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Proceedings Paper

Fiber-coupled photonic crystal nanocavity for reconfigurable formation of coupled cavity system
Author(s): Tomohiro Tetsumoto; Yuta Ooka; Takasumi Tanabe
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Paper Abstract

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.

Paper Details

Date Published: 14 March 2016
PDF: 6 pages
Proc. SPIE 9756, Photonic and Phononic Properties of Engineered Nanostructures VI, 97561J (14 March 2016); doi: 10.1117/12.2212255
Show Author Affiliations
Tomohiro Tetsumoto, Keio Univ. (Japan)
Yuta Ooka, Keio Univ. (Japan)
Takasumi Tanabe, Keio Univ. (Japan)

Published in SPIE Proceedings Vol. 9756:
Photonic and Phononic Properties of Engineered Nanostructures VI
Ali Adibi; Shawn-Yu Lin; Axel Scherer, Editor(s)

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