１ 前言t所有的迹象表明数据的传输量将继续增加。一个特别重要的趋势是局域网（ＬＡＮ）传输速度的增加；下一代Ｅｔｈｅｒ网络的速度为１０Ｇｂｉｔ／ｓ，与目前的主干传输系统的速度相同。我们现在正生活在一个零距离的世界，在这世界里与地球上任何人的联系可借助于光通信? 1 Preface tAll the signs indicate that the amount of data transferred will continue to increase. A particularly significant trend is the increase in local area network (LAN) transfer speeds; the next generation of Ether networks is at 10 Gbit / s, the same speed as the current backbone transport system. We are now living in a distant world in which the connection with anyone on Earth can be achieved by means of optical communication?