JP2005070332A - Coated optical fiber, coated optical fiber tape, and discrimination method of coated optical fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated optical fiber, a coated optical fiber tape, and a discrimination method of coated optical fiber in which detection of leakage light is facilitated and in which detection sensitivity of core wire discriminating light is improved. <P>SOLUTION: Pigment particulates 7a having a refractive index different from that of the outer layer 7 coating material are added to the outer layer 7 of an optical fiber 3 having UV resin coated inner and outer layers 5, 7.. The optical fiber 3 when bent has the capability to reduce coupling loss of leakage light. In other words, by bending the optical fiber 3, test light is designed to be scattered without being totally reflected in the boundary between the optical fiber and the air layer. In addition, bending the optical fiber 3 using this characteristic improves the detection sensitivity of the discriminating light for the coated optical fiber. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical fiber core wire, an optical fiber tape core wire, and a method for discriminating them, and in particular, an optical fiber core wire capable of discriminating individual optical fiber core wires during construction and maintenance of an optical fiber cable. The present invention relates to an optical fiber ribbon and a method for discriminating an optical fiber.

  As shown in FIG. 8, a single optical fiber core wire 101 is composed of a two-layer ultraviolet curable resin (hereinafter referred to as UV resin) on a quartz fiber composed of a core and a clad, that is, an optical fiber (outer diameter 125 μm) 103. (The outer diameter is 250 μm) A structure in which the coating layer 105 is coated is generally used.

  On the other hand, as shown in FIG. 9, the multi-fiber optical fiber ribbon 107 has the required number (usually 2, 4, 8, 12, 16) of the single-fiber optical fibers 101 of FIG. A structure in which the taped UV resin layer 109 is collectively coated thereon is generally used.

  By the way, it is necessary to confirm whether or not a plurality of optical cable cores are correctly connected in series in the longitudinal direction after laying the optical cable cores or at the time of maintenance and inspection. Therefore, test light (modulated optical signals such as 270 Hz, 1 kHz, 2 kHz, etc.) are incident on the individual optical fibers in the optical cable core from the station side. 10 (a) and 10 (b), the light is transmitted by the clamp concave portion 113 and the clamp convex portion 115 of the core wire contrast device (also referred to as ID tester, core wire discriminator or core wire discriminator) 111. By sandwiching the fiber core 101 and making the optical fiber core 101 a small bending radius (usually a bending radius of 3 to 10 mm) along the groove 115a formed in the clamp protrusion 115 as shown in FIG. This test light can be detected as leakage light by the photodiode 117 which is a light receiving unit, and the individual optical fiber cores 101 can be discriminated.

  That is, if an erroneous optical fiber core wire is cut in an optical cable connection work, a serious accident such as a line stop occurs. As means for preventing this, an optical signal for core-line discrimination modulated from the station side is incident on the optical fiber core 101 to be cut as described above, and the optical fiber core 101 is connected at the connection point of the cable. The optical fiber core wire is discriminated by detecting the optical signal for discriminating the core wire that has leaked due to bending to the photo diode 117 of the core wire contrast device 111.

As a conventional apparatus capable of searching for an optical fiber core wire and measuring optical power, there is one disclosed in Patent Document 1, for example. This optical power measuring device includes a main body part having a photoelectric converter insertion part holding a photoelectric converter at a tip part, and a core line search head that is formed so that the photoelectric converter insertion part can be inserted and sandwiches an optical fiber. And an optical power measuring head that is formed so that the photoelectric converter insertion portion can be inserted and can connect the specified optical fiber.
Japanese Patent Laid-Open No. 11-223573

  However, in the case of the optical fiber core wire 101 having the conventional structure as shown in FIG. 8 and the optical fiber tape core wire 107 shown in FIG. 9, as shown in FIG. Most of the test light is totally reflected at the boundary surface, and only the leaked light having a weak detection limit is detected. Therefore, it becomes a cause of misjudgment whether it is the said optical fiber.

  That is, in the detector that detects the optical signal for discriminating the core wire, an air gap (air layer) is generated between the optical fiber core wire and the light receiving unit. Since the refractive index of air is lower than that of the coating material of the optical fiber, the leaked light leaking from the optical fiber due to bending is reflected at the interface between the coating material and the air layer, and the light intensity detected by the detector is high. There is a problem that it becomes low and cannot be detected.

  As shown in FIG. 13, according to Snell's law, leakage light (transmitted light in FIG. 13) is obtained with respect to a normal line perpendicular to the boundary surface between the substance 1 (refractive index N1) and the substance 2 (refractive index N2). ), The incident angle of the incident light from the substance 1 must be smaller than the critical angle Tc. Otherwise, the incident light is totally reflected and returns to the substance 1. In order to detect more leaked light, the bending radius of the optical fiber may be reduced. However, the smaller the bending radius, the greater the risk of optical fiber breakage.

  As a specific example, if the substance 1 is a UV resin, N1 = 1.5, and the substance 2 is a void, N2 = 1. Therefore, from Snell's equation, the critical angle Tc = 0.73 [rad] or 42 [°] Become.

That is, according to Snell's law, if the incident angle is θ1 and the transmission angle is θ2,
[Equation 1]
N1 × sin (θ1) = N2 × sin (θ2)
When the incident angle is the critical angle Tc at which total reflection occurs, θ2 = π / 2 in the above equation.
[Equation 2]
N1 × sin (Tc) = N2 × sin (π / 2)
[Equation 3]
Tc = sin ⁻¹ (N2 / N1)
Here, when the substance 1 is a UV resin and N1 = 1.5 and the substance 2 is an air layer and N2 = 1, the critical angle Tc = 0.73 [rad] or 42 [°].

  The present invention has been made in view of the above, and as an object thereof, an optical fiber core wire, an optical fiber tape core wire, and an optical fiber that facilitate the detection of leakage light and improve the detection sensitivity of the core wire discrimination light. The object is to provide a method for discriminating a core wire.

  The gist of the invention described in claim 1 is that, in order to solve the above-described problems, fine particles having a refractive index different from that of the coating material are added to the coating material of the optical fiber.

  In order to solve the above problems, the invention according to claim 2 is summarized in that the covering material is an ultraviolet curable resin.

  In order to solve the above-mentioned problems, the gist of the invention described in claim 3 is that the fine particles are inorganic pigment fine particles.

  In order to solve the above problems, the invention according to claim 4 is characterized in that the inorganic pigment fine particles are at least one material selected from Gunjo, Bengala, carbon black, and titanium white.

  In order to solve the above problems, the invention according to claim 5 is summarized in that the fine particles are organic pigment fine particles.

  In order to solve the above problems, the invention according to claim 6 is characterized in that the organic pigment fine particles are at least one material selected from azo, triphenylmethane, anthraquinone, and phthalocyanine. .

  In order to solve the above problems, the invention according to claim 7 is characterized in that the inorganic pigment fine particles and the organic pigment fine particles have a particle diameter of 0.01 to 10 μm.

  The gist of the invention described in claim 8 is that, in order to solve the above problems, a plurality of the optical fiber cores according to any one of claims 1 to 6 are taped in parallel.

  In order to solve the above problems, the invention according to claim 9 is a bending step of bending a fiber core wire in which pigment fine particles having a refractive index different from that of the coating material are added to the coating material of the optical fiber, and the optical fiber core wire. An optical signal incident step for causing an optical signal for core wire discrimination to enter the optical signal, and an optical signal detection step for detecting the optical signal for core wire discrimination leaked from the bent portion of the optical fiber core wire. The gist.

  According to the first aspect of the present invention, since fine particles having a refractive index different from that of the coating material are added to the coating material of the optical fiber, leakage from the bent portion of the optical fiber within the coating material By detecting the scattering of light, changing the incident angle at the interface between the covering material and the air layer, and reducing the reflection attenuation, it is possible to improve the detection sensitivity of the core line discrimination light.

  According to the second aspect of the present invention, since the coating material is an ultraviolet curable resin, it can be cured in a short time and the environmental resistance can be improved.

  According to the third aspect of the present invention, since the fine particles are inorganic pigment fine particles, it is possible to reduce the coupling loss of leaked light due to the bending of the optical fiber core wire.

  According to the fourth aspect of the present invention, since the inorganic pigment fine particles are at least one material selected from Gunjo, Bengala, carbon black, and titanium white, the bending of the optical fiber core as in the third aspect. It is possible to reduce the coupling loss of leaked light.

  According to the fifth aspect of the present invention, since the fine particles are organic pigment fine particles, similarly to the third aspect, it is possible to reduce the coupling loss of the leaked light due to the bending of the optical fiber core wire.

  According to the sixth aspect of the present invention, since the organic pigment fine particles are at least one material selected from azo, triphenylmethane, anthraquinone, and phthalocyanine, the optical fiber as in the third aspect. It is possible to reduce the coupling loss of the leaked light due to the bending of the core wire.

  According to the seventh aspect of the present invention, since the inorganic pigment fine particles and the organic pigment fine particles have a particle size of 0.01 to 10 μm, the dispersibility of the inorganic pigment fine particles and the organic pigment fine particles in the coating material is improved. Can be improved.

  According to the eighth aspect of the present invention, a plurality of the optical fiber cores according to any one of the first to sixth aspects are taped in parallel, so that the core discrimination light in the plurality of optical fiber cores can be obtained. Detection sensitivity can be improved.

  According to the ninth aspect of the present invention, a fiber core wire obtained by adding fine particles having a refractive index different from that of the coating material to the coating material of the optical fiber is bent, and an optical signal for discriminating the core wire is applied to the optical fiber core wire. The optical fiber core wire can be reliably and easily discriminated by detecting the optical signal for determining the core wire that has entered and leaked from the bent portion of the optical fiber core wire.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view showing an optical fiber core wire according to the first embodiment of the present invention.

  As shown in FIG. 1, an optical fiber core wire 1 of the present embodiment includes an optical fiber 3 composed of a core and a clad, a UV resin coating layer 5 provided on the outer periphery of the optical fiber 3, and the UV resin coating. The outer periphery of the layer 5 is coated with a UV resin layer 7 as a coating material in which pigment fine particles 7a are added and dispersed as fine particles having a refractive index different from that of the UV resin.

  The pigment fine particles 7a added to the UV resin layer 7 are inorganic pigment organic particles or organic pigment fine particles having a refractive index different from that of the UV resin and having a particle diameter of 0.01 to 10 μm. The fine particles include at least one material selected from Gunjo, Bengala, carbon black, and titanium white, while the organic pigment fine particles include at least one selected from azo, triphenylmethane, anthraquinone, and phthalocyanine. Materials. When the particle size of the inorganic pigment organic particles or organic pigment fine particles is out of the range of 0.01 to 10 μm, the dispersibility of the fine particles with respect to the UV resin as the coating material is lowered.

  FIGS. 2A and 2B are configuration diagrams showing a measurement system for measuring the coupling loss of leaked light due to bending of the optical fiber core in this embodiment, and FIG. 2A is an optical fiber core. 1 indicates that the optical fiber is in a straight state, and FIG. 2B shows a leakage light detection state in which the optical fiber core wire is bent.

  FIG. 3 is an explanatory diagram showing a leaked light detection state in which the optical fiber core wire is bent in the present embodiment.

  FIG. 4 is a process diagram showing a method of discriminating an optical fiber core wire in the present embodiment.

  FIG. 5 is an explanatory diagram showing the measurement result of the coupling loss by the measurement system of FIGS. 2 (a) and 2 (b).

  2A and 2B, the optical fiber core wire is coated with a UV resin on an optical fiber conforming to SSMA-9.5 / 125 defined in JIS C 6835. 250 μm.

  As shown in FIGS. 2A, 2B and 3, the optical fiber core wire 1 is sandwiched between the clamp concave portion 11 and the clamp convex portion 13 of the optical fiber contrast device 9, and the optical fiber core wire 1 has a small bending radius. (Normally, a bending radius of 3 to 10 mm) (step P1 in FIG. 4).

  Next, test light (optical signal) having a wavelength of 1.55 μm, which is an optical signal for discriminating the core wire, is incident from the stabilizing light source 15, and the test light is attenuated by the optical attenuator 17 and incident on the optical fiber core wire 1. (Step P2 in FIG. 4).

  Further, leakage light (detection light) leaked from the bent portion of the optical fiber core wire 1 is detected by the photodiode 19 (step P3 in FIG. 4). Thus, the optical fiber core wire 1 can be discriminated by detecting the leaked light leaked by bending the optical fiber core wire 1 by the photodiode 19 of the core wire contrast device 9. Therefore, the test light is not totally reflected but rather scattered at the boundary surface between the UV resin layer 7 and the air gap, so that the leakage light can be easily detected by the photodiode 19.

  By the way, the coupling loss is expressed by Po-Pc (dB). Here, Po is the value (dBm) of the optical power meter 21 shown in FIGS. 2A and 2B when the optical fiber core wire 1 is straight, and Pc is the leakage from the bent portion of the optical fiber core wire 1. This is a value (dBm) of optical power obtained by measuring light with the photodiode 19.

  As shown in FIG. 5, in the case of UV resin to which black pigment fine particles are added as shown in FIG. 5, the measurement result of the coupling loss scatters part of the test light, but in most cases absorbs it, so the result is better than other colors. Is bad. However, in the case of colors other than black, the coupling loss is 19 to 23 dB, and the coupling loss is improved by 20 dB or more compared to the coupling loss of 45 dB in the case of only the conventional UV resin to which pigment fine particles are not added. I understand that.

  Therefore, according to the optical fiber core wire 1 in the present embodiment, the pigment fine particles 7a having a refractive index different from that of the UV resin are added to the UV resin layer 7 of the optical fiber 3. The leakage light leaking from the bent portion of the optical fiber 3 in the layer 7 is scattered, the incident angle at the interface between the UV resin layer 7 and the air layer is changed, and the reflection attenuation is reduced. Detection sensitivity can be improved. The pigment fine particles 7a can be used to visually distinguish the individual optical fiber cores 1.

  Moreover, according to the optical fiber core wire 1 in this Embodiment, since the coating material which added the pigment fine particle 7a was made into UV resin, it can harden | cure in a short time and can improve environmental resistance.

  Furthermore, according to the optical fiber core 1 in the present embodiment, since the pigment fine particles 7a are inorganic pigment organic particles or organic pigment fine particles, it is possible to reduce the coupling loss of leaked light due to the bending of the optical fiber core wire. it can. Since the inorganic pigment fine particles and the organic pigment fine particles have a particle size of 0.01 to 10 μm, the dispersibility of the inorganic pigment fine particles and the organic pigment fine particles in the UV resin layer 7 can be improved.

  The inorganic pigment fine particles are at least one material selected from Gunjo, Bengala, Carbon Black, and Titanium White, while the organic pigment fine particles are selected from azo, triphenylmethane, anthraquinone, and phthalocyanine. Since at least one kind of material is used, the coupling loss of leaked light due to the bending of the optical fiber core wire can be reduced.

  Furthermore, according to the method for discriminating the optical fiber core 1 in the present embodiment, the connection of the fiber core wire 1 in which pigment fine particles 7a having a refractive index different from that of the UV resin is added to the UV resin layer 7 of the optical fiber 3 is connected. Bending is applied at the location, test light for discriminating the optical fiber is made incident on the optical fiber core wire 1, and the test light for discriminating the optical fiber leaking from the bent portion of the optical fiber core wire 1 is detected as detection light. The optical fiber core wire 1 can be discriminated reliably and easily.

(Second Embodiment)
FIG. 6 is a cross-sectional view showing an optical fiber ribbon in the second embodiment of the present invention. Note that the same parts as those in the first embodiment are denoted by the same reference numerals, and only different configurations will be described.

  In this embodiment, as shown in FIG. 6, four optical fiber cores 1 in FIG. 1 are arranged in parallel, and a UV resin layer 23 is collectively coated thereon to form a four-fiber optical fiber ribbon 25. Formed.

  Thus, since the optical fiber ribbon 25 has four optical fibers 1 provided with the UV resin layer 7 to which the pigment fine particles 7a are added, the coupling loss is 20 to 24 dB as shown in FIG. It can be seen that the coupling loss is improved by about 20 dB compared to 42 dB in the case of only the conventional UV resin to which pigment fine particles are not added.

  Therefore, the optical fiber ribbon 25 has the configuration of each optical fiber 1 as described above, so that the core discrimination light in the plurality of optical fibers 1 is the same as in the first embodiment. The detection sensitivity can be improved, and the individual optical fiber cores 1 can be visually discriminated by the pigment fine particles.

It is sectional drawing which shows the optical fiber core wire in the 1st Embodiment of this invention. (A), (b) is a block diagram which shows the measurement system which measures the coupling loss of the leaked light by the bending of the optical fiber core wire in this Embodiment. In this Embodiment, an optical fiber core wire is bent and it is explanatory drawing which shows a leakage light detection state. It is process drawing which shows the discriminating method of the optical fiber core wire in this Embodiment. It is explanatory drawing which shows the measurement result of the coupling loss of this Embodiment. It is sectional drawing which shows the optical fiber tape cable core in the 2nd Embodiment of this invention. It is explanatory drawing which shows the measurement result of the coupling loss in 2nd Embodiment. It is sectional drawing which shows the conventional optical fiber core wire. It is sectional drawing which shows the conventional optical fiber tape core wire. (A), (b) is explanatory drawing which shows a core wire contrast device. It is an enlarged view which shows the clamp convex part of the core wire contrast device of FIG. It is explanatory drawing which shows the boundary surface of UV resin of an optical fiber covering, and a space | gap with the optical fiber core wire of FIG. It is explanatory drawing which shows the principle for detecting the transmitted light.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical fiber core wire 3 Optical fiber 5 UV resin coating layer 7 UV resin layer 7a Pigment particulate 9 Core wire contrast device 11 Clamp recessed part 13 Clamp convex part 15 Stabilizing light source 17 Optical attenuator 19 Photodiode 21 Optical power meter 23 UV resin Layer 25 optical fiber ribbon

Claims (9)

An optical fiber core, wherein fine particles having a refractive index different from that of the coating material are added to the coating material of the optical fiber. The optical fiber core wire according to claim 1, wherein the coating material is an ultraviolet curable resin. 2. The optical fiber core wire according to claim 1, wherein the fine particles are inorganic pigment fine particles. The optical fiber core wire according to claim 3, wherein the inorganic pigment fine particles are at least one material selected from Gunjo, Bengala, Carbon Black, and Titanium White. 2. The optical fiber core wire according to claim 1, wherein the fine particles are organic pigment fine particles. 6. The optical fiber core wire according to claim 5, wherein the organic pigment fine particles are at least one material selected from azo, triphenylmethane, anthraquinone, and phthalocyanine. The optical fiber core wire according to any one of claims 3 to 6, wherein the inorganic pigment fine particles and the organic pigment fine particles have a particle size of 0.01 to 10 µm. An optical fiber ribbon, wherein a plurality of the optical fiber strands according to any one of claims 1 to 6 are taped in parallel. A bending step of bending a fiber core wire in which pigment fine particles having a refractive index different from that of the coating material are added to the coating material of the optical fiber;
An optical signal incident step of causing an optical signal for core wire discrimination to enter the optical fiber core wire;
An optical signal detection step of detecting an optical signal for discriminating the core wire leaked from a bent portion of the optical fiber core wire;
A method for discriminating optical fiber cores, comprising:

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