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A holey fiber having a core with an elliptical-hole lattice structure, which is referred to as an elliptical-hole core circular-hole holey fiber (EC-CHF), can be easily designed as a single-polarization fiber by using the fundamental space-filling modes of the core and cladding lattices. However, because the guided mode in an EC-CHF has a polarization that arises from the large geometric anisotropy of the core lattice, the influence of the bending direction on the bending loss is a crucial issue for the practical implementation of EC-CHFs. Here, the bending losses of an EC-CHF bent in arbitrary angular orientations with respect to the core cross section are calculated numerically using the equivalent anisotropic step-index circular fiber model for a real EC-CHF, and the influence of the bending direction of the fiber on the bending loss is discussed. OCIS codes: 060.2310, 060.2400, 060.2420.

Modal dispersion properties of a fabricated plastic optical fiber are numerically calculated through a finite-element method. The modal index, group delay, impulse response, and output pulse shape are compared with those for the power-law profile plastic optical fiber; the influence of index profile deviations from the power-law profile is described. It is shown that index profile fluctuations in the actual index profile strongly affect the group delays, even though they are relatively small. On the other hand, they have little effect on the modal indices. OCIS codes: 060.2310, 060.2400.

Plastic optical fibers that are a typical large-core multimode optical fiber support a great number of modes compared with conventional silica-glass multimode optical fibers. So far the WKB method has been used for most of the modal analyses of these fibers because of a great number of guided modes. We describe the accurate eigenmodal analysis of large-core multimode optical fibers with the finite-element method (FEM) and compute the propagation constants of all LP modes. In addition, the FEM has a strong advantage for arbitrary core profiles whereas the WKB method is not suitable for nonmonotonic profiles. To demonstrate the advantage, we apply the FEM to the fiber having sinusoidal fluctuations. OCIS codes: 060.2310, 060.2400.

Simulation of the behavior of optical soliton in optical fibers is possible by solving for the nonlinear Schrodinger equations. A comparison between the propagating-beam method (PBM) and split-step finite-element (SSF) method of solving for Schrodinger equations showed that SSF based on the finite-element method is as efficient in deriving the number of descretizing points and step size along the propagating axis as PBM.

Research has been conducted on eae-positive Escherichia coli. The authors have investigated the prevalence of eae-positive E. coli in cattle feces, and have genetically characterized the discovered intimin types and the virulence genes from the isolated strains.

We proposed a novel polarization splitter based on single-polarized elliptical-hole core circular-hole holey fibers (EC-CHFs). We employed the full-vector finite element beam propagation method to demonstrate the polarization splitter which is designed by the large hole EC-CHFs (air filling fraction in core is 36.73%) and small hole EC-CHFs (air filling fraction in core is 4.08%) can completely split an arbitrarily polarized light beam into two orthogonal polarization states without any crosstalk. In addition, we also calculated the tolerance and wavelength dependence of this kind of polarization splitter. [ABSTRACT FROM PUBLISHER]