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Method for calculating the coupling coefficient in step-index optical fibers.
Svetislav Savović1, Alexandar Djordjevich
1City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, China. savovic@kg.ac.yu
Applied Optics
|March 6, 2007
Summary
A new, simple method determines the mode coupling coefficient in multimode optical fibers by analyzing the far-field output pattern. This technique simplifies the characterization of optical fiber properties, aiding in understanding light propagation.
Area of Science:
- Optical physics and engineering
- Materials science of optical fibers
Background:
- Characterizing multimode optical fibers is crucial for understanding light propagation.
- Determining the mode coupling coefficient (D) is essential for predicting fiber behavior.
- Existing methods for measuring D can be complex and time-consuming.
Purpose of the Study:
- To propose a simplified method for measuring the mode coupling coefficient (D) in step-index multimode optical fibers.
- To demonstrate the method's applicability using a step-index plastic optical fiber.
- To validate the method by comparing calculated coupling and steady-state lengths with experimental data.
Main Methods:
- Observing the far-field output pattern of a single fiber length.
- Launching input light centrally along the fiber axis (theta(0)=0).
- Calculating the mode coupling coefficient (D) from the observed pattern.
Main Results:
- The proposed method provides a straightforward way to determine the mode coupling coefficient (D).
- Calculated coupling length (L(c)) and steady-state length (z(s)) showed good agreement with prior experimental results.
- The method simplifies the characterization of multimode optical fibers.
Conclusions:
- The simple method effectively determines the mode coupling coefficient (D) in step-index multimode optical fibers.
- This technique offers a practical approach for optical fiber characterization.
- The findings support the use of this method for analyzing light distribution in optical fibers.
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