Design of Double Cladding Nearly Zero Dispersion Flattened Nonlinear Photonic Crystal Fiber

We present a design of double cladding nearly zero dispersion flattened nonlinear photonic crystal fiber (PCF) with the core consisting of seven missing holes. The dispersion of the designed PCF fluctuates from -0.28 to 0.29ps・km^-1・nm^-1 in the range of 1.35-1.795μm and the dispersion slope is -0.0038ps・km^-1・nm^-2 at 1.55μm. Due to its small air-hole to air-hole pitch in the inner cladding, the effective mode area is 6.48μm² and the effective nonlinearity γ is as high as 13.78W^-1km^-1 at 1.55μm. Two layers of air-hole rings in the outer cladding ensures the loss of the fundamental mode to be 2.9dB/km at 1.55μm and two more air-hole rings can further reduce the fundamental mode's loss to the level of 4.2×10^-3,dB/km.