A REVIEW OF THE FABRICATION AND PROPERTIES OF ERBIUM-DOPED FIBERS FOR OPTICAL AMPLIFIERS

During the last two years, erbium-doped fiber has risen to prominence to become the central component of all optical amplifiers. Applications reported include repeaters, power amplifiers, preamplifiers, and distributed amplifiers. To date, nearly all the fiber used in these devices has been silica based and fabricated by variations on the major telecoms fiber technology. Disadvantages of the silica-based host glass, such as low solubility of the rare-earth ions and narrow-band fluorescence, have been carefully addressed and solutions have been found to overcome these potential drawbacks. Details of the current status of fabrication methods, matching particular fibers for specific applications, together with optimizing the fiber for high efficiency is presented.