Influence of the angle-dependence of mode coupling on optical power distribution in step-index plastic optical fibers

Determination of the power distribution in step index plastic optical fibers by the power flow equation has been reported in the literature both with and without the simplifying assumption of constant coupling that is independent of the angle of light propagation. The need for this assumption is evaluated in this paper. Results with the angle-dependent coupling coefficient are compared to those derived under the simplifying assumption of constant coupling. Benchmarked to values measured experimentally, this comparison covered the coupling lengths L_c (denoting where the equilibrium mode distribution is achieved in the fiber) and lengths z_s (for achieving the steady-state distribution). Results differ slightly but only for longer fiber lengths, thus largely vindicating the simplifying assumption of constant coupling.     

On Equitorsion Holomorphically Projective Mappings of Generalized Kählerian Spaces

In this paper we investigate holomorphically projective mappings of generalized Kählerian spaces. In the case of equitorsion holomorphically projective mappings of generalized Kählerian spaces we obtain five invariant geometric objects for these mappings.     

Mode coupling in chalcogenide-glass optical fibers

Using the time-independent power flow equation, we have examined the mode coupling caused by intrinsic perturbation effects in step-index As₂Se₃ chalcogenide-glass multimode optical fiber in the mid-infrared region. Results show that the coupling length where the equilibrium mode distribution is achieved depends on the wavelength and is of the order of kilometers.     

Investigation of structure and non-gradient turbulent transfer in swirling flows

Turbulence structure of swirling flows is being investigated in this paper, on the basis of experimental, self conducted measurements, and theoretical and numerical results. Turbulent swirling flows are extremely inhomogeneous, three dimensional and anisotropic. The aim of this paper is to investigate significant influence of swirl onto statistical parameters and non-gradient turbulent transfer. Contemporary optical measuring techniques two component laser Doppler anemometry (LDA) and stereo particle image velocimetry (SPIV) have been applied. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Explicit finite difference solution of the power flow equation in W-type optical fibers

Using the power flow equation, we have calculated spatial transients of power distribution and a steady-state distribution that are due to coupling of guided to leaky modes in W-type optical fibers (doubly clad fibers). A numerical solution has been obtained by the explicit finite difference method. Results show that power distribution in W-type optical fibers depends on both the intermediate layer width and the coupling strength. W-shaped index profile of optical fibers is effective in reducing modal dispersion and therefore in improving the fiber bandwidth. We have also shown that explicit finite difference method is effective and accurate for solving the power flow equation in W-type optical fibers.     

Frequency response in step-index plastic optical fibers obtained by numerical solution of the time-dependent power flow equation

The time-dependent power flow equation is employed to calculate frequency response and bandwidth in addition to mode coupling and mode-dependent attenuation in step-index plastic optical fibers. Frequency response is specified in the paper as a function of fiber length. Results are found to match reported measurements better than the existing analytical solution does. Mode-dependent attenuation and mode dispersion and coupling are known to be strong in plastic optical fibers, leading to major implications for their frequency response.     

Influence of the Wavelength on the Bandwidth in W-Type Plastic Optical Fibers

Journal of Russian Laser Research - We investigate the bandwidth and steady-state losses of multimode W-type plastic optical fibers solving the time-dependent power flow equation and show how the...