Analysis and Design of Low-Loss and Fast All-Optical Switch Elements on Silicon Nitride for Integrated Quantum Photonics

Fabian Ruf, Lars Nielsen, Nicolas Volet, Martijn Heck

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review


Fast and ultra-low loss single-photon switching and routing are essential for photonic quantum computation and communication. To address this need in a scalable fashion, all-optical switches that can be fabricated in an ultra-low loss and mature Si3N4 photonic integrated circuit (PIC) foundry platform are designed and optimized for sub-ns switching times suitable for deterministic quantum-dot single-photon sources. The working principle relies on cross-phase modulation (XPM) of the single photons with a 1550-nm pump pulse and is enhanced by a ring resonator. Two different designs of the primary switch element are theoretically studied, namely a ring resonator intensity switch (RRIS) based on resonance shifting due to XPM and a ring resonator phase switch (RRPS) acting as an all-optical phase shifter in a Mach–Zehnder interferometer. As a novel approach to speed up the switching, chirped pre-emphasis and wipe sections for the pump pulses are utilized. A design tool is established from analytical expressions and serves as starting point for further optimization using a dedicated travelling-wave model (TWM). The TWM demonstrates the feasibility of both designs to be driven by either the proposed pre-emphasis pulse shape or a train of chirped Gaussian pulses. While the RRPS turns out to require less pump energy, its operation is more sensitive to pump-power fluctuations. Insertion losses below 0.1dB and a power consumption below 5nJ at 1GHz switching rates for both configurations prove the potential of this concept for scalable quantum photonic applications.
Original languageEnglish
JournalJournal of Lightwave Technology
Pages (from-to)7598-7609
Number of pages12
Publication statusPublished - Dec 2022


  • Bandwidth
  • Optical interferometry
  • Optical losses
  • Optical ring resonators
  • Optical switches
  • Photonics
  • Quantum photonics
  • Silicon nitride
  • all-optical switching
  • integrated photonics
  • integrated quantum photonics
  • optical Kerr effect
  • photonic integrated circuits
  • silicon nitride


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