JP2003315564A - Optical fiber coil and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce winding tension and lateral pressure applied to an optical fiber. <P>SOLUTION: This optical fiber coil 1 is provided with: a lower collar 2; four pillars 3 erected in a circumferential shape on an inner surface of the lower collar 2, wherein at least a portion of them along an axial direction has a circular outer surface; a hollow cylindrical member 5 circumscribed on the circular outer surface of each of the pillars 3 and freely expandable and contractable along a radial direction; and an optical fiber 7 wound around the outer circumferential surface of the hollow cylindrical member 5. When a member for expansion and contraction is removed from the hollow cylindrical member 5 after the optical fiber 6 is wound around the outer circumferential surface of the hollow cylindrical member 5 while the member for expansion and contraction is inserted into the hollow part of the hollow cylindrical member 5, the hollow cylindrical member 5 is contracted along a radial direction so as to be circumscribed on the circular outer surface of each of the pillars 3. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispersion compensation fiber module (DCF).
The present invention relates to an optical fiber coil used in an optical functional module such as a module) and a manufacturing method thereof.

[0002]

2. Description of the Related Art An EDFA (Erbium Doped Fiber) constructed by using an optical fiber having a predetermined amplification characteristic or dispersion characteristic as an optical functional module for amplifying an optical signal transmitted through an optical fiber or for dispersion compensation. Amplifier) and DC
Optical function modules such as F modules have been put to practical use.

In an optical functional module using the above-mentioned optical fiber, an optical fiber having a predetermined length is required in order to realize the above-mentioned predetermined amplification characteristics and dispersion characteristics. Therefore, as shown in FIG. 13, an optical fiber 50 having a predetermined length is attached to a cylindrical bobbin barrel 52 of a bobbin 51.
Then, the input / output connectors 53 and 54 are attached to both ends of the bobbin 51 on which the optical fiber is wound. Then, the IN terminal 55 and the OUT terminal 56 are connected to the input / output connectors 53 and 54 of the bobbin 51 and housed and fixed in the small case 57, thereby realizing modularization.

In an optical functional module constructed by winding the above-mentioned optical fiber around a bobbin, it is necessary to make the length of the optical fiber sufficiently long in order to obtain desired characteristics (amplification characteristic and dispersion characteristic). There is also a demand for compact modules. Therefore, compact design is also required for the bobbin.

From the viewpoint of making the bobbin compact,
There is a demand to minimize the diameter of the bobbin barrel (barrel diameter) within a range that does not affect the reliability and does not increase the loss (bending loss) due to bending of the optical fiber.

[0006]

However, when the optical fiber is wound on a bobbin having a small diameter, the winding tension (external force acting on the optical fiber in the wound state) and the lateral pressure (winding) are applied to the optical fiber. The pressure acting on the adjacent portions of the fiber in the state and the pressure acting due to the deformation of the bobbin cylinder are applied. Then, due to the winding tension and the lateral pressure, a microbend loss (a loss due to a so-called microbend in which the axis of the optical fiber bends with a radius of curvature smaller than the core diameter) occurs in the optical fiber.

The microbend loss increases especially in the lower layer side optical fiber at the beginning of winding, and the wavelength characteristics and PMD (Polarized Mode Disperser) of the optical function module itself are increased.
ion; polarization mode dispersion)) and the transmission loss of the optical signal may increase.

In this respect, a method of attaching an uneven member to the outer circumference of the bobbin, winding the optical fiber on the uneven member, removing the uneven member from the bobbin after winding, and relaxing the winding tension, and a method of winding the optical fiber on the bobbin After wrapping
A method of reducing the lateral pressure by removing the bobbin from the optical fiber bundle has been considered.

However, in the former method, the optical fiber wound on the concavo-convex member is locally bent by the concavo-convex portion of the concavo-convex member, and the winding state of the optical fiber is disturbed. There is a possibility that the characteristics of the optical fiber may be deteriorated.

Further, in the latter method, when the bobbin is removed, there is a risk that the optical fiber may be damaged or that the winding state of the optical fiber may collapse. Furthermore, in order to prevent the collapse of the optical fiber, a special method / work for fixing the optical fiber itself is required, which is troublesome for the operator.

The present invention has been made in view of the above circumstances, and reduces winding tension and lateral pressure on an optical fiber without damaging the optical fiber and causing winding disorder or collapse. It is an object of the present invention to provide an optical fiber coil which can be manufactured and a manufacturing method thereof.

[0012]

According to the optical fiber coil of the first aspect of the present invention, the collar and the collar are erected on one surface of the collar in a circumferential shape and extend at least along the axial direction. At least three struts, some of which have arcuate outer surfaces, a hollow cylindrical member circumscribing the arcuate outer surfaces of each of the struts, and expandable and contractible in the radial direction, and an outer peripheral surface of the hollow cylindrical member. And an optical fiber wound around.

In the first aspect, the optical fiber is
The expansion / contraction member inserted into the hollow portion of the hollow cylindrical member presses at least two sets of mutually opposing portions on the inner peripheral surface of the hollow cylindrical member to expand the hollow cylindrical member in the radial direction, and It is wound around the outer peripheral surface of the hollow cylindrical member in a state of being separated from the arcuate outer surface of each strut, and in the hollow cylindrical member, the expansion / contraction member is the hollow cylindrical member after the optical fiber is wound. It is configured to contract along the radial direction and circumscribe the arcuate outer surface of each of the columns when removed from the column.

According to the method for manufacturing an optical fiber coil in the second aspect of the present invention, the step of preparing the collar and at least three columns having at least a part along the axial direction having an arcuate outer surface. And a step of circumferentially standing the at least three or more columns on one surface of the collar, and a hollow cylindrical member that is expandable / contractible along the radial direction is prepared. A step of arranging so as to circumscribe the arcuate outer side surface of each of the columns, and preparing an expansion / contraction member insertable into the hollow portion of the hollow cylindrical member, and inserting the expansion / contraction member into the hollow portion of the hollow cylindrical member. Then, a step of pressing at least two sets of mutually opposing portions on the inner peripheral surface of the hollow cylindrical member to expand the hollow cylindrical member in the radial direction, an optical fiber is prepared, and the optical fiber is Radial direction A step of winding the outer circumferential surface of the hollow cylindrical member which is expanded along, has been extracted the scaling member is contracted along the hollow cylindrical member in the radial direction after the optical fiber is wound.

BEST MODE FOR CARRYING OUT THE INVENTION An optical fiber coil and a method for manufacturing the same according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic perspective view showing the optical fiber coil 1 according to the embodiment of the present invention in which an upper flange described later is removed, and FIG. 3 is a plan view of the fiber coil 1. FIG. 3 is a sectional view of the optical fiber coil 1 shown in FIG. 2, taken along the line III-III.

As shown in FIGS. 1 to 3, the optical fiber coil 1 includes a lower collar 2 having a circular cross section orthogonal to the axial direction.
And 4 erected on the inner surface of the lower flange 2 in parallel with each other along the axial direction and in a circumferential shape, and having a substantially circular cross section (diameter (φ): 10 mm) orthogonal to the axial direction. And the column 3 of.

As each of the columns 3, a pin or a cylinder molded of a material having a small linear expansion coefficient due to temperature change is used.

The optical fiber coil 1 is erected on the inner surface of the lower collar 2 via an interposing member 4 such as rubber or resin, and circumscribes the outer peripheral surface of the pillar 3 so as to surround it, and A hollow cylindrical member 5 that is expandable and contractable along the radial direction is provided.

Further, the optical fiber coil 1 includes an optical fiber 6 wound around the outer peripheral surface of the hollow cylindrical member 5 in a layered and annular shape along, for example, the radial direction and the axial direction, and the upper end of the hollow cylindrical member 5. It is provided with an interposing member 4 provided on the periphery and an upper flange 7 which is detachably attachable to the upper ends of the optical fibers 6.

As shown in FIG. 4, the hollow cylindrical member 5 is provided with a plurality of slits 10 formed in the outer peripheral surface thereof at a plurality of locations along the axial direction.
Can be expanded and contracted in the radial direction by the plurality of slits 10.

As shown in FIG. 2, the lower collar 2 has a plurality of inner walls extending concentrically with the hollow cylindrical member 5 with the columns 3 in between and extending in a cross shape (for example, a cross shape) along the radial direction. Through holes 15a1 and 15a2 are formed. The length of each of the through holes 15a1 and 15a2 along the radial direction of the hollow cylindrical member 5 is, for example, 1 or more than the diameter of the hollow cylindrical member 5.
mm longer.

Next, the manufacturing process of the optical fiber coil 1 of this embodiment will be described, and the operation of the optical fiber coil 1 will be described.

First of all, the worker is to insert the through holes 15a1 and 1a.
Four columnar expansion / contraction members 20a1 that can be fitted into 5a2
Prepare 20a4. Then, the worker inserts the prepared expansion / contraction members 20a1 to 20a4 into the hollow portion of the hollow cylindrical member 5, the expansion / contraction members 20a1 and 20a2 into the through hole 15a1, and the expansion / contraction members 20a3 and 20a4 into the through hole 15a2, respectively. Get in.

Subsequently, the operator inserts the expansion / contraction members 20a1, 20a2 and 20a3 and 20a4 fitted in the through holes 15a1 and 15a2, respectively, toward the tip portions of the corresponding through holes 15a1 and 15a2 along the radial direction. To move.

At this time, each through hole 15a1 and 15a
The radial length of the hollow cylindrical member 5 in 2 is 1 mm longer than the diameter of the hollow cylindrical member 5. Therefore, by moving the expansion / contraction members 20a1, 20a2 and 20a3 and 20a4 to the extreme ends of the through holes 15a1 and 15a2, the expansion / contraction members 20a1, 20a.
2 through hole 15a in the inner peripheral surface of the hollow cylindrical member 5
1 corresponding to each other, and the expansion / contraction member 2
By 0a3 and 20a3, the portions of the inner peripheral surface of the hollow cylindrical member 5 that correspond to the through holes 15a2 and that face each other can be pressed outward.

In this embodiment, the hollow cylindrical member 5 can be expanded and contracted in the radial direction by the plurality of slits 10 formed in the outer peripheral surface along the axial direction. Therefore, the expansion / contraction members 20a1, 20a2
By pressing the inner peripheral surface of the hollow cylindrical member 5 by the expansion / contraction members 20a3 and 20a4, the hollow cylindrical member 5 can be separated from the outer peripheral surface of each of the columns 3 to expand the diameter by about 1 mm.

Next, the operator inserts an optical fiber 6 having a predetermined strip length corresponding to the intended use of the optical fiber coil 1 in the radial direction and the axial direction with respect to the outer peripheral surface of the hollow cylindrical member 5. Winding in a layered and annular shape along the
(See FIG. 7).

At this time, since the diameter of the hollow cylindrical member 5 is expanded by 1 mm, the expanded diameter of the hollow cylindrical member 5 becomes the winding diameter of the optical fiber 6.

When the optical fiber 6 having a predetermined length is wound around the outer peripheral surface of the hollow cylindrical member 5 in this manner, the operator inserts all the expansion / contraction members 20a1-20a4 into the through hole 1
5a1 and 15a2 and the hollow portion of the hollow cylindrical member 5 are pulled out.

By pulling out the expansion / contraction members 20a1-20a4, the hollow cylindrical member 5 contracts in the radial direction until it comes into contact with the outer peripheral surfaces of the columns 3, as shown in FIG.

That is, the expansion / contraction members 20a1-20a4.
As a result of the removal of the pressing force from the hollow cylindrical member 5 and contraction of the hollow cylindrical member 5 in the radial direction, the entire optical fiber 6 wound in an annular shape (in particular, the inner diameter side (expansion / contraction members 20a1 to 20a4.
The external force (side pressure) and the winding tension with respect to the side on which the pressing force of the hollow cylindrical member 5 has acted are reduced and alleviated.

In this way, the optical fiber coil 1 shown in FIGS. 1 to 3 can be manufactured.

Here, in order to verify the effect obtained from the manufactured optical fiber coil 1, the optical fiber coil 1 is manufactured.
The wavelength loss characteristic of was measured. As shown in FIG. 9, the resulting wavelength loss characteristics have improved flatness in the corresponding wavelength band and improved loss wavelength characteristics as compared with the wavelength loss characteristics of the conventional optical fiber coil. I found out.

Further, as a result of performing a vibration and impact test on the optical fiber coil 1, the winding of the optical fiber 5 did not collapse, and no change was observed in the optical characteristics after the test.

By connecting the input and output terminals to both ends of the fiber of the optical fiber coil 1 manufactured as described above through connectors and storing and fixing it in a small case (not shown), the modularized optical fiber coil 1 is obtained. Can be provided.

As described above, according to this embodiment,
By pressing the inner peripheral surface of the expandable / contractible hollow cylindrical member 5 with the expansion / contraction members 20a1 to 20a4, the hollow cylindrical member 5 can be separated from the outer peripheral surfaces of the support columns 3 and expanded in diameter. Then, the optical fiber 6 is wound around the outer peripheral surface of the expanded hollow cylindrical member 5, and after the winding is completed, the expansion / contraction members 20a1 to 20a4 are removed from the hollow portion of the hollow cylindrical member 5 to form a hollow cylindrical member. 5 can be contracted in the radial direction until it comes into contact with the outer peripheral surface of each column 3.

As a result, the winding diameter of the optical fiber 6 can be increased, and the external force (lateral pressure) and the winding tension with respect to the entire optical fiber 6 (in particular, the inner diameter side thereof) can be reduced or relaxed.

Therefore, it is possible to prevent the deterioration of the wavelength characteristic and the PMD characteristic of the optical fiber coil 1 due to the microbend loss caused by the winding tension and the lateral pressure. In particular, the winding tension acts more strongly on the inner diameter side of the optical fiber 6, but the winding tension and lateral pressure at the inner diameter portion can be particularly reduced. Therefore, it is particularly effective for preventing the deterioration of the wavelength characteristic and the PMD characteristic.

Further, in this embodiment, since the four columns 3 are arranged inside the hollow cylindrical member 5, the strength of the optical fiber coil 1 can be maintained. further,
The contraction of the hollow cylindrical member 5 can be stopped at a position corresponding to its appropriate diameter.

Further, in the present embodiment, the optical fiber 6 can be wound (wound) on the hollow outer peripheral surface of the hollow cylindrical member 5. For this reason, it is possible to prevent local bending and winding disorder with respect to the wound optical fiber 6, and avoid occurrence of loss such as microbend loss.

In particular, in this embodiment, the hollow cylindrical member 5 is still left in the optical fiber coil 1 after the optical fiber 6 is wound. Therefore, it is possible to maintain the strength against the vibration and the shock acting on the optical fiber coil 1, and it is possible to prevent the occurrence of the winding collapse due to the vibration and the shock.

Further, unlike the conventional case, the winding tension and the lateral pressure acting on the optical fiber 6 can be reduced without using a complicated member such as an uneven member, so that the cost for manufacturing the optical fiber coil is reduced. be able to.

In this embodiment, the number of columns is four, but the present invention is not limited to this, and the number of columns is three or more, which is the minimum number that allows a plurality of columns to be circumferentially arranged. I wish I had it. Further, in the present embodiment, the columns are arranged at predetermined intervals, but they may be arranged at different intervals.

Further, in the present embodiment, a plurality of slits are bored in the hollow cylindrical member along the axial direction in order to make the hollow cylindrical member expandable and contractible in the radial direction, but the present invention is not limited to this. However, the hollow cylindrical member may have any structure as long as the hollow cylindrical member is configured to be expandable and contractible in the radial direction, such as being manufactured by a material that can be expanded and contracted in the radial direction.

Further, in this embodiment, the number of columns (4
However, the present invention is not limited to this, and the number of expansion / contraction members can be increased according to the number of columns.

For example, as shown in FIGS. 10 and 11, when eight pillars 3a are erected on the inner surface of the lower collar 2 in parallel with each other along the axial direction and in a circumferential shape, On the other hand, four through holes 15b1 to 15b4 that are concentric with the hollow cylindrical member 5 and that intersect radially along the radial direction and that extend radially are formed on the inner surface of the pillar 3 with the pillar 3 interposed therebetween.

Then, the through holes 15b1 to 15b4
Eight columnar expansion / contraction members 20b1-20b that can be fitted into
8 is prepared, and the prepared expansion / contraction members 20b1 to 20b8 are used as hollow portions of the hollow cylindrical member 5 and through holes 15b1 to 15b.
Insert / remove (insert / remove) to / from 4. As a result, the cylindrical member 5 can be expanded / contracted in the radial direction, as in the case of the four columns and the eight expansion / contraction members described above.

Furthermore, in the present embodiment, each pillar has a substantially circular cross section along the axial direction, but the present invention is not limited to this. It suffices that a part of the outer surface of each of the columns along the axial direction has an arc shape. For example, as shown by reference numeral 3b in FIG. 12, it has a part of the arc surface along the axial direction. The cross section orthogonal to each other may have a fan shape or the like.

[0049]

As described above, according to the optical fiber coil and the method for manufacturing the same of the present invention, the hollow cylindrical member is expanded by pressing the inner peripheral surface of the expandable / contractible hollow cylindrical member. In the diameter-diametered state, the optical fiber is wound around the outer peripheral surface of the expanded hollow cylindrical member, and after the winding is completed, the expansion / contraction member is removed from the hollow portion of the hollow cylindrical member to form the hollow cylindrical member. It is contracted along the radial direction until it comes into contact with the outer peripheral surface of each column.

Therefore, when winding the optical fiber, the winding diameter is expanded, and after the winding is completed,
By contracting the hollow cylindrical member, the external force (lateral pressure) and the winding tension with respect to the entire optical fiber (in particular, the inner diameter side thereof) can be reduced or relaxed.

Therefore, it is possible to prevent the deterioration of the wavelength characteristic and the PMD characteristic of the optical fiber coil due to the microbend loss caused by the winding tension and the lateral pressure.

[0052]

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a state in which an upper flange described later is removed from an optical fiber coil 1 according to an embodiment of the present invention.

FIG. 2 is a plan view of the optical fiber coil with the upper collar shown in FIG. 1 removed.

FIG. 3 is a sectional view of the optical fiber coil 1 shown in FIG.

FIG. 4 is a perspective view showing the hollow cylindrical member shown in FIG.

FIG. 5 is a perspective view corresponding to FIG. 1, showing a state in which an expansion / contraction member is inserted into the hollow cylindrical member to expand the diameter of the hollow cylindrical member, and the optical fiber is wound up.

FIG. 6 is a plan view showing the optical fiber coil in the state shown in FIG.

7 is a cross-sectional view of the optical fiber coil shown in FIG. 6, taken along the line VII-VII.

FIG. 8 is a plan view corresponding to FIGS. 2 and 6 showing the optical fiber coil when the expansion / contraction member is removed from the state shown in FIGS. 5 to 7;

FIG. 9 is a graph showing the result of comparing the wavelength loss characteristic of the optical fiber coil according to the present embodiment with that of a conventional optical fiber coil.

FIG. 10 is a plan view of the optical fiber coil according to the modified example of the present embodiment with the upper flange removed.

11 is a sectional view of the optical fiber coil 1 shown in FIG. 10, taken along the line XI-XI.

FIG. 12 is a perspective view showing a schematic configuration of a support column according to a modified example of the present embodiment.

FIG. 13 is a diagram showing a schematic configuration of an optical fiber coil housed and fixed in a case.

[Explanation of symbols]

1 Optical fiber coil 2 lower tsuba 3 props 4 Insertion member 5 Hollow cylindrical member 6 optical fiber 7 Upper Tsuba 10 slits 15a1, 15a2, 15b1 to 15b4 through holes 20a1 to 20a4, 20b1 to 20b8 Expansion / contraction member

Continued front page    (72) Inventor Shiro Nakamura             2-6-1, Marunouchi, Chiyoda-ku, Tokyo             Kawa Electric Industry Co., Ltd. F-term (reference) 2H038 AA24 CA35

Claims (5)

[Claims] 1. A brim, at least three pillars that are erected circumferentially on one surface of the brim, and have at least a portion along the axial direction that has an arcuate outer surface, and each pillar. An optical fiber coil, comprising: a hollow cylindrical member circumscribing an arcuate outer surface of the hollow cylindrical member and expandable / contractible in a radial direction; and an optical fiber wound around an outer peripheral surface of the hollow cylindrical member. . 2. The hollow optical fiber according to claim 1, wherein at least two sets of mutually facing portions on the inner peripheral surface of the hollow cylindrical member are pressed by the expansion / contraction member inserted in the hollow portion of the hollow cylindrical member. Is expanded along the radial direction and is wound around the outer peripheral surface of the hollow cylindrical member in a state of being separated from the arcuate outer surface of each of the columns, and the hollow cylindrical member is wound with the optical fiber. Later when the expansion and contraction member is removed from the hollow cylindrical member,
The optical fiber coil according to claim 1, wherein the optical fiber coil is configured to contract in a radial direction and circumscribe the arcuate outer surface of each of the columns. 3. The optical fiber coil according to claim 1, wherein the hollow cylindrical member is provided with a plurality of slits formed on the outer peripheral surface thereof at a plurality of positions along the axial direction. 4. The flange has a plurality of through holes extending on one surface thereof so as to intersect with each other along the radial direction of the hollow cylindrical member, and the through holes extend along the radial direction of the hollow cylindrical member. The optical fiber coil according to any one of claims 1 to 3, wherein the length is longer than the diameter of the circular portion of the end portion of the hollow cylindrical member on the side of the through hole. 5. A step of preparing a collar, and at least three pillars having at least a part of an arcuate outer surface along the axial direction are prepared, and the at least three pillars are provided in one of the collars. A step of circumferentially standing on the surface, a step of preparing a hollow cylindrical member capable of expanding and contracting along the radial direction, and arranging the hollow cylindrical member so as to circumscribe the arcuate outer surface of each of the columns. , Preparing an expansion / contraction member insertable into the hollow portion of the hollow cylindrical member, inserting the expansion / contraction member into the hollow portion of the hollow cylindrical member, and facing at least two sets of the inner peripheral surface of the hollow cylindrical member to each other. A step of pressing the portion to be expanded in the radial direction of the hollow cylindrical member; preparing an optical fiber; and winding the optical fiber around the outer peripheral surface of the expanded hollow cylindrical member in the radial direction. Step Method of manufacturing an optical fiber coil characterized by comprising the steps of: deflating along the hollow cylindrical member radially withdrawn the scaling member after the optical fiber winding.