JPH0453609Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a connector plug that is attached to a multi-core optical fiber that is a collection of a plurality of optical fibers.

(Prior Art and Problems) First, the structure of the optical fiber to which the connector is attached will be described.

FIG. 6a is a side view showing the structure of one single fiber wire, where 1 is an optical fiber and 2a is a single fiber wire in which the optical fiber 1 is covered with a coating. FIG. 6b is a sectional view taken along line A-A' in FIG. 6a. FIG. 7a is a side view showing the structure of a tape core in which a plurality of optical fibers are assembled, in which 1 is an optical fiber, and 2b is a core in which a plurality of optical fibers 1 are assembled and then covered with a coating. This is called a tape core wire. FIG. 7b is a sectional view taken along line BB' in FIG. 7a.

The dimensions of commonly used tape cores are, for example, 0.45 mm in thickness, 1.6 mm in width, and 0.3 mm in optical fiber arrangement pitch, and the coating material is an ultraviolet curing resin.

Next, a multi-core connector attached to the tape core shown in FIG. 7 will be described. As the first conventional example, Nagasawa, Satake, Ashiya, "Simple assembly technology of multi-core optical connectors" 1985 IEICE General Conference
2255, Patent Application No. 45400 ``Waterproof Optical Fiber Multi-Fiber Connector with Built-in Single-Fiber Wire Collection Part'' and Utility Application No. 1983-
FIG. 8 shows the structure of the multi-fiber optical connector disclosed in No. 29997, "Optical Multi-Fiber Connector Core Assembly Jig."

FIG. 8 is a perspective view showing the structure of a core component of a multi-core optical connector. 101 is a core ferrule, 102 is a core lid, 103 is a small diameter hole for positioning an optical fiber, 104 is a hole for a guide pin, and 105 is a hole for injection of adhesive. Assembly is performed in the following order: applying adhesive to the core ferrule 101, inserting an optical fiber, curing the adhesive by heating, and polishing the end face of the core using a polishing machine.

The disadvantages of the first conventional example will be described below.

This assembly method uses an adhesive to fix the optical fiber, so although the time required for the adhesive to harden is shortened by using a heating machine or the like, it takes a long time of 10 to 15 minutes and is poor in workability. Additionally, a heating machine, assembly jig, etc. are required. Next, it takes about 5 minutes to polish the end face, so it cannot be said that assembly is done in a short time.It takes about 30 minutes to assemble one connector plug. It has drawbacks such as not being able to be assembled on time.

As a second conventional example, the structure will be described using Utility Application No. 60-198856 "Optical Connector Plug" as an example.

Figure 9 is used for the single core wire shown in Figure 6,
It is an optical connector of a simple assembly type that does not use adhesive, and 201 has a small diameter hole for positioning the optical fiber;
202 is a core, 203 is a coupling nut that connects with the adapter, 204 is a spring, 205 is a house tube that engages with a part of the core 202 and holds it inside, 206 is the rear end of the core 202 207 is a clamping sleeve, 20
7a is the caulking part, 207b is the clamp sleeve 2
07 is the outer peripheral male thread, 208 is the clamp nut,
Reference numeral 208a indicates an inner peripheral female threaded portion of the clamp nut 208, and reference numeral 209 indicates a flexible pipe made of nylon. To assemble the connector plug, after stress-breaking the tip of the optical fiber 1 of the single-fiber wire 2a to obtain an end surface through which light can easily pass, the single-fiber wire 2a is inserted into the small diameter hole 201 for optical fiber positioning of the core 202. The coated portion of the single-fiber wire 2a is assembled by rotating the clamp nut 208 of the caulking mechanism 206 provided at the rear end of the core 202 and caulking and fixing it. The assembly time required for this is 2 to 3 minutes, and it has the advantage of being easy to assemble.

Problems in applying this second conventional example to a tape core will be described below.

The caulking portion 207a can uniformly caulk the single fiber 2a in a circularly symmetrical manner, and stable fixation is possible, but with this structure, it is not possible to stably fix a tape fiber having a rectangular cross section. . Another disadvantage is that the process of inserting the optical fiber from which the coating has been removed through the narrow caulking section is difficult to perform.

(Means for Solving the Problems) The present invention provides a mechanism for caulking and holding the core wires with a flat plate without using adhesive, as a method for fixing the core wires of a multi-core optical fiber tape inserted into a connector plug. It is an object of the present invention to provide a connector plug for multi-core optical fibers, which has the following features and can be assembled in a short time. By using this connector plug, it is possible to recover in a short time from failures such as disconnection accidents of optical cables using tape core wires.

The multi-core optical fiber connector plug of this invention solves the problems of the conventional tape core wires.
It has a structure in which the wide side surface of b is caulked in parallel with flat plates.

First, we will examine the deformation of the optical fiber when the tape core wire is crimped. FIG. 3 is a diagram illustrating the movement of the end face of the optical fiber due to the bending of the optical fiber when the tape core wire 2b shown in FIG. It is shown as follows. FIG. 3a is a diagram showing the movement of the optical fiber in the x direction and the y direction due to caulking compression, where x is the longitudinal direction of the optical fiber 1 and y is the width direction. The optical fiber 1 is bent between x=0 and L. Otherwise, it is a straight line.

FIG. 3c is a sectional view at x=L in FIG. 3a, where the broken line shows the initial state (before caulking and compression) of the tape cable core 2b, and the solid line shows the state after deformation by caulking and compression. Due to the crimping, the five optical fibers 1 move as indicated by broken line arrows in the figure. Figure 3b
3 is a sectional view taken along line BB' in FIG. 3a, showing movement of the optical fiber 1 in the thickness direction.

In FIG. 3, the amount of movement of the optical fiber end face in the x direction is defined. The broken line A-A' is the initial position of the tips of all the optical fibers 1, and the end face movement amount ΔL of each optical fiber is based on A-A'. Next, the movement of the optical fiber in the y direction is defined by Δp=p ₁ −p ₀ using the position of the central optical fiber as a reference. In addition, the thickness of the optical fiber is determined from the initial thickness t ₀ to
t ₁ , and the caulking compression deformation rate is (t ₀ − t ₁ )/t ₀
(=Δt/t ₀ ).

If the tip of the optical fiber 1 moves, the position of the end face of the connector plug and the end face of the optical fiber 1 will shift when the optical fiber 1 is attached to the connector plug and compressed and deformed, causing deterioration of connection loss. It is necessary to keep the amount of movement ΔL within a range that does not affect connection loss deterioration. Therefore, by defining the crimp compression deformation rate, the amount of movement ΔL of the optical fiber end face is determined.

In order to quantitatively evaluate the amount of movement ΔL of the optical fiber tip from the bending of optical fiber 1 in Figure 3, it is assumed that the volume before and after crimping compression deformation does not change, and the coating thickness changes from t ₀ to t ₁ . When, widthwise spacing p ₀
changes to p ₁ = (p ₀ ×t ₀ /t ₁ ). Therefore, when the optical fiber 1 is crimped. It moves by Δt/2 in the thickness direction, Δp in the width direction, and the end face position moves in the x direction. When the curved shape of optical fiber 1 is approximated by a cosine curve,
Its shape is expressed by equation (1), and the amount of movement of the end face of optical fiber 1 is determined from equation (2).

FIG. 4a shows experimental values and calculated values of the caulking compression deformation rate and the amount of optical fiber movement performed on the tape core shown in FIG. 7. In the diagram, the optical fiber No.
are numbered No. 1 to No. 5 in order of arrangement. From FIG. 4a, in order to suppress the amount of movement ΔL of the optical fiber surface within 50 μm, the crimping deformation compression ratio needs to be 35% or less.

FIG. 4b shows experimental values of the amount of movement of the optical fiber end face due to the crimp compression deformation rate and tension. For caulking lengths of 4mm, 8mm and 12mm, tape core wire
The experiment was conducted by applying a tension of 0.5 kg. As shown in Figure 4b, the optical fiber end face has a compression deformation rate of 15%.
Experiments have shown that it moves rapidly below. As a result of the above, the caulking compression deformation rate is 15% or more35
It turns out that it is necessary to keep it below %.

Next, consider the length of the caulking part. The optical fiber 1b may move due to the tension applied to the tape core during assembly and connection operations, and it is necessary to consider the caulking length in order to provide the necessary tension resistance.

FIG. 5 shows experimental values for the crimping length and optical fiber end face movement amount 11L when the crimping compression deformation rate was 25% and the tension was 0.4, 0.5, and 0.6 kg.
From Figure 5, in order to suppress the amount of movement of the optical fiber to 50μm at a tension of 0.5Kg, the crimping length must be 4
Must be at least mm.

As described above, by specifying the crimping compression deformation rate, the end face of the multi-core optical fiber can be positioned, and by specifying the crimping length, the tensile strength can be set to a practical strength. The allowable value for the gap between the end faces of the optical fibers is as follows: Satake, Nagasawa, Kashima, "Design and Characteristics of Plastic Molded Optical Fiber Multi-Fiber Connectors," Transactions of the Institute of Electronics and Communication Engineers '85/3, vol. J68, No. 3
Therefore, it was calculated from the connection loss due to the combination of axis misalignment and end face gap. In other words, the conditions for providing splice loss within 1 dB are assuming that the positional accuracy (i.e. axis misalignment) of the small diameter hole for optical fiber positioning is 4 μm, and the end face gap is 100 μm, so caulking compression is used to distribute the allowable value of the end face gap. A total of 50 μm due to deformation and 50 μm due to tension applied to the tape core wire.
It was set to 100 μm.

(Embodiment) Fig. 1 shows an embodiment of the connector plug of the present invention, in which Fig. 1a is a perspective view and Fig. 1b is a sectional view. 1 is an optical fiber, 2b is a tape core, 3 is a caulking plate having a flat shape, 4 is a transparent lid, 5 is a caulking screw, 6 is a male screw, and an adapter (not shown) (axis aligned by a guide pin) a tightening ring for connecting the optical fiber 1 with a sleeve-shaped adapter that can accommodate two connector plugs; A guide portion leading to the narrow positioning hole 7, 9 a hole for a guide pin, 10 a caulking stopper that determines the amount of caulking of the tape core wire 2b, 11 a tape core wire insertion opening at the rear end of the connector plug, 12
1 is a tape core wire insertion hole having a rectangular cross section, and 13 is a stopper for preventing the tightening ring 6 from falling. The length of the caulking plate 3 was 6 mm.

In the assembly of the multi-core optical fiber connector plug of this embodiment, after removing the covering of the tape core wire 2b, in order to obtain a high-quality end surface at the tip of the optical fiber 1, a plurality of optical fibers are assembled using a stress breaking method. Align the edges and cut. Next, the tape core wire 2b is inserted through the tape core wire insertion opening 11. This operation is easy because the insertion opening is tapered.

The tape core wire passes through the tape core wire insertion hole 12,
Reach the tip. At the tip, multiple optical fibers 1 can be confirmed through the transparent lid 4;
is guided from the guide portion 8 and inserted into the small diameter hole 7 for positioning the optical fiber. Next, align the optical fiber 1 on the same plane as the end surface of the connector plug, and tighten the caulking screw 5.
is tightened to caulk the covering of the tape core wire 2b and fix the optical fiber 1. At this time, caulking stopper 10
Since the crimping compression deformation rate is set to be 25%, the specified rate of change can be obtained simply by tightening the crimping screw 5.

In order to align the optical fiber 1 and the end surface of the connector plug on the same plane, a method was used in which the optical fiber was butted against the end surface of the connector plug with an acrylic plate or the like in close contact with the end surface.

The above assembly time was within 2 minutes, and the workability was good. Further, since the transparent lid has a convex top surface, it has a lens effect, the guide portion is enlarged, and the plurality of optical fibers 1 can be easily confirmed.

The amount of movement of the optical fiber end face in this example is approximately 30 μm when the crimping compression deformation rate is 25%, and 50 μm when a tension of 0.5 kg is applied, which can be estimated to be a total of 80 μm, and the splice loss is suppressed to within 1 dB.

FIG. 2 shows connection loss values of the connector plug of this example. The optical fiber used had a core diameter of approximately 50 μm,
It is a GI type with a cladding diameter of approximately 125 μm. The measurement conditions were steady mode excitation and a refractive index matching agent was used on the end face of the connector plug. The average connection loss is
It was 0.28 dB, and the maximum was 0.65 dB, which was within a range that did not pose any practical problems. Furthermore, it was found that the change in loss due to tension, etc. during operation was on the same level as that of conventional connectors, and that there was no problem due to change in loss during normal connector operation.

(Effects of the Invention) As described above, the multi-core optical fiber connector plug of the present invention has the advantage that it can be assembled in a short time because no adhesive is used. Furthermore, the connection loss has been achieved at a value that does not pose any practical problems.

Furthermore, the insertion port for inserting the optical fibers is large and easy to insert, and the transparent lid provided above the guide part of the small diameter hole for optical fiber positioning allows the alignment of multiple optical fibers to be confirmed, improving work efficiency. It has the advantage of being good. Another advantage is that the multi-core optical fiber connector plug can be reused by loosening the caulking screw.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the multi-core optical fiber connector plug of the present invention, and FIG. 2 is a diagram showing the distribution of connection loss values of the multi-core optical fiber connector plug of the present embodiment. Figure 3 shows the amount of movement of the end face of the optical fiber when the tape core wire is compressed and deformed by crimping, and Figure 4a shows the experimental and calculated values of the crimping compression deformation rate and the amount of optical fiber movement. Figure 4b is a diagram showing experimental values of the amount of movement of the optical fiber end face due to crimping compression deformation rate and tension, and Figure 5 is
Figure 6 shows the experimental values of caulking and optical fiber end face movement when tension is used as a parameter. Figure 6 shows the structure of a single fiber. Figure 7 shows the structure of a tape core. , FIG. 8 is a perspective view showing the structure of the core component of a conventional multi-core optical connector, and FIG.
FIG. 2 is a side view showing the structure of a conventional single-core optical connector. 1...Optical fiber, 2a...Single core wire, 2b...
Tape core wire, 3... crimping plate, 4... transparent lid, 5... crimping screw, 6... tightening ring, 7...
Small diameter hole for optical fiber positioning, 8... Guide portion, 9... Hole for guide pin, 10... Stopper for caulking, 11... Tape cable insertion opening, 12... Tape cable insertion hole, 13... Fall prevention stopper for tightening ring, 101... core ferrule, 102... core lid, 103... small diameter hole for optical fiber positioning,
104...Guide pin hole, 105...Glue injection hole, 201...Small diameter hole for optical fiber positioning,
202...core, 203...coupling nut, 204...spring, 205...house tube, 206...caulking mechanism, 207...clan sleeve, 207a...caulking part, 207b...outer periphery male thread part, 208 ... Clamp Nut, 208
a...Inner circumference female thread, 209...pipe.

Claims (1)

[Claims for Utility Model Registration] 1. A multi-fiber core in which the coating of the tip of a tape fiber in which optical fibers are assembled into a plurality of cores is removed, the end faces of the optical fibers are aligned, and a tape core wire is attached in which the end faces are formed by stress rupture. In the optical fiber connector plug, the end face of the connector plug includes a thin optical fiber positioning hole in which a plurality of thin holes having a diameter slightly larger than the outer diameter of the optical fiber are arranged in parallel, and two guide pins. and a tape fiber insertion port having a rectangular cross section that connects the tape fiber insertion port and the optical fiber positioning small diameter hole at the rear end of the connector plug. a hole; a guide portion for guiding each optical fiber to the optical fiber positioning thin hole at a connecting portion between the tape core insertion hole and the optical fiber positioning thin hole; and a guide portion on the guide portion. a transparent lid that allows the guide portion to be observed; a caulking plate for holding the tape core installed in a part of the way of the tape fiber insertion hole; a caulking screw for pressing the caulking plate; and an optical fiber. A connector plug for a multi-core optical fiber, characterized in that it has a caulking stopper that stops the caulking plate in order to define the caulking compression deformation rate of the conductor. 2. The utility model as set forth in paragraph 1 of the claims for registration of a utility model, characterized in that the caulking stopper is set so that the caulking compression deformation rate is 15% to 35%, and the length of the caulking plate is 4 mm or more. Connector plug for Shinko fiber core.