Abstract

In recent years, single-mode fiber manufacturing technique has made a remarkable progress in producing low-loss fibers. The mass production of low-loss single-mode fibers stimulated the progress in peripheral techniques surrounding single-mode fiber transmission. The establishment of low-loss light coupling into a single-mode fiber, low-loss connecting, and splicing supports the large-capacity transmission through a single-mode fiber for the longer repeater spacing. In Japan, a 400Mb/s fiber transmission system is now on a field trial conducted since 1980 by NTT[1].