Abstract

Stimulated by the rapid development of Er-doped fiber amplifiers, rare-earth doped glass films are drawing increasing attention for amplifiers and lasers, suitable for integrated optics. Thin-film waveguide devices, in general, require high rare-earth concentration (two or three orders of magnitude higher than that of fiber amplifiers) in order to obtain a certain amount of optical gain in a relatively short length, i.e., in centimeters as opposed to meters for Er-doped fibers. In highly Er-doped waveguides, however, a series of undesirable effects have been observed, such as reduction in fluorescence decay lifetime, multiexponential decay in fluorescence, and fluorescence emission at visible wavelengths for infrared pump. These effects usually degrade amplifier performance by reducing efficiency and gain.

© 1995 IEEE