Mode resolved bend loss in few-mode optical fibers

Area of Science:

• Optical Fiber Communications
• Photonics
• Wave Propagation

Background:

• Few-mode fibers are crucial for advanced optical communication systems.
• Accurate characterization of mode-dependent loss is essential for system performance.
• Existing methods lack the ability to discriminate loss between individual modes.

Purpose of the Study:

• To introduce a novel technique for directly measuring the bend loss of individual modes in few-mode fibers.
• To demonstrate experimental loss discrimination between index-degenerated modes.
• To validate the measurement technique against simulations and established formulas.

Main Methods:

• Utilizing a correlation filter technique with a computer-generated hologram.
• Performing modal decomposition to determine the optical power of each propagating mode.
• Bending few-mode fibers and analyzing the resulting optical power distribution.

Main Results:

• The correlation filter technique successfully measured individual mode bend loss.
• High measurement fidelity was achieved when compared to rigorous loss simulations.
• The method demonstrated the first experimental loss discrimination between index-degenerated modes.
• Results showed good agreement with common loss formulas for step-index fibers.

Conclusions:

• The developed correlation filter technique provides accurate and direct measurement of individual mode bend loss in few-mode fibers.
• This method enables unprecedented experimental discrimination of loss between index-degenerated modes.
• The technique holds significant potential for optimizing few-mode fiber design and performance in optical communication.