JP2004184759A - Optical fiber anchoring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stable anchoring apparatus that directly anchors an optical fiber inserted into a loose tube of a submarine optical cable. <P>SOLUTION: Inside a water pressure-proof cylinder 28 of a terminal connector, a cylindrical anchoring disk 31 and a terminal fixing tool 33 are fixed to a base plate 32 as shown in Fig. (a), (b) to constitute the optical fiber anchoring apparatus. The base plate 32 is fixed indirectly to the water pressure-proof cylinder 28. The submarine optical cable 50b is inserted, a plurality of optical fibers 1a taken out of the loose tube 1 are put together into a ribbon of optical fiber 9 which is sectioned as shown in Fig. (d) by using an adhesive, guided by a winding guide 16, and wound around the outer circumferential part of the anchoring disk 31 repeatedly, and then the optical fibers 1a which have terminals clamped with the terminal fixing tool 33 and inserted into the inside with a frictional force are anchored. The anchoring disk 31 increases the force of the terminal fixing tool 33 to withstand tension applied to the optical fibers 1a. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a device for retaining a fiber optic core end of an optical cable using a loose-tube type unit as a fiber unit or having a configuration equivalent thereto, and is particularly suitable for use in a submarine optical cable to which a greater tension is applied than outside. It is something.
[0002]
[Prior art]
Developed as an optical fiber unit to be installed in the center of a submarine optical cable, to allow more optical fiber cores to be inserted in order to respond to the demand for increased communication lines, instead of the tight type optical fiber unit used conventionally. Loose tube type units tend to be used.
[0003]
The difference between the tight type unit and the loose tube type unit will be described with reference to FIG.
As shown in a schematic cross section in FIG. 4A, the tight type optical fiber unit 80 is provided with a central tensile strength member 80b such as a steel wire at the center of the optical fiber unit, and several light beams around its periphery. The fiber core 1a is filled and held through a urethane acrylate resin 80c, and the outer periphery is formed as a coating layer of a somewhat hard urethane acrylate resin or the like.
Strictly speaking, optical fibers are distinguished into optical fiber strands with primary coating on the surface of the glassy core and cladding and optical fiber cores with secondary coating on the primary coating, Hereinafter, the optical fibers will be referred to together without distinction between the element wires and the core wires.
[0004]
In the loose tube type unit 1 shown in FIG. 2B, a plurality of optical fibers 1a are made of plastic such as polybutylene terephthalate (PBT) or polypropylene (PP) via a jelly-like filler (compound) 1c. Or a loose tube 1d formed of a metal such as stainless steel.
As shown in the enlarged view E of FIG. 3C, the optical fiber 1a can be supplied in the form of an optical fiber ribbon 1e in which several optical fibers are constrained in a tape shape in advance.
[0005]
Next, an example of the structure of a submarine optical cable using a loose tube type unit will be described with reference to a perspective view of FIG. 5 and a cross-sectional view cut at a right angle to the axis of the cable of FIG. In these figures, 1 is a loose tube type optical fiber unit, 2 is a pressure-resistant layer for protecting the loose tube type unit 1 from water pressure, and a metal divided piece 2a made of iron or the like having a sectoral cross section is 3 They are used in combination vertically. The loose tube 1d is confined between the loose tube 1d and the inner surface of the pressure-resistant layer 2 with a sticky or adhesive compound 7, and the loose tube 1d is constrained through the compound 7.
On the outer periphery of the pressure-resistant layer 2, there is a tensile strength layer 3 formed by twisting a plurality of steel wires 3a so as to sufficiently cope with the tensile force applied to the cable. The compound 8 is intermittently filled in the longitudinal direction into a space defined by the outer peripheral surface of the pressure-resistant layer 2, the inner peripheral surface of the metal tube layer 4, and the outer peripheral surface of the tensile strength line 3a.
[0006]
In FIG. 5, the tensile strength layer 3, which is a single layer, is mainly formed by twisting steel wires so as to sufficiently cope with the tensile force applied to the cable.
The strength member layer 3 has a one-layer structure or a multi-layer structure, and provides a strength enough to withstand a load when the cable is laid, and protects the cable against a failure.
Reference numeral 4 denotes a metal tube layer which serves as a power supply path to the repeater while maintaining the binding and airtightness of the strength member layer 3, and is usually reduced in diameter by vertically attaching and welding a metal tape made of copper or aluminum or the like to form a tube. It was formed.
Reference numerals 5 and 6 denote insulating layers (sheaths) made of polyethylene or the like for the purpose of insulation from seawater and mechanical protection.
[0007]
For the strength member layer, a cable having a configuration different from that shown in FIGS. 5 and 6 is also used. The examples shown in the perspective view of FIG. 7 and the cross-sectional view of FIG. 8 differ in the configuration of the breakdown voltage layer. That is, it is constructed such that a pressure shell is realized on the outer periphery of the loose tube type unit 1 by a competition between the tension lines in which the pressure layer is twisted into two layers composed of the inner layer tensile line 3a and the outer layer tensile line 3b.
A compound 7 having tackiness or adhesion is filled between the outer peripheral surface of the loose tube type unit 1 and the curved surface on the side where the tensile strength line 3a faces the loose tube type unit 1, and through the compound 7, A pressure-resistant shell (substantially a shell whose diameter is the inner surface of the tensile strength line 3a) restrains the loose tube 1d.
The metal tube layer 4 and the outer insulating layers 5 and 6 have the same configuration as in FIGS.
[0008]
Such submarine optical cables are usually laid between continents or between continents and islands, so long cables are laid on the seabed via repeaters that relay transmitted signals. It is necessary to connect long cables at each location, but this kind of submarine optical cable is designed to withstand the installation and recovery in the deep sea sufficiently, and the tensile strength wire constituting the pressure resistant layer 2 and the tensile strength layer 3 described above. It is necessary to fix the so-called tensile strength members such as 3a and 3b firmly and connect the cables optically, electrically and mechanically.
[0009]
As a loose tube type optical fiber retaining device, the optical fiber is fixed so as to be covered with a coating material made of UV resin or the like at the retaining position, and then the coating material is fixed in a retaining material for retaining, There is one in which the fixing material is retained at a predetermined position (for example, see Patent Document 1).
Patent Literature 1 discloses a method in which a convex portion of a coating material is fixed so that the adhesive force between the coating of the optical fiber and the coating material and the tensile stress of the optical fiber are applied as stress in the shearing direction of the coating material. The optical fiber is retained by being fitted and fixed in the groove of the optical fiber.
[0010]
However, in a submarine cable, it is assumed that the maximum tension applied to the cable is almost equal to the breaking load of the component of each cable, so it is essential to keep all the components of the submarine optical cable. In addition, there is a case where each component member is easily pulled into the inside of the cable due to tension, and the optical fiber itself needs to be firmly fixed to the fixed portion of the terminal connection device.
In the terminal connection device, the connection portion of the optical fiber is housed in a water-resistant cylinder so as to function under high pressure on the seabed. Since the hydraulic cylinder has strength not only to withstand the high pressure of seawater but also to withstand the tension of the cables on both sides, the tension of the submarine optical cable is transmitted to each other through the hydraulic cylinder in the terminal connection device.
Therefore, in order to mechanically connect the submarine optical cable to these terminal connecting devices, the terminal such as a divided piece or a tensile strength wire is secured by fixing the terminal to the hydraulic cylinder or a member fixed thereto.
[0011]
In Japanese Patent Application No. 2002-063172 filed earlier by the present applicant, a loose tube is wound around a drum-shaped retaining disc shown in FIG. And a method of simultaneously holding the optical fiber core wires and a method of holding the optical fiber core wires in the loose tube alone using the adhesive shown in FIG.
[0012]
FIG. 9A is a cross-sectional view of a part of a joint box (JB) 20, which is a type of terminal connection device, cut along a plane including an axis of a submarine optical cable.
The water-resistant cylinder 28, which is the main body of the JB 20, is also used for supplying power to the repeater, and its surface is covered with an insulator 27.
The water-resistant cylinder 28 is a high-strength metal cylinder, and the anchor disk 11 is inserted into a hole at the center of the end plate formed at both ends thereof, and is supported by the water-resistant cylinder 28 at its flange.
The submarine optical cable 50 is inserted into the hole at the center of the insulator 27 from the right side. The submarine optical cable 50 is, for example, a type having a loose tube type unit shown in FIG.
The metal tape layer 4 and the insulating layers 5 and 6 of the cable 50 are removed, and the divided pieces 2 a constituting the pressure-resistant layer 2 and the tensile strength lines 3 a constituting the tensile strength layer 3 are spread and mounted on the tapered hole at the center of the anchor disk 11. The tapered pin 13 is pressed and clamped. The taper pin 13 is pressed by a clamp nut 15 via a flange 14 for positioning.
The tension applied to the cable 50 is transmitted via the hydraulic cylinder 28 to another optical cable connected to the left end (not shown).
[0013]
Reference numeral 60 in FIG. 9A indicates an optical fiber retaining device that retains the loose tube and the optical fiber simultaneously. The loose tube type unit 1 of the cable 50 passes through the tapered pin 13, the flange 14, and the through hole of the clamp nut 15, is guided by the winding guide 16, and reaches the inside of the water resistant cylinder 28. In the water resistant cylinder, a substantially cylindrical retaining disk 61 is fixed to a base plate 62 fixed to the anchor disk 11, and the loose tube type unit 1 is wound a plurality of times around the cylindrical surface on the outer periphery of the retaining disk. After that, the end is fixed to the base plate 62 by the terminal fixing tool 63.
The force acting on the loose tube type unit 1 from the terminal fixture 63 is enlarged by the frictional force with the wound portion of the loose tube type unit 1 wound around the retaining disc, and the loose tube type unit 1 is retained. The internal optical fiber 1a is also retained via the filled jelly-like filler 1c.
[0014]
On the other hand, the optical fiber retaining device 70 shown in FIG. 9B is a retaining device using an adhesive, and is arranged substantially at the same position as the optical fiber retaining device 60 in FIG. 9A. . The method of retaining the divided pieces 2a of the cable 50 and the tensile strength wires 3a and the like are processed in the same manner as in FIG. 9A, and the loose tube type unit 1 is linearly guided into the water resistant cylinder 28.
The loose tube 1d of the loose tube type unit 1 is fixed to the loose tube bonding tool 72 by bonding or the like.
Next, the loose tube 1d is removed from the loose tube type unit 1, the optical fiber 1a is taken out, the jelly-like filler 1c is wiped off, aligned with the groove of the optical fiber bonding tool 73, and bonded to the groove with the adhesive. An epoxy resin or a UV (ultraviolet) curable resin is used as the adhesive.
[0015]
By the way, in order to reduce the number of constituent members of the submarine optical cable, proposals have been made to substitute the function of the loose tube on the inner peripheral surface of the pressure shell.
For example, FIG. 10 is a perspective view showing the configuration of a submarine optical cable that does not have a loose tube but has an optical fiber housing structure similar to a loose tube type unit in performance.
As shown in FIG. 10, the cylindrical pressure-resistant layer 2 is formed by combining the divided pieces 2a having a fan-shaped cross section, and the compound 7 is applied densely to the gaps between the divided pieces 2a, and light is applied to the internal space. The fiber is inserted, and the gap is densely filled with a jelly-like filler 1c. The loose tube constituting the loose tube type unit is replaced by the pressure-resistant layer 2 and the compound 7, and the loose tube itself does not exist.
[0016]
The example shown in FIG. 10 lacks a loose tube, but has a space corresponding to the inner peripheral surface of the loose tube, into which an optical fiber 1a is inserted, and a jelly-like filler 1c is filled therein. The holding method has the same function as the loose tube type unit.
[0017]
[Patent Document 1]
JP 2001-108840 A
[0018]
[Problems to be solved by the invention]
A terminal connecting device used for connection of a submarine optical cable or the like needs to be miniaturized in consideration of mechanical characteristics, handling, and the like. Therefore, a device for retaining a tensile strength member of a cable is also required to be small. In the case of optical cables, it is necessary to handle the connected optical fibers so that no mechanical excessive tension is applied to them.Besides, an extra-length container that accommodates the extra length of the optical fibers is placed in the water-resistant cylinder. The fastening device is also required to be small.
[0019]
In the case of the retaining disk used in the conventional example, the device is approximately within the diameter of the retaining disk, and the diameter of the retaining disk is set in a conventional water-resistant cylinder so as not to impair the transmission characteristics of the optical fiber. Can be accommodated. On the other hand, in the case where the optical fiber cores are bonded in a straight line with an adhesive, the bonding portion is long in order to securely hold the core, and is generally much longer than the diameter of the holding disk. Since these retaining devices are housed in a hydraulic cylinder due to their configuration, there is a problem that an increase in the bonding length is directly linked to an increase in the size of the hydraulic cylinder.
[0020]
Furthermore, in the method of indirectly holding the optical fiber through the loose tube, since the frictional force works through the jelly, which exhibits fluidity at room temperature, the temperature and sea area around the cable when storing, laying, and pulling up the cable are required. There is a problem that a change in the water temperature causes a change in the friction coefficient between the loose tube and the jelly-like filler, and the friction coefficient between the jelly-like filler and the optical fiber, and a large change in the retaining force.
Further, when the optical fiber is covered with the covering material and fixed, and the covering material is fixed in the fixing material and retained, the retaining of the covering between the covering material and the optical fiber obtains the retaining force only by the adhesive force of the resin. However, in order to obtain the required retaining force, the length of the coating that is in close contact is long, which has the problem of directly leading to an increase in the size of the retaining device.
[0021]
An object of the present invention is to provide an optical fiber anchoring device for the purpose of downsizing the optical fiber core anchoring device and shortening the operation time.
[0022]
In the case of bonding, it takes 8 hours or more for a normal adhesive to expect perfect bonding, but the present invention uses a UV-curable resin, so that the time is greatly reduced. Although the UV curing resin itself is expensive and requires a special UV curing device, the working time can be reduced and the reliability for bonding can be improved.
[0023]
[Means for Solving the Problems]
The present invention provides an optical cable having a loose tube type unit in which a single core or a plurality of optical fibers are inserted through a metal or resin cylindrical tube together with a jelly-like filler in order to solve the above problems. An optical fiber anchoring device installed inside the terminal connection device to be connected and anchoring the optical fiber inserted into the optical cable, wherein the base plate is fixed to the inside of the terminal connection device, and is fixed to the base plate. A tape-shaped optical disk comprising a cylindrical retaining disk and a recording disk or a terminal fixing device attached to a predetermined position of a base plate, wherein the optical fibers are aligned and coated in a tape shape with a UV curing resin. An optical fiber in which the fiber is wound a predetermined number of times around the outer peripheral surface of the cylindrical portion of the retaining disk, and the end of the tape-shaped optical fiber is clamped and retained by the terminal fixing device. To provide the retaining instrumentation.
[0024]
Further, the base plate used in the optical fiber retaining device of the present invention is also used as a fixed portion of the terminal connection device.
Further, the outer diameter of the cylindrical portion of the retaining disk used in the optical fiber retaining device of the present invention is in the range of 30 to 100 mm, and the number of times of winding the tape-shaped optical fiber wound around the cylindrical portion of the retaining disk is reduced. 0.5 to 5 times.
Furthermore, the thickness of the tape-shaped optical fiber ranges from 0.3 to 5 mm.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
An example of an optical fiber retaining device according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1A is a projection view showing an external appearance of a joint box (JB) 20 among terminal connectors used for connection of a submarine optical cable, and FIG. 1B is a circle A shown by a chain line. 1 shows a partially cutaway perspective view of the internal structure around the retaining disc installed in the circumstance.
2A and 2B are a front view and a side view of the vicinity of the retaining disk, and FIG. 2C shows the details of the terminal fixture 33 projected from the left side of FIG. 2B. (D) is a schematic diagram showing a cross-sectional structure of the tape-shaped optical fiber 9.
[0026]
A joint box (JB) 20 shown in FIG. 1A includes components of the submarine optical cables 50a and 50b inserted into the center hole of the boot 25 from the left and right inside the joint box body 20a covered by the cover 21. Retain and connect to each other.
FIG. 1B illustrates a range indicated by a circle A substantially corresponding to the right half of the JB main body 20a by removing the water-resistant cylinder 28, the cover 21, the insulator, and a part of the mold 23. Since the left and right cable retaining structures are almost the same, a retaining device for the right cable 50b will be described. The submarine optical cable 50b is, for example, a type having a loose tube type unit shown in FIG.
[0027]
The water-resistant cylinder 28 is a high-strength metal cylindrical member, and the anchor disk 11 is inserted through holes at the center of the end plates formed at both ends thereof, and is supported.
The metal tape layer 4, the insulating layers 5, 6 of the submarine optical cable 50 inserted from the right side are removed, and the divided pieces 2a constituting the pressure-resistant layer 2 and the tensile strength lines 3a constituting the tensile strength layer 3 are located at the center of the anchor disk 11. The tapered pin 13 is spread and placed on the tapered hole, and the tapered pin 13 is pressed and clamped. The taper pin 13 is pressed by a clamp nut 15 via a flange 14 for positioning. For example, a female screw formed on the inner surface of the clamp nut 15 and a male screw formed on the outer periphery of the left end of the anchor disk 11 are screwed together to position the taper pin 13.
In this manner, the divided piece 2a and the tensile strength line 3a are retained by the anchor disk 11 and the tapered pin 13, and the tension applied to the cable 50 is applied to the cable 50a connected to the left end (not shown) via the hydraulic cylinder 28. Is transmitted.
[0028]
The loose tube 1d of the loose tube type unit 1 of the cable 50b is removed around the tapered pin 13, the flange 14, and the through hole of the clamp nut 15. The internal optical fiber 1a is pulled out, guided by the winding guide 16 so as to have a predetermined radius of curvature or more, and reaches the inside of the hydraulic cylinder 28.
The jelly-like compound 1c is wiped off from the optical fiber 1a, and is almost aligned and coated with an adhesive resin to form a flat, band-shaped tape-like optical fiber 9 having a cross section shown in FIG. 2D.
Usually, a jig having a trough-shaped depression corresponding to the tape-shaped optical fiber 9 is used, and the trough-shaped depression of the jig is filled with a required half amount of adhesive, and the optical fiber core is filled. The line 1a is almost aligned on the adhesive, covered with a half amount of the adhesive, covered with the adhesive, left to wait for the adhesive to solidify, and removed from the jig after the solidification to form the tape-shaped optical fiber 9. Is performed.
[0029]
When a UV-curable resin is used as the adhesive, the resin is irradiated with ultraviolet rays on a jig to be quickly solidified, and the coating molding is completed in a short time. The working time can be shortened, and the reliability of the bonded part can be expected to be improved. The work is performed by filling half of the resin using the above jig, aligning the optical fibers on the resin, and performing the same procedure until the half of the resin is filled. Next, if ultraviolet rays are irradiated, the solidification is completed in a short time, so that the tape-shaped optical fiber 9 is completed by removing it from the jig.
As the ultraviolet curing device, a device configured to irradiate ultraviolet light having a main wavelength of 365 nm, which includes a UV lamp such as a metal halide lamp, an irradiation device, a cooling device, and a power supply, can be used.
[0030]
By the way, as mentioned above, in order to secure the strength of the optical fiber used in the submarine optical cable, the vitreous portion constituting the core and the clad is usually covered with the primary coating immediately after drawing, and further, the secondary coating is applied. Is multiplied.
The primary coating is generally made of a thermosetting silicone resin or an ultraviolet-curing acrylic or epoxy resin. Recently, however, a UV-curing resin that can speed up drawing is often used. In many cases, the secondary coating is a colored nylon coating or a tape core wire formed by arranging a plurality of primary-coated optical fiber strands into a tape shape with a UV curable resin.
[0031]
The tape-shaped optical fiber 9 used in the present invention is also formed by coating with a UV-curable resin in the same manner as the above-described tape core wire in terms of shortening the working time, adhesion between the optical fiber and the resin, and long-term reliability. It is desirable to do. In particular, when a UV-curable resin is used for the primary and secondary coatings of the optical fiber, if the UV-curing resin is used for forming the coating of the tape-shaped optical fiber 9, the same type of resin is used. The reliability of strength can be expected.
The tape-shaped optical fiber 9 usually has a thickness of 0.3 to 5 mm and a width according to the number of the optical fibers 1a. Further, the length of the tape-shaped optical fiber 9 is set to a length corresponding to the required number of turns around the retaining disk 31 described later.
[0032]
An optical fiber retaining device according to an embodiment of the present invention is installed inside a water resistant cylinder 28, and a substantially cylindrical retaining disk 31 is fixed to a base plate 32 fixed to the water resistant cylinder 28, After the tape-shaped optical fiber 9 is wound a plurality of times around the cylindrical surface 31b on the outer periphery of the retaining disk, as shown in FIGS. 1 and 2 as an example, its end is pressed against the retaining disk by the terminal fixing member 33. Be detained.
[0033]
The base plate 32 is fixed to a component fixed to the hydraulic cylinder 28 of the joint box by, for example, a screw (not shown), and is thus fixed to the hydraulic cylinder 28. For example, it may be fixed to the anchor disk 11 supported on the water-resistant cylinder 28.
In addition, the base plate 32 does not need to be an independent member due to its nature as illustrated, and the anchor disk 11 of the terminal connection device or a component fixed thereto may also be used as the base plate.
[0034]
The retaining disc 31 has a flat cylindrical shape, and the outer diameter of the cylinder does not affect the transmission characteristics of the optical fiber 1a in the tape-shaped optical fiber 9 to be wound, and is set within a range that can be accommodated in the terminal connection device. You. Practically, the range is from φ30 to φ100 mm. Various materials such as metal and plastic can be adopted as the material forming the retaining disk 31.
As described above, the retaining disk 31 is fixed to the base plate 32 with its end face in contact. The fixing method may be any method, and for example, may be fixed by a plurality of screws as illustrated.
[0035]
The tape-shaped optical fiber 9 is wound around a cylindrical surface 31b on the outer periphery of the retaining disk 31. The number of windings is usually in the range of 0.5 (half a round) to 5 times, and is increased or decreased depending on the tension on the cable or the number of retaining cores of the fiber.
After being wound around the retaining disk 31, the terminal portion of the tape-shaped optical fiber 9 is pressed by the terminal fixing member 33 and fixed by the frictional force.
The illustrated terminal fixing member 33 is formed by bending a thin metal plate into an L shape, and one end thereof is fixed to a retaining disk 31 with a screw 33a, and the elasticity of the terminal fixing member 33 retains the tape-shaped optical fiber 9 near the distal end portion 33b. The disk-shaped optical fiber 9 is pressed against the disk 31 and is fixed by a frictional force between the tape-shaped optical fiber 9, the cylindrical surface 31 b, and the vicinity of the distal end 33 b of the terminal fixture 33.
Although the tape-shaped optical fiber 9 is vertically overlapped at two positions at the position of the terminal fixing member 33, the terminal portion of the tape-shaped optical fiber 9 on the upper side is pressed by the terminal fixing member 33 in FIG. Just fine.
[0036]
The tape-shaped optical fiber 9 is fixed by the frictional force caused by the pressing of the terminal fixing member 33. However, since the tape-shaped optical fiber 9 is wound on the cylindrical surface 31b of the retaining disc 31, the retaining disc 31 is fixed. The frictional force exerted by the cylindrical surface 31b on the tape-shaped optical fiber 9 acts as a kind of booster. Since the operation principle is described in detail in the above-mentioned Japanese Patent Application No. 2002-063172, only the conclusion will be described below.
The acting force is as shown in FIG.
[0037]
Now, the force for fixing the tip of the tape-shaped optical fiber 9 is defined as a fixing force P (kg). The fixing force P is generated by the pressing of the distal end portion 33 b of the terminal fixture 33, and acts in the axial direction of the tape-shaped optical fiber 9.
The tape-shaped optical fiber 9 is wound around the cylindrical surface 31b of the retaining disk 31 n times. The winding angle converted to radians is 2πn. Further, the friction coefficient between the tape-shaped optical fiber 9 and the cylindrical surface 31b of the retaining disk 31 is defined as μ.
On the other hand, if an external force Q (kg) for pulling the optical fiber from the cable side acts, at the point where the tape-shaped optical fiber 9 separates from the cylindrical surface 31b of the retaining disk 31, this external force Q (kg), the fixing force P and the pulling force are applied. The total frictional force that the tape-shaped optical fiber 9 receives from the retaining disc is balanced. If the direction of the force is reversed, it becomes the retaining force itself that retains the optical fiber 1a against the external force Q (in proportion to the magnitude).
[0038]
This relationship is expressed by the following equation (1).
[Q = P · exp (2πμn) ··· Equation 1]
The right side of Equation 1 is the product of the fixing force P and [the natural logarithm base e raised to the power of (2πμn)], and the frictional force exerted on the tape-shaped optical fiber 9 from the retaining disk 31 is a kind of the fixing force P. It will work as a booster.
[0039]
From this, it is shown that if the number of windings n or the friction coefficient μ is increased, the retaining force Q literally increases exponentially, and by adjusting the number of windings n of the optical fiber 1a around the retaining disk 31, A wide range of retaining force Q can be obtained with relatively small fixing force P.
The frictional force μ can be increased by taking measures such as roughening the surface of the cylindrical surface 31b of the retaining disk 31 or attaching abrasive paper to increase the retaining force Q.
[0040]
Various forms other than those described above can be employed for the shape of the terminal fixture.
Another embodiment of the terminal fixture will be described with reference to FIG. FIGS. 3A and 3B are projection views of the terminal fixture 33c as a second example, and FIG. 3A is a cross-sectional view taken along line AA in FIG.
The terminal fixture 33c is formed of a substantially rectangular elastic metal thin plate or plastic, and is slightly smaller than the thickness of the tape-shaped optical fiber 9 so that the tape-shaped optical fiber 9 can be pressed. The shape is bent in a Z-shape at substantially the center. A screw 33a inserted through a hole at one end of the terminal fixture 33c is screwed into a female screw hole formed in the cylindrical surface 31b of the retaining disk 31, thereby pressing the tape-shaped optical fiber 9 and generating a retaining force P. Let it.
As described above, it is sufficient to press and hold the tip of the tape-shaped optical fiber 9 located at the upper side in FIG. 3B, but the tape-shaped optical fiber 9 on the lower cable side is also pressed at the same time. You may.
[0041]
FIG. 3C is a partial projection view of the retaining disc 31 as viewed from above, showing a configuration of another terminal fixture, and FIG. 3D is a sectional view taken along the line DD.
A long screw 33d inserted through a pipe 33e made of rubber or plastic having elasticity is screwed into a female screw hole provided at a predetermined position on the base plate 32, and the outer peripheral surface of the retaining disk 31 and the outer periphery of the pipe 33e are formed. As a result, the tape-shaped optical fiber 9 is pressed in its thickness direction to generate a retaining force P. Since the outer diameter of the pipe 33e changes depending on the degree of screwing of the long screw 33d, fine adjustment of the retaining force P is possible.
[0042]
Various mechanical configurations of the terminal fixture may be considered in addition to the above examples, and the type of the terminal fixture is not limited to those shown in FIGS. 1 to 3.
As described above, the retaining force P may be relatively weak due to the presence of the booster wound around the retaining disc 31. Therefore, for example, it is also possible to generate a retaining force by attaching an end of the tape-shaped optical fiber 9 to the retaining disc 31 with an adhesive or sticky tape, thereby making it possible to use it as a terminal fixing device.
In short, for example, if the end of the tape-shaped optical fiber 9 is restrained by the retaining disk 31 or the base plate 32, it can be said that it functions as a terminal fixing device.
[0043]
【The invention's effect】
As described above, the optical fiber retaining device of the present invention takes out an optical fiber from a loose tube, aligns and forms a tape-shaped optical fiber, and directly winds it on a retaining disk, so that the loose tube is removed. Since the optical fibers are aligned and covered in a tape shape with the UV resin in contrast to the method of indirectly constraining the optical fibers through the media, deterioration of the transmission characteristics due to the side pressure of the optical fibers due to tension and microbends can be suppressed.
In addition, since there is a booster using a retaining disk, the fixing force (restraining force) of the tape-shaped optical fiber by the terminal fixing device may be weak, and there is an advantage that a convenient method such as the use of an adhesive tape can be adopted.
In addition, the outer diameter of the retaining disk, the number of windings, the cross-sectional size of the tape-shaped optical fiber, etc. must be large enough to be accommodated in the terminal connector used, and the outer diameter of the conventional terminal connector must be increased. It has the advantage that it can be applied without.
[0044]
If an optical cable uses a UV-curable resin for forming the optical fiber core, forming a tape-type optical fiber with the same type of UV-curable resin will provide high reliability for bonding between the optical fiber and the tape-type optical fiber. Is also an advantage of this method.
Furthermore, the use of the UV-curable resin shortens the curing time of the resin, and the cost reduction effect by shortening the working time is great.
[Brief description of the drawings]
FIG. 1 is a projection view showing an external appearance of an example of a terminal connection device, and a perspective view showing an optical fiber retaining device of the present invention installed in the terminal connection device.
FIG. 2 is a front view and a plan view of the optical fiber retaining device shown in FIG. 1, and an enlarged view of the periphery of the terminal fixture and the optical fiber tape.
FIG. 3 is a schematic diagram illustrating various types of terminal fixing devices of another type.
FIG. 4 is a schematic diagram illustrating a type of an optical fiber unit inserted into the center of a submarine optical cable.
FIG. 5 is a perspective view showing an internal structure of the submarine optical cable.
6 is a cross-sectional view of the submarine optical cable shown in FIG. 5, which is perpendicular to the longitudinal direction.
FIG. 7 is a perspective view showing an internal structure of a submarine optical cable having a different configuration from FIG.
8 is a cross-sectional view of the submarine optical cable shown in FIG. 7 perpendicular to the longitudinal direction.
FIG. 9 is a conventional example of a method for retaining an optical cable in a loose tube.
FIG. 10 is a perspective view of a submarine optical cable that does not have a loose tube but also functions as a loose tube with a pressure-resistant shell.
[Explanation of symbols]
1 Loose tube type unit, 1a optical fiber core, 80c resin, 80d coating layer, 1c jelly resin (compound), 1d loose tube, 1e optical fiber tape core, 2 pressure resistant layer, 2a divided piece, 3 tensile strength layer 3a, 3b steel wire (tensile wire), 4 metal tube layer, 5, 6 insulating layer (sheath), 7 compound (adhesive or adhesive), 8 compound (intermittent filling), 50, 50a, 50b submarine optical cable, 9 tape-shaped optical fiber, 11 anchor disk, 13 taper pin, 14 flange, 15 clamp nut, 16 winding guide, 20 terminal connection device, 20a JB main body, 21 cover, 22 insulator, 23 mold, 24 extra length container, 25 boots, 27 insulators, 28 hydraulic cylinders, 31 retaining discs, 31a screws, 3 b anchoring disc outer peripheral surface, 32 base plate, 33 terminal fixture, 33a bis, 33b tip, 33c terminal fixture C, 33d length bis, 33e pipe,

Claims (5)

A single-core or a plurality of optical fibers are installed inside a terminal connection device for connecting an optical cable having a loose tube type unit in which a jelly-like filler is inserted through a metal or resin cylindrical tube together with a jelly-like filler, and the optical fiber is inserted through the optical cable. An optical fiber retaining device for retaining the optical fiber,
A base plate fixed inside the terminal connection device,
A cylindrical retaining disk fixed to the base plate,
The retaining disc, or a terminal fixture attached to a predetermined position of the base plate,
A tape-shaped optical fiber in which the optical fibers are aligned and coated in a tape shape with a UV curable resin is wound a predetermined number of times around the outer peripheral surface of the cylindrical portion of the retaining disc, and the end of the tape-shaped optical fiber is terminated by the terminal fixing tool. An optical fiber anchoring device, wherein the optical fiber anchoring device clamps and holds a portion. The optical fiber anchoring device according to claim 1, wherein the base plate is also used as a fixed portion of the terminal connection device. 2. The optical fiber retaining device according to claim 1, wherein an outer diameter of a cylindrical portion of the retaining disk is in a range of 30 to 100 mm. The optical fiber holding device according to claim 1, wherein the number of times of winding the tape-shaped optical fiber wound around the cylindrical portion of the holding disk is 0.5 to 5 times. The optical fiber anchoring device according to claim 1, wherein the thickness of the tape-shaped optical fiber is in a range of 0.3 to 5 mm.

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