JP2020194065A - Optical fiber ribbon and optical fiber cable - Google Patents

Abstract

To provide an optical fiber ribbon and optical fiber cable that can suppress an increase in transmission loss in a low temperature environment.SOLUTION: In an optical fiber ribbon 1 having a plurality of coated optical fibers 11A to 11L arranged in parallel with and apart from each other and a connection resin 21 connecting the plurality of coated optical fibers 11A to 11L, a bridge portion 21a is provided that is formed by the connection resin 21 between adjacent coated optical fibers 11A to 11L, an outer diameter of the coated optical fibers 11A to 11L is 220 μm or less, a center-to-center distance between the adjacent coated optical fibers 11A to 11L is 250±30 μm, and the connection resin 21 has a Young's modulus of 0.5 to 200 MPa at normal temperature.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to fiber optic tape cores and fiber optic cables.

Patent Document 1 describes an optical fiber having a configuration in which a connecting portion formed of a resin is provided between adjacent single-core coated optical fibers with respect to a plurality of single-core coated optical fibers arranged apart from each other so as not to come into contact with each other. The tape core wire is described.
In Patent Document 2, a plurality of optical fiber core wires having an outer diameter of about 200 μm are arranged in parallel, and the cores of adjacent optical fiber core wires are collectively coated with resin so that the pitch is, for example, about 250 μm. It is stated that. Further, the document describes a method of manufacturing an intermittently connected optical fiber tape core wire by performing intermittent processing in which the resin is intermittently cut.
Patent Document 3 describes an intermittently connected optical fiber tape core wire in which the outer diameter dimension of the optical fiber core wire is 220 μm or less and the distance between the centers of adjacent optical fiber core wires is 250 ± 30 μm. ..

JP-A-2010-117592 JP-A-2015-52704 Japanese Unexamined Patent Publication No. 2013-88617

When the optical fiber core wires are arranged without gaps using the optical fiber core wires having a small diameter of 220 μm or less in the optical fiber tape core wires, the distance between the centers of the adjacent optical fiber core wires becomes short, and the existing fusion splicer It is difficult for the optical fiber core wire to be placed in the V-groove.

Patent Documents 2 and 3 describe intermittently connected optical fiber tape core wires having a distance between the centers of the optical fiber core wires of about 250 μm by leaving a gap between adjacent optical fiber core wires having a small diameter of 220 μm or less. Are listed. However, in the intermittently connected optical fiber tape core wire using the above-mentioned small-diameter optical fiber core wire, the gap between the optical fiber core wires is made constant, and intermittent processing is performed at high speed and with high accuracy in the longitudinal direction. It may be difficult to manufacture.

On the other hand, the optical fiber tape core wires that are not intermittently connected are arranged apart so that the optical fiber core wires do not come into contact with each other, as in the case of the optical fiber tape core wires described in Patent Document 1, for example. If the connecting portion is provided with a resin between the wires, the gap between the optical fiber core wires can be kept constant and connected. However, in the configuration as in Patent Document 1, when an optical fiber core wire having a small diameter of 220 μm or less is used, the rigidity of the optical fiber tape core wire may decrease, and the optical fiber tape core in the longitudinal direction due to temperature shrinkage. The wire may easily buckle. Therefore, it is conceivable that the transmission loss will increase in a low temperature environment.

An object of the present disclosure is to produce an optical fiber tape core wire and an optical fiber cable using a small diameter optical fiber core wire with high productivity, and to suppress an increase in transmission loss in a low temperature environment.

The optical fiber tape core wire according to one aspect of the present disclosure is
An optical fiber tape core wire having a plurality of optical fiber core wires arranged in parallel in a state of being separated from each other and a connecting resin for connecting the plurality of optical fiber core wires.
It has a bridge portion formed of the connecting resin between adjacent optical fiber core wires, and has a bridge portion.
The outer diameter of the optical fiber core wire is 220 μm or less.
The distance between the centers of the adjacent optical fiber core wires is 250 μm ± 30 μm.
The connecting resin has a Young's modulus of 0.5 MPa or more and 200 MPa or less at room temperature.

Further, the optical fiber cable according to one aspect of the present disclosure is
A slot-type optical fiber cable having a slot rod provided with a slot groove and the above-mentioned optical fiber tape core wire.
The optical fiber tape core wire is mounted in the slot groove,
The mounting density calculated from the cross-sectional area of the optical fiber tape core wire in the slot groove and the cross-sectional area of the slot groove is 25% or more and 65% or less.

According to the present disclosure, an optical fiber tape core wire and an optical fiber cable using a small diameter optical fiber core wire can be manufactured with high productivity, and an increase in transmission loss in a low temperature environment can be suppressed.

It is sectional drawing which shows an example of the optical fiber tape core wire which concerns on this embodiment. It is sectional drawing which shows an example of the optical fiber cable which concerns on this embodiment. It is a graph which shows the relationship between the deformation parameter of the optical fiber tape core wire shown in FIG. 1 and the transmission loss in a low temperature environment.

(Explanation of Embodiments of the present disclosure)
First, embodiments of the present disclosure will be listed and described.
The optical fiber tape core wire according to one aspect of the present disclosure is
(1) An optical fiber tape core wire having a plurality of optical fiber core wires arranged in parallel in a state of being separated from each other and a connecting resin for connecting the plurality of optical fiber core wires.
It has a bridge portion formed of the connecting resin between adjacent optical fiber core wires, and has a bridge portion.
The outer diameter of the optical fiber core wire is 220 μm or less.
The distance between the centers of the adjacent optical fiber core wires is 250 μm ± 30 μm.
The connecting resin has a Young's modulus of 0.5 MPa or more and 200 MPa or less at room temperature.
In the above optical fiber tape core wire, a plurality of optical fiber core wires having an outer diameter of 220 μm or less are used, and a bridge portion formed of a connecting resin is provided between the adjacent optical fiber core wires, and the adjacent optical fiber core wires are provided. The center-to-center distance is 250 μm ± 30 μm. By setting the Young's modulus of the connecting resin in the range of 0.5 MPa or more and 200 MPa or less in the optical fiber tape core wire having the above configuration, the rigidity of the optical fiber tape core wire becomes an appropriate range. As a result, since the optical fiber tape core wire has an appropriately high rigidity, buckling in the longitudinal direction due to temperature shrinkage is unlikely to occur, and an increase in transmission loss in a low temperature environment can be suppressed.

(2) The maximum thickness D of the optical fiber tape core wire including the optical fiber core wire is 235 μm or less.
Assuming that the width of the bridge portion is W, the thickness of the bridge portion is t, and the room temperature Young's modulus of the connecting resin is E, the deformation parameter P represented by P = D × E × t ² / W is 0.035 or more 14 It may be less than or equal to 2.
Since the deformation parameter P of the optical fiber tape core wire is 0.035 or more and 14.2 or less, appropriate rigidity can be obtained. Since the optical fiber tape core wire has an appropriately high rigidity, it is difficult to buckle in the longitudinal direction due to temperature shrinkage. Further, since the optical fiber tape core wire is not too rigid, when the optical fiber cable accommodating the optical fiber tape core wire is bent, the optical fiber tape core wire appropriately intersects in the width direction. Since it is deformed, an increase in transmission loss can be suppressed. Therefore, the optical fiber tape core wire can further suppress an increase in transmission loss in a low temperature environment.

(3) The optical fiber tape core wire may have 12 or more optical fiber core wires.
In a multi-core optical fiber tape core wire having 12 or more optical fiber cores, an increase in transmission loss in a low temperature environment can be suppressed.

(4) The connecting resin may be a resin containing silicon.
Since the above-mentioned connecting resin is a resin containing silicon, the coefficient of friction can be reduced. Since the friction coefficient of the connecting resin is small, when the plurality of optical fiber tape core wires are accommodated in the optical fiber cable and the temperature is lowered, each optical fiber tape core wire easily moves in the longitudinal direction. Therefore, the optical fiber cable accommodating the plurality of optical fiber tape core wires can further suppress the increase in transmission loss in a low temperature environment.

(5) The optical fiber core wire has a glass fiber and a coating that covers the outer periphery of the glass fiber.
The coating comprises two coating layers.
The outer coating layer of the two coating layers is
A base resin containing a urethane acrylate oligomer or urethane methacrylate oligomer, a monomer having a phenoxy group, a photopolymerization initiator and a silane coupling agent,
A cured product of a resin composition containing hydrophobic inorganic oxide particles.
The content of the inorganic oxide particles in the resin composition may be 1% by mass or more and 45% by mass or less based on the total amount of the resin composition.
By using the cured product of the above resin composition as the outer coating layer constituting the coating on the optical fiber core wire, the lateral pressure resistance of the optical fiber core wire is enhanced. If the optical fiber tape core wire is configured by using such an optical fiber core wire, it is possible to suppress an increase in transmission loss when the optical fiber tape core wire is housed in the optical fiber cable. It can be accommodated in high density.

Further, the optical fiber cable according to one aspect of the present disclosure is
(6) A slot-type optical fiber cable having a slot rod provided with a slot groove and the optical fiber tape core wire according to any one of (1) to (5) above.
The optical fiber tape core wire is mounted in the slot groove,
The mounting density calculated from the cross-sectional area of the optical fiber tape core wire in the slot groove and the cross-sectional area of the slot groove is 25% or more and 65% or less.
In a high-density optical fiber cable having an optical fiber tape core wire mounting density of 25% or more and 65% or less, an increase in transmission loss in a low temperature environment can be suppressed.

(Details of Embodiments of the present disclosure)
Specific examples of the optical fiber tape core wire and the optical fiber cable according to the embodiment of the present disclosure will be described below with reference to the drawings.
It should be noted that the present invention is not limited to these examples, and is indicated by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

FIG. 1 is a cross-sectional view showing an example of an optical fiber tape core wire according to an embodiment.
As shown in FIG. 1, in the optical fiber tape core wire 1 of this example, a plurality of (12 cores in this example) optical fiber core wires 11 (11A to 11L in this example) are arranged in parallel. The 12-core optical fiber core wires 11A to 11L are arranged with adjacent optical fiber core wires at a certain distance from each other, and are collectively connected by a connecting resin 21.

The optical fiber core wire 11 has, for example, a glass fiber 12 composed of a core and a clad, and two coating layers 13 and 14 that cover the periphery of the glass fiber 12. The inner coating layer 13 of the two coating layers is formed of a cured product of the primary resin. Further, the outer coating layer 14 of the two coating layers is formed of a cured product of the secondary resin.

A soft resin having a relatively low Young's modulus is used as the buffer layer for the cured product of the primary resin constituting the inner coating layer 13 in contact with the glass fiber 12. Further, as a cured product of the secondary resin constituting the outer coating layer 14, a hard resin having a relatively high Young's modulus is used as a protective layer. The cured product of the secondary resin has, for example, a Young's modulus at 23 ° C. of 900 MPa or more, preferably 1000 MPa or more, and more preferably 1500 MPa or more.

The secondary resin constituting the coating layer 14 includes a base resin containing a urethane acrylate oligomer or a urethane methacrylate oligomer, a monomer having a phenoxy group, a photopolymerization initiator and a silane coupling agent, and a hydrophobic inorganic oxide. It may be a resin composition containing particles. The content of the inorganic oxide particles in the resin composition is, for example, 1% by mass or more and 45% by mass or less based on the total amount of the resin composition.

Hereinafter, acrylate or the corresponding methacrylate is referred to as (meth) acrylate.

As the urethane (meth) acrylate oligomer, an oligomer obtained by reacting a polyol compound, a polyisocyanate compound, and a hydroxyl group-containing (meth) acrylate compound can be used. This oligomer can be obtained, for example, by reacting polypropylene glycol, isophorone diisocyanate, hydroxyethyl acrylate and methanol having a molecular weight of 4000.

As the monomer having a phenoxy group, a (meth) acrylate compound having a phenoxy group can be used. For example, the monomer having a phenoxy group is nonylphenol EO-modified acrylate (trade name "Aronix M-113" of Toagosei Co., Ltd.).

As the photopolymerization initiator, it can be appropriately selected from known radical photopolymerization initiators and used. For example, the photopolymerization initiator is 2,4,6-trimethylbenzoyldiphenylphosphine oxide or the like.

The silane coupling agent is not particularly limited as long as it does not interfere with the curing of the resin composition. For example, the silane coupling agent is 3-mercaptopropyltrimethoxysilane or the like.

Hydrophobic inorganic oxide particles have a hydrophobic group introduced on the surface of the inorganic oxide particles. The inorganic oxide particles are, for example, silica particles. The hydrophobic group may be a reactive group such as a (meth) acryloyl group or a vinyl group, or a non-reactive group such as a hydrocarbon group (for example, an alkyl group) or an aryl group (for example, a phenyl group). Good.

By blending the inorganic oxide particles with the secondary resin constituting the coating layer 14, the lateral pressure characteristic of the optical fiber core wire 11 is improved. The primary resin and the secondary resin constituting the coating layer 13 are formed of, for example, an ultraviolet curable resin, a thermosetting resin, or the like. The optical fiber core wire 11 has a bending loss of 0.25 dB / 10 turns or less when the bending radius R = 15 mm.

The connecting resin 21 is provided between the two optical fiber core wires so as to fill the gap between the adjacent optical fiber core wires, and is provided around the optical fiber core wire 11 so as to cover the optical fiber core wire 11. ing. The connecting resin 21 provided between the optical fiber cores constitutes a bridge portion 21a that bridges the adjacent optical fiber cores 11. Further, the connecting resin 21 provided around the optical fiber core wire 11 other than between the optical fiber core wires constitutes an outer peripheral covering portion 21b that covers the outer periphery of the optical fiber core wire 11. The optical fiber tape core wire 1 is a bridge-type optical fiber tape core wire having a bridge-shaped connecting portion between adjacent optical fiber core wires.

The Young's modulus E of the connecting resin 21 (bridge portion 21a and outer peripheral coating portion 21b) is 0.5 MPa or more and 200 MPa or less at room temperature (for example, 23 ° C.). Further, the connecting resin 21 may be formed of a resin containing silicon in order to suppress friction with other members arranged around the connecting resin 21.

In this example shown in FIG. 1, the thickness t of the bridge portion 21a (thickness in the direction orthogonal to the parallel direction of the optical fiber core wire) is the outer diameter R of the optical fiber core wire 11 and the thickness s of the outer peripheral covering portion 21b. Is thinner than the sum of. Therefore, a recess 22 formed by the bridge portion 21a is provided between the two adjacent optical fiber core wires 11. The recesses 22 are provided on both sides (upper side surface and lower side surface in FIG. 1) of the optical fiber tape core wire 1.

The distance F between the centers of the adjacent optical fiber cores in the optical fiber cores 11A to 11L is the outer diameter R of the optical fiber core 11 and the width W of the bridge portion 21a (the same direction as the parallel direction of the optical fiber cores). Width) and the sum of the lengths.

In the optical fiber tape core wire 1 configured as described above, the outer diameter R of the optical fiber core wires 11 (11A to 11L) is 220 μm or less. The distance F between the centers of the optical fiber core wires 11 is 250 ± 30 μm.

As shown in FIG. 1, the maximum thickness D of the optical fiber tape core wire 1 is, in this example, the outer diameter R of the optical fiber core wire 11 and the thickness s of the upper and lower outer peripheral covering portions 21b of the optical fiber core wire 11. The added thickness. The bridge width W is the width W of the bridge portion 21a, which is the distance between the outer circumferences of the adjacent optical fiber core wires 11.

The present inventors considered the deformation parameter P as an index indicating the deformability of the optical fiber tape core wire. The deformation parameter P is represented by the following equation (1) by the maximum thickness D of the optical fiber tape core wire 1, the width W of the bridge portion 21a, the thickness t of the bridge portion 21a, and the Young's modulus E of the connecting resin 21. ..
P = D × E × t ² / W equation (1)
The above-mentioned deformation parameter P is an index that the larger the value is, the less easily the optical fiber tape core wire 1 is deformed, and the smaller the value is, the more easily the optical fiber tape core wire 1 is deformed. The value of P in the optical fiber tape core wire 1 is, for example, 0.035 or more and 14.2 or less.

In the example shown in FIG. 1, the number of optical fiber cores in the optical fiber tape core is 12, but the number is not limited to this. The number of optical fiber cores may be 12 or more.
Further, the connecting resin 21 may be provided at least between the adjacent optical fiber core wires. That is, at least the bridge portion 21a may be provided, and the outer peripheral covering portion 21b may not be provided. Further, the outer peripheral covering portion 21b may be provided on only one side (upper side surface or lower side surface in FIG. 1) of the optical fiber tape core wire 1.
In the case where the outer peripheral covering portion 21b is not provided, the maximum thickness D of the optical fiber tape core wire 1 is equal to the outer diameter R of the optical fiber core wire 11. In the case where the outer peripheral covering portion 21b is provided on only one side of the optical fiber tape core wire 1, the maximum thickness D of the optical fiber tape core wire 1 is the outer diameter R of the optical fiber core wire 11 and the optical fiber core wire 1. The thickness is obtained by adding only the thickness s of the outer peripheral covering portion 21b on the upper side surface or the lower side surface of 11.

By the way, when optical fiber core wires having a diameter of 220 μm or less are arranged in parallel without gaps in the optical fiber tape core wires, the distance between the centers of the adjacent optical fiber core wires becomes short, and light is applied to the V groove of the existing fusion splicer. It is difficult to mount the fiber core wire. Therefore, for example, if the optical fiber core wires are arranged apart from each other so as not to come into contact with each other and a connecting portion is provided between the optical fiber core wires with a resin, that is, a bridge type optical fiber tape core wire is formed, they are adjacent to each other. The distance between the centers of the optical fiber core wires can be set to a predetermined distance for connection. However, in the configuration in which the connecting portion formed of resin is provided between the optical fiber core wires, the rigidity of the optical fiber tape core wire becomes low, and when the optical fiber tape core wire is placed in a low temperature environment, the temperature shrinks in the longitudinal direction of the optical fiber tape core wire. Easy to buckle. Therefore, the transmission loss tends to increase in a low temperature environment.

On the other hand, in the optical fiber tape core wire 1 according to the above embodiment, since the Young's modulus of the connecting resin 21 is in the range of 0.5 MPa or more and 200 MPa or less, the rigidity of the optical fiber tape core wire 1 is in an appropriate range. It has become. The optical fiber tape core wire 1 uses an optical fiber core wire having an outer diameter R of 220 μm or less, and is provided with a bridge portion 21a formed of a connecting resin 21 between adjacent optical fiber core wires 11. Even if the center-to-center distance F is 250 ± 30 μm, buckling in the longitudinal direction due to temperature shrinkage is unlikely to occur because the rigidity is moderately large. As a result, the optical fiber tape core wire 1 can suppress an increase in transmission loss in a low temperature environment.

Further, if the deformation parameter P of the optical fiber tape core wire 1 is 0.035 or more and 14.2 or less, more appropriate rigidity can be obtained. Since the optical fiber tape core wire 1 is not too rigid, the optical fiber tape core wire 1 is appropriately deformed in the width direction when the optical fiber cable accommodating the optical fiber tape core wire 1 is bent, so that the optical fiber tape core wire 1 is transmitted. The increase in loss is suppressed. Therefore, the optical fiber tape core wire 1 can further suppress an increase in transmission loss in a low temperature environment.

Further, if the connecting resin 21 of the optical fiber tape core wire 1 contains silicon, the friction coefficient of the connecting resin 21 is smaller than that of the resin containing no silicon. Therefore, for example, when a plurality of optical fiber tape core wires 1 are accommodated in the optical fiber cable and the temperature is lowered, each optical fiber tape core wire 1 has a small frictional force with other members arranged around it. Easy to move in the longitudinal direction. Therefore, when the optical fiber tape core wire 1 is housed in the optical fiber cable, it is possible to suppress an increase in transmission loss in a low temperature environment.

Further, if a cured product of the above resin composition (resin containing inorganic oxide particles) is used as the outer coating layer 14 constituting the coating of the optical fiber core wire 11, the lateral pressure resistance of the optical fiber core wire 11 can be improved. Can be strong. If the optical fiber tape core wire 1 is configured by using such an optical fiber core wire 11, it is possible to suppress an increase in transmission loss when the optical fiber tape core wire 1 is accommodated in the optical fiber cable. As a result, the optical fiber tape core wire 1 can be accommodated in the optical fiber cable at a high density.

Next, the optical fiber cable according to the present embodiment will be described with reference to FIG. FIG. 2 is a diagram showing an example of a slot-type optical fiber cable using the optical fiber tape core wire 1 according to the present embodiment.

The slot-type optical fiber cable 30 shown in FIG. 2 includes a slot rod 32 having a plurality of (six in this example) slot grooves 31, a plurality of optical fiber tape core wires 1 housed in the slot grooves 31, and a plurality of optical fiber tape core wires 1. It has. In FIG. 2, in order to explain the inside of the slot groove 31, for convenience, one slot groove 31 is enlarged and its internal configuration is illustrated. Since the internal configuration of each slot groove 31 is the same, the other five slot grooves 31 are hatched and the internal configuration is omitted.

The slot rod 32 has a tension member 33 in the center, and has a structure in which a plurality of (six in this example) slot grooves 31 are provided radially. Each optical fiber tape core wire 1 is laminated and mounted in the slot groove 31. In the example of FIG. 2, the optical fiber tape core wires 1 are laminated in the same direction, but they may be laminated in the same direction. A presser foot tape 34 is wound around the slot rod 32, and a jacket 35 is formed around the presser foot tape 34.

In the optical fiber cable 30, the mounting density of the optical fiber tape core wire 1 in each slot groove 31 is 25% or more and 65% or less. The mounting density of the optical fiber tape core wire 1 means the ratio of the cross-sectional area of the optical fiber tape core wire 1 mounted in each slot groove 31 to the cross-sectional area of each slot groove 31. For example, the slot-type optical fiber cable 30 shown in FIG. 2 is a 3456-core cable in which 48 optical fiber tape core wires 1 are mounted in each slot groove 31, and the outer diameter of the optical fiber cable 30 is 34 mm. When manufactured, the optical fiber tape core wire 1 can be accommodated at a mounting density of 50%.

The optical fiber cable 30 is mounted with an optical fiber tape core wire 1 having the above-described configuration. However, even with the optical fiber tape core wire 1 having the above-described configuration, when the mounting density of the optical fiber tape core wire 1 exceeds 65%, the ratio of the optical fiber tape core wire 1 in which the transmission loss increases is large. Become. On the other hand, if the mounting density of the optical fiber tape core wire 1 is less than 25%, it is difficult to increase the density. On the other hand, according to the optical fiber cable 30, since the mounting density of the optical fiber tape core wire 1 is 25% or more and 65% or less, a low temperature environment is realized while achieving high density. The increase in transmission loss underneath can be suppressed.

(Example)
In the optical fiber tape core wire 1 according to the present embodiment, the sample No. 1 is set so that the deformation parameter P is different by changing the maximum thickness D, the bridge thickness t, and the Young's modulus E of the optical fiber tape core wire. 1-27 were prepared. Sample No. The outer diameter R of the optical fiber core wires 11 of 1 to 27 is 220 μm or less. In addition, sample No. Silicon is contained in the connecting resins 1 to 27. Further, in this embodiment, the bridge width W is set so that the value obtained by adding the maximum thickness D of the optical fiber tape core wire 1 and the bridge width W in each sample is 270 μm. In addition, the above sample No. Nos. 1 to 27 are those in which the secondary resin of the optical fiber core wire 11 does not contain inorganic oxide particles.
In this example, each sample was evaluated for transmission loss in a low temperature (-40 ° C) environment. Table 1 below shows sample numbers. The evaluation results of the transmission loss for 1 to 27 are shown.

For the evaluation of each sample, the optical fiber tape core wire of the sample was housed in the optical fiber cable 30 shown in FIG. 2 so as to have a mounting density of 50%, and the optical fiber cable was placed in a low temperature (-40 ° C.) environment. At that time, it was judged whether or not the wavelength of the signal light was 1.55 μm and the transmission loss satisfied 0.5 dB / km or less. If the transmission loss is 0.5 dB / km or less, it is judged that the transmission loss is good, and if the transmission loss is larger than 0.3 dB / km and 0.5 dB / km or less is evaluated B, the transmission loss is 0. The evaluation A was 3 dB / km or less. Further, if the transmission loss exceeds 0.5 dB / km, it is judged that the transmission loss is inferior and evaluated as C. That is, the sample of evaluation A or evaluation B is an optical fiber tape core wire having good transmission loss characteristics.

The relationship between the deformation parameter P of each sample shown in Table 1 and the transmission loss in an environment of −40 ° C. is shown in FIG. 3 as a graph of transmission loss characteristics in a low temperature environment. In FIG. 3, the region below the broken line L1 is the region where the evaluation of the transmission loss is A, and the region between the broken line L1 and the broken line L2 is the region where the evaluation of the transmission loss is B. Further, the region above the broken line L2 is the region where the evaluation of transmission loss is C.

According to the evaluation results in Table 1, the samples with good transmission loss (samples in evaluation A or evaluation B) are No. It was 1-27. Among them, the sample having a particularly good transmission loss (sample of evaluation A) is No. 4-9, No. 12-18, No. It was 21-26. As a result, it was found that the transmission loss of the optical fiber tape core wire 1 is particularly good when the deformation parameter P is 0.035 or more and 14.2 or less.

Further, if the deformation parameter P is too small (less than 0.035), the rigidity of the optical fiber tape core wire 1 becomes small, and the optical fiber tape core wire buckles when the optical fiber cable contracts in a low temperature environment. It was found that the transmission loss increased due to the occurrence of. On the other hand, if the deformation parameter P is too large (more than 14.2), the rigidity of the optical fiber tape core wire 1 becomes large. For example, when the optical fiber cable is drum-wound and bent, the optical fiber tape core wire 1 becomes It was found that the transmission loss increases because the light is less likely to be deformed in the direction intersecting the width direction.

When increasing the core density of the optical fiber tape core wire mounted on the optical fiber cable, it is desirable that the maximum thickness D of the optical fiber tape core wire 1 is 235 μm or less.

Further, in order to further improve the transmission loss, the secondary resin of the optical fiber core wire 11 was examined. Therefore, the sample No. A sample in which the optical fiber core wire 11 has the same configuration as that of No. 1 and is changed to a secondary resin containing inorganic oxide particles is separately prepared, and the sample No. The transmission loss in a low temperature (-40 ° C) environment was evaluated in the same manner as in 1-27. As a result, the transmission loss of 0.5 dB / km (Sample No. 1) in the transmission loss under the environment of −40 ° C. in Table 1 could be reduced to 0.3 dB / km.
Sample No. The transmission loss of No. 1 is No. Since it is the largest among 1 to 27, when inorganic oxide particles are mixed with the secondary resin, No. The transmission loss is 0.3 dB / km or less for all the samples 1 to 27.

Further, if the connecting resin 21 of the optical fiber tape core wire 1 contains silicon, the friction coefficient of the connecting resin 21 is smaller than that of the resin containing no silicon. Therefore, in a low temperature environment, each optical fiber tape core wire 1 has a small frictional force with other members arranged around it, so that it can easily move in the longitudinal direction.
In order to verify that the transmission loss characteristics in a low temperature environment are improved by containing silicon in the connecting resin, a sample in which the connecting resin 21 is changed to a connecting resin to which silicon is not added is separately prepared, and the sample No. .. The transmission loss in a low temperature (-40 ° C) environment was evaluated in the same manner as in 1-27. According to the evaluation, the sample changed to the connecting resin to which silicon was not added was the sample No. to which silicon was added. The transmission loss in a low temperature environment increased by about 1.5 times as compared with 1-27. That is, it was found that when silicon was added to the connecting resin, the transmission loss characteristics in a low temperature environment were improved and the transmission loss could be suppressed to about 2/3 as compared with the case where silicon was not added.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. Further, the number, position, shape and the like of the constituent members described above are not limited to the above-described embodiment, and can be changed to a number, position, shape and the like suitable for carrying out the present invention.

1: Optical fiber tape core wire 11 (11A to 11L): Optical fiber core wire 12: Glass fiber 13: Inner coating layer 14: Outer coating layer 21: Connecting resin 21a: Bridge portion 21b: Outer peripheral coating portion 22: Recess 30: Optical fiber cable 31: Slot groove 32: Slot rod

Claims (6)

An optical fiber tape core wire having a plurality of optical fiber core wires arranged in parallel in a state of being separated from each other and a connecting resin for connecting the plurality of optical fiber core wires.
It has a bridge portion formed of the connecting resin between adjacent optical fiber core wires, and has a bridge portion.
The outer diameter of the optical fiber core wire is 220 μm or less.
The distance between the centers of the adjacent optical fiber core wires is 250 μm ± 30 μm.
The connecting resin has a Young's modulus of 0.5 MPa or more and 200 MPa or less at room temperature.
Fiber optic tape core wire. The maximum thickness D of the optical fiber tape core wire including the optical fiber core wire is 235 μm or less.
Assuming that the width of the bridge portion is W, the thickness of the bridge portion is t, and the room temperature Young's modulus of the connecting resin is E, the deformation parameter P represented by P = D × E × t ² / W is 0.035 or more 14 .2 or less,
The optical fiber tape core wire according to claim 1. The optical fiber tape core has 12 or more optical fiber cores.
The optical fiber tape core wire according to claim 1 or 2. The connecting resin is a resin containing silicon.
The optical fiber tape core wire according to any one of claims 1 to 3. The optical fiber core wire has a glass fiber and a coating that covers the outer periphery of the glass fiber.
The coating comprises two coating layers.
The outer coating layer of the two coating layers is
A base resin containing a urethane acrylate oligomer or urethane methacrylate oligomer, a monomer having a phenoxy group, a photopolymerization initiator and a silane coupling agent,
A cured product of a resin composition containing hydrophobic inorganic oxide particles.
The content of the inorganic oxide particles in the resin composition is 1% by mass or more and 45% by mass or less based on the total amount of the resin composition.
The optical fiber tape core wire according to any one of claims 1 to 4. A slot-type optical fiber cable having a slot rod provided with a slot groove and an optical fiber tape core wire according to any one of claims 1 to 5.
The optical fiber tape core wire is mounted in the slot groove,
The mounting density calculated from the cross-sectional area of the optical fiber tape core wire in the slot groove and the cross-sectional area of the slot groove is 25% or more and 65% or less.
Fiber optic cable.

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