损耗可控条件下掺铒光纤中光速减慢现象的研究

Research on group velocity slowdown in erbium-doped optical fiber under controllable absorption loss

由于相干布居振荡效应,光脉冲通过处于吸收状态的掺铒光纤介质时,将导致群速度传输减慢.由掺铒光纤的吸收特性可知,此时必伴随着强烈的吸收损耗,这势必会给实际的慢光信号测量及光通信领域带来诸多的困难.从铒离子基态粒子速率方程出发,对损耗可控条件下的光速减慢传输进行了数值仿真研究,并加以实验验证.研究表明:抽运光强度越高,信号光损耗系数越小;抽运掺铒光纤长度越长,信号光损耗系数越小.通过优化抽运光强度、掺铒光纤长度等参量,可以实现损耗可控条件下的光脉冲群速度减慢传输.

Group velocity of the optical pulse propagation would be reduced based on coherent population oscillation effect in an absorbing medium. According to the absorption properties of erbium-doped optical fiber, there would appear a sharp absorption loss, which brought more difficulties to the actual measurement of slow light and its application in communications. From the ground rate equation of erbium-ion, the delay of optical pulse was simulated under controllable absorption loss, and experiments were implemented to verify the theoretical results. Moreover, we researched how the different pump power and fiber length effect the signal loss and the optical pulse delay.