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arXiv · 1811.11741

Unidirectional frequency conversion in microring resonators for on-chip frequency-multiplexed single-photon sources

Mikkel Heuck·Jacob Gade Koefoed·Jesper Bjerge Christensen·Yunhong Ding·Lars Hagedorn Frandsen·Karsten Rottwitt·Leif Katsuo Oxenlowe
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Abstract

Microring resonators are attractive for low-power frequency conversion via Bragg-scattering four-wave-mixing due to their comb-like resonance spectrum. However, conversion efficiency is limited to 50% due to the equal probability of up- and down-conversion. Here, we demonstrate how two coupled microrings enable highly directional conversion between the spectral modes of one of the rings. An extinction between up- and down-conversion of more than 40 dB is experimentally observed. Based on this method, we propose a design for on-chip multiplexed single-photon sources that allow localized frequency modes to be converted into propagating continuous-mode photon wave packets using a single operation. The key is that frequency conversion works as a switch on both spatial and spectral degrees of freedom of photons if the microring is interferometrically coupled to a bus waveguide. Our numerical results show 99% conversion efficiency into a propagating mode with a wave packet having a 90% overlap with a Gaussian for a ratio between intrinsic and coupling quality factors of 400.

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Mikkel Heuck, Jacob Gade Koefoed, Jesper Bjerge Christensen, Yunhong Ding, Lars Hagedorn Frandsen, Karsten Rottwitt, Leif Katsuo Oxenlowe. 2018-11-28. Unidirectional frequency conversion in microring resonators for on-chip frequency-multiplexed single-photon sources. https://doi.org/10.1088/1367-2630%2Fab09a7

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