JPS597914A - Optical connector - Google Patents

Abstract

PURPOSE:To reduce optical coupling loss and cost and to facilitate fitting to an optical fiber by forming a recessed part for an adhesive overflow at the pivotally supporting part of the opposing end surfaces of a ferrule and preventing adhesive from sticking to the end surface of an optical fiber element wire. CONSTITUTION:The recessed groove 15 is formed in the end surface of the ferrule 3. The end surface 2' of the optical fiber element wire 2 crosses the axial center and a specular surface. When the fiber 1 is inserted into the axial hole of the ferrule 3, its end surface is 10-50mum deeper than the end surface 6. Their outer circumferential surfaces are coated with adhesive (exposy resin) 7 which has good transparency and a refractive index close to that of the core and both are fixed together. A part of the adhesive in pores 5 is forced out toward the side of the end surface 6 by the end surface 2' through the sliding motion of the element wire 2 to stick to the end 2' partially, but the majority of them sticks to the bottom surface of the recessed groove 15 and solidified. Further, an elastic solid filter 16 such as epoxy resin is provided to the recessed groove 15 at the circumferential edge. Therefore, the end surface 2' never strikes the opposing end surface 2'.

Description

[Detailed description of the invention] (a) Technical field of the invention The present invention relates to an optical connector.

Φ) Technology Background With the advancement of optical fiber transmission technology, low-loss, low-cost optical connectors are required.

(C) Conventional technology and problems An example of an optical connector is shown in the cross-sectional view of FIG.

In the figure, 3 is a substantially cylindrical ferrule made of metal such as stainless steel, and has a shaft hole 4 provided at the shaft center and a small hole 5 penetrating the end surface 6 at the tip of the shaft hole 4. The end of the optical fiber 1 and the exposed optical fiber strand 2 are respectively inserted and fixed with adhesive (for example, epoxy resin). 8 is an adapter made of gold (e.g. stainless steel), and a ferrule 3 is attached to the shaft center.
A hole 9 is provided into which the tip of the plug is inserted without a gap, and screw threads into which plugs 11, which will be described later, are screwed are formed on the outer peripheral surfaces of both sides. Further, at both ends of the hole 9, a circular recess 10 is provided which coincides with the axis into which a part of the flange 31 provided in the middle of the ferrule 3 is inserted.

The tips of ferrules 3 having the same shape are inserted into the holes 9 of the adapter 8 from both ends, and the respective end surfaces 6 are in close contact with each other at the center of the holes 9. The bag-shaped plug 11 is inserted into the outer periphery of the opposite end of the ferrule 3 of each optical fiber 1, and the screw hole is screwed into the thread of the adapter 8, so that the flange 3 The end faces of the ferrules 3 and 3 are pressed toward the adapter 8 side, and the end faces of the respective ferrules 3, that is, the end faces of the optical fiber strands 2, are held in close contact so that they do not come apart.

With this configuration, the two optical fiber strands 2 are brought into contact with each other without any misalignment of their axes or angles, and are optically coupled with little coupling loss.

It should be noted that the ferrule 3 and the optical fiber 1 are completely fixed, and in particular, they are bonded with an adhesive 7 so that the optical fiber cable 2 does not move in the radial and axial directions within the pore 5. is important. For this purpose, the adhesive 7 is sufficiently applied to the outer surface of the optical fiber 2, or the axial hole 4 of the ferrule 3 is filled with the adhesive 7, and the optical fiber 1 is inserted into the ferrule 3 and repeated in the axial direction. Then, the adhesive 7 is applied uniformly to the inner circumferential surface of the pore 5 to bond it.

Conventionally, two methods shown in FIGS. 2 and 3 are known as methods for precisely finishing the end face of the optical fiber strand 2.

FIG. 2 is a front view when a lapping machine is used. The end face 6 of the ferrule 3 to which the optical fiber 2 is bonded is brought into contact with the upper surface of the wrap surface plate 13 that rotates about a vertical axis, and the end face of the optical fiber 2 and the end face of the 7 ferrule 3 are brought into contact with each other. At the same time, wrap and make it special.

(a) in FIG. 3 is a front view of cutting the optical fiber 2;
←) is a cross-sectional view showing the optical fiber 1 inserted into the 7-erule 3 after the step (a). In Figure 3,
14 is a cutter blade made of diamond or ceramic attached to a known manual fiber cutter (not shown). When such a fiber cutter is used, the optical fiber 2 can be cut into four end faces with desired dimensions. Thereafter, the end portion of the optical fiber 1 is inserted into the 7-erule 3 and fixed with an adhesive.

However, the former method shown in FIG. 2 requires a large number of man-hours, is not suitable for weighing, and requires a lapping machine, which is expensive. Particularly, in order to attach connectors at an optical fiber installation site, a lapping machine must be used each time, which is a cumbersome method.

In the latter method shown in FIG.
This hard coating covers the end face of the ferrule 37il-
When inserted into the adapter 8, it collides with the end face of the opposing optical fiber strand, causing it to break, making the surface of the coating or the end face of the optical fiber 2 uneven, increasing the amount of light reflected, and coupling. loss? Furthermore, even if the end face is not destroyed, stress is added to the fiber and its periphery, making reliability unfavorable.

(d) Object of the Invention An object of the present invention is to provide an optical connector in which the above-mentioned conventional problems are eliminated.

(e) Structure of the Invention In order to achieve this object, the present invention forms four parts in which an adhesive overflows at the pivoting portions of the opposing end faces of the zeta ferrule, and the adhesive flows onto the end face of the optical fiber. This is to prevent it from being blasphemed, and to prevent it from hitting the opposing b to the opposing b, even if it is held in place. Further, the concave portions are filled with a solid matching agent 1f,j so that the matching agents come into close contact with each other so that almost no light is reflected.

(Embodiments of the Invention The present invention will now be described in detail with reference to the illustrated embodiments. Note that throughout the drawings, the same object is indicated by a voice symbol.

FIG. 4 shows the main parts of an embodiment of the present invention, in which (a) is a plan view, (b) is a front sectional view, (-c is a detailed view of the dotted heald frame M portion, and two). FIG. 3 is a partial cross-sectional view showing the ferrule inserted into the adapter.

In FIG. 4, a concave groove 15 is formed in the end surface 6 of the ferrule 3, which is perpendicular to the axis and has a width that is larger than the diameter of the optical fiber 2 and a desired depth. The optical fiber wire 2 is cut by the above-mentioned optical fiber cutter so that the end surface 2' is almost perpendicular to the axis and has a mirror surface. When the optical fiber is inserted into the shaft hole of the ferrule 3, the end face 2' of the optical fiber 2 is still connected to the end face 6 of the ferrule 3.
Cut to a predetermined length at a position that is 1 to 50 μm (the less the better for this dish).

An adhesive (for example, epoxy resin) 7 having good transparency and a refractive index close to the refractive index of the core of the optical fiber is uniformly applied to the outer circumferential surface of such optical fiber 1 and optical fiber strand 2.
Insert it into the ferrule 3 and fix it. In this case, a portion of the adhesive 7 filling the pores 5 is pushed out toward the end surface 6 by the end surface 2' of the optical fiber 2 by sliding and reciprocating the optical fiber 2. A part of the extruded adhesive 7 adheres to the surface of the end 2', but most of it flows around the optical fiber strand 2, adheres to the bottom of the groove 15, and solidifies.

Even if the 7-errule 3 is inserted into the adapter in this flat I state, the end face 2' will not collide with the end face 2' of the opposing optical fiber (because the end faces 6 are in close contact with each other), so the optical coupling loss will be reduced. Although it is small, this embodiment further eliminates the presence of an air layer between the end faces 2' and further reduces the amount of light reflected.

That is, a concave groove 15 on the periphery of the end face 2' is filled with a matching agent 16 (for example, a solid matching agent such as epoxy resin or silicone) 16 to match the core refractive index of the optical fiber 2. Since this matching agent 16 has an elastic solid shape, when two 7-erules 3 are faced and their end surfaces 6 are brought into close contact with each other as shown in FIG. 4, the matching agent 16 protruding from the end surface 6 ,
They are pressed together and elastically deformed so that they are parallel to the end surface 6 and come into close contact. Therefore, not only is there no air layer between the end faces 2' of the two opposing optical fiber strands 2, but also the difference in optical properties caused by the adhesion state of the adhesive 7 on the end faces 2' can be reduced. It is possible to reduce the connection loss.

Furthermore, since the optical fiber wire 2 is cut with a small, manually operated seven-eye cutter, the equipment cost is low, the work is easy, and the optical connector is low cost.

The present invention is not limited to the illustrated embodiment, but may be modified as appropriate within the scope of the claims, for example, instead of a groove, a circular recess is provided around the circumference.

(Armor) As described in detail, the present invention has extremely excellent practical effects such as low optical coupling loss, low cost, and ease of installation at the end of an optical fiber. It is an optical connector.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of an example of an optical connector, Figure 2 is a front view showing a conventional processing method for the end face of an optical fiber, and Figure 3 is a front view showing another conventional processing method. Fig. 4 shows an embodiment of the present invention, and 0) (→, (c), and 2) are plan views of key points, respectively. and a cross-sectional view. In the figure, 1 is an optical fiber, 2 is an optical fiber wire, 3 is a ferrule, 4 is an axial hole, 5 is a pore, 6 is an end face of the ferrule, and 7
1 is an adhesive, 8 is an adapter, 11 is a plug, 13 is a lap surface plate, 14 is a canter blade, 15 is a groove, and 16 is a matching agent. Agent Patent Attorney Hiroshi Kasen - Kasen City 1M Figure 4

Claims (1)

[Claims] (1) In an optical connector in which the end portion of an optical fiber is inserted into a hole drilled in the axis, and ferrules fixed with adhesive are mounted facing each other, the fine details of the opposing end surfaces of each ferrule are 2. The optical connector according to claim 1, wherein a concave portion is formed in a portion thereof to allow the adhesive to overflow.