Broadband dispersion compensating ring-core fiber for orbital angular momentum modes.

Area of Science:

• Optical Fiber Communications
• Photonics
• Materials Science

Background:

• Orbital angular momentum (OAM) fiber is crucial for space-division-multiplexing (SDM) to increase optical network capacity.
• Chromatic dispersion in OAM fibers limits data speed and transmission distance.
• Dispersion compensation fibers are needed to mitigate these limitations.

Purpose of the Study:

• To propose and design a triple ring-core fiber with broadband negative dispersion.
• To investigate its potential for compensating chromatic dispersion in OAM fiber links.
• To analyze the impact of fabrication variations on fiber performance.

Main Methods:

• Theoretical design and simulation of a triple ring-core fiber structure.
• Analysis of optical properties, including dispersion and dispersion slope.
• Investigation of the effects of Ge-doping concentration fluctuations and fabrication errors.
• Evaluation of effective mode area in relation to ring-core widths.

Main Results:

• Achieved highest negative dispersion of -24.47 ps/(nm·km) at 1550 nm.
• Obtained average dispersion slope in the C band ranging from -0.182 ps/(nm^2·km) to 0.065 ps/(nm^2·km) for multi-order dispersion compensation.
• Demonstrated that increased high-index ring widths reduce effective mode area due to enhanced confinement.
• Assessed the impact of Ge-doping concentration fluctuations and fabrication errors on fiber characteristics.

Conclusions:

• The designed triple ring-core fiber exhibits significant broadband negative dispersion.
• It shows potential for compensating positive chromatic dispersion in OAM fiber links.
• The study provides insights into fabrication tolerances for practical implementation.