Uniform stabilization of the damped Cauchy-Ventcel problem with variable coefficients and dynamic boundary conditions

In this paper, the uniform stabilization of the Cauchy-Ventcel problem with variable coefficients is considered, and the uniform energy decay rate for the problem is established by Riemannian geometry methods.     

Crosstalk pattern penalty reduction at 2.5 Gb/s in an SOA employing an assist light around gain transparency wavelength

We evaluate the inter-channel crosstalk in a semiconductor optical amplifier when injecting a high optical power continuous wave, as assist light, inside its active region around the gain transparency wavelength. In this work, the crosstalk of signal₁ (1535 nm) modulated at 2.5 Gb/s, has been induced by signal₂ (1560 nm) modulated at 2.5 Gb/s as well and having an optical input power of −7.5 dBm to simulate a multi-channel transmission. By measuring the bit error rate of signal₁, we show that the pattern penalty induced by the cross-gain modulation can be significantly reduced or even in certain conditions suppressed by the assist light.     

Composite liquid crystal-polymer electrolytes in dye-sensitised solar cells: effects of mesophase alkyl chain length

The doping of polymer electrolytes (PEs) with liquid crystal (LC) materials has been shown to improve the performance of dye-sensitised solar cells (DSSCs). This is achieved by promoting ionic conduction and increasing optical path length through multiple-light scattering within the photovoltaic devices. In LCs, it is well known that the length of the alkyl chain plays an important role since the LC morphology and mesophase stabilisation depend strongly on the alkyl group. In this work, liquid crystal-polymer composite electrolytes (LC-PEs) are prepared using nematic LCs with different alkyl chain lengths. The morphology of the LC-PEs is investigated and correlated with their electrical properties. Subsequently, DSSCs are prepared using the LC-PEs as a direct example of its application. It is shown that increasing the alkyl chain length of the LCs reduces the efficiency of the solar devices. The longer alkyl chains are speculated to intertwine, thus trapping the mobile ions and reducing the bulk ionic conductivity. For the same reason, longer alkyl chain LCs are thought to be unable to passivate the TiO₂ surface through the adsorption of cyanobiphenyl groups and hence the higher probability of back recombination reaction between the electrons in TiO₂ and PE.