Fiber-coupled photonic crystal nanocavity for reconfigurable formation of coupled cavity system

Tomohiro Tetsumoto, Yuta Ooka, Takasumi Tanabe

    Research output: Chapter in Book/Report/Conference proceedingConference contribution


    High Q optical cavities are employed to realize a coupled cavity system with which to achieve optical signal processing. Photonic crystal (PhC) nanocavities are particularly attractive because they are suitable for integration. However, they usually suffer from low coupling efficiency with optical fiber and poor resonant wavelength controllability. We recently demonstrated cavity mode formation by placing a tapered nanofiber close to a two-dimensional photonic crystal waveguide. The cavity mode couples directly with the nanofiber, which results in a coupling efficiency of 39% with a high Q of over half a million. The cavity is formed due to the modulation of the effective refractive index, which is caused by bringing a nanofiber close to the silicon slab. Precise tuning of the resonant wavelength becomes possible by changing the contact area of the nanofiber. In this study, we demonstrate the coupling and de-coupling of coupled PhC nanocavities formed by a nanofiber placed on a PhC waveguide. The wavelength shift of one of the cavities (mode A) is more sensitive than that of the other cavity (mode B) to a change in the nanofiber contact area. By using this difference, we can tune the resonant wavelength of mode A (Q = 4.6×105) to that of mode B (Q = 6.0×105). Then, a clear anti-crossing with a mode splitting of g/2π = 0.94 GHz is observed, which is the result of the coupling of the two modes. A reconfigurable coupled cavity system was demonstrated.

    Original languageEnglish
    Title of host publicationPhotonic and Phononic Properties of Engineered Nanostructures VI
    ISBN (Electronic)9781628419917
    Publication statusPublished - 2016
    EventPhotonic and Phononic Properties of Engineered Nanostructures VI - San Francisco, United States
    Duration: 2016 Feb 152016 Feb 18


    OtherPhotonic and Phononic Properties of Engineered Nanostructures VI
    Country/TerritoryUnited States
    CitySan Francisco


    • coupled cavity
    • micro-and nanocavity
    • nanofiber
    • Photonic crystal

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics
    • Computer Science Applications
    • Electrical and Electronic Engineering
    • Applied Mathematics


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