Remote entanglement distribution of Yb:YVO₄ using free-space optical links

The integration of free-space optical (FSO) links with fiber-optic networks is a promising pathway for establishing flexible and scalable quantum communication channels and could enable satellite-based quantum links for future space-based entanglement distribution experiments. We are developing an approach to establish single-mode to single-mode fiber coupling using free-space optical links for remote entanglement distribution of REI solid-state qubits. The architecture is to perform a Bell-State measurement across the Caltech-to-JPL link with spin entangled photons from two Yb:YVO₄ nodes. A quantum frequency conversion (QFC) is being designed to standardize the qubit wavelength with telecom platforms and reduce atmospheric disturbances. The atmospheric turbulence and scintillation across the 10km link are characterized under varying weather conditions and are mitigated by employing adaptive optics and precise beam control. A phase controller system is also being implemented to account for phase mismatch of the photons. The simulated in lab coupling we are aiming for is -7dB with a current measured in lab efficiency of -10dB. This goal highlights the potential of using FSO links for future remote entanglement distribution and serves as the ground testbed for future space-based quantum links.