Abstract: An optical directional coupling apparatus includes an optical directional coupling device for permitting light of a predetermined polarization direction to be emitted from a second port when it is received at a first port of the coupling device, and for permitting only a light component of a polarization direction at a given angle with respect to the first polarization direction to be emitted from a third port when light is received at the second port. A polarization maintaining single mode fiber, is coupled at one end to the second port and has a main axis set at a predetermined angle with respect to the first polarization direction, wherein an optical fiber to be measured is connected at one end to the other end of said polarization maintaining single mode fiber.

Abstract: Narrow band, wavelength selective optical coupling is achieved in a device including first and second optical transmission media and a filter. The first and second optical transmission media are in substantially close proximity of each other in a predetermined interaction region to provide evanescent coupling therebetween. The filter is positioned on the first optical transmission medium in the predetermined region for causing the coupling to be wavelength selective and contradirectional from the first optical transmission means to the second optical transmission means. One exemplary embodiment of the coupler includes optical fibers as the transmission media and a Bragg reflection grating integrally formed on the first transmission medium as the filter. Other embodiments include the use of semiconductor waveguides as the optical transmission media.

Abstract: An optical coupling device for coupling a first optical waveguide having an end face and transmitting a number N of signals of different wavelengths with a number N of further optical waveguides having end faces and each transmitting one of these signals comprises means for the spectral selection of these signals, which means include a wavelength separator with interference filters, and means for the spatial selection of these signals in order to achieve this coupling.

Abstract: It is disclosed that a radiation-resistant optical conductor, such as an optical fiber for telecommunication, a multiple fiber for an image scope, and a light guide for illumination, which comprises a core composed of a pure silica glass which is prepared via an ultrahigh temperature of at least 3,000.degree. C. and has an OH group content of from 0.1 to 300 ppm, and a cladding layer formed on the core, and the cladding layer being composed of a silica glass which contains boron element and fluorine element as a dopant.

Abstract: A receiver for modulated optical signals including a multiport optical fibre coupler arrangement (10) to one input port of which the modulated optical signals are applied and to another input port of which a local oscillator optical signal of substantially the same optical frequency as the modulated optical signal is applied whereby the output ports of the coupler give separate output signals that are differentially related to the optical frequency phase difference between the modulated input signal and the local oscillator signal, means for individually demodulating (12a-12c) the output signals and means for summing the demodulated output signals.

Abstract: An integrated optics optical polarization conversion device comprising a guide structure formed by integrated optics in a flat substrate made from a uniaxial crystalline material having electro-optical properties in which two distinct modes may propagate. In accordance with the invention, the optical axis of the crystal of said substrate forms an angle with the plane of the substrate less than (.pi./2) radians. In one of the variants, said axis is parallel to the direction of propagation of the guided wave and the device comprises a single set of homogeneous electrodes.

Abstract: Electrooptical directional coupler with traveling wave and alternating phase shift. This coupler comprises a central electrode in the form of microstrip (MB) of width W and two lateral electrodes (BL1, BL2) very wide in comparison with W. The propagation line then is asymmetrical.

Abstract: An optical fiber cable includes a core (22) comprising at least one optical fiber, a plastic tubular member (28) which encloses the core, a jacket (54) which encloses the tubular member and a prefabricated strength system which is interposed between the jacket and the tubular member. The strength system includes a carrier tape (82) which may be comprised of woven glass or impregnated woven glass, for example, and which is wrapped longitudinally about the tubular member. The carrier tape has an adhesive material disposed on one surface thereof for causing a plurality of longitudinally extending strength members (86--86) to remain attached to the tape while the jacket is being extruded over the strength system. In one embodiment, a metallic shield system (52) is disposed about the tubular member and the prefabricated strength system is disposed in engagement with an outer surface of the shield system.

Abstract: The present invention relates to an optimized guided wave microwave or lightwave communication system or network wherein a plurality of directional couplers (14, 17) (a) are disposed along a bus-like wave guiding means (13, 16), and (b) include separate coupling coefficients which are optimized. More particularly, the present invention relates to a guided wave communication system or network including, for example, a head-end unit (15) which is coupled to one end of a bus-like wave guiding means. Separate directional couplers are disposed along the wave guiding means to couple lightwave or microwave signals either (a) into the bus-like wave guiding means (13) from separate transmitters (11), or (b) from a bus-like wave guiding means (16) to separate receivers (12).

Abstract: A fiber optic transducer is provided for use in remote monitoring of the position of mechanical devices, such as the position of valves used in the petroleum and chemical industries and the like. The fiber optic transducer includes a transducer frame supporting an optical fiber under conditions of predetermined bending and tension. Cam apparatus is coupled between a mechanical device to be monitored and a bending pin having a cylindrical surface bearing against the fiber to control further bending thereof in response to position changes of the mechanical device. Changes in light transmission through the fiber as a result of bending can be detected and correlated with the position of the mechanical device.

Abstract: An electrically controlled integrated optical switch having a body made up entirely of crystalline silicon. More specifically, the body has a pair of channel waveguides intersecting in an X-like configuration forming therein an intersection crossover region. A first electrode is positioned on the intersection crossover region and a second electrode is positioned on the bottom of the body opposite the intersection crossover region. A controllable current/voltage source is electrically connected to the electrodes in order to alter the index of refraction of the intersection crossover region in order to change the amount of optical cross coupling of light between the intersecting waveguides.

Abstract: Hydrogen absorbing mixtures for protecting optical fibers from damage by hydrogen and optical fiber telecommunication cables containing such a mixture or mixtures. The mixture includes at least one oxide selected from oxides of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, cerium, tin, lead and wolfram, at least one catalyst selected from among the transition metals, the inorganic and organic compounds of the transition metals and the complexes of the said transition metals, both by themselves as well as supported by inert materials, and an anhydrous salt which, on chemically reacting with water, forms crystalline hydrated compounds which are stable at temperatures up to at least 90.degree. C. The anhydrous salt may be one or more of anhydrous calcium sulfate, anhydrous calcium chloride, anhydrous sodium sulfate and anhydrous copper sulfate.

Abstract: A submarine cable with optical fibers which prevents damage to the fibers due to water pressure without the use of an external armor. The cable has a central core with a strand which provides the cable tensile strength and which is surrounded and contacted by a layer of plastic material which has helical grooves which receive the optical fibers which may have a protective covering. The layer of plastic material is surrounded by sheath in the form of a layer of plastic material. The grooves and any spaces radially inwardly of the sheath, such as the spaces between the wires of the strands, are filled with a substantially incompressible fluid, such as a grease or jelly. If the optical fiber protective layer is a tube loosely receiving the optical fiber, or optical fibers, the space within the tube not filled by optical fibers is filled with a substantially incompressible fluid. The layer of plastic material forming the sheath may at least partially extend into the grooves.

Abstract: A technique is disclosed for aligning a packaged optical emitter with its associated transmission fiber which provides peak power coupling between the emitter and the fiber. The technique uses a connectorized coherent fiber bundle which is inserted in the fiber connecting portion of the package such that it accepts the emitter output radiation at the same Z-axis position as the single fiber it simulates. The fiber bundle has a fiducial marking on one end which coincides with the core region of the single fiber. Both the emission pattern and the fiducial marking are displayed on a video monitor and the emitter subassembly is moved around inside the package until the emission pattern coincides with the fiducial, thus indicating alignment of the emitter with the associated transmission fiber.

Abstract: A retroreflectivity measuring system measures performance data relating to a reflective surface, such as a highway stripe or marking containing reflective glass beads. A laser beam illuminates a portion of the reflective surface with radiation of a predetermined wavelength, the laser being incident on the surface at an incidence angle i. The incident laser beam is then reflected back, at least partially, at a particular observation angle o that is separated from the incidence angle by a divergence angle .delta.. A telephotomultiplier aimed at the illuminated area receives the reflected laser beam at the observation angle o. A preferred telephotomultiplier includes a telescope, a narrow pass optical filter for passing basically only the wavelength of the laser beam, and a sensitive photoelectric device, such as a multiplier phototube. The laser and the telephotomultiplier may be mounted on a servo-motor driven frame in order to scan the target area from a moving vehicle.

Abstract: A biconic connector includes two plugs (44--44) each of which terminates a single fiber optical cable (55) and each of which includes a conically shaped end portion (50). The connector also includes an alignment sleeve having back-to-back conically shaped cavities each of which is adapted to receive an end portion of a plug. In order to minimize loss through a connection, it becomes important for the axis of the end portion of the core of the optical fiber in the conically shaped end portion of the plug to be coincident with the axis of revolution of the conically shaped end portion. This is accomplished by holding the plug in a fixture such that its conically shaped end portion is exposed and the fixture adapted to be turned about an axis of rotation. Images of light launched into the optical fiber are acquired in two planes at a plurality of positions spaced apart along a reference axis.

Abstract: The present invention is a high-pressure sapphire cell designed to measure the properties of a petroleum reservoir fluid sample. It comprises at least two sapphire anvils, a pressure vessel having inlet and outlet parts, gaskets between the anvils and the pressure vessel; and a means for forcing the anvils together to form a fluid-tight seal between the anvils and the pressure vessel. Once a fluid sample enters the pressure vessel, a high pressure environment similar to a petroleum reservoir is created by an outside pressure pump via a pressure inlet tube. It is in this state that the fluid measurements are made on the sample.

Abstract: An FSK demodulator of the differential type is arranged to provide two versions of an input FSK signal that, relative each other, (1) have a linear phase shift versus frequency characteristic and (2) are phase shifted by 90 degrees at a center frequency halfway between the upper and lower FSK frequencies. The linear phase shift is provided by an N sample delay element, while a constant phase shift circuit which includes a K factor gain element provides the 90 degree phase shift. By virtue of this arrangement, the demodulator characteristics can be adaptively varied and the demodulator tuned simply by changing the value of K. A similar adaptive technique is applied to a threshold detector arranged to position a threshold midway between the extremes of an input signal.

Abstract: A design of optical fiber cable that is gas blocking has a set of four plastics packaged optical fibers (2) around a central strength member (1). The fibers and strength members are embedded in spaced apart relationship in a nylon 12 pressure extruded sheath (3) which has been annealed to provide a contraction in the region of 1/4%.

Abstract: An optical fiber unit consists of one or more optical fibers configured to provide an optical function, a preformed internal protective body having a preformed space into which the fiber(s) extend with a relatively close fit, the internal protective body being of a material of hardness and coefficient of thermal expansion substantially matched to that of the fiber(s) and the fiber(s) being bonded thereto, an outer protective body surrounding the internal protective body, at least a portion of the outer protective body having a preformed recess shaped to receive and support the rigid internal protective body, a mass of relatively soft uniting material disposed in a manner to secure the internal protective body to the preformed portion of the outer protective body, an injection-molded portion of the outer protective body, of substance less brittle than the internal protective body, effectively surrounding and protecting the internal protective body and the fiber(s) therewithin from the environment in which the