与光纤有关的几个比较重要的参数（Several important parameters related to optical fiber）.docVIP

与光纤有关的几个比较重要的参数（Several important parameters related to optical fiber） The characteristic parameters of multimode fiber? The attenuation coefficient of a? The attenuation coefficient is one of the most important parameters of multimode fiber (another bandwidth coefficient). Because of the distance relay largely determines the multimode optical fiber communication. The most important is the attenuation caused by the absorption of impurities. In the optical fiber material impurities such as hydroxyl ions and transition metal ions (Cu, Fe, Cr) on light absorption ability is extremely strong, they are a major factor in the production of optical fiber attenuation. So in order to obtain the low loss optical fiber, optical fiber manufacturing must use silica raw materials such as chemical purification is very strict, so that the content of impurities is reduced to a few PPb. ? The dispersion and bandwidth of fiber? Dispersion when a light pulse from the input optical fiber, optical fiber transmission after a certain length, the output end of the optical pulse is wider, even with the obvious distortion. This indicates that the fiber of optical pulse broadening effects, namely fiber dispersion (dispersion based term in optics). The dispersion of fiber is mainly caused by the narrow bandwidth of optical fiber, optical fiber transmission capacity and bandwidth narrowing will limit the fiber. ? The dispersion of fiber can be divided into three parts namely the mode dispersion and material dispersion and waveguide dispersion. ? Delta tau M mode dispersion in multimode fiber optical transmission because it has many kinds of communication modes, and each mode of transmission with transmission speed and different phase, although at the end of the input and the input optical pulse signal to reach the receiver, but the time is different, so produced pulse broadening. ? The multimode fiber, because of its mode of dispersion is serious, and its value is large, so the material dispersio