Dual function of nearly zero dispersion flattened and polarization maintaining photonic crystal fiber with broadband of O–U band

We theoretically designed a dual function of nearly zero dispersion flattened and polarization maintaining photonic crystal fiber (DF–PM-PCF) with ultra-broadband. The numeric results show that the DF–PM-PCF performs the nearly zero dispersion values between − 1.00 and − 0.12 ps/km/nm over a bandwidth range of 482 nm (1218–1700 nm). The operation band expands from O band (1260–1360 nm) to U band (1625–1675 nm). In the meanwhile, the birefringence values of the proposed DF–PM-PCF were estimated and show that they are 0.93 × 10⁻³–1.25 × 10⁻³ in the operation band. Confinement losses of some wavelengths in the operation band were calculated and confirmed that they are reasonable. The numeric results indicate that the DF–PM-PCF has confinement losses of 2.75 × 10⁻³–3.39 × 10⁻¹ dB/km in the operation band. Furthermore, the mode properties of the proposed DF–PM-PCF were simulated and confirmed that it works in single mode in the operation band. The device can be well used in a WDM communication system.