Abstract: Amono-coated optical fiber that has a bending loss characteristic in which an optical loss increase at a bending radius 13 mm is 0.2 dB/10 turn or less, an optical fiber ribbon that includes two-dimensionally disposed resin portions for bonding the adjacent 2-fiber mono-coated optical fibers in plural places, the resin portions being disposed apart from each other in the longitudinal direction of the optical fiber ribbon and an optical fiber cable that includes a cable core portion that stores twisting of plural units where the mono-coated optical fibers constituting the optical fiber ribbon are collected.

Abstract: Amono-coated optical fiber that has a bending loss characteristic in which an optical loss increase at a bending radius 13 mm is 0.2 dB/10 turn or less, an optical fiber ribbon that includes two-dimensionally disposed resin portions for bonding the adjacent 2-fiber mono-coated optical fibers in plural places, the resin portions being disposed apart from each other in the longitudinal direction of the optical fiber ribbon and an optical fiber cable that includes a cable core portion that stores twisting of plural units where the mono-coated optical fibers constituting the optical fiber ribbon are collected.

Abstract: As the endface preparation of the coated optical fiber, cutting using thermal stress is carried out, and a ceramic heater is used as a heat source, thereby making it possible to provide a coated optical fiber endface preparation method and tool capable of increasing the cutting success rate of the coated optical fiber. The coated optical fiber is removed of its coating to obtain the bare optical fiber. The bare optical fiber is heated by the heat source consisting of the ceramic heater, and is cut by further adding stress to part of the bare optical fiber which has been provided with the thermal stress. When heating the bare optical fiber, the product of a temperature and the heating time of the heat source is made 3000° C. sec or more.

Abstract: A single mode fiber is provided which is suitable for high-speed, large-capacity optical communication and for optical wiring. The single mode fiber has a first cladding region with a uniform refractive index, a core region with a refractive index higher than that of the first cladding region, and a second cladding region including at least four air hole regions placed in the first cladding region. Optimization can be achieved by making the distance from the center of the core region to the air hole regions equal to 2–4.5 times the core radius, and the air hole radius equal to or greater than 0.2 times the core radius. It is preferable the core radius be 3.7–4.8 ?m, the relative index difference of the core region from the first cladding region be 0.3–0.55 %.

Abstract: A single mode fiber is provided which is suitable for high-speed, large-capacity optical communication and for optical wiring. The single mode fiber has a first cladding region with a uniform refractive index, a core region with a refractive index higher than that of the first cladding region, and a second cladding region including at least four air hole regions placed in the first cladding region. Optimization can be achieved by making the distance from the center of the core region to the air hole regions equal to 2-4.5 times the core radius, and the air hole radius equal to or greater than 0.2 times the core radius. It is preferable the core radius be 3.2-4.8 ?m, the relative index difference of the core region from the first cladding region be 0.3-0.55%.

Abstract: The present invention's optical cable is provided with optical fibers, a forming pipe for housing the optical fibers, a sheath provided around the forming pipe, and at least one pair of rip cords embedded in the sheath. The forming pipe is formed of a plurality of tapes so that it is dividable along its longitudinal direction. When dividing the optical cable, the rip cords are pulled to tear open the sheath, and the already split forming pipe is divided while staying adhered to the respective parts of the sheath. As a result, the division of the sheath and the forming pipe is carried out in one stroke, so that the optical fibers inside the forming pipe can be exposed easily and quickly.

Abstract: A cable and a cable stripping method which facilities the stripping of an intermediate part of a cable having a cable core covered by a plastic sheath provided around the outer periphery without damaging the cable core. In a cable having a plastic sheath 2 on a cable core 1, either a groove 2a is provided in the inner surface of the plastic sheath 2 extending in the longitudinal direction of the cable. A ripcord 3 is either fitted in the groove 2a or adhered to the inner surface of the plastic sheath. In either case, the position-indicating means 2b showing the position of the ripcord is provided on the outer surface of the plastic sheath 2 at the point where the ripcord 3 is fitted.

Abstract: The present invention's optical cable is provided with optical fibers, a forming pipe for housing the optical fibers, a sheath provided around the forming pipe, and at least one pair of rip cords embedded in the sheath. The forming pipe is formed of a plurality of tapes so that it is dividable along its longitudinal direction. When dividing the optical cable, the rip cords are pulled to tear open the sheath, and the already split forming pipe is divided while staying adhered to the respective parts of the sheath. As a result, the division of the sheath and the forming pipe is carried out in one stroke, so that the optical fibers inside the forming pipe can be exposed easily and quickly.

Abstract: A cable and a cable stripping method which facilitates the stripping of an intermediate part of a cable comprising a cable core covered by a plastic sheath provided around the outer periphery without damaging the cable core. In a cable having a plastic sheath 2 on a cable core 1, either a groove 2a is provided in the inner surface of the plastic sheath 2 extending in the longitudinal direction of the cable and a ripcord 3 is fitted in the groove 2a or a ripcord 3 is adhered to the inner surface of the plastic sheath, and in either case the position-indicating means 2b showing the position of the ripcord is provided on the outer surface of the plastic sheath 2 at the point where the ripcord 3 is fitted.

Abstract: The invention is directed to an optical connector in which a length of an optical fiber 5 projects from a connection end surface (16) of a ferrule (1) is accurately set, a method of and a fixture for setting the projection length of the optical fiber. A recess surface (33) is formed in a ferrule receiving surface (32). A depth of the recess surface (33) is equal to a length an optical fiber (5) projects from the connection end surface (16) of the ferrule (1). The ferrule (1) is held by ferrule holding members (35a) and (35b), so that the ferrule (1) is abutted against the ferrule receiving surface (32) by the urging force of compression springs (36). Through the ferrule (1), an optical fiber cored line (3) is projected from the connection end surface (16) of the ferrule (1) and abutted against the recess surface (33).

Abstract: The invention is directed to an optical connector in which a length of an optical fiber 5 projects from a connection end surface (16) of a ferrule (1) is accurately set, a method of and a fixture for setting the projection length of the optical fiber. A recess surface (33) is formed in a ferrule receiving surface (32). A depth of the recess surface (33) is equal to a length an optical fiber (5) projects from the connection end surface (16) of the ferrule (1). The ferrule (1) is held by ferrule holding members (35a) and (35b), so that the ferrule (1) is abutted against the ferrule receiving surface (32) by the urging force of compression springs (36). Through the ferrule (1), an optical fiber cored line (3) is projected from the connection end surface (16) of the ferrule (1) and abutted against the recess surface (33).

Abstract: A short optical fiber 2 is incorporated in a ferrule 1 having a polished front end, so as to be projected from the rear end of the ferrule. In a base member 3 in which the short optical fiber is to be fitted into a hole 3b, a V-groove 3d to which the glass portion of an optical fiber is to be fixed, and a V-groove 3e to which the coated portion is to be fixed are formed. A cover member 4 is placed on the base member. The base member 3 and the cover member 4 are clamped by clamp members 5a and 5b and the base member 3 presses to V-grooves. Wedges which are not shown are pressingly inserted between recessed 3g and 4c, and 3h and 4d, and an optical fiber 10 is inserted from the rear portion. Thereafter, the wedges are detached and the optical connector is attached to the terminal of the optical fiber 10.

Abstract: An optical connector is provided where an biasing device 26 which biases a ferrule 24 having an optical fiber 22 secured thereinside and a tip end face 23 which has been polished, in a tip end face 23 direction, is located to the rear of a connection mechanism 25 for connecting the optical fiber 22 on the ferrule 24 side and a separately inserted optical fiber 22a, at a rear end side of the ferrule 24 opposite to the front end face 23. The connection mechanism 25 has a construction which uses a mechanical splice, and is opened and closed by a release member inserted into an insertion opening 39 which is opened along an alignment axis direction. Hence the opening and closing operation does not interfere with the biasing device 26, so that operability is improved. Moreover, for this type optical connector there is provided an optical connector housing 21 which accommodates the ferrule.

Abstract: A spacer having a high-tensile member at the center thereof has grooves extending helically. Coated optical fibers have been disposed in each groove. This assembly is covered with a wound covering and further with a sheath. The proportion of the total sectional area of the coated optical fibers to the sectional area of each groove, i.e., the degree of packing, is regulated to 10 to 50%.

Abstract: The invention is directed to an optical connector in which a length of an optical fiber 5 projects from a connection end surface (16) of a ferrule (1) is accurately set, a method of and a fixture for setting the projection length of the optical fiber. A recess surface (33) is formed in a ferrule receiving surface (32). A depth of the recess surface (33) is equal to a length an optical fiber (5) projects from the connection end surface (16) of the ferrule (1). The ferrule (1) is held by ferrule holding members (35a) and (35b), so that the ferrule (1) is abutted against the ferrule receiving surface (32) by the urging force of compression springs (36). Through the ferrule (1), an optical fiber cored line (3) is projected from the connection end surface (16) of the ferrule (1) and abutted against the recess surface (33).

Abstract: A short optical fiber 2 is incorporated in a ferrule 1 having a polished front end, so as to be projected from the rear end of the ferrule. In a base member 3 in which the short optical fiber is to be fitted into a hole 3b, a V-groove 3d to which the glass portion of an optical fiber is to be fixed, and a V-groove 3e to which the coated portion is to be fixed are formed. A cover member 4 is placed on the base member. The base member 3 and the cover member 4 are clamped by clamp members 5a and 5b and the base member 3 presses the V-grooves. Wedges which are not shown are pressingly inserted between recesses 3g and 4c, and 3h and 4d, and an optical fiber 10 is inserted from the rear portion. Thereafter, the wedges are detached and the optical connector is attached to the terminal of the optical fiber 10.

Abstract: An optical drop cable-units cable comprising a plastic pipe and a plurality of strandless optical drop cable-units and held in the plastics pipe, in which a space factor(B.times.n/A).times.100(%).ltoreq.51%whereA: void cross-sectional area of the plastic pipe,B: a cross-sectional area of a single optical drop cable-unit, andn: number of optical drop cable-units.

Abstract: An optical fiber path joint member according to the present invention includes a main path having an inlet and an outlet at respective ends thereof; and at least one joint path joining to the main path in one direction at an angle of equal to or less than 45.degree.. A method of blowing an optical fiber is comprised of the step of blowing an optical fiber into a pipe through the optical fiber path joint member according to the present invention.

Abstract: A tube sheet is formed by integrating a plurality of tubes into the form of a sheet. The tube sheet is constricted in junction portions of the respective tubes so that the tube sheet is deformed in these junction portions. At least one such tube sheet is disposed around a center member to form a tube-aggregated cable.

Abstract: In an optical cable according to the present invention, a grooved spacer has a plurality of grooves in its circumference, and the cutting direction of the grooves is inverted at predetermined periods. Optical fibers are received in the respective grooves. On the circumference of the grooved spacer, a linear member is provided around the grooved spacer along the longitudinal direction of the optical cable at a predetermined period. The linear member is fixed to the grooved spacer by welding or bonding in the portions where they touch the outer circumferences of the grooved spacer so as to restrain the optical fibers. The linear member restraining the optical fiber to be taken out are cut in positions above the groove in which the optical fiber is received so that the required optical fiber can be taken out.