Abstract:In this paper, a photonic crystal fiber (PCF) with a dispersion-engineered and high nonlinear coefficient has been designed for supercontinuum generation and frequency comb generation. The proposed PCF has a Si3N4 rod in the core. This rod increases the contrast between the core and the cladding which provides more optical confinement in the core. This confinement reduces the effective mode area of PCF and thus increases the nonlinear coefficient. The effective mod area and the nonlinear coefficient are obtained "0.8" 14〖 μm〗^2 and 25 W-1m-1, respectively. By varying different parameters for dispersion engineering, a suitable dispersion profile for the structure has been obtained so that the proposed PCF has two zero dispersion wavelengths (ZDWs) at 900 nm and 1590 nm. By injecting an input pulse at a wavelength of 1555 nm and a power of 1 kW with a duration of 50 fs to the designed PCF with a length of 4 mm, the output spectrum is broadened in the range of 800 nm to 3500 nm. For frequency comb generation by the four-wave mixing method, phase matching conditions must be provided, and for that, the pumped wavelength must be in the anomalous dispersion regime and near to zero dispersion wavelength. As a result, two continuous wave laser pumping at the wavelengths of 1551 nm and 1558 nm have been injected into the PCF and optical frequency combs with a pulse width of 1 nm and a free spectral range of 7 nm has been obtained.