JPH11211928A - Optical fiber connector - Google Patents

Abstract

(57) [Problem] To provide an optical fiber connector that can be easily polished, is excellent in mass productivity, and can be reduced in cost. The bare optical fiber 3a is placed on the V-groove 1a and the coating is removed.
It is fixed at. The end surface 2a of the pressing member is connected to the end surface 1 of the substrate.
Move backward from c. When the end face is obliquely polished, only the end face of the substrate need be polished without polishing the pressing member, so that the polishing time can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber connector used for connecting an optical fiber to an optical device such as an optical waveguide.

[0002]

2. Description of the Related Art As an optical fiber connector to which an optical fiber is fixed, which is used for connecting an optical fiber to an optical device such as an optical waveguide, a covering mounting formed with a step from a V-groove portion at the front and a V-groove at the rear. There is known one using a substrate provided with a portion and a pressing member for pressing the bare optical fiber aligned with the V-groove.

FIG. 6 is a view for explaining such an optical fiber connector. FIG. 6A is a perspective view before an optical fiber is arranged, and FIG. 6B is a state in which the optical fiber is gripped. FIG. 6 (C) is a longitudinal sectional view through the center of the optical fiber. In the figure, 1 is a substrate, 1a is a V-groove, 1b is a coating placement portion, 1c is an end face, 2 is a pressing member, 2a is an end face, 3
Is an optical fiber, 3a is a bare optical fiber, 3b is a coating portion, 4
Is an adhesive. In FIG. 6B, illustration of the adhesive is omitted.

[0006] As shown in FIG. 6 (A), a V-groove 1 a is formed on the upper surface in front of the substrate 1, and a coating mounting portion 1 b is formed with a step behind it. The bare optical fiber exposed by removing the coating of the optical fiber 3 is arranged in the V-groove 1a, and as shown in FIG. The adhesive 4 is injected around the bare optical fiber between the member 2 and around the optical fiber placed on the coating placing part, and the optical fiber 3 is fixed. Thereafter, the end face of the front end is polished for connection with a waveguide or the like. Usually, it is polished obliquely in order to reduce reflected return light.

FIG. 7 shows another example of the optical fiber connector, schematically showing the optical fiber connector described in Japanese Patent Application Laid-Open No. 6-51155.
FIG. 7A is a perspective view before an optical fiber is arranged, and FIG.
FIG. 7 is a perspective view showing a state where the optical fiber is gripped, and FIG. 7C is a longitudinal sectional view centered on the optical fiber. In the figure, the same parts as those in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted. In this example, the pressing member is configured to also cover the covering portion 3b, and the covering portion 3b has a step corresponding to the outer diameter of the covering portion 3b.
b.

An example of connection between an optical fiber connector and a waveguide will be described. FIG. 8 is a view for explaining an example of a use state of the optical fiber connector.
8A is a side view, and FIG. 8B is a plan view. In addition, in order to make it easy to see the inside, it is illustrated by thin lines. In the figure, 11,
11 'is an optical fiber connector, 12.12' is an eight-core optical fiber ribbon, 13 is a waveguide chip, and 14 is a waveguide. Both end surfaces of the waveguide chip 13 are polished at an inclination angle of, for example, 8 °, are aligned from both sides, and the optical fiber connectors 11 and 11 ′ are bonded. Waveguide chip 13
, Four sets of couplers are formed by a waveguide 14, and eight ports on both sides are respectively connected to tape-shaped optical fiber cores 12, 12 'of optical fiber connectors 11, 11' on both sides, Performs multiplexing and demultiplexing.

As described above, when returning light is reduced, for example, when an optical fiber connector is connected to a waveguide, the front end face is polished obliquely. Also, in the case where the end face of the optical connector is perpendicular to the axis of the optical fiber and the butt connection is performed, the end face of the optical connector and the end face of the optical fiber are made the same plane, and the accuracy of the butt is improved. To increase the height, the end face of the optical connector is polished.

In the following description, the case where the end face of the optical connector is polished obliquely will be described. However, the present invention includes a case where the end face is polished at right angles.

As described with reference to FIGS. 6 and 7, the coating is removed to expose the bare optical fiber 3b, and the bare optical fiber 3b is aligned with the V-groove of the substrate 1 having the V-groove. After pressing and bonding with the adhesive 4, the end face is polished.

The end face of the optical fiber connector to be polished is such that the end face 1c of the substrate 1 and the end face 2a of the pressing member 2 are on the same plane, and when the end faces are polished, both end faces must be polished simultaneously. . The pressing member 2 is transparent because an ultraviolet-curable adhesive is used for bonding and fixing to the waveguide, and
In order to improve the reliability of the module due to a temperature change, a material having an expansion coefficient equivalent to that of a waveguide or a fiber is used. Examples of such a material include glass and transparent ceramic. On the other hand, the substrate 1 is made of a relatively soft material such as silicon or a resin molded body.

Although the end face is polished so as to form a slope of about 8 ° for connection to the waveguide, the pressing member 2 is hard, so that the polishing time becomes longer or the grindstone wears faster. No, there was a problem that the cost would be high. It also took time to find the optimal conditions for polishing.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an optical fiber connector which can be easily polished, has excellent mass productivity, and can be manufactured at low cost. It is assumed that.

[0013]

According to a first aspect of the present invention, there is provided a substrate having a V-groove for aligning an optical fiber from which a coating has been removed, and a pressing member for aligning the optical fiber by pressing the optical fiber into the V-groove. In the optical fiber connector having the member, an end surface of the pressing member is located inside the end surface of the substrate and is located at a position where the end surface is not polished.

According to a second aspect of the present invention, in the optical fiber connector according to the first aspect, the substrate is made of a material having a lower hardness than the pressing member.

According to a third aspect of the present invention, in the optical fiber connector according to the first or second aspect, silicon is used as the substrate.

According to a fourth aspect of the present invention, in the optical fiber connector according to the first or second aspect, a resin molded body is used as the substrate.

[0017]

1 and 2 are views for explaining a first embodiment of an optical fiber connector according to the present invention. FIG. 1A is a perspective view of a substrate, and FIG. 1) is a perspective view showing a state where an optical fiber is gripped, FIG. 1 (C) is a longitudinal sectional view centering on the optical fiber, and FIG. 2 is a sectional view showing a state where an end face is polished. In the figure, 1 is a substrate, 1a is a V-groove, 1b is a coating placement portion, 1c is an end face, 2 is a pressing member, 2a is an end face, 3
Is an optical fiber, 3a is a bare optical fiber, 3b is a coating portion, 4
Is an adhesive. In FIG. 1B, illustration of the adhesive is omitted.

As shown in FIG. 1A, a V-groove 1a is formed on the upper surface in front of the substrate 1, and a coating mounting portion 1b is formed with a step behind it. The bare optical fibers exposed by removing the coating of the optical fiber 3 are arranged in the V-groove 1a, and as shown in FIG. The adhesive 4 is injected around the bare optical fiber between the member 2 and around the optical fiber placed on the coating placing part, and the optical fiber 3 is fixed. For example, the outer diameter of the bare optical fiber 3a is 1
The outer diameter of the coating portion 3b is 250 μm. The step between the center of the bare optical fiber 3a mounted on the V-groove 1a and the upper surface of the coating mounting portion 1b is about 125 μm.
As shown in FIG. 6 (C), in the optical fiber connector, the center of the optical fiber is positioned so as to be substantially straight from the bare optical fiber 3a placed on a to the covering portion 3b.

As shown in FIGS. 1B and 1C, the pressing member 2 has its end face 2a located inside the end face 1c of the substrate 1 and is bonded while pressing the bare optical fiber 3a. Is done. In the drawing, the position of the rear end face opposite to the front end face 2a of the pressing member 2 is such that the rear end face is aligned with the rear end face of the V-groove. In this case, the length of the pressing member 2 is shorter than the length of the V groove. However, the rear end surface of the pressing member 2 may be short of the rear end surface of the V-groove, or may protrude backward from the rear end surface of the V-groove.

Although the manufacturing process will be described together with specific examples, the present invention is not limited to specific numerical values. The case where an optical fiber having an outer diameter of 125 μm and a coating outer diameter of 250 μm of a bare optical fiber is used will be described as an example.

The substrate 1 shown in FIG. 1A has a thickness of 1 mm.
And one or more V-grooves formed in the silicon substrate. The V-groove 1a can be easily and accurately manufactured by processing with a dicer. The shape of the V-groove 1a is such that when the bare optical fiber 3a is placed in contact with both side surfaces of the V-groove 1a,
The angle and the depth are such that the bare optical fiber projects upward about 20 μm above the upper surface of the V-groove forming surface. Coating mounting part 1
b is 300 μm with respect to the central axis of the bare optical fiber.
It is.

A description will be given with reference to FIGS.
The bare optical fiber 3a is exposed by removing the coating on one or a plurality of tips of the single-core optical fiber, and the bare optical fiber 3a is aligned in the V premises. At the same time, the bare optical fiber 3a is pressed by the pressing member 2 made of quartz glass. Is pressed, and the bare optical fiber 3a is fixed in the V premises so as to be in contact with the pressing member 2. Next, the adhesive 4 is poured to bond the substrate 1, the pressing member 2, and the bare optical fiber 3 a, and to cover the optical fiber mounted on the cover mounting portion 1 b formed as a step portion behind the substrate 1. Part 1b
Is adhered to the substrate 1. The end surface 2a of the pressing member 2 is
About 200 μm from the end face 1c of the first embodiment.

The optical fiber gripped by the optical fiber connector is not limited to a single-core optical fiber as described above, but may be a tape-like optical fiber in which a plurality of optical fibers are arranged in parallel to form a common coating. Optical fibers can also be used.

The front end of the substrate 1 on which the members and the optical fibers are fixed by the adhesive 4 is polished obliquely. Usually, the angle is about 8 ° to reduce the reflected return light. Since the pressing member 2 is retracted from the end face 1c of the substrate 1, it is not polished as shown in FIG. For this reason, only the soft silicon substrate is shaved, and the processing time for polishing is short.

FIG. 3 shows an example of the mode of use of the optical fiber connector manufactured as described above. In the figure, 5, 5 '
Is an optical fiber connector, 6, 6 'are tape-shaped optical fibers, and 7 is a waveguide chip. Optical fiber tape 6,
6 'uses an eight-core tape-shaped optical fiber in this example. The waveguide chip 7 was a 1 × 8 branch waveguide. Light is input from one optical fiber of the tape-shaped optical fiber 6, light passing through the branch waveguide of the waveguide chip 7 is received by the eight-core optical fiber connector 5 ', and the optical axes of the waveguide and the optical fiber are aligned. Adjust and align for maximum power. After the alignment, an adhesive having a matching refractive index is poured into the connection portion between the waveguide chip 7 and the optical fiber connectors 5 and 5 ', and the mixture is cured and fixed, whereby a waveguide module can be manufactured.

FIG. 4 is a longitudinal sectional view of the optical fiber connector according to a second embodiment of the present invention, illustrating the center of the optical fiber. In the figure, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, the end face 1c of the substrate 1 is polished in a direction opposite to that of the first embodiment. In a specific example, in FIG. 1C showing a state before the polishing step, the end surface 2a of the pressing member 2 is
It is set back by 400 μm from the end face 1 c of the substrate 1.

FIG. 5 is a view for explaining a third embodiment of the optical fiber connector according to the present invention. FIG. 5A is a perspective view of a substrate and a pressing member, and FIG. FIG. In the figure, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted. 1d is a side wall. In this embodiment, a resin molded body is used for the substrate 1. When a resin molded body is used as the material of the substrate 1, polishing is easy, and a complicated shape can be easily manufactured as long as it can be molded. As shown in FIG. 5A, it is easy to integrally mold the side wall 1d. Side wall 1
By setting the front end face of d as a regulation position when the pressing member 2 is mounted, the pressing member 2 can be accurately positioned, and the position at which the end surface 2a of the pressing member 2 retreats from the end face 1c of the substrate 1 can be easily set. is there. In addition, by making it a resin molded body,
Many V-groove substrates can be manufactured in a short time. Glass particles are mixed with the resin for molding so that the expansion coefficient of the glass can be approximated to that of the optical fiber or the waveguide, and accurate molding can be performed.

Although it has been described that the substrate 1 is made of a material having relatively low hardness, such as silicon or a resin molded product, which is easy to polish, the present invention is not limited to the glass or the glass having the same hardness as the pressing member. Ceramic may be used. Hard materials require time for polishing, but by mounting the pressing member backward and not being polished, the polishing area can be reduced, so that the polishing time is shorter than in the conventional case where the pressing member is also polished. Can be shortened.

When silicon is used for the substrate 1, K
The substrate may be manufactured by wet etching with an OH solution or the like. When a resin molded body is used for the substrate 1, the groove is V
Even if it is not a shape, it is sufficient if the fiber is processed so as to be aligned with desired accuracy, such as a trapezoid or a circle.

When an ultraviolet-curing adhesive is used as the adhesive used for assembling or connecting to the waveguide, the material of the pressing member 2 is preferably a material transparent to ultraviolet rays. When 1 is a transparent material, the pressing member 2
May be an opaque material. As the waveguide, a polymer waveguide, a semiconductor waveguide, or the like may be used in addition to the silica-based waveguide.

As the adhesive for fixing the optical fiber, the pressing member, and the like to the substrate, a thermosetting adhesive, a hot melt, and the like can be used in addition to an ultraviolet curable adhesive that can be quickly cured. Given the stress on the optical fiber,
It is preferable that the Young's modulus, expansion coefficient, and cure shrinkage ratio are as small as possible. The adhesive used for connection with the waveguide is preferably an ultraviolet curable adhesive in which the refractive index of the waveguide and the optical fiber are matched, but a thermosetting adhesive can also be used.

[0032]

As is apparent from the above description, according to the first aspect of the present invention, since only the substrate is polished, the polishing time can be reduced and the wear rate of the grindstone can be reduced. Is also easily established. Further, by retracting the pressing member, it is not necessary to make the pressing member transparent, and the range of material selection can be widened.

According to the second aspect of the present invention, the end face is easily polished because the substrate is made of a material having a lower hardness than the pressing member.

According to the third aspect of the present invention, there is an effect that an etching technique can be applied. According to the fourth aspect of the present invention, mass productivity is excellent and cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a view for explaining a first embodiment of an optical fiber connector of the present invention, wherein (A) is a perspective view of a substrate,
(B) is a perspective view of a state in which the optical fiber is gripped, and (C) is a longitudinal sectional view centered on the optical fiber.

FIG. 2 is a cross-sectional view of a state where the end face of FIG. 1 is polished.

FIG. 3 is an explanatory diagram of an example of a mode of use of the optical fiber connector of the present invention.

FIG. 4 is a longitudinal sectional view centering on an optical fiber for explaining a second embodiment of the optical fiber connector of the present invention.

5A and 5B are views for explaining a third embodiment of the optical fiber connector according to the present invention, wherein FIG. 5A is a perspective view of a substrate and a pressing member, and FIG. It is a perspective view.

6A and 6B are views for explaining an example of a conventional optical fiber connector, in which FIG. 6A is a perspective view before an optical fiber is arranged, FIG. 6B is a perspective view in a state where the optical fiber is gripped,
(C) is a longitudinal sectional view through the center of the optical fiber.

7A and 7B are views for explaining another example of the conventional optical fiber connector, in which FIG. 7A is a perspective view before an optical fiber is arranged, FIG. 7B is a perspective view in a state where the optical fiber is gripped,
(C) is a longitudinal sectional view through the center of the optical fiber.

8A and 8B are diagrams for explaining an example of a use state of the optical fiber connector, wherein FIG. 8A is a side view and FIG. 8B is a plan view.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 1a ... V groove, 1b ... Coating mounting part, 1c ... End surface, 1d ... Side wall, 2 ... Pressing member, 2a ... End surface, 3 ... Optical fiber, 3a ... Bare optical fiber, 3b ... Coating part, 4 …adhesive.

Claims (4)

[Claims] 1. An optical fiber connector comprising: a substrate having a V-groove for aligning an optical fiber having a coating removed thereon; and a pressing member for aligning the optical fiber by pressing the optical fiber into the V-groove. Is an inner side of the end face of the substrate and is located at a position where the end face is not polished. 2. The optical fiber connector according to claim 1, wherein the substrate is made of a material having a lower hardness than the pressing member. 3. The optical fiber connector according to claim 1, wherein said substrate is made of silicon. 4. The optical fiber connector according to claim 1, wherein a resin molded body is used as the substrate.