Bragg grating induced cladding mode coupling due to asymmetrical index modulation in depressed cladding fibers

Martin Ole Berendt, Lars Grüne-Nielsen, C.F. Soccolich, Anders Overgaard Bjarklev

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    Abstract

    UV-written Bragg gratings find wide spread use as wavelength selective components. In reflection high extinction ratios are routinely obtained. However, coupling to cladding modes gives excess loss on the short wavelength side of the main reflection. Different fiber-designs have been proposed to reduce this problem. None of these designs seems to give complete solutions. In particular, the otherwise promising depressed cladding design gives a pronounced coupling to one LP01 mode, this has been referred to as a Ghost grating. To find the modes of the fiber we have established a numerical mode-solver based on the staircase-approximation method. The Bragg grating causes coupling between the fundamental LP01 mode and higher order LP1p modes that satisfy phase-matching. The coupling strength is determined by the overlap integral of the LP01, the LP1p mode, and the UV-induced index perturbation. For LP0n the index perturbation is set to one in the core and zero elsewhere. For LP1n it is simplified to the worst case, i.e., opposite sign of the field
    Original languageEnglish
    Title of host publicationTechnical Digest Optical Fiber Communication Conference and Exhibit
    PublisherIEEE
    Publication date1998
    Pages7-8
    ISBN (Print)1-55752-521-8
    DOIs
    Publication statusPublished - 1998
    Event1998 Optical Fiber Communication Conference and Exhibit - San Jose, CA, United States
    Duration: 22 Feb 199827 Feb 1998
    http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=5284

    Conference

    Conference1998 Optical Fiber Communication Conference and Exhibit
    CountryUnited States
    CitySan Jose, CA
    Period22/02/199827/02/1998
    Internet address

    Bibliographical note

    Copyright 1998 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.

    Cite this

    Berendt, M. O., Grüne-Nielsen, L., Soccolich, C. F., & Bjarklev, A. O. (1998). Bragg grating induced cladding mode coupling due to asymmetrical index modulation in depressed cladding fibers. In Technical Digest Optical Fiber Communication Conference and Exhibit (pp. 7-8). IEEE. https://doi.org/10.1109/OFC.1998.657157