Ring-Core Photonic Quasi-Crystal Fiber With 34 Polarization Multiplexing Modes

We propose a ring-core photonic quasi-crystal fiber (RC-PQCF) featuring a ring-shaped fiber core and two symmetrical SiO 2 stress-applying parts (SAPs). By optimizing the mole percentage of GeO 2 and geometrical parameters of the fiber, the design supports 34 full vector polarization modes (FV-PMs). The effective refractive index difference (\Delta {n_{eff}}) of adjacent FV-PMs is larger than 1.07 \times {10^{ - 4}} at 1550 nm. The confinement loss ({\mathrm{\alpha }}) of FV-PMs is less than {10^{ - 6}}, which is sufficient to confine the light field in the ring-core. Through numerical analysis, broadband performance is investigated subsequently in the 1500-1600 nm. The dispersion ({D_\lambda }) of FV-PMs is less than 138.14{\mathrm{\ ps}} \cdot {\mathrm{n}}{{\mathrm{m}}^{ - 1}} \cdot {\mathrm{k}}{{\mathrm{m}}^{ - 1}} and maintains a flat trend. The mode field area ({A_{eff}}) of FV-PMs is larger compared to single mode fibers and the nonlinear coefficient ({\mathrm{\gamma }}) of FV-PMs is within (6.97 \times {10^{ - 4}}, 1.54 \times {10^{ - 3}}) {{\mathrm{m}}^{ - 1}} \cdot {{\mathrm{W}}^{ - 1}}{\mathrm{\ }} in the 1500-1600 nm. The fiber is a promising design for mode division multiplexing (MDM) that supports the MIMO-free processing and improves the transmission capacity and spectral efficiency.