Papers by Author: Nicholas M. White

Abstract: We review our progress in developing single-mode tellurite glass holey fiber for infrared nonlinear applications. Tellurite glass preforms with complex holey structure were fabricated by using glass extrusion technique. The fabrication of single-mode tellurite holey fibers with the effective mode area ranging from 2.6-3000mm2 and the effective nonlinearity γ ranging from 0.23- 280W-1km-1 were demonstrated. By controlling the microstructured features in the holey cladding, the dispersion profile and the zero dispersion wavelength of this type of single-material optical fiber were tailored within a broad range. Broadband supercontinuum spectra from 0.9 to 2.5mm were generated from the fabricated fibers by using femtosecond laser. Attenuations due to the impurities, such as transition metal ions, rare-earth ions and hydroxyl groups, were also investigated in the bulk tellurite glass and fiber from visible to mid-infrared regimes.

Abstract: A joint Brunel-Southampton Universities’ research team has developed digital strain gauges based on a metallic triple-beam resonator structure with thick-film piezoelectric sensor elements. The resonator, an oscillating structure vibrating at resonance, is designed such that its resonant frequency is a function of the measurand. The resonator substrate was fabricated by a double-sided photochemical etching technique and the thick-film piezoelectric elements were deposited by a standard screen-printing process. The new metallic digital strain gauges can be used on stiff structures, have high overload capacities, low power consumption, frequency output for digital processing, and offer prospects for wireless-batteryless operation. The device can be easily mass-produced at low cost for use in a wide range of measuring systems, e.g. load cells, weighing machines, torque transducers and pressure sensors.