JP2023030813A - Optical combiner manufacturing method - Google Patents

Abstract

To provide an optical combiner manufacturing method with which it is possible to easily suppress a decrease in joint strength and an increase in connection losses when joining an input optical fiber and an output optical fiber together.SOLUTION: The present method includes: a fiber bundle formation step in which a plurality of input optical fibers 10 having a termination end 14 where a clad 12 is exposed to the outside are bundled so as to form a fiber bundle 20; an adhesion part formation step in which a reversible adhesive 40 having the nature of being reversibly hardened and softened is added to the termination end 14 of the fiber bundle 20 so as to form an adhesion part 50 where the input optical fiber 20 is bonded; a cutting step in which the adhesion part 50 is cut at a prescribed cut position so as to remove a tip 50A of the adhesion part 50; a first adhesive softening step in which the reversible adhesive 40 at a tip 51 of a remaining adhesion part 50B is softened; and a fiber joining step in which a joint end 70 where the clad 12 of the input optical fiber 20 is exposed and an end 85 of an output optical fiber 80 are joined to each other after the first adhesive softening step.SELECTED DRAWING: Figure 1E

Description

The present invention relates to a method of manufacturing an optical combiner, and more particularly to a method of manufacturing an optical combiner in which a plurality of input optical fibers and one output optical fiber are connected.

With the recent increase in the output of laser devices, input optical fibers connected to a plurality of light sources are multiplexed by an optical combiner and output from a single output optical fiber. Conventionally, such an optical combiner has been produced as follows. First, the coating is removed from one end of a plurality of input optical fibers, and these input optical fibers are bundled and inserted into a half-structured ferrule. Then, the end faces of these input optical fibers are brought into contact with the flat surface of the adjustment tool, adjusted so that the end faces of all the input optical fibers are flush with each other, and fixed with a clamp. The input optical fiber and the output optical fiber are set in the fusion splicer so that the end face of the input optical fiber and the end face of the output optical fiber face each other in this state. A fusion splicer heats the connecting portion between the input optical fiber and the output optical fiber to fusion splice the input optical fiber and the output optical fiber. Finally, the ferrule is disassembled and removed from the input optical fiber to complete the optical combiner (see, for example, paragraph [0049] of Patent Document 1).

When manufacturing an optical combiner, if the end faces of multiple input optical fibers are uneven, the optical loss in the optical combiner increases and the intensity of the light combined by the optical combiner decreases. The fiber end faces should be as flush as possible. However, the task of bringing the end faces of a plurality of input optical fibers into flush contact with the plane of the adjustment tool as in the above-described conventional method requires skill and experience. Moreover, in the conventional method, when the end face of the input optical fiber is brought into contact with the flat surface of the adjustment tool, the tip of the input optical fiber may be chipped or damaged. It is conceivable that the damage causes a decrease in joint strength and an increase in connection loss when the input optical fiber and the output optical fiber are joined.

WO2011/052373

SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the prior art, and is capable of easily suppressing a decrease in joint strength and an increase in connection loss when an input optical fiber and an output optical fiber are joined. It aims at providing the manufacturing method of an optical combiner.

According to one aspect of the present invention, there is provided a method for manufacturing an optical combiner that can easily suppress a decrease in joint strength and an increase in connection loss when an input optical fiber and an output optical fiber are joined. This method includes a fiber bundle forming step of bundling a plurality of input optical fibers having terminal ends with exposed claddings to form a fiber bundle, and the terminal end of the fiber bundle formed by the fiber bundle forming step. a reversible adhesive having a property of reversibly hardening and softening is applied to at least a part of the bonding portion to form a bonding portion in which the plurality of input optical fibers are bonded to each other by the reversible adhesive. a forming step; a cutting step of cutting the adhesive portion formed by the adhesive portion forming step at a predetermined cutting position in the longitudinal direction to remove a tip side of the adhesive portion; and the adhesive portion remaining after the cutting step. a first adhesive softening step of softening the reversible adhesive at the distal end portion of the first adhesive softening step; and a spliced end portion where the cladding of the plurality of input optical fibers is exposed and output light after the first adhesive softening step and a fiber splicing step of splicing the ends of the fibers together.

FIG. 1A is a schematic diagram for explaining the method for manufacturing an optical combiner according to the first embodiment of the present invention. FIG. 1B is a schematic diagram for explaining the method of manufacturing the optical combiner according to the first embodiment of the present invention. FIG. 1C is a schematic diagram for explaining the method of manufacturing the optical combiner according to the first embodiment of the present invention. FIG. 1D is a schematic diagram for explaining the method of manufacturing the optical combiner according to the first embodiment of the present invention. FIG. 1E is a schematic diagram for explaining the manufacturing method of the optical combiner according to the first embodiment of the present invention. FIG. 1F is a schematic diagram for explaining the manufacturing method of the optical combiner according to the first embodiment of the present invention. FIG. 1G is a schematic diagram for explaining the method of manufacturing the optical combiner according to the first embodiment of the present invention. FIG. 1H is a schematic diagram for explaining the method of manufacturing the optical combiner according to the first embodiment of the present invention. FIG. 1I is a schematic diagram for explaining the manufacturing method of the optical combiner according to the first embodiment of the present invention. FIG. 1J is a schematic diagram for explaining the method of manufacturing the optical combiner according to the first embodiment of the present invention. FIG. 2A is a schematic diagram for explaining a method for manufacturing an optical combiner according to the second embodiment of the present invention. FIG. 2B is a schematic diagram for explaining the method of manufacturing the optical combiner according to the second embodiment of the present invention. FIG. 3 is a schematic diagram for explaining a method for manufacturing an optical combiner according to the third embodiment of the present invention.

Hereinafter, an embodiment of a method for manufacturing an optical combiner according to the present invention will be described in detail with reference to FIGS. 1A to 3. FIG. In FIGS. 1A to 3, the same or corresponding components are given the same reference numerals, and overlapping descriptions are omitted. In addition, in FIGS. 1A to 3, the scale and dimensions of each component may be exaggerated, and some components may be omitted. In the following description, unless otherwise specified, terms such as "first" and "second" are used only to distinguish components from each other and indicate a particular rank or order. not a thing

A method for manufacturing an optical combiner according to a first embodiment of the present invention will be described with reference to FIGS. 1A to 1J. First, an input optical fiber 10 as shown in FIG. 1A is prepared. This input optical fiber 10 includes a core 11 , a clad 12 surrounding the core 11 , and a coating 13 surrounding the clad 12 . The clad 12 has a lower refractive index than the core 11 and an optical waveguide is formed inside the core 11 . The coating 13 is removed at the terminal end 14 of the input optical fiber 10, and the clad 12 is exposed to the outside.

A plurality of such input optical fibers 10 (seven in this embodiment) are prepared and bundled to form a fiber bundle 20 as shown in FIG. 1B (fiber bundle forming step). At this time, the end faces of these input optical fibers 10 need not be aligned in the longitudinal direction.

Next, a reversible adhesive is applied to a part of the terminal portion 14 of the fiber bundle 20 to form a bonded portion in which the plurality of input optical fibers 10 are bonded together by the reversible adhesive (bonded portion forming step). ). This reversible adhesive is an adhesive that has the property of reversibly hardening and softening depending on specific conditions. For example, as such a reversible adhesive, an adhesive that has the property of reversibly curing and softening due to changes in temperature (heating), irradiation of light (visible light and ultraviolet rays), irradiation of electron beams, changes in humidity, etc. are known, and other adhesives that are reversibly hardened and softened by changes in pH, reaction with specific chemical substances, current application, etc. are also conceivable.

In this embodiment, the bonding portion forming step is performed as follows. First, as shown in FIG. 1C, the tip of the terminal portion 14 of the fiber bundle 20 is immersed in the liquid reversible adhesive 40 held inside the container 30 (fiber immersion step). At this time, the reversible adhesive 40 permeates between the clads 12 at the end portion 14 of the fiber bundle 20 , so that the reversible adhesive 40 can be evenly adhered to the end portion 14 of the fiber bundle 20 . Also, the cladding 12 of the terminal end 14 of the fiber bundle 20 is centered closely together by the surface tension of the reversible adhesive 40 . In this embodiment, as the reversible adhesive 40, a photoresponsive adhesive having a property of being cured by irradiation of light of a predetermined wavelength (curing wavelength) and softened by irradiation of light of a predetermined wavelength (softening wavelength) is used. use.

When the fiber bundle 20 is pulled up from the reversible adhesive 40 in the container 30, as shown in FIG. becomes. Then, the photoresponsive adhesive 40 is cured by irradiating light of a curing wavelength (hereinafter referred to as curing light) to the photoresponsive adhesive 40 (curing light irradiation step). As a result, a bonding portion 50 is formed at the tip of the terminal portion 14 of the fiber bundle 20 , in which the plurality of input optical fibers 10 are bonded together with the photoresponsive adhesive 40 .

After forming the bonded portion 50 at the tip of the terminal portion 14 of the fiber bundle 20 in this way, as shown in FIG. The side portion 50A is removed (cutting step). At this time, since the terminal end portions 14 of the input optical fibers 10 can be cut in the same plane, the end faces of the terminal end portions 14 of the plurality of input optical fibers 10 can be easily made flush even without skill or experience. can be aligned.

After this cutting step, the photoresponsive adhesive 40 at the tip of the remaining adhesive portion 50B is softened (first adhesive softening step). In the first adhesive softening step of the present embodiment, as shown in FIG. 1F, a light shielding member 60 extending in the longitudinal direction is arranged along the fiber bundle 20, and the tip portion 51 of the adhesive portion 50B is softened by the light shielding member 60. The portion 52 other than the above is covered (light shielding member placement step). In this state, by irradiating the adhesive portion 50B with light of a softening wavelength (hereinafter referred to as softening light) through the light shielding member 60, the portion of the photoresponsive adhesive 40 irradiated with the softening light is softened (first softening light irradiation step). At this time, since only the tip portion 51 of the adhesive portion 50B is irradiated with the softening light by the light shielding member 60, only the photoresponsive adhesive 40 at the tip portion 51 of the adhesive portion 50B is softened. In the illustrated example, the entire portion 52 of the bonding portion 50B other than the tip portion 51 is covered with the light shielding member 60. You can do it.

The softened photoresponsive adhesive 40 is then removed from the fiber bundle 20 to form a splice end 70 exposing the cladding 12 of the input optical fiber 10 (first adhesive removal step). In this first adhesive removing step, for example, the adhesive portion 50B may be immersed in a solvent to remove the photoresponsive adhesive 40 from the tip portion 51, and then the solvent may be washed away. Alternatively, the photoresponsive adhesive 40 on the tip portion 51 may be removed by dry cleaning the adhesive portion 50B. Due to this first adhesive removing step, an adhesive portion 52 other than the tip portion 51 remains at the terminal end portion 14 of the fiber bundle 20 . If the photoresponsive adhesive 40 at the tip portion 51 of the bonding portion 50B softened by the first adhesive softening step becomes liquid and flows down from the fiber bundle 20, the first adhesive removing step is performed. can be omitted.

The end face 70A of the spliced end portion 70 of the fiber bundle 20 treated in this manner is made flush by the cutting process described above. As shown in FIG. 1H, the spliced end portion 70 of the fiber bundle 20 and the end portion 85 of the output optical fiber 80 are opposed to each other and spliced together by, for example, fusion splicing (fiber splicing step). The output optical fiber 80 includes a core (not shown), a clad 82 surrounding the core, and a coating 83 surrounding the clad 82. The coating 83 at the end 85 of the output optical fiber 80 is removed and the clad 82 is exposed to the outside. The clad 82 has a lower refractive index than the core, and an optical waveguide is formed inside the core.

The input optical fiber 10 and the output optical fiber 80 can function as an optical combiner. When a high-power laser beam propagates, such a laser beam may enter the photoresponsive adhesive 40 of the bonding portion 52, causing the photoresponsive adhesive 40 to generate heat. For this reason, it is preferable to remove the photoresponsive adhesive 40 from the bonding portion 52 after the fiber bonding process.

When removing the photoresponsive adhesive 40 from the bonding portion 52 after the fiber bonding step, first, the photoresponsive adhesive 40 from the bonding portion 52 is softened (second adhesive softening step). In the second adhesive softening step in the present embodiment, as in the first adhesive softening step, the photoresponsive adhesive of the adhesive portion 52 is irradiated with softening light as shown in FIG. 1I. 40 soften.

Then, the softened photoresponsive adhesive 40 is removed from the end portion 14 of the fiber bundle 20 (second adhesive removing step). In this second adhesive removing step, similarly to the first adhesive removing step, for example, the adhesive portion 52 is immersed in a solvent to remove the photoresponsive adhesive 40 from the adhesive portion 52, and then the solvent is washed away. Alternatively, the photoresponsive adhesive 40 of the adhesive portion 52 may be removed by dry cleaning the adhesive portion 52 .

By removing the photoresponsive adhesive 40 in this manner, an optical combiner 90 in which a plurality of input optical fibers 10 and one output optical fiber 80 are joined is completed as shown in FIG. 1J.

As described above, according to the present embodiment, the end faces of the input optical fibers can be aligned without causing the end faces of the plurality of input optical fibers to abut on the plane of the adjustment tool as in the conventional art. Damage to the tip of the input optical fiber 10 is reduced. For this reason, it is possible to suppress a decrease in joint strength and an increase in connection loss when the input optical fiber 10 and the output optical fiber 80 are joined.

In this embodiment, as the reversible adhesive 40, an adhesive (photoresponsive adhesive) having a property of being reversibly cured and softened by irradiation with light is used. good too. For example, the reversible adhesive 40 may be an adhesive that is cured by irradiation of light and softened by heating, or an adhesive (thermoplastic resin) that is cured and softened by changes in temperature. .

Here, for example, when using a material that reversibly hardens and softens due to a change in temperature as the reversible adhesive 40, a complicated mechanism is required to change the temperature. Since the mechanism for this can be realized with a relatively simple structure, by using a photoresponsive adhesive as the reversible adhesive 40 as in the present embodiment, the optical combiner can be manufactured with a simple apparatus. can.

In the present embodiment, the reversible adhesive 40 is a photoresponsive adhesive having a property of being cured by irradiation of light. However, the treatment performed in the bond forming process will vary depending on the means by which the reversible adhesive 40 is cured. For example, if the reversible adhesive 40 is to be hardened by cooling, it is cooled in the first adhesive softening process and the second adhesive softening process.

In addition, in the present embodiment, since a photoresponsive adhesive having a property of being softened by light irradiation is used as the reversible adhesive 40, the first softening light irradiation step of the first adhesive softening step described above is performed. and in the second adhesive softening step of the second softening light irradiation step, the softening light is irradiated respectively, but the treatments performed in the first adhesive softening step and the second adhesive softening step are reversible It varies depending on the means by which the adhesive 40 is softened. For example, when using a reversible adhesive 40 that has a property of being softened by heating, heating is performed in the first adhesive softening step and the second adhesive softening step.

Next, a method for manufacturing an optical combiner according to the second embodiment of the present invention will be described. In this embodiment, as in the first embodiment, as the reversible adhesive 40, an adhesive (photoresponsive adhesive) having a property of being reversibly cured and softened by light irradiation is used. Although explained, it goes without saying that other reversible adhesives may be used.

First, as in the first embodiment, a plurality of input optical fibers 10 are bundled to form a fiber bundle 20 (fiber bundle forming step). Then, as shown in FIG. 2A, the dispenser 101 is used to drip the reversible adhesive 40 onto the terminal end portion 14 of the fiber bundle 20 to adhere the reversible adhesive material 40 to the terminal end portion 14 of the fiber bundle 20 (adhesion). material dripping process). In this adhesive dropping step, the reversible adhesive 40 may be dropped onto at least a portion of the terminal portion 14 of the fiber bundle 20 .

Next, as shown in FIG. 2B, the reversible adhesive 40 (photoresponsive adhesive) attached to the end portion 14 of the fiber bundle 20 in this way is irradiated with curing light, whereby the reversible adhesive 40 is cured. is cured (curing light irradiation step). As a result, at least part of the terminal end 14 of the fiber bundle 20 is formed an adhesive portion 50 in which the plurality of input optical fibers 10 are adhered to each other with the photoresponsive adhesive 40 .

Subsequent steps are the same as the steps after the cutting step in the first embodiment. That is, the adhesive portion 50 is cut at a predetermined cutting position in the longitudinal direction, and the tip portion of the adhesive portion 50 is removed (cutting step). Thereafter, the reversible adhesive 40 at the tip of the remaining adhesive portion 50 is softened (first adhesive softening step), the softened reversible adhesive 40 is removed from the fiber bundle 20, and the input optical fiber 10 is removed. forming a joint end where the cladding 12 of is exposed (first adhesive removing step). Then, the spliced end portion of the fiber bundle 20 and the end portion of the output optical fiber are made to face each other, and these are spliced together by, for example, fusion splicing (fiber splicing step). Preferably, after this, the reversible adhesive 40 in the remaining adhesive portion 50 is softened (second adhesive softening step), and the softened reversible adhesive 40 is removed from the fiber bundle 20 (second adhesive material removal process).

In this embodiment, the reversible adhesive 40 is applied to the terminal end 14 of the fiber bundle 20 by dropping the reversible adhesive 40 onto the terminal end 14 of the fiber bundle 20 using the dispenser 101. Since it is not necessary to prepare the container 30 holding the reversible adhesive 40 as in the first embodiment, the required amount of the reversible adhesive 40 can be reduced.

Next, a method for manufacturing an optical combiner according to the third embodiment of the present invention will be described. In this embodiment, an adhesive film formed from the above-described photoresponsive adhesive is used. First, as shown in FIG. 3, an adhesive film 240 made of such a photoresponsive adhesive is wound around at least a portion of the end portion 14 of the fiber bundle 20 (adhesive winding step). As a result, at least a portion of the terminal portion 14 of the fiber bundle 20 forms a bonding portion where the plurality of input optical fibers 10 are bonded together by the photoresponsive adhesive 40 .

If the plurality of input optical fibers 10 are not sufficiently adhered only by winding the adhesive film 240 around the end portion 14 of the fiber bundle 20, the adhesive film 240 is irradiated with curing light after the adhesive winding step described above. By doing so, the adhesive film 240 may be cured (curing light irradiation step) to form an adhesive portion on at least a part of the end portion 14 of the fiber bundle 20 .

Subsequent steps are the same as the steps after the cutting step in the first embodiment. That is, the adhesive portion is cut at a predetermined cutting position in the longitudinal direction to remove the tip portion of the adhesive portion (cutting step). Thereafter, the adhesive film 240 at the tip of the remaining adhesive portion is softened (first adhesive softening step), the softened adhesive film 240 is removed from the fiber bundle 20, and the clad 12 of the input optical fiber 10 is exposed. forming a joint end portion (first adhesive removing step). Then, the spliced end portion of the fiber bundle 20 and the end portion of the output optical fiber are made to face each other, and these are spliced together by, for example, fusion splicing (fiber splicing step). Preferably, thereafter, the adhesive film 240 in the remaining adhesive portion is softened (second adhesive softening step), and the softened adhesive film 240 is removed from the fiber bundle 20 (second adhesive removing step).

In this embodiment, since a film-like photoresponsive adhesive (adhesive film 240) is used, the operation of applying the photoresponsive adhesive to the terminal end portion 14 of the fiber bundle 20 to form the adhesive portion is the first. It is easier than the first embodiment.

As described above, according to one aspect of the present invention, there is provided a method for manufacturing an optical combiner that can easily suppress a decrease in joint strength and an increase in connection loss when an input optical fiber and an output optical fiber are joined. is provided. This method includes a fiber bundle forming step of bundling a plurality of input optical fibers having terminal ends with exposed claddings to form a fiber bundle, and the terminal end of the fiber bundle formed by the fiber bundle forming step. a reversible adhesive having a property of reversibly hardening and softening is applied to at least a part of the bonding portion to form a bonding portion in which the plurality of input optical fibers are bonded to each other by the reversible adhesive. a forming step; a cutting step of cutting the adhesive portion formed by the adhesive portion forming step at a predetermined cutting position in the longitudinal direction to remove a tip side of the adhesive portion; and the adhesive portion remaining after the cutting step. a first adhesive softening step of softening the reversible adhesive at the distal end portion of the first adhesive softening step; and a spliced end portion where the cladding of the plurality of input optical fibers is exposed and output light after the first adhesive softening step and a fiber splicing step of splicing the ends of the fibers together.

In this way, by cutting the bonded portion where a plurality of input optical fibers are bonded to each other with a reversible adhesive, the end portions of the respective input optical fibers can be cut in the same plane. The endfaces of the terminations of multiple input optical fibers can be easily flushed without the need for experience. By softening the reversible adhesive material at the tip of the adhesive portion remaining after cutting, a joint end portion having a flush end face can be formed. It can be spliced with the end of the fiber. According to the method of the present invention, it is not necessary to bring the end faces of a plurality of input optical fibers into contact with the flat surface of the adjustment tool as in the prior art, and damage to the tips of the input optical fibers is reduced. It is possible to suppress a decrease in joint strength and an increase in connection loss when the optical fiber is joined to the output optical fiber.

The method further includes a first adhesive removing step of removing the reversible adhesive softened by the first adhesive softening step from the end of the fiber bundle to form the splice end. You can

The method includes, after the fiber joining step, a second adhesive softening step of softening the reversible adhesive of the bonded portion, and the reversible adhesive softened by the second adhesive softening step. and a second adhesive removal step of removing from the fiber bundle. After the input optical fiber and the output optical fiber are joined in this way, by removing the reversible adhesive from the remaining adhesive portion, for example, when high-power laser light propagates through the optical combiner, the laser light can be suppressed from entering the remaining reversible adhesive and generating heat.

As the reversible adhesive, a photoresponsive adhesive having a property of being cured by irradiation with light having a predetermined curing wavelength can be used. As the reversible adhesive, for example, when using a material (thermoplastic resin) that reversibly hardens and softens due to changes in temperature, a complicated mechanism is required to change the temperature. Since the mechanism for irradiation can be realized with a relatively simple structure, the use of a photoresponsive adhesive as the reversible adhesive allows the optical combiner to be manufactured with a simple apparatus.

The bonding portion forming step includes a fiber dipping step of immersing the tip of the terminal end of the fiber bundle in the liquid photoresponsive adhesive to adhere the photoresponsive adhesive to the tip of the terminal end; and a curing light irradiation step of curing the photoresponsive adhesive by irradiating light of the curing wavelength to the photoresponsive adhesive adhered to the tip of the terminal end portion by the fiber immersion step. good. By immersing the liquid photoresponsive adhesive at the tip of the fiber bundle end portion by such a fiber dipping process, the reversible adhesive penetrates between the clads at the end portion of the fiber bundle. can be evenly attached to the ends of the fiber bundles.

Alternatively, the bonding portion forming step includes: an adhesive dropping step of dropping the photoresponsive adhesive onto at least a portion of the terminal portion of the fiber bundle; and a curing light irradiation step of irradiating the dropped photoresponsive adhesive with light of the curing wavelength to cure the photoresponsive adhesive. By dropping the photoresponsive adhesive onto at least a part of the end portion of the fiber bundle by such an adhesive dropping step, the required amount of the photoresponsive adhesive can be reduced.

Alternatively, the bonding portion forming step may include an adhesive winding step of winding the film-like photoresponsive adhesive on at least a portion of the end portion of the fiber bundle. In addition, the bonding portion forming step includes irradiating the photoresponsive adhesive wound around at least a part of the end portion in the adhesive winding step with light of the curing wavelength to irradiate the photoresponsive adhesive. A curing light irradiation step for curing may be further included. By using the film-like photoresponsive adhesive in this manner, the operation of applying the photoresponsive adhesive to the end portion of the fiber bundle to form the adhesive portion is simplified.

The photoresponsive adhesive may have a property of being softened by irradiation with light having a predetermined softening wavelength. In this case, the first adhesive softening step includes a light shielding member disposing step of disposing a light shielding member so as to cover at least a portion of the adhesive portion other than the tip portion, and and a first softening light irradiation step of irradiating the adhesive portion with light to soften the photoresponsive adhesive. The reversible adhesive material at the tip of the adhesive portion can be easily softened by such a light shielding member placement step and the first softening light irradiation step.

As the reversible adhesive, a photoresponsive adhesive having a property of being cured by irradiation with light of a predetermined curing wavelength and softened by irradiation of light of a predetermined softening wavelength may be used. In this case, the second adhesive softening step may include a second softening light irradiation step of irradiating the bonding portion with light of the softening wavelength to soften the photoresponsive adhesive. According to this method, the photoresponsive adhesive can be softened only by irradiating the bonding portion with the light of the softening wavelength, so that the photoresponsive adhesive can be easily removed from the bonding portion.

Although the preferred embodiments of the present invention have been described so far, it goes without saying that the present invention is not limited to the above-described embodiments and may be embodied in various forms within the scope of its technical concept.

REFERENCE SIGNS LIST 10 input optical fiber 11 core 12 cladding 13 coating 14 termination 20 fiber bundle 30 container 40 reversible adhesive (photoresponsive adhesive)
50, 52 Adhesive Part 51 Tip Part 60 Light Shielding Member 70 Joining End Part 70A End Face 80 Output Optical Fiber 82 Cladding 83 Coating 85 End Part 90 Optical Combiner 101 Dispenser 240 Adhesive Film

Claims (10)

a fiber bundle forming step of forming a fiber bundle by bundling a plurality of input optical fibers having terminal ends where the cladding is exposed to the outside;
A reversible adhesive having a property of reversibly hardening and softening is applied to at least a part of the terminal portion of the fiber bundle formed by the fiber bundle forming step, so that the plurality of input optical fibers are reversibly a bonding portion forming step of forming bonding portions bonded to each other with a flexible adhesive;
a cutting step of cutting the adhesive portion formed in the adhesive portion forming step at a predetermined cutting position in the longitudinal direction to remove the tip side of the adhesive portion;
a first adhesive softening step of softening the reversible adhesive at the tip of the adhesive portion remaining after the cutting step;
A method for manufacturing an optical combiner, comprising a fiber joining step of joining the joining ends of the plurality of input optical fibers where the cladding is exposed and the ends of the output optical fibers to each other after the first adhesive softening step. . 2. The method of claim 1, further comprising a first adhesive removing step of removing the reversible adhesive softened by the first adhesive softening step from the end of the fiber bundle to form the splice end. A method of manufacturing the described optical combiner. a second adhesive softening step of softening the reversible adhesive of the bonded portion after the fiber bonding step;
3. The method of manufacturing an optical combiner according to claim 1, further comprising a second adhesive removing step of removing said reversible adhesive softened by said second adhesive softening step from said fiber bundle. 4. The method of manufacturing an optical combiner according to any one of claims 1 to 3, wherein the reversible adhesive is a photoresponsive adhesive having a property of being cured by irradiation with light having a predetermined curing wavelength. The bonding portion forming step includes:
a fiber dipping step of immersing the tip of the terminal portion of the fiber bundle in the liquid photoresponsive adhesive to adhere the photoresponsive adhesive to the tip of the terminal portion;
a curing light irradiation step of curing the photoresponsive adhesive by irradiating light of the curing wavelength to the photoresponsive adhesive adhered to the tip of the terminal portion by the fiber immersion step;
5. A method of manufacturing an optical combiner according to claim 4. The bonding portion forming step includes:
an adhesive dropping step of dropping the photoresponsive adhesive onto at least a portion of the terminal portion of the fiber bundle;
a curing light irradiation step of curing the photoresponsive adhesive by irradiating the photoresponsive adhesive dropped onto at least a part of the end portion by the adhesive dropping step with light of the curing wavelength to cure the photoresponsive adhesive;
5. A method of manufacturing an optical combiner according to claim 4. 5. The method of manufacturing an optical combiner according to claim 4, wherein said bonding portion forming step includes an adhesive winding step of winding said film-like photoresponsive adhesive around at least a portion of said end portion of said fiber bundle. In the adhesion portion forming step, the photoresponsive adhesive wound around at least a part of the end portion in the adhesive winding step is irradiated with light of the curing wavelength to cure the photoresponsive adhesive. 8. The method of manufacturing a light combiner according to claim 7, further comprising a curing light irradiation step. The photoresponsive adhesive has a property of being softened by irradiation with light having a predetermined softening wavelength,
The first adhesive softening step includes:
A light shielding member arranging step of arranging a light shielding member so as to cover at least a portion of the adhesive portion other than the tip portion;
a first softening light irradiation step of irradiating the adhesive portion with light of the softening wavelength through the light shielding member to soften the photoresponsive adhesive;
A method for manufacturing an optical combiner according to any one of claims 4 to 8. As the reversible adhesive, a photoresponsive adhesive having a property of being cured by irradiation of light of a predetermined curing wavelength and softened by irradiation of light of a predetermined softening wavelength is used,
The second adhesive softening step includes a second softening light irradiation step of irradiating the adhesive portion with light of the softening wavelength to soften the photoresponsive adhesive.
4. A method of manufacturing an optical combiner according to claim 3.

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