Ray theory of randomly bent multimode optical fibers

Area of Science:

• Optics
• Photonics
• Fiber Optics

Background:

• Light propagation in optical fibers is crucial for telecommunications.
• Understanding multimode optical fibers with random bends is complex.
• Existing modal theories have limitations regarding mode coupling assumptions.

Purpose of the Study:

• To provide a comprehensive solution for light propagation in randomly bent, circularly symmetric multimode optical fibers.
• To develop a method that bypasses the assumptions of traditional modal theories.
• To effectively account for coupling between nonadjacent modes.

Main Methods:

• Utilizing the paraxial-ray-optics approximation.
• Developing a ray-optics solution.
• Comparing the ray-optics solution to power-coupled-mode equations.

Main Results:

• A complete solution for propagation in randomly bent, circularly symmetric multimode optical fibers was derived.
• The ray-optics solution is equivalent to power-coupled-mode equations in the continuum limit.
• The method effectively incorporates coupling between nonadjacent modes, a limitation in some modal theories.

Conclusions:

• The paraxial-ray-optics approach offers a robust alternative for analyzing light propagation in complex optical fiber systems.
• This ray-optics solution simplifies the analysis by removing common modal theory assumptions.
• The findings enhance the understanding of signal transmission in bent multimode fibers.