JP2011215506A - Method of manufacturing wavelength dispersion compensator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a wavelength dispersion compensator which prevents winding disorder even when a dispersion compensating optical fiber (DCF) is rewound with low tension to be formed in a coil, reduces an increase in transmission loss, is easy to manufacture, and has shock resistance.SOLUTION: The wavelength dispersion compensator is manufactured by rewinding the dispersion compensating optical fiber having been wound around a supply bobbin, onto a coil bobbin. In the method of manufacturing the wavelength dispersion compensator, after the dispersion compensating optical fiber 1 is rewound with rewiring tension controlled to be less than 10 g wt. when wound around the coil bobbin 8, a resin 12 is applied over the entire circumference of an upper surface of the coil wound around the coil bobbin to bond and fix a collar portion of the coil bobbin and the entire circumference of the upper surface of the coil. The resin is applied while the resin supply means (11a, 11b) and coil bobbin 8 are relatively rotated and moved. The resin supply means and coil bobbin have a relative rotating speed difference of ≤10 rpm.

Description

  The present invention relates to a method for manufacturing a chromatic dispersion compensator for manufacturing a dispersion compensating optical fiber by winding it around a coil bobbin.

  In an optical transmission system, a single mode optical fiber having a zero dispersion wavelength near 1300 nm is used, but this optical fiber has the smallest transmission loss near 1550 nm. For this reason, in order to perform long-distance optical transmission using this wavelength band, a chromatic dispersion compensator has been developed that cancels the chromatic dispersion near 1550 nm to zero. This chromatic dispersion compensator has a dispersion compensation optical fiber (DCF: Dispersion Compensating Fiber, hereinafter referred to as DCF) having negative dispersion at 1550 nm, and a predetermined length is coiled in accordance with the length of the optical transmission distance. Used by winding and connecting in a transmission line.

  Various chromatic dispersion compensators have been proposed. For example, Patent Document 1 discloses that DCF is wound at a winding pitch larger than the fiber diameter to suppress an increase in polarization mode dispersion (PMD), and the winding is performed during or after winding of the optical fiber. It is disclosed that transmission loss is reduced by performing distortion removal processing. Further, it is said that an increase in transmission loss can be reduced by winding the DCF with a tension of 25 g to 50 g.

  Patent Document 2 discloses that after a DCF is wound around a coil body (coil bobbin) to form a coil, it is housed in a case in a state in which the winding distortion of the coil is substantially released. In order to relieve the winding distortion of the coil, after winding the DCF around the coil body, the diameter of the body part is reduced, or the coil body is removed to form a bundle, and several coils are used to prevent the coil from collapsing. The part is fixed with resin.

Patent Document 3 discloses that DCF is wound at a winding pitch of 1.2 times or more of the fiber diameter, thereby reducing the contact between adjacent fibers and preventing an increase in loss due to temperature fluctuations. Is disclosed to be 20 to 70 g weight.
In Patent Document 4, a DCF is coiled, a coating layer in which an adhesive is applied to a part or the entire surface of the DCF is formed, a columnar part is fitted inside the coil, and a sheet is arranged on the side surface and stored in a housing. However, it is disclosed that weight reduction and cost reduction are achieved while ensuring impact resistance.

JP-A-10-31120 JP-A-10-123342 Japanese Patent Laid-Open No. 2003-149483 JP 2009-86512 A

As disclosed in Patent Documents 1 and 3, when winding the DCF around the coil bobbin, the transmission loss can be reduced by winding the DCF with a low tension. However, if the tension is too low, the winding collapses. Transmission loss may increase.
Even if the coil is not wound at a low tension, as disclosed in Patent Document 2, after winding the DCF around the coil bobbin, the bobbin body diameter is reduced, or the coil bobbin is removed to release the winding distortion, thereby preventing the coil from collapsing. It is possible to reduce transmission loss by partially applying a resin to prevent. However, in this case, there is a problem that the load is concentrated at a fixed portion by the resin, so that the impact resistance is weak, and there is also a problem of cost increase due to an increase in the number of steps.
In addition, in order to improve the impact characteristics, an adhesive is applied to a part or the entire surface of the coiled fiber wound as disclosed in Patent Document 4, and only the fiber part is accommodated in a housing in which a sheet is disposed. Is possible. However, there is a problem that the manufacturing process increases and the cost increases.

  The present invention has been made in view of the above-described situation, and even if a DCF is wound with a low tension and coiled, it does not collapse, is easy to manufacture, and is a chromatic dispersion compensator having impact resistance. The purpose is to provide a manufacturing method.

  A method of manufacturing a chromatic dispersion compensator according to the present invention is a method of manufacturing a chromatic dispersion compensator by winding a dispersion compensating optical fiber wound around a supply bobbin into a coil bobbin, and when the dispersion compensating optical fiber is wound around a coil bobbin. After the winding tension is controlled to be less than 10 g, the resin is applied to the entire circumference of the fiber upper surface wound around the coil bobbin, and the flange of the coil bobbin and the entire circumference of the fiber upper surface are bonded. It is fixed.

  The resin is applied while relatively rotating the resin supply means and the coil bobbin, and the relative rotation speed difference between the resin supply means and the coil bobbin is preferably 10 rpm or less. The winding pitch P of the dispersion compensating optical fiber is set to “d <P ≦ 2d”, where d is the outer diameter of the dispersion compensating optical fiber, and the winding distortion of the dispersion compensating optical fiber wound around the coil bobbin. It is preferable to apply resin before carrying out the treatment.

  According to the present invention, even when the DCF is wound at a low tension, resin is applied to the entire circumference of the coil upper surface wound around the coil bobbin to bond and fix the flange portion of the coil bobbin and the entire circumference of the coil upper surface. Therefore, it is not collapsed and can be given impact resistance by an easy manufacturing method.

It is a figure explaining the winding method of the dispersion compensation optical fiber by this invention, and the method of resin provision. It is a figure which shows the outline of the wavelength dispersion compensation coil by the manufacturing method of this invention. It is a flowchart which shows the outline of the manufacturing method of the wavelength dispersion compensator of this invention. It is a figure which shows the outline of a wavelength dispersion compensator. It is a figure which shows the relationship between a wavelength and transmission loss in the setting winding tension | tensile_strength of the dispersion compensation optical fiber in normal temperature (25 degreeC). It is a figure which shows the relationship between the wavelength and loss variation in the setting winding tension | tensile_strength of the dispersion compensation optical fiber in normal temperature (25 degreeC) and low temperature (-10 degreeC). It is a figure explaining the impact resistance and workability | operativity by the application amount of resin. It is a figure explaining the relationship between a winding distortion removal process and transmission loss.

  Embodiments of the present invention will be described with reference to the drawings. In FIG. 1, 1 is a dispersion compensating optical fiber (DCF), 2 is a supply bobbin, 3 is a guide roller, 4 is a dancer roller, 5 is an AC servo motor, 6 is a tension meter, 7 is a control circuit, 8 is a coil bobbin, 9 is Rotation motors, 9a and 9b are drive shafts, 10 is a coiled fiber, 11a and 11b are resin supply means, 12 is resin, and 13 is a DCF coil.

  The DCF coil of the chromatic dispersion compensator is formed using, for example, a coil winding device as shown in FIG. In this coil winding device, the DCF 1 fed from the supply bobbin 2 is wound around the coil bobbin 8 through a plurality of guide rollers 3 and dancer rollers 4. The dancer roller 4 is controlled so that its rotational torque is controlled by the AC servo motor 5 so that the winding tension of the DCF in the coil bobbin 8 becomes a predetermined value described later. The winding tension of the DCF 1 is detected by a tension meter 6 provided in one of the plurality of guide rollers 3 and fed back to the control circuit 7.

  In the DCF coil 13, when the DCF 1 is wound on the coil bobbin 8, the fibers come into contact with each other, and loss due to a lateral pressure or microbending is likely to occur. For this reason, in the present invention, the coil bobbin 8 is wound with a winding tension lower than usual (20 g weight or more). For example, it is preferable to take up less than 10 g weight.

  FIG. 5 shows the relationship between the wavelength and the transmission loss (hereinafter simply referred to as loss) at the set winding tension of the DCF coil measured at room temperature (25 ° C.), and FIG. 6 shows the DCF measured at low temperature (−10 ° C.). The difference (loss change amount) between the wavelength and the loss at normal temperature (25 ° C.) in the coil winding tension is shown. The set winding tension indicates the winding tension that is set when the fiber is wound around the coil bobbin. The actual winding tension varies around the set winding tension value while winding around the coil bobbin. It is done.

  FIG. 5A shows loss characteristics when the optical fiber A for DCF (double clad fiber) is coiled. The winding pitch of the fiber is 0.7 mm, and the set winding tension of the fiber is 5 g weight, 10 g. It is the data which measured the relationship between the wavelength and loss when winding with a heavy weight and 30g weight. FIG. 5B shows loss characteristics of the DCF optical fiber B (triple clad fiber), which is data measured under the same conditions as the optical fiber A.

  According to FIG. 5, it can be seen that although there is a difference in the degree of loss depending on the type of optical fiber, the loss is reduced by making the winding tension low. Note that the loss is not much different due to the winding tension in the C-band wavelength region, but the difference in the magnitude of the loss due to the difference in winding tension becomes longer from the wavelength region of the L-band.

  In FIG. 6A, the DCF optical fiber A (double clad fiber) used for the measurement in FIG. 5A described above is coiled and held at a low temperature (−10 ° C.). It is data obtained by measuring the relationship between the wavelength and the loss. Similarly, FIG. 6 (B) shows a case where the DCF optical fiber B (triple clad fiber) used in the measurement of FIG. 5 (B) is coiled and held at a low temperature (−10 ° C.). It is the data which measured the relationship between the wavelength and loss. The loss is shown as a difference (loss change amount) from the loss at normal temperature (25 ° C.).

According to FIG. 6, in the low temperature state, the loss change increases at any winding tension from the C band region to the longer wavelength side, but the set winding tension is a low tension of 5 g weight and 10 g weight. Then, the loss increase rate is not so different, and the increase rate is not very large. However, when the set winding tension is as large as 30 g weight, the rate of increase in loss on the long wavelength side is larger than that of winding with a low tension.
Therefore, according to the measurement data of FIGS. 5 and 6 described above, it can be said that the lower the winding tension, the smaller the loss and the amount of change in loss when the temperature is changed, and it is preferable that the winding is preferably performed at a weight of 10 g or less. .

  However, when the winding tension on the coil bobbin is lowered, the winding coil tends to collapse. When unwinding occurs, loss due to microbending is likely to occur due to contact between fibers. In the present invention, as described above, the DCF is wound on the coil bobbin with a low tension, and a resin having adhesiveness is applied to the entire upper surface of the wound coiled fiber so that the coil of the fiber is applied to the coil bobbin. Hold and fix to maintain the shape.

  That is, as shown in FIG. 1 (B) or (C), after the coiled fiber 10 is wound around the coil bobbin 8 by the coil winding device of FIG. 1 (A), the resin supply means 11a is applied to the upper surface of the coil. , 11b gives adhesive resin 12. The resin can be applied to the coil upper surface 10a by application with a brush, a roll, a spatula or the like, or by spraying with a spray or the like. As will be described later, it is desirable that the resin be applied to the entire circumference of the upper surface of the coil and that an appropriate amount of resin be applied.

For example, as shown in FIG. 1B, the resin supply unit 11a applies the resin 12 with the resin supply unit 11a fixedly disposed, and the coil bobbin 8 around which the coiled fiber 10 is wound is disposed on the shaft 9a. And rotating with the rotation motor 9.
Also, as shown in FIG. 1C, the coil bobbin 8 side around which the coiled fiber 10 is wound is fixedly arranged, and the resin supply means 11b side is rotated by the rotating motor 9 using the shaft 9b. You may make it move around.

  FIG. 2 is a diagram illustrating an example of the DCF coil 13. In the figure, 8a is a body portion, 8b is a flange portion, 8c is a winding start end fiber drawing hole, 8d is a shaft support hole, 10a is a coil upper surface, 10b is a winding start end fiber portion, and 10c is a winding end fiber portion. Description of other reference numerals is omitted by using the reference numerals used in the description of FIG.

  FIG. 2A shows a state where the DCF is wound on the coil bobbin 8. The coil bobbin 8 is provided with flange portions 8b on both sides of the body portion 8a, and a winding start end fiber extraction hole 8c is provided in the inner diameter portion of one of the flange portions 8b to pull out the winding start end fiber portion 10b. A shaft support hole 8d is provided at the center. The body 8a is preferably formed of a plastic having a small thermal expansion coefficient. The flange portion 8b is formed of a lightweight metal such as aluminum. For example, the diameter of the coil bobbin 8 is about 120 mm in diameter of the body portion 8 a, 200 mm in diameter of the flange portion 8 b, and about 30 mm in width (width between the flange portions 8 b). The coil bobbin is wound with a DCF having a length of about 10 km.

  FIGS. 2B and 2C show a DCF coil 13 in which a resin 12 is applied to the coil upper surface 10 a of the coiled fiber 10 wound around the coil bobbin 8. The material of the resin 12 preferably has an adhesiveness with a small thermal expansion coefficient and a small shrinkage ratio after application. For example, an ultraviolet curable or room temperature curable silicone resin is used, and it is desirable that it is uniformly applied so as to cover the entire circumference of the upper surface 10 a of the coil and to adhere to the inner surface of the flange 8 b of the coil bobbin 8. . The resin 12 is applied by coating or spraying with the resin supply means 11a and 11b described with reference to FIG.

  About the application amount of resin 12, the evaluation result tested with the DCF coil 13 of the size mentioned above is shown in FIG. Samples 1 to 3 were prepared by using a silicone resin as the resin 12 and changing the coating amount to 5 g, 10 g, and 15 g. At this time, the silicone resin was applied by dropping the above amount of the silicone resin onto the coiled fiber 10 and spreading it with a spatula so as to have a uniform thickness. At this time, the number of rotations of the coil bobbin was less than 10 rpm. When the rotation speed was 10 rpm or more, the winding drum was displaced in the direction opposite to the rotation direction, the fiber was loosened or pulled, and the winding collapse or disconnection occurred.

  The application state of the resin is the DCF coil and resin of the above size, and when the application amount of the sample 1 is 5 g, the application thickness of the silicone resin is about 0.2 mm or less, and it is applied at several places near the buttock. There was a part that was not done, and the workability was not good due to the feeling that the coating amount was insufficient. When the coating amount of the sample 2 is 10 g, the coating thickness of the silicone resin is about 0.4 mm to 0.5 mm, there is no portion that is not coated including the edge of the bobbin, and the coating workability is also satisfactory. 10 to 12 g was appropriate. When the coating amount of the sample 3 is 15 g, the silicone resin coating thickness is about 0.7 mm to 0.8 mm, and there is no portion that is not applied including the bobbin edge as in the case of the sample 2. Although there was no problem in the workability of the coating, it was felt that the coating was applied more than necessary.

  Moreover, when the impact resistance test which drops from the height of 1 m in the state which packed the samples 1-3 mentioned above in the corrugated cardboard was implemented, the sample 1 was the silicone resin which existed at the edge of the collar part 8b of the coil bobbin 8 An uncoated part of the film started as a starting point and a gap was formed so as to tear. The fiber protruded from the gap, and the impact resistance test could not be satisfied. For samples 2 and 3, no change was observed in the silicone resin applied to the upper surface of the coil, and the impact resistance test could be cleared.

From the above results, it can be seen that the resin 12 is preferably applied so as to have a thickness of 0.4 mm or more from the coil upper surface 10a. This coating amount is a guideline when DCF is wound on a coil bobbin of the above size by 10 km, and varies depending on the winding amount of the coiled fiber 10 or the size of the coil bobbin 8. Further, when resins having different viscosities are used, there is a possibility that results satisfying the impact resistance test may be obtained even if the coating amount is smaller than this.
If the amount of the resin applied is too small, the surface on the coil is not sufficiently fixed, and a portion where the resin is not applied is generated, and the resin may tear due to stress concentration and may be unrolled. Therefore, a coating amount that provides a certain thickness from the upper surface of the coil is preferable. However, if the amount of application is too large, the cost is high, and depending on the thermal expansion coefficient of the resin, the coiled fiber 10 may be stressed.

  When winding the DCF with the coil bobbin 8, conventionally, since winding collapse occurs when the coil bobbin 8 is wound with low tension, an increase in loss is suppressed by widening the winding pitch. Japanese Patent Application Laid-Open No. H10-228667 discloses that the side pressure due to contact between adjacent fibers of the coil-wound fiber is reduced by increasing the winding pitch, thereby reducing the loss. However, if the winding pitch is increased too much, the length of the DCF that can be wound around the coil bobbin 8 is shortened, and it is necessary to increase the size of the coil bobbin 8 in order to wind a predetermined length. For example, when the winding tension is 5 g and the winding pitch is 0.7 mm, the space factor is 63%, but when the winding pitch is reduced to 0.3 mm, the space factor increases to 67%. That is, when the winding pitch is increased, the fiber that can be wound on the same bobbin is shortened. Further, when the winding pitch is increased, there is a problem that winding collapse is likely to occur.

In the present invention, as described above, the resin is applied to the entire circumference of the upper surface of the coil to prevent the coil from collapsing, so that it is possible to wind with a low tension and it is not necessary to increase the winding pitch too much. . The winding pitch P when the wire diameter of the DCF is d is preferably set to a value of “d <P ≦ 2d” in consideration of the space factor. Thereby, the space factor of a DCF coil can be improved and a chromatic dispersion compensator can be reduced in size. The fiber diameter of the DCF is 0.25 mm here.
Further, as disclosed in Patent Document 1, after the DCF is wound around the coil bobbin, the loss can be reduced by performing a winding distortion removing process. The winding distortion removal process is performed by a method such as a heat cycle process at −40 ° C. to + 80 ° C. or a vibration application process, for example.

  FIG. 8 shows test results showing the relationship between the number of winding distortion removal processes and the loss at each winding pitch. From this figure, although the initial loss differs between the winding pitch of 0.3 mm and the winding pitch of 0.7 mm, the difference in loss due to the difference in the winding pitch is eliminated by performing the winding distortion removal process. Further, it has also been found that the winding distortion removal process has no effect of improving the loss even if the number of processes is increased, and it is sufficient to perform the process at least once.

In addition, since the coil wound by low tension has a low space factor, after performing the winding distortion removal process, a gap is likely to be generated at the bobbin heel, thereby being easily broken. For this reason, it can be presumed that winding collapse is less likely to occur by applying a resin to the coil upper surface before the winding distortion removing process. However, at a winding pitch of 0.7 mm (P> 2d), the winding distortion removal treatment occurred both before and after applying the resin to the coil upper surface. On the other hand, when the winding pitch was 0.3 mm (P <2d) and 0.5 mm (P = 2d), the winding distortion was removed when the resin was applied before the resin was applied. In that case, no roll-up occurred.
Therefore, in the present invention, the winding pitch P of the dispersion compensating optical fiber is “d <P ≦ 2d” where d is the outer diameter of the dispersion compensating optical fiber, and the dispersion compensating optical fiber wound around the coil bobbin It is preferable to apply resin before carrying out the winding distortion treatment.

  FIG. 3 shows an outline of the manufacturing flow of the chromatic dispersion compensator described above. In step (1), the coiled fiber is wound around the coil bobbin by the winding device described with reference to FIG. In winding the coiled fiber, the DCF is wound with a margin slightly longer than a preset length. Next, in step (2), the dispersion value of the coiled fiber is measured in the state of FIG. Since the coil is wound long so as to exceed a predetermined dispersion value in advance, in the next step (3), the coil bobbin is rotated in the opposite direction to the winding, and the coil-wound fiber is fed out so that the dispersion value becomes a predetermined value. Adjust so that If the dispersion value does not become a predetermined value, the winding length adjustment in step (3) is performed again, and steps (2) and (3) are repeated.

  Next, proceeding to step (4), using the resin supply means described with reference to FIGS. 1B and 1C, the resin is applied to the entire circumference of the upper surface of the coiled fiber to prevent collapse. . Thereafter, in step (5), a winding distortion removal process due to a heat cycle or vibration is performed. Finally, the DCF coil manufactured as described above is housed in a housing, and a fiber lead or an optical connector is connected to obtain a chromatic dispersion compensator.

FIG. 4 shows a chromatic dispersion compensator manufactured by the manufacturing method of the present invention, in which 14 denotes a housing, 15 denotes a fiber lead, 16 denotes an optical connector, and 17 denotes a chromatic dispersion compensator.
The DCF coil 13 manufactured by the manufacturing method of the present invention has a configuration shown in FIGS. 2B and 2C via a fiber lead 15 in the winding start fiber portion and the winding end fiber portion, or directly to the optical connector 16. Are connected to each other and housed in the housing 14 to form a chromatic dispersion compensator 17.

DESCRIPTION OF SYMBOLS 1 ... Dispersion compensation optical fiber (DCF), 2 ... Supply bobbin, 3 ... Guide roller, 4 ... Dancer roller, 5 ... AC servo motor, 6 ... Tension meter, 7 ... Control circuit, 8 ... Coil bobbin, 8a ... trunk | drum, 8b DESCRIPTION OF REFERENCE SYMBOLS, 8c ... Winding start fiber drawing hole, 8d ... Shaft support hole, 9 ... Motor for rotation, 9a, 9b ... Drive shaft, 10 ... Coiled fiber, 10a ... Coil upper surface, 10b ... Winding start fiber part, DESCRIPTION OF SYMBOLS 10c ... Winding | ending terminal fiber part, 11a, 11b ... Resin supply means, 12 ... Resin, 13 ... DCF coil, 14 ... Housing | casing, 15 ... Fiber lead, 16 ... Optical connector, 17 ... Wavelength dispersion compensator.

Claims (4)

A method of manufacturing a chromatic dispersion compensator by winding a dispersion compensating optical fiber wound around a supply bobbin into a coil bobbin,
After winding the dispersion compensating optical fiber around the coil bobbin while controlling the winding tension to be less than 10 g, a resin is applied to the entire circumference of the fiber surface wound around the coil bobbin. A method of manufacturing a chromatic dispersion compensator, characterized in that the flange portion of the fiber and the entire circumference of the upper surface of the fiber are bonded and fixed.   2. The method of manufacturing a chromatic dispersion compensator according to claim 1, wherein the resin is applied while relatively rotating and moving the resin supply means and the coil bobbin.   The method for manufacturing a chromatic dispersion compensator according to claim 2, wherein a relative rotational speed difference between the resin supply means and the coil bobbin is 10 rpm or less.   The winding pitch P of the dispersion compensating optical fiber is set to “d <P ≦ 2d”, where d is the outer diameter of the dispersion compensating optical fiber, and the winding distortion processing of the dispersion compensating optical fiber wound around the coil bobbin. The method for manufacturing a chromatic dispersion compensator according to any one of claims 1 to 3, wherein the resin is applied before performing the step.

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