JP2005221778A - Coated optical fiber and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated optical fiber which is capable of obtaining a stable rewinding property and enhancing the tight adhesion of a colored layer formed on the surface, and to provide a manufacturing method of the coated optical fiber. <P>SOLUTION: The coated optical fiber 1 is constituted by covering the circumference of a glass fiber 2 with a covering layer 3 having a surface 3a of the average surface roughness 0.5 to 10 nm and the maximum vertical difference ≤50 nm and forming a colored layer 4 on the surface 3a. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical fiber core wire in which a glass fiber is coated with an ultraviolet curable resin layer and a method for manufacturing the same, and in particular, stable rewindability is obtained and adhesion of a colored layer formed on the surface is improved. The present invention relates to an optical fiber core and a manufacturing method thereof.

  Conventionally, ultraviolet curable resin has been mainly used as a coating material for optical fibers, and the fiber drawing speed has been increased and the drawing length has been increased (for example, see Patent Document 1).

  Usually, as a quality check after drawing, a proof test that also serves as rewinding is performed. The proof test is a test for examining the presence or absence of a defect portion having a low strength in the glass of an optical fiber, and rewinding is performed by applying a certain tension. Since this proof test also runs the fiber at high speed, static electricity due to friction tends to occur on the fiber surface.

  For this reason, there is a problem that the optical fiber is disturbed and transmission loss is increased, and this is usually dealt with by installing a static eliminating device (see, for example, Patent Document 2).

In addition, when the tackiness (stickiness) of the surface of the optical fiber core is strong, winding disturbance is likely to occur. Therefore, additives such as a leveling agent are blended in the UV curable resin in order to impart surface lubricity and smoothness. It is.
JP 2000-193855 A JP-A-8-110417

  However, in order to keep the static elimination performance of the static eliminator stable, it is necessary to frequently perform sensor maintenance, and it may be greatly affected by the surrounding humidity, and the static elimination effect is often not fully demonstrated. . For this reason, there is a problem that winding disturbance occurs at the time of rewinding, transmission loss increases, and rewinding needs to be performed again.

  Further, when a lot of additives such as a lubricant are blended in the coating material in order to impart lubricity to the surface, there is a problem that the adhesion between the outer layer of the optical fiber core wire and the colored layer provided for identification decreases. In the case of tape fibers in which multiple colored optical fiber cores with weak adhesion of the colored layer are lined up and covered with UV-curing resin, etc., the colored layer will not peel off when the coating layer is removed at the time of terminal construction. Resulting in poor identification. Furthermore, in warm water, a blister occurs between the colored layer and the lower layer, which causes a problem that transmission loss increases.

  Accordingly, it is an object of the present invention to provide an optical fiber core and a method for manufacturing the same, in which stable rewindability is obtained and adhesion of a colored layer formed on the surface is improved.

  In order to achieve the above object, the present invention provides an optical fiber core in which an ultraviolet curable resin layer is formed on the outer periphery of a glass fiber, and the ultraviolet curable resin layer has an average surface roughness of 0.5 to 10 nm. An optical fiber core having a maximum height difference of 50 nm or less is provided.

  The ultraviolet curable resin layer preferably has an average surface roughness of 0.5 to 5 nm and a maximum height difference of 20 nm or less.

In order to achieve the above object, the present invention applies an ultraviolet curable resin to the outer periphery of the glass fiber,
The glass fiber coated with the uncured ultraviolet curable resin is passed through a quartz tube into which an inert gas flows, and the glass fiber is irradiated with ultraviolet light through the quartz tube, thereby uncured ultraviolet curing. In an optical fiber core manufacturing method for manufacturing an optical fiber core by curing a resin, by adjusting an oxygen concentration in the inert gas flowing into the quartz tube to a predetermined amount, An optical fiber core manufacturing method characterized by roughening the surface is provided.

  It is preferable to adjust the oxygen concentration in the inert gas to 5000 to 50000 ppm.

  According to the optical fiber core wire of the present invention, good rewindability can be obtained by setting the average surface roughness of the surface of the ultraviolet curable resin layer protecting the glass fiber to 0.5 to 10 nm and the maximum height difference to 50 nm or less. And the adhesion of the colored layer formed on the surface is improved.

  By setting the average surface roughness of the surface of the ultraviolet curable resin layer to 0.5 to 5 nm and the maximum height difference to 20 nm or less, more stable rewindability can be obtained.

  According to the method for producing an optical fiber core of the present invention, by roughening the surface of the ultraviolet curable resin that protects the glass fiber, good rewindability can be obtained, and the colored layer formed on the surface can be obtained. Adhesion is improved.

  The desired surface roughness can be obtained by adjusting the oxygen concentration in the inert gas supplied when the ultraviolet curable resin is cured to 5000 to 50000 ppm.

  FIG. 1 shows a colored optical fiber core according to an embodiment of the present invention. As shown in FIG. 2A, the colored optical fiber core 1 has a coating layer 3 having a surface 3a having an average surface roughness of 0.5 to 10 nm and a maximum height difference of 50 nm or less around the glass fiber 2. And a colored layer 4 is formed on the surface 3a. In addition, the same figure (b) shows the optical fiber core wire 1a before forming the colored layer 4. FIG.

  The glass fiber 2 is made of, for example, quartz glass and is used for transmission of information communication and the like, but the material is not particularly limited.

  The covering layer 3 has, for example, a two-layer structure of a first covering layer 30 made of a relatively soft UV curable resin and a second covering layer 31 made of a relatively hard UV curable resin. In addition, the material of the 1st and 2nd coating layers 30 and 31 may be the same, and will not be specifically limited if it is used for an optical fiber, For example, urethane acrylate, ester acrylate, Commercially available products such as epoxy acrylate can be used.

  The average surface roughness of the surface 3a of the coating layer 3 is set to 0.5 to 10 nm, and the maximum height difference is set to 50 nm or less. If the roughness is smaller than 0.5 nm, it is applied for rewinding and identification. This is because the adhesion effect to the colored layer 4 cannot be obtained. Further, if the average surface roughness is larger than 10 nm, winding disturbance is likely to occur during rewinding. Furthermore, if the maximum height difference of the roughness of the surface 3a is larger than 50 nm, turbulence is likely to occur during rewinding. Preferably, the average surface roughness is 0.5 to 5 nm and the maximum height difference is 20 nm or less.

  FIG. 2 shows an ultraviolet irradiation device for curing the ultraviolet curable resin that becomes the coating layer 3, wherein (a) shows a one-lamp type and (b) shows a two-lamp type. The ultraviolet irradiation device 10A shown in FIG. 2 (a) includes a first coating layer 30 or a second coating layer 31 along the longitudinal direction in a space partitioned in a cylindrical shape by a pair of reflectors 11A and 11B. The quartz tube 12 that passes the optical fiber core wire 1a coated with the ultraviolet curable resin is disposed, the ultraviolet irradiation lamp 13 is disposed in parallel with the quartz tube 12 in the vicinity thereof, and the inert gas is introduced into the inert gas introduction path. 14 is introduced into the quartz tube 12 and discharged from the inert gas discharge passage 15.

  The ultraviolet irradiation device 10B shown in FIG. 2 (b) uses two ultraviolet irradiation lamps 13, and the other configuration is the same as the ultraviolet irradiation device 10A shown in FIG. 2 (a). It is preferable that the ultraviolet irradiation device 10A shown in FIG. 2A and the ultraviolet irradiation device 10B shown in FIG.

  As the ultraviolet irradiation lamp 13, a commercially available lamp such as a low-pressure mercury lamp, a high-pressure discharge lamp, or a metal halide lamp can be used. Preferably, a metal halide lamp is desirable. Either an electrode type or an electrodeless type may be used.

  As the inert gas, for example, nitrogen gas having an oxygen concentration of 5000 to 50000 ppm is used. The reason why the oxygen concentration in the inert gas is set to 5000 to 50000 ppm is that when it is less than 5000 ppm, the roughness of the surface 3a of the optical fiber core wire 1a is small, and a roughening effect cannot be obtained. On the other hand, when the content is more than 50000 ppm, the roughness of the surface 3a is increased, the curability of the surface 3a is remarkably reduced, and the surface 3a is easily adhered. When the optical fiber core wire 1 is wound around a bobbin, This is because problems such as the cores 1a sticking to each other or winding disorder occur. Preferably, 10000-30000 ppm is good.

  Next, an example of a manufacturing method of the colored optical fiber core wire 1 using the ultraviolet irradiation devices 10A and 10B will be described. An optical fiber core wire is applied from the ultraviolet irradiation lamp 13 while applying an ultraviolet curable resin to the glass fiber 2 and passing it through the quartz tube 12 to which the inert gas of the ultraviolet irradiation apparatus 10A shown in FIG. An uncured ultraviolet curable resin is cured by irradiating 1a with ultraviolet rays to form a first coating layer 30 on the optical fiber core wire 1a.

  Next, an ultraviolet curable resin is applied onto the cured first coating layer 30, and an ultraviolet curable resin is applied to the glass fiber 2, which is supplied by the inert gas of the ultraviolet irradiation device 10 </ b> B shown in FIG. While passing through the quartz tube 12, the optical fiber core 1a is irradiated with ultraviolet rays from the two ultraviolet irradiation lamps 13 to cure the uncured ultraviolet curable resin, and the second coating on the optical fiber core 1a. Layer 31 is formed. Thereby, the optical fiber core wire 1a having an average surface roughness of the surface 3a of the coating layer 3 of 0.5 to 10 nm and a maximum height difference of 50 nm or less is obtained.

  Next, the colored optical fiber core wire 1 is obtained by forming the colored layer 4 on the cured second coating layer 31.

  3, 4, and 5 illustrate a tape fiber in which a plurality of colored optical fiber cores 1 illustrated in FIG. 1A are covered with a tape material 5. 3 shows a two-core tape fiber 20A using two colored optical fiber cores 1, FIG. 4 shows a four-core tape fiber 20B using four colored optical fiber cores 1, and FIG. 8 core tape fibers 20C using the colored optical fiber core wire 1 are respectively shown.

  An optical fiber core manufacturing method according to Example 1 of the present invention will be described. In the first embodiment, the oxygen concentration in the nitrogen gas flowing into the quartz tubes 12 of the ultraviolet irradiation apparatuses 10A and 10B is set to 10,000 ppm, and this nitrogen gas is allowed to flow in the direction opposite to the traveling direction of the optical fiber core 1a. Light obtained by curing the first coating layer 30 using the 6 kW single-lamp ultraviolet irradiation device 10A (lamp length 250 mm) shown in FIG. 2A for the first coating layer 30 constituting the core wire 1a. The second coating layer 31 constituting the fiber core wire 1a is drawn at a drawing speed of 1200 m / min using a 6 kW two-lamp ultraviolet irradiation device 10B (lamp length of 250 mm) shown in FIG. 2B. The optical fiber core wire 1a shown in 1 (b) was drawn by 550 km. About this optical fiber core wire 1a, the average surface roughness and the maximum height difference of the surface 3a of the coating layer 3 were investigated with the scanning probe microscope (SPI3800N station Seiko Instruments Co., Ltd. product). In addition, 20 25-km bobbins were prepared using a proof and rewinding device, and the presence or absence of a step was examined using an OTDR (Optical Time Domain Refractometer) device. Next, in the coloring step, a colored optical fiber core 1 shown in FIG. 1A in which a colored layer 4 is applied to the optical fiber core 1a is prepared, and three 1000 m bundles are prepared and immersed in warm water at 60 ° C. (The terminal was taken out of the hot water tank), and the change over time in the transmission loss was measured for 30 days.

  A method for manufacturing an optical fiber core according to Embodiment 2 of the present invention will be described. In the second embodiment, the oxygen concentration in the nitrogen gas flowing into the quartz tubes 12 of the ultraviolet irradiation devices 10A and 10B is 20000 ppm, and the first coating layer 30 constituting the optical fiber 1a is shown in FIG. 6 kW single-lamp ultraviolet irradiation device 10A (lamp length 250 mm) shown in FIG. 2B, and 6 kW dual-lamp ultraviolet irradiation device 10B (lamp length 250 mm each) shown in FIG. ), A sample was prepared and tested in the same manner as in Example 1 for the optical fiber core wire 1a obtained by drawing 550 km at a drawing speed of 1200 m / min.

  An optical fiber core manufacturing method according to Example 3 of the present invention will be described. In the third embodiment, the oxygen concentration in the nitrogen gas flowing into the quartz tubes 12 of the ultraviolet irradiation devices 10A and 10B is 30000 ppm, and the first coating layer 30 constituting the optical fiber core 1a is shown in FIG. 6A single lamp type ultraviolet irradiation device 10A (lamp length 250 mm) shown in FIG. 2A, and 6 kW double lamp type ultraviolet irradiation device 10B (lamp length shown in FIG. 2B) with respect to the second coating layer 31. Each of the optical fiber cores 1a obtained by drawing 550 km at a drawing speed of 1200 m / min using 250 mm) was prepared and tested in the same manner as in Example 1.

Comparative Example 1

  The manufacturing method of the optical fiber core wire which concerns on the comparative example 1 is demonstrated. In Comparative Example 1, the oxygen concentration in the nitrogen gas flowing into the quartz tubes 12 of the ultraviolet irradiation apparatuses 10A and 10B is set to 4000 ppm, and the first coating layer 30 constituting the optical fiber core wire 1a is illustrated in FIG. 6 kW single-lamp ultraviolet irradiation device 10A (lamp length 250 mm) shown in FIG. 2B, and 6 kW dual-lamp ultraviolet irradiation device 10B (lamp length 250 mm each) shown in FIG. ), A sample was prepared and tested in the same manner as in Example 1 for the optical fiber core wire 1a obtained by drawing 550 km at a drawing speed of 1200 m / min.

Comparative Example 2

  The manufacturing method of the optical fiber core wire which concerns on the comparative example 2 is demonstrated. In Comparative Example 2, the oxygen concentration in the nitrogen gas flowing into the quartz tubes 12 of the ultraviolet irradiation apparatuses 10A and 10B is 60000 ppm, and the first coating layer 30 constituting the optical fiber core 1a is shown in FIG. A 6 kW 1 lamp type ultraviolet irradiation apparatus 10A (lamp length 250 mm) and a 6 kW 2 lamp type ultraviolet irradiation apparatus 10B (lamp length 250 mm each) shown in FIG. 3 for the second coating layer 31, and a drawing speed of 1200 m / min. A sample of the optical fiber core wire 1a obtained by drawing at 550 km in the same manner as in Example 1 was tested.

表１は、実施例１，２，３および比較例１，２で測定を行った段差発生数と６０℃温水浸漬時の伝送損失結果を示す。

Table 1 shows the number of steps generated in Examples 1, 2, and 3 and Comparative Examples 1 and 2 and the transmission loss result when immersed in 60 ° C. warm water.

  As is apparent from Table 1, in Examples 1, 2 and 3, the number of OTDR steps generated due to rewinding is smaller than in Comparative Examples 1 and 2, and an increase in transmission loss occurs when immersed in hot water at 60 ° C. Difficult things have been obtained.

  FIG. 6 shows an example in which the surface roughness of the surface 3a of the optical fiber core wire 1a drawn with an oxygen concentration of 20000 ppm in Example 2 was measured with a scanning probe microscope (SPI3800N manufactured by Seiko Instruments Inc.). FIG. 6A shows the surface roughness of a 5 × 5 μm region, and FIG. 6B shows the profile of the surface roughness on a certain line.

  As is clear from this, by setting the average surface roughness of the surface 3a of the optical fiber core 1a to 0.5 to 10 nm, it is possible to obtain an optical fiber core excellent in rewindability.

(A) is sectional drawing of the colored optical fiber cable which concerns on embodiment of this invention, (b) is sectional drawing of the optical fiber cable before forming a colored layer. The ultraviolet irradiation apparatus for hardening the ultraviolet curable resin of the optical fiber core wire which concerns on embodiment of this invention is shown, (a) is a figure which shows a 1 lamp type ultraviolet irradiation apparatus, (b) is a 2 lamp type It is a figure which shows an ultraviolet irradiation device. It is sectional drawing which shows the tape fiber using two colored optical fiber core wires which concern on embodiment of this invention. It is sectional drawing which shows the tape fiber using four colored optical fiber core wires which concern on embodiment of this invention. It is sectional drawing which shows the tape fiber using eight colored optical fiber core wires which concern on embodiment of this invention. The surface roughness of the surface 3a of the optical fiber core wire 1a drawn with an oxygen concentration of 20000 ppm in Example 2 of the present invention is shown by a scanning probe microscope, and (a) shows the surface roughness of a 5 × 5 μm region. (B) is a photograph showing a profile of surface roughness on a certain line.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Colored optical fiber core wire 1a Optical fiber core wire 2 Glass fiber 3 Coating layer 3a Surface of coating layer 4 Colored layer 5 Tape material 10A, 10B Ultraviolet irradiation apparatus 11A, 11B Reflector plate 12 Quartz tube 13 Ultraviolet irradiation lamp 14 Inert gas Introduction path 15 Inert gas discharge paths 20A, 20B, 20C Tape fiber 30 First coating layer 31 Second coating layer

Claims (4)

In an optical fiber core wire in which an ultraviolet curable resin layer is formed on the outer periphery of the glass fiber,
The ultraviolet curable resin layer has an average surface roughness of 0.5 to 10 nm and a maximum height difference of 50 nm or less.   The optical fiber core wire according to claim 1, wherein the ultraviolet curable resin layer has an average surface roughness of 0.5 to 5 nm and a maximum height difference of 20 nm or less. Apply UV curable resin to the outer periphery of the glass fiber,
The glass fiber coated with the ultraviolet curable resin is passed through a quartz tube into which an inert gas flows, and the glass fiber is irradiated with ultraviolet rays through the quartz tube to cure the uncured ultraviolet curable resin. In the manufacturing method of the optical fiber core wire to manufacture the optical fiber core wire,
A method of manufacturing an optical fiber core, wherein the surface of the ultraviolet curable resin is roughened by adjusting an oxygen concentration in the inert gas flowing into the quartz tube to a predetermined amount.   The method for manufacturing an optical fiber core wire according to claim 3, wherein the oxygen concentration in the inert gas is adjusted to 5000 to 50000 ppm.

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