JP2002341172A - Method of manufacturing optical fiber welded part reinforcing member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of inexpensively manufacturing optical fiber welded part reinforcing members having high mechanical strength to improve reliability while maintaining the advantage of crystallized glass of low thermal expansion. SOLUTION: This method of manufacturing the optical fiber welded part reinforcing members of the approximately planar or bar form consisting of the crystallized glass of low thermal expansion comprises forming a glass body to form cast glass G having surface approximately parallel to the optical fibers having a welded part and the prescribed cross section shape, subjecting the cast glass G to cold working to manufacture an approximately planar or bar- form glass member G' having a prescribed size and shape and heat treating the glass member G' in a heat treatment furnace 10 to precipitate crystals thereby forming the surface layers of the β-quartz solid solution crystals or the surface layers of the β-spodumene crystals on the surface approximately parallel to the optical fibers having the welded part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a reinforcing member used to reinforce a fused portion of an optical fiber.

[0002]

2. Description of the Related Art One of the methods for connecting optical fibers is a method in which the ends of the optical fibers are heated and fused in a state where the ends of the optical fibers are abutted. In addition, as one type of optical fiber coupler, there is a so-called fusion type coupler in which a plurality of optical fibers are arranged in parallel, heated and fused, and then stretched to reduce the diameter. In order to protect such a fused portion of the optical fiber from breakage or the like, measures such as fixing and reinforcing with a reinforcing member via an adhesive are taken, and the reliability of the connection portion of the optical fiber and the optical fiber coupler is improved. It is planned.

[0003] As shown in FIG. 4, a reinforcing member used for fixing the fused portion of the optical fiber includes a fused portion 2 of the optical fiber 1.
There is a member made of a pair of plate-like or rod-like members which sandwich the optical fiber 1 from above and below. In order to fix the fused portion 2 of the optical fiber 1 using such reinforcing members 3 and 4,
A thermoplastic adhesive 5 which is softened by heating and hardened in a short time by cooling is applied and fixed on the upper surface of the substrate, and the fused portion 2 is positioned substantially at the center of the reinforcing member 4 thereon. The optical fiber 1 is placed, and the other reinforcing member 3 to which the adhesive 5 is similarly applied and fixed is placed thereon, and the upper and lower reinforcing members 3 and 4 are heated and bonded to each other. A method of reinforcing by fixing 2 is adopted.

As the reinforcing members 3 and 4 used for fixing the fused portion 2 of the optical fiber 1, heat is applied to the optical fiber 1 at the portion where the fused portion 2 of the quartz optical fiber 1 is fixed. A material that does not generate stress and is not deformed is preferable, and quartz glass, crystallized glass, or the like having a low thermal expansion is known as a material satisfying such conditions.

There are various types of reinforcing members 3 and 4 such as a rod-like member obtained by dividing a round bar or a cylinder into half and a plate-like member.

Conventionally, a bar-shaped reinforcing member 3 obtained by dividing the above-mentioned round bar in half has been manufactured, for example, through a process as shown in FIG. First, a glass material is formed into a round bar shape by a down-draw method or an up-draw method, and a round bar-shaped glass as shown in FIG. Microcrystals are precipitated to obtain a round bar M of crystallized glass. The round bar M of the crystallized glass is ground to a predetermined shape in the radial direction with a diamond grinding wheel to obtain a rod-shaped crystallized glass M ′ having a substantially half-moon-shaped cross section as shown in FIG. Then, the rod-shaped crystallized glass is cut into a predetermined length as shown in FIG. 5 (C), and the reinforcing member 3 has a flat surface on one side and a substantially half-moon-shaped convex on the other side. Has been produced.

The flat reinforcing member 4 is manufactured by grinding and polishing a crystallized glass plate to a predetermined thickness, and then cutting it.

[0008]

The above-mentioned reinforcing members 3, 4
Crystallized glass, which is a material of the above, is not easy to process such as cutting or cutting because the hardness of precipitated crystals is high, and when performing such machining, it becomes a site where bending stress is concentrated. Fine cracks such as latent scratches enter the surface 3a of the reinforcing member 3, which is the portion where the fused portion 2 of the optical fiber 1 is fixed, causing a decrease in mechanical strength.

As a countermeasure against this, conventionally, the reinforcing members 3 and 4 made of crystallized glass are finished to a predetermined size and shape by subjecting a material made of crystallized glass to machining such as cutting or grinding, and then to mechanical strength. In order to improve the quality, a process by ion exchange is performed.

In such an ion exchange treatment, glass is immersed in a heated molten salt, and alkali ions such as Na having a small radius of the element in the glass and alkali ions such as K having a large radius of the element of the molten salt are contained in the glass. Is a glass strengthening method that forms a compressive stress in the surface layer of the glass to increase the strength by replacing the glass, and has a higher strength than other glass strengthening methods such as air-cooling. It is advantageous in that it is not restricted by wall thickness and the like, and that high deformation accuracy can be obtained because no deformation occurs.

However, there is a problem in that the ion exchange treatment requires a long time and thus increases the cost.

Further, the reinforcing member 3 of the fused portion 2 of the optical fiber 1 needs to go through many steps such as forming, crystallizing, grinding, cutting, etc. of a round bar glass before completion. Finally, only about 20% of the round bar-shaped glass used as a material is finally used as a finished product, and most of the material is processed glass waste, so that the utilization rate of the material is extremely low.

[0013] The present invention has been made in view of the above problems, and while maintaining the advantages of crystallized glass having low thermal expansion,
It is possible to greatly simplify the manufacturing process and manufacture inexpensively a reinforcing member for an optical fiber fusion splice with high mechanical strength enough to improve the reliability of the fusion spliced optical fiber connection and the optical fiber coupler. It is an object of the present invention to provide a manufacturing method which can be performed.

[0014]

In order to solve the above-mentioned problems, a method of manufacturing a reinforcing member for an optical fiber fusion splicing member according to the present invention comprises a substantially plate-like or rod-like optical fiber fusion member made of crystallized glass having a low thermal expansion. In the manufacturing method of the bonding part reinforcing member, a glass material is formed to form a molded product having a surface substantially parallel to the optical fiber having a fusion bonded portion and a predetermined cross-sectional shape, and the molded product is cold-processed. To produce a substantially plate-shaped or rod-shaped glass member having a predetermined size and shape, and heat-treating the glass member to precipitate a crystal, whereby β is formed on a surface substantially parallel to the optical fiber having a fusion bonded portion. Forming a surface layer of quartz solid solution crystals or a surface layer of β-spodumene crystals;

In the method for manufacturing a reinforcing member for an optical fiber fusion splice according to the present invention, a surface layer of β-quartz solid solution crystals (β-SiO ₂ solid solution) deposited on the surface or a β-spodumene solid solution crystal (β-Li ₂ O)・ A
l ₂ O ₃ · 4SiO ₂ solid solution)
It is as-deposited by being subjected to heat treatment, and is structurally different from the β-quartz solid solution crystal or β-spodumene crystal exposed from the inside where the surface layer of the reinforcing member is removed by grinding or the like. is there. In addition, it is important to form a surface layer of β-quartz solid solution crystal or a surface layer of β-spodumene crystal in a portion where bending stress is concentrated when a bending moment load is applied to the reinforcing member of the optical fiber fusion portion. In the case of an elongated shape, the central portion in the longitudinal direction is a portion where the bending stress is concentrated. Forming a surface layer at the time of β-quartz solid solution crystal precipitation or a surface layer at the time of β-spodumene crystal precipitation on almost the entire surface of the reinforcing member substantially parallel to the fusion portion 2 of the optical fiber 1 is directional. Irrespective of this, it is preferable to maintain the mechanical strength of the optical fiber fusion splice reinforcing member.

As the low thermal expansion crystallized glass used for the reinforcing member of the optical fiber fusion splicing part manufactured in the present invention, for reinforcing the optical fiber fusion splicing part, a β-quartz solid solution crystal is used as a main crystal to be transparent. Neoceram N-0 manufactured by Nippon Electric Glass Co., Ltd. is suitable. Being compatible with the thermal expansion coefficient of quartz glass
Neoceram N-11 manufactured by NEC Corporation and exhibiting white color with spodumene crystal as the main crystal is suitable.

Further, according to the method of the present invention for manufacturing an optical fiber fusion splice reinforcing member, a glass article is formed to form a molded article having a plurality of projections, and the plurality of projections are separated from the molded article. A substantially plate-shaped or rod-shaped glass member having substantially the same cross-sectional dimension and shape as the reinforcing member is produced.

To form a molded product having a plurality of convex portions using a glass material means that a glass material having crystallinity is supplied to a female mold and then pressed by a male mold, and a groove having a predetermined shape is provided. It refers to forming to supply a glass substrate having crystallinity between rotating rollers, forming to supply a glass substrate having crystallinity to a mold having a recess having a predetermined shape, and the like. In addition, as a molded product having a plurality of convex portions, a molded product in which convex portions such as a semi-cylindrical shape are formed in parallel on a plate-like glass, and a rod-shaped convex portion having a predetermined shape is formed from a base portion. A molded product or the like may be used as long as a substantially plate-shaped or rod-shaped glass member having substantially the same cross-sectional dimension and shape as the reinforcing member can be separated by cutting, short-time grinding or polishing, or the like.

[0019]

According to the method of manufacturing an optical fiber fused portion reinforcing member of the present invention, in the method of manufacturing a substantially plate-shaped or rod-shaped optical fiber fused portion reinforcing member made of crystallized glass having low thermal expansion, a glass material is formed. Forming a molded product having a surface substantially parallel to the optical fiber having the fused portion and a predetermined cross-sectional shape, and subjecting the molded product to cold working to obtain a substantially plate-shaped or rod-shaped product having a predetermined size and shape. Since the glass member is manufactured, a glass member that can be easily machined can be mass-produced. Then, the glass member is heat-treated to precipitate a crystal, whereby β is formed on a surface substantially parallel to the optical fiber fusion spliced portion. Forming a surface layer of a quartz solid solution crystal or a surface layer of a β-spodumene crystal, so that the surface layer or the β-spodumene at the time of β-quartz solid solution crystal deposition is substantially parallel to the surface including the surface facing the fusion portion of the optical fiber; Crystal precipitation An optical fiber fusion splice reinforcement member with a surface layer formed on it can be manufactured. Cracks do not grow and high mechanical strength can be maintained.

Further, according to the method of manufacturing an optical fiber fusion splicer reinforcing member according to the present invention, a glass material is formed to form a molded product having a plurality of convex portions, and the plurality of convex portions are separated from the molded product. To produce a substantially plate-shaped or rod-shaped glass member having substantially the same cross-sectional dimensions as the reinforcing member, so that there is almost no need for grinding and the manufacturing process can be greatly simplified. Only a small amount of debris is generated, and the glass material can be used effectively.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing an optical fiber fusion splice reinforcing member of the present invention will be described in detail with reference to examples.

First, an optical fiber fusion splice reinforcing member manufactured according to the present invention will be described. FIG. 1 is a perspective view of a reinforcing member of an optical fiber fusion splicing part according to the present invention, FIG. 2 is an explanatory view showing a manufacturing process of the optical fiber fusion splicing member according to the present invention, and FIG. FIG. 6 is an exploded perspective view when fixing a fusion bonding portion with a reinforcing member. In each of the figures, reference numeral 11 denotes an optical fiber, 12 denotes a fused portion, 13 and 14 denote reinforcing members, and 15 denotes an adhesive.

As the optical fiber 11, there are single-core and plural-core optical fibers, but any one may be used. The fusion portion 12 of the optical fiber 11 is heated and fusion-bonded by abutting the ends of the optical fiber 11 with each other and heating or fusion-splicing, as in an optical fiber coupler. After being attached, there is one that is formed into a small diameter by stretching.

As shown in FIG. 1, the reinforcing members 13 and 14 have a predetermined size and shape, and
Substantially parallel surfaces 13a, 13 including a surface facing the fused portion 12.
b, 14a, 14b, by heat treatment, having a surface layer at the time of β-quartz solid solution crystal precipitation, for example, having a surface layer at the time of deposition of Neoceram N-0 or β-spodumene crystal by Nippon Electric Glass Co., Ltd., for example Made of low thermal expansion crystallized glass such as Neoceram N-11 manufactured by NEC Corporation. The thermal expansion coefficients of the reinforcing members 13 and 14 are as follows:
Coefficient of thermal expansion of quartz glass constituting optical fiber 1 4 × 1
Those substantially equivalent to 0 ^-7 / ° C are preferred.

The fused portion 12 of the optical fiber 11 is formed by using a crystallized glass such as Neoceram N-0 having transparency.
Β- on the surfaces 13a, 13b, 14a and 14b substantially parallel to
Reinforcing member 1 having surface layer during quartz solid solution crystal precipitation
If the members 3 and 14 are manufactured, the state of the fused portion 12 of the optical fiber 11 can be externally observed during and after the reinforcing work, and the reinforcing member 13 having a substantially half-moon-shaped cross section can be observed.
Then, the fused portion 1 of the optical fiber 11 is
The state of No. 2 is enlarged and can be observed better.

As the adhesive 15 shown in FIG.
A thermoplastic adhesive which softens and melts by heating and cures in a short time by cooling is suitable, and a transparent adhesive is more preferable.

Next, a method of manufacturing the optical fiber fusion splice reinforcing member according to the present invention will be described.

The transparent reinforcing member 13 of the fused portion of the optical fiber of the present invention is manufactured through the steps shown in FIG.

First, in mass%, SiO_Two 67%, Al_TwoO
_Three 23%, Li_TwoO 4%, TiO _Two 2%, ZrO_Two 
3%, P_TwoO_Three 1% glass raw material is melted
The glass fabric obtained from
Are formed in a plurality of rows and the surface is a plain flat surface.
The rollers are arranged facing each other up and down with a certain interval, and
Roll forming device where each roller rotates (not shown)
To the roller and pass through the gap between the two rotating rollers.
The cross-section formed on the roller on one side of the lath fabric is almost half-moon-shaped.
The recess is transferred, and the cross section is on one side as shown in FIG.
90 mm long template plate having a plurality of rows of substantially half-moon-shaped protrusions
Obtain Lass G.

Next, the template glass G is cut into a length of 40 mm, and cut along a chord of a substantially half-moon-shaped cross section formed on one side with a diamond cutter wheel, a wire saw, or the like, to thereby obtain FIG. As shown in ()), a glass member is obtained by separating a bar-shaped glass having a length of about 8.7 mm, a length of chord of 7.7 mm, and a height of about 1.8 mm, and having a substantially half-moon-shaped cross section. G ′ is prepared.

Finally, the glass member G 'is connected to the glass member G' as shown in FIG.
And held for 1 hour while controlling the temperature in a high-temperature atmosphere of 850 to 950 ° C., a β-quartz solid solution crystal having a surface layer of several nm precipitates on the glass member G ′ to form a glass. The member G ′ is crystallized, and the desired reinforcing member 13 is completed.

In order to obtain a template glass G having a plurality of rows of convex portions having a substantially half-moon cross section on one side, the present invention is not limited to the above-described method, and a part of a circle having a radius of 5.0 mm can be cut off on the surface. Arc length 8.7mm, chord length 7.7mm, height 1.8
a male type in which a plurality of rows of recesses having a substantially half-moon-shaped cross section of
The male mold is pressed against the glass cloth placed on the surface of the female mold using a press molding device (not shown) composed of a female mold having a plain flat surface, and the cross section formed in the male mold is approximately half a month. It is also possible by a method of transferring the concave portion of the shape.

The time required to manufacture 1500 pieces of the above-mentioned reinforcing members 13 is one hour, which is greatly shortened to one third as compared with the conventional manufacturing method.

Next, the reinforcing member 13 according to the embodiment of the present invention will be described.
Was evaluated. As an evaluation sample, the coefficient of thermal expansion was −6 ×
10 ^-7 / K, which is almost the same as the thermal expansion coefficient of quartz glass constituting the optical fiber, 4 × 10 ^-7 / K, which is small and has a cross-sectional shape of 8.7 mm in arc length and 7. Fifty rod-shaped reinforcing members 13 having a length of 40 mm and a substantially half-moon cross section of 7 mm and a height of 1.8 mm were prepared.

The sample of Comparative Example 1 has a dimension of 40 mm in length having a substantially half-moon-shaped cross section of 8.7 mm in arc length, 7.7 mm in chord length, and 1.8 mm in height by grinding. 50 samples of the rod-shaped reinforcing member having the following were prepared.

The sample of Comparative Example 2 has a dimension of 40 mm in length having a substantially half-moon-shaped cross section of 8.7 mm in arc length, 7.7 mm in chord length, and 1.8 mm in height by grinding. After preparing a rod-shaped body having the following, 50 samples of the reinforcing member reinforced by ion exchange treatment were prepared.

In order to evaluate the bending strength of the example and comparative examples 1 and 2, each sample was subjected to a three-point bending strength test. The measurement conditions were as follows: Shimadzu Autograph Tester (Model AGS
-500D), the tip R of the punch used is 6 mm,
Span = 30mm, crosshead speed = 0.5mm
The breaking load was measured under the condition of / min. Table 1 shows the results.

[0038]

[Table 1]

The reinforcing member 3 of the embodiment is 3.3 to 7.5 k.
gf, which has a high transverse rupture strength with a high breaking load of 5.8 kgf on average, comparable to Comparative Example 2 which is strengthened by the ion exchange treatment actually used, and can withstand practical use. I have.

On the other hand, the reinforcing member of Comparative Example 1 had a breaking load of 2.8 to 8.0 kgf, an average of 5.0 kgf, and a level of bending strength at a level of poor reliability as a reinforcing member.

A reinforcing member 1 made of crystallized glass having a β-quartz solid solution crystal having a substantially half-moon-shaped cross section is deposited.
No. 3 has high transparency of visible light transmittance of 85% or more in addition to the above-mentioned characteristics, and externally observes the state of the fused portion 12 of the optical fiber 11 during and after the reinforcing work. As a result, the state of the fused portion 12 of the optical fiber 11 was enlarged by the lens action so that the state could be better observed, so that the presence or absence of a reinforcing work error could be easily confirmed.

When the reinforcing member of the fused portion of the optical fiber of the present invention is subjected to an ion exchange treatment to form a compressive stress on the surface layer of the crystallized glass to increase the strength, the mechanical strength is further increased. Further, a highly reliable reinforcing member can be obtained.

[0043]

As described above, the method of manufacturing the reinforcing member of the optical fiber fusion splicing member according to the present invention comprises the steps of forming a glass material and forming a surface substantially parallel to the optical fiber having the fusion spliced portion and a predetermined sectional shape. Forming a molded product having a shape, and forming a substantially plate-shaped or rod-shaped glass member having a predetermined size and shape by cold-working the molded product, and heat-treating the glass member to precipitate crystals. Forming a surface layer of β-quartz solid solution crystal or a surface layer of β-spodumene crystal on a surface that is substantially parallel to the optical fiber fusion spliced part, so that a glass member that is easy to machine can be machined to produce an optical fiber fusion splice. The surface reinforcing member can be efficiently mass-produced, and a surface layer at the time of β-quartz solid solution crystal precipitation or a surface layer at the time of β-spodumene crystal precipitation is formed on a substantially parallel surface including a surface facing the optical fiber fusion portion. So that Fine cracks due to damage or latent damage do not grow near the fixing part of the optical fiber fusion part where the bending stress is concentrated, and high mechanical strength can be maintained without performing ion exchange. It is possible to manufacture an optical fiber fusion splice reinforcement member.

Further, according to the method of manufacturing an optical fiber fusion splice reinforcing member according to the present invention, a glass material is formed to form a molded product having a plurality of convex portions, and the plurality of convex portions are separated from the molded product. To produce a substantially plate-shaped or rod-shaped glass member having the same cross-sectional dimensions and shape as the reinforcing member, so that machining is easy, and grinding and ion exchange are not required, greatly simplifying the manufacturing process. Thus, the reinforcing member of the optical fiber can be manufactured at low cost.

Further, according to the method of manufacturing the reinforcing member for an optical fiber fusion splicing member of the present invention, only a very small amount of glass dust is generated by processing, and the glass material can be used effectively. It has excellent effects.

[Brief description of the drawings]

1A and 1B are explanatory views showing a reinforcing member of an optical fiber fusion spliced part of the present invention, wherein FIG. 1A is a perspective view of a reinforcing member having a substantially half-moon-shaped cross section, and FIG. The perspective view of a reinforcement member.

FIG. 2 is an explanatory view showing a step of producing a reinforcing member for an optical fiber fusion spliced part of the present invention, wherein (A) is a mold having a plurality of rows of convex portions having a substantially half-moon cross section on one surface. Sheet glass,
(B) is an explanatory view in which a bar-shaped glass having a substantially half-moon cross section and the remaining plate-shaped glass are separated, and (C) is an explanation in which a glass member having a required size and shape is cut and crystallized in a heat treatment furnace. FIG.

FIG. 3 shows a state in which an optical fiber fusion portion is fixed with a reinforcing member of the present invention.
FIG. 3 is an exploded perspective view when protecting.

FIG. 4 is an exploded perspective view when fixing and protecting an optical fiber fusion splice with a conventional reinforcing member.

5A and 5B are explanatory views showing a method for manufacturing a conventional reinforcing member for an optical fiber fusion splice, wherein FIG. 5A is an explanatory view of crystallizing a round bar glass in a heat treatment furnace, and FIG. Explanatory drawing which grinds and processes to the rod-shaped crystallized glass which has a substantially half moon-shaped cross section, (C) is explanatory drawing of the reinforcement member obtained by the conventional manufacturing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 11 Optical fiber 2, 12 Fused part 3, 4, 13, 14 Reinforcement member 5, 15 Adhesive 7, 10 Heat treatment furnace 13a, 13b, 14a, 14b Surface G type plate glass G 'Glass member

Continued on the front page F-term (reference) 2H036 MA11 PA12 PA14 4G062 AA01 BB06 DA06 DB04 DC01 DD03 DE01 DF01 EA03 EB01 EC01 ED01 EE01 EF01 EG01 FA01 FB03 FC03 FD01 FE01 FF01 FG01 FH01 FJ01 F01H01 H01 GA01 GA01 HH09 HH11 HH13 HH15 HH17 HH20 JJ01 JJ03 JJ05 JJ07 JJ10 KK01 KK03 KK05 KK07 KK10 MM04 MM08 NN33 QQ10

Claims (2)

[Claims] 1. A method of manufacturing a substantially plate-shaped or rod-shaped optical fiber fusion splice reinforcing member made of crystallized glass having a low thermal expansion, comprising: forming a glass cloth to be substantially parallel to an optical fiber having a fusion splice; And a molded product having a predetermined cross-sectional shape is formed, and a substantially plate-shaped or rod-shaped glass member having a predetermined size and shape is prepared by cold-working the molded product, and the glass member is heat-treated. Forming a surface layer of a β-quartz solid solution crystal or a surface layer of a β-spodumene crystal on a surface substantially parallel to the optical fiber having a fusion portion by depositing a crystal by welding. A method for manufacturing a reinforcing member. 2. A glass plate is formed to form a molded product having a plurality of convex portions, and the plurality of convex portions are separated from the molded product to have a substantially plate-like shape having substantially the same cross-sectional dimensions as the reinforcing member. The method according to claim 1, wherein a rod-shaped glass member is manufactured.