A highly nonlinear photonic quasi-crystal fiber with low confinement loss and flattened dispersion

• A novel photonic quasi-crystal fiber with dual concentric core structure is presented.
• Nonlinear coefficient larger than 33 W−1 km−1, dispersion slope of 8.5 × 10−3 ps/nm2/km at 1550 nm.
• Flattened dispersion of 0 ± 3.4 ps/nm/km, confinement loss of 10−7 dB/m from 1373 to 1627 nm.
• Two zero dispersion wavelengths can be achieved by the proposed design.
• The influence of deviation of each air hole diameter within 3% is discussed to verify the robustness.

We proposed a novel photonic quasi-crystal fiber with near-zero flattened dispersion, highly nonlinear coefficient, and low confinement loss by using the dual concentric core structure. By optimizing the structure parameter, the proposed photonic quasi-crystal fiber can achieve a nonlinear coefficient larger than 33 W−1 km−1 and near-zero flatten dispersion of 0 ± 3.4 ps/nm/km with a near-zero dispersion slope of 8.5 × 10−3 ps/nm2/km at the wavelength of 1550 nm. Near-zero flattened dispersion and low confinement loss in the ultralow order of 10−7 dB/m are simultaneously obtained in the wavelength range from 1373 to 1627 nm. Furthermore, two zero dispersion wavelengths can be achieved in a wide wavelength ranger from 1373 to 1725 nm. From the point of view of practical fabrication, the influence of deviation of each air hole diameter within 3% of imperfections on dispersion, nonlinearity, and is discussed to verify the robustness of our design.