A low loss ultra-narrowband negative-dispersion and large mode field area photonic crystal fiber for dispersion compensation

A hexangular lattice dual-concentric-core photonic crystal fiber is proposed, which is composed of an inner core to be formed by missing a central air-hole, an outer ring core to be produced by reducing the size of the air-holes of the third ring and the double cladding circle air-holes along the direction of fiber length. Based on the full vector finite element method with anisotropic perfectly matched layers, its dispersion, leakage loss and mode field area are numerically investigated. Numerical results indicate that the proposed fiber shows large negative dispersion, strong confinement ability of guide mode, large effective mode area and low leakage loss and low sensitivity to the structure parameters. And the wavelength of high negative dispersion value can be adjusted by artificially choosing the parameters of the proposed PCF, such as Λ, d ₁ and f. The optimal design parameters with Λ=1.2μm, f=0.92, d ₁=0.52μm for proposed PCF are obtained to achieve ultra-narrowband negative dispersion value for dispersion compensation. For the optimal design, the dispersion value reaches as high as -3400 ps·km ^-1 nm ^-1 and the dispersion slope value is between -1000-6000 ps·km ^-1 nm ^-2 over C band (1.53-1.565μm). At wavelength of 1.55μm, the leakage loss is closed to 10 ^-2 dB·m ^-1 and the corresponding area of effective mode is 36μm ².