Abstract: A laser light source includes a light source section for outputting pulse laser light ?1, ?2 with a mutually identical repetition frequency, an optical amplification section for amplifying and outputting the pulse laser light ?1, ?2 output from the above light source section by means of a common optical amplification medium, an optical demultiplexing section for mutually demultiplexing pulse laser light ?1, ?2, an optical multiplexing section for multiplexing and outputting the pulse laser light ?1, ?2 demultiplexed in the above optical demultiplexing section, and an optical path length difference setting section for adjusting an optical path length difference between the pulse laser light ?1, ?2 in between the optical demultiplexing section and the optical multiplexing section.

Abstract: The present invention provides fluorescent glass containing at least 50 mol % of at least one kind of oxide selected from the group consisting of SiO2, GeO2, and P2O5 as a glass constituent of a region containing a Bi ion as a dopant.

Abstract: A laser light source includes a light source section for outputting pulse laser light ?1, ?2 with a mutually identical repetition frequency, an optical amplification section for amplifying and outputting the pulse laser light ?1, ?2 output from the above light source section by means of a common optical amplification medium, an optical demultiplexing section for mutually demultiplexing pulse laser light ?1, ?2, an optical multiplexing section for multiplexing and outputting the pulse laser light ?1, ?2 demultiplexed in the above optical demultiplexing section, and an optical path length difference setting section for adjusting an optical path length difference between the pulse laser light ?1, ?2 in between the optical demultiplexing section and the optical multiplexing section.

Abstract: Based on an intermediate 20A in which a cladding portion 22 is formed on the outer periphery of a core portion 21, a pair of holes 23 and 24 are provided parallel to the z axis on both sides of the core portion 21 within the cladding portion 22, and an intermediate 20 is thereby fabricated. In this intermediate 20, a width Ry in the y-axis direction is made smaller than a width Rx in the x-axis direction. Moreover, a cylindrical stress applying part 33 is inserted into a hole 23 of the intermediate 20, and a cylindrical stress applying part 34 is inserted into a hole 24 thereof. Thus, a preform 40 is formed. These materials are drawn and integrated together, and a polarization maintaining optical fiber is thereby manufactured.

Abstract: A drawing apparatus 1 comprises a drawing furnace 11, a protecting tube 21, and a resin curing unit 31. A buffer chamber 41 is disposed between the drawing furnace 11 and the protecting tube 21, and has a length L1 in the drawing direction of the optical fiber 3. The buffer chamber 41 is constituted by a first buffer cell 42 and a second buffer cell 45. In the space within the buffer chamber 41, an He gas, which is an atmosphere gas within the drawing furnace 11, and the air, which is an atmosphere gas within the protecting tube 21, exist in a mixed state. The optical fiber 3 drawn upon heating in the drawing furnace 11 is fed to the protecting tube 21, and a predetermined part of the optical fiber 3 is annealed at a predetermined cooling rate. Thereafter, a coating die 62 coats the optical fiber 3 with a UV resin solution 63, and the resin curing unit 31 cures the UV resin 63, whereby a coated optical fiber 4 is obtained.

Abstract: The drawing method of the present invention uses a drawing furnace comprising a furnace muffle tube, a furnace body and a heater. According to the method, an optical fiber preform is inserted from the inlet of the furnace muffle tube, the optical fiber preform is melted by means of a heater, under a specified gas atmosphere, and is drawn toward the outlet of the furnace muffle tube by means of a specified drawing tension. The optical fiber preform and the drawing furnace used in this method both satisfy the condition of below-indicated formula (1): L/D?8??(1) wherein L indicates the length of the furnace body in the drawing direction and D indicates the diameter of the optical fiber preform.

Abstract: The present invention provides fluorescent glass containing at least 50 mol % of at least one kind of oxide selected from the group consisting of SiO2, GeO2, and P2O5 as a glass constituent of a region containing a Bi ion as a dopant.

Abstract: A furnace for drawing an optical fiber provided with a muffle tube (10) and inner tubes (5,5′) connected to the upper end of the core tube, wherein a preform (1) supported by a dummy rod (2) at the upper part thereof is disposed inside the muffle tube (10) and inner tubes (5,5′) so as to be movable downward together with dummy rod (2), the preform (1) is heated and melted by a heater (11) from the outside of the muffle tube (10) and an optical fiber (1a) is pulled out from the lower end of the preform (1); the furnace is further provided with one or a plurality of sets of separating plates (4, 17) adapted to partition a space in the inner tubes (5,5′) above the preform (1) into a plurality of portions in the advance direction of the preform and disposed in the space, and with gas blowing inlets (8) disposed in the parts of wall surfaces of the inner tubes (5,5′) which are below the separating plates (4, 17) and adapted to blow an inert gas into the inner tubes (5,5′) and the muff

Abstract: Based on an intermediate 20A in which a cladding portion 22 is formed on the outer periphery of a core portion 21, a pair of holes 23 and 24 are provided parallel to the z axis on both sides of the core portion 21 within the cladding portion 22, and an intermediate 20 is thereby fabricated. In this intermediate 20, a width Ry in the y-axis direction is made smaller than a width Rx in the x-axis direction. Moreover, a cylindrical stress applying part 33 is inserted into a hole 23 of the intermediate 20, and a cylindrical stress applying part 34 is inserted into a hole 24 thereof. Thus, a preform 40 is formed. These materials are drawn and integrated together, and a polarization maintaining optical fiber is thereby manufactured.

Abstract: A fiber drawing method according to the present invention is a drawing method of optical fiber for drawing an optical fiber 14 from one end of a fiber preform 13 by softening with heat, wherein the fiber preform 13 is set in a semi-closed space 10, 20 opening in part at a lower end in a fiber drawing furnace, the fiber preform 13 is heated by a heater 15 disposed on the lower end side of this semi-closed space 10, 20, and fiber drawing is carried out with adjusting a quantity of heat dissipation from the upper portion 20 of this semi-closed space.

Abstract: A furnace for drawing an optical fiber provided with a muffle tube (10) and inner tubes (5,5′) connected to the upper end of the core tube, wherein a preform (1) supported by a dummy rod (2) at the upper part thereof is disposed inside the muffle tube (10) and inner tubes (5,5′) so as to be movable downward together with dummy rod (2), the preform (1) is heated and melted by a heater (11) from the outside of the muffle tube (10) and an optical fiber (1a) is pulled out from the lower end of the preform (1); the furnace is further provided with one or a plurality of sets of separating plates (4, 17) adapted to partition a space in the inner tubes (5, 5′) above the preform (1) into a plurality of portions in the advance direction of the preform and disposed in the space, and with gas blowing inlets (8) disposed in the parts of wall surfaces of the inner tubes (5, 5′) which are below the separating plates (4,17) and adapted to blow an inert gas into the inner tubes (5,5′) and the muf

Abstract: A furnace for drawing an optical fiber provided with a muffle tube (10) and inner tubes (5, 5′) connected to the upper end of the core tube, wherein a preform (1) supported by a dummy rod (2) at the upper part thereof is disposed inside the muffle tube (10) and inner tubes (5, 5′) so as to be movable downward together with dummy rod (2), the preform (1) is heated and melted by a heater (11) from the outside of the muffle tube (10) and an optical fiber (1a) is pulled out from the lower end of the preform (1); the furnace is further provided with one or a plurality of sets of separating plates (4, 17) adapted to partition a space in the inner tubes (5, 5′) above the preform (1) into a plurality of portions in the advance direction of the preform and disposed in the space, and with gas blowing inlets (8) disposed in the parts of wall surfaces of the inner tubes (5, 5′) which are below the separating plates (4, 17) and adapted to blow an inert gas into the inner tubes (5, 5′) and the

Abstract: In an optical fiber coating method comprising the steps of; applying an injecting first coating resin to the outer periphery of the optical fiber while inserting the optical fiber through a first die hole provided in a first coating die; and applying an injected second coating resin onto the first coating resin while inserting the optical fiber through a second die hole provided in a second coating die.

Abstract: There is provided an optical fiber drawing furnace capable of drawing an optical fiber having small non circularity, which drawing furnace includes a muffle tube, in which an optical fiber preform is supplied, a heater surrounding the muffle tube, a plurality of electrode connecting portion extending from the heater, a plurality of electrodes connected to electrode connecting portions, and in conjunction therewith to an electric power source, and unifying means for unifying the temperature distribution along the circumferential direction.

Abstract: In an optical fiber coupler making apparatus which makes an optical fiber coupler by thermally fusing a plurality of optical fibers together by use of a heater and then elongating thus thermally fused part, the heater comprises a heating element which is made of zirconia and which has a slit for containing the optical fibers. The inner face of the heating element is preferentially heated due to a characteristic of its material. Consequently, if optical fibers are contained in the fiber receiving slit, then they can be thermally fused at a sufficiently high temperature in a short period of time, whereby reducing mingling of impurities into the optical fiber coupler. Therefore, the heating element made of zirconia is effective as means for preventing impurities from mingling from the outside thereof. Also, performances of the heating element can be maintained over a long period of time even if the optical fibers are thermally fused at a high temperature.

Abstract: A method of drawing an optical fiber which can improve the efficiency in manufacture without deforming resin coatings is provided.

Abstract: A method of making an optical fiber employing a wavelength in an infrared region as a wavelength band in use is provided, in which an optical fiber 1 is exposed to an atmosphere containing hydrogen at a concentration of 0.05 vol % but not higher than 4.0 vol % after being drawn and taken up with a bobbin 2 before being put into use, whereas the hydrogen treatment temperature is lower than 50° C., preferably 30° C. or lower, more preferably at room temperature, whereby the increase in loss caused by hydrogen is small even when the optical fiber is used in a wide band, so that the optical fiber can be made efficiently and safely with an optimal hydrogen treatment.

Abstract: In an optical fiber coating method comprising the steps of; applying an injecting first coating resin to the outer periphery of the optical fiber while inserting the optical fiber through a first die hole provided in a first coating die; and applying an injected second coating resin onto the first coating resin while inserting the optical fiber through a second die hole provided in a second coating die.

Abstract: The drawing method of the present invention uses a drawing furnace comprising a furnace muffle tube, a furnace body and a heater. According to the method, an optical fiber preform is inserted from the inlet of the furnace muffle tube, the optical fiber preform is melted by means of a heater, under a specified gas atmosphere, and is drawn toward the outlet of the furnace muffle tube by means of a specified drawing tension.

Abstract: An optical fiber preform 2 having a viscosity ratio R&eegr;=&eegr;0/&eegr;t of 2.5 or less between the core average viscosity &eegr;0 and the total average viscosity &eegr;t is prepared, and is drawn by a drawing furnace 11 so as to yield an optical fiber 3, which is then heated to a temperature within a predetermined range so as to be annealed by a heating furnace 21 disposed downstream the drawing furnace 11. Here, upon annealing in the heating furnace 21, the fictive temperature Tf within the optical fiber lowers, thereby reducing the Rayleigh scattering loss. At the same time, the viscosity ratio condition of R&eegr;≦2.5 restrains the stress from being concentrated into the core, thereby lowering the occurrence of structural asymmetry loss and the like. Hence, an optical fiber which can reduce the transmission loss caused by the Rayleigh scattering loss and the like as a whole, and a method of making the same can be obtained.