运用传输矩阵法对串联耦合微环谐振腔透射谱进行分析，得出微环谐振腔具有梳状滤波特性。当一个周期脉冲序列通过微环谐振腔时，微环谐振腔的透射梳状谱对脉冲序列的频率进行选择，使得输出脉冲序列的频率增加，经过傅里叶逆变换后的输出脉冲序列周期变小。结果表明，随着频率倍乘数的增加，环半径相同的双环谐振腔相较于单环谐振腔，其输出周期脉冲序列的幅值更统一，脉冲序列频率倍乘(PRRM)效果更好；而串联耦合环半径不同的双环谐振腔能够在减少微环弯曲损耗的同时扩展自由光谱范围(FSR)，从而实现较好效果的PRRM；优化微环谐振腔的耦合系数，其输出的脉冲序列包络呈三角形，实用性大大提高。

Transmission spectrum of series-coupled micro-ring resonator is analysed with transfer matrix method. It shows that the micro-ring resonator has comb filtering properties. When a pulse train goes through the micro-ring resonator, the frequency of input pulse train is choosed by the comb transmission spectrum of the micro- ring resonator, with the output pulse repetition rate multiplied and the period decreased after inverse Fourier transform. The results demonstrate that the amplitude of output pulse train by a double-ring resonator with equal radius is more uniform and the pulse-repetition rate multiplication (PRRM) effect is much better than by a single-ring resonator with the increase of multiplied pulse-repetition rate. Because series-coupled double-ring resonator with different radii can expand the free spectral range (FSR) and reduce the bending loss of the micro-ring resonator, high frequency and low loss of output pulse train can be obtained when it is used to achieve PRRM. The envelope of output pusle train presents triangle by optimizing the coupling coefficient of the micro-ring resonator, which can greatly improve its practicability.