提出了一种基于三角晶格的1550 nm波段的光子晶体结构。为了使带隙最大，选取占空比（半径和光子晶体晶格常数的比值）为0.3,采取点缺陷和线缺陷相结合的直接耦合结构。基于Rsoft软件的时域有限差分方法(FDTD)方法仿真计算，对缺陷模、透射谱和时域稳态响应图进行了分析。计算了光开关的插入损耗、消光比和响应时间。结果表明，插入损耗为0.3957 dB，消光比为56.699 dB，响应时间为102.14 ps。该光开关结构的性能较好，可以完全满足现代应用的需求。

A triangular lattice is proposed based on the 1550 nm-band photonic crystal structure. The duty cycle (the ratio of radius and lattice constant of the photonic crystal) is 0.3 in order to achieve the greatest band gap. Based on the combination of point defect and line defect, a direct coupling structure is proposed. With the simulation calculation based on the finite difference time domain (FDTD) Rsoft software, the defect mode, transmission spectra and steady-state time domain response are analyzed. The insertion loss, extinction ratio and response time of the optical switch are calculated. The results show that the insertion loss is 0.3957 dB, the extinction ratio is 56.699 dB and the response time is 102.14 ps. The performance of the optical switch structure is excellent and it can fully meet the requirements of modern applications.