Abstract

For various reasons, such as packaging considerations and reduction of interaction length, it is desirable to use short erbium-doped fibers (EDFs) with a high active-ion concentration. However, the cooperative ion-pair upconversion arising from energy transfer between exited erbium ions in the clusters prevents the efficient operation of erbium-doped fiber amplifiers (EDFAs) with Er³⁺ ion concentrations higher than approximately 1000 ppm.¹ One of the best results for a high-concentration EDF is reported in Ref. 2. The small-signal gain was 7.2 dB for a 36-cm length of fiber, and the gain per unit length was 0.28 dB/cm.

© 1995 Optical Society of America