There are a number of special types of single-mode optical fiber which have been chemically or physically altered to give special properties, such as dispersion-shifted fiber and nonzero dispersion-shifted fiber.OverviewIn, a single-mode optical fiber, also known as fundamental- or mono-mode, is an In 1961, while working at American Optical published a comprehensive theoretical description of single mode fibers in the. At the Corn. Unlike, single-mode fiber does not exhibit. This is due to the fiber having such a small cross section that only the first mode is transported. Single-mode fibers are therefore b.