Design of ring-sector-assisted PANDA ring-core few mode fiber

Abstract

For the PANDA ring-core polarization-maintaining few-mode fiber (RC-PM-FMF) with the given supported eigenmodes, the minimum effective refractive index difference min(Δn_eff) between the adjacent eigenmodes decreases with the RC size. Consequently, we propose a PANDA RC-PM-FMF assisted by a ring-sector (RS) structure, which can be used to mainly increase the Δn_eff values between the adjacent even and odd eigenmodes with the same polarization. The RS-RC-PM-FMF with an appropriate choice of the parameters can support 10 linearly polarized (LP) eigenmodes, which have min(Δn_eff) values higher than 1.9×10⁻⁴ for the adjacent eigenmodes over the whole C + L band. Furthermore, the fiber is characterized by the low group velocity dispersion (GVD) (−40–20 ps·nm⁻¹·km⁻¹) and effective mode areas (63–104 µm²), while the total losses are within the range of 0.19–0.23 dB/km over the whole band.