JPH0459615B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing an optical connector in which an optical fiber exposed from a cored optical fiber is fixed to a connector ferrule with solder.

[Prior Art] FIGS. 1 to 5 show optical connectors manufactured by conventional manufacturing methods. As shown in FIG. 1, the optical fiber at the end of the optical fiber core 1b is constructed by providing a buffer layer 3 and a coating layer 4 on the outside of an optical fiber 1a consisting of a core 1 and a cladding 2. A wire 1a is fixed to a connector ferrule 5. In addition, in FIG. 2, 2b is a polymer cladding.

Either fix the optical fiber 1a and the connector ferrule 5 with the adhesive 6 at the terminal part of the optical connector constructed in this way (see Fig. 1), or
As proposed in No. 170608, these metal films 7 are formed on the optical fiber 1a by vapor deposition of Au, Ni, etc., and the metal film 7 and the connector ferrule 5 are brazed (soldered) at the ends. ) portion 8 was formed and fixed by brazing (see Fig. 2). By the way, fixing using the adhesive 6 or fixing by brazing after depositing a metal film has the following drawbacks.

In other words, with the method of fixing with the adhesive 6, the long-term reliability of the adhesive 6 is poor, the heat resistance of the adhesive 6 is low at 80°C or less, the adhesive 6 requires curing time and installation time, and it is difficult to mass produce. There are disadvantages such as lack of properties, and the metal film 7
However, in the case of actual optical fiber cables, it is not possible to work by putting only the ends of the optical fibers into a vacuum deposition device, and it is not possible to work on the entire optical fiber cable or the drum. It has disadvantages such as poor workability because it has to be completely inserted, and even if it could be done, it would take a long time to do the work, which would be even more difficult in the case of multi-fiber optical fiber cables, and it would be expensive if it was plated with Au. It was hot.

In order to solve these drawbacks, conventional methods for manufacturing optical connectors as shown in FIGS. 3 to 5 have been proposed.

FIG. 3 is a cross-sectional view of an optical connector manufactured by the manufacturing method. Components that are the same as those in FIG. 1 are designated by the same reference numerals, and their explanations will be omitted. In the terminal portion of the optical connector shown in FIG. 3, the optical fiber wire 1a and the connector ferrule 5 are fixed with solder 9 whose main components are Sn and Pb, which is an easy fixing means.

This optical connector terminal portion is obtained by removing the buffer layer 3 and coating layer 4 from the end of the optical fiber core wire 1b, and applying solder 9 containing Sn and Pb as main components to the connector ferrule 5. After fixing, the optical fiber core wire 1b is additionally fixed with adhesive 6, and this fixing with solder 9 is the fourth
As shown in Figures A and B, the solder 9 is applied with vibrations such as ultrasonic waves indicated by the arrows in the figure, so that it adheres uniformly to the glass surface with a certain degree of adhesion. It is carried out at the same time. First, put the solder 9 in the center of the heater/solder tank 10.
Turn on the heater and melt solder 9. On the other hand, the connector ferrule 5 is provided with an air vent hole 11 and a V-groove 12 on the outer periphery of the tip, and the end surface is machined into a conical shape. The reason why the conical shape is formed is to make it easier for the solder 9 to enter through the gap between the optical fiber wire 1a and the inner diameter of the connector ferrule 5, and the V-groove 12 becomes uneven after the solder 9 is applied. The purpose is to cut off the tip. Also,
Connector ferrule 5 has a hole having a portion slightly larger than the optical fiber core wire 1b and a portion slightly larger than the outer diameter of the optical fiber wire 1a.
It is machined to be concentric with the outer diameter of. Insert the optical fiber 1a from which the buffer layer 3 and coating layer 4 at the terminal end of the optical fiber core 1b have been removed into the connector ferrule 5 that has been processed in this manner, and insert the optical fiber 1a from the tip of the connector ferrule 5 to an appropriate length. Just let it out. At this time, the optical fiber core wire 1b may be fixed to the connector ferrule 5 with adhesive 6 in advance so that it does not move, or the optical fiber core wire 1b may be fixed with adhesive 6 after fixing the optical fiber wire 1a with solder 9. Although it may be fixed in an auxiliary manner, it is preferable that the adhesive 6 has a quick curing time because it is efficient. Next, a cooling tube 13 is arranged around the connector ferrule 5 into which the optical fiber core 1b is inserted. When the tip of the connector ferrule 5 is heated, the cooling tube 13 spreads heat to the entire connector ferrule 5, and the adhesive 6 used auxiliary and the coating layer 4 such as a nylon jacket are heated. This is to prevent deformation or melting, and the refrigerant used is water, Freon gas, etc., which is circulated.

In this way, the connector ferrule 5 is surrounded by the cooling tube 13, the tip of the connector ferrule 5 is brought into contact with the solder bath 10 while cooling, and then the vibration f is applied from below the solder bath 10 with an arbitrary strength. For example, an ultrasonic vibration f is applied. This vibration f causes the solder 9
is adhered little by little at the same time to the circumferential surface of the cladding 2 of the optical fiber strand 1a and to the inner surface of the connector ferrule 5, and advances to the upper part of the connector ferrule 5. In this case, in order to prevent oxidation of the solder 9, an inert gas such as N is added around the connector ferrule 5.
Smooth soldering can be achieved by creating an atmosphere of gas or Ar gas mixed with a little O and applying ultrasonic vibrations f. Solder 9 is air vent hole 1
1, gently pull the connector ferrule 5 away from the solder bath 10. The solder 9 starts solidifying as soon as it is pulled up, and reaches the initial hardness of the solder 9 within a few seconds. Next, as shown in FIG. 4B, the tip of the connector ferrule 5 is cut off from the position of the V-groove 12, and the cut-off connector ferrule end face 14 is mirror polished. In the same figure, 14a is the cut-off end of the connector ferrule 5. Figure 5 A and B show multiple optical fiber cores 1
This is another conventional example in which the connector ferrule 5 and the connector ferrule 5 are fixed with solder 9 in the same manner as in the above case.

This conventional optical connector fixing method of fixing the optical fiber wire and the connector ferrule with solder is also disclosed in Utility Model Application Publication No. 58-170608 and Japanese Patent Application Publication No. 59-129816. According to this method, the soldering work can be done very easily within one minute, which not only greatly reduces the time required to fix the optical fiber to the connector ferrule, but also reduces the amount of solder used. Depending on the method, it is possible to obtain an optical connector with extremely excellent heat resistance.If mirror polishing is performed, a highly reliable optical connector in which the optical fiber 1a and the connector ferrule 5 are fixed with solder 9 can be obtained. Wear. In other words, since solder 9 is used, not only can the connector ferrule 5 be installed on-site in a short time, but also solder 9 has superior heat resistance compared to general adhesive 6, and has better heat resistance and long-term reliability. Not only that, but it is also suitable for mass production.In the case of adhesive 6, the work cannot be re-done, but in the case of solder 9, it can be easily removed as many times as you like by raising the temperature above the melting point of the solder 9. It is possible to achieve the following effects.

[Problems to be Solved by the Invention] However, in the conventional optical connector manufacturing method described above, since solder melted at, for example, 350°C is used, stress caused by thermal contraction of the connector ferrule during cooling causes the solder to deteriorate. There is a drawback that the optical fiber in the ferrule is slightly bent due to thermal distortion, which significantly increases transmission loss.

The present invention has been made in view of the above points,
To provide a method for manufacturing an optical connector, which can easily fix an optical fiber core wire and a connector ferrule with good workability, and can suppress the occurrence of small bends due to thermal distortion of the optical fiber wire at the terminal end of the connector. It is an object.

[Means for Solving the Problems] The gist of the present invention is to expose the optical fiber from a cored optical fiber in which a buffer layer and a coating layer are provided on the outside of the optical fiber consisting of a core and a glass cladding. After that, the optical fiber wire is inserted into the hole of the connector ferrule, and the optical fiber wire is fixed to the connector ferrule by the solder flowing into the hole of the connector ferrule. In the method, the optical fiber wire is brought into contact with a melt of high melting point solder to form a coating of the high melting point solder on the outer periphery of the optical fiber wire, and then the above-mentioned method having the high melting point solder coating is applied. The optical fiber is coated with the high melting point solder by inserting the optical fiber wire into the hole of the connector ferrule and using the solder having a lower melting point than the high melting point solder flowing into the hole of the connector ferrule. The purpose is to fix the wire to the connector ferrule.

[Example] The present invention will be described below based on the illustrated example.

FIG. 6 shows an embodiment of an optical connector made according to the present invention. In this embodiment, the solder is composed of two types of solder 9a and 9b having different melting points.
In this case, the optical fiber wire 1a at the end of the optical fiber core wire 1b and the connector ferrule 5 are soldered with solder 9a,
9b so that it can be easily fixed.

That is, solder 9a is formed on the circumferential surface of the optical fiber 1a in advance, and after the formation, it is fixed to the connector ferrule 5 with solder 9b having a lower melting point than this solder 9a. I proceeded as described in . That is, as shown in FIGS. 7A, B, and C, the buffer layer 3 and the coating layer 4 at the end of the optical fiber core 1b are
The stripped optical fiber 1a is inserted into a heater/solder tank 10a, and a high-precision hole 10b with dimensions slightly larger than the outer diameter of the optical fiber 1a is provided in the center of the solder tank 10a. There is. The solder 9a in the solder tank 10a is melted in advance using a heater. While the solder bath 10a is subjected to ultrasonic vibration f at a desired strength, the optical fiber 1a is gently inserted into the solder bath 10a from directly above the solder bath 10a through the high-precision hole 10b, and is held for several seconds after being inserted. After the elapse of time, the optical fiber core wire 1b is pulled up at a constant speed.
This operation is carried out in an inert gas atmosphere as in the previous case. By doing so, the high-precision hole 10b serves as a molding die for the solder 9a, so that a uniform thin solder 9 is applied around the optical fiber 1a as shown in FIG. 7C.
A layer a is formed, and the strength of the optical fiber strand 1a is improved. On the other hand, the connector ferrule 5 is pre-processed to have a hole into which the optical fiber core 1b is inserted and an inner diameter slightly larger than the outer diameter obtained by forming a layer of solder 9a, and FIG. As shown in B, warm it up with the heater 15. In addition, in FIG. 7B, 10c has solder 9a on its circumferential surface.
This is a high-precision hole into which the optical fiber strand 1a formed with is inserted. In the connector ferrule 5, there is solder 9 formed on the circumferential surface of the optical fiber core 1a.
Solder 9b having a lower melting point than solder a is melted. The optical fiber wire 1a to which the solder 9a is attached is gently inserted into the melted solder 9b. When the optical fiber 1a comes out from the tip of the connector ferrule 5, the heater 15 is turned off. In this way, the solder 9b solidifies after a few seconds, and then the adhesive 6 is injected through the gap between the connector ferrule 5 and the coating layer 4 of the optical fiber core 1b, as shown in FIG. 7C. In this state, the portion protruding beyond the connector ferrule end face 14 is cut off from the connector ferrule end face 14, and the connector ferrule end face 14 is mirror-polished. As described above, according to this embodiment, the optical fiber strand 1a at the end of the optical fiber core 1b and the connector ferrule 5 can be easily fixed with the solders 9a and 9b having different melting points. In addition, even if the connector ferrule thermally shrinks during cooling, the optical fiber strand 1a may be damaged by the high melting point solder 9a.
Because it is reinforced, small bends will not occur. Note that the solder 9a preferably has a melting point of 350°C or lower.

Although the adhesive 6 is used in this embodiment, if the coating layer 4 of the optical fiber core 1b is mechanically caulked and fixed at the end of the connector ferrule 5 on the insertion side of the optical fiber core 1b, Adhesive 6 may not be used.

FIG. 8 shows yet another embodiment of the invention. This embodiment uses two types of solder 9a and 9b with different melting points, as in the case described above, and the figure shows a case in which the light emitting or light receiving element 16 and the optical fiber element 1a are efficiently connected and A sealed package is shown. First, the optical fiber wire 1a from which the buffer layer and the coating layer have been removed is pre-plated with solder 9a as described above, and then solder 9a is applied to the cap 17 on the optical fiber wire 1a. The cap 17 is fixed with solder 9b having a melting point lower than that of the cap 17, and the cap 17 is aligned with the light emitting or light receiving element 16, and ring welded at the best bonding point to form an airtight structure. In addition, in the same figure, 18 is a stem. Even when the optical fiber core wire is fixed to the cap 17 in this manner, fixing using the solders 9a and 9b can be applied.

[Effects of the Invention] As explained above, an optical fiber whose outer periphery has been coated with high melting point solder is inserted into the hole of the connector ferrule, and solder having a lower melting point than the high melting point solder is inserted into the hole of the connector ferrule. According to the method of manufacturing an optical connector of the present invention in which the optical fiber is fixed by the method of the present invention, it is not necessary to perform extremely troublesome processing such as vapor deposition on the optical fiber wire, so the optical connector can be easily manufactured in a short time and with good workability. In addition, by forming a coating of high melting point solder on the outer periphery of the optical fiber in advance before inserting and fixing it into the connector ferrule, the high melting point solder coating is applied to the optical fiber. It has a reinforcing effect and has the excellent effect of preventing the optical fiber from being bent slightly due to thermal strain when the connector ferrule is cooled.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of an optical connector manufactured by a conventional manufacturing method, Figure 2 is a cross-sectional view of an optical connector manufactured by a conventional manufacturing method, and Figure 3 is a cross-sectional view of an optical connector manufactured by a conventional manufacturing method. 4A and 4B are cross-sectional views of the connector; A is a perspective view of the conventional example; A is a perspective view showing the optical fiber wire inserted into the solder bath;
5A and 5B are cross-sectional views of the main parts of the terminal portion of the optical connector showing a state filled with solder, A is a perspective view, B is a front view, and FIG. 7 is a cross-sectional view of an embodiment of the optical connector made according to the present invention, and FIGS. 7A, B, and C are also cross-sectional views of an embodiment of the optical connector according to the present invention. Cross-sectional view, B is a cross-sectional view showing a state in which low melting point solder is melted in the connector ferrule, C is a state in which a soldered optical fiber wire is inserted into a connector ferrule in which low melting point solder is melted. FIG. 8 is a cross-sectional view showing a state in which an optical connector and an optical element of another embodiment of the optical connector made according to the present invention are coupled. DESCRIPTION OF SYMBOLS 1: Core, 1a: Optical fiber strand, 1b: Optical fiber core, 2: Clad, 2b: Polymer clad, 3: Buffer layer, 4: Covering layer, 5: Connector ferrule, 6: Adhesive, 9, 9a : Handa, 9
b: Solder with a lower melting point than 9, 9a, 10, 10
a: heater and solder tank, 10b, 10c: high precision hole, 11: air vent hole, 12: V groove, 13: cooling tube, 14: connector ferrule end face, 15: heater, 16: light emitting or light receiving element, 17: Cap.

Claims (1)

[Claims] 1. After exposing the optical fiber from the optical fiber core wire, which is provided with a buffer layer and a coating layer on the outside of the optical fiber wire consisting of a core and a glass cladding, the optical fiber wire is inserted into the hole of the connector ferrule. In the method for manufacturing an optical connector, the optical fiber wire is fixed to the connector ferrule by solder that is inserted and allowed to flow into the hole of the connector ferrule. Forming a coating of the high melting point solder on the outer periphery of the optical fiber by bringing it into contact with a melt, and then inserting the optical fiber having the high melting point solder coating into the hole of the connector ferrule. The optical fiber wire having the high melting point solder coating is fixed to the connector ferrule by solder having a lower melting point than the high melting point solder that is flowed into the hole of the connector ferrule. A manufacturing method for optical connectors.