JP2000098187A - Optical ferrule and method of fixing optical fiber to optical ferrule - Google Patents

Abstract

An optical ferrule capable of fixing an optical fiber to an optical fiber insertion hole in a short time with good workability, and enabling optical connection of the fixed optical fiber with low connection loss. SOLUTION: A plurality of optical fiber insertion holes 3 for inserting and fixing an optical fiber are provided, and an optical fiber insertion portion 5 having an optical fiber insertion groove 2 is provided on both sides of the optical fiber insertion hole 3, and the optical fiber insertion hole 3 is provided. Is formed smaller than the outer diameter of the optical fiber inserted into the optical fiber insertion hole 3 at normal temperature. Optical ferrule 1 has a crystallinity of at least 10
% Of a crystalline resin and a conductive filler having a volume resistivity of 50% at room temperature.
Ωcm or less, has a positive temperature coefficient characteristic that the volume resistivity increases as the temperature increases, and has a switching temperature of about 150 ° C. higher than the operating temperature of the optical ferrule, and furthermore, at a switching temperature or higher. The volume resistivity is 100 Ω · cm or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an optical communication system,
The present invention relates to an optical ferrule for optically connecting an optical fiber simply and accurately and a method for fixing an optical fiber to the optical ferrule.

[0002]

2. Description of the Related Art In the field of optical communication, an optical ferrule is used to optically connect optical fibers to each other. FIG. 8 shows an example of a conventional optical ferrule called a mechanical splice. Are indicated by. The optical ferrule 1 has an optical ferrule body 10 composed of an upper plate member 41 and a lower plate member 42 as shown in FIG. 5A, and a fitting 43 as shown in FIG. The lower plate member 42 has a plurality of V-shaped grooves 39 formed therein. The upper plate member 41 and the lower plate member 42 are formed of, for example, epoxy resin.

When an optical fiber is fixed to such an optical ferrule 1, for example, the coating on the distal end side of an optical fiber tape in which a plurality of optical fibers are juxtaposed is removed to expose a bare optical fiber. After the end faces of the plurality of bare optical fibers are cut by the precision cutter, the bare optical fibers are inserted from both ends of the V-shaped groove 39 of the lower plate member 42 along the V-shaped groove 39. At this time, the end faces (connection end faces) of the bare optical fibers inserted from both ends of the V-shaped groove 39 are physically brought into contact (contact).

In this state, the upper plate member 41 is assembled on the lower plate member 42 and the bare optical fiber is connected to the lower plate member 4.
2 and the upper plate member 41, and in this state, the upper plate member 41 and the lower plate member 42 are fixed by metal fittings 43 as shown in FIG. An optical fiber is fixed to the optical ferrule 1. The upper plate member 41 and the lower plate member 42 may be fixed using a member such as a clip having a spring force instead of the metal fitting 43.

FIG. 7 shows another example of an optical ferrule.
Optical connector-type optical ferrules as shown in FIG. In this type of optical ferrule, one or more pairs of pins 26 for positioning are inserted when the optical ferrule 1 is connected to the optical component of the connection partner (the one shown in FIG.
Paired) pin insertion holes 25 are provided. A plurality of optical fiber insertion holes 3 are formed at intervals with these pin insertion holes 25, and the optical fiber insertion holes 3 are sandwiched between the pin insertion holes 25. One end is exposed on the connection end face 27 side of the optical ferrule 1.
An optical fiber tape insertion portion 30 is formed on the other end side of the optical fiber insertion hole 3 (on the side opposite to the connection end surface 27 of the optical ferrule 1).

When fixing the optical fiber to the optical ferrule 1, similarly to the above, the coating on the distal end side of the optical fiber tape core wire 29 is removed to expose the bare optical fibers, and the end faces of the plurality of bare optical fibers are removed. Cut with a precision cutter. Then, the optical fiber ribbon 29 is inserted into the optical fiber insertion portion 2.
Then, the bare optical fiber at the distal end of the optical fiber ribbon 29 is inserted into the optical fiber insertion hole 3, and the bare optical fiber and the optical fiber ribbon 29 are fixed to the optical ferrule 1 with an adhesive. In the drawing, reference numeral 28 denotes a rubber boot, and the rubber boot 28 plays a role of protecting an inserted portion of the optical fiber ribbon 29 into the optical ferrule 1.

[0007]

However, a mechanical splice type optical ferrule 1 as shown in FIG.
The upper plate member 41, the lower plate member 42, and the upper plate member 4
Since the optical ferrule 1 has a fixing member such as a metal fitting 43 for fixing the first ferrule 1 and the lower plate member 42, the number of components of the optical ferrule 1 increases, and there is a problem that assemblability and workability are poor. .

[0008] The optical ferrule 1 is fixed with an optical fiber juxtaposed to a multi-core optical fiber tape with its tip cut by a precision cutter or the like. Rarely have the same length,
Since the length of each optical fiber is often slightly different, even if the optical fibers are simply made to face each other along the V-groove 39 and optically connected, there is not much contact between all the optical fiber connection end faces. Therefore, there is a problem that the connection loss between the optical fibers increases.

On the other hand, an optical ferrule 1 as shown in FIG.
In the case of, the optical fiber of the optical fiber ribbon 29 is exposed at the connection end face 27 of the optical ferrule 1, so that the connection loss between the optical fibers can be reduced.
When fixing the optical fiber and the optical fiber tape core wire 29 to the optical ferrule 1, it takes 10 minutes even for a simple type until the adhesive is cured, and it takes an hour for a precision type. The workability of fixing the optical fiber to the optical ferrule 1 is poor. In particular, when connecting work on an elevated location such as on a telephone pole, it is extremely difficult to use the optical ferrule 1 of the type shown in FIG.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to fix an optical fiber to an optical ferrule in a short time with good workability. An optical ferrule capable of optically connecting an optical fiber with low connection loss and a method of fixing an optical fiber to the optical ferrule.

[0011]

In order to achieve the above-mentioned object, the present invention has the following structure to solve the problem. That is, the first optical ferrule
Is an optical ferrule having one or more optical fiber insertion holes for inserting and fixing an optical fiber, the optical ferrule having a crystalline resin having a crystallinity of at least 10% or more and a conductive filler. Formed of a composite material,
The composite material has a positive temperature coefficient characteristic in which the volume resistivity increases as the temperature increases below 50 Ω · cm at room temperature at room temperature, and at a temperature exceeding the upper limit of the operating temperature range of the optical ferrule. It has a switching temperature, and the volume specific resistance at the switching temperature or higher is at least 100 Ωcm or more, and the inner diameter of the optical fiber insertion hole at room temperature is smaller than the outer diameter of the optical fiber inserted into the optical fiber insertion hole. This is a means for solving the problem with a small-sized configuration.

Further, the second invention of the optical ferrule is a means for solving the problem with a configuration in which the switching temperature is 100 ° C. or more in addition to the configuration of the first invention.

Further, the third invention of the optical ferrule is as follows.
In addition to the configuration of the first or second aspect of the present invention, the optical fiber insertion hole is formed by a through hole, and the formation region of the optical fiber insertion hole is formed on both sides sandwiching the optical fiber insertion hole in the longitudinal direction. An optical fiber insertion portion for inserting an optical fiber into each optical fiber insertion hole is formed, and the problem is caused by a configuration in which an optical fiber is inserted from both sides of the optical fiber insertion hole through these optical fiber insertion portions. It is a means to solve.

Further, the fourth invention of the optical ferrule is as follows.
In addition to the configuration of the third aspect, the optical fiber insertion portion has an optical fiber insertion groove communicating with the optical fiber insertion hole and guiding an optical fiber inserted into the optical fiber insertion hole to the optical fiber insertion hole. The formed configuration is a means for solving the problem.

Further, the fifth invention of the optical ferrule is as follows.
In addition to the configuration of the first or second aspect of the present invention, the optical ferrule is formed with one or more pairs of pin insertion holes for inserting positioning pins for connecting the optical ferrule to an optical component on the other side of connection. An optical fiber insertion hole is formed at an interval from the pin insertion hole so that the optical fiber insertion hole is sandwiched between the pin insertion holes. This is a means for solving the problem with a configuration exposed on the connection end face side of the ferrule.

Further, the sixth invention of the optical ferrule is as follows.
In addition to the structure of any one of the first to fifth aspects of the present invention, a means for solving the problem has a structure in which an electrode insertion hole for inserting an electrode used for flowing a current through an optical ferrule is formed. I have.

Further, the seventh invention of the optical ferrule is as follows:
In addition to the structure of any one of the first to sixth aspects of the present invention, a means for solving the problem has a structure in which an electrode used for flowing a current to the optical ferrule is insert-molded.

Further, the eighth invention of the optical ferrule is as follows:
In addition to the configuration of any one of the first to seventh aspects of the present invention, the optical ferrule is provided with an exterior member that covers the outer periphery of the optical ferrule and prevents expansion of the optical ferrule within the operating temperature range of the optical ferrule. In this case, the linear expansion coefficient of the exterior member has a value equal to or less than the linear expansion coefficient of the optical ferrule.

Further, the first invention of a method for fixing an optical fiber to an optical ferrule is that the inner diameter of the optical fiber insertion hole of the optical ferrule is increased by heating the optical ferrule. Insert the optical fiber into the optical fiber insertion hole in a state expanded to the outer diameter or more, then reduce the inner diameter of the optical fiber insertion hole to a diameter smaller than the outer diameter of the optical fiber by cooling the optical ferrule afterwards. In this case, the optical fiber is fixed to the optical fiber insertion hole by means of a means for solving the problem.

Further, in the second invention of the method of fixing an optical fiber to an optical ferrule, in addition to the structure of the first invention of the fixing method, the optical ferrule is formed of a conductive material. Electrodes are arranged on both sides of the optical fiber insertion hole forming region of the optical ferrule, and a current is passed through the electrodes to heat the optical ferrule, thereby solving the problem.

In the present invention having the above structure, the optical ferrule is formed of a composite material having a crystalline resin having a crystallinity of at least 10% or more and a conductive filler. In the present specification, room temperature is 25 Ω · cm or less at 25 ° C.). Therefore, when a voltage is applied to the optical ferrule and a current is passed, the optical ferrule generates heat. The positive temperature coefficient characteristic (PT
C: Positive TempertureCoef
and the volume resistivity above the switching temperature is at least 100 Ω · cm, so that the resistance increases rapidly at the switching temperature near the melting point of the material, and the temperature does not further rise. Demonstrate self-temperature control function.

When the switching temperature is reached, the volume of the resin crystal expands due to the partial melting of the resin crystal, the current path decreases, and the current flows only to the extent that the current keeps the temperature. This is considered to be a phenomenon in which heat radiation occurs to maintain balance. As in the optical ferrule of the present invention, the volume resistivity at the switching temperature or higher is at least 10%.
If it is 0 Ω · cm or more, the effect of preventing temperature rise by the self-temperature control function is reliably exhibited, and there is no possibility that the temperature of the optical ferrule exceeds the switching temperature and rises.

In the optical ferrule of the present invention, one or more optical fiber insertion holes for inserting and fixing an optical fiber are formed, and the inside diameter of the optical fiber insertion hole at room temperature is inserted into the optical fiber insertion hole. Although formed to be smaller than the outer diameter of the optical fiber, the volume expansion (thermal expansion) at the switching temperature expands the optical fiber insertion hole of the optical ferrule, and allows the optical fiber to be inserted.

Therefore, for example, using the method of fixing an optical fiber to an optical ferrule of the present invention, the optical ferrule is heated by applying a current to electrodes disposed on both sides of the optical ferrule, and the inner diameter of the optical fiber insertion hole of the optical ferrule is increased. The optical fiber is inserted through the optical fiber insertion hole while the optical fiber is expanded beyond the outer diameter of the optical fiber inserted through the optical fiber insertion hole.After that, the power to the electrode is stopped and the optical ferrule can be returned to room temperature. If, for example, the volume shrinkage of the optical ferrule occurs, it becomes possible to reduce the inner diameter of the optical fiber insertion hole to a diameter smaller than the outer diameter of the optical fiber, thereby making the optical fiber very easily and reliably. , Can be fixed to the optical fiber insertion hole of the optical ferrule.

Further, since the volume shrinkage of the optical ferrule due to heating after returning to the switching temperature of the optical ferrule or more and then cooling (returning to normal temperature) also occurs in the longitudinal direction of the optical fiber insertion hole, the optical ferrule passes through the optical fiber insertion hole. Optical fiber insertion portions for inserting optical fibers into the optical fiber insertion holes are formed on both sides of the optical fiber insertion hole in the longitudinal direction of the optical fiber insertion hole. If the optical fiber is inserted from both sides of the optical fiber insertion hole via the insertion portion, the physical contact force between the optical fibers inserted from both sides of the optical fiber insertion hole is increased, and the connection between the optical fibers is increased. Loss can be reduced.

Further, since the optical ferrule of the present invention has a switching temperature at a temperature exceeding the upper limit of the operating temperature range of the optical ferrule, the volume expansion phenomenon caused by the self-temperature control function is limited to the operating temperature range of the optical ferrule. Since this occurs at a temperature exceeding the upper limit value, the phenomenon that the optical fiber insertion hole expands as described above does not occur at the operating temperature of the optical ferrule, and the state where the optical fiber is securely fixed in the optical fiber insertion hole is maintained. You.

As described above, in the present invention, the optical fiber can be easily fixed to the optical ferrule in a short time, and the fixed optical fiber can be optically connected with low connection loss. The above problem is solved.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same reference numerals are given to the same parts as those in the conventional example, and the duplicate description thereof will be omitted. FIG. 1 shows a first embodiment of an optical ferrule according to the present invention. 2A is a perspective view of the optical ferrule, FIG. 2B is a front view of the optical ferrule, FIG. 2C is a plan view of the optical ferrule, and FIG. Side views of the optical ferrules are respectively shown.

As shown in these figures, the optical ferrule 1 of this embodiment has a convex side surface and four optical fiber insertion holes 3 penetrating therethrough. A hole forming portion 4 which is an area where these optical fiber insertion holes 3 are formed.
Optical fiber insertion portions 5 for inserting optical fibers into the optical fiber insertion holes 3 are formed on both sides of the optical fiber insertion holes 3 in the longitudinal direction of the optical fiber insertion holes 3, respectively. Have optical fiber insertion holes 3 respectively.
And an optical fiber insertion groove 2 for guiding an optical fiber inserted into the optical fiber insertion hole 3 to the optical fiber insertion hole 3.
Are formed four by four. The optical ferrule 1 of the present embodiment has a configuration in which an optical fiber is inserted from both sides of the optical fiber insertion hole 3 via the optical fiber insertion section 5.

The optical ferrule 1 of this embodiment is formed of a composite material having a polyphenylene sulfide resin as a crystalline resin having a crystallinity of at least 10% and acetylene black as a conductive filler. Specifically, 10 parts by weight of acetylene black is blended with 100 parts by weight of polyphenylene sulfide resin, and 50 parts by weight of spherical silica as a filler is blended.

This composite material has a volume resistivity of 10 at room temperature.
In Ω · cm, it has a positive temperature coefficient characteristic in which the volume resistivity increases as the temperature increases, and at a temperature exceeding the upper limit of the operating temperature range of the optical ferrule 1 (for example, −40 ° C. to 80 ° C.). The composite material has a switching temperature of about 150 ° C., and the volume resistivity above the switching temperature of the composite material is 100 Ω · cm or more (for example, about 1000 Ω · c
m). The inner diameter of the optical fiber insertion hole 3 at room temperature is 124 μm, which is smaller than the outer diameter (125 μm) of the optical fiber inserted into the optical fiber insertion hole 3.

When the optical ferrule 1 of this embodiment is manufactured, for example, the composite material is kneaded in the above-described amount to form a pellet, and the pellet is injection-molded to form an optical ferrule having a shape as shown in FIG. After forming 1, the resin of the composite material is crosslinked by, for example, heating with an electron beam.

At the time of the injection molding, the molding pin for forming the optical fiber insertion hole 3 and the optical fiber insertion groove 2 is the same molding pin. When the mold is closed, the molding pin is slid into the mold. Then, the resin is injected in a state where the molding pin is supported by the formation region of the optical fiber insertion hole 3 and the formation region of the optical fiber insertion groove 2, and then, when the mold is opened, the molding pin comes off the resin molded body. To do.
If the outer diameter of the molding pin is, for example, 127 μm,
After the injection molding, when the optical ferrule 1 becomes normal temperature,
As described above, the inner diameter of the optical fiber insertion hole 3 is 124 μm.

The optical ferrule 1 of this embodiment is manufactured as described above and is configured as shown in FIG. 1. When an optical fiber is fixed to the optical ferrule 1, as shown in FIG. A voltage of 9 V DC is applied to the optical ferrule 1 by using an energizing jig to energize the optical ferrule 1.
While heating the optical fiber, the optical fiber is inserted into the optical fiber insertion hole 3. In FIG. 6, reference numeral 31 denotes a main body of the energizing jig. The optical ferrule 1 is housed in the ferrule housing part 33 of the energizing jig, and an optical fiber is introduced from the optical fiber introducing part 34. Then, the switch 36 of the power supply 35 is turned on, and a current flows from the electrode 32 to heat and supply electricity.

Then, since the optical ferrule 1 of this embodiment is a conductive material having a volume resistivity of 10 Ω · cm at room temperature, it generates heat by the above-mentioned energization. It has a positive temperature coefficient characteristic (PTC characteristic) in which the volume resistivity increases, and has a switching temperature near the melting point of the material (about 1 in the present embodiment).
Since the volume resistivity at 50 ° C. or more is 100 Ω · cm or more, the self-temperature control that the resistance rapidly increases at the switching temperature and the temperature does not further rise is surely exhibited, and the optical ferrule 1 is formed. The volume of the crystal of the resin to be melted partially expands, and the inner diameter of the optical fiber insertion hole 3 increases to be larger than the outer diameter of the optical fiber inserted into the optical fiber insertion hole 3, and the insertion of the optical fiber becomes difficult. Will be possible.

Then, the end of the bare optical fiber (optical fiber) exposed by removing the coating of the optical fiber ribbon is cut by a precision cutter, and the optical fiber is inserted into the optical fiber insertion portions 5 on both sides of the optical fiber insertion hole 3. And the optical fiber into the optical fiber insertion groove 2
And inserted through the optical fiber insertion hole 3 from both directions so that the optical fiber connection end faces substantially abut each other in the optical fiber insertion hole 3.

After that, when the optical ferrule 1 is returned to normal temperature,
The volume shrinkage of the optical ferrule 1 occurs, and the inner diameter of the optical fiber insertion hole 3 is reduced to a diameter smaller than the outer diameter of the optical fiber,
Thereby, the optical fiber is fixed to the optical fiber insertion hole 3 of the optical ferrule 1. When the optical ferrule 1 is heated to a switching temperature or higher and then returned to room temperature, the volume shrinkage of the optical ferrule 1 also occurs in the longitudinal direction of the optical fiber insertion hole 3, so that the optical ferrule 1 is inserted into each optical fiber insertion hole 3 from both directions. Even if an interval is formed between the connection end faces of the four pairs of optical fibers, the interval becomes smaller due to the volume shrinkage of the optical ferrule 1, and the physical contact force between the optical fibers increases.

According to this embodiment, the inner diameter of the one or more optical fiber insertion holes 3 for inserting and fixing the optical fibers at room temperature is smaller than the outer diameter of the optical fibers inserted into the optical fiber insertion holes 3. Although formed, the optical ferrule 1 has the PTC characteristic, and the volume specific resistance at the switching temperature or higher is 100 Ω · cm or higher, and the optical ferrule 1 reliably performs the self-temperature control function. Due to the volume expansion (thermal expansion) at the switching temperature, the optical fiber insertion hole 3 of the optical ferrule 1 expands above the switching temperature, and the optical fiber can be inserted. In this state, the optical fiber is inserted into the optical fiber insertion hole 3. By inserting the optical ferrule back to room temperature and reducing the inner diameter of the optical fiber insertion hole 3 to a diameter smaller than the outer diameter of the optical fiber, very easily and Indeed, it is possible to fix the optical fibers into the optical fiber insertion hole 3.

Further, since the volume shrinkage of the optical ferrule 1 caused by heating to a switching temperature of the optical ferrule 1 or higher and then cooling (returning to normal temperature) also occurs in the longitudinal direction of the optical fiber insertion hole, as described above, The physical contact force between the optical fibers inserted into the optical fiber insertion hole 3 from both directions can be increased, and the optical connection loss between the optical fibers can be reduced.

Actually, when a single mode optical fiber was inserted into the optical ferrule 1 of this embodiment and the connection loss between the single mode optical fibers was measured, the average connection loss was about 0.2 dB.

Further, according to this embodiment, the optical fiber insertion portions 5 are formed on both sides of the hole forming portion 4 in which the optical fiber insertion hole 3 is formed in the longitudinal direction of the optical fiber insertion hole 3. In addition, it is very easy to insert an optical fiber into the optical fiber insertion hole 3,
In particular, since the optical fiber insertion groove 2 is formed in the optical fiber insertion portion 5 so as to communicate with the optical fiber insertion hole 3, the insertion of the optical fiber into the optical fiber insertion hole 3 can be performed more easily and accurately. be able to.

Further, the optical ferrule 1 of this embodiment is
Has a self-temperature control function that functions reliably as described above, and performs self-temperature control. For example, by simply energizing the optical ferrule 1 using an energizing jig as shown in FIG. The operation of fixing the optical fiber to the optical fiber insertion hole 3 is very difficult because the fiber can be securely inserted into the optical fiber insertion hole 3 without any need for a heating device, a temperature control circuit, a sensor, and the like. It can be performed well.

Further, a power supply for supplying power to the optical ferrule 1 is sufficient because, for example, a dry battery can be used.
The energizing jig as shown in FIG. 6 can also be reduced in size, so that the work space for fixing the optical fiber to the optical ferrule 1 is small, and the work of transporting the energizing jig can be easily performed. For example, it is also possible to easily connect the optical fibers to each other by fixing the optical fibers to the optical ferrule 1 on an elevated or the like.

Further, the optical ferrule 1 of this embodiment is
Has a switching temperature that exceeds the upper limit of the operating temperature range of the optical ferrule 1, so that the volume expansion phenomenon caused by the self-temperature control function occurs at a temperature that exceeds the upper limit of the operating temperature range of the optical ferrule 1. At the operating temperature of the optical ferrule 1, the phenomenon that the optical fiber insertion hole 3 expands as described above does not occur, and the state in which the optical fiber is securely fixed to the optical fiber insertion hole 3 can be maintained. Thus, the reliability of the optical connection between the optical fibers can be maintained for a long time.

Actually, as described above, a single-mode optical fiber is inserted and fixed in the optical ferrule 1 of this embodiment, and the single-mode optical fiber fixed at the operating temperature of -40 ° C. to 80 ° C. The measurement of the connection loss variation between them was within 0.2 dB, which was a value that was practically acceptable.

Further, according to this embodiment, unlike the conventional mechanical splice type optical ferrule 1 as shown in FIG. 8, the number of parts is small, and for example, it is very simple to use injection molding. Can be manufactured.

As a comparative example of this embodiment, FIG.
In the structure shown in the figure, polyphenylene sulfide resin 100
The energization was applied to the optical ferrule 1 made of a material in which 20 parts by weight of oil furnace black and 50 parts by weight of spherical silica were blended with respect to the parts by weight. 1000Ω · c
m, and no heat was generated by energization, so that the diameter of the optical fiber insertion hole 3 could not be increased and the optical fiber could not be inserted into the optical fiber insertion hole 3 as in the present embodiment. Was.

Next, a description will be given of a second embodiment of the optical ferrule according to the present invention. The second embodiment is substantially the same as the first embodiment, and the difference between the second embodiment and the first embodiment is that the composite material forming the optical ferrule 1 The composition was formed by the following composition. That is, the composite material forming the optical ferrule 1 of the second embodiment is a conductive filler with respect to 100 parts by weight of a high-density polyethylene resin having a crystallinity of at least 10% or more. 50 parts by weight of oil furnace black,
It is formed by blending 20 parts by weight of spherical silica as a filler.

This composite material has a volume resistivity of 5Ω at room temperature.
Cm, a temperature having a positive temperature coefficient characteristic in which the volume resistivity increases as the temperature increases, and which exceeds the upper limit of the operating temperature range of the optical ferrule 1 (for example, −40 ° C. to 80 ° C.) It has a switching temperature of about 118 ° C., and the composite material has a volume resistivity above the switching temperature of 100 Ω · cm or more.

The second embodiment is configured as described above. In the second embodiment, similarly to the first embodiment, the optical ferrule 1 starts self-temperature control at about 118 ° C. At this point, the optical ferrule is manufactured by being inserted into the optical fiber insertion hole 3 of the optical fiber.
The optical fiber is inserted into the optical fiber, and the same effect can be obtained.

When a single mode optical fiber was actually inserted and fixed in the optical ferrule 1 of the present embodiment as in the first embodiment, the connection loss between the single mode optical fibers was measured. The average connection loss was about 0.2 dB, and the connection loss fluctuation range from -40 ° C. to 80 ° C. was 0.35 dB, which was a value that was practically acceptable.

FIG. 3 is a perspective view showing a third embodiment of the optical ferrule according to the present invention. The structure of the optical ferrule 1 of the third embodiment is substantially the same as the structure of the optical ferrule 1 of the first embodiment, and the optical ferrule 1 of the third embodiment is different from that of the first embodiment. What is different from the optical ferrule 1 is that an electrode insertion hole 6 for inserting an electrode used to flow a current through the optical ferrule 1 is provided on both sides of a region where the optical fiber insertion hole 3 is formed.
Is formed.

The third embodiment is configured as described above, and the third embodiment is manufactured in substantially the same manner as the first embodiment. In the third embodiment, since the electrode insertion hole 6 is formed in the optical ferrule 1,
When the optical fiber is fixed to the optical ferrule 1, the optical ferrule 1 is heated by heating the optical ferrule 1 at 150 ° C. When the self-temperature control is started, the optical fiber is inserted into the optical fiber insertion hole 3 and then fixed by returning the temperature to room temperature, as in the first embodiment.

The third embodiment can also provide substantially the same effects as those of the first embodiment. In addition, this third
In the embodiment, the electrode insertion hole 6 is formed, and the electrode rod is inserted into the electrode insertion hole 6 so that the optical ferrule 1 can be energized and heated. The optical ferrule 1 can be heated using a simple energizing jig, and the inner diameter of the optical fiber insertion hole 3 can be easily enlarged by energizing with an electrode rod. It can be inserted into the insertion hole 3.

The optical ferrule 1 of the third embodiment
Then, a single mode optical fiber was inserted and fixed in the same manner as in the first embodiment, and the connection loss between the single mode optical fibers was measured.
It was 2 dB, and the connection loss fluctuation range at −40 ° C. to 80 ° C. was 0.2 dB, which was the same value as in the first embodiment, and a value that was practically acceptable.

FIG. 3 is a perspective view showing a fourth embodiment of the optical ferrule according to the present invention. The fourth embodiment is substantially the same as the first embodiment, and the fourth embodiment is different from the first embodiment in that the optical ferrule 1 has a current The electrode 7 used for flowing the fluid is insert-molded. The electrodes 7 are provided so as to sandwich the formation region of the optical fiber insertion hole 3 from both sides.

The fourth embodiment is constructed as described above. The fourth embodiment is manufactured in substantially the same manner as the first and third embodiments. In the embodiment, the electrode 7 is manufactured by insert molding at the time of the injection molding. When the optical fiber is inserted and fixed in the optical ferrule 1 of the fourth embodiment, the electrode 7 is energized to heat the optical ferrule 1 in the same manner as in the third embodiment, and the optical fiber insertion hole is formed. The optical fiber is inserted into the optical fiber insertion hole 3 by enlarging the optical fiber 3 and then returning to room temperature.

The fourth embodiment can also provide the same effects as those of the first to third embodiments. Further, according to the fourth embodiment, since the electrode 7 is manufactured by insert molding, it is possible to more easily heat the optical ferrule 1 using the electrode 7,
The optical fiber can be more easily fixed to the optical fiber insertion hole 3.

Incidentally, the optical ferrule 1 of the fourth embodiment example
Then, a single mode optical fiber was inserted and fixed in the same manner as in the first embodiment, and the connection loss between the single mode optical fibers was measured.
It was 2 dB, and the connection loss fluctuation range at −40 ° C. to 80 ° C. was 0.2 dB, which was the same value as in the first embodiment, and a value that was practically acceptable.

FIGS. 4 (a) and 4 (b) show an optical ferrule according to a fifth embodiment of the present invention in an exploded state, and FIG. 4 (c) shows this optical ferrule. An external perspective view is shown. Optical ferrule 1 of the fifth embodiment
Covers the outer periphery of the optical ferrule (optical ferrule main body 10) as shown in FIG.
Is provided with an exterior member for preventing the expansion of the optical ferrule main body 10 within the use temperature range.

As shown in (b) of FIG.
An upper package 12 and a lower package 13 are provided, and the upper package 12 and the lower package 13
The optical ferrule body 10 is formed of the same material as that of the optical ferrule body 10, so that the linear expansion coefficients of these packages 12 and 13 have the same value as the linear expansion coefficient of the optical ferrule body 10.

The upper package 12 and the lower package 13 are provided with ferrule storage portions 14 and 15 and projections 18 and 19 for fixing the optical fiber coating portion, respectively. Fitting protrusions 20 are formed on both sides of the upper package 12.
Are formed to protrude inward. Meanwhile, lower package 1
3 are formed on both sides thereof with fitting recesses 21 to be fitted to the fitting projections 20 of the upper package 12, and the locking claw of the upper package 12 is locked in the fitting recess 20. A claw locking recess 17 is formed.

In the optical ferrule 1 of the fifth embodiment, an optical ferrule body 10 as shown in FIG. 4A is manufactured in the same manner as in the first embodiment, and After the optical fiber is inserted and fixed in the same manner as in the first embodiment, the optical ferrule body is inserted into the ferrule receiving portions 14 and 15 between the lower package 13 and the upper package 12 as shown in FIG. Containing ten,
As shown in (c) of FIG.
0 is fitted in the fitting concave portion 21 of the lower package 13 to manufacture.

The fifth embodiment can also provide the same effects as those of the first embodiment. In the fifth embodiment, the upper package 12 and the lower package 13
Is provided to form the optical ferrule 1, the optical fiber can be more securely fixed to the optical fiber insertion hole 3, and the mechanical strength can be increased. Actually, in the optical ferrule 1 of the fifth embodiment, the optical fibers protruding from one end of the upper package 12 and the lower package 13 are fixed, and the optical fibers protruding from the other end are linearly moved by 50N. Then, the connection loss between the optical fibers was measured. As a result, the connection loss between the optical fibers did not increase as compared to before the pulling.

FIG. 5 shows an optical ferrule 6 according to the present invention.
An optical switch formed using an example embodiment is shown. The sixth embodiment is substantially the same as the first embodiment, and the present embodiment is different from the first embodiment in that the number of formed optical fiber insertion holes 3 is different from that of the first embodiment. Further, the number of optical fiber insertion grooves 2 formed on both sides thereof is set to be equal to the number of fixed optical fibers 8 provided in the optical switch.

The present embodiment is configured as described above. In the optical switch shown in FIG. 5, a plurality of fixed-side optical fibers 8 pulled out from the optical fiber ribbon 29 and a moving-side optical fiber 8 are provided. The connection with the fiber 9 is made switchable, but the fixed optical fiber is inserted into the optical fiber insertion hole 3 from the optical fiber insertion part 5 on one side of the optical ferrule 1 as in the first embodiment. The optical fiber 9 on the moving side is inserted into the optical fiber insertion hole 3 from the optical fiber insertion portion 5 on the other side of the optical ferrule 1, and the optical fiber 8 and the optical fiber 9 are inserted in the optical fiber insertion hole 3. Optically connected by physical contact.

When switching the connection between the optical fiber 8 and the optical fiber 9 in this optical switch, the optical ferrule 1 is heated to a switching temperature or higher, and the optical fiber insertion hole 3 is enlarged and the optical fiber insertion hole 3 is enlarged. After pulling out the optical fiber 9 from the optical fiber insertion hole 3 and inserting the optical fiber 9 into the different optical fiber insertion hole 3, the ferrule 1 is cooled to around room temperature, and the optical fiber 9 is fixed to the optical fiber insertion hole 3 again. Perform the operation. When the optical fiber 9 is inserted into or removed from the optical fiber insertion hole 3, the time for heating the optical ferrule 1 and the time for cooling it are both one.
Minutes.

The sixth embodiment can also provide the same effects as the first embodiment, whereby an optical switch as shown in FIG. 5 can be formed using the optical ferrule 1 of the sixth embodiment. When formed, the connection switching between the optical fiber 8 and the optical fiber 9 can be performed very easily, and the optical fiber 8 and the optical fiber 9 can be switched freely with very low connection loss. An optical switch can be formed.

Next, a description will be given of a seventh embodiment of the optical ferrule according to the present invention. The structure of the optical ferrule of the present embodiment is substantially the same as that of the conventional optical ferrule 1 shown in FIG. 7. The optical fiber is formed of a composite material having substantially the same properties as those of the first to fifth embodiments, and the inner diameter of the optical fiber insertion hole 3 is set to 124 μm, as in the first to fifth embodiments. That is, the optical fiber is formed smaller than the outer diameter of the optical fiber inserted into the insertion hole 3.

The optical ferrule 1 of the seventh embodiment
Is formed by blending 200 parts by weight of thermal black with 100 parts by weight of polyphenylene sulfide resin. The composite material has a volume resistivity at room temperature of 10 Ω · cm and a switching temperature. Is about 150 ° C.

The optical ferrule 1 of the seventh embodiment is manufactured in substantially the same manner as in the first embodiment.
In the embodiment, when the optical ferrule 1 is injection-molded, a mold different from that of the first embodiment is used, and the outer diameter is 128 μm.
m.

The optical ferrule 1 of the seventh embodiment is
When the optical fiber is inserted and fixed in the optical ferrule 1, the energizing jig as shown in FIG. 6 is attached to the optical ferrule 1 and the gate of the optical ferrule 1 (immediately after being removed from the mold), as in the first embodiment. The electrode is brought into close contact with the surface of the optical ferrule 1 that is exposed when the optical ferrule 1 is taken from the state where the runner is attached, and is formed on both sides of the flange portion 37 of the optical ferrule 1). When the self-temperature control was started at about 150 ° C., the coating on the tip side of the optical fiber ribbon was removed, and the optical fiber whose tip was cut with a precision cutter was used as an optical ferrule. 1
In the optical fiber insertion hole 3.

Thereafter, the power supply was stopped and the temperature was allowed to stand near room temperature. When the optical fiber insertion hole 3 was reduced and the optical fiber was fixed in the optical fiber insertion hole 3, the connection of the optical ferrule 1 was performed using a polishing jig. The end face 27 and the optical fiber connection end face were polished together to produce an optical connector. In addition, the heating time and the cooling time of the optical ferrule 1 at the time of manufacturing the optical connector were both 1 minute.

According to the seventh embodiment, as described above, the heating and cooling of the optical ferrule 1 can be performed very easily and without using the adhesive necessary for the conventional optical connector fabrication. It is possible to securely fix the optical fiber to the optical fiber insertion hole 3, whereby the optical fiber ribbon can be easily and quickly connected to the optical ferrule 1.
And it can be fixed reliably. Therefore, the work can be performed with good workability even when connecting work on an elevated pole on a telephone pole or the like. For example, the adhesive may protrude from the optical fiber insertion hole 3 of the optical ferrule 1 to the connection end face side. Therefore, the connection end face and the optical fiber can be easily polished.

Also, in the seventh embodiment, similarly to the first to sixth embodiments, the optical fiber is fixed to the optical ferrule 1 so that the optical fiber can be fixed to the optical ferrule 1 reliably. When the formed optical connectors are connected via the positioning pins 26, the optical fibers can be connected with low connection loss.

Incidentally, the optical ferrule 1 of the seventh embodiment is explained.
Are prepared, and a single mode optical fiber is inserted and fixed in these optical ferrules 1 as in the first embodiment, and the optical ferrules 1 are connected to each other via pins 26 to connect the single mode optical fibers to each other. When the splice loss was measured, the average splice loss was about 0.35 dB,
The connection loss fluctuation width at 80 ° C. is within 0.2 dB,
The value was no problem for practical use.

Note that the present invention is not limited to the above-described embodiment, but can adopt various embodiments. For example, in the first and third to seventh embodiments, the switching temperature of the composite material forming the optical ferrule 1 is set to about 150.
° C and the switching temperature of the composite material forming the optical ferrule 1 is about 118 ° C in the second embodiment, but the switching temperature of the composite material forming the optical ferrule 1 is not particularly limited. The temperature is set to an appropriate temperature exceeding the upper limit of the operating temperature range of the optical ferrule 1.

The currently used optical ferrule 1
Is often in the range of about -40 ° C to 80 ° C. Therefore, when the present invention is applied to such an optical ferrule 1, the switching temperature may be set to, for example, 100 ° C or higher.

As described above, if the switching temperature of the composite material forming the optical ferrule 1 is set to a temperature exceeding the upper limit of the operating temperature range of the optical ferrule 1, the diameter of the optical fiber insertion hole 3 which occurs near the switching temperature is set. Does not occur within the operating temperature range of the optical ferrule 1, the optical fiber is inserted into the optical fiber insertion hole 3 when the optical fiber is used. 3 can be reliably prevented, and the optical connection between the optical fibers can be maintained in a low connection loss state for a long time.

Further, the composite material forming the optical ferrule 1 is not limited to the material forming the optical ferrule 1 in each of the above embodiments, and the crystallinity is at least 10%.
% Of a crystalline resin and a conductive filler at a volume resistivity of 50 Ω · cm or less at room temperature, and has a positive temperature coefficient characteristic that the volume resistivity increases as the temperature increases, and an optical ferrule. Has a switching temperature exceeding the upper limit of the operating temperature range, and has a volume resistivity of at least 100 Ω · c above the switching temperature.
m or more.

Specifically, polyethylene resin, polypropylene resin, polyphenylene sulfide resin, polyarylate resin, syndiotactic polystyrene resin and the like are suitable as the crystalline resin. In addition, as the conductive filler, thermal black, furnace black, carbon black such as acetylene black,
Metal powders such as copper powder and nickel powder are exemplified. Further, if necessary, a filler such as silica, titanium oxide, calcium carbonate, alumina, clay, or glass fiber, or a flame retardant may be added to form the optical ferrule 1.

By appropriately setting the mixing ratio of the crystalline resin and the conductive filler, the volume resistivity at room temperature is 50 Ω · cm or less, and the positive temperature at which the volume resistivity increases as the temperature increases. A composite material having a coefficient characteristic and having a switching temperature exceeding the upper limit of the operating temperature range of the optical ferrule, and further having a volume resistivity of at least 100 Ω · cm or higher at the switching temperature or higher. By determining the composition of the optical ferrule 1, the optical ferrule 1 having the same effects as those of the above embodiments can be formed. The mixing ratio of the resin and the conductive filler depends on the type of the resin and the conductive filler. For example, the conductive filler is desirably 10 to 300 parts by weight with respect to 100 parts by weight of the resin. .

Further, in each of the above embodiments, the material for forming the optical ferrule 1 is cross-linked by electron beam after injection molding of the optical ferrule 1, but the cross-linking means is not particularly limited. Chemical cross-linking by addition (a cross-linking agent is added at the time of material kneading, and after molding, the optical ferrule 1
The material for forming the optical ferrule 1 may be cross-linked by a method of chemically cross-linking by heating the material.
In addition, such a cross-link is not always applied to the forming material of the optical ferrule 1, and the cross-linking is performed as needed. However, in consideration of properties such as the mechanical strength of the optical ferrule 1, It is desirable to crosslink the forming material of the optical ferrule 1.

Further, in the seventh embodiment, an electrode is brought into close contact between the gates of the optical ferrule 1 and
To heat the optical ferrule 1, the pin insertion hole 25 may be used as an electrode insertion hole, an electrode may be inserted into the pin insertion hole 25, and a current may be applied to this electrode to heat the optical ferrule 1. As in the fourth embodiment, the electrode 7 may be insert-molded to form the optical ferrule 1, and a current may be applied to the electrode 7 to heat the optical ferrule 1.

Further, in each of the above embodiments, the optical ferrule 1 is energized to generate heat by itself, and the optical fiber is inserted into the optical fiber insertion hole 3 in a state where the optical ferrule 1 is self-temperature controlled at the switching temperature. However, by heating the optical ferrule 1 in, for example, a furnace, the optical ferrule 1 is raised to a switching temperature, and the inner diameter of the optical fiber insertion hole 3 is changed to the outer diameter of the optical fiber inserted into the optical fiber insertion hole 3. In the above enlarged state, the optical fiber is inserted into the optical fiber insertion hole 3, and then the optical ferrule 1 is cooled to reduce the inner diameter of the optical fiber insertion hole 3 to a diameter smaller than the outer diameter of the optical fiber, The optical fiber may be fixed to the optical fiber insertion hole 3.

However, in this case, since heating means such as a furnace for heating the optical ferrule 1 and temperature control means are required, the optical fiber is inserted into the optical fiber insertion hole 3 of the optical ferrule 1. Since the device for inserting and fixing becomes large-scale and the workability decreases, the optical ferrule 1 is formed of a conductive material and the optical fiber insertion hole of the optical ferrule 1 is provided as in the above embodiments. It is desirable to arrange electrodes on both sides of the formation region of No. 3 and to heat the optical ferrule 1 by supplying a current to the electrodes.

Further, in the fifth embodiment, the outer package covering the optical ferrule main body 10 of the optical ferrule 1 is composed of the upper package 12 and the lower package 13. However, the configuration of the outer package is not particularly limited. The optical ferrule (optical ferrule main body 10) may be set as appropriate and may cover the outer periphery of the optical ferrule (optical ferrule main body 10) and prevent expansion of the optical ferrule main body 10 within the operating temperature range of the optical ferrule 1.

The material of such an exterior member may be the same as that of the optical ferrule body 10 as in the fifth embodiment, but may be a different material. Any material having a linear expansion coefficient equal to or less than the linear expansion coefficient of the optical ferrule may be used. For example, plastic, ceramic, metal or the like can be used. However, in consideration of cost and workability, plastic is desirable. As the type of plastic (resin), polyethylene resin,
Thermoplastic resins such as polypropylene resin, polyphenylene sulfide resin, polyarylate resin and syndiotactic polystyrene resin, and thermosetting resins such as phenol resin and epoxy resin.

Further, in order to reduce the linear expansion coefficient of the exterior member, silica, glass fiber, titanium oxide,
Calcium carbonate, alumina, clay and the like may be blended, and if necessary, additives such as a flame retardant may be blended in the exterior member forming material.

Further, in the first to sixth embodiments, the optical fiber insertion groove 2 communicating with the optical fiber insertion hole 3 is formed in the optical fiber insertion portion 5, but the optical fiber insertion groove 2 is not necessarily formed. Not necessarily. However, if the optical fiber insertion groove 2 is formed in the optical fiber insertion portion 5, the operation of introducing the optical fiber into the optical fiber insertion hole 3 can be performed more easily and accurately. 5 is preferably provided with an optical fiber insertion groove 2.

Further, the structure of the optical ferrule of the present invention is as follows:
The structure is not limited to the structure shown in each of the above embodiments, and one or more optical fiber insertion holes are formed, and the inner diameter of the optical fiber insertion hole at room temperature is inserted into the optical fiber insertion hole. Is formed so as to be smaller than the outer diameter of the resin and has a crystallinity of at least 10% or more and a crystalline resin and a conductive filler, and has a volume resistivity of 50 Ω · cm or less at room temperature. It has a positive temperature coefficient characteristic in which the volume resistivity increases as the temperature increases, and has a switching temperature that exceeds the upper limit of the operating temperature range of the optical ferrule, and furthermore, the volume resistivity exceeds the switching temperature. May be formed of a composite material having at least 100 Ω · cm or more.

[0092]

According to the present invention, the optical ferrule is formed of a composite material having a crystalline resin having a crystallinity of at least 10% or more and a conductive filler, and the composite material has a volume resistivity of room temperature. Is less than 50Ωcm,
When a voltage is applied to the optical ferrule to cause a current to flow, the optical ferrule generates heat, and the optical ferrule has a positive temperature coefficient characteristic (P) in which the volume resistivity increases as the temperature increases.
(TC characteristic), and the volume resistivity at the switching temperature or higher is at least 100 Ω · cm or more. Therefore, the resistance rapidly increases at the switching temperature near the melting point of the material, and the temperature does not further rise. The self-temperature control function can be reliably exhibited.

The optical ferrule of the present invention has at least one optical fiber insertion hole for inserting and fixing an optical fiber. The inner diameter of the optical fiber insertion hole at room temperature is inserted into the optical fiber insertion hole. Although the diameter of the optical fiber is smaller than the outer diameter of the optical fiber, the volume expansion (thermal expansion) at the switching temperature allows the optical fiber insertion hole of the optical ferrule to be enlarged. Then, with the inner diameter of the optical fiber insertion hole enlarged beyond the outer diameter of the optical fiber inserted into the optical fiber insertion hole, insert the optical fiber into the optical fiber insertion hole, and then return the optical ferrule to room temperature. The volume of the optical ferrule is contracted to reduce the inner diameter of the optical fiber insertion hole to a diameter smaller than the outer diameter of the optical fiber, making it very easy and reliable. , It is possible to fix the optical fibers into the optical fiber insertion hole.

Therefore, by utilizing the self-temperature control function of the optical ferrule, as described above, a separate heating device, a temperature control circuit, a sensor, and the like are not required, and the workability of the optical ferrule is improved. An optical fiber can be inserted and fixed in the fiber insertion hole.

Since the optical ferrule of the present invention has a switching temperature at a temperature exceeding the upper limit of the operating temperature range of the optical ferrule, the volume expansion phenomenon caused by the self-temperature control function causes the optical ferrule to operate within the operating temperature range of the optical ferrule. Since it occurs at a temperature exceeding the upper limit, the phenomenon that the optical fiber insertion hole expands as described above at the upper limit of the operating temperature range of the optical ferrule does not occur, and the optical fiber is securely fixed to the optical fiber insertion hole. State can be maintained.

Further, since the operating temperature of the currently used optical ferrule is -40 ° C. to 80 ° C., according to the second aspect of the optical ferrule in which the switching temperature is set to 100 ° C. or higher, The volume expansion phenomenon due to the self-temperature control function does not occur in the same operating temperature environment as the currently used optical ferrule, and the state in which the optical fiber is securely fixed in the optical fiber insertion hole can be maintained. it can.

Further, as described above, the volume shrinkage of the optical ferrule which occurs when the optical ferrule is heated to a switching temperature or more and then returned to room temperature also occurs in the longitudinal direction of the optical fiber insertion hole. Are formed by through holes, and optical fiber insertion portions for inserting optical fibers into the optical fiber insertion holes are formed on both sides sandwiching the formation region of the optical fiber insertion hole in the longitudinal direction of the optical fiber insertion hole, respectively. The third invention of an optical ferrule having a configuration in which an optical fiber is inserted from both sides of an optical fiber insertion hole through an optical fiber insertion portion of the present invention is a physical ferrule between optical fibers inserted from both directions of an optical fiber insertion hole. It is possible to increase the contact force, and it is possible to reduce the connection loss between the optical fibers inserted and fixed.

According to the third aspect of the optical ferrule, the optical fiber is inserted into the optical fiber insertion hole from both sides of the optical fiber insertion hole via the optical fiber insertion portion. Unlike the mechanical splice type optical ferrule described above, the optical ferrule is formed by providing many components such as an upper plate member, a lower plate member, and a fixing member for fixing these members.
As an optical ferrule formed by two parts, an optical fiber inserted from both sides of the optical ferrule can be optically connected, so that optical connection of the optical fiber can be performed with very good workability. .

Further, in addition to the configuration of the third aspect of the optical ferrule, the optical fiber insertion portion communicates with the optical fiber insertion hole and inserts the optical fiber inserted into the optical fiber insertion hole into the optical fiber insertion hole. According to the fourth aspect of the optical ferrule having the optical fiber insertion groove formed therein, the optical fiber is guided into the optical fiber insertion hole by guiding the optical fiber into the optical fiber insertion hole. The work of inserting the optical fiber into the optical fiber insertion hole can be further improved.

Further, the optical ferrule is formed with one or more pairs of pin insertion holes for inserting positioning pins for connecting the optical ferrule to an optical component on the other side of connection.
An optical fiber insertion hole is formed at a distance from the pin insertion hole so that the optical fiber insertion hole is sandwiched between the pin insertion holes. One end of the optical fiber insertion hole is connected to an optical ferrule. According to the fifth aspect of the optical ferrule exposed on the end face side, the optical fiber is connected to the conventional optical ferrule having the same structure without using an adhesive necessary for fixing the optical fiber. Since the optical fiber can be inserted and fixed in the fiber insertion hole, the optical fiber can be fixed to the optical fiber insertion hole in a short time and with good workability without requiring the time required for curing the adhesive.

Further, according to the sixth aspect of the optical ferrule having an electrode insertion hole for inserting an electrode used to pass a current through the optical ferrule, the electrode is inserted into the electrode insertion hole. Since the optical ferrule can be easily energized and heated, the operation of inserting the optical fiber into the optical fiber insertion hole of the optical ferrule can be performed more easily.

Furthermore, according to the seventh aspect of the optical ferrule in which an electrode used for flowing a current through the optical ferrule is insert-molded, the optical ferrule can be easily energized and heated using the electrode. Therefore, the operation of inserting an optical fiber into the optical fiber insertion hole of the optical ferrule can be performed more easily, as in the sixth aspect of the present invention.

Further, the optical ferrule is provided with an exterior member that covers the outer periphery of the optical ferrule and prevents expansion of the optical ferrule within the operating temperature range of the optical ferrule, and has a linear expansion coefficient of the optical ferrule. According to the eighth aspect of the optical ferrule having a value equal to or less than the linear expansion coefficient of the optical ferrule, the optical fiber can be more securely fixed to the optical ferrule more securely. Can increase the mechanical strength.

Further, according to the first aspect of the method for fixing an optical fiber to an optical ferrule, the optical ferrule is heated to allow the optical fiber to pass through the optical fiber insertion hole, and thereafter, the optical ferrule is simply cooled. The optical fiber can be very easily and reliably fixed to the optical fiber insertion hole.

Further, according to the second aspect of the method of fixing an optical fiber to an optical ferrule, electrodes are provided on both sides of an optical fiber insertion hole forming region of an optical ferrule formed of a conductive material, By passing a current through this electrode, the optical ferrule can be easily heated. If the optical ferrule is the optical ferrule of the present invention described above, the self-temperature control function of the optical ferrule is activated by heating by energization, and the optical fiber is very easily and securely fixed to the optical fiber insertion hole. You can
Since the power supply of the device that heats the optical ferrule by energization can be adequately controlled by a dry cell, the energizing device can be made small, and the workability of fixing the optical fiber to the optical ferrule is very good. It can be.

[Brief description of the drawings]

FIG. 1 is a main part configuration diagram showing a first embodiment and a second embodiment of an optical ferrule according to the present invention.

FIG. 2 is a main part configuration diagram showing a third embodiment of the optical ferrule according to the present invention.

FIG. 3 is a main part configuration diagram showing a fourth embodiment of the optical ferrule according to the present invention.

FIG. 4 is a main part configuration diagram showing a fifth embodiment of the optical ferrule according to the present invention.

FIG. 5 is a main part configuration diagram showing a state in which an optical switch according to a sixth embodiment of the present invention is incorporated in an optical switch.

FIG. 6 is a main part configuration diagram showing an example of an energizing jig used to fix an optical fiber to the optical ferrule according to the present invention.

FIG. 7 is an explanatory view showing a connection method of two optical connectors formed using an optical connector type optical ferrule in a state where positioning pins are fitted to one of the optical connectors.

FIG. 8 is an explanatory view showing a conventional mechanical splice type optical ferrule.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical ferrule 2 Optical fiber insertion groove 3 Optical fiber insertion hole 4 Hole forming part 5 Optical fiber insertion part 6 Electrode insertion hole 7 Electrode 8, 9 Optical fiber 10 Optical ferrule main body 11 Upper package 12 Lower package 25 Pin insertion hole

Claims (10)

[Claims] 1. An optical ferrule having one or more optical fiber insertion holes for inserting and fixing an optical fiber, wherein the optical ferrule comprises a crystalline resin having a crystallinity of at least 10% and a conductive filler. The composite material has a positive temperature coefficient characteristic in which the volume resistivity increases as the temperature increases at a specific temperature of 50 Ω · cm or less at room temperature, and the operating temperature of the optical ferrule. It has a switching temperature at a temperature exceeding the upper limit of the range, and further has a volume resistivity at or above the switching temperature of at least 100 Ωcm, and the inside diameter of the optical fiber insertion hole at room temperature is equal to the optical fiber insertion hole. An optical ferrule formed to be smaller than an outer diameter of an optical fiber to be inserted. 2. The optical ferrule according to claim 1, wherein the switching temperature is 100 ° C. or higher. 3. An optical fiber insertion hole is formed by a through hole, and an optical fiber is inserted into the optical fiber insertion hole on both sides of a region where the optical fiber insertion hole is formed in the longitudinal direction of the optical fiber insertion hole. An optical fiber insertion portion for forming an optical fiber is formed, and an optical fiber is inserted from both sides of the optical fiber insertion hole through the optical fiber insertion portion. 2. The optical ferrule according to 2. 4. An optical fiber insertion portion, wherein an optical fiber insertion groove communicating with the optical fiber insertion hole and guiding an optical fiber inserted into the optical fiber insertion hole to the optical fiber insertion hole is formed. The optical ferrule according to claim 3, wherein 5. The optical ferrule is formed with one or more pairs of pin insertion holes for inserting pins for positioning when connecting the optical ferrule to an optical component on the other side of connection. An optical fiber insertion hole is formed through the optical fiber insertion hole is sandwiched by the pin insertion hole, one end of the optical fiber insertion hole is exposed to the connection end face side of the optical ferrule. The optical ferrule according to claim 1 or 2, wherein 6. The light according to claim 1, wherein an electrode insertion hole for inserting an electrode used for flowing a current through the optical ferrule is formed. Ferrule. 7. The optical ferrule according to claim 1, wherein an electrode used for flowing a current through the optical ferrule is insert-molded. 8. An optical ferrule is provided with an exterior member which covers an outer periphery of the optical ferrule and prevents expansion of the optical ferrule within a use temperature range of the optical ferrule, and has a linear expansion coefficient of the optical ferrule. The optical ferrule according to any one of claims 1 to 7, wherein the optical ferrule has a value equal to or less than a linear expansion coefficient. 9. An optical fiber inserted into an optical fiber insertion hole in a state in which the optical ferrule is heated to expand the inner diameter of the optical fiber insertion hole of the optical ferrule to be larger than the outer diameter of the optical fiber inserted into the optical fiber insertion hole. The optical fiber is fixed to the optical fiber insertion hole by reducing the inner diameter of the optical fiber insertion hole to a diameter smaller than the outer diameter of the optical fiber by cooling the optical ferrule after that. An optical fiber fixing method to an optical ferrule. 10. The optical ferrule is formed of a conductive material. Electrodes are disposed on both sides of the optical ferrule with the optical fiber insertion hole forming region interposed therebetween, and a current is caused to flow through the electrode to form the optical ferrule. The method for fixing an optical fiber to an optical ferrule according to claim 9, wherein the optical fiber is heated.