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Applied Optics

Applied Optics


  • Vol. 39, Iss. 13 — May. 1, 2000
  • pp: 2029–2037

Propagation of light trapped within a set of lowest-order modes of graded-index multimode fiber undergoing bending

Charles K. Asawa and Henry F. Taylor  »View Author Affiliations

Applied Optics, Vol. 39, Issue 13, pp. 2029-2037 (2000)

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We describe experimental results and a theoretical analysis for propagation in graded-index multimode fiber when diode laser light is launched into the lowest-order propagation modes and the fiber undergoes severe bending perturbations. Experimentally, near-field modal interference images and transmission loss measurements were obtained for different loop diameters. The data indicate that, when the fundamental mode is excited, the light remains in lowest-order modes even for small bend diameters. This is consistent with analysis which predicts that, in a parabolic-index multimode fiber subject to constant diameter bending, the light tends to oscillate between lowest-order modes and remains trapped therein rather than diffusing to high-order modes. Implications of these results for an intrusion-resistant communication system with graded-index multimode fiber are discussed.

© 2000 Optical Society of America

OCIS Codes
(060.2300) Fiber optics and optical communications : Fiber measurements
(060.2310) Fiber optics and optical communications : Fiber optics

Original Manuscript: July 30, 1999
Revised Manuscript: January 17, 2000
Published: May 1, 2000

Charles K. Asawa and Henry F. Taylor, "Propagation of light trapped within a set of lowest-order modes of graded-index multimode fiber undergoing bending," Appl. Opt. 39, 2029-2037 (2000)

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