Abstract: An economical Cds photoresistor is connected to the input of an operational amplifier. Logging diodes are connected in a feedback configuration with the operational amplifier through a galvanometer meter. The log of the ratio of the input currents to the operational amplifier is independent of supply voltage thereby permitting the use of a wide tolerance battery supply. The input of the operational amplifier and the meter are referenced to a voltage divider. A feedback connection regulates meter current independently of meter resistance that varies strongly with ambient temperature changes. Light-emitting diodes provide regulation against battery voltage variation, light for meter scale illumination, and an inherent, unfailingly diagnostic battery-check response.

Abstract: A three-layer structure optical fiber comprises a first transparent dielectric core layer having a relatively high refractive index, a second transparent dielectric intermediate layer having a relatively low refractive index and a third transparent dielectric cladding layer having an intermediate refractive index wherein the parameter of the optical fiber is determined as follows: ##EQU1## where B is the bandwidth of the signal to be transmitted, z is the transmission distance, C is the velocity of light in vacuum, .eta.o is the refractive index of the core layer, q is the ratio of refractive indices between the core layer and second layer, V = normalized frequency, ##EQU2## p is the ratio of refractive index between the core layer and the third layer, and U.sub.11 =2,405.

Abstract: A connector and coupling assembly to couple a single pair of optical fibers provides for securing the respective fibers in identical metallic connector pins and inserting these pins in an alignment sleeve having a precision axial aperture which maintains proper alignment of the pins and the fibers carried thereby. The respective connector pins are carried by coupling members which resiliently hold the pins so as to allow alignment thereof by the alignment sleeve while the coupling members provide for axial clamping of the pins together in axial alignment.

Abstract: Optical fibres and optical cables of improved bandwidth, especially intended for use in a communications system. Over-compensated and under-compensated fibres or cable sections are connected alternately so that each fibre or cable section tends to correct the modal dispersion originating in the previous fibre or cable section, giving a narrower overall impulse response and hence a better bandwidth. This arrangement also substantially reduces the variation of bandwidth with source wavelength.

Abstract: In a graded index optical fiber whose refractive index distribution (n) at the radial length r is given by ##EQU1## where (n.sub.0) is the refractive index at the core axis, (a) is the core radius, .alpha. is a power exponent, n.sub.e is the refractive index of the cladding, and .DELTA.=(n.sub.0 -n.sub.e)/n.sub.0, said exponent .alpha. and the normalized frequency v (=(2.pi.an.sub.0 /.lambda.).sqroot.2.DELTA., .lambda. is the wavelength) are determined so that the group delay of the fundamental mode is equal to that of the first higher order mode. In particular, the value of .alpha. is determined in the range 3.2.ltoreq..alpha..ltoreq.6.0. Thus, the optical fiber with both a broad bandwidth and a large core diameter can be provided. A large core diameter optical fiber facilitates the connection or the splicing of two optical fibers.

Abstract: A switch for optically connecting a first light conducting fiber selectively with at least one second light conducting fiber characterized by a first light conducting fiber having a magnetic sleeve adjacent the free end thereof, at least one second light conducting fiber, a substrate having a first flat surface with a layer being disposed on the first flat surface and having a recess with a groove for each of the first and second fibers extending therefrom. Each of the second fibers is disposed in its respective groove with the free end extending into the recess and the first fiber is disposed in its groove with its free end which has the magnetic sleeve being mobile in the recess between a first position forming an optical connection with one of the second fibers and a second position out of optical connection with one of the second fibers so that an application of an external magnetic field causes the free end of the first fiber to move between the first and second positions.

Abstract: Connector for simultaneous end-to-end connection of groups of seven optical fibres. The ends of the groups of fibres to be connected are brought into mutual radial contact in a centered hexagonal configuration, e.g. by a guide structure (8) and associated clamping device (9), and their end faces of two groups are then brought into contact with each other. Particularly intended for on site connections of optical cables.

Abstract: The meter senses flashes of illumination, it converts the illumination to an electrical current whose magnitude is proportional to the intensity of the illumination; it integrates the current over a period of time corresponding to a selected shutter speed by charging a capacitor; it discharges the capacitor and measures the time required to do so; it converts the time required to discharge the capacitor into a corresponding signal representative of an appropriate camera aperture setting for a preselected film sensitivity and shutter speed via a microprocessor and a stored data program; and then displays the camera aperture setting on a multi-segment display. This process is repeated with each new flash of illumination automatically. The meter also measures multiple flashes and displays an accumulated camera aperture setting as well as the number of flashes needed to accumulate that setting.

Abstract: A light signal entering a photo-electric converter means is interrupted at a certain interval of time. An electrical signal produced from the photo-electric converter means, after a predetermined amount of electrical signal is added to it, is A-D converted. The difference between the digital signal associated with the interruption of light to the photo-electric converter means and the digital signal associated with non-interruption of light to the photo-electric converter means is produced, which difference is proportional to the incident light signal. Even when the light entering the photo-electric converter means is very weak, the fact that a predetermined amount of electrical signal is added contributes to A-D conversion of good linearity. Even very weak light is thus A-D converted accurately. Noises and undesirable DC signal components contained in the two types of digital signals are offset by production of the difference.

Abstract: A connector for coupling a pair of single optical fibers is disclosed. The connector comprises a base plate having a V-groove in its upper surface having a transverse cross-section of an equilateral triangle. Two sets of three equal diameter cylindrical rods lay in the groove each defining an interstitial space therebetween which receives an optical fiber. The sets of rods have mating end faces which abut each other in the groove. A compression plate is mounted over the base plate to arrange the rods in the V-groove so that the centers of the rods are disposed at the vertices of the same equilateral triangle so that the fibers in the interstitial spaces between the rods will become precisely laterally aligned. The groove in the base plate may contain a larger number of rods for aligning a plurality of optical fibers within the interstices defined by the rods. The groove may also have the configuration of a truncated equilateral triangle. A flat cable single optical fiber connector is also disclosed.

Abstract: A short length of step index fibre is placed in front of graded index fibre. Walls of the step index fibre form multiple images of its entrance face which are imaged by the graded index fibre to give a more nearly uniform illumination of the graded index fibre and thereby avoid the variable loss properties which can result from the repetitive focusing produced by point illumination or well collimated illumination.

Abstract: A portable device for coupling optical fibers consisting of an insulative block so designed as to allow a number of optical fibers to come together, a piezoelectric generating means secured to the block and connected to the piezoelectric generator so that optical fibers will be brought together at a point between the electrodes. Electricity generated causes an arc across the electrodes which generates sufficient heat to join the optical fibers.

Abstract: An optical cable is constructed using a core of high tensile strength steel wires around which is disposed a radial system of chambers in the form of a helix retaining the optical conductors so that they are movable radially thereby protecting the optical conductors from tensile, compression and flexural stresses.

Abstract: A clad light-conducting fiber comprising a core, a cladding of lower refractive index than the core, fused to the core, and a plurality of spots of inhomogeneity such as bubbles wholly within the core, spaced along the length of the light-conducting fiber. These light-conducting, bubble-containing fibers are used in a decorative structure comprising a light source and a suitably mounted group of light-conducting, bubble-containing fibers wherein the light is transmitted into and thereafter through the group of fibers, showing decorative points of light along the length of the fibers as well as at their ends.

Abstract: The jacket of a cored light guide is completely or partially etched away; or, if the light guide is a gradient fiber guide, it is etched to about the light guiding diameter. A lens is then adhered to the end of the fiber, the lens being made of a material having a melting point which is low in relation to the melting point of the core material, to result in a light guide having an essentially semispherical lens at the end; adhesion may be effected by melting on a lens of lower melting point glass, or by making the lens of transparent epoxy, a drop of which can be cured on the light guide to form the lens.

Abstract: A guide member and an assembly of a guide member and connector for making an optical signal transmissive connection between the ends of a pair of single optic fibers and the method of making the guide member. The guide member is in the form of at least three predetermined length glass rods disposed in a side-by-side array and connected together along peripheral portions to form a smooth, cusp-shaped interstitial channel therebetween. The ends of the guide member's channel are open and preferably are of greater cross-sectional area than the intermediate portion of the channel to facilitate entry of an optic fiber into the channel. The guide member is disposed within a cavity in the connector. The connector is formed of a pair of mating connector members. Each member includes a first and second end with a passageway extending longitudinally therebetween and through which a respective fiber passes entering the guide member.

Abstract: A fiber optic termination is disclosed in which an optical fiber is inserted into a ferrule having an annular groove formed in the wall of the bore passing through the ferrule adjacent to the forward mating end thereof. The forward end of the fiber is located in the bore adjacent to the groove and is heated in situ to form an enlarged spherical lens on the end of the fiber. The periphery of the lens extends into the groove to retain the fiber in the ferrule without the use of an adhesive.

Abstract: An improved connector pin assembly and method for concentrically aligning and terminating an optical fiber of a fiber optic cable with respect to the outer dimension of the pin negates the heretofore required epoxy or other adhesive for providing secure termination of an optical fiber within a terminal pin. The assembly includes a terminal pin having a fiber optic cable receiving bore extending into the pin from its rear end and a terminal end bore of smaller dimension extending into the terminal pin from the terminal pin forward terminating end. The terminal end bore communicates with the cable receiving bore and is concentric to the outer dimension of the terminating pin terminal end. A resilient insert member having a central aperture dimensioned for receiving the optical fiber and an outer portion which is greater in dimension than the terminal end bore when the insert member is in its free uncompressed state is forced into the terminal end bore.

Abstract: ZnCl.sub.2 optical fibers are advantageously used for transmission of radiation in the infrared portion of the spectrum. Losses as low as 10.sup.-3 dB/km may be obtained when radiation of wavelength between 3.0 and 4.5 microns is transmitted in such fibers. Fabrication techniques allow for the formation of graded fibers to further improve transmission characteristics.

Abstract: The disclosure relates to a method and apparatus for connecting optical waveguides in coincident alignment, and features a connector divided into intermating sections, with each section having a fixture portion which is connected to an optical cable to provide a datum plane for precise waveguide positioning, and with each connector section further including a waveguide supporting portion in the form of an open box configuration latchingly receiving a corresponding fixture portion therein; and the open box configuration being provided with a projecting tongue portion provided with a pad of compliant material which laterally supports each waveguide in a corresponding fixture portion, the compliant material intimately encircling the waveguides upon intermating the connector sections and the compliant material further undergoing elastomeric deformation yieldably encircling the waveguides to align the waveguide central axes colinearally or coincidentally.