Photonic qubit technologies using lithium niobate

Transmission and processing of quantum information using light has been pursued for decades. As other systems for manipulating quantum information have also flourished, light continues to have a key role in quantum science and technology, as exemplified by the 2022 Nobel prize in physics. Some of the advantages of light-based qubits are room-temperature operation and transmission of information at high rates and long distances. Optical nonlinearities in solid-state crystals have been a workhorse of optical quantum information science, with lithium niobate standing out due to its combination of low loss, large second-order optical and electro-optic effects, and recently, its ability to be lithographically patterned and etched to form nanoscale devices in integrated circuits. We discuss joint work between Caltech, Fermilab and the Jet Propulsion Lab on quantum photonics experiments for quantum networks using commercially available fiber-coupled lithium niobate devices while also describing work towards integrating these experiments using the thin-film lithium niobate platform developed at Harvard university. Finally, we describe new quantum photonics devices enabled by this platform, touching on their impact for next-generation quantum technology.