Limitations of Transmission Distances Over Multimode Fiber

Multimode fiber simply refers to the fact that numerous modes or light rays are carried simultaneously through the waveguide. One key characteristic of a multimode fiber is its modal bandwidth. It represents the capacity of a fiber to transmit a certain amount of information over a certain distance and is expressed in MHz/km. An intuitive model is to consider that the signal consists in a number of delayed lines, each of which corresponds to a particular mode. This paper details the limitations in transmission distances suffered by laser-based Gigabit networks operating near a wavelength of 1300nm over multimode fibers. The discussion focuses on the relationship between the actual fiber modal bandwidth and various launch conditions.