光子晶体是一种具有光子带隙的新型人工材料,利用其具有控制和限制光子运动的特性可以制成新颖的光学器件。利用硅基二维光子晶体,提出了一种4端口耦合器。采用时域有限差分法作为研究工具,TM模作为研究对象,从理论上分析了这种器件的特性。在不同的耦合长度下研究光在输出端的功率透射率,结果表明选择适当的耦合长度可以使光在器件中呈现不同的状态。进一步研究表明,通过改变器件内部介质柱的半径,可以改变光在输出端的输出功率。从而证实了这种器件不仅具有波长选择性,而且具有潜在的可调节性,这些特性使得这种器件在全光开关的应用上具有潜在的优势。 Photonic crystals, a new type of artificial material with photonic bandgaps, make novel optical devices by virtue of their properties of controlling and limiting photon motion. Using silicon-based two-dimensional photonic crystals, a 4-port coupler is proposed. Using finite-difference time-domain method as a research tool and TM model as the research object, the characteristics of this device are theoretically analyzed. The power transmissivity of the light at the output is studied at different coupling lengths. The results show that light can be made to assume different states in the device by choosing the proper coupling length. Further research shows that the output power of the light at the output can be changed by changing the radius of the dielectric column inside the device. This demonstrates that the device is not only wavelength-selective, but also potentially regulatable, making these devices potentially attractive for all-optical switching applications.