Low-loss all-optical ns-switching for single-photon routing in scalable integrated quantum photonics

Fabian Ruf*, Lars Nielsen, Mircea Balauroiu, Nicolas Volet, Martijn Heck

*Corresponding author for this work

Research output: Contribution to book/anthology/report/proceedingArticle in proceedingsResearch


Efficient single-photon routing and switching are crucial for optical quantum computing and communication. For this purpose, all-optical switches are designed for gigahertz bandwidths. The switching mechanism is based on the optical Kerr effect via cross-phase modulation (CPM) of the single-photon signal by a strong 1550-nm pump pulse. For energy-efficient switching, this nonlinear effect is exploited in a microresonator that can either be used directly as an intensity switch in a typical add–drop configuration or as a phase shifter in a Mach–Zehnder interferometer (MZI) structure. To speed up resonance build-up and quenching, a pre-emphasis build and an off-resonance wipe pulse are used. The proposed designs are verified by traveling-wave simulations which demonstrate that 0.1 dB insertion loss and ~1 ns switching windows can be achieved. For a scalable out-of-the-lab transfer, we investigate the feasibility of the proposed switch designs for fabrication in a mature photonic integrated circuit (PIC) platform. In particular, silicon nitride PICs have demonstrated record-low losses which makes them suitable for single-photon applications. By parametric modelling of the microresonator’s directional couplers based on Lumerical EME and 2.5-dimensional varFDTD simulations, the required power transmission coefficients for both signal and pump wavelength can be achieved. This results in an all-optical switch design ready for fabrication in a commercial PIC foundry which can potentially enable scalable architectures for quantum photonic applications.
Original languageEnglish
Title of host publicationIntegrated Photonics Platforms II
Editors Roel G. Baets, Peter O'Brien, Laurent Vivien
Place of publication Bellingham
PublisherSPIE - International Society for Optical Engineering
Publication dateMay 2022
Article number12148-6
ISBN (Print) 9781510651722
ISBN (Electronic)9781510651722
Publication statusPublished - May 2022
EventSPIE Photonics Europe - Strasbourg, France
Duration: 3 Apr 20217 Apr 2022


ConferenceSPIE Photonics Europe
SeriesProceedings of SPIE, the International Society for Optical Engineering


  • all-optical switching
  • microresonator
  • nonlinear effects
  • optical Kerr effect
  • photonic integrated circuits
  • quantum photonic applications
  • silicon nitride
  • single photons


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