The band gap property of photonic crystal fiber sample was analyzed by plane wave expansion method

then the position and width of the sample’s band gap was modulated by adjusting hole’s radius and increasing the index difference between inside and outside the hole

at last PBG photonic crystal fiber with wide-gap including S-band

C-band and L-band was obtained.The calculated result shows that when metal oxide was adulterated into SiO2

the band gap was between 1 455 nm and 1 515 nm

while the band gap was between 1 481 nm and 1 632 nm when pouring TiO2 into the air hole

the latter has wider band gap for its higher index difference.The result also shows that the air hole’s radius effect not only the position of band gap

but also the width of band gap

and the position of needed band gap and the range of wavelength by choosing appropriate air hole’s radius.This article also gives intuitionistic relationship of hole’s radius and the band gap’s position and width of photonic crystal fiber.The conclusion is not only helpful for designing photonic crystal fiber in communication band

but also applicable for designing the photonic crystal fiber in the other band.