从半导体激光直接调制理论出发，对直接调制过程中影响半导体激光器高频调制性能的因素进行了研究；运用PSpice建立半导体激光器等效电路模型，仿真研究了电学寄生参数对半导体激光器调制特性的影响且提出了相应的提高其调制性能的方法。在研究半导体激光器调制特性的基础上，设计了一种半导体激光直接调制系统。运用OrCAD/PSpice对直接调制驱动系统进行仿真。研制的半导体激光调制系统实现了频率为1 MHz、平均功率为1.1 W的调制激光输出。

In this paper, we studied the factors that affect the high frequency modulation performance of semiconductor laser in the process of direct modulation. The equivalent circuit model of LD is derived from the rate equation of semiconductor laser, which was established by using PSpice. We analyzed the effects of the parasitic parameters, the DC bias and the current modulation intensity on modulation characteristics of the laser, and put forward the corresponding methods to improve the performance of modulation. We designed a direct modulation system of semiconductor laser and simulated the system by OrCAD/PSpice. This system can output modulation semiconductor laser with frequency of 1 MHz and average power of 1.1 W.