1、 中文 2430 字 本科毕业设计（论文） 英文 翻译 题 目 什么叫光纤与光纤应用领域 学生姓名 专业班级 网络工程 学 号 * 院 （系） 计算机与通信工程学院 指导教师 (职称 ) * （讲师 完成时间 2011 年 6 月 6 日 1 英文原文 What is fiber and fiber optic applications Understanding the optical fiber, we first take a look at the propagation of light. Just a straight line, but when the light exposu
2、re to a substance occurs when the refraction and reflection. We often see the glass and mirrors, reflective refers to the reflection of light； half of the straight stick into the cup is no longer a straight look is an illusion caused by light refraction. In fact, we have been able to see a variety o
3、f objects, that are caused by refraction and reflection of light (if there is no light, we could not see anything.)Propagation of light in a vacuum can also be spread in certain substances, certain substances mentioned here, is called in the optical media or medium terms. Glass, quartz, air, water,
4、clear plastic so the light can be transmitted, they are the medium of light transmission. Different medium density is not the same, such as we know the density of water is much larger than the air. Seemingly similar substances (such as glass and quartz), and their density is not the same. So, is div
5、ided into light denser medium and light sparse media. When the light from one medium will be injected into another medium refraction, like turning the light child friends. Even with the same material, also produced by some of the density of different environmental conditions, such as the air somewhe
6、re hot (low density), somewhere in the cold air (high density), the light passing through hot and cold air can also occur when the refraction ( We are familiar with the mirage is a result of this situation occurs.) Shine the light on the medium surface is called incident, refracted through the mediu
7、m of light is called refraction of light. Incident, reflected light and medium interface (phase two media where) there is a relationship between, this is the angle of incidence and refraction. Two points of view angle as the incident light changes. When the light from the optical denser medium injec
8、ted into the medium angle light thinning to a certain extent, the light can no longer launched into another medium, so will have a total reflection of light. Understanding the propagation of light, let us know fiber. Is a simple glass fiber can be, according to different requirements, it can be made
9、 very thin, usually from a 2 few microns to hundreds of microns. A lot of fiber will usually increase in the surface (coating) layer of another material, called cladding or coating layer. This layer of material can be used as the medium from the refraction of light thinning, and some flexibility can
10、 enhance the optical fiber so that it can be bent. No fiber coating layer is called bare fiber. Bare fiber can also be transmitted optical signal (optical fiber and then the air became two different media.) Depending on the needs of people in glass or quartz other chemical elements can be added, you
11、 can use a variety of complex technology to make thin fibers with a complex internal structure. Therefore, the fiber is a lot of varieties, and some can send thousands of different types of light waves, while others only by a single wave of light. Fiber production process is relatively fine, usually
12、 called the drawing. Optical fiber communications cable used in the root by the tens to hundreds of such integrated optical fiber, each fiber can take a huge traffic. Therefore, in fiber optical transmission, mainly the common core and the cladding effect. Refraction of light according to the above
13、mentioned reason, we will understand that the fiber core, and it is certainly outside of the cladding material of two different densities, and the core density should be larger than the packet layer. Thus, as long as a suitable angle of incoming light, this beam of light will be kept in total reflec
14、tion within the fiber to transmit to the other end. Practical application of optical fiber, as long as not too bent, the light will enter the fiber within the fiber bounces back and forth, twists and turns forward propagation, but also some light into the cladding and in its dissemination. The propa
15、gation of light in fiber will also inspire a certain wave mode, which related with the thickness of the fiber, core diameter is too small to determine the transmission mode is difficult to form, the core diameter is too thick to an increase in transmission mode, the dispersion of a serious, solid Th
16、e fiber core can not be too thick or too thin, generally transmitted several times to several times the wavelength. In accordance with the optical fiber to allow transmission of electromagnetic waves on the mode, can be divided into single-mode optical fiber and multimode fiber. Single-mode fiber that can transmit an electromagnetic wave mode, multimode fiber that can transmit multiple wave modes, in fact, single-mode fiber and multimode optical fiber of the points, that
