Characterization of near-infrared to telecom frequency conversion in a rubidium-filled hollow-core photonic-crystal fiber

We experimentally investigate near-infrared to telecommunications frequency conversion via a diamond four-wave mixing scheme in rubidium vapor contained within a hollow-core photonic-crystal fiber. The strong light-atom interaction in the fiber results in lower pump power requirements and higher conversion efficiency than can be achieved under equivalent conditions in a rubidium vapor cell. We also observe non-intuitive pump and signal frequency dependence of the four-wave mixing efficiency in the fiber due to the large nonlinearities present in the system. These results indicate the potential for hollow-core fibers to provide a scalable solution for quantum information network infrastructure, with additional modelling required for a full understanding of the extreme atom-light interaction effects present.