Abstract

Fiber optic communications have been aided considerably by the coincidence at roughly 1550 nm of the minimum in the loss curve of Ge-doped silica and the peak of the emission spectrum of the ⁴I_13/2 → ⁴I_15/2 electronic transition of the trivalent erbium ion, Er³⁺. It has enabled large numbers of wavelength-multiplexed channels to be transmitted over considerable distances, boosted along the way by comparatively inexpensive erbium-doped fiber amplifiers (EDFAs) with excellent signal-to-noise characteristics. The pre-eminent fiber host in practical applications is alumina- and germania-doped silica (Al/Si), which offers a potent combination of low loss, high power-conversion efficiency, compatibility with 980 nm pump, mature fabrication technology, high fiber strength and reliability, and compatibility with a preferred fiber joining technology, arc-fusion splice.

© 2001 Optical Society of America