This work investigates the dynamic and nonlinear properties of quantum dot (QD) lasers directly grown on silicon with a view to isolator-free applications. Among them, the chirp parameter, also named the αH factor, is featured through a thermally insensitive method analyzing the residual side-mode dynamics under optical injection locking. The αH at threshold is found as low as 0.32. Then, the nonlinear gain is investigated from the gain compression factor viewpoint. The latter is found higher for epitaxial QD lasers on silicon than that in heterogeneously integrated quantum well (QW) devices on silicon. Despite that, the power dependence of the αH does not lead to a large increase of the chirp coefficient above the laser’s threshold at higher bias. This effect is confirmed from an analytical model and attributed to the strong lasing emission of the ground-state transition, which transforms into a critical feedback level as high as −6.5 dB, which is ∼19 dB higher than a comparable QW laser. Finally, the intensity noise analysis confirms that QD lasers are overdamped oscillators with damping frequencies as large as 33 GHz. Altogether, these features contribute to fundamentally enhancing the reflection insensitivity of the epitaxial QD lasers. This last feature is unveiled by the 10 Gbit/s error-free high-speed transmission experiments. Overall, we believe that this work is of paramount importance for future isolator-free photonics technologies and cost-efficient high-speed transmission systems.

中文翻译：

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用于无隔离集成的硅上外延量子点激光器的动态和非线性特性

这项工作研究了直接在硅上生长的量子点 (QD) 激光器的动态和非线性特性，以实现无隔离器的应用。其中，啁啾参数，也称为 αH 因子，是通过一种热不敏感方法分析光学注入锁定下的残余边模动力学来表征的。发现阈值处的 αH 低至 0.32。然后，从增益压缩因子的角度研究非线性增益。后者在硅上的外延 QD 激光器中比在硅上的异质集成量子阱 (QW) 器件中更高。尽管如此，αH 的功率依赖性不会导致线性调频系数在较高偏压下大幅增加超过激光阈值。分析模型证实了这种效应，并归因于基态跃迁的强激光发射，其转变为高达 -6.5 dB 的临界反馈水平，比类似的 QW 激光器高约 19 dB。最后，强度噪声分析证实 QD 激光器是阻尼频率高达 33 GHz 的过阻尼振荡器。总之，这些特征有助于从根本上提高外延 QD 激光器的反射不敏感性。最后一项功能由 10 Gbit/s 无差错高速传输实验揭晓。总的来说，我们相信这项工作对于未来的无隔离光子技术和具有成本效益的高速传输系统至关重要。这比可比较的 QW 激光器高约 19 dB。最后，强度噪声分析证实 QD 激光器是阻尼频率高达 33 GHz 的过阻尼振荡器。总之，这些特征有助于从根本上提高外延 QD 激光器的反射不敏感性。最后一项功能由 10 Gbit/s 无差错高速传输实验揭晓。总的来说，我们相信这项工作对于未来的无隔离光子技术和具有成本效益的高速传输系统至关重要。这比可比较的 QW 激光器高约 19 dB。最后，强度噪声分析证实 QD 激光器是阻尼频率高达 33 GHz 的过阻尼振荡器。总之，这些特征有助于从根本上提高外延 QD 激光器的反射不敏感性。最后一项功能由 10 Gbit/s 无差错高速传输实验揭晓。总的来说，我们相信这项工作对于未来的无隔离光子技术和具有成本效益的高速传输系统至关重要。这些特性有助于从根本上提高外延 QD 激光器的反射不敏感性。最后一项功能由 10 Gbit/s 无差错高速传输实验揭晓。总的来说，我们相信这项工作对于未来的无隔离光子技术和具有成本效益的高速传输系统至关重要。这些特性有助于从根本上提高外延 QD 激光器的反射不敏感性。最后一项功能由 10 Gbit/s 无差错高速传输实验揭晓。总的来说，我们相信这项工作对于未来的无隔离光子技术和具有成本效益的高速传输系统至关重要。