Views:22 Author:Fiberall Technology (Shenzhen) Co., Ltd Publish Time: 2015-06-22 Origin:www.fiber-all.com
Optical fiber is a necessary and most important part of the fiber optic jumper and optical cable. The characteristics of the optical fiber directly affect the performance of the fiber optic patch cord and fiber cable. The characteristic parameters of optical fiber can be divided into three kinds, namely, geometric parameter, optical characteristic parameter and transmission characteristic parameter. Typical parameters include:
1, Attenuation coefficient: attenuation coefficient is one of the most important parameters of multimode fiber (another is bandwidth coefficient). Because it determines the relay distance of multimode optical fiber communication to a great extent. The most important is the attenuation caused by the absorption of impurities. Impurities material in the optical fiber such as hydroxyl ions and transition metal ions (Cu, Fe, Cr) , they are with extremely strong light absorption ability and they are the major factor bring optical fiber attenuation. So in order to obtain the low loss optical fiber, strict chemical purification for raw materials of manufacturing optical fiber such as silica must be done , so that the content of impurities can be reduced to a few PPb.
2, Dispersion and bandwidth: when a light pulse is input from a fiber and passes through a length of optical fiber, the output pulse will be widened or even distorted. This shows that the optical fiber has a broadening effect on the light pulse, that is, the fiber has coloring dispersion. The dispersion of optical fiber is the main cause of the narrowing of the bandwidth of the fiber, and the narrowing of the bandwidth of the fiber will limit the transmission capacity of the fiber.
The dispersion of optical fiber can be divided into three parts, namely, mode dispersion, material dispersion and waveguide dispersion. When light is transmitted in multimode fiber, there are many kinds of transmission modes exists at the same time and each transmission mode is with different transmission speed and phase, so although input optical pulse signal at the same time but the time reach the receiver are different, so pulse broadening happened. For multimode fiber, the dispersion of the material is not dominant because of its serious mode dispersion and its larger value. But for single mode fiber, the mode dispersion is zero, so the material dispersion is the main dispersion. The waveguide dispersion refers to the dispersion caused by the waveguide structures. For multimode fiber, the influence of waveguide dispersion is very small.