Modulation-frequency-controlled change from sub- to superluminal regime in highly doped erbium fibers.
We report a change from sub- to superluminal propagation upon increasing the modulation frequency of an amplitude-modulated 1,550 nm signal when propagating through highly doped erbium fibers pumped at 980 nm. We show that the interplay between the pump absorption and the pump-power broadening of the spectral hole induced by coherent population oscillations may drastically affect the fractional advancement or delay of the signal for the considered fibers.
Melle
Sonia
S
Escuela Universitaria de Optica, Universidad Complutense de Madrid, C/ Arcos de Jalón s/n, 28037 Madrid, Spain. smelle@fis.ucm.es
Calderón
Oscar G
OG
Caro
Cesar E
CE
Cabrera-Granado
E
E
Antón
M A
MA
Carreño
F
F