A consumable cored wire for measuring a temperature of a molten steel bath includes an optical fiber and a cover laterally surrounding the optical fiber in a plurality of layers. One layer is a metal pipe, also called metal jacket or metal tube. An intermediate layer, also called filler, is arranged beneath the metal tube. The intermediate layer is a rope.

An optical fiber cable includes a core including a plurality of units which are assembled and each of which comprises a plurality of optical fibers which are assembled, a pair of tension members disposed so as to face each other with the core interposed therebetween, and a sheath covering the core and the pair of tension members collectively. The units are twisted so as to form a plurality of layers. The plurality of layers includes a first layer having first-layer units formed in an SZ-twisted shape and a second layer having second-layer units formed in an SZ-twisted shape. A twisting direction of the first-layer units is opposite to a twisting direction of the second-layer units in at least a portion in a cable length direction.

An optical cable is provided in which an optical fiber bundle with clustered or bundled optical fibers is accommodated in a tubular member and the optical fibers are formed in an excess group length (EGL) by modeling considering bending properties of the optical cable or a lossless bending radius of the optical fibers of the optical fiber bundle, thereby minimizing stress, damage or optical loss of the optical fibers in the optical fiber bundle.

An optical cable includes optical fiber units each including a bundle of optical fibers. The optical fiber units are twisted together in an S-Z configuration in which a twisting direction of the optical fiber units is reversed at a reversal part and an adjacent reversal part adjacent to the reversal part. A twisting angle, by which the optical fiber units are twisted in a circumferential direction between the reversal part and the adjacent reversal part, is 540 degrees or greater.

[Problem] The thickness on a ripcord in a circular optical cable is reduced, to improve workability. [Solution] An optical cable of the present invention includes: an optical fiber unit including optical fibers; a sheath, having a circular external form, configured to house the optical fiber unit in a housing portion; and two strength members embedded in the sheath; and two rip cords, wherein when a direction of connecting the two strength members sandwiching the housing portion is a first direction and a direction intersecting the first direction is a second direction, in a cross section of the optical cable, a cross-sectional shape of the housing portion has a dimension in the second direction greater than that in the first direction, and the two rip cords is disposed to sandwich the optical fiber unit such that a direction of connecting the two rip cords is in the second direction, in the cross section of the optical cable.

Provided is a method of manufacturing a downhole cable, the method including, forming a helical shape in an outer circumferential surface of a metal tube, the metal tube having a fiber element housed therein, and stranding a copper element in a helical space formed by the metallic tube. Also provided is a downhole cable including, a metallic tube having a helical space in an outer circumferential surface thereof, wherein the metallic tube has a fiber element housed therein, and a copper element disposed in a helical space formed by the steel tube. Double-tube and multi-tube configurations of the downhole cable are also provided.

An optical fiber unit for air-blown installations includes a plurality of optical fiber sub-units and a central member, wherein the optical fiber sub-units are stranded around the central member; wherein each of the optical fiber sub-units includes a number of optical fibers, an inner layer which is radially outer to the optical fibers, and an outer layer which is radially outer to the inner layer, wherein the outer layer includes particulate material which is partially embedded into the outer layer; and wherein the optical fiber unit further includes a binder for keeping the stranded optical fiber sub-units in a proper arrangement.

Provided is a method of manufacturing a downhole cable, the method including, forming a helical shape in an outer circumferential surface of a metal tube, the metal tube having a fiber element housed therein, and stranding a copper element in a helical space formed by the metallic tube. Also provided is a downhole cable including, a metallic tube having a helical space in an outer circumferential surface thereof, wherein the metallic tube has a fiber element housed therein, and a copper element, disposed in a helical space formed by the steel tube. Double-tube and multi-tube configurations of the downhole cable are also provided.

The invention concerns a method of SZ stranding into one strand a bundle of two or more flexible micromodules, each micromodule comprising one or more optical fibers. A first pulley is located with its winding surface adjacent to a longitudinal axis of a cabling line. The bundle of micromodules is guided over the winding surface of the first pulley, the first pulley being rotating around the longitudinal axis of the cabling line. The rotational speed, or the rotational direction of the first pulley, is alternating.

The present disclosure relates to an optical cable in which an optical fiber bundle with clustered or bundled optical fibers is accommodated in a tubular member and the optical fibers are formed in an excess group length (EGL) by modeling considering bending properties of the optical cable or a lossless bending radius of the optical fibers of the optical fiber bundle, thereby minimizing stress, damage or optical loss of the optical fibers in the optical fiber bundle.