Narrow Results

We propose a new design to achieve optical waveguide switch. We construct a photonic crystal waveguide with one yttrium iron garnet (YIG) rod array on the two sides of the waveguide. Through the mode analysis, we find in special frequency range a few YIG rods under magnetic field can form the magnetic reflectance wall that blocks the light flow. Removing the magnetic field will delete the reflection wall and let the blocked light to be switched on.

We consider a discrete model that describes a linear chain of particles coupled to two defects. This model can be regarded as a linear generalization of the familiar Fano–Anderson model. The analytical result for the plane wave transmission coefficient is obtained. Comparing the transmission coefficient of Gaussian wave with that of plane wave, we can draw a conclusion that arising perfect reflection due to destructive interference depends on the input waveform of incident particle and a necessary switching condition of Fano resonance is the input plane wave. This interesting feature may play a guiding role in devising various particle switches in theory and experiment.

We analyze and propose an all-optical switch working over the C-band of the International Telecommunication Union (ITU), which is based on nonlinear switching cells made of photonic crystal (PhC). Indeed, the nonlinear switching cells are directional couplers (DCs) embedded in PhC, which can work over the C-band of the ITU (wavelength from 1530 to 1565 nm). The nonlinear switching method uses a relatively low-power external command signal for obtaining nonlinear effects. This external command signal is inserted in the central coupling region of the DC, which acts as another waveguide. The switching process is based on the change from the cross state to the bar state owing to the external command signal. In our simulations we used the plane-wave expansion (PWE), finite-difference time-domain (FDTD), and our own binary propagation method (BiPM).

A gas trigatron type gap for a 36-channel ring switch of a five-cascade water-insulated double step forming line with output impedance of 2.9 Ohm “Gamma-1” high-current electron accelerator is described in this paper. At discharge operating voltage of 1 MV its overall dimensions are: height ~ 160 mm, diameter ~ 240 mm. When operated with a mixture of insulating gas and nitrogen in proportion 40%SF₆+60%N₂ at 17 MPa pressure, the trigger delay is (16 ± 2) ns, with a self-break safety margin of not less than 1.5. The gap electrode surfaces are made of tungsten alloy. When operating as a part of the double step forming line switch, the average energy, switched through a single gap, is 3.3 kJ, and the current is 95 kA.