Abstract: A device includes a nanocomposite film, itself, having at least one nano-particle layer and at least one crosslinker layer. The device also includes an abrasion resistant coating over the nanocomposite film. A method for producing a device with an abrasion resistant nanocomposite coating on a substrate having a nano-particle-coated surface involves contacting nano-particle-coated surface with a crosslinker such that a chemical bond forms with nano-particles within the nano-particle-coated surface and this chemically bonded crosslinker is then contacted with at least one compound such that the at least one compound chemically binds to the crosslinker thereby forming an abrasion resistant coating on the substrate having the nano-particle-coated surface.

Abstract: We make a substrate biocompatible by contacting it with a starting material and initiating alternating charge layer electrostatic self assembly to form a thin film. Starting materials may be poly(vinylpyrrolidone), poly{bis-(carboxylatophenoxy)phosphazene}, poly(methacrylic acid), poly(l)-lysine, poly(ethylene glycol), poly(D-glucosamine), poly(l-glutamic acid), poly(diallyldimethylamine), poly(ethylenimine), hydroxy fullerene, long-sidechain fullerene, or other polymers that participate in electrostatic self-assembly. The thin film fabrication advantageously may be at room temperature. A biocompatible thin film that is uniform and homogeneous can be provided. Optionally, ZrO2, Al2O3 or TiO2 nanoclusters also may be used in the film assembly. The film may be used in a drug delivery device or a medical device. The film may be used for tissue engineering.

Abstract: The invention describes a procedure for manufacturing photonic crystals and passive and active optoelectronic device components comprising of photonic crystals. The manufacturing approach draws upon the mature technology of producing microchannel plates (MCPs). Based on this manufacturing approach, photonic crystal structures with or without defects can be fabricated. The photonic band gaps produced in the presented invention can be made passive or active. A photonic crystal structure is described that contain different photonic band gap regions. Additionally, photonic crystal structures filled with different refractive indexes are described. The photonic crystals of the present invention maybe used as filters, phase shifters, splitters, couplers, multiplexers, demultiplexers, modulators, variable optical attenuators, gain equalizers, etc. for optical communication applications.

Abstract: Described are the design of a rare earth iron garnet sensor element, optical methods of interrogating the sensor element, methods of coupling the optical sensor element to a waveguide, and an optical and electrical processing system for monitoring the polarization rotation of a linearly polarized wavefront undergoing external modulation due to magnetic field or electrical current fluctuation. The sensor element uses the Faraday effect, an intrinsic property of certain rare-earth iron garnet materials, to rotate the polarization state of light in the presence of a magnetic field. The sensor element may be coated with a thin-film mirror to effectively double the optical path length, providing twice the sensitivity for a given field strength or temperature change. A semiconductor sensor system using a rare earth iron garnet sensor element is described.

Abstract: An electrostatic self-assembly method of fabricating electrostrictive and piezoelectric thin film assemblies not only provides a thinner film than is attainable by conventional methods, but provides excellent molecular-level uniformity and precise structural control, and thus large, effective piezoelectric coefficients. The method produces a thin film assembly including (a) a substrate, and (b) a film having one or a plurality of layers disposed upon the substrate, wherein at least one of the layers includes a dipolar material, and this layer of dipolar material has a uniform thickness of at most 500 nm.

Abstract: We make a substrate biocompatible by contacting it with a starting material and initiating alternating charge layer electrostatic self-assembly to form a thin film. Starting materials may be poly(vinylpyrrolidone), poly{bis-(carboxylatophenoxy)phosphazene}, poly(methacrylic acid), poly(l-lysine), poly(ethylene glycol), poly(D-glucosamine), poly(l-glutamic acid), poly(diallyldimethylamine), poly(ethylenimine), hydroxy fullerene, long-sidechain fullerene, or other polymers that participate in electrostatic self-assembly. The thin film fabrication advantageously may be at room temperature. A biocompatible thin film that is uniform and homogeneous can be provided. Optionally, ZrO2, Al2O3 or TiO2 nanoclusters also may be used in the film assembly. The film may be used in a drug delivery device or a medical device. The film may be used for tissue engineering.

Abstract: A pyrometer for measuring the temperature of an object with high accuracy and fast response time that uses both multi-wavelength pyrometry techniques and nanotechnology. Radiance from an object is transmitted through a fiber optic cable, is received by a thin-film multi-wavelength modulator, and is detected by an optical detector array. More specifically, the pyrometer includes means for conveying light; an optical lens; an optical fiber; means for optically modulating the wavelength of light; means for optically detecting the modulated light; means for transforming the optically detected wavelengths into electrical signals; and means for processing and recording the electrical signals. The means for optically modulating the wavelength includes at least one piezoelectric film deposited by an electrostatic self-assembly method.

Abstract: Abrasion and scratch protective coatings magnetic coatings, electrically and thermally conducting coatings, and UV absorbing coatings are provided by electrostatic self-assembly (ESA) of one layer of an organic or polymer molecule and one layer of inorganic clusters in a layer by layer fashion at room temperature. A combination of inorganic clusters having a particle size of preferably less than 30 nm and flexible organic molecules allows fabrication of films tens to hundreds of micrometers thick, with large pores and excellent stress relaxation.

Abstract: Uniformity of optical coupling of optical elements such as couplers and splitters is improved by heat treatment which causes dopants in the core of an optical fiber to diffuse into material from the cladding layer of the optical fibers from which the optical element is formed, resulting in a substantially homogeneous interior region of the star coupler or splitter. Increased lossiness of the optical element thus formed may be limited by termination of the heat treatment before dopant diffusion reaches equilibrium throughout the fibers so that a portion of the cladding layer of the fibers remains surrounding the substantially homogeneous region where the fibers have been fused together. Dopant diffusion is constrained to a substantially radial direction in each fiber by uniformity of heating over a region where at least two fibers are twisted together.

Abstract: Uniformity of optical coupling of optical elements such as star couplers and splitters is improved by heat treatment which causes dopants in the core of an optical fiber to diffuse into material from the cladding layer of the optical fibers from which the optical element is formed, resulting in a substantially homogeneous interior region of the star coupler or splitter. Increased lossiness of the optical element thus formed may be limited by termination of the heat treatment before dopant diffusion reaches equilibrium throughout the fibers so that a portion of the cladding layer of the fibers remains surrounding the substantially homogeneous region where the fibers have been fused together.

Abstract: A fiber optic sensor is fully compensated for light source intensity variation, fiber losses and modal power distribution by providing input to one end of an optical fiber from a relatively broad band light source containing at least two spectrally separated wavelengths. At least one of these spectrally separated wavelengths is reflected back into the optical fiber by a filter located between a second end of the optical fiber and a reflective transducer. The filter is preferably of the interference edge filter type and has a nominal cut-off wavelength within the spectral band of the light source or between the two spectrally separated wavelengths. Therefore, the paths traversed by light of the spectrally separated wavelengths will differ only by twice traversing the reflective transducer. Temperature measurement or compensation can also be provided by sensing of reflected light intensity or power at approximately the nominal cut-off frequency of the filter.

Abstract: The fibers are bound together about 1 cm apart. An oxy-propane torch is used to heat the fibers so that they fuse together. At the same time, the two relatively movable translational stages to which the fibers are clamped are pulled apart to form a biconical tapered region in the fibers. The fibers are tapered until a desired coupling ratio is achieved. After the insertion loss is measured, the torch is reintroduced into the taper region and one side (e.g., the right side) of the taper region is rotated with a minimal increase in the taper length, i.e., the distance between the two stations is increased only enough to keep an even tension in the taper region.

Abstract: An extrinsic Fizeau fiber optic sensor comprises a single-mode fiber, used as an input/output fiber, and a multimode fiber, used purely as a reflector, to form an air gap within a silica tube that acts as a Fizeau cavity. The Fresnel reflection from the glass/air interface at the front of the air gap (reference reflection) and the reflection from the air/glass interface at the far end of the air gap (sensing reflection) interfere in the input/output fiber. The two fibers are allowed to move in the silica tube, and changes in the air gap length cause changes in the phase difference between the reference reflection and the sensing reflection. This phase difference is observed as changes in intensity of the light monitored at the output arm of a fused biconical tapered coupler. The extrinsic Fizeau fiber optic sensor behaves identically whether it is surface mounted or embedded, which is unique to the extrinsic sensor in contrast to intrinsic Fabry-Perot sensors.

Abstract: Tapered two-mode optic fibers are used as sensors with sensitivity varying as a function of length. The optical fiber sensors act as vibrational-mode filters thereby performing initial signal processing of the sensor signal. The sensors are based on the differential propagation constant in a two-mode fiber that is directly dependent on the normalized frequency or V-number. Tapering the fiber changes the V-number and hence can change the sensitivity of the sensor along its length. By choosing an appropriate weighting function in the manufacture of the sensor, it is possible to implement vibrational-mode analysis, vibrational-mode filtering and other functions that are critical in control system applications.

Abstract: Optic fiber coupler fabrication stations allow one-step packaging and reduce fabrication time. The optic fiber coupler fabrication stations produce a single piece construction of the coupler package with improved uniformity. Two linear translation stages are driven in opposing directions using left and right hand threaded rods connected to a common drive shaft driven by a small electric motor. Fibers to be coupled are clamped into the station to provide the necessary tension during the tapering process. The fibers are tied together using cotton thread, and an oxy-propane torch is used to fuse the fibers together while the two translation stages pull the fibers to form a biconical tapered region in the fibers.

Abstract: Two-mode, elliptical-core optic fibers with a permanent photo-induced index change are used as sensors with sensitivity varying as a function of length. The optic fiber sensors act as vibrational-mode filters thereby performing initial signal processing of the sensor signal. The sensors are based on photo-induced refractive index changes. These refractive index changes affect the differential phase modulation between the LP.sub.01 and the LP.sub.11.sup.even modes. The change in beat-length is dependent on the amount of strain induced in the fiber while the grating is being formed. The pattern is thus varied along the length of the fiber by straining the fiber in a specific fashion while the grating is being written. This changes the sensitivity, of the sensor along its length. By choosing an appropriate weighting function in the manufacture of the sensor, it is possible to implement vibrational-mode analysis, vibrational-mode filtering and other functions that are critical in control system applications.

Abstract: The present invention pertains to a strain sensor. The strain sensor is comprised of an optical wave guide, a device for providing optical pulses to the optical wave guide and a device for sensing localized strain in the optical waveguide. The sensing device determines shifts in arrival times of the optical pulses at the sensing device that correspond to the localized strain. The apparatus includes a light source, a light detector, and a waveguide connecting the source with the detector. The apparatus also includes means for generating light pulses from the source through the waveguide and means for repeatedly propagating at least one of the light pulses in a closed loop. The light source detects arrival times of the light pulses.

Abstract: A robot gripper control system is disclosed which uses PVDF piezoelectric sensors to actively damp exerted force. Instead of charge amplifying the output of the piezoelectric transducer, the output voltage is measured as the charge drains across a path of low resistance. Thus, the sensor output is proportional to the rate-of-force exerted by the gripper. The PVDF sensor and a strain gauge are arranged in a proportional and derivative (PD) control system for the control of force of a robot manipulator hand. Experimental results for the particular disclosed gripper indicate that as much as 900% improvement in force step response rise time and a 300% reduction in overshoot are possible through the use of the PVDF sensor.

Abstract: An optical fiber device for allowing local measurement of temperature or strain using pulse amplitude techniques. The apparatus includes a fiber splice having a high temperature epoxy or solder to secure the opposing fibers in spaced relationship within a metal tube. By applying heat or stress to the tube the load causes the air gap to open or close which in turn varies the amount of light transmitted. By utilizing apparatus to measure the change in the amplitude affected by changes in the air gap, one can measure ultimately the strain or temperature imposed on the device.

Abstract: The present invention pertains to a strain sensor. The strain sensor is comprised of an optical waveguide, a device for providing optical pulses to the optical waveguide and a device for sensing localized strain in the optical waveguide. The sensing device determines shifts in arrival times of the optical pulses at the sensing device that correspond to the localized strain. In a preferred embodiment the sensing device includes a device for reflecting a portion of the optical pulses at predetermined positions in the optical waveguide and a device for detecting the shift in arrival times of the portion of the optical pulses which are reflected.