Abstract: An optical fiber includes a core (1a) having an oblong rectangular or square cross section and made of quartz, a cladding (2) surrounding the core (1a), having a circular outer cross-sectional shape, having a lower refractive index than the core (1a), and made of resin, and a support layer (3) surrounding the cladding (2) and made of quartz.

Abstract: An optical fiber structure (10) includes an optical fiber (11a), and a block-like chip (12) joined to the optical fiber (11a). The block-like chip (12) is tapered toward its fiber-joined end.

Abstract: An optical connector structure (C) includes: an optical fiber (100) having a laser beam entrance end to which a quartz chip (120) is integrally connected; a ferrule (200) into which a portion of the optical fiber (100) including the quartz chip (120) is inserted and which holds the portion of the optical fiber; and a receptacle (21) surrounding the ferrule (200), and including a large-diameter hole (21b) formed toward an opening and a small-diameter hole formed toward a back of the receptacle so as to be connected to the large-diameter hole. A front end portion (210) of the ferrule (200) is inserted into the small-diameter hole (21a) of the receptacle (21), and a back body portion (211) of the ferrule (200) is inserted into the large-diameter hole (21b) of the receptacle (21).

Abstract: An optical fiber includes a core (1a) having an oblong rectangular or square cross section and made of quartz, and a cladding (2) surrounding the core (1a), having a circular outer cross-sectional shape, and made of resin.

Abstract: A laser guide optical fiber (100) used for transmitting a laser beam includes an optical fiber body (110) including a core (111) and a clad (112), and a quartz chip (120) integrally provided at an end surface on the light entering side of the optical fiber body (110) and including an optical waveguide portion, where at least the optical waveguide portion of the quartz chip (120) is made of pure quartz. The quartz chip (120) includes a light entering surface subjected to surface fusion treatment.

Abstract: An optical fiber structure (10) includes an optical fiber (11a), and a block-like chip (12) joined to the optical fiber (11a). The block-like chip (12) is tapered toward its fiber-joined end.

Abstract: An optical connector structure (C) includes: an optical fiber (100) having a laser beam entrance end to which a quartz chip (120) is integrally connected; a ferrule (200) into which a portion of the optical fiber (100) including the quartz chip (120) is inserted and which holds the portion of the optical fiber; and a receptacle (21) surrounding the ferrule (200), and including a large-diameter hole (21b) formed toward an opening and a small-diameter hole formed toward a back of the receptacle so as to be connected to the large-diameter hole. A front end portion (210) of the ferrule (200) is inserted into the small-diameter hole (21a) of the receptacle (21), and a back body portion (211) of the ferrule (200) is inserted into the large-diameter hole (21b) of the receptacle (21).

Abstract: An optical fiber includes a core (1a) having an oblong rectangular or square cross section and made of quartz, and a cladding (2) surrounding the core (1a), having a circular outer cross-sectional shape, and made of resin.

Abstract: A laser guide optical fiber (100) used for transmitting a laser beam includes an optical fiber body (110) including a core (111) and a clad (112), and a quartz chip (120) integrally provided at an end surface on the light entering side of the optical fiber body (110) and including an optical waveguide portion, where at least the optical waveguide portion of the quartz chip (120) is made of pure quartz. The quartz chip (120) includes a light entering surface subjected to surface fusion treatment.

Abstract: An optical fiber/glass tube fusion spliced structure includes an optical fiber made of glass and a glass tube through which the optical fiber is inserted and at least in part of the optical fiber/glass tube fusion spliced structure, an outer circumference portion of the optical fiber and an inner circumference portion of the glass tube are fusion spliced. Part of the fusion spliced portion located in one of the optical fiber and the glass tube is formed of a material having a lower fusion point than a fusion point of part of the fusion spliced portion located in the other.

Abstract: An optical fiber/glass tube fusion spliced structure includes an optical fiber made of glass and a glass tube through which the optical fiber is inserted and at least in part of the optical fiber/glass tube fusion spliced structure, an outer circumference portion of the optical fiber and an inner circumference portion of the glass tube are fusion spliced. Part of the fusion spliced portion located in one of the optical fiber and the glass tube is formed of a material having a lower fusion point than a fusion point of part of the fusion spliced portion located in the other.

Abstract: A process and apparatus for producing an elongated body changing in elastic modulus longitudinally thereof with use of polymers without resulting in variations in the outside and inside diameters of the body even when the polymers are different in extrusion characteristics or swelling characteristics. The apparatus may include a feeder 1 for extruding a first polymer in a molten state and a feeder 2 for extruding a second polymer, which is different from the first polymer in elastic modulus and similarly in a molten state. The feeders alternately discharge the respective polymers, which are continuously fed to a long-land die 5 along with a lubricant supplied from a lubricant applicator 4. The polymers are formed into the desired shape and cooled in the die 5, and thereafter extruded.