JPH0623005U - Fixed structure of multi-fiber optical fiber split - Google Patents

Abstract

(57) [Abstract] [Purpose] When splitting a multi-core optical fiber into a single core, the split part is fixed and protected to ensure stable optical power. A housing 1 for accommodating and protecting the split portion 13 of the multi-fiber optical fiber 11 in a fixed structure of the split portion for protecting the split portion 13 obtained by splitting the multi-fiber optical fiber 11 into a single-core state.
6 and a lid, a protective tube 14 for protecting each of the divided single-core optical fibers 12, a multi-core optical fiber 11 after the division, and a single-core optical fiber 12 protected by the protective tube 14. Are fixed at the opening portions at both ends of the housing 16, and the elastic adhesive material 1 has rubber elasticity even after curing.
It consists of 7.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a structure for fixing a split portion of a multi-fiber optical fiber, which fixes and protects the split portion when the multi-fiber optical fiber is split into a single core.

[0002]

[Prior art]

 When a plurality of single-core optical fibers each having a coating outer diameter of 250 μm are bundled together with an adhesive and formed into a tape-like multi-fiber optical fiber, the fiber is split into a single-core state again by the required length. It is necessary to fix the splitting part in order to prevent abnormal bending of the single-core optical fiber immediately after it is made or to prevent the splitting from proceeding. In addition, since the divided portion is mechanically weakened, protection against external force is necessary. Furthermore, the split single-core optical fiber has an outer diameter of 250 μm, which is very thin, and is easily broken.

Conventionally, there has been a split fixing unit shown in FIG. 4 which satisfies such a function. The multi-core optical fiber 1 focused in a tape shape is divided into single-core optical fibers 3 by the dividing section 2, and one end of each of the divided single-core optical fibers 3 reaches close to the dividing section 2. The protective tube 4 is inserted in the. The split portion 2, the single-core optical fiber 3 immediately after splitting, and the end portion of the protective tube 4 were collectively covered with the thermosetting resin 5 having a large elastic modulus and hardened and fixed.

[0004]

[Problems to be solved by the device]

 However, in the structure of FIG. 4, when the temperature of the split fixing part changes, the thermal expansion coefficient of the resin is more than two orders of magnitude larger than that of the warp of the fiber, and the amount of resin per unit cross-sectional area is much larger than the amount of fiber. Since the resin is made of many and hard materials, a large stress is applied to the fiber due to the expansion and contraction of the resin, and the optical power that passes through the fiber changes greatly, so it cannot be used in a practical system that requires stable optical power. There were no drawbacks. Further, when the temperature change is repeatedly applied, there is a defect that the fiber often eventually causes fatigue fracture.

According to the present invention, even if a temperature change is applied to the split fixed portion, the stress generated in the fiber in the split fixed portion is reduced, and the change in the optical power passing through the optical fiber is made extremely small. It is an object of the present invention to provide a structure for splitting and fixing a multi-fiber optical fiber which solves the problem that stable optical power can be secured.

[0006]

[Means for Solving the Problems]

 The structure of the present invention that achieves the above-mentioned object is a housing and a lid for accommodating and protecting a split portion of a multi-fiber optical fiber in a fixed structure of the split portion that protects the split portion obtained by splitting the multi-fiber optical fiber into a single-core state. The housing section consisting of, the protective tube that protects each of the divided single-core optical fibers, and the above-mentioned divided multi-core optical fiber and the single optical fiber protected by the protective tube at the openings at both ends of the housing. It is characterized by being made of an elastic adhesive material which is fixed and cured and has rubber elasticity.

[0007]

[Action]

 In the above configuration, a protection tube is used to protect each of the split single-core optical fibers, and the split multi-core optical fiber is supported in the housing of the housing by floating in the hollow. The optical fiber and the protective tube are fixed using an elastic adhesive, and the lid is fitted into the housing to fix and protect the split portion of the multi-fiber optical fiber. Since the fiber at the split part is not covered with resin and is floated in the hollow and the elastic adhesive that maintains the soft elasticity that does not easily generate stress even when the temperature changes is applied, it does not light even when an external force with temperature change is applied. The change in power is small.

[0008]

【Example】

 Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view showing the internal structure of the split fixing portion, and FIG. 2 is a perspective view thereof. As shown in these drawings, a tape-shaped multi-core optical fiber 11 is divided into single-core optical fibers 12 at a dividing section 13, and each single-core optical fiber 12 is divided up to the vicinity of the dividing section 13. A protective tube 14 is inserted in the.

The tape-shaped multi-fiber optical fiber 11 having the split portion 13 with the protective tube 14 inserted therein is arranged in the housing 16 of the housing portion 15 so that the split portion 13 is supported in a hollow state. At the same time, the elastic adhesive material 17 is injected into and fixed to the openings of both ends of the housing 16.

In this embodiment, as the tape-shaped multi-core optical fiber 11, a single-core optical fiber 12 having an outer diameter of 0.25 mm is arranged in the axial direction without a gap and is converged by an adhesive to form a 4-core tape-shaped optical fiber. The cross-sectional size is about 0.25 × 1.0 mm. Further, the protective tube 14 inserted for protection from external force after being divided into the single-core optical fibers 12 is made of nylon having an outer diameter of 0.9 mm and an inner diameter of 0.5 mm.

Further, the accommodating portion 15 that protects the dividing portion 13 includes a housing 16 having a U-shaped cross section and a lid body 18. The housing 16 is formed by bending a stainless steel plate material having a thickness of 0.2 mm, as shown in FIG. The channel shape shown was used. In FIG. 3, the dimension A is 0.9 mm × 4 = 3.6 mm, which is the dimension in which four protective tubes 14 are lined up in a line. The dimension of B is 0.9 mm which is the outer diameter of the protective tube 14. On the other hand, the lid 18 is made of the same material and has the same shape as the housing 16, but can be fitted into the housing 16 by sliding.

The elastic adhesive material 17 for fixing the tape-shaped four-core optical fiber 11 and the four protective tubes 14 is a two-liquid mixing type high-viscosity adhesive material and exhibits rubber elasticity even after curing. It is a thing. An example of this elastic adhesive material is "EP001" (trade name) manufactured by Cemedine.

The fixing with the elastic adhesive is performed by dividing the multi-core optical fiber 11 and inserting the protective tubes 14 into the single-core optical fiber 12 one by one up to the vicinity of the dividing portion 13 and storing them in the housing 16 in this state. Then, while holding the multi-core optical fiber 11, the elastic adhesive material 17 is injected into the opening portions at both ends of the housing 16 so that the split portion 13 becomes hollow.

At this time, since the inner diameter of the protective tube 14 is 0.5 mm, the single-core optical fiber having an outer diameter of 0.25 mm can be held without being stressed.

With such a structure, even if the splitting portion 13 is subjected to a temperature change, no stress is applied to the single-core optical fiber 12 split inside the splitting and fixing portion, and each optical fiber is not affected. The power of light passing through the fiber does not change. Further, since the four-core tape-shaped optical fiber 11 is fixed to the main body housing 16 with the elastic adhesive 17, even if the housing 16 expands and contracts due to the temperature change, the stress applied to the tape-shaped optical fiber 11 becomes very small. The power change of the light passing through each optical fiber is very small. Further, even if the housing 16 expands or contracts in the lengthwise direction, since each single-core optical fiber 12 is loosely held in the protective tube 14, no stress is generated.

Table 1 shows the results of measuring changes in optical power at temperatures of −10 ° C., + 25 ° C. (room temperature), and + 60 ° C., using the above-described split fixing structure shown in FIG. In Table 1, the optical power at 25 ° C. is P ₂₅ (dBm), and the difference between the optical powers P ₋₁₀ and P ₆₀ (dBm) at −10 ° C. and + 60 ° C. P ₋₁₀ −P It is shown _{P 25 (dB) - 25,} P 60. The optical fiber used was a 1.3 μm wavelength singing mode quartz optical fiber with a core diameter of 9 μm and an outer diameter of 125 μm. The light source was an LD with a wavelength of 1.3 μm and the light receiver was a PD. For comparison, Table 1 also shows the characteristics of the structure having the split fixed part having the structure shown in FIG.

[0018]

[Table 1] Unit: dB

As is clear from the results shown in Table 1, there is an improvement in that the change in optical power due to temperature change is reduced by almost two digits as compared with the conventional technique. On the other hand, the strength of the split fixing portion 13 against the external force was examined by conducting a compression test using a parallel plate, and it was found that the conventional structure shown in FIG. 4 had a maximum load of 3.5 dB at a load of 0.1 kg. In contrast to the change in the optical power, the change in the optical power was 0.1 dB or less in this structure, which was very small even when adding up to 5 kg.

The multi-fiber optical fiber splitting and fixing device of the present invention is not limited to the 4-fiber optical fiber described in the embodiment, but can be changed to 2-fiber by changing the dimensions A and B of the protective member shown in FIG. It is obvious that the above multi-core optical fiber can also be applied.

[0021]

[Effect of device]

 As described above, the split fixed structure of the multi-fiber optical fiber of the present invention has a very small change in optical power even when the environmental temperature changes, and is strong against external force. In optical fiber communication systems for subscribers, where optical fibers are often used, they are installed on telephone poles or in manholes, and when used as an optical fiber splitting unit that distributes single-core optical fiber to each home, temperature changes in the outdoor environment and unexpected There is an advantage that an optical signal with stable power can be supplied even if external force is applied due to the disaster.

[Brief description of drawings]

FIG. 1 is a schematic view of a split fixing unit according to the present embodiment.

FIG. 2 is a perspective view thereof.

FIG. 3 is a perspective view of a housing according to the present embodiment.

FIG. 4 is a perspective view of a split fixing portion according to a conventional technique.

[Explanation of symbols]

 11 multi-core optical fiber 12 single-core optical fiber 13 division part 14 protection tube 15 accommodating part 16 housing 17 elastic adhesive 18 lid

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tomoyo Shibasaki 1-27-1 Kichijoji Minamimachi, Musashino City, Tokyo NTT Advanced Advance Technology Co., Ltd. (72) Inventor, Yukiko Imanoya Musashino City, Tokyo 1-27-1 Kichijoji Minamimachi NTT Advanced Technology Co., Ltd. (72) Creator Teruo Matsuyama 1-27-1 Kichijoji Minamimachi, Musashino-shi, Tokyo NTT Advanced Technology Co., Ltd. (72) Inventor Kaori Ishizu 1-27-1, Kichijoji-Minamicho, Musashino-shi, Tokyo NTT Advanced Technology Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. In a fixed structure of a split part for protecting a split part obtained by splitting a multi-fiber optical fiber into a single-core state, a housing part for housing and protecting the split part of the multi-fiber optical fiber, and a split part. A protective tube for protecting each of the subsequent single-core optical fibers, a multi-core optical fiber after the division and a single-core optical fiber protected by the protective tube are fixed respectively at the openings at both ends of the housing, and rubber is used after curing. A multi-fiber optical fiber splitting part fixing structure, characterized in that the structure comprises an elastic adhesive material having elasticity.