We present and characterize a narrow-linewidth external-cavity diode laser at 2 μm, and show that it represents a low-cost, high-performance alternative to fiber lasers for research into 2 μm photonic technologies for next-generation gravitational-wave detectors. A linewidth of 20 kHz for a 10 ms integration time was measured without any active stabilization, with frequency noise of ∼ 15 Hz/Hz between 3 kHz and 100 kHz. This performance is suitable for the generation of quantum squeezed light, and we measure intensity noise comparable to that of master oscillators used in current gravitational wave interferometers. The laser wavelength is tunable over a 120 nm range, and both the frequency and intensity can be modulated at up to 10 MHz by modulating the diode current. These features also make it suitable for other emerging applications in the 2 μm wavelength region including gas sensing, optical communications and LIDAR.

中文翻译：

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波长为2μm的可调谐窄线宽激光器，用于重力波探测器的研究。

我们介绍并表征了2μm的窄线宽外腔二极管激光器，并表明它代表了光纤激光器的低成本，高性能替代品，可用于下一代重力波探测器的2μm光子技术的研究。测量了10 ms积分时间内20 kHz的线宽，没有任何有效的稳定作用，频率噪声在3 kHz至100 kHz之间为〜15 Hz / Hz。此性能适合于产生量子压缩光，并且我们测量的强度噪声与当前重力波干涉仪中使用的主振荡器相当。激光波长在120 nm范围内可调，并且可以通过调制二极管电流在高达10 MHz的频率上调制频率和强度。