A global quantum network is an important piece of infrastructure for a number of quantum technologies. This includes technologies such as provably secure communications through quantum key distribution, and distributed quantum computing. Constructing a global quantum network will likely require a number of separate quantum technologies such as microwave to optical interconnects, quantum memories, and quantum processors. Rare-earth ions doped into crystals are promising materials for developing such quantum technologies because of their long coherence times and narrow optical line widths. Erbium is of particular interest due to its 1530-1540nm optical transition in the fiber-optic telecommunications C-band.

I will present an overview of my group’s research studying rare-earth ion crystals to develop technologies for quantum networks. In particular, I will discuss our research into using europium doped crystal to improve crystal field models for the rareearth ions, a material study of erbium implanted in silicon, optical-microwave transduction using stoichiometric erbium crystals, and the development of a telecom-compatible quantum memory using a dilute erbium doped crystal.