JPS58195814A - Optical connector and its production - Google Patents

Abstract

PURPOSE:To assemble an optical connector easily with high accuracy by using a plug formed with a hole for insertion of an optical fiber by a core pin projecting from the end face of a core forming the end face on the butt side of the plug in the stage of forming the plug. CONSTITUTION:A core pin 37 which forms a hole 8 for insertion of the strand 2 of an optical fiber 1 is erected on a core 34 forming the forward end face of a plug 6 in the stage of forming the plug 6; thereafter, said plug is formed, whereby the hole 8 is formed with high accuracy in the position matching to the plug 6. The covering at the end face of the fiber 1 is removed and a cap nut 15 and a spring 19 are inserted onto the fiber, then the fiber 1 is inserted into the holes 7, 8 of the plug 6 injected therein with an adhesive agent until the strand 2 projects from the forward end of the plug 6. The adhesive agent is allowed to set to fix the plug 6 and the fiber 1 to one body, whereafter the strand 2 projecting from the forward end face of the plug 6 is cut and the end face of the plug 6 is polished to a specular surface.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical connector for connecting an optical 7-eyeper used in an optical communication system, and a method for manufacturing the same.

As the next generation of electrical information transmission system,
Optical information transmission systems, or optical communication systems, have been developed.

In this optical communication system, an optical signal oscillated on the transmitting side is sent to the receiving side via an optical fiber formed with a thickness of 100 to several 100 nm, and the receiving side converts the optical signal into an electrical signal and takes it out. In such optical communication systems, an important issue is how to efficiently and stably transmit signals from the transmitting side to the receiving side.

In an optical communication system, optical loss occurs at the joint (butt) between an optical fiber that transmits a signal and an optical connector that connects the optical fiber.

And the loss in the optical fiber is α several dB/km ~
Progress is being made to reduce the loss to about 1 dB/1 dB/.

On the other hand, in an optical connector, the amount of loss greatly depends on the eccentricity of the axes of a pair of optical fibers that are butted together by the optical connector. For example, cladding diameter 1
25 μm In the case of an optical fiber with a core diameter of 50 μm, if the axes of the butted optical fibers are about 4 μm eccentric, Q, 5
dB, and if the eccentricity is about 7 μm, a connection loss of 1 dB will occur.

Therefore, in order to carry out long-distance communication, repeaters are installed at required intervals, and attenuated signals are amplified and transmitted each time. At this time, if the connection loss in the optical connector increases, the number of repeaters must be increased. Increasing the number of repeaters is not only economically undesirable, but also causes many problems, such as complicating maintenance and inspection and reducing the reliability of the entire communication system.

In addition, since the required length of each optical fiber differs depending on its installation location and route, the work to attach the connector to the Hikari 7 Aipah terminal should be easily done on-site. That is required.

Therefore, optical connectors are required to have low connection loss and be easy to assemble.

Optical connectors usually have seven flanges formed in the middle of the outer circumferential surface, a plug with a hole in the axial center to accommodate the optical fiber, and a through hole in the axial center that fits into the outer circumferential surface of the plug. The plug includes a sleeve with a thread formed on its outer circumferential surface, a cap nut that is screwed into the thread of the sleeve, and a spring that is inserted between the plug bottle and the cap nut to maintain a constant abutting force of the plug. . The positional accuracy of the optical fiber is determined mainly by the accuracy of the plug and sleeve, and a particularly important task is to reduce the deviation between the axes of the plug and the optical 7-eyeper.

For this reason, conventionally, the outer shape of the plug was formed from hard metal.
Generally used are those with two double eccentric tubes built into the shaft center, and those with a jewel or ceramic guide embedded in the shaft center and a hole slightly larger in diameter than the optical fiber formed in the guide. .

However, in the case of a plug using a double eccentric cylinder, after fixing the light 7A to the center eccentric cylinder, the two eccentric cylinders are moved while observing with a microscope, and the axis of the original fiber-pan plug is adjusted. In addition, in plugs with embedded guides, the tip of the optical fiber is positioned by the guide, which greatly improves workability on site. It has the advantage of However, machining the plug, that is, drilling a hole with α number n in the guide, requires a high degree of skill and a long machining time, which has the disadvantage of extremely poor productivity.

Hereinafter, the purpose of the present invention is to carry out the invention as described above. An object of the present invention is to provide an optical connector that eliminates the drawbacks of the prior art and allows easy and highly accurate assembly at a site where optical fiber connections are required, and a method for manufacturing the same.

In order to achieve the above object, in the present invention, the sleeve and plug constituting the original connector are made of the same kind of synthetic resin, and when forming the plug, the insertion hole of the optical 7 eyeper of the plug is It is characterized in that it is formed by a core bin protruding from the end face of the core formed on the side end face.

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

FIG. 1 shows a state in which optical fibers are connected using the original connector according to the present invention. The optical fiber 1 is coated with a primary coat 3 and a secondary coat 4 for reinforcing the element @2 and the cumulative Iw2 for transmitting light.The plug 6 of the optical connector 5 includes: A hole 7 into which the optical fiber 1 from which the secondary coat 4 has been removed is inserted, and a hole 8 into which the strand 2 is inserted, are formed in a cylindrical shape so that they communicate with each other. lunge 9
is formed. A through hole 11 into which the plug bottle 6 is inserted is formed in the sleeve 10.
A tapered guide portion 12 that expands toward the opening is formed at both ends. Also, Su! J-7' 10 has a central 7 flange 13 on its outer peripheral surface, and screws 14 on both ends.
are formed respectively. The cap nut 15 is formed into a cylindrical shape in which the plug bin 6 is slidably fitted, and a through hole 17 is formed in which the seventh flange 16 facing the seventh flange 9 projects. is the sleeve 1
A thread 18 is formed which threadably engages with the thread 14 of No. 0.

The spring 19 is inserted into the outer periphery of the plug 6 so as to be located between the seventh flange 9 and the seventh flange 16.

Note that between the plug 6 and the secondary coat 4 of the optical fiber 1,
The clamp ring 20 and the cable cap 21 are integrally connected, and when the plug 6 is inserted into or removed from the sleeve 10, no insertion/extraction force is applied to the element II2.In the above structure, the optical connector is assembled by: It is done as follows.

The optical fiber 1, the plug 6, the sleeve 10, the cap nut 15. The spring 19, the clamp ring 20, and the cable cap 21 are each formed into a required shape at a factory, and transported individually to the site. At the site, first attach the cable cap 21, clamp ring 201, and cap nut 15 to the terminal of the optical fiber 1 to be connected. Insert the spring 19 in this order and move it to a position where it will not interfere with your work. Next, the secondary coat 4 was removed to a predetermined length from the end of the Hikari 7 Eyepa 1, and the primary coat 3 was removed to a predetermined length from the end.
1. Clean the area from which the coating was removed with 1 organic solvent. Meanwhile, the hole 7.8 of the plug bottle 6 is filled with an appropriate amount of adhesive. Then, the end of the optical fiber 1 is inserted from the 67 side of the plug bin, and pushed in until the strand 2 protrudes from the hole 8 by a predetermined amount. After the adhesive has hardened, the tip χ of the plug 6 is fixed, and the compressible range of the cap nut 1st spring 19 is used to move and lock the tip of the plug 6, and then the clamp ring 20'4 Position the optical fiber 1 so that one end covers the lug 6 and the other end covers the secondary coat 4 of the optical fiber 1, and glue the clamp ring 20, plug 6, and secondary coat 4 with adhesive. Glue the pull cap 21 to the clamp ring 20 and secondary coat 4. Then, release the cap nut 15v and return it to the center of the optical fiber 1 with the spring 19. Then, plug the plug 6
Cut the wire protruding from the tip of the plug to match the tip of the plug 6. Next, the plug 6 is inserted into a lapping jig and the tip of the plug 6 is polished. After polishing to the required surface roughness, the bare surface of the lug 6 is cleaned. Then, when the plug 6 is inserted into the sleeve 10 and the cap nut 15 is tightened, the connection of the optical fiber 1 by the optical connector 5 is completed. Note that the space between the hole 7 of the plug 6, the element 412, and the secondary coat 3, and the space between the element 68 and element II2 are filled with adhesive. 15 is molded by a conventional molding method.

The plug 6 is molded using a mold whose main part is only shown in FIG. Note that the parts not shown are the same as those of the known three-piece structure mold.0 In FIG.
1 is provided protrudingly. A plug 6 is attached to the template 32 on the fixed side.
35 first cores forming the outer periphery of the tip are buried. A second core 54 forming the tip end surface of one lug 6 is embedded in one end of this core 53. This core 54
A hole 35 for removing air from the cavity forming the plug 6 and a hole 36 that communicates with the hole 55 and accommodates the air inside the cavity together with the resin are formed in the hole 35 . A second cavity is formed by the fixed side mounting plate 50 and the hole 56. At the center of the end face of the core 34,
A core bin 57 that is considerably thicker than the strand 2 of the optical fiber 1 is provided upright. A core 39 forming the outer periphery of the seven flanges 9 and the rear end of the plug 6 is embedded in the movable side template 3B. A disc-shaped groove 40 is formed in the movable template 38 and the core 39, forming a disc-shaped launch with the template 52, and an annular protrusion 4 formed in the core 59.
An annular gate is formed between the plate 1 and the plate 32. The ejector pin 42 is slidably inserted into the core 59 and forms the rear end surface of the plug 6. Furthermore, a core bin 45 on the movable side, which is thicker than the outer diameter of the secondary coat 4 of the optical fiber '1, is slidably inserted into the axis of the ejector bin 42, and when the mold is clamped, the tip of the core bin 4S is It comes into contact with the core bin 57.

With such a configuration, when the mold is clamped and the synthetic resin 44 is supplied from a molding machine (not shown) to the runner, the synthetic resin 44 fills the runner and passes through the gate to the core 55154, the core bin 37°, the core 39. At this time, it flows into the cavity formed by the ejector bin 42 and the core bin 4S, and the plug bin 6 is formed.
Air in the cavity that has not been exhausted from the mating surfaces of the source or other gaps is forced into the second cavity through the hole 35. When the mold is opened after the synthetic resin has hardened, the movable mold plate is first retracted. Then, the molded plug 6 moves together with the movable template 58. At this time, the synthetic resin stuck in the hole 35 is broken, and the plug 6 and the synthetic resin in the second cavity are cut off. When the movable mold plate 38 is sufficiently retracted, the ejector bin 42 is actuated to protrude one lug 6χ from the core 59 and further from the core bin. At the same time, the stationary template 52 moves together with the movable template 58 and separates from the fixed mounting plate 30. Then, the hardened synthetic resin flowing into the second cavity is caught in the ejector bin 31 and remains on the fixed side mounting plate 30, so that the hardened synthetic resin inside the holes 55 and 56 of the core 54 is removed. In this state, the hardened synthetic resin is removed from the ejector bin 31.

Like this, the tip of plug 6? By erecting a core bin forming the 68 for inserting the strands of the optical fiber 1 into the core to be formed and forming the plug 6, the position of the 68 with respect to the plug 6 can be formed with extremely high precision. be able to.

Further, by providing the second cavity, the shape accuracy of the tip of the plug 6 can be improved.

The plug 6 is molded using a thermosetting resin or a thermoplastic resin, but since the synthetic resin alone has extremely low hardness compared to the base material s2 of the optical fiber 1, the end face of the 1 lug 6 after the optical fiber is assembled is During polishing, the amount of protrusion of the strands 2 protruding from the end face of the one lug 6 increases. For this reason, the hardness of the plug 6 is improved by mixing inorganic fibers with the synthetic resin. As the fiber, for example, glass beads, hollow glass bulbs, volcanic glasses, metals such as aluminum and iron and their oxides, graphite, calcium carbonate, etc. can be used.

Using synthetic resin as the example, gelicarbonate, which is generally easy to handle,
As fiber, glass fiber, carbon fiber, average particle size 1
Using a glass piece of 0Irn, a plug 6 was formed using the mold shown in Fig. 2, and the dimensions and connection characteristics shown in Figs. 3 and 4 were measured, and the pass/fail judgment was made.0 Measurement items is as follows.

(1) Roundness of the tip of the plug 6, (2) Plug 6
Concentricity (offset position) of the axis of the 68 with respect to the axis of the tip of the plug (3) Length I from the flange 9 of the plug 607 to the tip
(4) Surface roughness of the outer circumferential surface of the plug 6, (5) The tip surface of the plug 6 after assembly and polishing, and the tip of the element 112. (6) Connection loss as optical connector 5.

In addition, the criteria were that the connection loss was 1 dB or less, and the height difference between the plug and the top was 4 or less.

The results are shown in Figure 1. (Nao, in the table)
The connection loss was measured with the fitting clearance between the plug bin 6 and the IJ-sphere 10 set to 0. The same applies to Tables 2 to 4) As is clear from Table 1 above, glass beads Y 95-5o, 2 wt% was added to polybonate as a filler.
Additives are suitable for optical connectors. Note that, in addition to glass beads, a hollow glass bulb, quartz glass, or the like may be used as the fissure.

If more than 30 glass beads are added, the mechanical properties of the plug bottle 6 will deteriorate or it will become impossible to form it.

Further, it is necessary to uniformly disperse the glass beads in the polycarbonate, and the amount of glass beads added in actual production is preferably 10 to 30 times.

On the other hand, when used as the optical connector 5, the sleeve 10
On the other hand, the plug 6k is inserted and removed repeatedly. therefore,
In locations where insertion and removal are frequent, it is desirable to reduce the wear Y between the plug 6 and the sleeve 10. Therefore, among various lubricants, tetrafluoroethylene (PTFE) and molybdenum disulfide (Mo8.) Y were added to measure the lubricating effect.

The measurement items were the same as those in Table 1 above, with the addition of connection loss after 200 insertions and removals.

Furthermore, the criterion was that the connection loss after 200 insertions and removals should not be greater than α2 dB compared to the initial connection loss.

Note that polycarbonate F to which 50 wt% of glass beads were added was used.

The results are shown in Table 2.

Table 2 As is clear from Table 2 above, when using a p'rpgv lubricant, the expected lubricating effect cannot be obtained unless it is added at least 5 wt%. If it exceeds it, the fluidity during molding will decrease, which is not preferable. Therefore, when adding PTFB, 5 to 5
Qwt% should be C. Also, in the case of Mob,
1-5% force is optimal.

Example 2゜Synthetic resin, epoxy resin, fiber, average particle size 10/! The same study as in Example t was carried out using fO glass beads made of quartz glass.The results are shown in Table 3.

-Margin below- Table S ”“ [ [ Note: The table shows the case of epoxy resin only.

As is clear from Table 3 above, when molding 1 TEGU 6 using epoxy resin, it is desirable to add 30 to 80 wt% of glass beads Y as fissure to the epoxy resin. When the glass bead force exceeds Xst%, the fluidity of the resin during molding decreases, resulting in a decrease in moldability.

Here, in the case of epoxy resin, Fisi's slJ.

The outer diameter of the sleeve 100, the inner diameter d1 of the hole 8 of the lug 6, the outer diameter of the tip of the plug 6, and the inner diameter of the through hole 11 of the sleeve 100 must be regulated. 2, to make one mosquito against the axis of hole 8 of plug 6,
The inner diameter d1 of the hole 8 is 4! It is sufficient if it is the same as the outer diameter D1 of i2. However, the inner diameter d of 68 and the outer diameter D of element 4112
If 1 are the same, it will not only be difficult to pass the base @2 through the hole 8, but also there will be no gap between the hole 8 and the base 4I2 for the adhesive to enter. On the other hand, the diameter d1 of 68 is the outer diameter D1 of element @2
If it is sufficiently larger, the amount of eccentricity between the fine center of 68 and the axis of element 412 becomes large. Therefore, the inner diameter dl of the hole 8 is the element I!
Make the outer diameter 1 to 2 μm larger than that of No. 2. Then hole 8
It is easy to insert two strands of wire into the strand, and the eccentricity between the 68 and the strand 412 can be kept to 11.5 to 1. Also, 68 and elementary I! Adhesive flows into the space between 20 and bonded.

Further, the outer diameter of the plug 6 and the inner diameter d of the sleeve 10J are determined by the insertion/extraction force of the plug 6 and the connection loss. For example, the outer diameter of the plug 6 and the sleeve 10
Assuming the difference between the inner diameters d (D, -d*>w), the insertion/extraction force and connection loss of the plug 6 with respect to the sleeve 10 are as shown in Fig. 6. Fig. 6 shows the epoxy resin with 69% filler. 'lk: Added plug 6 to sleeve 100
In Figure 6, "P" represents the insertion/extraction force, and "B" represents the connection loss. When the fitting clearance is in the region (c), the plug 6 is press-fitted into the sleeve 10, and although the insertion/extraction force is large, the connection loss is small.

On the other hand, it can be seen that in the area where the fitting clearance is (g), the insertion/extraction force is small, but the connection loss is large.

Further, FIG. 7 shows the relationship between the number of insertions and removals and the amount of change in connection loss with respect to initial connection loss. In FIG. 7, a indicates Y when the initial fitting clearance is 13 μm, and b indicates Y when the initial fitting clearance is 12 μm. As is clear from Fig. 7, as the fitting clearance increases in the (→ region),
The frictional force between the plug 6 and the sleeve during insertion and removal also increases, and wear increases accordingly, resulting in a large change in connection loss.

However, if the fitting clearance between the plug 6 and the sleeve 10 is set in the range of −5 to +2 μm, it becomes possible to suppress the connection loss caused by insertion and removal of the plug 6 to 1 dB or less.

FIG. 8 shows the effects of the combination of materials of the plug 6 and sleeve 10 and temperature changes on connection loss.

In Fig. 8, A1 indicates that the sleeve 10 is made of epoxy resin and the plug 6 is made of polycarbonate, and B1 indicates that both the plug 6 and the sleeve 10 are made of epoxy resin (the fitting clearance is 22°). (C is set to 0.) As is clear from FIG. 8, if the same material is used, it will not be affected by the concentration. Therefore, it is desirable that the plug 6 and sleeve 10 be made of the same material.

As the adhesive, an epoxy adhesive with low viscosity (viscosity of 20 voids or less) is used. Also, if fisi is added to the adhesive, the amount of eccentricity between the axis of the hole 8 of the plug 6 and the strand 2 of the optical fiber 1? Can be made smaller. For example, the fisi added to the adhesive is d,=D,
When the adhesive has a diameter of 11 μm, 40 to 60 wt% of alumina powder having an average particle size of 0.3 μm is added to the adhesive. Then,
Since the fisi are uniformly distributed between the hole 8 and the element @2,
The amount of eccentricity between the axes of the hole 8 and the element 412 can be set to α2 μm or less at maximum. Incidentally, the average particle size of the Firano particle size is approximately 50 to 70% of the clearance between 68 and 41!2.

The material of the fish is also selected appropriately.

FIG. 9 shows another embodiment of the present invention, in which the same parts as in FIG. 1 are designated by the same reference numerals. The glass pipe 25 is inserted into the element @2 of the optical fiber 1, inserted into the hole 7 of the plug 6 together with the element 4I2, and connected to the lug 6 and the element wire 2 with adhesive.

With this configuration, it is possible to monitor areas with large temperature changes, such as monitoring the inside of piping processing equipment in chemical plants, or data transmission installed in the rolling process of steel plants, etc. Suitable for use in areas that receive repeated exposure.

In other words, when the original connector 5 is repeatedly heated and cooled to around 100°C or more, the adhesive peels off due to the difference in thermal expansion between the element 1Ii12 of the original fiber 1, the plug 6, and the adhesive. When the agent protrudes from the tip of the plug 6 due to thermal expansion, it is simultaneously extruded into the element @2.

This reduces the reliability of transmission.

However, by providing 25% glass pipe,
Since the element 2 is restrained by the glass pipe 25, it is possible to prevent the element @2 from protruding from the plug 6 even if it is heated or cooled.

According to the present invention, an optical connector that can be assembled easily and with high precision can be produced inexpensively and efficiently in a situation where optical fiber connections are required.

[Brief explanation of drawings]

Fig. 1 is a front sectional view showing the optical connector, Fig. 2 is a front sectional view showing the V section of the mold for molding the plug, Fig. 3 is a front sectional view of the plug, and Fig. 4 is the same as Fig. 3. Enlarged view of main parts,
Fig. 5 is a front sectional view of the sleeve, Fig. 6 is a characteristic diagram showing the relationship between the mating clearance between the sleeve and the plug, one-lug insertion/extraction force, and connection loss, and Fig. 7 is the relationship between the number of plug insertion/extraction times and connection loss. Figure 8 is a characteristic diagram showing the relationship between temperature and connection loss depending on the selection of plug and sleeve materials.
Is Fig. 9 another example of an optical connector? It is an enlarged view of the main part shown. 1... Optical fiber, 2... Element wire, 3...-
Next coat, 4... Secondary coat, 5... Optical connector, 6... Plug, 7... Hole,
8... Hole, 9... 7 lange, 10... Sleeve, 11... Through hole, 12... Guide part, 15... 7
Lunge, 14...screw, 15...cap nut, 16.
...7 langes, 17...through holes, 18゛°"
Screw・19...Spring, 2o...Clamp ring, 21..., Table cap, 25-0. Gala 8 via, 30...Fixed side mounting plate,
51... Lock bin, 52... Il board, 55...
Core, 34...core, 55...hole,
56...hole, 57...core bin,
58... Movable side template, 39... Core,
40...Groove, 41...Protrusion, 42...Ejector bin, 45...Core bin, 44...Synthetic resin, 45
... Fig. 3 Fig. 4 6 qi of the 5th bacterium o6 (k clear u2 people (μ7I) o 7A (d8) ) O90 Continued from page 1 0 Inventor Kiyohide Miyake Hitachi, Ltd., 5-1 Marunouchi-chome, Chiyoda-ku, Tokyo 0 Inventor Toshibe Kodama Co., Ltd. 5-1 Marunouchi-chome, Chiyoda-ku, Tokyo Inside Hitachi, Ltd.

Claims (1)

[Claims] t. A plug attached to the end of an optical fiber with an adhesive, a sleeve having screws formed on both ends of the outer circumferential surface so that the plug is inserted from both ends into the narrow part, and a sleeve on the inner circumferential surface. A light having a screw formed at one end to engage with the screw, a cap nut for fixing the plug to the sleeve, and a spring inserted into the outer periphery of the plug to be located between the plug and the cap nut. In the connector, the plug is provided with a core bin that is one to a few thinners larger than the outer diameter of the optical fiber in the center of the core that forms the tip of the plug, and a core that extends from the other end to one end of the core bin. An optical connector characterized in that it is molded from a synthetic resin using a mold that is attached to the sleeve, and the sleeve is molded from a synthetic resin having the same composition as the plug. 2. Claim 1 states that plugs and sleeves are formed using a composition in which 10 to 50 weight 1% of one camphor tree among glass beads, hollow glass bulbs, and quartz glass is added to polycarbonate as fibers. Characteristic optical funector 05 In claim 1, an epoxy resin,
Plugs and sleeves are made of a composition in which one of glass beads, hollow glass bulbs, and quartz glass is added at 50% by weight, preferably from 50 to 80% by weight.
An optical connector characterized in that: 4. The optical connector according to claim 1, characterized in that the outer diameter of the plug is 1 μm thick with respect to the inner diameter of the sleeve. 5. In claim 1, an optical fiber and 1
An optical connector characterized in that the adhesive for fixing the connector is an elongated adhesive having a viscosity of 20 poise or less. 6 In the first claim, the adhesive is an epoxy adhesive with a viscosity of 20 voices or less, and the adhesive is an epoxy adhesive with an average particle diameter of 50 ml of the clearance between the hole of 1 lag and the strand of the optical fiber. Or 70% alumina or aluminum hydroxide powder? 40-6r: An optical connector characterized by adding J wt%. 2. In claim 1, the optical fiber /((n
An optical connector characterized in that a glass pipe Y is inserted into the base of a bare wire, and the glass pipe is fixed to a plug together with an optical fiber. 8. In claim 2, is ethylene tetrafluoride used as a lubricant? An optical connector characterized in that a plug and a sleeve are formed of a composition containing 5 to 50% of the composition. 9. The optical connector 1 according to claim 2, characterized in that the plug and sleeve are formed of a composition to which 1 to 5 weight 6% molybdenum disulfide is added as a lubricant. 1α In claim 3, the plug and the sleeve are formed from a composition in which one to five Wk≦ of ethylene tetrafluoride, molybdenum disulfide, or graphite is added as an IW lubricant.tvi Optical connectors that become moldy. 11 Secondary coat and primary coat of Hikari 7 Aipa terminal?
A process of removing a predetermined length of each and cleaning the exposed primary cable and the outer periphery of the wire with an organic solvent, a process of inserting a cap nut and a spring into the optical fiber from the terminal from which the coating was removed, and a plug. a step of injecting a predetermined amount of adhesive into the hole of the plug, and a step of inserting a Hikari 7 Eyeper into the plug until the strand protrudes from the tip end surface of the plug before the adhesive injected into the plug hardens; After the adhesive has hardened and the plug and optical fiber have been fixed together, the process of cutting the strands protruding from the tip end of the plug and polishing the ends of the plug and the strands to the A side is the definition of an optical connector. Construction method. 12. In claim 11, the plug has a core bin that is 1 to several μnl thicker than the diameter of the strand of the original fiber to be connected, erected at the center of the core forming the tip end face of the plug, and the core A method of manufacturing an optical connector, characterized in that the optical connector is molded using a mold in which a movable core extending from the rear end of a plug is brought into contact with one end of the plug.