Ahtract -A computer-aided sjnthesis design procedure is given for nonuniform quadrature directional couplers in inhomogeneous media. A wiggly geometry is employed which effective11 slows the odd-mode phase veloci5 to match the even-mode phase velocity. The wiggly geometry results in improved isolation and increased effective dielectric constant. This technique provides a shorter coupler length ...

Soliton switching in a nonlinear directional coupler (NLDC) with Kerr nonlinearity and coupling constant dispersion (caused by intermodal dispersion between the symmetric and the anti-symmetric modes of the coupler) is studied using the well-known variational method. Switching characteristics are calculated and discussed. It is shown that the switching characteristics of the Kerr coupler for al...

Epitaxial multiferroic BaTiO₃-BiFeO₃ composite thin films exhibit a correlation between the magnetoelectric (ME) voltage coefficient αME and the oxygen partial pressure during growth. The ME coefficient αME reaches high values up to 43 V/(cm·Oe) at 300 K and at 0.25 mbar oxygen growth pressure. The temperature dependence of αME of the composite films is opposite that of recently-reported BaTiO₃...

We examine wave-front distortion caused by high-power lasers on transmissive optics using a Shack-Hartmann wave-front sensor. The coupling coefficient for a thermally aberrated Gaussian beam to the TEM(00) mode of a cavity was determined as a function of magnitude of the thermally induced aberration. One wave of thermally induced phase aberration between the Gaussian intensity peak and the 1/e(...

In a non-gyro micro inertial measurement unit (NGMIMU), the coupling error reduces the system measurement precision obviously. Based on the definition of the coupling error, a new static decoupling method applied total least squares (TLS) algorithm is proposed. TLS considers not only the error of accelerometer output, but also the calibrating error of the input signal arising from the couple fa...

In this Letter, we propose a generic nonlinear coupling coefficient, η(NL)²=η|γ/β₂|(fiber2)/|γ/β₂|(fiber1), which gives a quantitative measure for the efficiency of nonlinear matching of optical fibers by describing how a fundamental soliton couples from one fiber into another. Specifically, we use η(NL) to demonstrate a significant soliton self-frequency shift of a fundamental soliton, and we ...

In this paper, Turbulent mixed convective heat transfer of water and Al2O3 nanofluid has been numerically studied in a horizontal tube under non-uniform heat flux on the upper wall and insulation in the lower wall using mixture model. For the discretization of governing equations, the second-order upstream difference scheme and finite volume method were used. The coupling of pressure and veloci...

We study the time evolution of a chain of nonlinear oscillators. We focus on the fractal features of the spectral entropy and analyze its characteristic intermediate time scales as a function of the nonlinear coupling. A Brownian motion is recognized with an analytic power-law dependence of its diffusion coefficient on the coupling.

Tomographic images of the optical properties can be reconstructed using inversion algorithms for diffuse optical tomography (DOT); however, changes in the optode coupling that occurs while obtaining an object's measurements may often lead to the presence of artifacts in the reconstructed images. To reduce the number of artifacts induced by optode coupling, previous studies have introduced (unkn...

Understanding the characteristics of vessel traffic flow is crucial in maintaining navigation safety, efficiency, and overall waterway transportation management. Factors influencing vessel traffic flow possess diverse features such as hierarchy, uncertainty, nonlinearity, complexity, and interdependency. To reveal the impact mechanism of the factors influencing vessel traffic flow, a hierarchic...