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Updated: Jun 7, 2026
09:19
Fabrication and Characterization of Disordered Polymer Optical Fibers for Transverse Anderson Localization of Light
Published on: July 29, 2013
Mode coupling in large-diameter polymer-clad silica fibers
Applied Optics
|November 2, 2010
Summary
Intermodal diffusion in plastic-clad silica fibers follows a 1/θ(2) dependence, with a diffusion constant of 1.3 × 10⁻⁵ rad² m⁻¹. This impacts evanescent-wave spectroscopy by slightly reducing external evanescent power.
Area of Science:
- Optical Physics
- Materials Science
- Fiber Optics
Background:
- Intermodal diffusion is crucial for understanding light propagation in optical fibers.
- Plastic-clad silica (PCS) fibers offer unique properties for various applications.
- Evanescent-wave spectroscopy relies on the interaction of light with the fiber cladding.
Purpose of the Study:
- To quantify intermodal diffusion in large-diameter PCS step-index fibers.
- To determine the relationship between diffusion and mode properties.
- To assess the impact of diffusion on evanescent-wave spectroscopy.
Main Methods:
- Near-field projection of modal patterns onto a CCD camera to measure diffusion.
- Analysis of modal patterns to determine the 1/θ(2) dependence.
- Calculation of the diffusion constant.
Main Results:
- Intermodal diffusion was measured and found to follow a 1/θ(2) dependence.
- The diffusion constant was determined to be 1.3 × 10⁻⁵ rad² m⁻¹.
- Diffusion causes a maximum 10% reduction in external evanescent-wave power for a 0.4 numerical aperture fiber.
Conclusions:
- The study provides a quantitative understanding of intermodal diffusion in PCS fibers.
- Mode mixing due to diffusion has a measurable but limited effect on evanescent-wave spectroscopy.
- Findings are relevant for optimizing fiber optic sensing and spectroscopy applications.
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