Vortex Polymer Optical Fiber with 64 Stable OAM States.

Area of Science:

• Optoelectronics
• Materials Science
• Optical Communications

Background:

• Increasing demand for higher bandwidth in optical communication systems.
• Need for low-cost, flexible, and easy-to-handle optical fibers.
• Potential of orbital angular momentum (OAM) modes for mode-division multiplexing.

Purpose of the Study:

• To numerically design an air-core vortex polymer optical fiber capable of supporting a large number of OAM modes.
• To evaluate the performance characteristics of the designed fiber for short-range communication applications.
• To investigate the impact of physical perturbations like bending and ellipticity on mode stability.

Main Methods:

• Numerical design of an air-core vortex polymer optical fiber using cyclic transparent optical polymer (CYTOP).
• Simulation of OAM mode propagation, including effective index difference and propagation losses.
• Analysis of mode coupling spectra under conditions of small bends and slight ellipticity.

Main Results:

• The designed fiber supports 32 OAM modes (64 states with polarization).
• Achieved low propagation losses of approximately 15 × 10^-3 dB/m for all OAM modes.
• Demonstrated very low dispersion for higher-order OAM modes at 1.3 µm wavelength.
• Computed spectra of mutual coupling coefficients, showing lower-charge weights for higher-order OAM modes under perturbation.

Conclusions:

• The proposed CYTOP fiber is a promising candidate for increasing capacity in short-range optical communication systems.
• The fiber exhibits favorable characteristics such as low loss, low dispersion, and mechanical compatibility.
• The study provides insights into the stability of OAM modes in polymer optical fibers under realistic conditions.