Luminescence and related characteristics have been investigated for Er3+hyphen;doped silica glass fibers and for fibers and bulk material of calcium metaphosphate glass. Special interest has been directed toward elucidating relaxation processes leading to 1.5hyphen;mgr;m light emission. Several emissions from higher excited states were investigated and excitedhyphen;state lifetimes were also measured. Approximate radiative and nonradiative transition probabilities have been obtained for the excited levels. These results have confirmed that dominant transitions populating the lowest excited level are stephyphen;byhyphen;step nonradiative relaxations and that only a limited amount of energy is supplied via intermediate radiative transitions. It has also been shown that the 1.5hyphen;mgr;m emission decay time constant elongates with increasing fiber length.
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