采用实时功率反馈的半导体激光器幅度调制方法

A magnitude modulation method of laser diode based on real-time power feedback

针对现有半导体激光器(Laser Diode,LD)幅度调制电路具有调制幅度不稳定、调制波形存在非线性失真的缺点,提出采用实时功率反馈的幅度调制方法。通过光电二极管(Photodiode,PD)实时监测LD的输出功率,再根据LD的输出功率自动调整LD工作电流,使其输出功率随调制信号线性变化。最后根据提出的调制方法设计并实现了调制电路,实验结果表明:在温度20~40℃范围内,调制电路的-3 dB带宽达到20 MHz,调制功率的幅度稳定度优于4%,最大非线性误差为0.1%。该调制方法提高了半导体激光器的输出功率稳定性,减少了调制波形的非线性失真,拓宽了半导体激光器的线性工作范围。

The conventional magnitude modulation method of laser diode(LD)has defects,such as unstable modulated magnitude and nonlinear distortion,therefore a new LD magnitude modulation method based on the real-time power feedback was proposed in this paper.Photodiode(PD)was employed to monitor the output power of LD.And the operating current of LD was adjusted automatically according to the monitored output power of LD,by which the output power of LD varied with modulation signal.Finally,a prototype was built and tested.In the range of 20℃to 40℃,The-3 dB bandwidth of prototype was up to 20 MHz,the stability of modulated magnitude was less than 4%and maximum nonlinear error was only0.1%.The results show that the stability of LD output power is improved;the nonlinear distortion of modulated wave is also reduced,with linear working range of semiconductor lasers expanded.