The paper presents an analysis of thermo-optic phase shifters in silicon-on-insulator (SOI) waveguide structures. It gives recommendations to provide high tuning characteristics at minimum power requirements. Then, this analysis is applied to the description of a novel type of reconfigurable optical add/drop multiplexer (ROADM) utilizing multi-reflector (MR) beam expanders and thermo-optic tuning in SOI structures. It is intended for use in high dense wavelength-division-multiplexing (HDWDM) flexible fiber-optic networks having multi-hundreds wavelength channels and advanced ITU grids (12.5 GHz, 25 GHz, 50 GHz).

In this article, we consider the magnetic interaction exerted on vortices in a thin YBa2Cu3O7−x film by a La0.67Sr0.33MnO3 layer. The magnetic coupling of the bilayer system was studied and locally imaged by means of magneto-optics. Twin boundaries in the LaAlO3 substrate cause a clear splitting of the manganite magnetic domains with well-defined in-plane magnetization separated by pinned out-of-plane magnetic structures. The vortices nucleated by the external magnetic field interact with the out-of-plane magnetic moments depending on their local structure and magnetic polarization. Different blocking mechanisms (sink or reservoir) are found for the vortex motion perpendicular to twin boundaries, whereas for vortices moving parallel to the out-of-plane magnetic structures either blocking or channelling effect is observed.

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This paper discusses the physical nature and the numerical modeling of a novel approach of periodic structures for applications as photonic sensors. The sensing is based on the high sensitivity to the cover index change of the notch wavelength. This sensitivity is due to the effect of abnormal blocking of the guided wave propagating along the silicon wire with periodic strips overhead it through the silica buffer. The structure sensing is numerically modeled by 2D and 3D finite difference time domain (FDTD) method, taking into account the waveguide dispersion. The modeling of the long structures (more than 1000 strips) is accomplished by the 2D method of lines (MoL) with a maximal implementation of the analytical feature of the method. It is proved that the effect of abnormal blocking could be used for the construction of novel types of optical sensors.