简介 |
The present invention relates to a multi-stage optical amplifier for a fiber-optic transmission system, in particular to an amplifier having a multi-stage configuration that allows an optimization of its performance with respect to noise, gain and bandwidth. The multi-stage amplifier of the invention comprises a first amplifying stage (2) including a rare-earth doped optical active fiber (5); a second amplifying stage (3) connected to the first amplifying stage (2), the second amplifying stage (3) including a tellurite-based active fiber (10) doped with a rare earth element; and a third amplifying stage (4) connected with the second amplifying stage (3), the third amplifying stage (4) including a silica-based fiber (14; 30). |