Highly Nonlinear Dispersion-Flattened Slotted Spiral Photonic Crystal Fibers

We propose a new type of highly nonlinear spiral photonic crystal fiber (PCF) with flat and low dispersion over a wide wavelength range. The new PCF structure adopts an elliptical slot core. The simulation results show that the nonlinear coefficients in our proposed PCF are (quasi-TE mode) and 226 W^-1 m^-1 (quasi-TM mode) at the wavelength of 1.55 μm and the nonlinear coefficient increases with the wavelength increasing. It is also demonstrated that ultraflattened dispersion of 0.91 ps/(nm·km) (quasi-TE mode) and 1.33 ps/(nm·km) (quasi-TM mode) can be achieved over a 150-nm wavelength range, and two near-zero dispersion slopes of -1.25×10^-3 ps/(nm²·km) (quasi-TE mode) and -4.82×10^-3 ps/(nm²·km) (quasi-TM mode) at 1.55 μm can also be obtained. Owing to its high nonlinear coefficient and flattened dispersion, the proposed slotted spiral PCF will have great potential for all-optical signal processing applications.