网络工程毕业设计外文翻译---什么叫光纤与光纤应用领域

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 exposure 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 of 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, 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 divided 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 somewhere 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 medium 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 injected 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 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 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 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 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 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 reflection 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 propagation 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 The 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 3 is, the diameter of the core points. Small single-mode fiber, multimode fiber thick. Used in fiber optic cable networks are all single-mode fiber, its transmission characteristics, and bandwidth of up to 10GHZ, can be transmitted in an optical fiber 60 PAL-D TV sets. We have a preliminary understanding of the principles of fiber optic transmission of light, then it is also how a variety of text, images, sound transmission from? It turned out that the use of electronic technology, people can be text, images, sound and other information into electronic signals, making them all into the 1 and 0 digit string consisting of, that is what we often call a digital technology . In digital technology, the 1 and 0, said circuit for opening and closing, the use of the optical technology, the bright and dull that they can achieve two states. So, people through Optical (fiber input to the optical signal device) to issue a series of light and dark fiber different light signal, optical fiber receives the other end of the optical signal, then through the specialized equipment to restore it into a digital signal, Finally, from TV, radio, computers and other digital signal will be reduced to text, images, sounds and so on. Optical fiber communication has a tremendous advantage, first, its capacity is amazing, a thin optical fiber can transmit tens of thousands or even hundreds of millions of road calls, you can transmit thousands of television sets, which is unmatched by other transport means The. Second, the optical transmission of light signals, electromagnetic interference from outside it, not afraid of humidity, not afraid of erosion, pollution-free, secure and strong. Optical fiber transmission signal loss is small, only one-tenth of the cable. General coaxial cable, at intervals of 1.5 km is necessary to set up a relay station to compensate for signal attenuation; and fiber optic communications relay station, the distance can exceed 10 kilometers. In addition, the fiber raw material is that we are familiar with the sand (quartz), and more is on the earth and very cheap. Quartz can be produced a few grams a kilometer-long optical fiber. Thus instead of an ordinary metal wire with a fiber can save a lot of valuable non-ferrous metals copper and lead. Very light weight of fiber, 8 fiber made of fiber optic cable, each weighing about 60 kg km only, while the same number of ordinary 4 cable is 4 tons. In fact, far more than the fiber optical communication skills in this area, in many ways, especially in high-tech fields, plenty of fiber not only useless, but new technology is leading the revolution yet. We know that the light can be transmitted in the fiber which is also known to light a variety of information with the basic method. In specific applications of such fiber, some only need one (such as optical communication), while others need a lot of roots (such as transfer beams). In addition, there is a great application of optical fiber, that is, image transmission. Video image transmission means to direct transmission through the fiber, while the middle is no longer as optical communication through the conversion process as a signal. Seen in this light, the transmitted light fiber can be divided into two categories, one with a variety of signal light, one can see the general image of our daily light. Since we can express all kinds of information light, then the fiber can do things way too much. People use to create a wide variety of fiber optic equipment that we collectively are called optical fiber sensors. Fiber optic sensors can not only transmit information, but also access to information. Optical fiber sensors can measure temperature, pressure, vibration, content, position, rotation, deformation, speed, single ring, voltage, electromagnetic fields, etc., are numerous. Although, like fiber optic transmission of light signals without charge in too many things, but its manufacture has to much trouble. Optical fiber transmission, as is usually the number one million by the tens of thousands to the integration of very fine fiber bundle, called the image bundles. It is widely used in endoscopic aspects of the health care industry as we know it to be. 5 英文翻译 什么叫光纤及光纤应用领域 在认识光纤之前，我们先来了解一下光的传播。光是直线传播的，但当光线照射到某一物质上时便会发生折射和反射。我们常会见到玻璃和镜子“反光”就是指光的反射；一半插入水杯中的直棍看起来不再是直的是光的折射造成的假象。其实，我们之所以能够看到各种物体，那都是光的折射和反射造成的（如果没有光，我们什么也看不到）。光可以在真空中传播，也可以在某些物质中传播，这里所说的某些物质，在光学的术语中叫做介质或媒质。玻璃、石英、空气、水、透明塑料等等都可以传播光线，它们都是传播光的介质。不 同的介质密度是不一样的，比如我们知道，水的密度要比空气大很多。表面上看起来差不多的物质（如玻璃和石英），它们的密度也是不一样的。 因此，又分“光密介质”和“光疏介质”。当光线从一种介质射入另一种介质时就会发生折射，好像是光线拐弯儿啦。即使是同一物质，也会因某些环境条件而产生密度不同，如某处的空气热（密度低），某处的空气冷（密度高），光线在穿越冷热空气时也会发生折射（我们熟知的海市蜃楼就是因这种情况而发生的）。照到介质表面上的光叫入射光，经过介质折射的光叫折射光。入射光、折射光和介质的界面（两种介质相接的地方 ）之间存在着一种相互关系，这就是入射角和折射角。两个角度随着入射光线角度的变化而变化。当光线从光密介质射入光疏介质的角度变化到一定程度时，光就不能再射入另一个介质中了，于是就会产生光的全反射现象。 了解了光的传播，我们再来认识光纤。简单的光纤可以就是一根玻璃丝，根据不同要求，它可以做得非常细，一般从几微米到几百微米。通常很多光纤都会在表面加（涂）上一层别的物质，叫包层或涂敷层。这一层物质可以作为光疏媒质起折射作用，有的还可以增强光纤的柔软性使其可以随意弯曲。没有涂敷层的光纤就叫裸纤。裸纤也可以传播光信号（这 时光纤和空气就成了两种不的介质）。根据不同需要，人们在玻璃或石英中可以加入其他化学元素，可以利用多种复杂工艺使细细光纤的内部具有复杂的结构。因此，光纤的品种也是很多的，有的可以同时传送上千种不同波型的光波，有的则只能通过单一波型的光线。光纤的制作过程比较精细，通常叫做拉丝。光纤通信中用到的光缆是由数十到数百根这样的光纤集成的，其中每根光纤都可承担起巨大的通讯量。 6 光所以能在光纤中传输，主要是纤芯和包层的共同作用。根据上面讲到的光折射道理，我们就会明白，光纤的纤芯和它外面的包层肯定是两种密度不同的物质 ，而且纤芯的密度应该大于包层。这样，只要一个光线射入的角度合适，那么这束光线就会在光纤内部不停地进行全反射而传向另一端。 实际应用中的光纤，只要不是过分弯曲，进入光纤的光都会在光纤内来回反射，曲折向前传播，但也会有部分光渗入到包层并在其内传播。光在光纤中传播时也会激发出一定的电磁波模式， 这种模式同光纤的粗细有关，芯径太细难以形成确定的传输模式，芯径太粗则使传输模式增多，使色散严重，固而光纤的纤芯不能太粗也不能太细，一般为传输波长的几倍至几十倍。按照光纤中容许传输的电磁波模式的不同，可以把光纤分为单模光纤和多模光纤。单模光纤指只能传输一种电磁波模式，多模光纤指可以传输多个电磁波模式，实际上单模光纤和多模光纤之分，也就是纤芯的