In order to analyze the flat dispersion properties of microstructure fibers

a microstructure fiber with a circular arrangement is designed

the cladding of which consists of periodically distributed air holes.Its dispersion property is numerically simulated by using the finite element numerical analysis method and the dependence of dispersion on the size of the circular holes of the core and wavelength is investigated.The results show that the spaces between the inner and outer air holes and diameter both affect the dispersion curve

but the space between the big holes in the inner cladding and the diameter of the first circle of small air holes play a decisive role in the curve trend.When the diameter of the inner air holes is 3.1 μm and those of the others 10 μm

and the space from center to center of the inner air holes is 5 μm and those of the others 4 μm

the dispersion is 19.5 ps/（nm·km） at the wavelength of 1.3 μm and 26.5 ps/（nm·km） at the wavelength of 1.6 μm

and the dispersion varies in the range of 7 ps/（nm·km） in the wavelength range of 1.3-1.6 μm.