Simulation Study of Waveguide and Chromatic Dispersion of a Single Mode Step Index Optical Fiber

Abstract

An optical fiber is a superior medium of transmitting a signal from one end to the other end. It has the characteristics of longdistance transmission and large capacity to accommodate signal, but the dispersion in the fiber is one of the most important
reasons for signal degradation. Dispersion depends on various parameters such as the operating wavelength, core radius, relative
refractive index difference, source spectral width and length of the fiber link. We perform a simulation study of the waveguide and
chromatic dispersion in a single mode step index optical fiber. The study has been done by using the simulation software “Understanding Fiber Optics on a PC”. It has been found that pulse broadening due to waveguide dispersion decrease with
increasing relative refractive index difference between core and cladding for 1310 nm of operating wavelength, 4.5 μm of core
radius, 2 nm of spectral width and 50 ps of the input pulse width. It is observed that waveguide dispersion is negative in the single
mode fiber region. On the other hand, chromatic dispersion becomes zero for the operating wavelength of 1310 nm, 4.5 μm of
core radius, 2 nm of the spectral width, 50 ps of input pulse width and 0.20% of relative refractive index difference. For this zero chromatic dispersion, the optical pulse remains unchanged through a large distance of about 100 km of fiber length. This result
will be an important consideration for designing of the good optical fiber.