Supercell lattice method for photonic crystal fibers

Enhanced grey wolf algorithm for automatic tuning of an ensemble neural network in predicting PCF optical properties

The structural characteristics of photonic crystal fibers (PCFs) determine their optical properties. This paper introduces an enhanced Grey Wolf Optimization algorithm termed ACD-GWO, which proposes adaptive strategies, chaotic mapping and dimension-based approaches and integrates them into the Grey Wolf Optimization framework. The aim is to achieve efficient automatic adjustment of hyperparameters and architecture for ensemble neural networks. The resulting ensemble neural network demonstrates accurate and rapid prediction of optical properties in PCFs, including effective refractive index, effective mode area, dispersion, and confinement loss, based on the PCF's structural characteristics. Compared to random forest and feedforward neural network models, the ensemble neural network achieves higher accuracy with a mean squared error of 3.78 × 10-6. Additionally, the computational time is significantly reduced, with only 2.27 minutes required for training and 0.08 seconds for prediction, which is much faster than numerical simulation software. This will provide new possibilities for optical device design and performance optimization, driving cutting-edge research and practical applications in the field of optics.

Fabrication and Characteristics of Elliptical-Holes and near Elliptical Core Hexangular Lattice Photonic Crystal Fibers Based on Polymer

The polarization properties of a new structure of high birefringence polarization maintaining photonic crystal fibers were explored, which were consisted of elliptical-holes and near elliptical core triangle lattice of hexangular structure based on polymer. The optical birefringence and the first order polarization mode dispersion were studied based on a full-vector localized basis function method. The numerical results show that the polarization properties are strongly dependent on structural parameters of the PCF. Furthermore, the proposed fiber was fabricated based on MMA monomer polymerization method in situ. So the proposed PCFs may be useful in the field of high birefringence polarization-maintaining optical communication.

Mode degeneration in bent photonic crystal fiber study by using the finite element method

The development of highly dispersive lower and higher order cladding modes and their degeneration with respect to the fundamental core mode in a bent photonic crystal fiber is rigorously studied by use of the full-vectorial finite element method. It is shown that changes in the bending radius can modify the modal properties of large-area photonic crystal fibers, important for a number of potential practical applications.

Meshed index profile method for photonic crystal fibers with arbitrary structures

A meshed index profile method, which is based on the localized function method, is demonstrated for analyzing modal characteristics of photonic crystal fibers with arbitrary air-hole structures. The index profile of PCF, which is expressed as a sum of meshed unit matrix, is substituted to full wave equation. By solving this full wave equation, we obtain the modal characteristics of the PCF such as the mode field distribution, the birefringence and the waveguide dispersion. The accuracy of the proposed meshed index profile method (MIPM) is demonstrated by examining the effective index and the birefringence of the two degenerate fundamental modes in the PCF with a triangular air-hole lattice. The MIPM is not restricted to the PCF structure and will be useful in designing various PCF devices.

Elastic wave propagation in a microstructured acoustic fiber

Elastic wave propagation along the structure of hollow cylinders in a linear isotropic medium is investigated. The multipole method for modeling elastic waves propagation in such structures is formulated and implemented. Using the multipole method, dispersion dependencies of the structures (microstructured fibers) containing 3, 6, and 7 hollow cylinders are calculated. Comparison with wave dispersion properties along one cylinder is made. Also, an approximate physical model based on an equivalent coaxial waveguide and multipole method is proposed. Exploiting this model, wave dispersion of the wave propagating along a structure with 18 hollow cylinders is calculated. Validation of the model is also proposed.