Reduced linewidth enhancement factor due to excited state transition of quantum dot lasers.
Reduced linewidth enhancement factor due to excited state transition of quantum dot lasers.
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DOI：
10.1364/ol.37.001298
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发表时间：
2012-04
期刊：
影响因子：
3.6
通讯作者：
P. Xu;H. Ji;J. Xiao;Y. Gu;Yongzhen Huang;Tao Yang
中科院分区：
文献类型：
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作者：
P. Xu;H. Ji;J. Xiao;Y. Gu;Yongzhen Huang;Tao Yang
通过测量 InAs/GaAs 量子点 (QD) 激光器结构的光学增益光谱，比较了基态 (GS) 和激发态 (ES) 跃迁引起的载流子引起的折射率变化和线宽增强因子 α。结果表明，与 GS 转变产生的值相比，ES 转变表现出降低的 α 因子。该结果可以通过以下原因来解释：ES跃迁导致的α因子从润湿层和InGaAs应变减少层的组合状态中的非谐振载流子的增加比GS跃迁导致的α因子增加更小，因为载流子从润湿层和InGaAs应变减少层的组合状态到ES的弛豫时间比到GS的弛豫时间短。这里报告的结果显示了除了更高的调制速度之外，使用 ES QD 激光器进行光通信的另一个优势。
The carrier induced refractive index change and linewidth enhancement factor α due to ground-state (GS) and excited-state (ES) transitions have been compared by measuring the optical gain spectra from an InAs/GaAs quantum dot (QD) laser structure. It is shown that the ES transition exhibits a reduced α-factor compared to the value due to the GS transition. This result can be explained by the α-factor due to the ES transition having a smaller increase from the non-resonant carriers in the combined state of the wetting layer and InGaAs strain reducing layer than the α-factor increase due to the GS transition, since the relaxation time for carriers from the combined state of the wetting layer and InGaAs strain reducing layer to the ES is shorter than to the GS. The result reported here shows another advantage of using ES QD lasers for optical communication, in addition to their higher modulation speed.