从理论和实验上研究了利用光注入半导体激光器对高重复速率光脉冲产生的周期振荡和时钟分频现象.结果表明,光注入半导体激光器引起的二倍周期振荡是使注入脉冲重复频率分频的直接原因.通过耦合速率方程,数值模拟了半导体激光器在外光注入时输出光的时间序列和功率谱,并且分析了激光腔内各种周期振荡的特征.研究表明,当注入光使半导体激光器出现稳定的二倍周期振荡,且注入光的重复频率为此振荡频率的二倍时,时钟分频即可产生.实验中,采用重复频率为6.32GHz的光脉冲注入Fabry-Perot激光器,实现了3.16GHz时钟分频信号的输出.所得实验结果与理论分析相符.
The periodic oscillations and clock division in semiconductor laser with external optical injection have been studied theoretically and experimentally. The results indicate that double period oscillation due to semiconductor laser with external optical injection can lead to clock division of the injected optical pulses. We have simulated the time series and power spectrum of output light from semiconductor laser by the coupled rate-equation method, and studied a series of periodic oscillations in laser cavity. When the slave laser was drived into the dynamical period-two state with propriety injection optical power, and modulation frequency of injected optical pulses is twice the oscillation frequency, the clock division of injected optical pulses occurs. Moreover, in experiment, we have demonstrated that the output pulses appear at a repetition rate of 3.16 GHz when optical pulses with 6.32 GHz repetition rate are injected into the Fabry-Perot laser diode. The experimental result is well consistent with theoretical analysis.