In an optical fiber, the material dispersion coefficient, M(λ), characterizes the amount of pulse broadening by material dispersion per unit length of fiber and per unit of spectral width. It is usually expressed in picoseconds per (nanometre·kilometre).
For many optical fiber materials, M(λ) approaches zero at a specific wavelength λ0 between 1.3 and 1.5 μm. At wavelengths shorter than λ0, M(λ) is negative and increases with wavelength; at wavelengths longer than λ0, M(λ) is positive and decreases with wavelength.
Pulse broadening caused by material dispersion in a unit length of optical fiber is given by the product of M(λ) and spectral width (Δλ).
Famous quotes containing the words material and/or dispersion:
“It is not stressful circumstances, as such, that do harm to children. Rather, it is the quality of their interpersonal relationships and their transactions with the wider social and material environment that lead to behavioral, emotional, and physical health problems. If stress matters, it is in terms of how it influences the relationships that are important to the child.”
—Felton Earls (20th century)
“The slogan offers a counterweight to the general dispersion of thought by holding it fast to a single, utterly succinct and unforgettable expression, one which usually inspires men to immediate action. It abolishes reflection: the slogan does not argue, it asserts and commands.”
—Johan Huizinga (1872–1945)