JP5654945B2 - Optical unit - Google Patents

Description

  The present invention relates to an optical unit in which an optical fiber ribbon is housed in a tube formed by forming a belt-like film into a cylindrical shape and the outer periphery of the tube is covered with a resin coating layer.

  The applicant of the present application has proposed an optical unit in which a plurality of optical fibers are housed in a cylindrical tube formed by forming a thin thermoplastic film into a cylindrical shape having overlapping portions in the circumferential direction. (For example, patent document 1 etc.). Further, the applicant of the present application connects only adjacent optical fibers among a plurality of parallel optical fibers by a connecting portion, and intermittently provides the connecting portions in the longitudinal direction of the tape core and in the width direction of the tape. In addition, an optical fiber ribbon having a so-called intermittent fixing structure has been proposed (for example, Patent Document 2). The applicant of the present application has been diligently trying to establish a technique for accommodating the optical fiber ribbon having the intermittently fixed structure in the cylindrical tube of the optical unit.

Japanese Patent Application No. 2009-260404 Japanese Patent No. 4143651

  However, the rigidity is high at a location where the number of connecting portions of the optical fiber ribbon is large, and the stiffness is low at a location where there are few connecting portions. Therefore, the optical unit in which the optical fiber ribbon is housed varies in rigidity in the cable longitudinal direction. In other words, when the direction of the bendability of the optical fiber ribbon is given, the direction of the ease of bending is similarly given to the optical unit on which it is mounted.

  Also, if the number of connecting parts on the same cross section in the tape core width direction is significantly different in the longitudinal direction of the tape core relative to the number of connecting parts on an arbitrary cross section different from this, this optical fiber tape core is mounted. The obtained optical unit has non-uniform rigidity in the cable longitudinal direction. If the bendability and rigidity are not uniform in the longitudinal direction of the cable, a large bending is locally applied to the optical unit and transmission loss is increased. Moreover, in this optical unit, there is a possibility that the film is buckled at a portion where the rigidity is small and it is easy to bend.

  In addition, the optical unit on which this optical fiber ribbon is mounted may be bent to a small diameter during intermediate branching or when handling the extra length of the optical unit in the closure. At this time, if the rigidity of the optical unit is strong, it becomes difficult to store the extra length, and if the bending property and rigidity are not uniform, problems such as local bending and buckling occur.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical unit in which the rigidity of the optical unit in the longitudinal direction of the cable is made uniform to reduce the loss of transmission loss and to prevent the film from buckling.

According to the first aspect of the present invention, an optical fiber is formed in a press-wound tube formed by forming a strip -like non-adhesive film into a cylindrical shape and abutting both ends of the film or overlapping both ends of the film in the circumferential direction. An optical unit in which a tape core is housed and an outer periphery of a tube is covered with a resin coating layer, and the optical fiber ribbon has three or more optical fibers arranged in parallel with each other Only two adjacent optical fibers are connected by a single connecting portion, and adjacent optical fibers of three or more cores are not connected by one connecting portion. It is characterized by being a tape core wire having an intermittent fixing structure provided intermittently and also intermittently provided in the width direction of the tape core wire.

  Invention of Claim 2 is the optical unit of Claim 1, Comprising: The said connection part provides one or more on the same cross section in any position of the tape optical fiber longitudinal direction of the said optical fiber tape optical fiber. It is characterized by being.

  A third aspect of the present invention is the optical unit according to the first aspect, wherein the same number of the connecting portions are provided on the same cross section at any position in the longitudinal direction of the optical fiber ribbon. It is characterized by being.

  The invention according to claim 4 is the optical unit according to claim 2, wherein the number of the connecting portions on the same cross section at a certain arbitrary position is different from the number on another arbitrary same cross section. It is characterized by having.

  The invention according to claim 5 is the optical unit according to claim 2, wherein when there are two or more connecting portions on the same cross section, each connection is made on all the same cross sections of the two or more cross sections. It is characterized by the equal distance between the parts.

Invention of Claim 6 is an optical unit of Claim 1, Comprising: The number of the connection parts in the same cross section of a tape core line width direction is 1 or more, 0, 1 or more, 0 The cycle is provided in the longitudinal direction of the tape core, and the length of the connecting portion in the longitudinal direction of the tape is longer than the distance between the connecting portions in the longitudinal direction of the tape core at the zero cross-section position. And when there are a plurality of connecting parts in the same cross section, the facing distances between the connecting parts are equal.

Invention of Claim 7 is the optical unit of Claim 1, Comprising: The number of the connection parts in the same cross section of a tape core line width direction is 1 or more, and 0 period is one period, and it is the same One block having 6 units of the one cycle having a length and one unit having the one cycle having a longer length as one unit is repeatedly provided in the longitudinal direction of the tape core and arranged in parallel. The length between the front and rear connecting portions in the longitudinal direction of the tape core between the nth and n + 1th optical fibers (n is a multiple of 4) of the optical fiber is changed in the longitudinal direction of the tape core between the other optical fibers. It is characterized by being longer than the length between the connecting portions.

  According to the present invention, the connecting portion of the optical fiber ribbon with the intermittently fixed structure is a structure in which only two adjacent optical fibers are connected, and the connecting portion is intermittent in the longitudinal direction of the tape core. Since it is provided intermittently in the width direction of the tape core, the rigidity is lower than that of the optical fiber ribbon in which three or more adjacent optical fibers are connected by a connecting portion, and the tape core The rigidity in the longitudinal direction becomes uniform. As a result, in the optical unit in which the optical fiber ribbon is mounted, it is easy to bend not only in the longitudinal direction of the cable but also in any direction, and the transmission loss is not reduced and the film is not buckled.

FIG. 1: shows the optical unit of 1st Embodiment, (A) is the perspective view which removed and showed some films and resin coating layers, (B) is sectional drawing of the AA line position of (A). is there. FIG. 2 is a plan view showing a simplified optical fiber ribbon constituting the optical unit of FIG. FIG. 3 is a cross-sectional view taken along the line BB in FIG. 2, and shows both an example in which two optical fibers are in contact and an example in which they are close to each other without contact. FIG. 4 is a plan view schematically showing the optical fiber ribbon that constitutes the optical unit of the second embodiment. FIG. 5 is a plan view schematically showing the optical fiber ribbon that constitutes the optical unit of the third embodiment. FIG. 6 is a plan view schematically showing the optical fiber ribbon that constitutes the optical unit of the fourth embodiment. FIG. 7 is a plan view schematically showing the optical fiber ribbon that constitutes the optical unit of the fifth embodiment. FIG. 8 is a plan view showing a simplified optical fiber ribbon constituting the optical unit of the sixth embodiment. FIG. 9 is a plan view schematically showing the optical fiber ribbon that constitutes the optical unit of the seventh embodiment. FIG. 10 is a diagram showing a sample of the optical fiber ribbon used for performing a bending test and a kink test on the optical unit to evaluate the transmission loss and the jumping of the optical fiber.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

[First Embodiment]
First, an optical unit 1 according to a first embodiment to which the present invention is applied will be described with reference to FIGS. As shown in FIG. 1, the optical unit 1 is an optical fiber tape having an intermittently fixed structure in which three or more optical fibers 2 are arranged in parallel and two adjacent optical fibers 2 are connected by a connecting portion. It comprises a core wire 3, a tube 4 formed into a cylindrical shape by a film that accommodates the optical fiber tape core wire 3 therein, and a resin coating layer 5 that covers the outer periphery of the tube 4.

As shown in FIGS. 2 and 3, the optical fiber ribbon 3 includes, for example, 12 optical fibers 2 (2 ₁ to 2 ₁₂ ) arranged in parallel on the same line and adjacent to each other. The fibers 2 are connected by a connecting portion 6, and the connecting portion 6 is intermittently provided in the tape core wire longitudinal direction Y and also intermittently provided in the tape core wire width direction X.

  In FIG. 2, in order to make it easy to understand the arrangement state of the connecting portion 6 of the optical fiber ribbon 3, a gap is provided between the adjacent optical fibers 2. In the connection part 6, as shown in FIG. 3, the adjacent two optical fibers 2 may or may not be in contact with each other. In the connecting portion 6, adjacent two optical fibers 2 come close to each other without being in contact with each other, and UV curable resin is filled in a substantially V-shaped recess formed in the upper and lower portions of the two optical fibers 2. Alternatively, it is formed by filling and covering so as to cover the gap between both optical fibers 2 and the entire outer peripheral surface of both optical fibers 2. FIGS. 3A and 3B are examples in which two optical fibers 2 are in contact, and FIGS. 3C and 3D are non-contact without two optical fibers 2 being in contact. It is an example. 3A and 3B, the portion filled with the ultraviolet curable resin is the inner peripheral surface portion of both optical fibers 2, and the other outer peripheral surface portion is not coated with the ultraviolet curable resin. In FIGS. 3C and 3D, the portion covered with the ultraviolet curable resin is the gap between both optical fibers 2 and the entire outer peripheral surface of both optical fibers 2. 3A and 3C, the upper and lower surfaces 6a and 6b of the connecting portion 6 are parallel to the horizontal plane when the optical fiber ribbon 3 is placed on the horizontal plane. 3B and 3D, the upper and lower surfaces 6a and 6b of the connecting portion 6 are each formed in an arc shape that is slightly recessed toward the contact point of both optical fibers 2.

Further, as shown in FIG. 2, one connecting portion 6 is provided on the same cross section at any position in the longitudinal direction Y of the optical fiber ribbon 3. For example, when the first optical fiber 2 ₁ , the second optical fiber 2 ₂ ... The twelfth optical fiber 2 ₁₂ are sequentially formed from the left side to the right side in FIG. 6 is a 10th optical fiber _{2 10} provided between the eleventh optical fiber _{2 11.}

10th optical fiber 2 ₁₀ and the connecting portion 6 provided between the eleventh optical fiber 2 _11, one on the same cross-section (I-I cross section in FIG. 2) in the connection portion 6 is provided a position Only provided. Similarly, connecting portion 6 which is provided with sixth optical fiber 2 ₆ provided immediately behind the ribbon lengthwise direction Y of the connecting portion 6 between the seventh optical fiber 2 _7, the connecting portion 6 Only one is provided on the same cross section (II-II cross section in FIG. 2) at the provided position. Hereinafter, only one connecting portion 6 provided in the longitudinal direction Y of the tape core wire is similarly provided on the same cross section at the position where the connecting portion 6 is provided.

  In addition, when both end edges of the connecting portion 6 in the longitudinal direction Y of the tape core in FIG. 2 are the front end edge 6A and the rear end edge 6B, the rear edge portion of the connecting portion 6 provided on the II cross section in FIG. 6B and the front end edge 6A of the connecting portion 6 provided on the II-II cross section immediately behind it are on the same line in the tape core width direction X. All of the connecting portions 6 that are arranged back and forth in the longitudinal direction Y of the tape core wire are arranged in the above-described relationship.

  Further, the length L1 of the connecting portion 6 in the longitudinal direction Y of the tape core wire is shorter than the length L2 of the non-connecting portion up to the next connecting portion 6 on the same line. For example, the length L1 of the connecting portion 6 is 15 mm, and the L2 is about 135 mm. These lengths are all examples, and are not limited to these lengths. In addition, all the magnitude | sizes of the connection part 6 shall be substantially the same (a little error is included) (it is the same in all the following embodiments).

  The optical fiber ribbon 3 having the above-described configuration is housed in a cylindrical tube 4 that is rounded or folded in the tape ribbon width direction X because the connecting portions 6 are regularly arranged in a staggered manner. Yes. A state in which the optical fiber ribbon 3 is housed in the tube 4 is shown in FIG.

  As shown in FIG. 3, the optical fiber 2 constituting the optical fiber ribbon 3 is colored with a first coating layer 8 coated with an ultraviolet curable resin around a quartz glass fiber 7 provided in the center and colored. It consists of a colored optical fiber having a second coating layer 9. In FIG. 1, the cross section of the optical fiber 2 is shown in a simplified manner. The structure of the optical fiber 2 shown in FIG. 3 is an example of the present invention, and the present invention is not limited to this structure.

  As shown in FIG. 1, the tube 4 is formed by forming a cylindrical shape so that film end edges 10 a and 10 b that are both ends in the width direction of the belt-like film 10 partially overlap in the circumferential direction. For example, the tube 4 is formed into a cylindrical shape by passing a film 10 in which the optical fiber tape core wire 3 is disposed inside a forming die having an inner diameter gradually reduced from an inlet toward an outlet. The film 10 for forming the tube 4 is made of a thermoplastic film such as PET (polyethylene terephthalate).

  In addition, the tube 4 may be formed in a cylindrical shape by abutting the film end edges 10a and 10b with each other without forming the film end edges 10a and 10b in the circumferential direction.

  The resin coating layer 5 is formed, for example, by applying an ultraviolet curable resin to the surface of the film 10 and drying it. In such a resin coating layer 5, the optical fiber 2 having a surplus length is accommodated in the tube 4, so that it does not jump out from the overlapping portion of the film 10, and is strong against the optical fiber 2 when the optical fiber is pulled out. It is required that the resin coating layer 5 be torn without applying tension.

  Moreover, when the adhesive force between the resin coating layer 5 and the film 10 is too strong, it becomes difficult to take out the optical fiber 2, while when the adhesive force is too weak, the resin coating layer 5 and the film 10 Peeling and falling off easily occur. The adhesion between the resin coating layer 5 and the film 10 is determined in consideration of the strength of the optical unit 1 and the ease of taking out the optical fiber 2. Examples of a method for adjusting the adhesion between the resin coating layer 5 and the film 10 include a method for changing the surface property of the film 10 and a method for adding a material for facilitating peeling to the resin. In order to change the surface property of the film 10, for example, silicone is applied to the film surface to reduce the adhesion between the film 10 and the resin coating layer 5. In the case where a material for facilitating peeling is added to the resin, for example, silicone is added to the PET constituting the film 10 and the ultraviolet curable resin constituting the resin coating layer 5.

  In the optical unit 1 of the present embodiment, when the optical fiber 2 wrapped with the film 10 is taken out, it is required to take out the optical fiber 2 so as not to affect the characteristics of the optical fiber 2 (this is called hot line branching). It is done. In order to realize this live line branching, the overlapping state (wrapping state) of the overlapping portions of the film 10, the elongation at break of the resin of the resin coating layer 5, the adhesion between the film 10 and the resin coating layer 5, This can be realized by adjusting the thickness.

  According to the optical unit 1 of the present embodiment, the connection part 6 of the optical fiber tape core wire 3 having an intermittently fixed structure is a structure in which only two adjacent optical fibers 2 are connected, and the connection part 6 is Since it is provided intermittently in the tape core wire longitudinal direction Y and also in the tape fiber width direction X, it is an optical fiber tape core in which three or more adjacent optical fibers are connected by a connecting portion. The rigidity becomes weaker than that of the wire, and the rigidity in the longitudinal direction Y of the tape core wire becomes uniform. As a result, in the optical unit 1 in which the optical fiber ribbon 3 is mounted, it is easy to bend not only in the longitudinal direction of the cable but also in any direction, and the buckling of the film 10 does not occur without reducing transmission loss.

  For example, in the optical fiber tape core wire 3 in which many optical fibers 2 are connected with 3 cores and 4 cores at the connecting portion 6, the direction of the bendability comes out, so the optical unit in which the optical fiber tape core wire 3 is mounted. 1 also has directionality in bendability. However, in the optical unit 1 of this embodiment, since only the two optical fibers 2 are connected by the connecting portion 6, these problems can be solved.

  Further, according to the optical unit 1 of the present embodiment, since one connecting portion 6 is provided on the same cross section at any position in the longitudinal direction Y of the tape core, the rigidity in the longitudinal direction Y of the tape core is determined. The position is uniform. On the other hand, if the number of connecting portions 6 provided on the same cross section at an arbitrary position in the longitudinal direction Y of the tape core is greatly different at each position, the rigidity of the longitudinal direction Y of the optical fiber ribbon 3 is increased. It becomes non-uniform. As a result, in the optical unit 1 on which the optical fiber ribbon 3 is mounted, a large bending is locally added, the loss of transmission loss is increased, and the film 10 is buckled at a portion where the rigidity is small and the bending is easy. However, in the optical unit 1 of the present embodiment, these problems can be solved.

[Second Embodiment]
FIG. 4 is a plan view schematically showing the optical fiber ribbon that constitutes the optical unit of the second embodiment. The second embodiment is an example in which one connecting portion 6 is provided on the same cross section at any position in the longitudinal direction Y of the tape core, like the optical fiber tape core 3 of the first embodiment. There are 6 different arrangement patterns. Here, only the arrangement pattern of the connecting portions 6 will be described.

  In FIG. 4A, the connecting portions 6 that connect the two adjacent optical fibers 2 of the 12 optical fibers 2 arranged in parallel to each other are connected to the adjacent connecting portions 6 in the tape core width direction X. The front end edge 6A and the rear end end 6B are arranged on the same line, thereby forming an array pattern inclined obliquely downward to the right in plan view.

In FIG. 4 (B), the connection part 6 which connects between the two adjacent optical fibers 2 of the 12 optical fibers 2 arranged in parallel in one row is connected to each other in the tape core wire longitudinal direction Y. plane with vertices one are arranged, respectively (connection portion 6 is one) back and forth spaced between, also the sixth optical fiber 2 ₆ connecting portions 6 between the seventh optical fiber 2 ₇ in It is a substantially V-shaped array pattern. Note that the sixth optical fiber 2 ₆ and the connecting portion 6 between the seventh optical fiber 2 _7, a seventh optical fiber 2 ₇ only the connecting portion 6 between the eighth optical fiber 2 _8, another The front edge 6A and the rear edge 6B of the connecting portion 6 are arranged on the same line.

  In FIG. 4C, the connecting portions 6 that connect the two adjacent optical fibers 2 of the twelve optical fibers 2 arranged in parallel to each other are connected to each other in the tape core longitudinal direction Y. In FIG. 1, the connecting portions are arranged one behind the other (one connecting portion 6), and the arrangement pattern is inclined obliquely downward to the right in plan view.

  4A, 4B, and 4C, the optical fiber tape core wire 3 of FIG. 4A is the same as the optical fiber tape core wire 3 of Embodiment 1 shown in FIG. Is also provided with one connecting portion 6 on the same cross section. In the optical unit 1 in which these optical fiber ribbons 3 are mounted, as in the optical unit 1 of the first embodiment, the rigidity in the cable longitudinal direction is uniform, local bending is difficult to be applied, and reduction in transmission loss is suppressed. can do.

[Third Embodiment]
FIG. 5 is a plan view schematically showing the optical fiber ribbon that constitutes the optical unit of the third embodiment. In the third embodiment, an optical fiber tape core wire 3 having an intermittent fixing structure in which two adjacent optical fibers 2 are connected by a connecting portion 6 is connected on the same cross section at any position in the longitudinal direction Y of the tape core wire. This is an example in which the same number (two) of the parts 6 are provided.

  Two connecting portions 6 are provided on the same cross section (III-III cross section in FIG. 5) where the connecting portion 6 provided on the foremost side in FIG. 5 is located. Two connecting parts 6 are also provided on the same cross section (IV-IV cross section in FIG. 5) where the connecting part 6 provided immediately behind the longitudinal direction Y of the tape core of the connecting part 6 is located. . Hereinafter, any two connecting portions 6 provided in the longitudinal direction Y of the tape core wire are similarly provided in the same number in the same cross section at the position where the connecting portion 6 is provided.

  The optical fiber tape core wire 3 of Embodiment 3 has a structure in which the same number (two) of connecting portions 6 are provided on the same cross section at any position in the tape core longitudinal direction Y. In Y, the rigidity is uniform at any position. Therefore, in the optical unit 1 in which the optical fiber ribbon 3 is mounted, the rigidity in the cable longitudinal direction is uniform, local bending is difficult to be applied, and a reduction in transmission loss can be suppressed.

[Fourth Embodiment]
FIG. 6 is a plan view schematically showing the optical fiber ribbon that constitutes the optical unit of the fourth embodiment. In the optical fiber ribbon 3 having an intermittently fixed structure in which two adjacent optical fibers 2 are connected by a connecting portion 6, the fourth embodiment has the number of connecting portions 6 on the same cross section at a certain arbitrary position, This is an example in which the number on another same arbitrary cross section is different.

  The optical fiber ribbon 3 in FIG. 6 is an arrangement pattern of the connecting portions 6 approximate to the optical fiber ribbon 3 in FIG. 5, but on the same cross section (VV cross section in FIG. 6) at a certain arbitrary position. The number of connecting portions 6 is two, and the number of connecting portions 6 on the same cross section (VI-VI cross section in FIG. 6) immediately behind in the longitudinal direction of the tape core is one. In the optical fiber ribbon 3 of FIG. 6, the arrangement configuration in which the number of the connecting portions 6 on the same cross section is two is continuously provided, and the number of the connecting portions 6 on the same cross section is one. Is one cycle, and the arrangement pattern of the connecting portions 6 of the one cycle is repeated in the longitudinal direction Y of the tape core wire.

  Further, in the optical fiber ribbon 3, when there are two connecting portions 6 on the same cross section, the facing distance L3 between the connecting portions 6 is made equal on all the same cross sections of the two cross sections. . In the optical fiber ribbon 3 of FIG. 6, the second connecting portion 6 is provided at a position separated from the first connecting portion 6 by 5 cores.

  In the optical fiber ribbon 3 of the fourth embodiment, almost all the number of the connecting portions 6 on the same cross section is two, and the number of the other connecting portions 6 on any other same cross section is one. The rigidity is uniform at almost any position in the longitudinal direction Y of the tape core wire. Therefore, in the optical unit 1 in which the optical fiber ribbon 3 is mounted, the rigidity in the cable longitudinal direction is uniform, local bending is difficult to be applied, and a reduction in transmission loss can be suppressed.

  Further, in the optical fiber ribbon 3 of the fourth embodiment, in the portion where the two connecting portions 6 are provided on the same cross section, the facing distance L3 between the connecting portions 6 is equal in all the portions. The rigidity in the longitudinal direction Y becomes substantially uniform.

[Fifth Embodiment]
FIG. 7 is a plan view schematically showing the optical fiber ribbon that constitutes the optical unit of the fifth embodiment. In the optical fiber tape core wire 3 having an intermittent fixing structure in which two adjacent optical fibers 2 are connected by a connecting portion 6, the fifth embodiment has the number of connecting portions 6 on the same cross section at a certain arbitrary position, This is an example in which the number on another same arbitrary cross section is different.

  The optical fiber ribbon 3 in FIG. 7 has three connecting portions 6 on the same cross section (VII-VII cross section in FIG. 7) at a certain arbitrary position, and the same immediately behind the longitudinal direction Y of the tape core. The number of connecting portions 6 on the cross section (VIII-VIII cross section in FIG. 7) is two. In the optical fiber ribbon 3 of FIG. 7, four arrangements in which the number of connecting parts 6 on the same cross section is three and the arrangement of two connecting parts 6 on the same cross section are provided in succession. One cycle is taken, and the arrangement pattern of the connecting portions 6 in the one cycle is repeated in the longitudinal direction Y of the tape core wire.

  Further, in the optical fiber ribbon 3, the facing distances L <b> 4 between the three or two connecting portions 6 provided on all the same cross sections in the longitudinal direction Y of the ribbon are all equal. In the optical fiber ribbon 3 of FIG. 7, the second connecting portion 6 is provided at a position separated from the first connecting portion 6 by 4 cores at any cross-sectional position.

  In the optical fiber ribbon 3 of the fifth embodiment, the number of connecting portions 6 on the same cross section at a certain arbitrary position is three, and the number of connecting portions 6 on another arbitrary same cross section is two. Therefore, the rigidity is uniform at almost any position in the longitudinal direction Y of the tape core wire. Therefore, in the optical unit 1 in which the optical fiber ribbon 3 is mounted, the rigidity in the cable longitudinal direction is uniform, local bending is difficult to be applied, and a reduction in transmission loss can be suppressed.

  Moreover, since the optical fiber tape core wire 3 of Embodiment 5 is the site | part in which the 2 or 3 connection part 6 was provided on the same cross section, since the opposing distance L4 between each connection part 6 is equal in all the parts, The rigidity in the longitudinal direction Y of the tape core is almost uniform.

[Sixth Embodiment]
FIG. 8 is a plan view showing a simplified optical fiber ribbon constituting the optical unit of the sixth embodiment. In the sixth embodiment, in the optical fiber tape core wire 3 having an intermittent fixing structure in which two adjacent optical fibers 2 are connected by the connection portion 6, the number of connection portions in the same cross section in the tape core width direction X is determined. One or more, 0, 1 or more, and 0 periods are repeatedly provided in the longitudinal direction Y of the tape core wire as one period S. Further, in this optical fiber ribbon 3, the length L 5 of the connecting portion 6 in the longitudinal direction Y of the tape core is longer than the distance L 6 between the connecting portions 6, 6, and a plurality of connecting portions 6 in the same cross section. When there is, the facing distance L8 between each connection part 6 is an example.

  In the optical fiber ribbon 3 of FIG. 8, specifically, the number of connecting portions in the same cross section in the tape ribbon width direction X is 6, 0, 5, and 0 as one period S. It is repeatedly provided in the longitudinal direction Y of the tape core wire. Further, in this optical fiber ribbon 3, the length L 5 of the connecting portion 6 in the longitudinal direction Y of the tape is determined by the distance between the connecting portions 6, 6 (the length of the tape core at the cross-sectional position where no connecting portion is 0) The distance between the connecting portions 6 and 6 in the direction is longer than L6. Further, in the optical fiber ribbon 3, when there are a plurality of connecting portions 6 in the same cross section, the facing distance L8 between the connecting portions 6 is made equal. For example, in this example, L5 is 30 mm, L6 is 10 mm, and S is 50 mm.

  In the optical fiber ribbon 3 of the fifth embodiment, the number of connecting portions 6 on almost the same cross section is 5 or 6, so that the rigidity is uniform at almost any position in the longitudinal direction Y of the ribbon. . Moreover, in this optical fiber tape core wire 3, since the facing distance L8 of each of the plurality of connecting portions 6 on the same cross section is equal, the rigidity in the longitudinal direction Y of the tape core wire is substantially uniform. Therefore, in the optical unit 1 in which the optical fiber ribbon 3 is mounted, the rigidity in the cable longitudinal direction is uniform, local bending is difficult to be applied, and a reduction in transmission loss can be suppressed.

[Seventh Embodiment]
FIG. 9 is a plan view schematically showing the optical fiber ribbon that constitutes the optical unit of the seventh embodiment. In the seventh embodiment, in the optical fiber tape core wire 3 having an intermittently fixed structure in which two adjacent optical fibers 2 are connected by a connection portion 6, the number of connection portions 6 in the same cross section in the tape core width direction X 1 or more, and 0 period as one period S, and repeatedly provided in the longitudinal direction Y of the tape core wire, and between the n-th and n + 1-th (n is a multiple of 4) optical fibers 2 of the parallel optical fibers 2 A length L10 between the connecting portions 2 in the longitudinal direction Y of the tape core is set to be longer than a length L9 between the connecting portions 2 in the longitudinal direction Y of the tape core between the other optical fibers 2.

  In this embodiment, in one cycle S, the length in the tape core longitudinal direction Y of the part where the number of connecting portions 6 in the same cross section in the tape core width direction X is zero is another part. Longer than one cycle S ′. For example, one block B having one unit of the one cycle S having the same length and one unit of the one cycle S ′ having a length longer than that is represented by a longitudinal direction Y of the tape core wire. The arrangement pattern of the connecting portions 6 is repeated.

The arrangement pattern of the optical fiber ribbon 3, the connecting portion 6 for connecting the optical fiber 2 of 2 adjacent heart, sequentially lower right toward the 1st optical fiber 2 ₁ a twelfth optical fiber 2 ₁₂ They are arranged in a straight line diagonally. The adjacent connecting portions 6 are provided at a distance in the longitudinal direction Y of the tape core by the same length L2 as the length L1 of the connecting portion 6 in the longitudinal direction Y of the tape core. Further, in the optical fiber ribbon 3, at the site of the one cycle S ', a fourth optical fiber 2 ₄ and the connecting portion 6 between the fifth optical fiber 2 _5, and the eighth optical fiber 2 ₈ the connecting portion 6 between the ninth optical fiber 2 _9, and the number of the connecting portion 6 both on the same section of ribbon width direction X and the zero.

In the optical fiber ribbon 3 of the seventh embodiment thus configured, until the first optical fiber 2 _{1 -} fourth optical fiber 2 _4, the fifth optical fiber 2 _5-eighth optical fiber and up to 2 _8, and the number of each optical fiber 2 to the ninth optical fiber 2 _{9 ~} 12th optical fiber 2 ₁₂ becomes clarity that are each present 4. That is, according to this embodiment, it is possible to improve the discrimination as an aggregate of four-fiber ribbon units.

[Example]
Here, optical units A, B, C, in which the following four types of optical fiber ribbons are manufactured, the optical fiber ribbons are housed in a tube, and the outer periphery of the tube is covered with a resin coating layer. A bending test and a kink test were performed on D.

  As shown in FIG. 10A, the optical fiber ribbon 3A of the optical unit A has an intermittent fixing structure in which two adjacent optical fibers 2 are connected by a connecting portion 6 as in FIG. The number of connecting portions 6 on the same cross section in the line width direction is one or two. The optical fiber ribbon 3B of the optical unit B has an intermittent fixing structure in which two adjacent optical fibers 2 are connected by a connecting portion 6 as shown in FIG. The number of connecting portions 6 on the cross section is repeated in the longitudinal direction Y of the tape core wire with one cycle of 6, 0, 5, 0. The optical fiber tape core 3C of the optical unit C has an intermittent fixing structure in which the adjacent three optical fibers 2 are connected by a connecting portion 6 as shown in FIG. The number of connecting portions 6 on the same cross section is always one. However, the optical fiber tape core wire 3 </ b> C in FIG. 10C connects the three adjacent optical fibers 2 by the connecting portion 6. In the optical unit D, 12 optical fibers were used as they were without being connected at the connecting portion.

Each of the four types of optical units A to D has an outer diameter (outer diameter of the resin coating layer 5) of 1.5 mm, an inner diameter (inner diameter of the tube 4) of 1.2 mm, and the number of optical fibers 2 is twelve. The mounting density is 10.6 cores / mm ₂ .

  In the bending test, the transmission loss fluctuation was measured when the optical units A to D were wound three times around a mandrel having a radius of 30 mm. The case where the loss variation was 0.01 dB or less was evaluated as ◯, and the case where the loss variation was 0.01 or more was evaluated as ×. The bending test was performed based on IEC60794-1-2 E11A.

In the kink test, when the optical units A to D were bent until the radius became 25 mm, whether or not buckling or popping of the mounted optical fiber occurred was confirmed. The case where the crack did not occur in the tube 4 after the test was evaluated as ◯, and the case where the tube 4 was cracked after the test was evaluated as ×. The kink test was performed based on IEC 60794-1-2 E10. These results are shown in Table 1.

  Since the optical units A and B have no directionality in bending ease, no large loss fluctuation was observed in the bending test. When these two optical units A and B are compared, the optical unit A on which the optical fiber ribbon 3A shown in FIG. 10 (A) is mounted has the optical fiber ribbon 3B shown in FIG. 10 (B). It can be seen that the loss variation at the time of bending is smaller than that of the mounted optical unit B, and it is more resistant to bending. This is because the optical fiber tape core 3A of the optical unit A has a smaller number of connecting portions 6 than the optical fiber tape core 3B of the optical unit B, and the difference of the connecting portions 6 in the tape core width direction is small. Therefore, the rigidity in the cable longitudinal direction becomes more uniform. The result of the kink test was good for both light units A and B.

  In the optical unit C, since the three optical fibers 2 are connected on the same cross section in the tape core width direction, the optical fiber tape cores 3A and 3B connecting the adjacent two optical fibers 2 are connected. Thus, the rigidity becomes excessively high and rotation and movement become difficult in the tube 4 mounted at high density. When this optical unit C was bent, there was no degree of freedom in the bending direction, and the rigidity in the radial direction and the longitudinal direction was non-uniform. Therefore, non-uniform bending occurred in the bending test, resulting in large transmission loss fluctuations. Further, in this optical unit C, buckling occurred in the kink test, and the film 10 opened from the mating surface at the bent portion, and the optical fiber ribbon 3C mounted inside jumped out.

  In the optical unit D, good results were obtained for both the bending test and the kink test. As described above, the optical units A and B according to the present invention can obtain the same result as that of the optical unit D in which the 12 optical fibers 2 are simply mounted in the tube 4.

  According to the result obtained from this example, the smaller the number of connecting portions 6 on the same cross section in the tape core width direction, the lower the rigidity of the optical unit and the easier the handling. Since it becomes difficult to line up the optical fibers when the core wires are fused together, it is necessary to appropriately adjust the number and arrangement of the connecting portions 6.

  Although specific embodiments to which the present invention is applied have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made. An optical unit 1 in which one optical fiber 2 is used to form an optical fiber tape core wire 3 having an intermittently fixed structure is formed as an optical unit 1, but an optical fiber tape having an intermittently fixed structure using four optical fibers 2. An optical unit 1 in which three cores 3 are mounted and a total of 12 optical fibers 2 are accommodated may be used. Alternatively, an optical unit 1 in which two optical fiber tape cores 3 having an intermittently fixed structure using six optical fibers 2 are mounted to accommodate a total of 12 optical fibers 2 may be used. In addition to the 12-fiber optical unit, an 8-fiber optical unit or a 16-fiber optical unit may be used.

  In addition, in the optical unit 1 in which the optical fiber tape core wires 3 having a plurality of intermittent fixing structures are mounted, the cable 4 is mounted on the tube 4 so that the positions of the connecting portions 6 of the optical fiber tape core wires 3 are not aligned. It is desirable to make the rigidity in the longitudinal direction uniform.

  Further, examples of the cable on which the optical unit to which the present invention is applied include a center tube cable, a loose tube cable, a slot cable, and a C slot cable.

  INDUSTRIAL APPLICABILITY The present invention can be used for an optical unit in which an optical fiber ribbon having an intermittently fixed structure is housed in a cylindrically formed film and the film surface is covered with a resin coating layer.

DESCRIPTION OF SYMBOLS 1 ... Optical unit 2 ... Optical fiber 3 ... Optical fiber tape core wire 4 ... Tube 5 ... Resin coating layer 6 ... Connection part 6A ... Front end edge of a connection part 6B ... Rear end edge of a connection part 10 ... Film 10a, 10b ... Film Edge

Claims (3)

An optical fiber ribbon is housed in a press-wound tube formed by forming a strip-like non-adhesive film into a cylindrical shape and abutting both ends of the film or overlapping both ends of the film in the circumferential direction, and the tube An optical unit formed by coating the outer periphery of a resin coating layer,
In the optical fiber ribbon, three or more optical fibers are arranged in parallel, and only two adjacent optical fibers are connected to each other by one connecting portion, and between adjacent three or more optical fibers. A plurality of the connecting portions are provided intermittently in the longitudinal direction of the tape core and intermittently provided in the width direction of the tape core. The
In the optical unit, the same number of the connecting portions are provided on the same cross section at any position in the longitudinal direction of the optical fiber ribbon. The optical unit according to claim 1,
One or more connecting portions are provided on the same cross section at any position in the longitudinal direction of the optical fiber ribbon. The optical unit. The optical unit according to claim 2,
When there are two or more connecting portions on the same cross section, the facing distances between the connecting portions are equal on all the same cross sections of the two or more cross sections.
An optical unit characterized by that.

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