Article comprising a hybrid multistage optical fiber amplifier

摘要

Multistage Er-doped fiber amplifiers (EDFAs) (60) are disclosed. They comprise a first stage (63) that comprises Er and Al, and further comprise a second stage (67) that comprises Er and a further rare earth element, exemplary Yb. Such multistage EDFAs can have advantageous characteristics e.g., a relatively wide flat gain region (e.g. 1544-1562 nm), and relatively high output power, without significant degradation of the noise figure. Exemplary, the amplifiers are used in WDM systems and in analog CATV systems (110). <IMAGE>