Abstract: In order to expand the product between the transmission length and the transmission bandwidth of an optical fiber for use in the optical communication and to facilitate the connection between the optical fibers, the optical fiber is made of transparent materials of three concentric layers of a core whose refractive index gradually decreases in the radial direction from the center, an intermediate layer which has a uniform refractive index lower than the varying refractive index of the core, and a cladding which has a uniform refractive index substantially equal to the lowest refractive index of the core.

Abstract: A four port apparatus is described for multimode electro-optic switching with reduced voltages relative to that required by the prior art. Two optical waveguides formed on an electro-optic substrate are in parallel relationship for a predetermined length to establish a coupling region, throughout which they are separated by a barrier having an index of refraction formed by, that is, lower than the index of refraction of the optical waveguides. Electrodes extending over the length and thickness of the barrier are deposited on both sides of the electro-optic crystal to which voltages may be applied to provide optical coupling or relatively high optical isolation between the two optical waveguides.

Abstract: An optical fiber connector in which each fiber is terminated by a coupling element comprising a cylindrical transparent body having a concave reflector on one end facing into the body and a circular reflector on the opposite end facing the concave reflector. The circular reflector has a diameter less than that of the cylindrical body and is concentric therewith. This arrangement has the advantage that the main focussing elements are reflectors and therefore require far less curvature than lenses.

Abstract: An optical fiber coupling element in which a short length of optical fiber is placed in a glass sleeve with one end of the fiber projecting from the sleeve. The glass sleeve is collapsed onto the fiber, and a watch jewel is fitted over the fiber end. The other end of the sleeve is flared to facilitate the insertion into it of a second fiber. The sleeve and jewel are sealed into one end of a ferrule.

Abstract: In order to make the transmission loss of the lowest order leaky mode over the transmission length 10dB or more, an optical fiber for optical transmission is constructed of a cladding layer whose refractive index is constant, an intermediate layer which has a constant refractive index lower than the refractive index of the cladding layer, and a core whose refractive index is continuously varied so as to be the highest at the central part and to be substantially equal to that of the cladding layer at the peripheral part, and the thickness of the intermediate layer is 0.1-1 times the radius of the core.

Abstract: A brancher-mixer for optical fibres bundles enabling the luminous energy emanating from a transmitting bundle to be divided between two receiving bundles and essentially consisting of two monofibres laterally coupled at one of their ends to divide the luminous flux emanating from the transmitting bundle. The two monofibres are arranged in a common casing provided with mechanical connections to establish the optical connections to the three bundles of fibres.

Abstract: A coupler is disclosed for properly positioning the endface of an optical waveguide filament with respect to an optoelectronic device in a repeatable fashion. Three elongated rods of deformable material are disposed in mutually contacting relationship within a bore which terminates at the device. After a filament is inserted into the aperture between the rods so that its endface is disposed adjacent to the device, an elastomeric washer is caused to deform inwardly against the rods, thereby causing them to engage the filament. Since the ends of the rods adjacent to the device are secured in the bore, the filament may be replaced by other filaments, the endfaces of which will be precisely positioned with respect to the optoelectronic device.

Abstract: An optical waveguide coupling comprises a connector having a longitudinal bore and a pair of optical waveguides, for example, optical fibres, whose ends are disposed in opposite ends of the longitudinal bore with the waveguide ends optically coupled to one another. The connector comprises a generally tubular body and a multiplicity of flexible elongate members mounted on the tubular body and extending longitudinally therethrough to define the longitudinal bore, the elongate members being spaced apart around the tubular body and being individually displaceable towards the tubular body. The flexible elongate members are displaced towards the tubular body by the ends of the optical waveguides and resiliently engage the ends of the optical waveguides to maintain them in alignment with one another.

Abstract: Method for connecting two groups of optical fibres provided with a sheath or protection coating and connector for effecting this method. The unstripped optical fibres of each group are located in longitudinal grooves in a support piece of a respective connector, with the ends of the fibres extending beyond the end of each support piece; the optical fibres are retained in the grooves in each support piece; the ends of the fibres extending beyond each support piece are stripped; the optical fibres are slided in said grooves into a position where parts of the stripped ends occupy respective parts of the grooves; the unstripped and stripped portions of the optical fibres are locked in this position; the end plane of each support-fibre assembly is polished and the two connectors are joined together.

Abstract: An amorphous film of As.sub.2 S.sub.5 on a substrate is disclosed for use in various optical applications. The film can be shaped as a lens to focus light. By mounting an acoustic transducer on the film to produce surface or bulk acoustic waves light moving in the film can be deflected or modulated respectively. The film can also be used in anti-reflective, high reflectivity, and photoconductive coatings.

Abstract: A terminal for an optical waveguide includes a connector having a longitudinal bore in which an end of an optical waveguide is to be anchored, lens means for transmitting light from one end of the waveguide and defining a recess including a focal point of the lens means, and a housing in which the connector and lens means are mounted. The terminal also includes an elongate optical member having first and second ends with respective end faces, the first end of the elongate optical member extending partially through the connector and being anchored therein, and the second end of the elongate optical member being mounted in the recess in the lens means with its end face disposed at the focal point of the lens means. The connector includes means for maintaining the first end of the optical member and an end of an optical waveguide in alignment with one another.

Abstract: A multiple connector for releasably connecting a plurality of pairs of optical fibres having two connector members, one having an axially moveable member therein with a plurality of axial holes, the other member having a plurality of aligning members extending axially. When assembled, an aligning member is aligned with an axial hole. The aligning member has a central bore portion a close fit on an uncoated fibre and tapered bores leading into the central bore portion. The axially moveable member is resiliently biased to project from a front face of the related connector member. On assembly the axially moveable member is pushed back into the connector member to expose one set of fibre ends which enter the aligning members. The other set of fibre ends are initially positioned in the aligning members. Preferably holding members are attached to the fibres and inserted from the rear of each connector member. This permits rear insertion of fibres.

Abstract: An exposure meter for use in photography which includes means for measuring brightness at a plurality of places in a scene to be measured for exposure, means for calculating frequency distribution of the brightness which divides brightness value into many stages and counts frequency of occurrence of brightness at each of the stages, and means for calculating, under designated conditions, position whereat film latitude is to be present within the width of the brightness distribution.

Abstract: An optical coupler system having two optical elements mounted adjacent one another with mutually confronting surfaces, and an optically clear elastomer interposed therebetween in abutment with the confronting surfaces. A method of assembling an optical coupler system is also disclosed comprising the steps of providing an optically clear elastomer, positioning an end of an optical fiber adjacent the elastomer, pressing the optical fiber end against the elastomer to form an elastomer surface depression from which the optical fiber projects, and holding the optical fiber end in place in pressure contact against the elastomer within the elastomer surface depression.

Abstract: A light smoothing device for rendering a non uniform distribution of light more uniform especially suited for use in line scanning in combination with a light conducting rod which transmits light incident on its surface to its end faces for subsequent detection. The smoothing device has an optical passage with a reflecting interior surface an inlet to the passage and a detector at the other end of the passage. The passage ensures at least part of the light entering the inlet is reflected prior to incidence on the detector.A number of forms of optical passage are disclosed having various reflecting segments of convex, plain or concave curvature.

Abstract: A scanning accessory for a microscope/photometer, where the photometer system is mounted to or inside an intermediate tube of the microscope and the intermediate tube is provided near or at the one end of its lower side with a coupling system for mounting to the stand and at the opposite side with a coupling system for mounting the ocular, the photometer being inserted into the intermediate tube's beam by means of a beam splitter, a subsequent triple mirror and an ocular. The scanning accessory preferably periodically changes the relative position of the transmitted beam (4a) and of the image (76a) or (76b) of the measuring stop (42) with respect to the microscope image (72) and is located between the photometer system (41-46) and the beam splitter (22) mounted inside the intermediate tube (2) of the microscope for the purpose of enlarging the application possibilities of the microscope/photometer.

Abstract: A mass of dimensionally unstable material in cylindrical form is radially shrunk and confined within an outer sleeve of dimensionally stable material. Two ends of optic waveguides are inserted into a bore provided axially through the unstable material. Upon causing the unstable material to expand radially, the presence of the outer sleeve forces the unstable material to compress and grip radially upon the waveguides, thereby urging them into colinear alignment.

Abstract: A radiometer on an orbiting spacecraft derives high spatial resolution information from terrestrial and atmospheric regions. N elements or subapertures on the spacecraft transduce electromagnetic energy into electric signals.Many or all of the elements are simultaneously illuminated by electromagnetic energy radiated from the same region. Identical, parallel processing channels are responsive to the N elements. Each of the channels includes a variable gain amplifier responsive to the signal transduced by its corresponding array elements. The gain of each amplifier is controlled as a function of the output difference when the channel is connected periodically to each of a pair of Dicke noise sources, such as resistors maintained at predetermined temperatures.

Abstract: An apparatus for measuring scalar irradiance or the incident flux of radiant energy from a 4.pi. solid angle about a point. The present invention relates to an apparatus which comprises a solid spherical radiant energy collector, a radiant energy detector which converts radiant energy into electrical signal, a light conductor which transmits a portion of the radiant energy within the spherical collector to the detector, a means for conditioning the electrical signal such that the electrical signal responds to the intensity of the incident flux, and a means for displaying the conditioned signal. The apparatus further includes a spectral shaping assembly located intermediate the detector and the light conductor whereby the spectral characteristics of the radiant energy are adjusted to compensate for apparatus response in the desired spectral region.

Abstract: An optical ribbon or flat cable comprised of a plurality of elongated optically transmissive elements arranged parallel to one another and enveloped within a soft cast synthetic resin, such as an isocyanate, an epoxide, an unsaturated polyester, a silicone, an ethylene derivative, etc., which is chemically hardened or cured about the optical elements at a relatively low temperature.