The temperature-dependent phase noise properties of a monolithic two-section mode-locked semiconductor laser are first investigated. This is performed on a GaSb-based quantum well laser emitting at ∼2 μm. Stable mode locking operation with a fundamental repetition frequency of ∼13.3 GHz is achieved on this laser up to 60 °C. At a fixed temperature, there is no monotonous dependence of integrated jitter on the bias condition. For a given gain current or absorber voltage, there exists a corresponding optimal absorber voltage or gain current, respectively, that minimizes the integrated jitter. More important, the phase noise properties improve obviously at elevated temperatures with the lowest achievable jitter reducing obviously from 3.15 ps at 20 °C to 1.39 ps at 60 °C (100 kHz–1 GHz). We consider that the reason is reduced amplified spontaneous emission noise at high temperatures. This is confirmed by the extracted peak-to-valley ratio of the involved laser modes. We believe that this study provides an important insight into the carrier behaviors and noise performance of mode-locked semiconductor lasers, which is meaningful to their applications especially at high temperatures.

中文翻译：

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发射波长为 2 μm 的两段式 GaSb 锁模激光器的温度相关相位噪声特性

首先研究了单片两节锁模半导体激光器的温度相关相位噪声特性。这是在发射~2μm 的基于 GaSb 的量子阱激光器上进行的。该激光器在高达 60°C 的温度下实现了基本重复频率为~13.3 GHz 的稳定锁模操作。在固定温度下，集成抖动对偏置条件没有单调依赖性。对于给定的增益电流或吸收器电压，分别存在相应的最佳吸收器电压或增益电流，以最小化集成抖动。更重要的是，相位噪声特性在升高的温度下明显改善，可实现的最低抖动从 20 °C 时的 3.15 ps 明显降低到 60 °C (100 kHz–1 GHz) 时的 1.39 ps。我们认为原因是在高温下降低了放大的自发辐射噪声。所涉及的激光模式的提取峰谷比证实了这一点。我们相信，这项研究提供了对锁模半导体激光器的载流子行为和噪声性能的重要见解，这对其应用特别是在高温下的应用具有重要意义。