阅读说明：本技术 带透镜的光纤的制造方法、以及切断装置 (Method for manufacturing optical fiber with lens, and cutting device ) 是由 三须直树 于 2018-06-18 设计创作，主要内容包括：进行将保持于光纤保持架(20)的光纤(2)与保持于透镜保持架(30)的GRIN透镜(3)对接彼此的前端并熔接的工序；松缓透镜保持架(30)的保持力,并且使透镜保持架(30)向远离光纤保持架(20)的方向移动,而重新保持GRIN透镜(3)的工序；以及以与透镜保持架(30)的移动距离相等的长度切断GRIN透镜(3)的工序,从而生产率良好地并且高品质地制造在光纤的前端熔接棒状的GRIN透镜而成的带透镜的光纤。(A step of butt-jointing and welding the front ends of the optical fiber (2) held by the fiber holder (20) and the GRIN lens (3) held by the lens holder (30); a step of loosening the holding force of the lens holder (30), moving the lens holder (30) in a direction away from the optical fiber holder (20), and re-holding the GRIN lens (3); and a step of cutting the GRIN lens (3) by a length equal to the moving distance of the lens holder (30), thereby manufacturing the optical fiber with lens, which is formed by welding the rod-shaped GRIN lens at the front end of the optical fiber, with good productivity and high quality.)

1. A method for manufacturing a lensed optical fiber in which a GRIN lens formed in a long shape is coaxially fusion-spliced to a tip of an optical fiber and then the GRIN lens is cut into a rod shape by a predetermined length, the method comprising:

a step of butt-jointing and welding the optical fiber held by the fiber holder and the GRIN lens held by the lens holder to each other at the tip ends thereof;

a step of loosening the holding force of the lens holder, moving the lens holder in a direction away from the fiber holder, and re-holding the GRIN lens; and

and cutting the GRIN lens by a length equal to the moving distance of the lens holder.

2. The method of manufacturing a lensed optical fiber of claim 1, wherein,

the length for cutting the GRIN lens is set to L,

d represents a distance separating an end face of the optical fiber holder and an end face of the lens holder facing each other when the optical fiber and the GRIN lens are butt-jointed and fused to each other at their distal ends₀，

Setting the moving distance of the lens holding frame to Δ d when the GRIN lens is held again,

d represents a distance separating an end face of the optical fiber holder and an end face of the lens holder facing each other when the GRIN lens is cut,

d＝d₀+Δd

Δd＝L

the relationship of (1) holds.

3. The method of manufacturing a lensed optical fiber according to claim 1 or 2, wherein,

the respective steps are repeated by butting the remaining GRIN lenses after cutting against the tips of the newly prepared optical fibers while being held in the lens holder.

4. A cutting device for cutting an elongated GRIN lens, which is butt-jointed and fused with the front ends of optical fibers, by a predetermined length, the cutting device comprising:

an optical fiber holder placing section on which an optical fiber holder for holding the optical fiber is placed;

a lens holder mounting unit on which a lens holder for holding the GRIN lens is mounted; and

a cutting section disposed between the optical fiber holder mounting section and the lens holder mounting section,

the optical fiber holder placing part is provided with a positioning mechanism for positioning the placed optical fiber holder,

the lens holder placing section includes a positioning mechanism for positioning the lens holder placed thereon.

5. The shut-off device of claim 4,

a positioning concave portion which abuts against an end face and a side face of the optical fiber holder to position the optical fiber holder is engraved as the positioning means in the optical fiber holder placement portion,

the lens holder placement unit is engraved with a positioning concave portion that abuts against an end surface and a side surface of the lens holder to position the lens holder as the positioning means.

6. The shut-off device of claim 5,

the optical fiber holder mounting portion on which the positioning concave portion is engraved and the lens holder mounting portion on which the positioning concave portion is engraved are formed integrally by performing cutting processing on one member.

7. The cutoff device according to any one of claims 4 to 6,

the cutting blade unit of the cutting unit is supported by an XYZ rotary table.

Technical Field

The present invention relates to a method for manufacturing a lensed optical fiber in which a rod-shaped GRIN lens is fused to the tip of an optical fiber, and a preferred cutting device used in the method.

Background

There is known a lensed optical fiber in which a rod-shaped GRIN (Gradient Index) lens is fused to the tip of an optical fiber in order to enable efficient and low-loss coupling when coupling an optical fiber for transmitting an optical signal to an optical device such as a semiconductor laser, an optical switch, or an optical isolator (see patent documents 1 to 3).

In such a lensed optical fiber, in order to reduce transmission loss as much as possible, a GRIN lens that is precisely aligned at a predetermined length is fused to the tip of the optical fiber with high coaxiality. In patent document 1, the length of the lens is accurately and uniformly aligned by a method in which an optical fiber with a cut tip and an elongated body (elongated rod lens) of a GRIN rod lens with a cut tip are butt-jointed and fused to each other at their tips, and then the elongated rod lens is cut to a predetermined length.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open No. 2003-227963

Patent document 2: japanese patent application laid-open No. 4037346

Patent document 3: japanese patent application laid-open No. 4659137

Disclosure of Invention

Problems to be solved by the invention

However, a generally known optical fiber cutting device is configured to cut the end of an optical fiber and collect the cut portion as fiber debris. When the method of patent document 1 is carried out using such a cutting device, when cutting the long rod lens fused to the optical fiber, the optical fiber side can be relatively easily positioned by a clamping mechanism, a positioning adapter, or the like as shown in fig. 6 (i) of patent document 1, but there is no mechanism for restricting the position on the long rod lens side, and the positioning accuracy is poor.

Therefore, although according to the method of patent document 1, the lengths of the lenses are aligned accurately and uniformly, there is a limit in this respect, and improvement is required to improve the quality of the product and to improve the yield.

Further, it is not preferable from the viewpoint of cost because a long rod lens is consumed wastefully because a new long rod lens is prepared every time the long rod lens is fusion-spliced to an optical fiber, and the tip of the long rod lens is cut out and fusion-spliced to the optical fiber. Therefore, it is desired to manufacture a lensed optical fiber with good productivity without using a long rod lens wastefully.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a lensed optical fiber, which is capable of manufacturing a lensed optical fiber in which a rod-shaped GRIN lens is fused to the tip of the optical fiber, with high productivity and high quality, and a preferred cutting device used for the method.

Means for solving the problems

A method for manufacturing a lensed optical fiber according to the present invention is a method for manufacturing a lensed optical fiber in which a GRIN lens formed in a long shape is coaxially fusion-spliced to a tip of an optical fiber, and the GRIN lens is then cut into a rod-like shape by a predetermined length, the method comprising: a step of butt-jointing and welding the optical fiber held by the fiber holder and the GRIN lens held by the lens holder to each other at the tip ends thereof; a step of loosening the holding force of the lens holder, moving the lens holder in a direction away from the fiber holder, and re-holding the GRIN lens; and cutting the GRIN lens by a length equal to the moving distance of the lens holder.

A cutting device according to the present invention is a cutting device for cutting a long GRIN lens, which is butted and fused to the tip ends of optical fibers, by a predetermined length, the cutting device including: an optical fiber holder placing section on which an optical fiber holder for holding the optical fiber is placed; a lens holder mounting unit on which a lens holder for holding the GRIN lens is mounted; and a cutting unit disposed between the optical fiber holder placing unit and the lens holder placing unit, wherein the optical fiber holder placing unit includes a positioning mechanism for positioning the optical fiber holder placed thereon, and the lens holder placing unit includes a positioning mechanism for positioning the lens holder placed thereon.

Effects of the invention

According to the present invention, a lensed optical fiber in which a rod-shaped GRIN lens is fused to the tip of an optical fiber can be manufactured with high productivity and high quality.

Drawings

Fig. 1 is a process diagram schematically illustrating a method for manufacturing a lensed optical fiber according to an embodiment of the present invention.

Fig. 2 is a plan view schematically showing a main part of the cutting apparatus according to the embodiment of the present invention.

Fig. 3 is a front view showing an outline of a main part of the cutting device according to the embodiment of the present invention.

Fig. 4 is a sectional view a-a of fig. 2.

Fig. 5 is an explanatory diagram showing an example of use of the cutting device according to the embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[ method for producing lensed optical fiber ]

First, an outline of a method for manufacturing a lensed optical fiber according to the present embodiment will be described.

Fig. 1 is a process diagram schematically illustrating a method for manufacturing a lensed optical fiber according to the present embodiment.

In the present embodiment, a GRIN lens 3 formed in a long shape is coaxially welded to the tip of an optical fiber 2, and then the GRIN lens 3 is cut into a rod shape by a predetermined length to manufacture a lensed optical fiber 1.

A known optical fiber fusion-splicing device may be used to coaxially fuse the long GRIN lens 3 to the tip of the optical fiber 2.

At this time, the optical fiber 2 and the GRIN lens 3 are held by the fiber holder 20 and the lens holder 30, respectively (see fig. 1 a), the tip ends of the optical fiber and the GRIN lens are grounded, and the abutting surfaces of the two positioned between the pair of discharge electrodes 40 are fused by arc discharge (see fig. 1 b).

Fig. 1 shows an example in which a 4-core is used and the GRIN lens 3 is fusion-spliced to each optical fiber 2 whose tip end side is removed and drawn out. If necessary, a multi-core optical fiber core such as a 2-core, an 8-core, or a 12-core may be used, or a single-core optical fiber core may be used.

The GRIN lens 3 fused to the optical fiber 2 includes not only a refractive Index profile type lens without a coating layer but also a GI (Graded Index) fiber and the like, and is not particularly limited as long as the lens function is expressed by a refractive Index profile (Graded Index).

As the holders 20 and 30 for holding the optical fiber 2 and the GRIN lens 3, holders prepared according to the specifications of the optical fiber fusion-splicing apparatus may be used as they are, but they may be used with appropriate modifications as needed.

For example, in the example shown in fig. 1, as the lens holder 30 for holding the GRIN lenses 3, a configuration improved in such a manner that holding grooves having a V-shaped cross section or a "コ" shaped cross section or the like are provided in parallel at appropriate intervals and depths on the upper surface of the substrate 31 of the lens holder 30, and a plurality of (4 in the example shown in the drawing) GRIN lenses 3 can be positioned coaxially with the optical fibers 2 to be connected.

In the example shown in fig. 1, the lens holder 30 includes a substrate 31 and a holding plate 32 attached to the substrate 31 so as to be rotatable about one end thereof, and the GRIN lens 3 is held between the substrate 31 and the holding plate 32 by being pressed. The optical fiber holder 20 for holding the optical fiber 2 is similarly configured to include a base plate 21 and a holding plate 22 attached to the base plate 21 so as to be rotatable about one end thereof, and to press and hold the optical fiber 2 (optical fiber core) between the base plate 21 and the holding plate 22.

The holders 20 and 30 also function as positioning members for positioning the abutting surfaces of the optical fiber 2 and the GRIN lens 3, and when installed in the optical fiber fusion-splicing deviceThe end faces 20a, 30a facing each other are positioning faces. The end faces 20a, 30a are separated by a predetermined distance d₀When the holders 20 and 30 are installed in the optical fiber fusion-splicing device so as to face each other, the abutting surface between the optical fiber 2 and the GRIN lens 3 is positioned between the pair of discharge electrodes 40 (see fig. 1 (b)).

When the optical fiber 2 and the GRIN lens 3 are held by the fiber holder 20 and the lens holder 30, respectively, the length L from the end face 20a of the fiber holder 20 to the tip end of the optical fiber 2 is appropriately adjusted₂And a length L from the end face 30a of the lens holding frame 30 to the tip of the GRIN lens 3₃(see (a) and (b) of fig. 1) to enable the above-described positioning. In this case, it is preferable that the respective tips are aligned in advance as necessary so that the respective abutting surfaces of the optical fiber 2 and the GRIN lens 3 are perpendicular to the optical axis.

In this way, the optical fiber 2 held by the fiber holder 20 and the GRIN lens 3 held by the lens holder 30 are butted and fused at their distal ends, and then the holders 20 and 30 are removed from the optical fiber fusion-splicing apparatus.

When the holders 20 and 30 are removed from the optical fiber fusion-splicing device, the position at which the optical fiber 2 is held by the optical fiber holder 20 does not change.

On the other hand, the lens holder 30 moves the lens holder 30 in a direction away from the fiber holder 20 while relaxing the force of pressing the GRIN lens 3 (the holding force of the lens holder 30) by lifting the holding plate 32 from the upper surface of the substrate 31 or the like. At this time, since the GRIN lens 3 is welded to the optical fiber 2, the lens holder 30 can be moved without scattering and dropping the GRIN lens 3.

Then, the end face 20a of the optical fiber holder 20 and the end face 30a of the lens holder 30 are separated by a predetermined distance d (d)₀+ Δ d) is opposed to the GRIN lens 3, and the holding frames 20 and 30 are set in the cutting device (see fig. 1 (c) and 5).

A preferred cutting device used in the present embodiment will be described later.

Next, the GRIN lens 3 is cut into a rod shape at a position shown by a broken line in fig. 1 (d), thereby obtaining a lensed optical fiber 1 (see fig. 1 (e)).

When the GRIN lens 3 is cut, the length L from the fusion-spliced portion where the optical fiber 2 is fusion-spliced to the cutting position is appropriately adjusted in accordance with the refractive index distribution, the numerical aperture (numerical aperture), or the like of the GRIN lens 3 so that the GRIN lens 3 is cut at a length at which the working distance and the beam waist diameter (beam waist diameter) become desired values. Then, the moving distance Δ d of the lens holder 30 when the GRIN lens 3 is held again is set to be equal to the length L (Δ d — L), and the GRIN lens 3 is cut perpendicularly to the optical axis thereof by a length equal to the moving distance Δ d of the lens holder 30.

In this way, in the remaining GRIN lenses 3 held by the lens holder 30 after cutting, the length La (see fig. 1 (e)) from the end surface 30a of the lens holder 30 to the tip end of the GRIN lens 3 and the length L when the GRIN lens 3 is first held by the lens holder 30 are equal to each other₃(see fig. 1 (a)) are equal. This allows positioning when the optical fiber fusion-splicing device is installed as described above.

Therefore, the GRIN lens 3 remaining after cutting can be set in the optical fiber fusion-splicing device again in a state of being held by the lens holder 30, and can be butted and fused with the tip end of the newly prepared optical fiber 2.

As a result, according to the present embodiment, by repeating the steps from welding to cutting described above, it is possible to suppress wasteful consumption of the GRIN lens 3, and to manufacture the lensed optical fiber 1 with high productivity.

In the lensed optical fiber 1 manufactured in this manner, although not particularly shown, another GRIN lens having a different numerical aperture from that of the GRIN lens 3 may be further welded to the GRIN lens 3 welded to the tip thereof (see patent document 2), or a prism lens may be further welded to realize side emission (see patent document 3).

In the former case, for example, another GRIN lens having a different numerical aperture from that of the GRIN lens 3 may be held by the lens holder 30, and the steps from the fusion splicing to the cutting may be performed on the lensed optical fiber 1.

In the latter case, for example, the optical fiber for a prism lens is held by the lens holder 30, the steps from the fusion-splicing to the cutting are performed on the optical fiber 1 with a lens, and the tip of the optical fiber for a prism lens cut by a predetermined length is polished to form a tip inclined surface, thereby realizing the side light emission.

[ cutting device ]

Next, a cutting device according to the present embodiment will be explained.

Fig. 2 is a plan view showing an outline of a main part of the cutting apparatus according to the present embodiment, fig. 3 is a front view showing an outline of a main part of the cutting apparatus according to the present embodiment, and fig. 4 is a cross-sectional view a-a of fig. 2.

The cutting device according to the present embodiment is preferably used when the GRIN lens 3 butt-jointed and fused to the optical fiber 2 at the tip end thereof is cut by a predetermined length in the above-described method for manufacturing a lensed optical fiber, and an example of use thereof is shown in fig. 5.

As shown in these figures, the cutting apparatus 100 includes: an optical fiber holder placing unit 120 on which the optical fiber holder 20 holding the optical fiber 2 is placed; a lens holder mounting unit 130 on which the lens holder 30 for holding the GRIN lens 3 is mounted; and a cutting unit 140 disposed between the optical fiber holder mounting unit 120 and the lens holder mounting unit 130.

The cutting section 140 includes a cutting blade unit having a circular-edge-shaped cutting blade 141. As shown in fig. 5, the cutting unit 140 may have the following structure: the cutting blade 141 slides in a direction orthogonal to the GRIN lens 3, forms a cut at the cutting position of the GRIN lens 3, and then cuts the GRIN lens 3 by applying stress thereto.

Although not particularly shown, the cutting section 140 may have a configuration in which a clamping mechanism for gripping the GRIN lens 3 or the optical fiber 2 is provided near both sides of the cutting position. The cutting unit 140 may be configured to include a known cutting device for cutting an optical fiber.

The optical fiber holder placing unit 120 includes a positioning mechanism for positioning the placed optical fiber holder 20, and the lens holder placing unit 130 includes a positioning mechanism for positioning the placed lens holder 30.

In the present embodiment, as such a positioning mechanism, a positioning recess 121 that abuts against the end face 20a and the side face 20b of the optical fiber holder 20 to position the optical fiber holder 20 is engraved in the optical fiber holder placement section 120. Similarly, a positioning recess 131 that abuts against the end surface 30a and the side surface 30b of the lens holding frame 30 to position the lens holding frame 30 is engraved in the lens holding frame mounting portion 130.

These positioning recesses 121 and 131 are engraved so as to extend in series and have respective longitudinal ends located on the side on which the cutting portion 140 is disposed. Thereby, the end faces 20a, 30a of the retainers 20, 30 come into contact with the respective longitudinal ends of the positioning recesses 121, 131.

At this time, the positioning recesses 121 and 131 are engraved so that the end surfaces 20a and 30a of the retainers 20 and 30 face each other at a predetermined distance d (see fig. 5). Thus, in the method for manufacturing a lensed optical fiber described above, when the GRIN lens 3 is retained again, the moving distance Δ d of the lens holder 30 can be easily limited by simply bringing the end face 30a of the lens holder 30 into contact with the longitudinal end of the positioning recess 131.

When the length L of the GRIN lens to be cut is changed, spacers having a thickness corresponding to the changed length may be interposed between the longitudinal ends of the positioning concave portions 121 and the end faces 20a of the fiber holder 20, between the longitudinal ends of the positioning concave portions 131 and the end faces 30a of the lens holder 30, or between both. Thus, the moving distance Δ d of the lens holder 30 can be changed while maintaining the relationship of Δ d ═ L, and the distance d between the end surfaces 20a and 30a of the holders 20 and 30 can be maintained as d ═ d₀The relation of + Δ d.

The optical fiber holder mounting part 120 and the lens holder mounting part 130 provided with such a positioning mechanism may be configured by forming the positioning concave parts 121 and 131 in separate members and combining them, respectively, but in such a configuration, the positioning (horizontal adjustment or the like) of the mounting parts 120 and 130 is necessary. Therefore, if the positioning of the placement units 120 and 130 is insufficient, the optical fiber 2 and the GRIN lens 3 held by the holders 20 and 30 may be inclined, and the positioning accuracy may be deteriorated.

In order to avoid such a problem, it is preferable that the optical fiber holder mounting part 120 and the lens holder mounting part 130 are formed integrally, and the positioning is not necessary. For example, the optical fiber holder mounting portion 120 on which the positioning recess 121 is engraved and the lens holder mounting portion 130 on which the positioning recess 131 is engraved may be formed integrally by cutting one member using a metal plate or the like. Thus, the positioning of the fiber holder mounting part 120 and the lens holder mounting part 130 is not required, and the positioning accuracy can be further improved.

In the production of the lensed optical fiber 1 by cutting the GRIN lens 3 butt-jointed and fused to the optical fiber 2, the length L from the fusion-spliced portion where the optical fiber 2 is fused to the cutting position is not varied and the cut surface is perpendicular to the optical axis in order to improve the quality and the yield. In particular, in the above-described method for manufacturing a lensed optical fiber, when the plurality of GRIN lenses 3 remaining after cutting and the plurality of newly prepared optical fibers 2 are butted and fused at their tips, if there is variation in the end surface interval, for example, the welded portion becomes thick and thin, which causes problems such as deterioration in quality, variation in lens length, and failure to be accurately assembled to the ferrule.

According to the present embodiment, such a problem can be solved by increasing the positioning accuracy of the holders 20 and 30, but in order to achieve further improvement in quality and yield, it is preferable that the position of the cutting blade 141 can be appropriately adjusted with a high degree of freedom in accordance with the number of GRIN lenses 3 to be cut and the cutting position thereof.

For example, fig. 2 and 3 show the X axis, Y axis, and Z axis of the three-dimensional orthogonal coordinate system, and it is preferable that the cutting blade 141 be movable in the Z axis direction for adjusting the cutting position of the GRIN lens 3 and in the X axis direction orthogonal to the Z axis direction, and also movable in the Y axis direction for adjusting the depth of the cut formed in the GRIN lens 3.

In addition, the GRIN lens 3 to be cut may be inclined with respect to the z-axis due to individual differences of the holders 20 and 30. In consideration of this, it is preferable that the direction in which the cutting blade 141 slides be adjustable at a predetermined angle α on the XZ plane so that the direction in which the cutting blade 141 slides is always orthogonal to the optical axis of the GRIN lens 3.

In order to enable such position adjustment, for example, the cutting blade unit included in the cutting unit 140 may be supported by an XYZ rotation table or the like. By supporting the cutting blade unit on the XYZ rotation table, when adjusting the position of the cutting blade 141, the micrometer can perform the position adjustment of the XYZ axes and the angle adjustment on the XZ plane.

While the present invention has been described above by showing preferred embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

For example, in the cutting device 100 described above, as the positioning means provided in the optical fiber holder placement unit 120 and the lens holder placement unit 130, the positioning may be performed by locking engagement pins provided upright on the placement units 120 and 130 to engagement holes provided through the holders 20 and 30.

The contents of the documents described in the present specification and the contents of the japanese application specification, which is the basis of the paris priority of the present application, are incorporated herein by reference in their entirety.

Description of reference numerals:

1 lensed fiber

2 optical fiber

3 GRIN lens

20 optical fiber holder

20a end face

20b side surface

30 lens holder

30a end face

30b side surface

100 cutting device

120 optical fiber holder mounting part

121 location concave part (location mechanism)

130 lens holder mounting part

131 location concave part (location mechanism)

140 cutting part

141 cutting blade (cutting blade unit).