Measurement of the multiphonon decay rate from the /sup 4/I/sub 11/2/ level in erbium-doped silica, multicomponent silicate, tellurite and fluoride fibers

Summary form only given. With the advent of high powered semiconductor lasers, pump multiplexers, and fiber lasers, the maximum signal output of erbium doped fiber amplifiers (EDFA) is no longer limited by the availability of pump power. One of the key limitations in 980 nm pumped EDFA is the finite lifetime (/spl tau//sub 32/) of the /sup 4/I/sub 11/2/ level of an Er/sup 3+/ ion. This is especially important now in multi-component glasses delivered for gain flattering. While the efficiency of 1480 nm pumped amplifiers is not affected by this lifetime, 980 nm pumped EDFAs, which are necessary to achieve the lowest noise figure, are subject to lifetime constrained efficiency. A direct lifetime measurement of the /sup 4/I/sub 11/2/-/sup 4/I/sub 13/2/ transition in various erbium-doped fibers is reported. Using a time resolved fluorescence technique, the /sup 4/I/sub 11/2/ multiphonon relaxation rates of this transition were determined from the risetime of the /sup 4/I/sub 13/2/ fluorescence.