设计了一种二维光子晶体3-Y型4通道分束器,采用时域有限差分方法(FDTD),从理论上计算了该器件4个通道电磁波的透射率。结果表明:当波长选择合适的值,该器件可以实现4个通道同时输出,而且能量近似相等。为了提高电磁波的透射率,可以通过在原来的结构上移去一些介质柱,并改变两个介质柱半径的大小来实现。当两个介质柱半径选择合适的值,可以禁止电磁波在通道1输出,同时让电磁波在通道2低损耗输出。 A 3-Y-type 4-channel beamsplitter was designed for two-dimensional photonic crystal. The transmission of four channels of electromagnetic wave was calculated theoretically by FDTD method. The results show that when the wavelength is chosen properly, the device can output 4 channels at the same time with similar energy. In order to improve the electromagnetic wave transmissivity, it can be realized by removing some dielectric columns on the original structure and changing the radius of the two dielectric columns. When the radius of the two media columns chooses a suitable value, the electromagnetic wave can be prohibited from being output on channel 1 and the electromagnetic wave can be output on channel 2 with low loss.