In this paper, we investigate for the first time the dispersion properties of photonic crystal fibers (PCFs) with a continuously-decreasing zero-dispersion wavelength (ZDW) along their length, via solving the eigen-value equation of the guided mode using the finite-difference frequency domain (FDFD) method. Since the structural parameters such as air-hole diameter d and the pitch Λ of the microstructured cladding change along the tapered PCFs, dispersion properties change with the fiber length as well. Therefore, it is important to know the exact behaviour of such characteristics along z which is necessary for nonlinear optics applications. We simulate the z-dependency of the ZDW along the tapered PCFs for various d and Λ and propose useful analytical relations for describing such characteristics. The results of this paper which are in a very good agreement with the available experimental ones, are important for simulating pulse propagation as well as investigating nonlinear effects such as supercontinuum generation and parametric amplification in tapered PCFs.

واژه‌های کلیدی: Photonic crystal fiber، finite-difference frequency domain، tapered fiber، dispersion.

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