An integrated fiber-based cavity in a Paul trap

A segmented micro-structured linear Paul trap with an integrated fiber-based cavity is constructed, with the aim of investigating long-distance entanglement distribution. The fiber-based cavity was fabricated at the beginning of this thesis, in order to build a high-finesse cavity of length ≤ 250 µm, and with a finesse of up to F = 16000. The cavity is supported on a compact, monolithic holder design. The trap design has been adapted from a segmented ion trap to allow resonator integration. The chips feature vertical interconnects (VIAs) that allow for application of voltages ≤ 800 V peak-peak. The resonator-trap-system was successfully operated and characterized. However, we were not able to show the ion interacting with the cavity field, and conjecture stray charges which strongly modify the electric axial trapping potential. The strength of the charges required to create this effect is quantified. Furthermore, the setup is investigated regarding the feasibility of implementing a selection of quantum key distribution protocols. Experimentally achievable parameter assumptions lead to calculated rates of more than than 100 entanglements per second for non-local Bell state fidelities ≤ 0.95 with the existing platform. Limiting parameters are identified, and it is concluded that entanglement generation rates of 750 s${}^{-1}$ at fidelities of 0.95 are within reach with current technology. These rates exceed the stationary qubit decay rate, and allow the creation of high-fidelity, non-local entanglement. This work is thus an important step towards realizing long-range entanglement distribution based on ion traps.