Abstract: This invention is a quasi-static fiber pressure sensor using self-referenced interferometry based on a broadband semiconductor source which probes the pressure plate deflection within a Fabry-Perot cavity where phase is demodulated with a dual grating spectrometer providing real-time, high resolution remote measurement of pressure using optical interrogation of a deflecting pressure plate. This technique yields absolute gap measurement in real time over a wide range of gap lengths with nanometer resolution. By tailoring the pressure plate design to cover the range of gaps and deflection that can be resolved, pressure sensing with psi resolution can be obtained in a kpsig pressure range.

Abstract: The fiber-optic magnetostrictive transducer system consists of a sensing element having three dual-strip fiber optic magnetostrictive transducers bonded into a single fiber Mach-Zehnder interferometer operating single mode mounted in a symmetrical orthogonal geometry. The dual-strip fiber optic magnetostrictive transducers have predictable and consistent reproducibility and are comprised of a pair of field annealed metallic glass strips bonded to a coil of optical fiber. This structure is in turn mounted on a bobbin structure where the fiber ribbon is attached to the bobbin only at the two ends of the bobbin. This reduces the possible loading of the transducer due to friction between the optical fiber and the surface of the mounting structure and at the same time provide a long sensing fiber in contact with the magnetostrictive element for high sensitivity.

Abstract: A method and apparatus for transforming an obscured beam into a uniform intensity pattern at the image plane of the apparatus are described. Apparatus for carrying out the invention comprises two on-axis optical elements which are designed for stigmatic imaging of an incoming obscured parallel laser beam. The first element, a paraboloid mirror, forms an imaginary stigmatic image of the beam at its focal point. The second element, a multi-faceted mirror, comprises identical flat facets disposed on an ellipsoid envelope. The ellipsoid conjugates the focal point of the paraboloid and the image plane. Selection of an image shape and dimension defines the shape and dimension of the facets. Each facet's contribution to the image is a full scale centered spot. The contribution of each facet add up to form a final uniform image. Slight variation of the image dimension, from facet to facet, allows a roll-off of the image and compensates for diffraction ripples by the edges of the facets.