Characterization of the dispersion uniformity and nonlinear pulse propagation of photonic crystal fibers

Photonic crystal fibers offer a versatile fiber whose parameters, such as dispersion and nonlinearity, can be designed in great detail. As the position, configuration, and geometry of the complex air hole structure determine the fiber parameters, any associated deviations can impact the overall fiber performance. With a white light interferometry setup for a wavelength range from 930-1070 nm, the longitudinal variation in group velocity dispersion is measured for two different photonic crystal fibers with similar zero dispersion wavelengths and core sizes. The nonlinear pulse propagation of femtosecond pulses in the photonic crystal fibers is characterized and from the optical performance, nonlinear coefficients can be extracted based on numerical simulations. Experimental differences between forward and backward propagation directions are correlated to variations in fiber parameters along the draw distance.