JP7087330B2 - Fiber optic holder - Google Patents

Description

The present disclosure relates to optical fiber holders.

Due to wavelength multiplexing, digital coherence, multi-channel, etc., a plurality of optical fibers are connected to one optical member. The pitch of the optical waveguide of the optical member to be connected is fixed, and it is necessary to connect the optical fiber accurately according to this pitch. In recent years, higher pitch accuracy (positional accuracy of fiber spacing) is required due to the miniaturization of optical members and the progress of silicon photonics.

Conventionally, a method of aligning and holding optical fibers using a V-groove substrate has been used (see, for example, Patent Document 1). However, in this method, since the fiber is sandwiched between the V-groove substrate and the lid and adhered to each other, it takes time and effort, and it is difficult to reduce the size. On the other hand, in recent years, an optical fiber holder in which a plurality of optical fibers are preliminarily aligned and held by using a glass capillary tube (glass capillary) or the like has been studied (see, for example, Patent Document 2). However, in the method described in Patent Document 2, although the optical fibers can be adjacent to each other, it is difficult to arrange the optical fibers at a certain interval.

In order to solve these problems, attempts have been made to create a fiber array by providing a plurality of through holes in the glass capillary. However, as described in Patent Document 2, a through hole clearance is required to insert the optical fiber.

If an optical fiber having a diameter of 125 μm is inserted, the fiber core pitch accuracy is required to be 1 μm or less (submicron). In order to meet this requirement, it is necessary to precisely control the clearance of the through hole and the pitch accuracy of the through hole.

For this reason, it is necessary to precisely control the clearance and spacing of the through holes of the glass capillary, which is very expensive. Moreover, if an error exceeding the allowable error occurs in the clearance and the interval, the glass capillary cannot be used, and a large yield loss occurs.

Japanese Patent No. 4056143 Japanese Patent No. 4019428

Therefore, it is an object of the present disclosure to provide an optical fiber holder having a structure capable of accurately controlling the arrangement of optical fibers without lowering the yield.

The optical fiber holders of the present disclosure are
Capillaries with multiple through holes and
An optical fiber inserted into each through hole of the capillary,
It is an optical fiber holder equipped with
The cross-sectional shapes of the plurality of through holes in the cross section perpendicular to the longitudinal direction of the optical fiber differ in the axial ratio of the long axis to the short axis.
The major axes of the plurality of through holes are substantially parallel.

Since the optical fiber holder of the present disclosure has a space in the through hole in the long axis direction, it is easy to arrange the optical fiber in the through hole. Further, since the optical fiber holder of the present disclosure has a different aspect ratio of the cross-sectional shape of the through hole in which the optical fiber is arranged, the movement of the optical fiber in the short axis direction of the through hole is restricted after the optical fiber is arranged in the through hole. At the same time, it is possible to align the through hole in the long axis direction. Therefore, according to the present disclosure, it is possible to provide an optical fiber holder having a structure capable of accurately controlling the arrangement of optical fibers without lowering the yield.

A schematic configuration of the optical fiber holder according to the present disclosure is shown. The first example of the cross section of the optical fiber holder is shown. An example of the cross-sectional shape of the through hole is shown. A second example of a cross section of an optical fiber holder is shown. An example of the arrangement of the optical fiber in the through hole is shown. An example of a cross section of an optical fiber holder having a D-cut shape in the capillary is shown. An example of a cross section of an optical fiber holder having a double D-cut shape in the capillary is shown. An example of a cross section of an optical fiber holder having a two-dimensional arrangement of optical fibers is shown. It is explanatory drawing of the method of measuring the permeation time of an adhesive in a capillary. An example of measuring the penetration rate of the adhesive with respect to the axial ratio of the long axis and the short axis of the cross-sectional shape of the through hole is shown. FIG. 10 shows an enlarged view of the permeation rate of the adhesive at an axial ratio of around 1.0000 shown in FIG.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The present disclosure is not limited to the embodiments shown below. Examples of these implementations are merely examples, and the present disclosure can be implemented in various modified and improved forms based on the knowledge of those skilled in the art. In addition, the components having the same reference numerals in the present specification and the drawings shall indicate the same components.

(First Embodiment)
FIG. 1 is a schematic configuration diagram of an optical fiber holder according to the present embodiment. The optical fiber holder according to the present embodiment includes a capillary 21 provided with a plurality of through holes 22-1 and 22-2, and optical fibers 11-1 and 11-2 inserted into each through hole 22 one by one. And.

FIG. 2 is a cross-sectional view showing an example of the present embodiment. The cross section shown in FIG. 2 shows a cross section perpendicular to the longitudinal direction of the optical fibers 11-1 and 11-2. The cross-sectional shape of the through hole 22 of the present embodiment has a different axial ratio between the long axis and the short axis. Thereby, the present disclosure restricts the movement of the optical fibers 11-1 and 11-2 in the minor axis direction of the through holes 22-1 and 22-2, while restricting the movement of the through holes 22-1 and 22-2 in the major axis direction. Allows the movement of optical fibers 11-1 and 11-2 in.

FIG. 3 shows an example of the cross-sectional shape of the through hole. The cross-sectional shape of the through hole 22 of the present embodiment is different between the major axis DL in the major axis direction and the minor axis DS in the minor axis direction. For example, an ellipse as shown in FIG. 3 (a), a shape whose major axis direction is linear and both ends in the major axis direction are arcuate as shown in FIG. 3 (b), FIG. 3 (c). An elliptical shape as shown in FIG. 3D and a rectangle as shown in FIG. 3D can be exemplified. The short diameter DS can be any value in which the optical fibers 11-1 and 11-2 can be arranged in the through holes 22-1 and 22-2.

The gap between the through hole 22 and the optical fiber 11 is filled with an adhesive. Therefore, it is preferable that the cross-sectional shape of the through hole 22 is a curved shape having no corners through which the adhesive easily flows. For example, in the case of a rectangle as shown in FIG. 3D, it is preferable that the corners are rounded.

As shown in FIG. 2, the fiber core pitch PAs of the optical fibers 11-1 and 11-2 are adjusted to predetermined values. Here, the optical fibers 11-1 and 11-2 are arbitrary optical fibers, and include a single mode fiber, a multimode fiber, and a polarization holding fiber. The composition of the optical fibers 11-1 and 11-2 and the capillary 21 is arbitrary, but glass can be used, for example. The fiber core pitch PA shall be an arbitrary value determined by the specifications of the optical fiber holder required by the types of optical fibers 11-1 and 11-2 and the capillary 21, as well as the pitch of the optical waveguide to which the optical fiber is connected. Can be done.

In the through holes 22-1 and 22-2 of the present disclosure, the major axis directions of the through holes 22-1 and 22-2 are substantially parallel. As described above, in the present disclosure, in order to align the movable direction of the optical fiber 11-1 in the through hole 22-1 and the movable direction of the optical fiber 11-2 in the through hole 22-2, the fiber uses the directions of the long axes AL1 and AL2. By adjusting the core pitch PA, it is possible to provide a highly accurate optical fiber holder. The shapes of the through holes 22-1 and 22-2 depend on the specifications of the capillary 21. Therefore, the major axes AL1 and AL2 may be parallel within the specifications of the capillary 21.

The major axis directions of the through holes 22-1 and 22-2 can be set in any direction. For example, as shown in FIG. 2, the long axis AL1 of the through hole 22-1 and the long axis AL2 of 22-2 are arranged on a substantially straight line AA. In this case, since the movement of the optical fibers 11-1 and 11-2 in the vertical direction with respect to the straight line AA is restricted, the pitch adjustment of the optical fibers 11-1 and 11-2 becomes easy.

Here, the straight line AA is a straight line connecting the centers of the through holes 22-1 and 22-2. The center of the through holes 22-1 and 22-2 is, for example, the intersection of DL / 2 and DS / 2 shown in FIG. The center positions of the through holes 22-1 and 22-2 depend on the specifications of the capillary 21. Therefore, the center positions of the through holes 22-1 and 22-2 are not necessarily geometrically arranged on the straight line AA, but may be arranged in the vicinity of the straight line AA.

As shown in FIG. 4, the directions of the major axis AL1 of the through hole 22-1 and the major axis AL2 of 22-2 may be substantially perpendicular to the straight line AA. In this case, as shown in FIG. 4, if the optical fibers 11-1 and 11-2 are arranged at the center of the through holes 22-1 and 22-2, the minimum pitch PH equal to the pitch PH of the through holes 22-1 and 22-2. It becomes the fiber core pitch PA of. On the other hand, as shown in FIG. 5, when the optical fibers 11-1 and 11-2 are arranged at the ends of the through holes 22-1 and 22-2, the maximum pitch PH is longer than that of the through holes 22-1 and 22-2. It becomes the fiber core pitch PA of. In this way, the fiber core pitch PA can be adjusted for the major axes AL1 and AL2 in any direction with respect to the straight line AA.

The cross-sectional shape of the capillary 21 is not limited to a circular shape, and may be any shape. For example, it may be a polygon such as a quadrangle, or a circle or a part of the polygon may be provided with protrusions or notches.

6 and 7 show first and second examples of the cross-sectional shape of the capillary 21. The first example of the cross-sectional shape of the capillary 21 is a D-cut shape in which the capillary 21 includes a flat portion 23. A second example of the cross-sectional shape of the capillary 21 is a double D-cut shape in which the capillary 21 includes flat portions 23 and 24.

The straight line AA and the flat portion 23 are substantially parallel, and the distance DA between the straight line AA and the flat portion 23 has a predetermined value. As a result, in the optical fiber holder shown in FIGS. 6 and 7, the flat portion 23 can be used as a reference surface for joining with the optical member, and the optical fiber holder can be mounted. In addition to the flat portion 23 or in addition to the flat portion 23, a reference portion having an arbitrary shape may be provided in the cross-sectional shape of the capillary 21.

Here, the center positions of the through holes 22-1 and 22-2 are not necessarily geometrically arranged on the straight line AA. Therefore, the straight line AA obtained by using the center positions of the through holes 22-1 and 22-2 and the flat portion 23 do not necessarily have to be geometrically parallel, and the specifications of the optical fiber holder according to the present disclosure. It suffices if they are parallel within the range specified by.

The method for manufacturing the optical fiber holder according to the present disclosure is arbitrary. For example, a capillary 21 is prepared, and optical fibers 11-1 and 11-2 are arranged in the through holes 22-1 and 22-2. Next, the gaps between the through holes 22-1 and 22-2 are filled with an adhesive and cured. Curing of the adhesive is performed, for example, by using photocuring. In this step, the positions of the optical fibers 11-1 and 11-2 are adjusted before filling the adhesive or curing the adhesive.

In the present embodiment, an example is shown in which two optical fibers 11-1 and 11-2 are arranged on a straight line AA, but the present disclosure is not limited to this. For example, three or more optical fibers may be arranged on the straight line AA. Further, the arrangement of the optical fibers is not limited to the one-dimensional arrangement, and may be a two-dimensional arrangement of two or more rows. For example, as shown in FIG. 8, the optical fibers 11-1 and 11-2 are arranged on the straight line AA1 of the distance DA1 from the flat portion 23, and the optical fibers 11-3 and 11-2 are arranged on the straight line AA2 of the distance DA2 from the flat portion 23. It may be a two-dimensional arrangement in which 11-4 is arranged and the optical fiber 11-5 is arranged on the straight line AA3 of the distance DA3 from the flat portion 23.

(Second embodiment)
If the clearance of the through hole of the capillary 21 is increased, there arises a problem that the position accuracy cannot be obtained. On the other hand, when the clearance becomes small, it becomes difficult for the resin for fixing the fiber to enter the gap between the through hole and the optical fiber, which causes a problem that productivity is lowered. Therefore, the inventors examined an appropriate axial ratio between the major axis DL in the major axis direction and the minor axis DS in the minor axis direction, that is, DL / DS.

FIG. 9 shows a schematic diagram of the measurement system used in this embodiment. A capillary 21 in which an optical fiber is arranged in the through hole 22 is prepared, and after the adhesive 62 supplied from the needle 61 and the end of the capillary 21 come into contact with each other, a liquid passing through a gap in the through hole 22 is placed at a predetermined position due to a capillary phenomenon. The time to reach was measured. As the adhesive 62, one having a viscosity of 400 mPa · s and one having a viscosity of 290 mPa · s were used as those generally used for fixing the optical fiber to the through hole 22.

FIG. 10 shows an example of the penetration rate of the adhesive. The horizontal axis shows the axis ratio, that is, DL / DS, and the vertical axis shows the penetration time of the adhesive per 1 mm. When the axial ratio DL / DS was 1.0000, the permeation rate was 232 sec / mm. On the other hand, by making the axial ratio DL / DS larger than 1.0000, the permeation rate gradually decreased. As described above, it can be seen that the permeation time of the adhesive into the through hole 22 can be greatly shortened by having different axial ratios. On the other hand, when the axial ratio DL / DS is 1.2000 or more, the effect of shortening the permeation time becomes small. In addition, it is not easy to form through holes having greatly different axial ratios. Therefore, the axial ratio DL / DS is preferably larger than 1.0000 and smaller than 1.2000.

In the manufacturing process of the optical fiber holder, it is necessary to infiltrate the adhesive 62 into the through hole 22 in which the optical fiber is arranged at an appropriate time. This time depends on the length of the capillary 21, but is preferably 50 sec or less per 1 mm.

FIG. 11 shows an enlarged view of the region _AC near the axial ratio DL / DS 1.000. As shown in this enlarged view, when the axial ratio DL / DS was 1.0024, the permeation rate of any of the adhesives decreased to 50 sec / mm or less. Further, when the axial ratio DL / DS was 1.0075, the permeation rate of any of the adhesives decreased to 40 sec / mm or less. Further, when the axial ratio DL / DS was 1.0160, the permeation rate of any of the adhesives decreased to 30 sec / mm or less. In particular, it was found that the permeation rate can be reduced to 30 sec / mm or less by setting the axial ratio DL / DS to 1.0070 by using the adhesive 62 having a viscosity of 290 mPa · s.

As described above, in the present disclosure, the adhesive 62 can be permeated into the through hole 22 in which the optical fiber is arranged in an appropriate time because the axial ratio of the cross-sectional shape of the through hole 22 is different. Therefore, in the present embodiment, the optical fiber holder according to the present embodiment can reduce the clearance of the through hole without lowering the productivity.

This disclosure can be applied to the information and telecommunications industry.

11-1, 11-2: Optical fiber 21: Capillary 22-1, 22-2: Through hole 61: Needle 62: Adhesive

Claims (1)

Capillaries with multiple through holes and
An optical fiber inserted into the through hole one by one, and
It is an optical fiber holder equipped with
The cross-sectional shape of the plurality of through holes in the cross section perpendicular to the longitudinal direction of the optical fiber has a linear portion having a different axial ratio of the major axis to the minor axis and extending in the major axis direction of the through hole.
The major axes of the plurality of through holes are parallel to each other ,
The long axis of the plurality of through holes is perpendicular to the straight line connecting the centers of the plurality of through holes.
The short diameter of the through hole determined by the distance between the straight portions has a value in which the optical fiber can be arranged.
The composition of the capillary and the optical fiber is glass.
The optical fiber is fixed in the through hole by infiltrating the adhesive from the end of the capillary into the through hole.
The axial ratio is 1.016 or more and less than 1.2.
Fiber optic holder.

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