RESUMO
Grating couplers, widely used in Silicon Photonics (SiPho) for fibre-chip coupling are polarisation sensitive components, consequently any polarisation fluctuation from the fibre optical link results in spurious intensity swings. A polarisation management componentis analytically considered, coupled with a geometrical representation based on phasors and Poincaré sphere, generalising and simplifying the treatment and understanding of its functionalities. A specific implementation in SOI is shown both as polarisation compensator and polarisation controller, focusing on the operative principle. Finally, it is demonstrated experimentally that this component can be used as an integrated polarimeter.
RESUMO
We carried out a systematic study on the effect of nanocrystalline TiO2 paste formulations and temperature treatment on the performance of dye solar cells (DSCs) over a large temperature range, to provide useful information for the fabrication of both plastic and metal flexible devices. We compared conventional screen-printable and binder-free TiO2 pastes with a new formulation which includes hydroxylethyl cellulose (HEC), enabling the study of the effect of organic materials in the TiO2 layer in the whole 25-600 °C temperature range. Differently from the binder-free formulations where the device efficiency rose monotonically with temperature, the use of cellulose binders led to remarkably different trends depending on their pyrolysis and decomposition thresholds and solubility, especially at those temperatures compatible with plastic foils. Above 325 °C, where metal foil can be used as substrates, the efficiencies become similar to those of the binder-free paste due to effective binder decomposition and inter-nanoparticle bonding. Finally, we demonstrated, for the first time, that the simultaneous application of both temperature (110-150 °C) and pressure (100 MPa) can lead to a large improvement (33%) compared to the same mechanical compression method carried out at room temperature only.
