There has been one major problem with conventional erbium-doped fiber optic amplifiers. Because of certain characteristics of erbium-doped fiber, dense wavelength division multiplexing (WDM) systems use only 32 nm of usable bandwidth. In the 1550-nm window, 100 nm are available.
With this problem in mind, of Corning, N.Y., developed an experimental silicate-based gain fiber that can increase the usable bandwidth in WDM amplifiers by 50 percent, according to the company. Silicate-based fiber is intrinsically flatter than silica-based fiber, thereby extending the capabilities of conventional band amplifiers past the 32-nm limit. The company says that because it is flatter, the fiber also requires less signal correction.