Mach-Zehnder电光波导调制器啁啾的研究

Chirp Investigation for Electrooptic Waveguide Modulators with Mach-Zehnder structure

在光纤通信系统中 ,调制器的啁啾参数是衡量调制器性能的重要参数之一。为了深入研究铌酸锂 M- Z结构外调制的机理 ,导出了 Mach- Zehnder结构外调制方式调制器的啁啾参数表达式 ,研究表明该结构调制器频率啁啾不为零 ,而且调制器的直流偏置漂移对啁啾的影响很小。详细讨论了影响啁啾参数的因素 ,分析了直流消光比、外加信号以及直流偏置漂移对器件啁啾参数的影响。分析结果表明 ,利用负啁啾可以改善系统的色散特性。

The chirp parameter of modulators is an important index of performance evaluation in fiber-optic communicalion system. We deduced the expression of the chirp parameter of LiNbO_3 external modulator with Mach-Zehnder structure. It shows that frequency chirp in this structure modulator is not equal to zero and the effect of bias voltage on the chirp parameter can be eliminated. The effect of DC extinction ratio, applied electrical signal and DC bias voltage was analyzed. It shows that negative chirp can improve the dispersion characteristics of system.