Abstract: A sensor (1) for sensing the magnitude of current flowing in a conductor (12) based upon the Faraday effect. The sensor (10) includes a light source (14) for emitting a beam of light which is transmitted through the magneto-optic material (28) with one or more layers which causes a rotation of the plane of polarization of the light beam in proportion to the current flowing in the conductor (12). The beam of light with the rotated plane of polarization is split by a beam splitter (38) into two components which are then processed to produce an outputs (62, 63) indicative of the AC and DC components of the current flowing in the conductor. The outputs (62, 63) produced are independent of system losses.

Abstract: A sensor (10) for sensing the magnitude of current flowing in a conductor (12) based upon the Faraday effect is disclosed. The invention utilizes a magneto-optic material having one or more layers (32) in which alignment with an optical fiber is not critical in achieving accurate current measurements. A magneto-optic material (28) in accordance with the invention includes one or more layers (32) each having a substrate having opposed surfaces coated with a material exhibiting the Faraday effect in which light from a light source is transmitted through the magneto-optic element without substantial internal reflection and is incident upon a surface area of the coating which is greater than the surface area of the beam of light.

Abstract: Encapsulated optical fibres (FIG. 1A), for e.g. a submarine cable have their encapsulation removed by high velocity hot air blowers (6,7), leave free the acrylate coated fibres for splicing/jointing. An automated equipment moves the blowers progressively along the fibres to free between 0.75 and two meters.

Abstract: The strength members of the optical fibre cables to be jointed comprise inner and outer layers of high-tensile wires (9, 10; 9', 10') arranged on respective pressure-resistant tubes (5; 5'), each containing an optical fibre package (not shown). The strength members are jointed by trapping the wires between a quill (15) and a ferrule (16) pressed towards the quill. The quill (15) is of a relatively hard steel and serves to partially reinstate the pressure tube between the ends of the cables, whereas the ferrule (16) is of a relatively soft steel. For jointing of two dielectric covered elements the ferrule is subsequently encapsulated in a dielectric moulding (27). A thin-walled reinstatement tube (17) is arranged between the quill (15) and one tube (5'). The cavity in the reinstatement tube (17) is larger in diameter than the cavity in the tubes (5 and 5').

Abstract: The primary coating (2) of an optical fibre element is reinstated over a fused joint between two silica fibre elements (3) by a casting process. The jointed silica fibre elements are arranged in a groove (8) of a mould (9, 10, 11) and liquid uncured primary coating material placed into the groove, the groove ends being blocked by the existing primary coatings (2) on the fibre elements (3). The coating material in the groove is cured by, for example, heating the mould. Secondary coating material (1) may be injection moulded using a two-part mould to reinstate the secondary coating over the cast primary coating.