Smajic Jasmin, Hafner Christian, Erni Daniel
Laboratory for Electromagnetic Fields and Microwave Electronics, Swiss Federal Institute of Technology, ETH-Zentrum, CH-8092 Zurich, Switzerland.
J Opt Soc Am A Opt Image Sci Vis. 2004 Nov;21(11):2223-32. doi: 10.1364/josaa.21.002223.
We report on the numerical structural optimization of two-dimensional photonic crystal (PhC) power dividers by using two different classes of optimization algorithms, namely, a modified truncated Newton (TN) gradient search as deterministic local optimization scheme and an evolutionary optimization representing the probabilistic global search strategies. Because of the severe accuracy requirements during optimization, the proper PhC device has been simulated by using the multiple-multipole program that is contained in the MaX-1 software package. With both optimizer classes, we found reliable and promising solutions that provide vanishing power reflection and perfect power balance at any specified frequency within the photonic bandgap. This outcome is astonishing in light of the discrete nature inherent in the underlying PhC structure, especially when the optimizer is allowed to intervene only within a very small volume of the device. Even under such limiting constraints structural optimization is not only feasible but has proven to be highly successful.
我们报告了通过使用两类不同的优化算法，即作为确定性局部优化方案的改进截断牛顿（TN）梯度搜索和代表概率全局搜索策略的进化优化，对二维光子晶体（PhC）功率分配器进行数值结构优化的情况。由于优化过程中有严格的精度要求，合适的PhC器件已通过使用MaX - 1软件包中包含的多极子程序进行了模拟。使用这两类优化器，我们都找到了可靠且有前景的解决方案，这些方案在光子带隙内的任何指定频率下都能实现零功率反射和完美的功率平衡。鉴于底层PhC结构固有的离散性质，这一结果令人惊讶，特别是当优化器仅被允许在器件的非常小的体积内进行干预时。即使在这种限制条件下，结构优化不仅是可行的，而且已被证明是非常成功的。
