Modified Trust Region Algorithm for Dispersion Optimization of Photonic Crystal Fibers

In this paper, a modified derivative-free surrogate-based trust region optimization algorithm is proposed for optimizing the dispersion properties of photonic crystal fibers (PCFs) for the first time to the best of our knowledge. The modal analysis of the PCF is made using the full vectorial finite difference method with perfect matched layer boundary condition. The numerical results are compared with another trust region algorithm and other metaheuristic techniques to show the strength of the reported technique. Further, the modified algorithm is also used to achieve a nearly ultra-flattened zero dispersion over a wide range of wavelengths from 1.45 μm to 1.6 μm using an index guiding soft glass PCF selectively infiltrated with a nematic liquid crystal. In order to show the strength of the reported algorithm, a highly negative flat dispersion compensation PCF is also designed over wavelength range from 1.4 μm to 1.6 μm. Such a design has a negative dispersion of -155 ± 0.5 ps/Km·nm over the studied wavelength range. The trust region algorithms show a strong potential as an efficient tool for the design and optimization of different photonic devices. Further, these algorithms can be used as powerful techniques for solving the inverse problems.