JP2010256467A - Optical fiber drop cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drop cable which has functions of reference of a coated optical fiber and detection of failure without necessitating the connection of optical fibers, and transforms the optical fiber into an indoor cable having a common line characteristic. <P>SOLUTION: The optical fiber drop cable is provided with: an inner layer cable 11, comprising at least one optical fiber 3, a pair of tensile strength bodies 5 arranged on the both sides of the optical fiber 3 on a straight line which passes through the center of the optical fiber 3 parallel to one of two directions orthogonal to the longitudinal direction of the optical fiber 3, and an inner layer covering 7 formed of a non-black resin having a friction coefficient of 0.10 to 0.40 and durometer hardness (HDD) of 55 to 70 with which the circumferences of the optical fiber 3 and the tensile strength bodies 5 are covered integrally; and an outer layer covering 13 formed of a resin having a friction coefficient of 0.40 to 2.00 and a durometer hardness (HDD) of 36 to 53 with which the outer circumference of the inner layer covering 7 is covered. The optical fiber drop cable has a dual layer structure in which the inner layer covering 7 and the outer layer covering 13 are not fused to each other, but can be separated from each other, while the inner layer cable 11 functions as an indoor cable. The surfaces of the inner layer and the outer layer coverings 7, 13 are notched. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical fiber drop cable, and more particularly, a small-core aerial optical fiber cable constructed between utility poles when an optical fiber composed of one or more optical fiber cores or the like is drawn into a small-scale building or a general household, The present invention relates to an optical fiber drop cable having an indoor cable for drawing into a scale building or a general home.

  Conventionally, FTTH (Fiber to the Home), that is, from an optical fiber cable of an access system extended from a telephone station to a building or general in order to be able to transmit and receive high-speed broadband information such as ultra-high-speed data at home or office For example, an optical fiber made of an optical fiber core or the like is pulled down to a subscriber's house such as a house, and an optical fiber drop cable is used for wiring the optical fiber. In other words, the optical fiber drop cable is used when drawing the optical fiber from the branch closure of the main line cable on the utility pole into the home, and is mainly applied to the optical fiber drop cable (outdoor line) and a longer installation span. For this purpose, a small-core optical aerial cable with an increased support line size is used. This cable has a self-supporting structure in which a support wire portion and a cable main body rod are connected via a neck portion.

  Further, optical fiber cables used in subscriber premises, buildings, condominiums, and the like do not have a support wire portion, and have a structure having only a cable body. The outer jacket is coated with a non-halogen flame retardant outer jacket.

  Referring to FIG. 7, as a conventional optical fiber drop cable 101, for example, an optical fiber 103 made of an optical fiber core or the like and a longitudinal direction of the optical fiber 103 (a direction orthogonal to the paper surface in FIG. 7). An aramid, for example, arranged to extend in the same direction as the longitudinal direction of the optical fiber 103 on both sides of the optical fiber 103 on a straight line that is parallel to one of two orthogonal directions and passes through the center of the optical fiber 103 A pair of strength members 105 made of fiber FRP and the like, and a high-strength resin having, for example, a rectangular cross-sectional shape and low friction and wear resistance covering the outer periphery of the optical fiber 103 and the pair of strength members 105 And an elongate optical element portion 109 made up of an outer cover 107 made up of.

  In the optical element portion 109, a notch portion 111 is formed on the surface of the jacket 107 above and below the optical fiber 103.

  The long optical element portion 109 and a jacket 117 made of a resin covering a support wire 115 made of, for example, steel wire on the left side of the optical element portion 109 in FIG. A long optical fiber drop cable 101 is constituted by the integrated support line portion 119.

  The outer cover 107 is made of a high-strength resin having low friction and wear resistance, so that measures are taken so that the laying tube does not pierce the outer cover 107.

  Further, as conventional optical fiber cables, there are those shown in Patent Documents 1 to 3.

Japanese Patent No. 4040633 JP 2004-205979 A JP 2004-272069 A

  At present, an optical fiber drop cable 101 (hereinafter simply referred to as a “drop cable”) pulled from a closure is directly pulled into a house through an air-conditioner duct or the like. Thereafter, it is connected to an optical fiber indoor cable (hereinafter simply referred to as “indoor cable”), or connected to the indoor cable in a cabinet installed on the wall of the house and the like, and similarly drawn to the ONU (terminating device).

  When the indoor cable is a single unit, outdoor wiring is not possible because the weather resistance and cold resistance of the jacket material are inferior to those of the jacket 107 of the drop cable 101. Therefore, in this case, the connection from the drop cable 101 to the indoor cable is essential, and a connection loss occurs at this connection location. Moreover, it is necessary to attach a connector for connection. Therefore, work time is required for attaching the connector.

  Moreover, since the drop cable 101 is black because carbon black is blended in the resin of the outer jacket 107 in order to impart weather resistance, the scenery at the time of laying is impaired. In addition, since the outer jacket 107 is black, light is absorbed, so that the cords cannot be contrasted by the ID tester like the indoor cable.

  Furthermore, in recent years, optical fiber disconnection damage due to spawning on the drop cable 101 due to kumazemi has frequently occurred, and it has been confirmed that damage cannot be suppressed with existing structures and resins. As a semi-measure, a method of coating the material of the jacket 107 with a high-hardness resin has been studied, but the high-hardness resin does not bite into the connector member when attaching the connector, and the pulling force from the connector can be secured. There is a problem that disappears.

  Furthermore, not only air-conditioner ducts, but also optical fiber cables used in subscriber premises, buildings, condominiums, and the like are often routed in electric wire pipes such as synthetic resin flexible pipes. However, many existing metal cables and optical cables are introduced into these pipes, and additional laying is difficult in a state where these cables almost occupy the inside of the pipe for electric wires. In order to perform additional laying in such a situation, it is effective that the jacket is a low friction cable. However, when the material of the cable jacket has low friction, the bundle collapses in a cable that is shipped and used in a bundled shape like a drop indoor.

  In Patent Document 1, a single-core optical fiber core, first and second strength members that are arranged in parallel at intervals on both sides of the single-core optical fiber, and a jacket that collectively covers them are provided. The outer jacket has a two-layer structure of an inner coating made of non-black resin and an outer coating made of black resin that can be peeled off from the inner coating. However, there is no description of the adhesion between the two layers of the inner coating and the outer coating. That is, if the adhesion between the two layers is high, there is a problem that the internal cable (inner coating) cannot be taken out. Further, the absence of this tightness regulation may cause a problem in the connector gripping characteristics.

  Moreover, the friction coefficients of the inner coating and the outer coating are not described, and the lineability and the bundling property are not taken into consideration. Moreover, since the hardness of an inner coating and an outer coating is not described, the anti-kumazemi property is not actively considered.

  In addition, since the notch provided in the outer coating is arranged so that the single-core optical fiber core and the first and second strength members are substantially straight and the notch position is different from the normal product, a general-purpose tool such as a detacher is used. Can not be torn with

  In Patent Document 2, the outer cover has a two-layer structure substantially similar to that of Patent Document 1, but there is no description of separating the inner layer and the outer layer, and there is no description of the adhesion between the two layers. That is, if the adhesion between the two layers is high, there is a problem that the internal cable (inner coating) cannot be taken out. Further, the absence of this tightness regulation may cause a problem in the connector gripping characteristics.

  In addition, the friction coefficients of the inner layer and the outer layer are not described, and the wiring property and the bundling property are not taken into consideration. Moreover, since the hardness of the inner layer and the outer layer is not described, the anti-kumazemi property is not actively considered. In addition, cord contrast, landscape and bundling characteristics are not considered.

  In Patent Document 3, the single-layer structure is the same as that in FIG. 7 and it is necessary to add carbon black in order to ensure weather resistance. Point detection is not possible. Further, since the outer sheath has a low coefficient of friction, the lineability is good. However, the bundle coefficient is not good because the bundle friction is caused by the described coefficient of friction. In addition, since the outer cover has a low coefficient of friction, slipping occurs when the outer cover is gripped, which causes a problem in the connector gripping characteristics. Moreover, if the diameter of the drop cable is simply reduced, matching with existing closures, cabinets, and connectors cannot be achieved.

  INDUSTRIAL APPLICABILITY This invention is an outdoor drop cable having weather resistance, cold resistance, and semi-resistance, and has a function of detecting a core line and detecting a fault point without requiring an optical fiber connection, and has a wiring property. The purpose is to make the cable changeable.

In order to solve the above-described problems, an optical fiber drop cable according to the present invention includes one or more optical fibers disposed in the center,
The optical fiber extends in the same direction as the longitudinal direction of the optical fiber on both sides of the optical fiber on a straight line that is parallel to one of the two directions orthogonal to the longitudinal direction of the optical fiber and passes through the center of the optical fiber. A pair of tensile bodies arranged;
The coefficient of friction that integrally covers the outer periphery of the optical fiber and the pair of strength members is 0.10 or more and 0.40 or less, and the durometer hardness (HDD) is 55 or more and less than 70. An inner layer jacket made of black resin,
An inner layer outer notch formed on the lower and upper surfaces of the inner outer layer that is parallel to the other of the two directions and passes through the center of the optical fiber, Inner layer cable,
An outer layer jacket made of a resin having a friction coefficient of 0.40 or more and 2.00 or less and a durometer hardness (HDD) of 36 to 53, which covers the outer periphery of the inner layer jacket of the inner layer cable;
An outer layer outer notch formed on the lower and upper surfaces of the outer jacket that is parallel to the other of the two directions and passes through the center of the optical fiber;
The inner layer jacket and the outer layer jacket are not fused and can be separated, and the inner layer cable constitutes a two-layer structure that functions as an indoor cable; and
A long support line portion in which a support line is covered with a cover is integrated in parallel with each other on the outer layer cover of the optical element portion.

  In the optical fiber drop cable according to the present invention, it is preferable that in the optical fiber drop cable, the inner layer outer notch portion and the outer layer outer notch portion are aligned in a line substantially passing through the optical fiber.

  In the optical fiber drop cable according to the present invention, it is preferable that a pulling force for pulling out the inner layer cable from the outer layer jacket is 30 N / 20 mm or more and 500 N / 20 mm or less.

  In the optical fiber drop cable of the present invention, it is preferable that the inner layer jacket is made of a polyolefin resin, and the outer layer jacket is made of a polyolefin resin or a polyurethane resin.

  Further, the optical fiber drop cable of the present invention is the optical fiber drop cable, wherein the outer layer jacket is made of a resin having a cold resistance with F (0) of −30 ° C. or less in an embrittlement test according to JIS K7216. It is preferable to become.

  As can be understood from the means for solving the problems as described above, according to the present invention, since the outer layer jacket and the inner layer jacket have a separable two-layer structure, the outer layer jacket is torn. Only the inner layer cable can be drawn into the house as an indoor cable. As a result, there is no need for connection with the indoor cable, so the work of attaching the connector is eliminated. Moreover, since the connection part between optical fibers reduces, the location where a connection loss occurs can be reduced.

  Moreover, since only the inner layer cable provided with the non-black inner layer jacket can be taken out, the inner wire of the inner layer cable can be contrasted and the failure point can be confirmed.

  Since the optical fiber is protected by the high-strength inner layer jacket having a durometer hardness (HDD) of 55 to 70, it is possible to avoid disconnection damage due to the kuma-zemi. A highly reliable cable with semi-resistance.

  In addition, since an inner layer cable having low friction and wear resistance characteristics is mounted and the inner layer cable can be easily taken out, the passage through the pipe is improved due to the small diameter and low friction. Thereby, workability is excellent and working time can be shortened. Moreover, since it is abrasion-resistant, the influence of the abrasion by another cable can be reduced.

  Moreover, since the friction coefficient of the outer envelope is 0.4 or more, operation in a bundled state is possible.

It is sectional drawing of the optical fiber drop cable of embodiment of this invention. It is a schematic explanatory drawing which shows the wiring state of the cable of FIG. It is a schematic explanatory drawing which shows the lead-out operation | work of the optical element part of the cable of FIG. FIG. 4 is a plan view of an optical fiber drop cable in which an inner layer cable is led out in FIG. 3. It is a schematic explanatory drawing which measures the pulling force which pulls out an inner layer cable from an outer layer jacket. It is a perspective view which shows the state of cable bundle winding. It is sectional drawing of the conventional optical fiber drop cable.

  Embodiments of the present invention will be described below with reference to the drawings.

  Referring to FIG. 1, an optical fiber drop cable 1 includes one or more optical fibers 3 including, for example, an optical fiber core disposed in the center, and a longitudinal direction of the optical fiber 3 (in FIG. 1 on both sides of the optical fiber 3 on a straight line (X axis) parallel to one direction (left and right direction in FIG. 1) of two directions orthogonal to the direction orthogonal to the optical fiber 3. For example, a pair of strength members 5 made of, for example, an aramid fiber FRP and the like stretched in the same direction as the longitudinal direction of the optical fiber 3, and the inner layer outside integrally coated on the outer periphery of the optical fiber 3 and the pair of strength members 5. Inner layer outer cover formed on the upper and lower surfaces of the inner layer outer cover 7 in a straight line (Y axis) parallel to the other direction out of the two directions and the center of the optical fiber 3. A notch 9 and a long length Inner cable 11 is configured.

  The inner layer jacket 7 is made of a non-black resin having a friction coefficient according to JIS K7125 of 0.10 or more and 0.40 or less, a durometer hardness (HDD) of 55 or more and less than 70. It is configured. For the resin of the inner layer jacket 7, for example, a polyolefin-based resin having low friction / flame retardant wear resistance is used.

  In addition, the outer-layer jacket 13 covering the outer periphery of the inner-layer jacket 7 of the inner-layer cable 11 is parallel to the other direction (vertical direction in FIG. 1) of the two directions and the optical fiber 3. The outer layer jacket notch 15 formed on the upper and lower surfaces of the outer layer jacket 13 in a straight line passing through the center of the outer layer jacket, and the inner layer jacket 7 and the outer layer jacket 13 are not fused and can be separated. The inner layer cable 11 constitutes an optical element portion 17 having a two-layer structure that functions as an indoor cable.

  The outer layer jacket 13 has a friction coefficient of 0.40 or more and 2.00 or less according to JIS K7125, a durometer hardness (HDD) of 36 to 53, and a brittleness according to JIS K7216. In the chemical conversion test, F (0) is made of a resin having cold resistance of −30 ° C. or lower. Said -30 degrees C or less considers the use in a cold region.

  Moreover, for example, a polyolefin resin having cold resistance and weather resistance is used as the resin of the outer layer jacket 13. However, it is possible to coat not only this polyolefin resin but also polyurethane resin. In addition, from the viewpoint that the outer layer jacket 13 and the inner layer jacket 7 are not fused, it is preferable to use a polyurethane-based resin that is hardly compatible with the polyolefin resin of the inner layer jacket 7 for the outer layer jacket 13.

  The long inner layer cable 11 separated from the outer layer jacket 13 has wear resistance that does not damage the metal cable or the cable, and further, the single body clears the JIS C3005 inclined combustion test. Is.

  In addition, a long support line portion 25 in which a support wire 21 made of, for example, a steel wire is covered with an outer cover 23 is integrated in parallel with each other through the neck portion 19 with the outer layer jacket 13. In this embodiment, the outer cover 23 is made of the same material as the outer layer cover 13.

  As described above, the inner layer jacket 7 and the outer layer jacket 13 are not fused in the longitudinal direction, and the pulling force for pulling the inner layer cable 11 from the outer layer jacket 13 is 30 N / 20 mm or more, and 500 N / 20 mm or less.

  Further, it is desirable that the inner layer outer notch portion 9 and the outer layer outer notch portion 15 are arranged in a line on the Y-axis line passing through the optical fiber 3. As a result, the two layers can be torn from the inner layer jacket notch portion 9 and the outer layer jacket notch portion 15 at a time, or either the outer layer jacket 13 alone, and the inner layer cable 11 as an optical fiber 3 or an indoor cable. Can be taken out. Further, since the inner layer jacket 7 of the inner layer cable 11 is made of a non-black resin, it is possible to contrast the cores with an ID tester.

  In this embodiment, the thickness of the inner layer jacket 7 up to the optical fiber 3 under the inner layer notch portion 9 is 0.3 mm.

  With the above configuration, as shown in FIG. 2, the optical fiber drop cable 1 is partially cut off at the neck 19 at the end to separate the outer sheath 13 and the support wire 25, and this separated one The end portion 25A of the support line portion 25 is fixed to the outdoor line catching tool 29 of the utility pole 27, and the other end portion 25B is fixed to a part of the house via the catching tool 29.

  Then, one end portion 17A of the element portion 17 (the inner layer cable 11 and the outer layer jacket 13) is cut off to take out the optical fiber 3 from the inner layer cable 11, and the optical fiber 3 is connected to the branch closure 31 on the utility pole 27. Connected to. In the branch closure 31, an optical fiber (not shown) branched from the access-system optical fiber cable 33 on the utility pole 27 and the optical fiber 3 taken out from the end portion 17 </ b> A of the element portion 17 are connected.

  On the other hand, on the other end 17B side of the element portion 17, as shown in FIG. 3, the outer layer jacket 13 is moved from the outer layer jacket notch portion 15 with the tools 35A and 35B such as a detacher as shown in FIG. When tearing in the left-right direction, as shown in FIG. 4, the outer layer jacket 13 is separated from the inner layer jacket 7 (inner layer cable 11) and is torn. As it is, the outer layer jacket 13 is torn to expose the inner layer cable 11, and the torn outer layer jacket 13 is removed. In FIG. 4, the core line is contrasted by the ID tester T.

  As a result, as shown in FIG. 2, the inner layer cable 11 becomes an indoor cable and is wired indoors. Thereafter, the inner layer jacket 7 is cut off from the inner layer jacket notch portion 9 at the end of the inner layer cable 11 (indoor cable), and the optical fiber 3 is taken out from the inner layer jacket 7. OE converter or termination device 37 (ONU).

  Next, in order to show the effectiveness of the optical fiber drop cable 1 of this embodiment, the durometer hardness (HDD) (durometer hardness JIS K7215) of each resin of the inner layer jacket 7 and the outer layer jacket 13 is changed and tested. Table 1 shows the results of evaluation of the semi-proof characteristics, the connector gripping characteristics, and the detachability of the detacher for each test cable.

  The semi-resisting property is defined as ○ when the test cable with a combination of durometer hardness (HDD) shown in Table 1 is laid in West Japan for 100 m and the depth of the cicada spawning damage is 0.2 mm or less. The case where it was deeper than 2 mm was set as x.

  In addition, the connector gripping property was determined by checking whether or not the connector was dropped when a connector was attached to the end of the test cable and a 1 kg load was applied to the connector tip for 1 minute. The case where the dropout did not occur was marked with ◯, and the case where the dropout occurred was marked with ×.

Further, the lead-out property means that the cable terminal portion and the intermediate portion are torn with the tools 35A and 35B such as a detacher, and only the outer layer jacket 13 can be torn to take out the inner layer cable 11, and the inner layer jacket 7 and the outer layer jacket 13 can be taken out. The case where the inner layer cable 11 was torn and the inner optical fiber 3 could be taken out after tearing the outer layer sheath 13 was marked with ◯, and the case where the inner layer cable 11 and the optical fiber 3 could not be taken out was marked with x.

  As a result of the evaluation, as can be seen from Table 1, when the durometer hardness (HDD) of the inner shell 7 is 53 or less, the semi-resistant property is x. Further, when the durometer hardness (HDD) of the outer layer jacket 13 is 55 or more, the connector gripping characteristic is x. Further, all the mouth openability was good (◯), which was a result different from the conventional patent literature. This is due to the adhesion between the inner layer jacket 7 and the outer layer jacket 13.

  Next, when the adhesion between the inner layer jacket 7 and the outer layer jacket 13 of the optical fiber drop cable 1 of this embodiment was evaluated, the results shown in Table 2 were obtained.

  As shown in FIG. 5, as the evaluation method, the support cable portion 25 of the drop cable 1 is fixed with one chuck 39A, and the inner cable 11 led out from the outer jacket 13 is connected to the other chuck 39B. The adhesiveness was evaluated by a method of measuring the pulling force by gripping and pulling out with. Moreover, the presence or absence of the fusion | melting of the extracted inner layer cable 11 and the outer layer jacket 13 was confirmed visually. The change in adhesion was adjusted by the nipple back amount (spacing amount) from the die during extrusion molding.

The connector bending characteristics were also investigated. The connector bending characteristics were measured by measuring a fluctuation in loss when a jacketed connector was attached to the tip of the test cable, a load of 500 g was applied, and a bending test of ± 90 ° × 10 cyc was performed. When the loss fluctuation before and after the test was 0.2 dB or less, it was evaluated as ◯, and when it was larger than 0.2 dB, it was rated as x.

  As a result of the evaluation, as can be seen from Table 2, when the nipple back amount (spacing amount) is increased to increase the adhesion and exceed 500 N / 20 mm, the inner layer outer jacket 7 and the outer layer outer jacket 13 are fused. confirmed. Also, if the adhesion force is reduced to less than 30 N / 20 mm, it is confirmed that the inner layer cable 11 is drawn when the test cable is bent in the bending test after the connector is attached, and a loss fluctuation of 0.2 dB or more occurs. It was done.

  Next, when the influence of the friction coefficient of the outer sheath 13 of the optical fiber drop cable 1 of this embodiment was evaluated, it was as shown in Table 3.

  In addition, as the evaluation method, the friction coefficient of the outer envelope 13 was measured, and the bundle winding characteristics were evaluated. The reason for this is that if the friction coefficient of the outer sheath 13 is low, cable bundle breakage is likely to occur, and winding defects during manufacture also increase. On the other hand, if the friction coefficient is high and the cables do not slip, they cannot be bundled.

At this time, the friction coefficient of the outer layer jacket 13 was measured in accordance with JIS K7125 using a press-molded outer layer jacket sheet. Further, as the bundle winding characteristics, when the occurrence frequency of the winding failure at the time of manufacturing the cable is 3% / lot or more, or as shown in FIG. The case where the cardboard was loaded on the truck and the roll was broken after reciprocating 300 km was marked as x.

  As a result of the evaluation, as can be seen from Table 3, it was confirmed that the friction coefficient of the outer envelope 13 was required to be 0.4 or more in order to improve the bundling characteristics. Furthermore, when the outer layer friction coefficient is 0.3 or less, it has been confirmed that the tensile resistance characteristics after attaching the jacket grip connector deteriorate in addition to bundle winding. On the other hand, if the coefficient of friction of the outer layer jacket 13 exceeds 2.0, the cables do not slide well and cannot be bundled.

  Next, when the influence of the friction coefficient of the inner layer jacket 7 of the optical fiber drop cable 1 of this embodiment was evaluated, it was as shown in Table 4. In addition, as the evaluation method, the friction coefficient of the inner-layer outer jacket 7 was measured, and the connection to the air duct was evaluated.

  At this time, the friction coefficient of the inner layer jacket 7 was measured in accordance with JIS K7125 using a press-molded inner layer jacket sheet. In addition, as the lineability to the air-conditioner duct, the inner-layer cable 11 was drawn using two air-conditioner ducts having a right bend of 3 m in length and a radius of curvature of R60 mm of 90 °. The test cable was pulled into the air conditioner duct with five φ10 mm metal cables coated with PVC remaining.

The case where the average value of the pulling load was 500 gf or less was rated as ◯, and the case where it was larger than 500 gf was marked as x. Δ is 500 gf or less, but it was assumed that a slight catch was felt during the passage.

  As a result of the evaluation, as can be seen from Table 4, it was confirmed that if the friction coefficient was 0.4 or less, the wire permeability was 500 gf or less. On the other hand, when the coefficient of friction is less than 0.1, it is necessary to add a considerable amount of a lubricant to the material of the inner layer jacket 7, and the bleed-out due to the addition will contaminate the periphery, which is not good.

  Based on the above, the good characteristics of the optical fiber drop cable 1 of this embodiment are summarized as shown in Table 5.

  The transmission loss was measured by OTDR using a 500 m long cable. As the wear resistance, a single inner layer cable 11 was used, and a PVC metal cable was attached to the steel needle portion in the item of wear resistance of the marking of the optical fiber 3 defined in JIS C6851, and the inner layer cable 11 was worn ( A reciprocating load of 3 kg and 250 cyc was performed). The case where there was no exposure of the copper wire from the metal cable or the tensile body of the inner layer cable 11 was determined as good.

  As for the kuma-zemi resistance, a 10-m test cable was laid in 50 locations in Western Japan during June to October, and the test cable was visually observed after removal, and the presence or absence of disconnection was confirmed using OTDR.

As for cold resistance, a cold resistance test of JIS C3005 was conducted on each of the outer layer jacket 13 material and the inner layer jacket 7 material, and whether or not cracking occurred at each temperature was confirmed.

  As can be seen from Table 5, the optical fiber drop cable 1 of this embodiment has transmission loss, flame retardancy, wear resistance, and detacher leadability in the cable body (the entire drop cable 1) and the inner layer cable 11 (indoor cable). As shown in Table 5, the results of good resistance against cold and peanuts and cold resistance are good.

  From the above, the optical fiber drop cable 1 of this embodiment has the following effects.

(1) The outer layer jacket 13 and the inner layer jacket 7 have a separable two-layer structure, and the outer layer jacket 13 is torn and only the inner layer cable 11 is drawn into the house as an indoor cable. In addition, since there is no need for connection with the indoor cable, the work of attaching the connector is eliminated. In addition, since the number of connection portions between the optical fibers 3 is reduced by 1, the number of places where connection loss occurs is reduced.

(2) Since the inner-layer cable 11 having the non-black inner-layer jacket 7 is mounted and only the inner-layer cable 11 can be taken out, the inner-layer cable 11 is exposed by a tool such as a detacher and surrounded by the dotted line in FIG. The cords can be compared by the ID tester of the inner cable 11 shown at the point. This makes it possible to check not only the core line contrast but also the failure point.

(3) Since the optical fiber 3 is protected by the high-strength inner layer jacket 7 having a durometer hardness (HDD) of 55 to 70, it is possible to avoid disconnection damage due to the kuma-zemi.

(4) Since the inner layer cable 11 having the low friction and wear resistance characteristics is mounted and the inner layer cable 11 can be easily taken out, the lineability into the pipe is improved due to the small diameter and low friction. Moreover, since it is abrasion-resistant, the influence of the abrasion by another cable can be reduced.

(5) Since the friction coefficient of the outer layer jacket 13 is 0.4 or more, operation in a bundled state is possible.

DESCRIPTION OF SYMBOLS 1 Optical fiber drop cable 3 Optical fiber 5 Strength member 7 Inner layer jacket 9 Inner layer notch part 11 Inner layer cable 13 Outer layer jacket 15 Outer layer notch part 17 Optical element part 17A, 17B End part 19 Neck part 21 Support line 23 Outer sheath 25 Support line part 25A, 25B End part 27 Electric pole 29 Outdoor line retainer 31 Branch closure 33 Access system optical fiber cable 35A, 35B Tool 37 Termination device (ONU)
39A, 39B Chuck 41 Bundled product 43 Stretch film

Claims (5)

One or more optical fibers disposed in the center;
The optical fiber extends in the same direction as the longitudinal direction of the optical fiber on both sides of the optical fiber on a straight line that is parallel to one of the two directions orthogonal to the longitudinal direction of the optical fiber and passes through the center of the optical fiber. A pair of tensile bodies arranged;
The friction coefficient that integrally coats the outer periphery of the optical fiber and the pair of strength members is 0.10 or more and 0.40 or less, and the durometer hardness (HDD) is 55 or more and less than 70. An inner coat made of black resin;
An inner layer jacket notch portion formed on the lower and upper surfaces of the inner layer jacket which is parallel to the other direction of the two directions and passes through the center of the optical fiber. Inner layer cable,
An outer layer jacket made of a resin having a friction coefficient of 0.40 or more and 2.00 or less, and a durometer hardness (HDD) of 36 to 53, covering the outer periphery of the inner layer jacket of the inner layer cable;
An outer layer outer notch formed on the lower and upper surfaces of the outer jacket that is parallel to the other of the two directions and passes through the center of the optical fiber;
The inner layer jacket and the outer layer jacket are not fused and separable, and the inner layer cable constitutes a two-layer structure that functions as an indoor cable; and
An optical fiber drop cable, characterized in that a long support wire portion in which a support wire is covered with a sheath is integrated in parallel with each other on the outer sheath of the optical element portion.   2. The optical fiber drop cable according to claim 1, wherein the inner layer outer notch portion and the outer layer outer notch portion are arranged in a line substantially on a line passing through the optical fiber.   3. The optical fiber drop cable according to claim 1, wherein a pulling force for pulling the inner layer cable from the outer layer jacket is 30 N / 20 mm or more and 500 N / 20 mm or less.   4. The optical fiber drop cable according to claim 1, wherein the inner layer jacket is made of a polyolefin resin, and the outer layer jacket is made of a polyolefin resin or a polyurethane resin.   5. The light according to claim 1, wherein the outer layer jacket is made of a resin having cold resistance with F (0) of −30 ° C. or lower in an embrittlement test according to JIS K7216. Fiber drop cable.

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