Octagonal polarization-maintaining supermode fiber for mode division multiplexing system

Abstract

We present a new type of polarization-maintaining supermode fiber which can separate adjacent modes from each other. The proposed polarization-maintaining supermode fiber features an octagonal core composed of multiple high-refractive-index circular holes. By using high refractive index cores and setting the angle subtly between the cores, the fiber proposed can support 22 modes with different polarization states under two parameters in the entire C-band. Through the finite element method simulation, we conducted simulation study to analyze the influence of the angle between the cores and the core diameter on the performance of the optical fiber. In addition, we analyzed effective refractive index difference (Δneff) and effective modal area (Aeff) of the fiber for each characteristic mode. The differential mode delay (DMD) under different cores angle is also calculated. Numerical results present that the minimum Δ neff of the octagonal polarization-maintaining supermode fiber in the entire C-band under the two parameters is greater than 1.1 × 10−4. It was measured to have good tolerance under the condition of unsatisfactory structure. These results indicate that the proposed fiber is superior candidate for improving the optical transmission capacity in the transmission of the mode division multiplexing system.