A novel ultra-compact resonator for Superconducting thin-film filters

This paper proposes a novel thin-film resonator structure, which combines the microstrip resonator and the coplanar resonator to form an integrated resonator. This resonator structure has an extremely compact size, as compared to the thin-film resonator structures from the literature, and its resonant frequency was shown theoretically to be less sensitive to, or even insensitive to, the thickness of the substrate. An eight-pole quasi-elliptic filter based on this novel resonator was designed. The exact filter layout was simulated and optimized by full-wave electromagnetic simulation using IE3D software. The full-wave simulated filter response was in good agreement with the theoretical filter response. A filter was fabricated on a double-sided YBa/sub 2/Cu/sub 3/O/sub 7/ thin film epitaxially grown on a 2-in-diameter MgO wafer. The measured filter response showed a bandwidth of 1.5 MHz and a center frequency of 850.3 MHz at 78 K. The insertion loss at the passband center was 1 dB, corresponding to a filter Q of 28 000. Steep rejection slopes were obtained at the band edges and rejections reached over 70 dB in approximately 300 kHz from the passband edges. No pronounced changes were observed for input power levels between -20-0 dBm, indicating a relatively high power-handling capability of the filter.     

Optical phase conjugation and nonlinear optical bandpass filtercharacteristics in CdSSe microcrystallite-doped glass

Experimental measurements of the backward CW four-wave mixing response in semiconductor-doped glass in a regime important to applications are described. In particular, it is shown that lowering the operating temperature to 125 K yields a χ³≈2×10 ^-4 ESU. Aberration correction through optical phase conjugation is demonstrated with a phase conjugate reflectivity of 0.3% along with a wide-angle field-of-view response. In addition, the nearly-degenerate four-wave mixing response of importance to tunable bandpass optical filters is reported     

Cristallisation du trihydrate d'alumine: Un modèle pour l'attrition

The breakdown of alumina trihydrate particles was studied in a batch isothermal stirred reactor. Experiments were performed using mono-dispersed particles. Crystal size distribution of precipitate was evaluated to study the variation of the number of particles as a function of time. Experimental results were used to develop a mathematical model for the breakdown phenomena. The new data obtained are applicable for simulation of industrial crystallizers in the aluminum industry.