Polarization-Maintaining Fiber With Uniform Doping Concentration Supporting 10 Weakly Coupled Modes Designed by Swarm Intelligence

In this study, we propose a polarization-maintaining few-mode fiber (PM-FMF) with a uniform doping concentration, capable of supporting up to 10 weakly coupled modes. The fiber features a simple structure with a perforated core, designed using a particle swarm optimization (PSO) algorithm. The proposed design achieves a minimum effective refractive index difference (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta n_{\text {eff}}$ </tex-math></inline-formula>) of approximately <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.819 \times 10^{-4}$ </tex-math></inline-formula> at 1550 nm, ensuring great mode isolation. Furthermore, the structure demonstrates robust bending resistance, with key parameters optimized to mitigate mode coupling and confinement losses. Error analyses reveal the fiber’s tolerance to fabrication imperfections, including core size, refractive index, and air-hole displacement. This design holds great potential for high-capacity, short-reach optical communication systems, such as data centers. The findings provide valuable insights for designing next-generation optical fibers with low complexity and enhanced performance.