Abstract: A device for responding to touch discrimination comprises an array of optical fibers distributed over a supporting substrate and a UV holographic processor is connected to the fibers rendering the fibers capable of responding to touch discrimination and location identification. The substrate is an artificial limb having the array of optical fibers thereon that have a density substantially similar to that of the human body. Wavelength comparators are associated with the optical fibers, the wave length comparators providing numerous sensing locations in a single fiber strand as part of a complete fiber optic network for mechanical actuation and sensory feed back.

Abstract: An evanescent filed based sensor uses a detector for sensing variations in properties of a fluid flowing in a boundary layer adjacent to the detector. The detector comprises an optical waveguide in the form of an optical fiber having a core layer covered by a cladding layer and having a substantially D-shaped cross section defining a planar surface with an optical grating pattern thereon. When a beam of laser light is directed through the detector as an input, variations in an output of the beam of laser light are indicative of changes in fluid pressure or density in the boundary layer or immediate region adjacent to the grating of the optical waveguide.

Abstract: Fiber optic sensors within the structure of an artificial body part resemble nerves in an organism which provide feedback on the condition of the entire system. An array of sensors deployed in various sub-structural components are also capable of performing health-monitoring functions in real time. Fiber sensors monitor strain and temperature and indicate excessive levels of either. This kind of application is particularly important to the producers and owners of such devices because of its facility for reducing accidental damage or personal injury. This patent outlines the development of in-line, distributed optical fiber microsensors for monitoring dynamic strain which is opto-electronically converted into touch and feel sensations in large and small scale artificial prosthetic devices.

Abstract: An evanescent filed based sensor uses a detector for sensing variations in properties of a fluid flowing in a boundary layer adjacent to the detector. The detector comprises an optical waveguide in the form of an optical fiber having a core layer covered by a cladding layer and having a substantially D-shaped cross section defining a planar surface with an optical grating pattern thereon. When a beam of laser light is directed through the detector as an input, variations in an output of the beam of laser light are indicative of changes in fluid pressure or density in the boundary layer or immediate region adjacent to the grating of the optical waveguide.

Abstract: An evanescent filed based sensor uses a detector for sensing variations in properties of a fluid flowing in a boundary layer adjacent to the detector. The detector comprises an optical waveguide in the form of an optical fiber having a core layer covered by a cladding layer and having a substantially D-shaped cross section defining a planar surface with an optical grating pattern thereon. When a beam of laser light is directed through the detector as an input, variations in an output of the beam of laser light are indicative of changes in fluid pressure or density in the boundary layer or immediate region adjacent to the grating of the optical waveguide.

Abstract: Apparatus for and methods of providing Bragg reflection filters in a receptor such as an optical fiber uses a wavelength tunable phase mask made of a non-linear material into which an interference pattern is written by a pair of converging laser light beams. The interference pattern is probed with a reading beam of laser light that creates diffraction orders which are read into the receptor. By changing the wavelength and amplitude of the writing beams that create the interference region in the phase mask, the characteristics of the Bragg reflection filter written into the optical fiber can be changed. Accordingly, if the optical fiber is indexed along the wavelength tunable phase mask while the characteristics of the interference region are changed, thousands of different Bragg reflection filters can be formed in a single optical fiber.

Abstract: An apparatus for preventing, detecting, and predicting the formation and propagation of cracks in structural members. The apparatus includes a plurality of strain sensors integrally formed with a patch to be fixed to an area on the surface of a structural member. The patch operates to reduce stress levels in the patch-covered area for deterring the formation or propagation of a crack therein. The sensors monitor changes in the strain field in the patch-covered area for detecting crack formation and detection. The apparatus may also include a temperature-compensating strain sensor and a temperature sensor both integrally formed with the patch for detecting and predicting crack formation and propagation, respectively.

Abstract: A Bragg reflection filter wavemeter is used to measure transverse holographic gratings and optical fibers and utilizes a first interferometer which is always fixed with respect to the optical fiber and a second adjustable interferometer. The optical fiber and first interferometer are mounted on a translating support while the second interferometer includes a pair of angularly adjustable mirrors for changing the angle at which the object and reference beams thereof intersect the fiber. Since the fiber is mounted on a movable support, the position of the support can be continually adjustable so that the reference and object beams always intersect the fiber at the same point, regardless of the angle assumed by the reflecting mirrors. The resulting interference patterns are projected by an objective lens to the far field in which a linear scanning, photodiode array is moved.

Abstract: An optical electronic multiplexing reflection sensor system for a plurality of Bragg sensors connected in series spaced relation in a plurality of single mode fiber optic cable buses. In each of the buses a unique address is provided each sensor function by wavelength selection. Each of a plurality of monochromators is coupled to a corresponding one of the buses and has a control connected to it for controlling the operation of the monochromator. A tunable laser source is coupled to each of the buses. A wavelength sweep generator is coupled to the laser source and provides outputs to the controls of the monochromators. Each of a plurality of photodetector receivers receives the output of a corresponding one of the monochromators and each has an output providing output signals indicating individual wavelengths of the Bragg sensors coupled to it. Each if a plurality of analog to digital converters is connected to the output of a corresponding one of the photodetector receivers.

Abstract: A low loss fiber optic coupler is fabricated by forming a coupler preform having a plurality of spaced glass cores extending longitudinally through a matrix of glass having a refractive index lower than that of the cores. The preform is heated and stretched to form a glass rod which is then severed into a plurality of units. Heat is applied to the central region of each unit while the ends of the unit are pulled apart to elongate and taper inwardly the heated central region, whereby the cores of the unit are more closely spaced and are of smaller diameter at the central region than they are at the ends of the unit. The unit is then provided with a plurality of optical fibers, one of which extends from each of the cores at the endfaces of the unit. A preferred method of providing the optical fibers involves forming the coupler preform of a matrix glass that is easily dissolved in a solvent.

Abstract: A low loss fiber optic coupler is fabricated by forming a coupler preform having a plurality of spaced glass cores extending longitudinally through a matrix of glass having a refractive index lower than that of the cores. The preform is heated and stretched to form a glass rod which is then severed into a plurality of units. Heat is applied to the central region of each unit while the ends of the unit are pulled apart to elongate and taper inwardly the heated central region, whereby the cores of the unit are more closely spaced and are of smaller diameter at the central region than they are at the ends of the unit. The unit is then provided with a plurality of optical fibers, one of which extends from each of the cores at the endfaces of the unit. A preferred method of providing the optical fibers involves forming the coupler preform of a matrix glass that is easily dissolved in a solvent.