Characteristics comparison of the ZDSFs based on the triangular graded index and step index single-mode optical fibers

In this paper, the zero-dispersion shifted single-mode optical fibers based on the triangular graded index and step index profiles are successfully designed by applying the method outlined by Oskoui et al. (Journal of Applied Optics, 46 (2007) 6330) and the optimal values for the structural parameters are evaluated. Simulation results indicate that in order to shift the zero-dispersion wavelength near to 1.55 μm, the larger core radius is required in the triangular graded index optical fiber compared to the step index one which is useful from fiber fabrication view points. Also, the dispersion and dispersion slope values in the triangular graded index structure are smaller than ones in the step index type and this fact make a great enlargement in the dispersion and higher order dispersion lengths. However, the nonlinear behavior of the step index ZDSF is superior due to larger effective area, but owing to smaller higher order dispersion length, the transmission distance will be restricted with dispersion slope influence instead of nonlinear effects. Meanwhile, the thermal coefficients of the designed graded index are lower than the structure based on the step index and as a result this kind of fiber has better sustainable behavior against temperature variances.