专业英语-optical概要.pptVIP

However, a general understanding of the basic nature and properties of light is assumed. 但是，全面的对光的本质和特性的理解仍然在继续。 （d）immunity to interference and cross-talk. Optical fibers form a dielectric wave-guide and are therefore free from electromagnetic interference (EMI), radio frequency interference (RFI) or switching transients giving electromagnetic pulse (EMP). (d)抗干扰和无串话。光纤构成了一个介质波导，因此免除了电磁干扰，射电干扰和瞬态开关带来的电磁脉冲。 Hence the operation of an optical fiber communication system is unaffected by transmission through an electrically noisy environment and fiber cable requires no shielding from EMI. 因此，一个光纤通信系统的操作不会被传输空间中的电子噪声影响而不需要做电磁屏蔽处理。 The fiber cable is also not susceptible to lightning strikes if used overhead rather than underground. 既便是用于高处而不是地下，光纤也不易受到雷电的影响。 Moreover, it is fairly easy to ensure that there is no optical interference between fibers and hence, unlike communication using electrical conductors, cross-talk is negligible, even when many fibers are cabled together. 此外，确保在光纤之间没有光学干扰是相当容易的，因此，即使很多光纤在一起时，也不像用电缆连接那样串话需要被考虑。 （e）Signal security. The light from optical fibers does not radiate significantly and therefore they provide a high degree of signal security. 信息的安全性。光在光纤中不会产生明显的辐射，因此它提供了很高的信息的安全性。 Unlike the situation with copper cables, a transmitted optical signal cannot be obtained from a fiber in a noninvasive manner (i.e. without drawing optical power from the fiber). 不像用铜电缆的情形，一个传输的光信号不能以非介入的方式从光纤中获得。（也就是不能从光纤中获得光功率）。 Therefore, in theory, any attempt to acquire a message signal transmitted optical signal may be detected. 因此，理论上，任何试图获取被传输的光信号中的信息都会被发现。 This feature is obviously attractive for military, banking and general data transmission (i.e. computer network) applications 这个特点对于军事，银行和通用的数据传输（也就是计算机网络）的应用来说都十分有吸引力。 （f）low transmission loss. The development of optical fibers over the last twenty years has resulted in the production of optical fiber which exhibit very low attenuation or transmission loss in comparison with the best copper conductor