Abstract:
An improved polarization preserving birefringent fiber optic member is provided having cross-sectional circular cladding and core members of soft glasses. A metallic coating of an approximately circular configuration, that is offset from the axis of the core and cladding members, is provided with sufficient thickness to provide an anisotropic variation in compressional strain on the core member to create the anisotropy of the refracted index of the core member for preserving polarization characteristics. The optical fiber can be formed by heating a mechanical composite of a core rod and cladding tube, drawing the core and cladding to form a fused fiber and transporting the drawn fiber through a coating bath to provide the variation in thickness.
Abstract:
An improved polarization preserving birefringent fiber optic member is provided having cross-sectional circular cladding and core members of soft glasses. A metallic coating of an approximately circular configuration, that is offset from the axis of the core and cladding members, is provided with sufficient thickness to provide an anisotropic variation in compressional strain on the core member to create the anisotropy of the refracted index of the core member for preserving polarization characteristics. The optical fiber can be formed by heating a mechanical composite of a core rod and cladding tube, drawing the core and cladding to form a fused fiber and transporting the drawn fiber through a coating bath to provide the variation in thickness.
Abstract:
An optical fiber (22) is tested for payout properties by supporting it on a payout support (24 ), preferably in the form of a hollow frustum of a cone, and attaching an unsupported end (26 ) of the optical fiber (22) to a projectile (42) that is thereafter propelled rapidly by expanding gas. The expanding gas is preferably generated explosively or by pressurizing the rearward end of the stationary projectile (42) and then releasing the projectile (42). A pneumatic gun (40) suitable for such testing has a barrel (44) sufficiently large to receive the projectile (42), a latching mechanism (60) that releasably engages the projectile (42), a closure (50) at the rearward end of the barrel (44) with a bore (58) therethrough concentric with the axis of the barrel (44) through which the optical fiber (22) passes and is drawn. The pneumatic gun (40) further includes a gas reservoir (48) that supplies a pressurized gas to the back side of the projectile (42). In operation of the pneumatic gun (40), the gas pressure is raised to a desired level with the projectile (42) latched, and then the latching mechanism (60) is released to permit the projectile (42), and attached optical fiber (22), to move rapidly forward as the gas expands.
Abstract:
Cylindrical rods of titanium carbide or other refractory material with uniform, high density are prepared by hot pressing plates from powders of the material, with a uniaxial pressing pressure applied to the broad faces of the plate. Bars of square cross section are then cut from the plate and machined to cylindrical rods. The process is particularly suited to the preparation of refractory material preforms to be used in single crystal growth by the float zone method. Titanium carbide rods having a highly uniform density of about 96% that of the theoretical maximum can be readily prepared and then grown into titanium carbide crystals.
Abstract:
An optical fiber fusion splicer apparatus (20) comprises a laser power source that produces a laser beam (32) having a laser beam axis (26). The laser power source includes a laser (22), a shutter (28) that controllably blocks and passes the laser beam, and an optical system (30) that expands the diameter of the laser beam. A parabolic mirror (34) has its axis coincident with the laser beam axis (26) and a bore (48) therethrough coincident with the laser beam axis (26). Optical fiber clamps (42, 46) hold the two optical fibers (40, 44) with their axes coincident with the laser beam axis (26) and their ends (62, 64) at the focal point (38) of the parabolic mirror (34). A sensor (82) measures the power reaching the optical fiber ends (62, 64) at the focal point (38) of the parabolic mirror (34), and a controller (72) controls the power level of the laser (22) responsive to the power measured by the sensor. The alignment of the optical fibers (40, 44) is sensed, preferably by a reflective device (74) that measures their internal reflectance or a video camera (68) that images their peripheries, and the optical fiber ends (62, 64) are aligned responsively.
Abstract:
A process is provided for the controlled growth of titanium carbide. Essentially, relatively fast, or low temperature growth, favors growth of single crystals having (100) orientation, while relatively slow, or high temperature growth, favors single crystals having (111) orientation. The process obviates the need for any seed crystals and permits growth of rods having diameters exceeding 1 cm.
Abstract:
A launching and regulation system that incorporates an expendable towing and deployment mechanism for use with a towed aerobody that provides for launching and controlled tow line payout between the towed aerobody and a towing vehicle. The system comprises a housing, a nonrotating spool disposed in the housing, and a tow line wound around the spool that is coupled between the aerobody and the vehicle. The tow line preferably comprises a photonic, fiber optic, link. The launching mechanism comprises a plurality of impulse cartridges for deploying the aerobody and severing the tow line at a predetermined time. A spring piston is disposed inside a wedge-shaped tube that confines expanding gasses within the tube that are generated by an impulse cartridge and moves the spring piston to launch the aerobody. The regulation mechanism may comprise a mechanical system or adhesive resin system. The mechanical system comprises a rotatable wedge-shaped tube, and the tow line is wrapped around it. A rotatable mechanical regulator is slidably coupled to the wedge-shaped tube. The regulator rotates with the tube and move transversely along the length of the tube as the tow line unwinds. A brake mechanism and a brake drum are provided to control payout of the tow line. The adhesive resin system comprises an adhesive resin coating disposed on the tow line that has an adhesion coefficient that permits it to peel off of the spool at a predetermined rate. Either regulation system provides the ability to control the rate at which the tow line comes off of the spool such that tow line tension is regulated during deployment. A severing mechanism is provided for severing the tow line using an impulse cartridge.
Abstract:
There is disclosed a metallic clad glass fiber optical waveguide suitable for use as a high-strength optical transmission line, e.g., for high capacity communications systems and for sensors operating at high temperature. At least two metallic claddings or coatings are formed on the glass waveguide structure, which comprises a core and glass cladding, by coating the glass fiber with at least one of the metallic coatings as it emerges from the furnace with a metal or alloy. The first metal or alloy employed is one that is substantially chemically inert with respect to the material comprising the glass fiber at the deposition temperature during coating of the metal or alloy onto the glass fiber. The second metallic coating may be of the same composition as the first, in order to repair pinholes or to increase the thickness. Alternatively, the second metallic coating may be of a different composition than the first in order to provide the waveguide with mechanical properties that are different than either layer alone could provide. Specific electrical and magnetic properties may also be provided. The metallic coatings prevent chemical or mechanical damage to the glass surface. A plastic coating is optionally provided for additional protection of the metallic surface.
Abstract:
Alloys suitable for use in liquid metal field ionization ion sources are provided. Such sources include an anode electrode for supporting an ion emitter comprising an alloy in the liquid state. The source further comprises means for generating an ionizing electric field and a reservoir for the liquid metal, ions of which are to be emitted by the source.The alloys are selected from the group consisting of (a) metal-metalloid alloys comprising about 10 to 30 atom percent of at least one metalloid element, the balance at least one transition metal element, (b) early transition-late transition alloys comprising about 30 to 85 atom percent of at least one early transition metal, the balance at least one late transition metal, and (c) Group II alloys comprising about 35 to 80 atom percent of at least one Group II element, the balance at least one metal element.Ions generated in liquid metal ion sources form a high brightness ion beam, which permits focusing a beam of emitted ions to a submicrometer spot. The ions may be used to alter material properties by ion implantation such as to dope semiconductors, to form ohmic contacts, to improve wear and corrosion resistance in metal surfaces and by sputter etching thin films such as metals, dielectrics and semiconductors.
Abstract:
A mechanical regulation system for controlling tow line payout between the aerobody and a towing vehicle. The system comprises a housing, a nonrotating spool, and a tow line wound around the spool that is coupled between the aerobody and the vehicle. The regulation portion of the present system comprises a rotatable wedge-shaped tube, having the tow line wrapped around it. A rotatable mechanical regulator is slidably coupled to the wedge-shaped tube. The regulator is adapted to rotate with the tube and move transversely along the length of the tube as the tow line is removed from the spool. A brake mechanism is provided as part of the regulator, and a brake drum is disposed adjacent the periphery of the regulator that is contacted by the brake mechanism.