Integration of single photons from a trapped ion in a programmable photonic circuit

Trapped ions are one of the most promising quantum memories for scalable quantum networks and quantum computing. They can emit single photons entangled with ion’s spin states making them a promising choice to implement quantum networks. So far, bulks optics are being used to establish optical interconnects between trapped ions which lacks scalability. To establish long-distance quantum networks in a scalable way, we need to route single photons from trapped ions into integrated photonic circuits and switch them on-demand into different photonic channels. However, every trapped ion has strong dipole transitions in ultra-violet and visible wavelength and emits single photons in that regime making them incompatible for present-day photonic foundry. In this work, we route the single photons from a trapped barium ion in the silicon-nitride integrated photonic circuit.  For this integration, we first generate C-band telecom single photons from barium ions.  Using the thermo-optic property of silicon-nitride, we then switch the single photons in different channels of a Mach-Zehnder interferometer controlling the current of the phase-shifter. These results will enable a new generation of compact and reconfigurable integrated photonic devices that can serve as efficient quantum interconnects for quantum computers and sensors.