Shi Bei, Pinna Sergio, Luo Wei, Zhao Hongwei, Zhu Si, Suran Brunelli Simone T, Lau Kei May, Klamkin Jonathan
Opt Express. 2020 Aug 31;28(18):26823-26835. doi: 10.1364/OE.399188.
Compared to quantum well (QW) lasers, lower dimensional quantum dot (QD) or quantum dash (QDash) devices demonstrate superior performances, owing to their quantized energy levels and increased carrier confinement. Here, we report the systematic comparison of static and dynamic properties of long wavelength (1550 nm) QDash and QW lasers. For the QDash lasers, a higher maximum operating temperature and lower temperature dependence was achieved for long cavities, although the threshold current densities were larger than the QW reference devices. The lasing characteristics for QDashes are significantly improved following the application of a high reflectance (HR) coating on the rear facets. The QDash lasers also exhibit three orders lower dark current, of 45 µA/cm under -1 V reverse bias. Small signal modulation on the 4 × 550 µm Fabry-Perot cavities yields a modulation efficiency of 0.48 GHz/√mA and a maximum 3-dB bandwidth of 7.4 GHz for QDashes, slightly larger than that for the QW devices. Meanwhile, a stronger damping effect was observed for the QDash lasers due to their lower differential gain.
与量子阱（QW）激光器相比，低维量子点（QD）或量子线（QDash）器件由于其量子化能级和增强的载流子限制而表现出卓越的性能。在此，我们报告了长波长（1550 nm）QDash和QW激光器的静态和动态特性的系统比较。对于QDash激光器，长腔实现了更高的最高工作温度和更低的温度依赖性，尽管阈值电流密度大于QW参考器件。在背面施加高反射率（HR）涂层后，QDash的激光特性得到显著改善。QDash激光器在-1 V反向偏压下的暗电流也低三个数量级，为45 µA/cm²。在4×550 µm法布里-珀罗腔上进行小信号调制，QDash的调制效率为0.48 GHz/√mA，最大3 dB带宽为7.4 GHz，略大于QW器件。同时，由于QDash激光器的差分增益较低，观察到更强的阻尼效应。
