Non-Zero Dispersion-Shifted Fiber With Trench-Assisted Ring Core for Orbital Angular Momentum Modes

Orbital angular momentum (OAM) based multiplexing technology leverages the spatial information of optical fields, offering potential for expanding optical communication capacity and improving spectral efficiency. In this work, a non-zero dispersion-shifted fiber with trench-assisted ring core is proposed for optimized dispersion management. The impact of various parameters on the chromatic dispersion of fiber is investigated. At 1550 nm, the designed fiber exhibits a minimum dispersion of 2.42 ps/nm/km for the EH<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1,1</sub> mode and a maximum dispersion of 8.71 ps/nm/km for the HE<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14,1</sub> mode. A total of 50 OAM modes adhere to the ITU-T G.655.C standard, with differential mode delays maintained below 4.25 ps/m. Additionally, the fiber features an effective mode area exceeding 982 μm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and a nonlinearity coefficient below 7.23×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> /W/m, ensuring robust support for OAM mode transmission.