A New Life for Old Fibers

摘要

If the network is already operating on single-mode fiber, upgrades are generally simple. Most single-mode fiber can be upgraded easily by unplugging the current equipment and plugging in newer, faster hardware. However, that's not always true. We like to talk about single-mode fiber as having infinite bandwidth, but longer lengths-especially with older fiber-may not be as good as current manufactured fiber. Plenty of 20-plus-year-old, single-mode fiber made for networks operating at under 1 gigabit per second (Gbps) is still in use. Today's fiber is designed to minimize dispersion for 100 Gbps or more, and the newer fiber is intended for wavelength division multiplexing (WDM), allowing multiple channels of signals to be transmitted simul- taneously over a single fiber pair.