Supercell Lattice Method Research Articles

A polymer photonic crystal fiber with high and flattened birefringence

A novel high birefringence polymer photonic crystal fiber (PCF) is proposed in this work. This PCF is composed of a polymer core and a cladding with elliptical air holes and squeezed triangular lattice. The high birefringence is introduced on the combined effect of elliptical air holes and the squeezed lattice. Our numerical results based on the supercell lattice method indicate that the birefringence can reach as high as 0.0018 at 650nm wavelength with a properly designed cladding structure. We also analyze the dependence of the birefringence on structure parameters. And we design a PCF that has high and flattened birefringence.

Birefringence Characteristics of Squeezed Lattice Photonic Crystal Fibers

By using the supercell lattice method, we investigate the influence of the squeezing lattice on the birefringence characteristics of photonic crystal fibers (PCFs). We first define the concept of squeezing ratio and then present a model, with which several types of PCFs are simulated. Simulation results show that the squeezing of PCFs' lattice with the uniform air holes in the cladding can break the multifold symmetry of PCFs and make PCFs highly birefringent. Furthermore, it is reported for the first time to our knowledge that the polarity of PCFs' birefringence can change several times as the air-hole diameter changes.

Mode classification and degeneracy in photonic crystal fibers

Based on supercell lattice method, a novel full vector model is presented to analyze the photonic crystal fibers (PCF). From symmetry analysis of modes of a waveguide, we classify the modes of PCF into nondegenerate or degenerate pairs according to the minimum waveguide sectors and its appropriate boundary conditions. We present the modes of PCF can be labeled by its step index fiber analogs, except the modes with the same symmetry as PCF. The doublet of the degenerate pairs in which both have the same symmetry as PCF will be split into two nondegenerate modes.

Supercell lattice method for photonic crystal fibers

A supercell lattice method, believed to be novel, deduced from the plane-wave expansion method and the localized basis function method, is presented for analyzing photonic crystal fibers (PCFs). The electric field is decomposed by use of Hermite-Gaussian functions, and the dielectric constant of PCFs missing a central air hole is considered as the sum of two virtual different periodic dielectric structures of perfect photonic crystals (PCs). The structures of both virtual PCs are expanded in cosine functions. From the wave equation and the orthonormality of the Hermite-Gaussian functions, the propagation characteristics of the PCFs, such as the mode field distribution, the effective area, and the dispersion property, are obtained. The accuracy of the novel method is demonstrated as we obtain the same results when the dielectric constant is split into two virtual ideal PCs in different ways.