The understanding of frequency-shifting loops’ (FSLs) transient response is fundamental for their implementation in microwave photonic systems. We developed a numerical model, enabling us to describe the specific dynamics of the frequency comb generated in a FSL seeded by a CW laser. The model, based on laser rate equations, predicts the temporal evolution of the power of the individual comb lines during on/off cycles of the injection power, for FSLs operating below the lasing threshold. To prove the validity of the model, we performed experimental measurements of the power of the individual comb lines with time. Numerical simulations based on the model, for different gain media and pumping rates, are in excellent agreement with the experimental results. This paper provides guidance for the concrete implementation of FSLs for microwave photonic applications.

中文翻译：

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移频回路中频率梳的动态行为

对移频环路（FSL）瞬态响应的理解是其在微波光子系统中实现的基础。我们开发了一个数值模型，使我们能够描述由CW激光器播种的FSL中产生的频率梳的特定动态。该模型基于激光速率方程，预测了在低于发射阈值的FSL的情况下，在注入功率的开/关循环中各个梳齿线功率的时间演变。为了证明模型的有效性，我们对各个梳齿线的功率随时间进行了实验测量。基于模型针对不同增益介质和泵浦速率的数值模拟与实验结果非常吻合。