用光传送数据，是本世纪下半叶的重大技术进展之一。光纤是这种传输的最雄辩的最简单介质之一。尽管数据通信传统方法用的铜和玻璃非常适合特殊应明，但它们也各有自身的固有限制。铜由于很易受干扰的影响，不适合高速数据传输，玻璃的细直径和易碎性使它安装费用很高。填空铜? Transmitting data with light is one of the major technological advances in the second half of this century. Optical fiber is one of the most eloquent and simplest mediums for this transmission. Although copper and glass used in traditional data communications methods are well-suited for special applications, they also have their own inherent limitations. Copper is not suitable for high-speed data transmission due to its susceptibility to interference. The thin diameter and friability of glass make it costly to install. Fill in the blank copper?