces with higher dimensionality, for example, that of spatial modes of light.
• However spatial mode entanglement transport requires custom multimode fibre and is limited by decoherence induced mode coupling.
• Here we transport multi-dimensional entangled states down conventional single-mode fibre (SMF).