Mode selection and power extraction are the core of single-mode semiconductor lasers, but generally, they restrict each other. A large gain area with high radiation efficiency is necessary for high output power but will induce more competitive modes and increase the threshold gain of the desired mode. Here, we demonstrate a novel laser cavity─an active distributed Bragg reflector (ADBR) and a grating coupler (GC) are monolithically integrated into a laser ridge─enabling independent control of mode selection and power extraction. The ADBR features a reflection peak with an extremely narrow bandwidth that releases the constraint on the cavity length, while the GC provides a controllable high radiation efficiency. The concept is implemented onto terahertz quantum cascade lasers, exhibiting robust single-mode emission with high output power and high operating temperature. Given the universality of the ADBR and GC, our concept can be utilized in different material systems at different wavelengths.

中文翻译：

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太赫兹半导体激光器中模式选择和功率提取的独立控制

模式选择和功率提取是单模半导体激光器的核心，但通常它们相互制约。具有高辐射效率的大增益区域对于高输出功率是必要的，但会引发更多竞争模式并增加所需模式的阈值增益。在这里，我们展示了一种新型激光腔——有源分布式布拉格反射器 (ADBR) 和光栅耦合器 (GC) 单片集成到激光脊中——能够独立控制模式选择和功率提取。ADBR 的反射峰具有极窄的带宽，从而释放了对腔长的限制，而 GC 则提供了可控的高辐射效率。该概念在太赫兹量子级联激光器上实现，表现出强大的单模发射，具有高输出功率和高工作温度。鉴于 ADBR 和 GC 的普遍性，我们的概念可用于不同波长的不同材料系统。