增益开关半导体激光器的三级脉冲整形方案

Three-stage Pulse-shaping scheme for gain-switched semiconductor lasers

摘要:

增益开关半导体激光器产生的光脉冲宽度往往较宽,且具有一定大小的脉冲基座。为了提高增益开关半导体激光器的脉冲质量,提出了三级脉冲整形方案。首先,利用色散补偿光纤(DCF)将增益开关半导体激光器输出的光脉冲宽度从39.381ps压缩到26.681ps,随后利用掺铒光纤放大器(EDFA)和色散位移光纤(DSF)的高阶孤子效应进一步将光脉冲的宽度压缩到20.916ps,最后利用半导体光放大器(SOA)的自相位调制效应区分开脉冲基座与脉冲中心的光谱,并利用光滤波器滤除脉冲基座对应的光谱部分,从而消减脉冲基座,并将脉冲宽度压缩到18.497ps。实验结果表明,该三级脉冲整形方案可以有效地压缩脉冲宽度以及减小脉冲基座,从而提高增益开关半导体激光器输出光脉冲的质量。

Abstract:

In order to obtain high-quality picosecond optical pulses, we proposed a three-stage pulse shaping scheme. A gain-switched semiconductor laser system was built to demonstrate the pulse shaping effect. The system is composed of temperature controlling and driving circuits, a semiconductor laser, a pulse compression element, and a pulse pedestal reduction element. Firstly, a dispersion compensated fiber (DCF) was used to compress optical pulse generated by a gain-switched semiconductor laser by reducing the pulse chirp. Then, the width of the optical pulse was further compressed by using the high-order soliton effect of an erbium-doped fiber amplifier (EDFA) and a dispersion shifted fiber (DSF). Finally, in the saturation operating state of a semiconductor optical amplifier (SOA), its self-phase modulation (SPM) effect was used to widen the spectrum, and an optical filter was used to filter the spectrum corresponding to the pulse pedestal, so as to reduce the pedestal of the optical pulse. The optical pulse width was compressed to 18.497ps. The experiment results show that this three-stage pulse shaping scheme can compress the pulse width and reduce the pulse pedestal effectively.