提出了基于二维光子晶体的具有偏振选择功能的横电(TE)和横磁(TM)波三等分功率分配器, 功分器结构构建于正方晶格的十字形光子晶体波导中。利用有限元法计算结构的性质, 利用Nelder-Mead算法进行了参数优化。结果表明, 在输入通道引入不同的偏振选择缺陷, 可使功分器具有偏振选择功能。对于TE功分器, TE波能够进入并在其中传输, TM波则不能进入; 对于TM功分器, 情况则刚好相反。在波导的十字交叉区域引入功率控制缺陷, 可使各输出端功率相等。合理选择参数, TE和TM功分器的总传输效率分别可达99.48%和95.53%。波长扫描发现两种功分器都可工作在相对较大的波长范围内。

We propose polarization selective three-equal-power splitters for transverse-electric (TE) and transverse-magnetic (TM) waves based on two-dimensional photonic crystals. The structures are constructed by square-lattice cross-shaped photonic crystal waveguides. The finite element method and the Nelder-Mead optimization method are used to calculate the properties of the structures and obtain the optimized parameters, respectively. The results show that the power splitters are polarization selective when different polarization-selective defects are set in the input channels. For the TE power splitter, TE waves can enter the splitter and transmit in it, while TM waves cannot enter it; for the TM power splitter, the situation is just reversed. In addition, the power splitters can obtain the identical power output at various ports when power-control defects are set at the cross junction of the waveguides. With optimized parameters, the total transmission efficiency of the TE and TM power splitters can be up to 99.48% and 95.53%, respectively. Moreover, it is found by wavelength scanning of the structures that these two splitters can work in a relatively wide wavelength range while keeping good performance.