Interaction-free quantum optical fredkin gates in χ (2) Microdisks

Yu Ping Huang*, Prem Kumar

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


We present novel interaction-free realizations of quantum optical Fredkin gates that do not rely on direct physical coupling between the target light (signal) and the control light (pump). The interaction-free feature of such gates allow to overcome the fundamental limits of photon loss and quantum-state decoherence imposed by the signal-pump coupling. This advantage, together with the low inherent quantum-noise level in χ (2) microdisks, gives rise to substantially improved performance over the existing Fredkin-gate designs. Explicitly using lithium-niobate mircrodisks, we present two kinds of interaction-free Fredkin gates, a phase gate and an optical-path gate, both of which are designed with telecom-band applications in mind. For both gates, the threshold pump peak power to achieve a gate contrast >100 and a signal loss <10% is hundreds of microwatts for practical parameters of the devices.

Original languageEnglish (US)
Article number5740561
Pages (from-to)600-611
Number of pages12
JournalIEEE Journal on Selected Topics in Quantum Electronics
Issue number2
StatePublished - 2012


  • Fredkin gate
  • lithium niobate
  • microdisk

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering


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