JP5371670B2 - Optical fiber and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical fiber which is endurable to external tensile force or twist having enhanced adhesive ability with an optical fiber fixing member such as a sleeve. <P>SOLUTION: The optical fiber includes at least one belt-shaped undulating part 15 which is formed on the coating part 14 of the optical fiber 10 and enhances the adhesive ability with the sleeve 20 via an adhesive 24. The undulating part 15 is extended in a part in the circumferential direction of the optical fiber. The undulating part 15 is formed by using one of a laser machining, a plastic working using a plastic working tool, a cutting work using a cutting work tool and a grinding work using a grinding tool. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an optical fiber, and more particularly to an optical fiber that increases the degree of adhesion with an optical fiber fixing member via an adhesive.

  An optical module such as an optical modulator is required to be airtight in order to protect an optical element or the like placed in the optical module. In order to maintain this airtightness, the optical fiber connected to the input / output end of the optical element is subjected to terminal processing using a terminal processing member such as a metal sleeve and a glass ferrule (see Patent Document 1).

  FIG. 8 is a cross-sectional view showing a state in which the conventional optical fiber 110 is mounted on a sleeve 20 which is a kind of terminal processing member in the terminal processing described above. A first optical fiber insertion hole 21 and a second optical fiber insertion hole 22 are formed at the rear end and the front end of the sleeve 20, respectively. The optical fiber 110 is inserted into the first optical fiber insertion hole 21 with the bare optical fiber 113 composed of a core and a clad (not shown) exposed and usually subjected to a metallization process. The inserted bare optical fiber 113 passes through the second optical fiber insertion hole 22 and is exposed from the front surface of the sleeve 20, that is, from the opening of the optical fiber insertion hole 22.

  The periphery of the opening of the optical fiber insertion hole 22 is filled with a sealing member 23 such as solder, whereby the opening is hermetically sealed (hermetic seal). On the other hand, the inside of the first optical fiber insertion hole 21 and the opening are filled with an adhesive 24. The adhesive 24 fixes the covering portion 114 of the optical fiber 110 to the sleeve 20.

JP 2008-263899 A

  With recent miniaturization of optical modules, miniaturization of terminal processing members such as sleeves is also required. However, when the optical fiber is fixed to the terminal processing member, there is no change in using an adhesive. That is, downsizing of the terminal processing member means narrowing of the area where the adhesive is applied. However, as is well known, the coated portion of the optical fiber has low adhesiveness.

  Under such circumstances, the miniaturization of the terminal processing member makes it difficult to firmly bond the optical fiber to the terminal processing member. In the configuration shown in FIG. 8 also, when the miniaturization progresses, the optical fiber 110 may be easily peeled off from the adhesive 24 by an external force such as tension or twist. Such delamination easily induces misalignment, rotation, or disconnection of the optical fiber, causing a failure of the optical module.

  The present invention has been made to solve the above-mentioned problems, and enhances the degree of adhesion with an optical fiber fixing member such as a terminal processing member via an adhesive, thereby resisting external tension and twisting. An object is to provide an optical fiber to be obtained.

A first aspect of the present invention is an optical fiber, a part of which is inserted and fixed in an optical fiber fixing member , and the longitudinal direction of the optical fiber with respect to the fixed portion of the optical fiber. When the adhesive is applied by repeatedly scanning the laser in the orthogonal direction and processing it, a band shape along the circumferential direction of the optical fiber for increasing the degree of adhesion with the optical fiber fixing member via the adhesive When the undulation portion of the optical fiber fixing member is fixed to the optical fiber fixing member, the specific same one in the circumferential direction of the optical fiber is located in the insertion hole of the optical fiber fixing member and in the vicinity of the outside of the opening in the optical fiber longitudinal direction. position is formed by arranging a plurality of the, each undulation of the plurality of, with positioned inward than the surface of the covering portion, having a 10% or less of the depth of the diameter of the covering portion It is characterized in.

The plurality of undulations may be located at the tip of the optical fiber.

The covering portion is preferably made of an elastomer made of any one of polyurethane, polyester, polyolefin, polyvinyl chloride, and nylon.
The optical fiber fixing member is fixed to the optical fiber by a sealing member,
Preferably, the optical fiber fixing member is filled with an adhesive, the adhesive is applied to the opening of the optical fiber fixing member, and the entire undulating portion is covered with the adhesive .

A second aspect of the present invention is a method of manufacturing an optical fiber, the step of fixing an optical fiber having a covering portion, and a direction perpendicular to the longitudinal direction of the optical fiber with respect to the covering portion of the fixed optical fiber. By scanning and processing the laser repeatedly, the band-like undulations along the circumferential direction of the optical fiber to increase the degree of adhesion with the cylindrical optical fiber fixing member via the adhesive are fixed to the optical fiber fixing member. as the vicinity of the outside of the insertion hole and the opening portion of the optical fiber fixing member in longitudinal direction of the optical fiber when, and forming side by side a plurality of the identification of the same one position in the optical fiber circumferential direction In the step of forming the undulating portion, each of the plurality of undulating portions is located inward of the surface of the covering portion and has a depth of 10% or less of the diameter of the covering portion. Characterized in that it is formed as.
In the optical fiber manufacturing method, it is preferable that the undulating portion is located at a tip portion of the optical fiber.
The method of manufacturing the optical fiber includes a step of fixing the optical fiber fixing member to the optical fiber by a sealing member, filling an adhesive in the optical fiber fixing member, and bonding the opening to the optical fiber fixing member Applying an agent and covering all of the undulations with an adhesive may be further included.

  According to the present invention, since the adhesive is in close contact with the undulating portion, the optical fiber and the optical fiber fixing member can be firmly bonded. That is, even if the optical fiber receives external force such as tension or twist, it can be prevented that the optical fiber is detached from the optical fiber fixing member.

1 is a perspective view of an optical fiber according to an embodiment of the present invention. It is a side view of the optical fiber of FIG. It is a figure which shows the AA cross section of the optical fiber shown in FIG. It is sectional drawing which shows the state which mounted | wore the terminal process member with the optical fiber which concerns on one Embodiment of this invention. It is sectional drawing of the optical fiber which concerns on one Embodiment of this invention. 1 is a perspective view of an optical fiber according to an embodiment of the present invention. It is a figure which shows the manufacturing process of the optical fiber which concerns on one Embodiment of this invention, (a) is the manufacturing process by laser processing, (b) is the manufacturing process by plastic working using a plastic working tool, (c) is cutting It is a figure which shows the manufacturing process by the cutting process using a processing tool. It is sectional drawing which shows the state which mounted | wore the terminal processing member with the conventional optical fiber.

  Embodiments of the present invention will be described with reference to the drawings. The optical fiber according to the present embodiment is an optical fiber generally called an optical fiber core, and is obtained by coating a bare optical fiber having a core and a clad with a resin or the like. In the following description, this optical fiber core wire is referred to as an optical fiber for convenience.

  1 and 2 are a perspective view and a side view of an optical fiber 10 according to the present embodiment, respectively. FIG. 3 is a view showing an AA section of the optical fiber shown in FIG. The optical fiber according to the present invention is fixed to the optical fiber fixing member using an adhesive. FIG. 4 is an example thereof, and is a cross-sectional view showing a state in which the optical fiber 10 according to the present embodiment is attached to a sleeve 20 that is a kind of optical fiber fixing member and is a known terminal processing member.

  As described above, the optical fiber 10 includes the bare optical fiber 13 including the core 11 and the clad 12 that wraps the core 11. The core 11 and the clad 12 are made of a known material (such as quartz glass).

  The optical fiber 10 further includes a covering portion 14 that covers the bare optical fiber 13. The covering portion 14 forms a coaxial structure around the central axis O together with the core 11 and the clad 12. The covering portion 14 is formed of a known synthetic resin. As will be described later, this synthetic resin is preferably an elastic body having machinability and thermoplasticity, and suitable materials include, for example, polyurethane, polyester, polyolefin, polyvinyl chloride, and nylon elastomers. Etc.

  The covering portion 14 may have a coaxial multilayer structure made of different materials. For example, the outer periphery of the clad 12 may be surrounded by an ultraviolet curable resin (not shown), and the outer periphery may be further surrounded by the above-described elastomer. In the present invention, the undulating portion 15 described later is formed on the surface of the covering portion 14. As long as the formation of the undulations 15, the mechanical strength (such as tensile strength and torsional strength) of the cover 14, and the optical characteristics of the bare optical fiber 13 are not hindered, the structure of the cover 14 (that is, the hierarchy) There are no restrictions on the structure and materials.

  As shown in FIGS. 1 and 2, at least one strip-shaped undulation 15 is formed on the surface of the covering 14. The band-like undulations 15 extend at least partly in the circumferential direction of the optical fiber 10. The length L1 of the undulating portion 15 in the circumferential direction of the optical fiber 10 is arbitrary. As shown in FIG. 3, the undulating portion 15 may be formed shorter than the half circumference L <b> 2 of the covering portion 14, or may be formed over the entire circumference of the optical fiber 10.

  In the present embodiment, the undulating portion 15 is formed at the tip of the optical fiber 10 and improves the degree of adhesion with the optical fiber fixing member to be connected, as will be described later. Here, the “tip portion of the optical fiber” means the tip portion of the portion covered with the covering portion 14 in the optical fiber 10 after the bare optical fiber 13 is exposed. FIG. 4 shows an example in which a plurality of undulating portions 15 are provided at the above-described distal end portion. Among these, the undulating portion 15 a is located in the first optical fiber insertion hole 21 in a state where the optical fiber 10 is completely inserted into the sleeve 20. Further, the undulating portion 15 b is located near the outside of the rear end surface 20 a of the sleeve 20. Note that either the undulating portion 15a or the undulating portion 15b may be provided. As understood from the positions of these undulations 15 (15a, 15b), the length of the tip (of the optical fiber 10) defined in this embodiment is the dimension of the optical fiber fixing member to be connected. Depends on shape.

  As described above, the adhesive 24 is applied to the undulating portion 15 and the surrounding covering portion 14. In order to improve the adhesiveness with the adhesive 24, it is desirable to increase the surface area of the region where the adhesive 24 is applied. Therefore, the undulating portion 15 is subjected to a rough surface treatment that causes minute irregularities. This rough surface treatment can be performed by any one of laser processing, plastic processing using a plastic processing tool, cutting processing using a cutting processing tool, and grinding processing using a grinding processing tool, which will be described later. The undulating portion 15 may be positioned substantially on the same plane as the surface of the covering portion 14 as viewed from the central axis O, but as shown in FIG. 3, the undulating portion 15 may be positioned inward from the surface of the covering portion 14. More preferred. In this case, the filled adhesive 24 is solidified into a wedge shape. The adhesive 24 solidified in a wedge shape functions as a so-called anchor that prevents the optical fiber 10 from coming out of the sleeve 20.

  For example, the undulating portion 15 may be formed in a concave shape as a whole along the central axis O, or may be formed in a substantially U-shaped cross section with respect to the circumferential direction of the optical fiber 10. In other words, the undulating portion 15 is formed such that a curved surface obtained by averaging the roughness of the surface can obtain the above shape. In the example of FIG. 3, the bottom portion 15 a of the undulating portion 15 extends along the circumferential direction of the optical fiber 10, but the bottom portion 15 a may extend in a direction perpendicular to the central axis O. Good. The overall shape of the undulating portion 15 is not limited to the above example, but in any case, the mechanical strength of the covering portion 14 needs to be maintained. Therefore, the depth D of the curved surface with reference to the outer peripheral surface of the covering portion 14 is up to about 10% of the diameter of the covering portion 14 (see FIG. 3).

  An example in which the optical fiber 10 according to the present embodiment is attached to the sleeve 20 will be described with reference to FIG.

  The sleeve 20 is a metal cylinder. A first optical fiber insertion hole 21 is formed at the rear end of the sleeve 20. The first optical fiber insertion hole 21 extends forward (leftward in FIG. 4) and communicates with the second optical fiber insertion hole 22. The second optical fiber insertion hole 22 is formed from the bottom of the first optical fiber insertion hole 21 toward the front of the sleeve 20 and opens at the front surface of the sleeve 20. The first optical fiber insertion hole 21 has a slightly larger diameter than the covering portion 14, and the second optical fiber insertion hole 22 has a diameter through which only the bare optical fiber 13 can pass.

  The optical fiber 10 is subjected to a metallization process by exposing the bare optical fiber 13, and is inserted into the first optical fiber insertion hole 21 in that state. The inserted bare optical fiber 13 passes through the second optical fiber insertion hole 22 and is exposed from the front surface of the sleeve 20. At this time, the end surface 14a of the covering portion 14 comes into contact with the bottom of the first optical fiber insertion hole 21 (that is, the boundary surface between the first optical fiber insertion hole 21 and the second optical fiber insertion hole 22). To prevent insertion. Therefore, the covering portion 14 stays in the first optical fiber insertion hole 21, and the undulating portion 15 is located inside the first optical fiber insertion hole 21 and around the opening (near the outside of the opening).

  The inside of the second optical fiber insertion hole 22 and the opening are filled with a sealing member 23 such as solder, and the opening is hermetically sealed (hermetic seal). In the example shown in FIG. 4, the sealing member 23 is filled up to the inside (back) of the second optical fiber insertion hole 22 in order to sufficiently achieve this hermetic sealing. When the optical fiber 10 is applied as an input / output end of an optical module (not shown) such as an optical modulator, the bare optical fiber 13 subjected to metallization is terminated by being inserted into a glass capillary (not shown). Is done. The terminated bare optical fiber 13 is bonded together with a glass capillary to an optical element (not shown) in the optical module using an ultraviolet curable adhesive or the like.

  On the other hand, an adhesive 24 is applied to the optical fiber 10 inserted into the sleeve 20 so as to cover the covering portion 14 and the undulating portions 15 (15a, 15b). The adhesive 24 is not only applied to the rear end surface 20a of the sleeve 20 and the covering portion 14 exposed from the rear end surface 20a, but also filled into the first optical fiber insertion hole 21. In addition, when the adhesive 24 is applied to the rear end surface 20a of the sleeve 20, the inside of the first optical fiber insertion hole 21 is sealed together with the above-described hermetic sealing, and air tends to remain. If air remains, it will become difficult to fill the first optical fiber insertion hole 21 further. In order to avoid this, after the adhesive 24 is applied, the periphery of the sleeve 20 is exhausted using, for example, an exhaust device (not shown). By this exhaust, the air remaining in the first optical fiber insertion hole 21 expands due to the differential pressure with the outside, and as a result, is discharged to the outside through the applied adhesive 24. The applied adhesive 24 is buried in the gap generated by the discharge. The adhesive 24 can be filled in the first optical fiber insertion hole 21 by appropriately repeating the above application and exhaust. Since the adhesive 24 is applied to the opening of the first optical fiber insertion hole 21, the adhesive 24 has a substantially conical shape as shown in FIG. 4 and joins the covering portion 14 and the sleeve 20.

  By such application and filling of the adhesive 24, the adhesive 24 covers the undulating portion 15. At this time, the adhesive 24 adheres to the minute irregularities formed on the undulating portion 15 without any gap. Since the contact area between the adhesive 24 and the optical fiber 10 increases due to this close contact, the degree of adhesion between the optical fiber 10 and the sleeve 20 is improved.

  As described in the section of the prior art, the covering portion 14 generally has low adhesion to the adhesive due to its flatness and material characteristics. In order to compensate for this, in the present invention, the degree of adhesion of the adhesive 24 to the optical fiber 10 is improved by providing the undulating portion 15 to ensure a large contact area with the adhesive 24. Therefore, peeling of the adhesive 24 from the optical fiber 10 is suppressed.

  In the present invention, the depth of the undulating portion 15 is limited to about 10% of the diameter of the covering portion 14. Therefore, the original mechanical strength of the covering portion 14 is not impaired, and the optical fiber 10 and the sleeve 20 can be firmly bonded even when the optical fiber 10 receives an external force due to tension or twist. Therefore, the occurrence of cracks in the undulating portion 15 and the like is suppressed, and disconnection of the optical fiber 10 can be avoided.

  When the undulating portion 15 is formed in a groove shape, the adhesive 24 solidifies in a wedge shape in the undulating portion 15. The adhesive 24 solidified in a wedge shape can prevent the optical fiber 10 from coming out of the sleeve 20.

  Hereinafter, modifications of the undulating portion according to the present invention will be described. In the following modification, the same reference numerals are given to the same members as those described above, and detailed description thereof is omitted.

  In the optical fiber 10 according to the present invention, as shown in FIG. 5, a plurality of undulations 15 may be provided at intervals in the circumferential direction of the optical fiber. In the example of this figure, the two undulating portions 15 are provided facing each other so as to sandwich the central axis O on the same plane orthogonal to the central axis O. In this case, since the high adhesiveness of the adhesive 24 can be obtained in the upper and lower sides of FIG. 5, the twist of the optical fiber 10 around the central axis O can be more effectively prevented.

  When a plurality of undulating portions 15 are provided at different positions in the circumferential direction of the optical fiber 10, the positions of the undulating portions 15 may differ in the extending direction of the central axis O. That is, when the plurality of undulating portions 15 that are separated in the extending direction are viewed from the central axis O, the respective positions in the circumferential direction may be different from each other. Also in this case, the adhesion degree of the adhesive 24 is improved, and the same effect as described above can be obtained.

  Further, as shown in FIG. 6, the undulating portion 15 may be formed so as to extend long in the extending direction of the central axis O. However, the length (width) of the undulating portion 15 in the extending direction depends on the structure of the optical fiber fixing member (the first optical fiber insertion hole 21 in the present embodiment). Even when such undulations are formed, the degree of adhesion of the adhesive 24 is improved, and the same effect as described above can be obtained.

  A method for processing the undulating portion of the optical fiber according to the present embodiment will be described. Similar to the description of the modified example, the same members as those described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  As described above, the undulating portion 15 is formed to be rougher than the surface of the covering portion 14. For the rough surface treatment of the undulating portion 15, any one of laser processing, plastic processing using a plastic processing tool, cutting processing using a cutting processing tool, and grinding processing using a grinding processing tool can be employed.

  FIG. 7A is a process diagram when laser processing a plurality of optical fibers 10. As shown in this figure, at least one optical fiber 10 is fixed in a predetermined direction S1, and the laser LA is scanned in a direction S2 perpendicular to this direction. In order to form the undulations 15 along the circumferential direction of the optical fiber 10, the optical fiber 10 may be rotated as appropriate. The laser LA is focused on the coating portion 14 and has sufficient power to locally evaporate the coating portion. For example, a pulse laser such as a CO2 laser is used. In laser processing, the laser LA can be condensed, so that rough surface treatment with minute irregularities is easy. Further, since the covering portion 14 is temporarily dissolved in laser processing, it is difficult to form sharp irregularities that cause cracks, and the mechanical strength of the covering portion 14 can be maintained. Further, since a plurality of optical fibers 10 can be processed at a time, it is suitable for mass production.

  FIG.7 (b) is process drawing which shows an example of the plastic working by a plastic working tool. In this example, a mold K is used as a plastic working tool. The mold K is heated to a temperature equal to or higher than the melting point of the covering portion 14 when the undulating portion 15 is formed. As shown in FIG. 7B, the mold K has a minute curved surface 31 on the pressing surface (blade edge) 30 against the covering portion 14. The curvature (radius) of the curved surface 31 preferably has a value from the radius of the covering portion 14 to 80% of the radius. In other words, it is desirable that the curvature take a value obtained by subtracting 10% of the diameter of the covering portion 14 from the radius of the covering portion 14 or the radius. Further, the length along the curved surface 31 in the longitudinal direction of the mold K (that is, the direction S2 in FIG. 7B) is equal to or less than a half circumference of the covering portion 14. Furthermore, minute irregularities for increasing the contact area with the adhesive 24 may be provided on the curved surface 31.

  When forming the undulations 15, the optical fiber 10 is arranged and fixed on the support base B in a predetermined direction S <b> 1. Next, the mold K is disposed above the optical fiber 10 along a direction S2 orthogonal to the direction S1. Thereafter, the mold K is moved toward the support base B and pressed so as to sandwich the optical fiber 10. The pressing amount of the mold K is 10% or less of the diameter of the covering portion 14. That is, the pressing amount is such that the undulating portion 15 having the depth D shown in FIG. 3 is formed. Since the mold K has already been heated to the melting point of the covering portion 14 or higher, the pressed region is melted, and the undulating portion 15 shown in FIGS. 1 and 6 is formed. Thereafter, the mold K is moved in a direction opposite to the direction in which the mold K is pressed and separated from the optical fiber 10, and the formation process of the undulating portion 15 is completed. In addition, in order to form the undulating portion 15 along the circumferential direction of the optical fiber 10, the optical fiber 10 may be rotated as appropriate.

  The same effect as laser processing can be obtained by plastic processing using a mold or the like. The pressing surface 30 of the mold K may be a simple flat surface that does not have the curved surface 31. Also in this case, the undulating portion 15 can be formed by the above-described pressing.

  FIG.7 (c) is process drawing which shows an example of the cutting process by a cutting tool. In this example, a file C is used as a cutting tool. In this cutting process, as shown in FIG.7 (c), the optical fiber 10 is arrange | positioned in the predetermined direction S1. The file C cuts the coating | coated part 14 along the direction S2 orthogonal to direction S1, and forms the undulation part 15. FIG. In this case, since the undulating portion 15 is formed along the circumferential direction of the optical fiber 10, the optical fiber 10 may be appropriately rotated. The cutting depth is 10% or less of the diameter of the covering portion 14. Although the undulation degree of the cut surface depends on the roughness of the file, the contact area with the adhesive can be increased at any roughness. Cutting with a cutting tool such as a file is simple and advantageous in terms of cost because it does not place a burden on capital investment.

  The cutting tool may be a tool having a blade at the tip, such as a cutter, in addition to a file. Moreover, you may use the grinding tool which has a grinding surface like a grindstone. It is possible to form the undulating portion based on the above-described process even by grinding with such a grinding tool.

  As described above, the optical fiber according to the present invention has been described using the form fixed to the sleeve. However, the optical fiber fixing member to which the optical fiber according to the present invention is fixed is not limited to the sleeve described in the above embodiment. That is, the optical fiber fixing member is not limited to an optical member such as a sleeve, an optical ferrule, or an optical connector, and may include a circuit board, a housing, and the like. The material of the optical fiber fixing member according to the present invention is not limited to the metal described in the present embodiment, and may be glass, resin, or the like.

  Furthermore, the position of the undulating portion according to the present invention is not limited to the tip portion of the optical fiber. For example, when the optical fiber according to the present invention is inserted and fixed in a through hole provided in the housing, the undulating portion is formed so as to be located in or around the through hole. Therefore, the position of the undulations depends on the length of the optical fiber drawn out.

DESCRIPTION OF SYMBOLS 10 ... Optical fiber, 11 ... Core, 12 ... Cladding, 13 ... Bare optical fiber, 14 ... Covering part, 15 ... Unraveling part, 20 ... Terminal processing member (sleeve , 21... First optical fiber insertion hole, 22... Second optical fiber insertion hole, 23... Sealing member, 24. ... Bare optical fiber (conventional), 114 ... Covering part (conventional)

Claims (7)

In an optical fiber, a part of which is inserted and fixed in an optical fiber fixing member,
When the adhesive is applied by repeatedly scanning the laser in the direction orthogonal to the longitudinal direction of the optical fiber and processing the coated portion of the fixed optical fiber, the optical fiber is passed through the adhesive. When the band-like undulations along the circumferential direction of the optical fiber for increasing the degree of adhesion to the fixing member are fixed to the optical fiber fixing member, the insertion holes and openings of the optical fiber fixing member in the longitudinal direction of the optical fiber as will be near outside are formed side by side a plurality of the identification of the same one position in the optical fiber circumferential direction,
Each of the plurality of undulating portions is located inward of the surface of the covering portion and has a depth of 10% or less of the diameter of the covering portion.   The optical fiber according to claim 1, wherein the plurality of undulating portions are located at a tip portion of the optical fiber.   The optical fiber according to claim 1 or 2, wherein the covering portion is made of an elastomer made of any one of polyurethane, polyester, polyolefin, polyvinyl chloride, and nylon. .   The optical fiber fixing member is fixed to the optical fiber by a sealing member,
  4. The optical fiber fixing member is filled with an adhesive, the adhesive is applied to the opening of the optical fiber fixing member, and all of the undulations are covered with the adhesive. An optical fiber according to any one of the above.   An optical fiber manufacturing method comprising:
  Fixing an optical fiber having a coating portion;
  Light for increasing the degree of adhesion with an optical fiber fixing member via an adhesive by repeatedly scanning the laser in a direction perpendicular to the longitudinal direction of the optical fiber with respect to the fixed portion of the optical fiber. When the belt-shaped undulation along the fiber circumferential direction is fixed to the optical fiber fixing member, the optical fiber circumferential direction is positioned in the insertion hole of the optical fiber fixing member and in the vicinity of the outside of the opening in the optical fiber longitudinal direction. Forming a plurality of lines at the same specific position in
Have
  In the step of forming the undulating portion, each of the plurality of undulating portions is located inward of the surface of the covering portion and has a depth of 10% or less of the diameter of the covering portion. An optical fiber manufacturing method.   The optical fiber manufacturing method according to claim 5, wherein the undulating portion is located at a tip portion of the optical fiber.   Fixing the optical fiber fixing member to the optical fiber by a sealing member;
  The method of claim 5, further comprising: filling the optical fiber fixing member with an adhesive, applying an adhesive to the opening of the optical fiber fixing member, and covering the entire undulating portion with the adhesive. An optical fiber manufacturing method.

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