对矩形谱宽带光抽运下的布里渊慢光延迟特性进行了理论分析。在小信号增益情况下,得到了高斯脉冲延时量、脉冲展宽因子和增益的解析表达式。计算结果表明,当信号光的10 dB带宽小于抽运光带宽的0.357时,解析解和数值解吻合,且信号光脉冲能实现零展宽延迟。单个矩形谱宽带光抽运能达到的最大有效布里渊增益带宽为20 GHz,可以实现半峰全宽约100 ps的高斯光脉冲的零展宽延迟。与高斯谱宽带抽运光相比,矩形谱宽带抽运光可减小脉冲失真。

The delay characteristic of the Brillouin slow light using broadband pump with rectangular spectrum is analyzed. Analytical expressions of the time delay,the pulse-width broadening ratio and the gain of a Gaussian pulse are deduced under small-signal gain approximation. Calculated results show that the analytical solution and the numerical solution agree well and the Gaussian signal pulse can achieve zero-broadening delay,when its 10 dB bandwidth is not greater than 0.357-fold pump bandwidth. The maximum Brillouin gain bandwidth for a broadband pump with single rectangular spectrum is 20 GHz,indicating that zero-broadening delay of the Gaussian pulse with full-width at half maximum of about 100 ps can be achieved. Broadband pump light with rectangular spectrum is more favorable for reducing the pulse distortion than that with Gaussian spectrum.