有源光纤环形腔的频率滤波特性

本文首先从理论上通过简单的分析得以了有源光纤环形腔的输出谱密度函数公式，该式清楚地表明光纤环形腔的频率滤波特性。从该公式出发，详细分析了环形腔输入光纤宽和环形腔参数对输出光谱谱型和线宽的影响。最后，通过设计不同的环形腔的自由谱宽和不同线宽的激光器作为输出光源，对上述理论分析做了实验验证。理论和实验表明，由于环形腔的强度传递函数是多峰的响应函数，环形腔自由谱宽和输入激光线宽的大小直接影响到环形腔输出光频谱形状，即是单峰输出还是多峰输出，对于不同形状的光谱输出，输出激光的线宽受环形腔的参数影响也各不相同。

Frequency Filtering Characteristics of Active Fiber Ring Resonators

The spectrum function of an active fiber ring resonator was obtained through simple theoretical analysis, which clearly point out the frequency filtering characteristics of active fiber ring resonators. Based on this formula, the effects of the linewidth of input laser and the parameters of an active fiber ring resonator on the output linewidth were discussed. To confirm these theoretical results, some experiments were designed using different input laser and different active fiber ring resonators. All the theoretical and experimental results indicated that the free spectral range (FSR) of an active fiber ring resonator and the linewidth of input laser directly affect the spectral-shape and output linewidth of the ring because of the multi-peaks response of active fiber ring resonators' intensity transmitted function. For a ring with one peak output, the output linewidth is affected together by the input linewidth and the instinct linewidth of the ring, which induced that the output linewidth is narrower than the instinct linewidth. While for the one with multi-peaks output, the output linewidth is close to the instinct linewidth of the ring. Therefore using the optical fiber amplifier to compensate the round-trip loss of an active fiber ring resonator, narrower linewidth laser output can be obtained.