Abstract: Two optical fibres to be coupled end-to-end are respectively located within a cluster of straight rigid elements. The meeting ends of the elements are tapered to provide docking ramps which ensure precise axial alignment of the clusters.

Abstract: An electronic telephone exchange of the type employing time-space-time switching, has an optical fiber data link connecting the space and time switches. In order to meet the design requirements for use in a telephone exchange, the fiber optic link has to have fairly well defined performance parameters. In particular the overall diameter of the optical fibers employed in the optical fiber link lies between 180 and 250 microns, preferably 200 microns, and the core diameter of the optical fibers lies in the range 0.6 to 0.95 of the cladding diameter. Preferably the core diameter lies in the range 160-180 microns. The optical fiber link is characterized by the numerical aperture of the fiber, insertion loss of the fiber, sensitivity and dynamic range of detector, and the power output and extinction ratio of the transmitter.

Abstract: Optical fibers are welded together by positioning the end parts in vacuum chucks 10 and 11. Piezo-electric elements 8 force the chucks towards one another. The piezo-electric elements are put into operation by the power supply of a welding arc operating between the chucks. The heated fiber end parts are thus moved together to ensure a good welded joint.

Abstract: A communications cable comprises a single optical fibre enclosed in a sheathing assembly which protects the fibre against shock and bending. The sheathing assembly comprises end members and a protective sheath surrounded preferably by a coiled spring.

Abstract: Dielectric optical waveguides are joined using a length of tape. One end of the tape is formed into a loop and the ends of two optical waveguides to be joined inserted into opposite sides of the loop. The diameter of the loop is reduced to such an extent that the waveguides cannot be moved alongside one another. The ends of the waveguides are moved together and the loop drawn tightly around the waveguides and secured in position. The diameter of the loop can be reduced using a pair of juxtaposed rollers. The ends of the waveguides can be secured together by suitable adhesive.

Abstract: A dielectric optical waveguide joint in which first and second dielectric optical waveguides are located end to end in a groove in a plate of non-ductile material. The dielectric optical waveguides are retained in the groove by a mass of ductile material which has been formed so as to flow into intimate contact with the plate and the first and second waveguides. The invention also provides a method of forming a waveguide joint.