通过使用正方格介质柱二维光子晶体设计了带有环形谐振器的一种插分滤波器ADF(adddrop filter)结构，该结构具有1个输入端口和2个输出端口，采用时域有限差分法研究了带有1个环形谐振器和2个环形谐振器的ADF结构传输性能。结果表明：该ADF结构在第三通信窗口具有优良的滤波作用，能够根据需要将电磁波信号沿着波导向前后上下4个方向传输，ADF结构还具有可调性开关波长、宽频带、高传输率等特点，在光子晶体集成化、光器件制作等方面具有潜在价值。

This paper presents a photonic crystal add-drop filter (ADF) based on ring resonators. The filter was designed in a 2D square lattice dielectric cylinder photonic-crystal structure which consisted of one input port and two output ports. The transmission properties of the ADF with one photonic crystal ring resonator (PCRR) and two PCRRs were studied by time-domain finite-difference method. The results of investigations show that this structure has high drop efficiency in the third communication window, and the signals dropped by ADF can be propagated along upward, downward, forward and backward directions. This structure has the advantages of tunable switch wavelength, broad band, and high normalized transmission rate. It is applicable in the fields of photonic crystal integration and optical device manufacture.