A novel dual guided modes regions photonic crystal fiber with low crosstalk supporting 56 OAM modes and 4 LP modes

•The designed PCF with two guided modes regions, enabling transmission of OAM modes and LP modes in different regions.•The designed PCF can support 56 OAM modes and 4 LP modes over the S + C + L wavelength band.•In the designed PCF, the low index ring is used to separate the guided modes regions, which is easier to manufacture than the method using air holes.•The proposed PCF has a large manufacturing tolerance through the fault tolerance research. In this paper, a novel photonic crystal fiber (PCF) with dual guided modes regions is proposed, which can support 56 orbital angular momentum (OAM) modes and 4 linear polarization (LP) modes over S + C + L wavelength bands. The introduction of a low refractive index ring enables separation of the guided modes regions and makes the designed PCF easier to fabricate. The characteristics of designed PCF are systematically analyzed by using the finite element method (FEM). The results show that the crosstalk between channels can be ignored and the confinement loss is lower than 5 × 10−8dB/m. Furthermore, dispersion and purity are also analyzed. In summary, the designed PCF has potential applications in the high capacity fiber communication of space division multiplexing (SDM).