Wavelength Dependent α-Profile Model of Multimode Fiber-Optic Channel

A model for the α-profile multimode GI fiber-optic channel including the wavelength dependence of the fiber around the optimum value of α is developed. Losses due to propagation (Ultra lowloss fibers) and modal mixing (more significandy affects the BER probability) are neglected in this paper. The parameters influencing the total dispersion in the GI fiber such as the source wavelength, wavelength dependent refractive index, the group delay variation with the propagating mode order and the source spectral width are used in accurately modelling the transfer function of the multimode fiber. From the numerical analysis carried out for the three distinct wavelengths of 850 nm, 1300 tun and 1550 nm, it was found that very small changes in α lead to a considerable difference in the bandwidth of the fiber and the maximum bandwidth of 0.59 GHz is achieved for distinct values of α being 2.03525, 1.86453 and 1.78205 respectively. For the above values derived the optimum value of α show a considerable decrease as the operating wavelength is increased from 850 nm to 1550 nm in the far Infra-Red (IR) range.