Light transmission speed of different hybrid pump cascade structures in Er3+ doped fiber

Abstract

In this paper, the general theory of generating fast light and slow light in erbium-doped fiber by hybrid pump cascade structure based on coherent population oscillation effect is given. Through numerical simulation, the effects of pump optical power ratio ([Formula: see text]) on gain, group-induced refractive index [Formula: see text], time delay and fractional delay of pumping structure (1480 and 980[Formula: see text]nm) and pumping structure (980 and 1480[Formula: see text]nm) are studied and analyzed. The effects of pumping structure and pumping direction on time delay, fractional delay and fast/slow light conversion are discussed. In addition, the effects of different pump optical power ratios ([Formula: see text]) on time delay and fractional delay are also discussed. Compared with previous methods such as changing the interaction length and doping ion density, a more suitable optical transmission speed can be obtained by adjusting pump composition, pump direction and pump ratio ([Formula: see text]). This may lead to the optimization of optical communication systems.