In the early 1950s the researchers who produced the first clad glass optical fibers were not thinking of using them for communications. (1) H____, fiber optics was already a well-established commercial technology when the famous paper by Kao and Hockham, (2)____(claim) the use of low-loss optical fibers for communication, appeared in 1966.　　The first low-loss silica fiber was described in (3)____ which appeared in October of 1970. The date of this publication is sometimes (4)____(cite) as the beginning of the era of fiber communication. Although this development did receive (5)____(consider) attention in the research community at the time, it was far from inevitable that a major industry would evolve.　　The technological barriers appeared formidable because there were serious doubts as to (6) wh_____ these fiber components could ever be produced economically enough, but the market potential was very significant. (7)____(consequence), research and development activity expanded rapidly, and a number of important issues were (8) re_____ during the early 1970s. During the middle and late 1970s，the rate of progress towards marketable products accelerated as the emphasis (9)____(shift) from research to engineering. Fibers with losses (10) app____ the Rayleigh limit of 2 dB/km at a wavelength of 0.8μm were produced.　　By 1980 improvement in component performance, cost, and reliability led to major commitments on the part of telephone companies.

发布日期：2021-09-16

题王网让考试变得更简单

扫码关注题王，更多免费功能准备上线！