采用时域有限差分法研究两平行光子晶体波导的传输特性及模场分布，利用耦合模理论计算光子晶体波导的耦合系数。计算结果表明，在不同的频率范围内两平行光子晶体波导之间表现出不同的耦合特性：在高频段(0.32~0.44)(ωa/2πc)的范围内两直波导表现出相互的能量交换，实现光耦合，耦合系数随入射波频率增加而减小；而在低频段(0.29~0.32)(ωa/2πc)的范围内，两波导的传输谱图几乎重合。最后，提出一种采用固定波导耦合长度同时实现光分束及光均分器的方案，当耦合长度取34a时，可将频率为0.333 (ωa/2πc)和0.357(ωa/2πc)的两入射波分束传播，同时将低频段中的任意频率波进行能量均分。

The propagating characteristics and mode profiles of two parallel photonic crystal waveguides were studied by using finite-difference time-domain method (FDTD), and the coupling coefficient between the two parallel photonic crystal waveguides was obtained with coupled-mode theory. Numerical results demonstrated that the coupling characteristic between the two parallel photonic crystal waveguides reveals large discrimination within different frequency region. For a high frequency range of (0.32~0.44)(ωa/2πc), they exchange energy each other and optical coupling is realized, the coupling coefficient decreases with the increase of input frequency; while at a low frequency range of (0.29~0.32)(ωa/2πc), the mode profiles of the two waveguides are overlapped. Finally, A solution realizing optical beam splitter and optical power equalizer is proposed using a certain coupling length of 34a, the two incident waves with high frequencies of 0.333(ωa/2πc) and 0.357(ωa/2πc)can be split,meanwhile the wave power with arbitrary frequency at low frequency can be equalized within the two waveguides.