Abstract: The invention relates to an electrical overhead cable rope comprising an integrated optical communication lead (13), in which metallic wire elements (14, 15, 16) surround a tube (1) or noble steel, in which at least one optical waveguide (2) is contained. Corrosion of the wire elements of the overhead cable rope is prevented by providing a tube (1) of noble steel having applied to it a water-tight coating which establishes a continuous electrically conducting connection between the tube of noble steel and the wire elements (14, 15, 16) surrounding it.

Abstract: Heterodyne optical time domain reflectometer (OTDR) for determining the attenuation behavior of a monomode waveguide (test waveguide) by measurement of the backscattered parts of light pulses transmitted in said waveguide. An acousto-optic modulator (AOM) which deflects the transmission beam from a laser into the waveguide to be tested at a light frequency which is modulated with the acoustic frequency when the AOM is acoustically energized in a pulse mode. The light pulses backscattered from the test waveguide are superimposed on a local oscillator beam (LO) constituted by the laser beam which traverses the AOM when the AOM is not energized. The optical system losses are reduced in that the superposition is realized in a passive coupler, particularly a fibre coupler (10, 26).

Abstract: The invention relates to a method of producing an optical cable in which at least one optical waveguide fed forward from a supply reel is provided with a loosely surrounding jacket by means of extrusion, whose length is subsequently reduced relative to the length of the optical waveguide travelling through the expander and is thereafter wound-up. The excessive length of the optical waveguide is consequently distributed uniformly along the overall length of the optical cable, because of the fact that the optical waveguides paid-out from the supply reel are stranded before they are fed into the extruder.

Abstract: An infrared detector element (20) comprises a flexible continuous film (10) of polymer material which has pyroelectric or other temperature-dependent characteristics and which is also piezoelectric so also generating microphony when it vibrates. In accordance with the invention the mounting arrangement (30,31,32) for the film (10) comprises mutually-spaced supports (32), e.g. tapered ridges (32) of a moulded-plastics substrate (30); the spacing (x) between neighboring supports (32) adjacent to the detector element (20) is sufficiently small and the tension (P) of the film (10) is sufficiently large that the natural frequency of vibration of the parts of the polymer film (10) between these neighboring supports (32) is higher than the frequency bandwidth of the detector, e.g. as determined by the highest operating frequency of a read-out circuit to which the detector element (20) is connected.

Abstract: A high pressure lamp assembly having an improved structure for supporting the discharge tube while providing an opening bi-metallic switch for electrically disconnecting the auxiliary electrode. Metallic frames are disposed at the upper and lower ends of the discharge lamp to provide at least partial support to the discharge tube. A non-conductive bridge assembly is connected between the lead through of the auxiliary electrode and a conductive rod extending from the stem. The non-conductive bridge provides at least partial mechanical support to the discharge tube. Connected across the non-conductive bridge is the starting resistor and bi-metallic switch element. When the bi-metallic element is unheated, it provides electrical connection through the starting resistor to the auxiliary electrode. When heated by the heat from the discharge tube, the bi-metallic switch moves out of engagement with the ceramic bridge and thus breaks the electrical connection to the auxiliary electrode.

Abstract: A focus control system for a camera is described having the possibilities of automatic and manual control, wherein a front lens group and a master lens group are movable. By moving the master lens group both in the automatic control mode and in one of the two manipulation ranges of the manual control mode focus control over a broad range is possible. Thereby maintaining a natured feeling for the user.

Abstract: A zoom lens is described for an electronic camera for still pictures, comprising a front group (G.sub.1), a variator group (G.sub.2) and a main group (G.sub.4). The lens is designed in such a manner that the sum of the spherical aberrations of the front group and the variator group is constant throughout the zoom range and is adapted to that of the main group.

Abstract: An optical fibre of the single-mode type in which light travels in one polarization mode is formed from a single-mode quadruple-clad fibre, in which the dimension of the light-transmitting part of the fibre in a first direction perpendicular to the axis of the fibre differs from the dimension of the light-transmitting part in a second direction perpendicular to the axis of the fibre and the first direction.

Abstract: An integrated semiconductor device including a directional optoelectronic coupler, which coupler comprises two parallel single-mode rectilinear optical waveguides over a total length D, separated by a small distance d, which coupler also comprises four electrodes of the same conductivity type, two on each waveguide, and at least one other electrode of the opposite conductivity type, characterized in that the coupler has an operation which is independent of the transverse electrical and transverse magnetic radiation components, TE and TM, respectively, present in random proportions in the incoming signal, under the condition in which the structural parameters of the coupler render it possible to ensure that the following relations are true: ##EQU1## In which relations: Z is the dimension of each electrode on the waveguides,.phi.TM and .phi.TE are the phase mismatches provoked by the refractive-index changes in the waveguides under the influence of an electric field,L.sub.CTE and L.sub.

Abstract: A device and a method of generating blue laser light having a wavelength of approximately 450 nm by means of an upconversion process, said device comprising a single semiconductor laser which emits light having a wavelength of 640 to 700 nm, and a resonator cavity which comprises a glass composition of heavy metal fluorides, which glass composition contains trivalent thulium ions. The resonator cavity preferably consists of a glass fibre having a core of a glass composition which consists of heavy-metal fluorides containing 0.01 to 1 mol% of thulium fluoride and a cladding with a lower refractive index than the core. The device suitable for generating continuous blue laser light.

Abstract: A ceramic body of a dielectric material on the basis of barium titanate comprises 0.2 to 0.5 atom % of antimony and/or cerium as the donor material. The grain size of the dielectric material is less than 2 .mu.m. The dielectric constant of the material exceeds 3500 and the material has a high electric resistance which is maintained at a high temperature and for a long period of time. The ceramic material is suitable for use in capacitors, in particular ultilayer capacitors.

Abstract: A detection device for measuring force and pressure is disclosed which includes a monomode optical fiber (1) into which polarized light is fed and, at the output of the fiber, is detected by a detection arrangement (4, 80, 81, 30, 40, 31, 41), which is sensitive to the polarization of the light. The detection arrangement is provided with means (30A, 31A) for analyzing the light according to at least two different polarization directions, forming an angle comprised between 30.degree. and 60.degree. between them. According to the invention, the device is provided with means (70, 71, 2) for feeding several non-correlated light signals, each polarized differently, into the input of the fiber, and with means (4) for distinguishing between the light signals in the said detection arrangement at the output of the fiber, which light signals have been fed into the input of the fiber. The invention is applied in intrusion detection, monitoring and security systems.

Abstract: An infrared detector array or other electrical transducer device comprising an electrically-active film (10) of polymer material is manufactured with a pattern of electrodes (11) embedded at one face of the film (10). The electrodes (11) are formed on a support (4,5) as a photolithographically defined pattern of deposited material. These electrodes (11) are then transferred to the film (10) by depositing the film material on the support (4,5) and over the electrodes (11) and removing the support (4,5) at least at the area of the electrodes (11). The polymer material of the film (10) bonds well to the electrodes (11). In this manner, fine-geometry patterns of thin electrodes (11) can be formed embedded in the face of the film (10) and having reproduceable electrode characteristics for charge detection at the film faces in piezoelectric pyroelectric and ferroelectric devices.

Abstract: In an image intensifier tube comprising a photosensitive layer an insulating wall portion is coated with a layer of chromium oxide which is deposited in the form of a chromium nitrate layer which is subsequently baked at a temperature of approximately 525.degree. C. A thin, suitably adhesive, uniform and transparent coating layer having a comparatively high resistance value is thus achieved.

Abstract: An integrated semiconductor device including at least one optoelectronic switching element, which comprises:two rectilinear monomode optical guides crossing each other at an angle 20.theta. composed of at least one heterostructure of III-V material, which comprises a substrate S of a confinement material and a guiding layer C.sub.G as well as a guiding strip RB,a p-n junction formed in the crossing region asymmetrically with respect to the bi-secting longitudinal plane of the crossing angle,characterized in that the longitudinal dimension of the p-n junction largely exceeds that of the crossing region, and in that the p-n junction is arranged so as to project symmetrically on either side of this region in this longitudinal direction.

Abstract: The invention relates to a planar optical isolator having a magneto optical gyrotropic layer and an anisotropic birefringent layer which are proportioned so that the non-reciprocal rotation of polarisation of the light (Faraday rotation) resulting from the action of a magnetic field in the forward direction of the isolator is at least substantially negatively equal to the reciprocal rotation of polarisation as a result of the birefringence, so that a TE-mode in the forward direction is guided with low damping, measures being taken for the intensive attenuation of at least one TM-mode. An isolator having a high isolating effect in which magneto optical gyrotropic layers and anisotropic birefringent layers can be connected epitaxially is obtained in that the waveguiding core layer comprises two rare earth-iron garnet (YIG) layers which are differently doped to obtain different specific birefringence.

Abstract: A tubular connector body (10) has one end (11) for receiving an optical fibre cable (1) having a plastics outer sleeve (3) protecting an optical fibre (2) and carries at the other end (12) connection means (20) for coupling to another similar connection body. A ferrule (30) is mounted within the other end (12) of the connector body (10) to support an exposed end portion (2a) of the optical fibre (2) within an irradiation settable adhesive material (40) injected into the ferrule (30). A deformable gripping member (50) is inserted into the one end (11) of the connector body (10) to grip an end portion (3a) of the plastics outer sleeve (3) of the cable upon deformation of the gripping member (50) by application of a force to the one end (11) of the tubular connector body (10).

Abstract: A read/write head particularly suitable for mapping the superconductive properties of a sample of superconducting material. The head is arranged so that the reading and writing gaps are coaxial. Although the gaps are coaxial, the reading gap and the writing gap may be optimized in length and width to provide efficient reading and writing performance. The coaxial disposition of the heads eliminates parallax error to permit detailed mapping of the properties of the surface of a sample of superconductive material.

Abstract: An angular micro-positioning system cable of readily accessing any angle within 360.degree. and thereafter precisely addressing an angular position within one ten-thousandth of a degree. The device is suitable for use in test equipment or any equipment requiring extremely precise angular positioning. The device includes a rotary motor which is mounted to a secondary frame which is pivotally mounted to a flexibly mounted main frame. The drive shaft of the rotary motor is biased in to engagement with the output wheel. A linear micro-positioner is mounted to the main frame and its drive shaft is coupled to the rotary motor frame to pivot same. The rotary motor is first rotated with the linear micro-positioner locked in place to provide coarse angle positioning. Thereafter, the drive shaft of the rotary motor is locked and the motor frame is pivoted by the linear micro-positioner which provides extremely fine angular adjustment.

Abstract: Low light level television system to detect the nocturnal light reflected from objects, comprising a main channel and acting on an extended range of wavelengths, provided with a low light level pick-up or detector tube, and a color channel, acting on a limited range of wavelengths, intended to bring forth the color for the formation of color images on a television monitor. The color channel includes an optical filter, which optical filter eliminates the infrared part of the reflected nocturnal light spectrum, a further low light level pick-up or detector tube, an electronic filter acting on the signal supplied by this further pick-up tube, the two tubes being placed side-by-side and being synchronized. The main and the color channels each act on a color channel of the monitor. The electronic filter provides a temporal integration over several fields. A processing circuit can combine the signals coming from the main and the color channels to act on a third color channel of the monitor.