We present the generation of 12.1 ns frequency chirped pulses from a distributed feedback laser diode via injection current modulation and demonstrate its application to absorption-based methane sensing at 1650.9 nm. The chirp spectral distribution is found to be significantly impacted by the transient dynamics of these short pulses. A simplified, two-part model is used to evaluate the chirp property, suggesting spectral mixing and oscillation. The chirp enables intra-pulse self-calibrated gas sensing by taking the amplitude ratio between the absorption peak and a reference, which is demonstrated for methane concentrations from 0 to 22.6% with a detection limit of 25 ppm. It also provides resistance to power fluctuation from various sources. These short pulses offer high spatial and temporal resolution and can potentially enable reflection-based, highly multiplexed gas sensing systems.

中文翻译：

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用于自校准气体传感的 12ns 频率啁啾脉冲

我们展示了通过注入电流调制从分布式反馈激光二极管生成 12.1 ns 频率啁啾脉冲，并展示其在 1650.9 nm 处基于吸收的甲烷传感中的应用。发现啁啾频谱分布受到这些短脉冲的瞬态动态的显着影响。简化的两部分模型用于评估啁啾特性，表明光谱混合和振荡。啁啾通过获取吸收峰和参考之间的幅度比来实现脉冲内自校准气体传感，这在甲烷浓度从 0 到 22.6% 的情况下得到证明，检测限为 25 ppm。它还可以抵抗来自各种来源的功率波动。这些短脉冲提供高空间和时间分辨率，并有可能实现基于反射的、