Leakage of the fundamental mode in photonic crystal fiber tapers

Hong C. Nguyen*, Boris T. Kuhlmey, Michael J. Steel, Cameron L. Smith, Eric C. Mägi, Ross C. McPhedran, Benjamin J. Eggleton

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


We report detailed measurements of the optical properties of tapered photonic crystal fibers (PCFs). We observe a striking long-wavelength loss as the fiber diameter is reduced, despite the minimal airhole collapse along the taper. We associate this loss with a transition of the fundamental core mode as the fiber dimensions contract: At wavelengths shorter than this transition wavelength, the core mode is strongly confined in the fiber microstructure, whereas at longer wavelengths the mode expands beyond the microstructure and couples out to higher-order modes. These experimental results are discussed in the context of the so-called fundamental mode cutoff described by Kuhlmey et al. [Opt. Express 10, 1285 (2002)], which apply to PCFs with a finite microstructure.

Original languageEnglish
Pages (from-to)1123-1125
Number of pages3
JournalOptics Letters
Issue number10
Publication statusPublished - 15 May 2005
Externally publishedYes


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