Tuesday, 31 March 2009

Optical fibre

A classwork passage xd" Topic: Talk about optical fibre (10 mins) Optical fibre is a tube-like devices which can transmit light. It's made by glass and some other material, layer by layer. Since total internal reflection always occur inside the tube, and the tube can be bent into a certain angle, it can transmit light in the curved path(though the light is running in stright line inside the tube). There are various application of optical fibre. The most important use is the usage on telecommunication services. Comparing with the traditional wire, it's much cheaper since the traditional wire uses a lot of copper. Even the material cost is more expensive than the production cost of optical fibre considering the same voume. Optical fibre also transmit information at a higher speed, since the signal medium is light. It gives different signals through different strengths of light, and it's signal is continuous. (The signal of copper wire is transmit by electricity and it's not continuous.) Most of the overseas cable were made by optical fibre now, and major communication network usually uses optical fibre. Centainly there is still is big room for optical fibre to development, following with the globalization, communcations between conutries and countries become more important. This require a high speed and capacity(band width) devices. Optical fibre is the best that we've ever known. In the future, optical fibre will be a major wired devices which can transmit information. It will not be replaced by other devices unless there's a breakthrough in wireless communication techlonogy which is more cheap or able to transmit more information at the same time in a far distance. Optical fibre may be able to transmit more information at the same time by using a more complicated system of signals. In the future, optical fibre may be applicated very frequently in our daily life. And at the moment, there're still some researchs on optics, nano techlonogy, information techlonogy and quantum physics, which will improves optical fibre. This passage was finished by me this morning, within 15 minutes. It's good to create one like this because optical fibre is a broad and intresting topic. =] P.S. This passage talks too much. I don't think that it's all "related to exam". Only the structure and the basic usage is enough although I write this out without any reference... Bold letters are main point that adviced to remember.

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