Fundamental Characteristics of Localized Acoustic Modes in Photonic Crystal Fibers

Ikumi ENOMORI  Kunimasa SAITOH  Masanori KOSHIBA  

IEICE TRANSACTIONS on Electronics   Vol.E88-C    No.5    pp.876-882
Publication Date: 2005/05/01
Online ISSN: 
DOI: 10.1093/ietele/e88-c.5.876
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Joint Special Section on Recent Progress in Optoelectronics and Communications)
Category: Optical Fibers, Cables and Fiber Devices
photonic crystal fiber,  photonic band-gap,  acoustic wave,  acoustic band-gap,  acousto-optic effect,  

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Propagation characteristics of acoustic waves in photonic crystal fibers (PCFs) have been theoretically investigated in details. In order to evaluate acoustic band structures and guided modes for out-of-plane propagation in PCFs, analysis methods based on the finite element method are newly formulated. It is shown through numerical results that complete acoustic band-gaps (ABGs) exist in the cladding region of PCFs and that acoustic guided modes could be localized in the defect region of PCFs by the ABG effect. Furthermore, it is shown that acoustic guided modes could also be localized in the defect region of PCFs by the total internal reflection. These confinement mechanisms of acoustic waves propagating along the fiber length are completely different to those of lightwaves.