Propagation, switching and lasers in special EDFA´s

Erbium-doped fiber amplifiers (EDFAs) have already made a large impact on fiber transmission systems, and they are also beginning to penetrate nonlinear optical applications. We show that EDFAs tailored with particular properties can have novel nonlinear applications in ultrafast, short pulse transmission, switching and lasers. In long distance fiber-optic transmission, low-doped, distributed EDFAs may counteract deleterious effects such as soliton self-frequency shift (SSFS) and Gordon-Haus jitter due to amplified spontaneous emission. Interaction between orthogonally polarized solitons in a rapidly amplifying birefringent EDFA can lead to large frequency shifts that can be used for switching or logic gates. Finally, highly doped, polarization-maintaining EDFAs have been used to generate sub-picosecond pulses from passively modelocked, stable, self-starting lasers. We focus on the required properties for the EDFAs and their features that enable these unique applications