JPS5921365Y2 - fiber optic connector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical fiber connector used for connecting optical fiber transmission lines.

There are many conditions required for optical fiber connectors, but
Among these, especially important conditions are ■low loss, ■workability, ■reciprocity, and ■economic efficiency.

Conventionally, optical fiber connectors that have been put into practical use with these considerations in mind include a pair of plugs into which optical fibers are inserted and fixed (the outer peripheral surface of which serves as a reference for aligning the optical fiber axes).

) and a hollow cylindrical sleeve (socket) that guides the plug.

By aligning the optical fiber with the axis of a plug of specified size and fixing it, the plugs can be connected by simply inserting the plugs from both ends of the socket and butting them together.

Of course, the mating clearance between the plug and socket is several microns.
It is necessary to hold it within m.

The above-mentioned plug has been manufactured using plastic molding technology with good mass productivity and low cost (see, for example, Japanese Patent Laid-Open No. 52-60638).

FIG. 1a shows a cross section of the main part of the mold used for this molding, and the same figure shows a cross section of the molded plug.

In the figure, 1 is a mold, 2 is a pore for inserting an optical fiber, 3 is a part of a taper for guiding an optical fiber (cup-shaped depression), 4 is an optical fiber, and 5 is a fiber protection tube (jacket).
, 6 is a plastic molded plug, 7 is an abutting surface of the plug, and 8 is a conical protrusion (hereinafter referred to as a protrusion).

). Note that the end of the optical fiber 4 extending beyond this convex portion is cut off.

The convex portion 8 is a tapered portion 3 for guiding an optical fiber provided in the mold 1 to facilitate insertion of the optical fiber into the pore 2 of the mold.
This is caused by the presence of an inconvenient presence when inserting the plug from both ends of the socket and butting them together.The protrusion 8 must be removed by polishing (requires a long time) or the Assemble the outer circumferential surface of the plug 6 into a tapered shape (the cross section is trapezoidal), use a tapered sleeve (requiring precise control of the taper angle) for the socket, and leave a predetermined distance between the opposing abutting surfaces. It is necessary to create a structure that prevents the tips of the optical fibers from coming into direct contact with each other, or to take measures such as inserting or attaching a spacer to the mating surfaces. was.

However, it has been found that the convex portion 8 is very useful when cutting the end of the optical fiber 4 and creating an optical fiber end face at a predetermined position.

In other words, the advantages and disadvantages of cross-sectional processing of the optical fiber 4 at the plug end face (butting surface 7) without a convex portion as shown in FIG. It is.

Optical fibers are usually cut by using a diamond blade 9 to inflict damage on the circumference of the surface of the optical fiber, and then pulling it.

In this case, the depth and uniformity of the damage are important and will determine whether the cut end face of the optical fiber will have a mirror finish or not.

In the case of FIG.
The tip 10 of the plug rubs against the end face of the plug, making it difficult to control the wound pressure and making it difficult to obtain the desired depth of wound.

Therefore, if the optical fiber is damaged at a position away from the end face of the plug, it is difficult to position the blade edge and the damage line forms a line, making it difficult to obtain a good cut surface.

On the other hand, in the case shown in the figure, the above-mentioned problems are not present, and the optical fiber can be easily damaged and cut at the tip of the protrusion 8 (the apex of the protrusion).

Therefore, the purpose of the present invention is to
It is an object of the present invention to provide an optical fiber connector that overcomes the problems of the above, has a structure that takes advantage of its advantages, has low loss, and can be easily assembled and detached.

In order to achieve the above object, the mold itself must not only have high precision, but also the optical fiber must be easily inserted into the pores provided in the mold.

The mold of the present invention has a part of the taper for guiding the optical fiber in the same manner as before, and also has a groove for creating a ring-shaped abutment surface on the peripheral edge of the opposing surface of the plug, and the groove is inserted into the part of the taper at a depth. The structure is slightly deeper than that of the original.

The plug, which is integrally molded with the optical fiber using this mold, has a protrusion (protrusion) at the center of the opposing surface produced by the tapered part, and a ring formed by the groove and slightly higher than the protrusion. The convex portion is effectively used for cutting the optical fiber, and the abutting surface prevents the end surfaces of the optical fibers from coming into contact with each other when the pair of plugs are opposed in the socket, and maintains the desired spacing. Helps keep it.

The present invention will be explained in detail with reference to Examples below.

FIG. 3a is a sectional view of a main part of the plug molding die of the present invention, and the same figure is a sectional view of a molded plug.

In the figures, the same reference numerals indicate the same or equivalent parts.

As is clear from the figure, the mold of the present invention is provided with a ring-shaped groove 11 having a depth a that forms an abutting surface;
The value of is greater than the depth β of the tapered portion 3.

Therefore, in the plug molded using this mold, the convex part 8 holding the optical fiber 4 in the center is a (= α
−β) is formed at a retracted position.

The plastic material for plug molding is, for example, an epoxy resin, which is solidified by pressing at ~30 kg/cm2 and heating to about 150°C.

In this case, if the diameter of the optical fiber to be inserted is 150 μm, it is appropriate to select the diameter of the pore 2 in the mold to be about 153 μm, so that the optical fiber fits well and the above-mentioned molding from the gap is possible. The outflow of resin can also be kept to a very low level.

FIG. 4 is a diagram illustrating the cutting process of the optical fiber end in the molded plug of the present invention.

The tip 10 of the blade 9 is applied to the optical fiber at the apex of the convex portion 8, and the main body of the plug 6 is rotated and damaged.

At this time, the cutting edge 10 does not come into contact with the plug body, and the applied pressure can be easily controlled.

Although not shown, the incision pressure is normally controlled by varying the load on the tip 10 using an automatic control mechanism.

Further, the blade 9 may be rotated along the outer peripheral surface of the optical fiber 4 instead of rotating the plug body when damaging the optical fiber 4.

The positioning of the tip 10 is done using the ring-shaped abutment surface 7 and the apex of the convex portion 8 as guides, so it is very easy to position, and the workability is improved.

Moreover, since the optical fiber cutting position is reinforced by the convex portion 8, the cutting operation (damaging, pulling) can be performed stably.

Figures 5a and 5l) show modified examples of the shape of the convex portion 8,
As shown in the figure, the shape of the protrusion 8 is not limited to a conical protrusion, but may be trapezoidal or spherical as long as it does not affect the load on the blade edge and allows easy guidance when inserting the optical fiber. You can also.

FIG. 6 is an assembly diagram of the optical fiber connector of the present invention.

A pair of plugs whose optical fiber end faces 12 have been cut are fitted into a socket 13 and abutted at a ring-shaped abutting surface 7.

Assembling is simple as described above, and since the axes of the optical fibers of both plugs are aligned and a gap of 2a is ensured between the end faces, it is possible to avoid characteristic deterioration due to breakage of the optical fibers.

In addition, when examining the effect of the gap in 2a above, the core diameter was 50 to 100 μm, and the numerical aperture NA was 0.15 to 0.2.
It was found that in a silica-based optical fiber having a diameter of 0.0, the connection loss can be reduced to 1 bB or less if 2a is 50 μm or less.

In order to reduce Fresnel loss due to refractive index discontinuity at the tip of the optical fiber, the tip should be adjusted to the refractive index of the optical fiber (n: 1.
4 to 1.5) may be covered with a flexible material (for example, silicone resin).

When the connector plug is inserted and fitted into the socket, the flexible material (contact) is deformed, and the distance between the optical fiber tips is determined by the dimensions of the molded product, so stable characteristics can be expected.

As explained above, the optical fiber connector of the present invention is
It is easy to insert the optical fiber and cut the end of the optical fiber when manufacturing the plug, improving work efficiency.In addition, assembly and attachment using a socket are easy and can be done with high precision, reducing splice loss characteristics. You get what you get.

[Brief explanation of the drawing]

Figure 1a is a cross-sectional view of the main parts of a conventional plug manufacturing mold, the same is a cross-sectional view of a conventional plug, Figure 2 is an explanatory diagram of the cutting process of the end of an optical fiber, and a is a plug without a protrusion. The end face b indicates a plug end face with a convex portion. Fig. 3a is a cross-sectional view of the main part of the plug molding mold of the present invention, and a cross-sectional view of the molded plug; Fig. 4 is an explanatory diagram of cutting the optical fiber end of the plug of the present invention; Figures a and b are modified examples of the convex shape of the plug end face, and Figure 6 is an assembled view of the optical fiber connector of the present invention. 1... Mold, 2... Pore for inserting optical fiber, 3... Part of taper for guiding optical fiber, 4
...Optical fiber, 6...Plug, 7.
...Abutting surface, 8...Protrusion, 9...
...Blade, 10...Blade, 11...
・Ring-shaped groove, 12... Optical fiber end surface, 13
······socket.

Claims (1)

[Scope of utility model registration request] An optical fiber comprising: a pair of plugs into which optical fibers are inserted and fixed; and a hollow cylindrical socket that aligns the axes of the pair of plugs and interconnects the transmission lines of the optical fibers. In the connector, each of the plugs has a ring-shaped abutting surface on the peripheral edge of the opposing surface, and a convex portion for positioning the end face of the optical fiber is provided at the center of the opposing surface. The tip of the convex portion positions the cutting edge for cutting the optical fiber held by the convex portion at the tip of the convex portion, and the end face of the optical fiber cut at the tip of the convex portion. An optical fiber connector characterized in that the connector is formed so as to be held in a position retracted from the abutting surface.