JPH10170745A - Optical fiber connector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber connector with high reliability that neither increases connection loss nor deteriorate reflection attenuation quantity characteristic even in a temperature cycle. SOLUTION: A pressure block 19, which presses optical fibers 29 made to butt against each other in an optical fiber guide groove from above, is so constituted that its perpendicular sectional shape parallel to the optical fiber guide groove is made nearly concave, trapezoid, or triangular. Then, when a pressing force is applied to the pressure block 19 from above, the pressure block 19 deforms elastically to generate compressive stress nearby the bottom surface of the pressure block 19 touching the head peak part of the optical fiber 29, and an abutting force always operates on both the optical fibers 29 which are made to about against each other. Further, a slit is formed in the pressure surface of the pressure block 19 at right angles to the optical fiber guide groove and then the pressure block 19 becomes easy to deform, so that the downward pressing force is converted into the compressive stress nearby the pressure surface of the pressure block 19 with efficiency.

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 for connecting an optical fiber.

[0002]

2. Description of the Related Art When an optical fiber is connected, an optical fiber connector is used in which a pair of optical fibers are connected to each other in an optical fiber guide groove (also referred to as "mechanical splice").

FIG. 8A is an external perspective view showing a conventional example of an optical fiber connector, and FIG. 8B is a sectional view of the optical fiber connector shown in FIG. Yes (Japanese Unexamined Patent Publication
-239510).

The optical fiber connector 1 has an optical fiber (not shown) in an optical fiber guide groove 3 formed on a substrate 2 and abuts against a pressing surface of a plate 4 for pressing the top of the optical fiber. The crystal alloy layer 5 is provided.

[0005]

However, in the above-mentioned conventional optical fiber connector, the material of the plate 4 for pressing the fiber is limited, but the shape is not limited.

When a temperature cycle is applied to the optical fiber connector after connecting the optical fibers using such an optical fiber connection, there is a problem that optical characteristics such as an increase in connection loss and a decrease in return loss are deteriorated. there were.

Hereinafter, the mechanism of deterioration of the optical characteristics will be described.

An optical fiber connector that abuts optical fibers in an optical fiber guide groove and presses the optical fiber with a plate from above has a structure in which the optical fiber is sandwiched between the plate and the optical fiber guide groove from above and below.

Here, when the material of the substrate on which the optical fiber guide groove is formed is different from that of quartz, which is the material of the optical fiber, the respective members have different coefficients of linear expansion.

Generally, the material of the optical fiber is quartz.
And its linear expansion coefficient is about 0.5 × 10 ^-6(/ ° C)
You. The material of the substrate and the pressing plate can be various ceramics, gold
Metal or plastic, the coefficient of linear expansion is
It is larger than an optical fiber. For this reason, optical fiber
When the temperature rises after connection, each member thermally expands and the optical fiber
The bus also thermally expands in the axial direction.

Here, since the thermal expansion of the upper and lower members of the optical fiber is larger than that of the optical fiber, a tensile force acts on the optical fiber, and a separating force is generated at the abutting portion of the optical fiber. Normally, grease for refractive index matching is applied to the optical fiber abutting surface, but since the grease has poor fluidity, bubbles may be generated in the grease when a separating force is generated. When bubbles are generated, connection loss increases due to Fresnel reflection and refraction at the bubble interface, leading to deterioration of optical characteristics such as a decrease in return loss.

[0012] Therefore, an object of the present invention is to solve the above-mentioned problems, to increase connection loss even during a temperature cycle,
An object of the present invention is to provide a highly reliable optical fiber connector that does not cause deterioration in return loss characteristics.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a method for abutting a pair of optical fibers in an optical fiber guide groove having a substantially V-shaped cross-section formed on a substrate. In an optical fiber connector that presses the portion from above the substrate by pressing means to align and fix the optical axis of the optical fiber, the pressing means is formed such that a vertical cross section parallel to the optical fiber guide groove has a substantially concave shape. And a biasing member for biasing the pressure block toward the substrate.

In the present invention, in addition to the above configuration, it is preferable that a wedge-shaped indenter is provided between the pressing block and the urging member to perform the pressing.

Further, the present invention relates to a method of forming a substantially V-shaped substrate on a substrate.
A pair of optical fibers are butted in an optical fiber guide groove having a U-shaped cross section, and the abutting portion of the optical fibers is pressed from above the substrate by pressing means to align and fix the optical axis of the optical fiber, The pressing means includes a pressing block having a substantially trapezoidal or triangular vertical cross-section parallel to the optical fiber guide groove, and a reverse recess having a vertical cross-section substantially parallel to the optical fiber guide groove and disposed on the pressing block. And a biasing member for biasing the pressing block toward the substrate side so as to hold the opposing slope of the pressing block.

In addition to the above configuration, in the present invention, it is preferable that at least one slit is formed on the fiber pressing surface of the pressing block in a direction orthogonal to the optical fiber guide groove.

According to the present invention, the pressing block for pressing the optical fibers abutted in the optical fiber guide groove from above is provided so that the vertical cross section parallel to the optical fiber guide groove has a substantially concave, trapezoidal or triangular shape. By applying a pressing force to the pressing block from above, the pressing block is elastically deformed, and a compressive stress is generated near the pressing surface of the pressing block in contact with the top of the optical fiber, that is, near the bottom surface of the pressing block. A butt force is always applied to both generated and butted optical fibers. For this reason,
The optical fiber connection is less susceptible to temperature cycling.

Further, by forming a slit in the pressing surface of the pressing block in a direction orthogonal to the optical fiber guide groove, the pressing block is easily deformed, and the pressing force from above is reduced by the compression in the vicinity of the pressing surface of the pressing block. It is efficiently converted to stress.

[0019]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is an external perspective view showing an embodiment of an optical fiber connector according to the present invention, and FIG. 2 is an exploded perspective view of the optical fiber connector shown in FIG.

In the center of the surface of the substrate 10 shown in FIG. 2, a groove 11 having a substantially V-shaped cross section for a bare fiber is formed.
A groove 12 having a U-shaped cross section capable of accommodating the optical fiber together with the covering material is formed near both ends of the optical fiber.

Reference numeral 14 denotes a cover plate, and a rectangular through hole 15 for inserting a pressing block is formed in the center of the cover plate 14. On both ends of the cover plate 14, grooves 16 having a semicircular cross section are formed at positions corresponding to the grooves 12 of the semicircular cross section of the substrate 10. By fixing the cover plate 14 from above the substrate 10 by bonding or the like, guide holes 18 (see FIG. 1) for inserting optical fibers are formed on both side surfaces of the substrate.

Reference numeral 19 denotes a pressing block having a substantially concave cross section. A plurality of slits 20 are formed in the pressing block 19 in a direction orthogonal to the optical fiber guide groove 11. Two convex strips 21 and 22 are formed on both sides of the opening on the upper surface of the pressing block 19. Such a pressing block 19 is inserted into the through hole 15 such that the bottom surface side where the slit 20 is formed faces down.

A spring receiving plate 23 is mounted on the pressing block 19, and a coil spring (a coil spring in the figure, but may be a leaf spring) is disposed on the spring receiving plate 23.

The upper portion of the coil spring 24 is pressed by a spring stopper 25 having a crank cross-sectional shape.
By fixing the lower part of 5 to the cover plate 14, an optical fiber connector 26 as shown in FIG. 1 is formed. The spring receiving plate 23, the coil spring 24, and the spring stopper 25 constitute an urging member 27. The pressing means 17 is composed of the pressing block 19 and the urging member 27.

The connection process of optical fibers using the optical fiber connector shown in FIG. 1 will be described.

First, the pressing block 19 is lifted up, and the optical fiber 29 having the tip cut at a right angle and coated with grease 28 for refractive index matching is inserted from both the guide holes 18 of the optical fiber connector 26 into the substrate 10. Butts at the center of the box without any gaps. After the optical fibers 29 are butted,
When the pressing block 19 is released, the pressing block 19 presses the fiber core at the fiber connection portion by the elastic force of the coil spring 24. By performing the alignment and the fixing, the connection between the optical fibers 29 is completed.

Next, the operation of the optical fiber connector according to the present invention will be described with reference to FIG.

FIG. 3 shows B of the optical fiber connector shown in FIG.
FIG. 4 is a cross-sectional view taken along line B.

When the pressing block 19 is placed near the butting portion 29a of the optical fiber 29, the top 2
A pressing force is applied to 9b from above by a coil spring 24. Since the cross-sectional shape of the pressing block 19 is substantially concave, when a downward pressing force (in the direction of arrow D) acts on the ridges 21 and 22, a tensile stress is applied to the upper part of the pressing block 19 in the longitudinal direction of the optical fiber. (In the direction of arrow E), and a compressive stress (in the direction of arrow F) occurs below the pressing block 19. The compressive stress becomes maximum near the contact surface between the pressing block 19 and the top 29b of the optical fiber 29. As a result,
Since a butting force (in the direction of arrow G) always acts on the connection portion 29a of the optical fiber 29, high reliability without increasing connection loss or deteriorating return loss characteristics even during a temperature cycle. Can be obtained.

FIG. 4 is an external perspective view showing another embodiment of the present invention.

The difference from the embodiment shown in FIG. 1 is that a wedge-shaped indenter is provided between the pressing block and the urging member to press.

In the optical fiber connector 30 shown in FIG. 3, the pressing block 31 has a concave cross section, and is substantially wedge-shaped by a biasing member 27 comprising a spring receiving plate 23, a coil spring 24 and a spring stopper 25. At 32, the opening of the pressing block 31 is pushed open to load. Although the spring receiving plate 23 and the indenter 32 are formed integrally in the figure, they may be formed separately.

In this optical fiber connector 30, the butting force acts on both optical fibers 29 at the contact surface between the bottom surface of the pressing block 31 and the optical fibers 29, so that the connection loss increases even during the temperature cycle, as described above. , And high reliability without deterioration of return loss characteristics.

As described above, in the optical fiber connector using the butt connection, the butt force is always applied to the optical fibers at any temperature due to the elastic deformation of the pressing blocks 19 and 31, so that the connection loss increases or the reflection occurs during the temperature cycle. An optical fiber connector having excellent temperature cycle resistance can be obtained without deterioration of the attenuation characteristic.

FIG. 5 is an external perspective view showing another embodiment of the optical fiber connector according to the present invention, and FIG. 6 is an exploded perspective view of the optical fiber connector shown in FIG. The same reference numerals are used for members similar to those in the embodiment shown in FIG.

The difference from the embodiment shown in FIG. 1 is that the pressing means 40 comprises a pressing block 41 and a pressing block 41.
And an urging member 43 for urging the substrate 10 to hold the opposing slopes of the pressing block 41 with the inverted concave block 42 disposed above the pressing block 41.

By fixing the substrate 10 and the cover plate 14 from above the substrate by bonding or the like, guide holes 18 for inserting optical fibers are formed on both side surfaces of the substrate 10.

The pressing block 41 has a substantially trapezoidal vertical cross section parallel to the optical fiber guide groove, and a plurality of slits 44 formed in a direction perpendicular to the optical fiber guide groove. Such a pressing block 41 is inserted into the through hole 15 of the cover plate 14 such that the bottom surface side on which the slit 44 is formed faces downward.

On the pressing block 41, an inverted concave block 42 whose vertical cross section parallel to the optical fiber guide groove has a substantially inverted concave shape is disposed. On the inverted concave block 42, a coil spring (in FIG. (It is a coil spring, but may be a leaf spring.)
24 is arranged. Spring stopper 25 with crank cross section
Press the upper part of the coil spring 24 with the cover plate 14
The optical fiber connector 4 as shown in FIG.
5 are formed.

Next, the operation of the optical fiber connector shown in FIG. 5 will be described with reference to FIG.

FIG. 7 shows C of the optical fiber connector shown in FIG.
FIG. 4 is a sectional view taken along line C of FIG.

By pressing the inverted concave block 42 from above in the direction of arrow H, the pressing block 41 having a trapezoidal cross-sectional shape is held, and the pressing block 41 is elastically deformed so as to be substantially in the longitudinal direction of the fiber (arrow I). Direction), a compressive stress is generated. Therefore, the top 29b of the fiber 29
The pressing block 41 contracts on the lower surface of the pressing block 41 which is in contact with, and a force always acts in a direction (arrow J direction) where the two optical fibers 29 abut against each other due to friction with the top part 29b.

Further, since the slit 44 is formed on the pressing surface of the pressing block 41 in a direction orthogonal to the optical fiber guide groove, the pressing surface of the pressing block 41 is efficiently contracted by the pressing force from above the pressing block 41. Can be done.

As described above, according to the present invention, the fiber butt force always acts at any temperature due to the elastic deformation of the pressing block 41. An optical fiber connector having excellent characteristics can be obtained.

Incidentally, even after the optical fibers are once connected to each other, the optical fibers can be attached and detached any number of times. Further, in the present embodiment, the optical fiber has a single core. However, by forming a plurality of guide grooves in parallel, it is possible to easily increase the number of optical fibers.

[0047]

In summary, according to the present invention, the following excellent effects are exhibited.

Since the fiber butting force always acts due to the elastic deformation of the fiber pressing block, a highly reliable optical fiber connector that does not increase the connection loss or deteriorate the return loss characteristic even during a temperature cycle. Offer can be realized.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing an embodiment of an optical fiber connector according to the present invention.

FIG. 2 is an exploded perspective view of the optical fiber connector shown in FIG.

3 is a longitudinal sectional view of the optical fiber connector shown in FIG. 1 in the longitudinal direction of the optical fiber.

FIG. 4 is an external perspective view showing another embodiment of the present invention.

FIG. 5 is an external perspective view showing another embodiment of the optical fiber connector of the present invention.

6 is an exploded perspective view of the optical fiber connector shown in FIG.

FIG. 7 is a cross-sectional view of the optical fiber connector shown in FIG. 5, taken along line CC.

8A is an external perspective view showing a conventional example of an optical fiber connector, and FIG. 8B is a cross-sectional view of the optical fiber connector shown in FIG.

[Explanation of symbols]

 Reference Signs List 10 substrate 11 optical fiber guide groove 17 pressing means 19 pressing block 20 slit 27 urging member 29 optical fiber

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshinobu Kurosawa 5-1-1 Hidakacho, Hitachi City, Ibaraki Pref.

Claims (4)

[Claims] 1. A pair of optical fibers are butted in an optical fiber guide groove having a substantially V-shaped cross section formed on a substrate,
In an optical fiber connector that presses the abutting portion of the optical fiber from above the substrate by pressing means to align and fix the optical axis of the optical fiber, the pressing means has a vertical cross section substantially parallel to the optical fiber guide groove. An optical fiber connector comprising: a pressing block formed in a concave shape; and an urging member for urging the pressing block toward the substrate. 2. The optical fiber connector according to claim 1, wherein a wedge-shaped indenter is provided between the pressing block and the urging member to perform the pressing. 3. A pair of optical fibers are butted in an optical fiber guide groove having a substantially V-shaped cross section formed on a substrate.
In an optical fiber connector that presses the abutting portion of the optical fiber from above the substrate by pressing means to align and fix the optical axis of the optical fiber, the pressing means has a vertical cross section parallel to the optical fiber guide groove. A substantially trapezoidal or triangular pressing block and an inverted concave block arranged on the pressing block and having a vertical cross section parallel to the optical fiber guide groove and having a substantially inverted concave shape, sandwiching opposed slopes of the pressing block. And an urging member for urging the substrate toward the substrate. 4. A fiber pressing surface of the pressing block,
4. The optical fiber connector according to claim 1, wherein at least one slit is formed in a direction orthogonal to the optical fiber guide groove.