The Effects of Structural Parameters on the Confinement Factor and Single mode Region

In this paper the dependence of single mode region of air-silica microstructures on the structural parameters، the period and diameter of air hole array have been studied theoretically. The calculations have been done for three kinds of microstructures with one، two or three holes missing in the center of fiber by using scalar effective index method. The structures which we call them MOF1، MOF3 and MOF7 respectively have different single mode region. It is shown that MOF1 microstructure has larger single mode region. Optical confinement factor of the MOF1، MOF3 and MOF7 structures have been calculated versus different values of hole diameter، d، and period ، and two values of wavelength =0. 98 & 1. 55 m. Numerical calculations show that MOF7 microstructure has larger confinement factor so this structure is more suitable for optical power transmission. Confinement factor increases with increasing the ratio of d/.