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Pulse broadening caused by deviations from the optimal index profile.
Applied Optics
|February 19, 2010
Summary
Deviations in multimode optical fiber index profiles significantly increase pulse broadening. Narrower index profile bumps and specific oscillating perturbations have the greatest impact, requiring precise profile control.
Area of Science:
- Optical Fiber Communications
- Materials Science and Engineering
Background:
- Multimode optical fibers are crucial for data transmission.
- Deviations from the ideal refractive index profile cause signal distortion, specifically pulse broadening.
- Controlling these deviations is key to maintaining signal integrity.
Purpose of the Study:
- To analyze excess pulse broadening in multimode optical fibers due to index profile deviations.
- To quantify the impact of specific types of index perturbations on pulse broadening.
- To establish guidelines for refractive index profile control.
Main Methods:
- Utilized first-order perturbation theory to model index profile variations.
- Assessed perturbations with low longitudinal spatial frequencies that do not induce mode coupling.
- Developed a simplified expression for excess pulse broadening using a weighting function integral.
Main Results:
- Analyzed Gaussian-shaped index bumps/dips and oscillating perturbations.
- Found that narrower bumps and those at larger core radii significantly increase pulse broadening.
- Identified that 2-18 radial oscillations cause significant broadening, while faster oscillations have negligible effects.
Conclusions:
- Specific refractive index profile perturbations critically affect pulse broadening in multimode fibers.
- Precise control over the shape, width, and radial oscillations of the index profile is necessary.
- Results inform manufacturing processes to minimize signal distortion and ensure high-speed data transmission.
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