400%/W second harmonic conversion efficiency in 14 μm-diameter gallium phosphide-on-oxide resonators.

Second harmonic conversion from 1550 nm to 775 nm with an efficiency of 400% W is demonstrated in a gallium phosphide (GaP) on oxide integrated photonic platform. The platform consists of doubly-resonant, phase-matched ring resonators with quality factors Q ∼ 10, low mode volumes V ∼ 30(λ/n), and high nonlinear mode overlaps. Measurements and simulations indicate that conversion efficiencies can be increased by a factor of 20 by improving the waveguide-cavity coupling to achieve critical coupling in current devices.

Frequency Control of Single Quantum Emitters in Integrated Photonic Circuits.

Generating entangled graph states of qubits requires high entanglement rates with efficient detection of multiple indistinguishable photons from separate qubits. Integrating defect-based qubits into photonic devices results in an enhanced photon collection efficiency, however, typically at the cost of a reduced defect emission energy homogeneity. Here, we demonstrate that the reduction in defect homogeneity in an integrated device can be partially offset by electric field tuning.