Self-induced-transparency solitons in an erbium-doped fiber waveguide

Self-induced transparency (SIT) has been observed in an erbium-doped resonant fiber waveguide. The waveguide had an erbium ion concentration of 8900 ppm, and was cooled to 4.2 K. The pulse source was a 1.53-{μ}m mode-locked Er-doped glass laser with a pulse width of 500 ps. Stable 2{π}, 4{π}, and multiple soliton pulses that broke up were clearly observed.