WO2002031554A1

WO2002031554A1 - Optical fiber array and method of manufacturing the array

Info

Publication number: WO2002031554A1
Application number: PCT/JP2001/008951
Authority: WO
Inventors: Akira Matsumoto; Masashi Fukuyama
Original assignee: Ngk Insulators,Ltd.
Priority date: 2000-10-12
Filing date: 2001-10-11
Publication date: 2002-04-18

Abstract

An optical fiber array (10), comprising a V-grooved substrate (16) having a V-groove part (7) with V-grooves (12) for disposing optical fiber bare parts (11) therein, a flat part (3) for disposing optical fiber covered parts (13) thereon, and a step part (1) for connecting the V-groove part (7) to the flat part (3), wherein, with the flat part (3) used as a reference plane (A), a height (H1) from the reference plane (A) to the center of the optical fiber covered parts (13) disposed on the flat part (3) is higher than a height (H2) from the reference plane (A) to the center of the optical fiber bare parts (11) disposed in the V-grooves (12), whereby a stress concentration to optical fibers can be prevented, the problems such as deterioration of characteristics become hard to occur, and a reliability can be increased.

Description

Description Optical fiber array and method for manufacturing the same

The present invention relates to an optical fiber array and a method for manufacturing the same. More specifically, the present invention relates to an optical fiber array used in the field of optical fiber communication and optical fiber sensors, in which optical fibers are aligned and fixed in V-grooves, and a method of manufacturing the same. Background art

In recent years, with the densification of optical fibers, the use of multi-core planar waveguides (PLCs) has been increasing. With the increase in the number of cores, PLCs are being developed to reduce the conventional standard waveguide pitch in order to avoid increasing the size of the waveguide element and further increase the density. . In line with the increase in the density of optical fibers and the reduction in waveguide pitch, optical fiber arrays for connecting optical fibers to other optical components, MT connectors for connecting optical fibers, etc. In this regard, the development of optical fiber pitches is also shrinking, and the challenge is how to maintain high reliability.

4 (a) and 4 (b) show an example of a conventional optical fiber array, FIG. 4 (a) is a side view, and FIG. 4 (b) is a CC cross section of FIG. 4 (a). See the cross-sectional view in the direction of the arrow.

The V-groove 42 is formed in the V-groove portion 8 of the V-groove substrate 46 of the optical fiber array 40, and the bare optical fiber portion 41 of the multi-core, for example, 16-core optical fiber 48 is formed. Each is arranged on the V groove 42. The upper lid substrate 44 is placed on the V-groove substrate 46 so as to sandwich the optical fiber bare portion 1 arranged in a line, and is fixed with an adhesive. The rear end portion 45 of the upper cover substrate is subjected to a curved surface processing so as not to damage the bare optical fiber portion 41. As shown in FIG. 4 (b), the bare optical fiber 41 is sandwiched between the V-groove substrate 46 and the upper lid substrate 44, and is fixed at three points. In such an optical fiber array 40 having the V-groove substrate 46 for mounting the bare optical fiber portion 41 in the V-groove 42 and aligning the same, the optical fiber coating portion is provided together with the bare optical fiber portion 41. In addition to the V-groove 42, there is a flat part 4 that is the lower part on which the optical fiber coating part 43 is mounted, and a step part 2 that connects the flat part 4 and the V-groove 8. are doing.

Such a conventional optical fiber array 40 has the following problems.

In the optical fiber array 40 shown in FIGS. 4 (a) and 4 (b), the rear end portion 49 of the V-groove substrate 46 is in a sharply standing state, and the stress of the adhesive is small. The portion where the stress fluctuates rapidly and the stress becomes large almost coincides with the edge 6 of the V groove 42.

(1) Since the fulcrum when the lateral optical fiber 48 is moved and the fulcrum in the upward and downward directions almost coincide, the edge of the bare optical fiber 41 and the edge of the V groove 42 Stress concentrated at the point P where the abutment 6 contacted, and the bare optical fiber 41 could be damaged.

Even if the scratches are small, if the optical fiber 48 is subjected to bending stress due to environmental changes (temperature and humidity fluctuations, etc.) due to long-term use, the damage will increase from the scratches and in the worst case. Include concerns about disconnections. In particular, when the step portion 2 has an angle of 90 degrees, the distance at which the edge 6 of the V groove 42 contacts the bare optical fiber portion 41 is short, and these stresses concentrate on this portion. The potential for problems was high.

In order to prevent the problem (1) from occurring, there has been proposed an optical fiber array using a V-groove substrate having an inclined step portion. In such an optical fiber array, the problem of the above (1) can be solved by forming the adhesive portion so as to gradually expand so as to have a clean stress distribution in which the generated stress gradually increases. I was trying to evacuate.

(2) However, if the inclination angle of the step portion is increased, the step portion becomes longer, and the amount of adhesive as a whole increases, so that this time there is a contradictory problem that the stress of the increased adhesive increases. You will have In addition, the problem that the edge 6 of the V-groove 42 stands sharp at the step portion 2 has been studied to be avoided by a method of forming a curved surface R by a rubber grindstone or partial puff polishing.

(3) However, since the depth of the V-groove 42 is about 100 to 150 m, the work is difficult, and the curved surface R cannot be partially removed. There was a problem that the machining quality was unstable.

The generation of scratches due to the edge 6 of the V-groove 42 may also occur during the manufacture of the optical fiber array 40 (when mounting the bare optical fiber portion 41 in the V-groove 42).

(4) When manufacturing the optical fiber array 40, an unnecessary load is applied downward (bending, crushing, etc.) at the rear (covering side) of the optical fiber 48, or the bare optical fiber 41 If it is shifted laterally (in a direction substantially perpendicular to the fiber arrangement direction), stress will be applied to the edge 6 of the V-groove 42, which may cause damage.

It should be noted that the stress on the bare optical fiber portion 41 at the edge 6 of the V-shaped groove 42 due to the lateral stress can be reduced even if the ribbon fiber is used, even if it is not shifted in the lateral direction during the manufacturing operation. There may be a case where the error is inevitably caused by a pitch error.

Furthermore, there were the following problems in the manufacturing process.

When assembling such an optical fiber array 40, the pitch between the fibers in the bare optical fiber portion 41 tends to shift, so that the bare optical fiber portion 41 cannot be arranged so as to be in contact with the V groove 42 from the beginning. First, the bare optical fiber portion 41 floats from the V groove 42. From this state, the bare optical fiber 41 is pressed by the upper lid substrate 44, so that the bare optical fiber 41 is arranged in the V groove 42. In particular, in the case of an optical fiber array having a large number of optical fibers or a half-pitch optical fiber array in which optical fibers are stacked in two layers, the optical fibers are within a predetermined range (within the width of the V groove) on the V groove. It is very difficult to recognize whether or not is located. For example, when observing the optical fiber array being assembled from the top, the lines that appear at the edges of the V-groove, the lines that appear at the bottom of the V-groove, and the lines that appear at the optical fiber itself are very narrow. Since many are arranged at intervals, it is difficult to recognize accurately. In addition, even if the force is observed at the front of the end face (opposite side of the flat part), the tip of the optical fiber and the end face of the V-groove will be at the time of assembly. Does not coincide with the longitudinal direction, and it is still difficult to accurately determine whether the optical fiber is located within a predetermined range on the V-groove.

(5) Therefore, as shown in FIG. 5, when the optical fiber bare portion 41 is not arranged directly above the V-groove 42, as shown in FIG. Even if the part 41 is pressed down, the bare optical fiber part 41 does not rest on the V-groove 42 and the bare optical fiber rests on the V-groove upper part 70 (the upper part of the V-groove 42). Could be fixed by the

(6) Even if the optical fiber finally fits in the V-groove 42, as shown in FIG. 7, the bare optical fiber 41 hits the opening edge 65 of the V-groove 42 and rubs the V-groove. 4 and there was a danger that the optical fiber bare part 41 would be excessively damaged.

FIG. 7 is a diagram showing an example of a conventional optical fiber array, and is a front view (an optical fiber bare portion side) showing a state in which an optical fiber fits into a V-groove during a manufacturing process. In FIG. 7, the left side shows a state before the bare optical fiber is pressed by the upper lid substrate, and the right side shows a state where the bare optical fiber is pressed by the upper lid substrate.

For the assembly of the optical fiber array, even with a 250 m pitch, place the φ125 im optical fiber on the V groove with an opening width of up to 250 m, and press down the V groove with the upper lid substrate , Need to be fixed. With multi-core optical fibers, this work is not easy to arrange, and even once the optical fibers are arranged, there are several meters of optical fibers (cables) to be attached to the optical fiber array. Even after the optical fiber is mounted on the V-groove substrate, the stress is applied by moving the optical fiber or the force is applied by the curl of the optical fiber itself. In the interim work or the work to press down on the upper lid substrate, etc., there is a case that the work slips out of the V groove.

This misalignment is caused by the position of the optical fiber jumping out of the V-groove when viewed from the front end face (the end face opposite to the flat surface of the V-groove). It is easy to occur because there is no right and left regulation in

In particular, in the case of ribbon fiber, the pitch is generally 250 m. In many cases, the pitch is wide, and there is a higher risk that the optical fiber will not be placed on the V-groove. For example, more specifically, if the pitch is about 260 m, the pitch between the first fiber and the twelfth fiber of the 12-fiber ribbon fiber is 260 × 11 = 2860 m. Since the V-groove of the optical fiber array is exactly 250 × 11 = 2750, the pitch is shifted by 2860-2750 = 110 m, making it difficult for the optical fiber to fit in the V-groove. Even if the entire repone fiber is accurately aligned, the position deviation of 110 2 = 55 occurs in the IV groove and the 12 V groove. Therefore, in the case of a repone fiber, there is a higher possibility that the optical fiber will come off the V-groove.

As described above, in an optical fiber array used to connect optical fiber arrays, optical connectors, or optical waveguide components, defects such as that optical fibers are not arranged in V-grooves during manufacturing. It does not cause damage to the optical fiber, and does not damage the optical fiber.Furthermore, even if various stresses are applied to the optical fiber due to environmental changes during and after the manufacturing process, the optical fiber is less likely to be damaged, and will not be damaged for a long time. Therefore, there has been a demand for a highly reliable optical fiber array that does not easily cause disconnection or increase in light attenuation. . DISCLOSURE OF THE INVENTION

The present invention has been made in view of the above-mentioned conventional problems (1) to (6), and has an object to prevent local stress concentration on an optical fiber. Provide an optical fiber array with high yield and low risk of problems such as deterioration of characteristics, and a method of manufacturing the optical fiber array, without performing complicated operations and without special handling of the manufactured product. Is to do.

The present inventors have conducted various studies on the structure and manufacturing method of an optical fiber array in order to achieve the above object, and as a result, it has been found that the following means can solve the conventional problems.

(A) First, in the state before the optical fiber is held down by the upper lid substrate and in the state where the optical fiber is held down by the upper lid substrate, barely bare the optical fiber from the rear end of the V-groove. It has been found that if the part is floating, the above problems (1) to (4) can be avoided. In other words, if the bare optical fiber does not hit the rear end of the V-groove, local stress concentration cannot be applied to the edge of the V-groove at the time of manufacturing or the manufactured product, and there is a concern that scratches may occur. Is dispelled. Such a state in which the bare fiber portion is at least slightly away from the rear end of the V-groove can be realized by appropriately setting the dimensions of the step portion of the optical fiber array.

(B) Next, in addition to the above (A), if the bare optical fiber is slightly inside the V-groove in the state before the bare optical fiber is pressed by the upper lid substrate,

It has been found that the problems (5) and (6) can be avoided. In other words, even if a part of the bottom of the bare optical fiber is below the upper surface of the opening of the V-groove, if it is shifted laterally (if there is no V-groove of the V-groove substrate as shown in Fig. 8) The bare optical fiber does not come into contact with the V-groove and the bare optical fiber hits the V-groove and the bare optical fiber hardly comes out of the V-groove. Even if the bare fiber goes out of the V-groove, only the bare optical fiber is placed on the top of the V-groove and bends, so it can be recognized by the naked eye, easy to find, and lowering the yield. Can be prevented. If at least the bare optical fiber is inside the V-groove and is held down by the upper lid substrate, the bare optical fiber is surely set in the V-groove, and in the process, the bare optical fiber becomes the opening edge of the V-groove. It does not hit and does not damage the optical fiber. Such a state can be realized by appropriately setting the dimensions of the step portion of the optical fiber array.

More specifically, the following means.

That is, according to the present invention, the following optical fiber array is provided. An optical fiber array according to the present invention includes a V-groove having a V-groove on which an optical fiber bare portion is disposed, a flat portion on which an optical fiber coating portion is disposed, and a step connecting the V-groove and the flat portion. An optical fiber array provided with a V-groove substrate, wherein a height HI from the reference plane A to the center of the optical fiber coating portion arranged in contact with the flat section is defined as a reference plane A, and An optical fiber array having a stepped portion that is higher than the height H2 to the center of the bare optical fiber disposed in the V-groove. Where height HI and height It is preferable that the difference from the height H2 is approximately 5 to 100 m.

In the present invention, the height H3 from the reference plane A to the top of the V-groove upper surface part of the V-groove part is defined as the reference plane A as the reference plane A, and the height H3 in the optical fiber coating part arranged on the plane part from the reference plane A is It is preferable to have a stepped portion that is higher than the height H4 up to the lower end of the optical fiber. Here, the lower end of the optical fiber in the optical fiber coating portion is the portion of the optical fiber portion in the coated optical fiber. Refers to the lower end. In addition, since most of the V-grooves are composed of horizontal surfaces, the height from the reference surface A to the V-groove upper surface is constant in any of the V-grooves. The height up to the top of the V-groove can be referred to as the height H3.

In the optical fiber array of the present invention, the length Z of the bare optical fiber that is not in contact with the V-groove is preferably about 20 mm or less.

Further, the optical fiber array of the present invention can be suitably used for a half-pitch optical fiber array in which optical fiber coating portions are laminated in two stages. Further, the optical fiber array is suitably used as an optical fiber array having an upper cover substrate for holding bare optical fibers arranged in the V-groove. The rear end of the upper lid substrate is preferably formed in an R shape.

Further, according to the present invention, the V-groove has a V-groove having a bare optical fiber portion, a flat portion having an optical fiber coating portion disposed thereon, and a step portion connecting the V-groove portion and the flat portion. What is claimed is: 1. A method for manufacturing an optical fiber array comprising: a V-groove substrate; and an upper cover substrate for holding the optical fiber bare portion disposed in the V-groove, wherein the bare optical fiber has a V-groove at a rear end of the V-groove. A method for manufacturing an optical fiber array, characterized in that the V-groove substrate and the upper lid substrate are solidified with an adhesive while not in contact with the V-groove, and the optical fiber bare portion is fixed and aligned in the V-groove. You. BRIEF DESCRIPTION OF THE FIGURES

1 (a) to 1 (d) are views showing an embodiment of an optical fiber array according to the present invention. FIG. 1 (a) is a side view, and FIG. 1 (b) is a view showing FIG. 1 (a). ) Is a cross-sectional view in the direction of arrow AA, and FIG. 1 (c) is a cross-sectional view in the direction of arrow BB in FIG. 1 (a). FIG. 1D is a perspective view of a single V-groove substrate constituting the optical fiber array. 2 (a) and 2 (b) are views showing another embodiment of the optical fiber array according to the present invention. FIG. 2 (a) is a side view, and FIG. 2 (b) is a front view ( Optical fiber coating part entrance side).

FIGS. 3 (a) and 3 (b) show still another embodiment of the optical fiber array according to the present invention. FIG. 3 (a) is a side view and FIG. 3 (b) is a front view. This is the figure (the optical fiber coating part entrance side).

4 (a) and 4 (b) are views showing an example of a conventional optical fiber array, FIG. 4 (a) is a side view, and FIG. 4 (b) is a cross-sectional arrow of FIG. 4 (a). It is sectional drawing of a viewing direction.

FIG. 5 is a diagram showing an example of a conventional optical fiber array, and is a front view (on the bare optical fiber side) in the middle of a manufacturing process.

FIG. 6 is a diagram showing an example of a conventional optical fiber array, and is a front view (the bare optical fiber side) in the middle of a manufacturing process.

FIG. 7 is a diagram showing an example of a conventional optical fiber array, and is a front view (an optical fiber bare portion side) showing a state in which an optical fiber fits into a V-groove during a manufacturing process. FIG. 8 is a view showing one embodiment of the optical fiber array according to the present invention, and is a front view (an optical fiber bare portion side) showing a state in which the optical fiber is accommodated in the V-groove during the manufacturing process.

9 (a) to 9 (e) are views showing an embodiment of the optical fiber array according to the present invention, FIG. 9 (a) is a side view, and FIG. 9 (e) is a state in the middle of a manufacturing process. FIG. 9B is a side view showing a state in which an optical fiber is placed on the V-groove substrate, and FIG. 9B is a cross-sectional view of one V-groove shown in FIG. FIG. 9C is a cross-sectional view of the other V-groove in FIG. 9E taken in the direction of the DD section, and FIG. 9D is a perspective view of a single V-groove substrate constituting the optical fiber array.

FIG. 10 is a view showing another embodiment of the optical fiber array according to the present invention, showing a state in the middle of the manufacturing process before mounting the upper cover substrate, and showing a state in which the optical fiber is mounted on the V-groove substrate. It is a side view. FIG. 11 is a view showing still another embodiment of the optical fiber array according to the present invention, which shows a state in the middle of the manufacturing process before mounting the upper lid substrate, and shows a state in which the optical fiber is mounted on the V-groove substrate. FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the optical fiber array and the method of manufacturing the same according to the present invention will be specifically described, but the present invention is not construed as being limited thereto, and is not limited to the scope of the present invention. In the above, various changes, modifications, and improvements can be made based on the knowledge of those skilled in the art.

An optical fiber array according to the present invention includes a V-groove having a V-groove in which an optical fiber bare portion is disposed, a flat portion in which an optical fiber coating portion is disposed, and a step connecting the V-groove and the flat portion. An optical fiber array with a V-groove substrate made of In the optical fiber array of the present invention, the plane portion is defined as a reference surface A (hereinafter, the reference surface A is also simply referred to as the reference surface), and the distance from the reference surface A to the center of the optical fiber covering portion arranged in contact with the flat portion is set. It is essential that the height H 1 has a step portion that is higher than the height H 2 from the reference plane A to the center of the optical fiber bare portion disposed in the V groove, and preferably, the step portion is The height H3 from the reference plane A to the top surface of the V-groove of the V-groove is higher than the height H4 from the reference plane A to the lower end of the optical fiber in the optical fiber coating placed on the flat surface. It is a difference part.

Here, first, the heights H1 to H4 will be described with reference to FIG. FIG. 10 is a view showing one embodiment of the optical fiber array according to the present invention, and is a side view showing a state in the middle of the manufacturing process before mounting the upper lid substrate. For example, in an optical fiber array 120 in which an optical fiber 108 is placed on a V-groove substrate 106, the height HI is determined by using the plane portion 104 of the V-groove substrate 106 as a reference plane A. It is the height from the reference plane A to the center CL of the optical fiber coating portion 103 arranged on the plane portion 104 (that is, the center of the coated optical fiber 101a). The height H4 is the height from the reference plane A to the lower end of the coated optical fiber 101a in the optical fiber coating 103 arranged on the plane portion 104. The heights H l and H 4 correspond to the optical fiber coating 103 arranged on the flat section 104. The height does not change even after the bare optical fiber portion 101 is pressed by the upper lid substrate.

The heights H2 and H3 shown below are the heights related to the V-groove portion 107 of the V-groove substrate 106, but the flat portion 104 remains the reference plane A. The height H3 is a height from the reference plane A to the top of the V-groove upper surface portion 100 of the V-groove portion 107. In the optical fiber array 120 shown in FIG. 10, the V-groove upper surface portion 100 is formed of a horizontal surface, and in any of the V-groove portions 107, the reference surface A is a flat surface portion 104. The height from the top surface of the V-groove 100 is constant, and the height H 3 can be said to be the height from the reference plane A to the top surface of the V-groove of the V-groove. When the upper surface of the groove is formed by an inclined surface, the height H3 is the height from the reference plane A to the uppermost portion of the upper surface of the V groove in the V groove. The V-groove upper surface portion 100 is the upper surface of the V-groove in the V-groove portion 107, and indicates the plane of the V-groove portion 107 when the V-groove is not formed. The height H3 does not change even after the bare optical fiber portion 101 is pressed by the upper lid substrate.

The height H2 is a height from the reference plane A to the center of the bare optical fiber portion 101 arranged in the V groove of the V groove portion 107. FIG. 10 shows a state in which the bare optical fiber portion 101 is not pressed by the upper lid substrate. At this time, the bare optical fiber portion 101 is floating from the V-groove, and By pressing the portion 101, the bare optical fiber portion 101 is placed in close contact with the V-groove. Accordingly, the height H2 changes after the bare optical fiber portion 101 is pressed by the upper lid substrate. The height H2 in the present invention is the height H2 after the optical fiber bare portion 101 is pressed by the upper cover substrate, not being manufactured.

In the following embodiments, only the relationship between the height H3 and the height H4 may be referred to, but in the present invention, the height H1 is higher than the height H2. It should be understood that this condition is fulfilled even if it is essential and is not indicated each time.

1 (a) to 1 (d) are diagrams showing an embodiment of an optical fiber array according to the present invention, and FIG. 1 (a) is a side view. Fig. 1 (b) is an AA cross section of Fig. 1 (a). FIG. 1 (c) is a cross-sectional view in the direction of the arrow, and FIG. 1 (c) is a cross-sectional view in the direction of the arrow BB in FIG. FIG. 1D is a perspective view of only the V-groove substrate. Note that the rear ends of the V-groove rear end, the upper lid substrate rear end, and the like refer to the ends closer to the optical fiber coating portion.

In FIG. 1A, the optical fiber array 10 includes an upper cover substrate 14 and a V-groove substrate 16, and an optical fiber 18 is inserted. A plurality of V-grooves 12 are formed in the V-groove portion 7 of the V-groove substrate 16, and the bare optical fiber portions 11 are arranged in each of the V-grooves 12 one by one. The V-groove substrate 16 has a flat portion 3 on which the optical fiber covering portion 13 is mounted. The V-groove portion 7 and the flat portion 3 are connected via the step portion 1 to form a V-groove substrate 16.

The V-groove rear end 19 refers to a portion where two surfaces of the V-groove 12 that draw a V-shape in a cross section meet the surface of the step portion 1 and the vicinity thereof. The height HI is defined as the center of the optical fiber coating 13 disposed on the plane 3 with the plane 3 as the reference plane A, that is, the center of the bare optical fiber stored in the optical fiber coating 13. The height H2 refers to the height from the plane portion 3 as the reference plane A to the center of the bare optical fiber portion 11 arranged on the V groove 12.

The upper lid substrate 14 is a member for holding the bare optical fiber 11 arranged in the V groove 12 of the V groove substrate 16.

The optical fiber array of the present invention is characterized in that the bare optical fiber 11 arranged in the V-groove 12 is not in contact with the V-groove 12 at the rear end 19 of the V-groove. This is because the height HI from the reference plane A to the center of the optical fiber coating 13 arranged on the plane part 3 is set on the V groove 12 with the plane part 3 of the V-groove substrate 16 as the reference plane A. This is realized by making the height to the center of the placed optical fiber bare portion 11 higher than H2. The difference between the height HI and the height H2 (hereinafter also referred to as ΔΗ) is generally about 5 to 100 m, so that the bending radius r of the bare optical fiber is not reduced, and 11 is preferable because it can be lifted from the V-groove 12 at the rear end 19 of the V-groove. If the length H is less than 5 m, it is difficult to obtain the actual effect that local stress concentration does not occur at the edge of the V-groove in the bare portion of the optical fiber, and ΔΗ is 100 / i. If it is larger than m, the bending radius r of the bare portion of the optical fiber naturally becomes large, resulting in an increase in loss, which is not preferable. More preferably, it is 20 to 50 m. '

The difference between the height HI and the height H2, that is, the effect of preventing stress concentration caused by ΔΗ also varies depending on the length Z of the bare optical fiber that is not in contact with the V-groove. The length Z of the bare optical fiber that is not in contact with the V-groove is the length of the bare optical fiber from the optical fiber coating that enters the V-groove and comes into contact with the V-groove. (Hereinafter also referred to as relaxation length Z). '

If the relaxation length Z is long, the bending radius r of the bare optical fiber increases, and the risk of loss increase due to bending is reduced.However, the bending is too gentle and the V-groove of the bare optical fiber at the V-groove terminal ends. △ becomes very small, and the above-described effect of preventing stress concentration is reduced. The terminus of the V-groove means a portion where the V-groove ends, that is, a portion adjacent to the step portion. Strictly speaking, when the length from the point at which the bare portion of the optical fiber placed on the V-groove leaves the V-groove to the end of the V-groove is, AU varies depending on the size of, but the reason described later In some cases, it is desirable to be within the range of 0.5 to 1.Omm, so it is preferable to increase the bending radius r of the bare part of the optical fiber in order to secure a certain amount of floating AU from the V groove. Absent. In other words, it is not preferable to make the relaxation length Z longer than a certain value. The relaxation length is preferably approximately 20 mm or less, more preferably 10 mm or less, and even more preferably 3 to 5 mm.

The lifting AU of the bare optical fiber from the V-groove at the end of the V-groove and the bending radius r of the bare optical fiber are expressed by the following equations. .

△ U = r— (r ² -AL ² ) ^1/2

r = ((Z / 2) ² + (ΔΗ / 2) ² ) / ΔΗ In the present invention, the condition that Δυ is the smallest is the difference between the height HI and the height H2 at the maximum relaxation length Ζ of 20 mm. The ΔΗ is the smallest at 5 m and the AL is 0.5 mm, where r is about 20 cm, and the lifting of the bare optical fiber from the V-groove at the V-groove end is about 0.007. m, but even in this case the optical fiber Since the bare part is not pressed against the edge of the V-groove, stress concentration can be avoided, and the bare part of the optical fiber is less likely to be scratched.

On the other hand, if the relaxation length Z is long, the amount of the adhesive increases, and the stress exerted on the entire optical fiber by the adhesive increases. Therefore, it is not preferable that the relaxation length Z is long for this reason.

Further, in the present invention, the rear end 15 of the upper lid substrate is provided with the V-groove 1 of the V-groove substrate 16 so that the bare optical fiber 11 does not come into contact with the V-groove 12 at the rear end 19 of the V-groove. It is also characterized by being positioned above 2.

In such an optical fiber array 10, as shown in FIG. 1 (a), the height HI is higher than the height H 2, so that the bare optical fiber 11 comes out of the optical fiber coating 13. As a result, it is mounted in the V-groove 12 without contacting the rear end 19 of the V-groove. The cross-sectional view at the rear end 19 of the V-groove is in the state shown in Fig. 1 (c), and the bare optical fiber 11 is not in contact with the edge 5 of the V-groove 12. The conventional problem, that is, the edge 5 of the V-shaped groove 12 does not damage the bare optical fiber 11. For example, even if the adhesive stress is concentrated on the optical fiber due to an environmental change, or the optical fiber is displaced, the bare optical fiber portion 11 is not damaged by the edge 5 of the V groove 12.

Also, when the rear end portion 15 of the upper lid substrate is located on the V-groove and is preferably formed as shown in FIG. 1A, that is, when the optical fiber is bare, Even if a stress that causes the portion 11 to bend upward is generated, no scratch is generated. Furthermore, the periphery of the bare optical fiber 11 is covered with an adhesive in a state where the floating ΔU of the bare optical fiber from the V-groove is secured at the end of the V-groove. At the end 19, more specifically, at the edge 5 of the V-groove 12, stress concentration on the bare optical fiber 11 cannot occur, resulting in a highly reliable optical fiber array 10. For example, when fixing the upper lid substrate and the V-groove substrate using two types of adhesives, first place the bare optical fiber in the V-groove, then temporarily fix the upper lid substrate on the V-groove with a jig, The first adhesive is injected from the surface, the first adhesive is filled in the entire upper lid substrate, and then cured. Then, the second adhesive is applied between the upper lid substrate and the optical fiber coating portion storage substrate. Inject from the open section, and store the optical fiber coating section and the optical fiber coating section. Hardening is performed after the entire space is filled. At this time, if the first adhesive is stopped at the rear end of the upper lid substrate and the back is used as the second adhesive, the bare optical fiber is arranged on the V-groove. Since a closed space is formed between the lower part of the bare fiber and the V-groove, even if the second adhesive is filled toward the first adhesive, it is difficult for air to escape and remains as air bubbles. Therefore, it is necessary to fill and cure the first adhesive over the entire length of the V-groove before filling with the second adhesive. However, at this time, if the length ΔL from the point where the bare optical fiber disposed on the V-groove leaves the V-groove to the end of the V-groove is long, the inside of the plurality of V-grooves corresponding to the multi-core optical fiber is required. Since the flow rate of the first adhesive is different between the outside and the outside, the first adhesive that has flowed out of the outside V-groove often reaches the inside V-groove at the end of the V-groove, and the front end surface The V-groove is closed before the first adhesive that flows more, and bubbles remain here. To avoid this, as described above, is preferably in the range of 0.5 to 1.0 mm.

Also, at the time of manufacturing, if the cross-section shown in Fig. 1 (c), the allowable range for lateral displacement (due to errors in work and Ripon pitch) is large, and the stress in the downward direction can be reduced. The tolerance for scratches is reduced because tolerance is also created.

When applying to a half-pitch optical fiber array in which repone fibers are stacked in two stages, the settings of the lower-stage optical fibers are set as described above. In this way, both the lower and upper bare optical fibers are mounted in the V-groove without contacting the rear end of the V-groove, and the bare optical fiber disposed in the V-groove is connected to the V-groove at the rear end of the V-groove. Do not touch.

9 (a) to 9 (e) show another embodiment of the optical fiber array according to the present invention. FIG. 9 (a) is a side view, and FIG. 9 (e) is a view showing a state during the manufacturing process, in which an optical fiber is placed on a V-groove substrate. 9 (b) and 9 (c) are cross-sectional views taken along the line DD in FIG. 9 (e). FIG. 9D is a perspective view of only the V-groove substrate.

In FIG. 9A, an optical fiber array 80 includes an upper lid substrate 94 and a V-groove substrate 86, and an optical fiber 88 is inserted therein. A plurality of V-grooves 82 are formed in the V-groove portion 87 of the V-groove substrate 86, and each V-groove 82 has one optical fiber bare portion 81. Are arranged. The V-groove substrate 86 has a flat portion 84 on which the optical fiber coating portion 83 is mounted. The V-groove portion 87 and the flat portion 84 are connected via a step portion 92 to form a V-groove substrate 86.

The height H3 refers to the height of the V-groove portion 87 up to the V-groove upper surface portion 90 with the flat portion 84 as the reference plane A. The height H4 refers to the flat portion 84 as the reference surface A. The lower end 98 of the optical fiber covering portion 83 of the optical fiber covering portion 83 arranged on the flat portion 84, that is, the optical fiber covering portion

83 Refers to the height of the bare optical fiber stored in 3 to the lower end.

The upper lid substrate 94 is a member for holding the bare optical fiber 81 disposed in the V-groove 82 of the V-groove substrate 86.

In the optical fiber array 80, before the optical fiber bare portion 81 is pressed by the upper cover substrate as shown in FIG. 9 (e), the example shown in FIG. 9 (b) and FIG. 9 (c) The feature is that the bare optical fiber 81 is slightly inside the V-groove 82 as shown in FIG. The height H 3 from the reference plane A to the V-groove upper surface 90 of the V-groove part 87 is defined as the reference plane A with the plane part 84 of the V-groove substrate 86 as the reference plane A. The lower end of the optical fiber of the optical fiber coating 83 placed on the flat surface 84

Heights up to 98 are achieved by being higher than H4.

Since the height H3 is higher than the height H4, the V-groove can restrain the optical fiber, so that the optical fiber in the V-groove is hard to come off before pressing the bare optical fiber with the upper cover substrate, and Even if there is an optical fiber that is out of the V-groove, it is easy to find out, and the effect of preventing a decrease in the yield that occurs when the bare optical fiber is manufactured without being arranged in the V-groove can be prevented. Therefore, the bare optical fiber does not rest on the V-groove, but is fixed on the upper surface of the V-groove (the upper surface of the V-groove). It is possible to avoid such a problem that the bare portion of the optical fiber is damaged by hitting the bare portion.

Also, in a multi-core optical fiber, for example, in a 12-core optical fiber, one optical fiber fits in a V-groove, and when only one fiber does not fit in a V-groove, it fits in a V-groove. Since the optical fiber is restricted by the V-groove and it is difficult to go outside, move the entire optical fiber sideways so that the last optical fiber that does not enter the V-groove enters. Thus, all the optical fibers can be easily arranged in the V-groove. Such work may be performed at the tip of the bare optical fiber on the V-groove (the front end of the optical fiber array, that is, on the side opposite to the flat surface). Thereafter, the optical fiber is guided using the V-groove as a guide. What is necessary is just to move to a predetermined position. Since the tip of the optical fiber is removed by polishing, even if the tip (end of the optical fiber) of the optical fiber is damaged in the above-mentioned operation (movement to the side of the optical fiber), there is no problem as a product.

When applied to a half-pitch optical fiber array in which ripon fibers are stacked in two layers, the upper optical fiber is not in the V-groove before being pressed by the upper lid substrate, but the lower optical fiber is When the bare optical fiber 81 in the optical fiber array 80 is in the state of the bare optical fiber 81, the lower optical fiber acts as a guide for the upper optical fiber. Both optical fibers easily fit into the V-groove. Since the optical fiber is circular, there is no sharp edge like the opening edge of the V-groove, and even if the upper and lower stages of the optical fiber are rubbed against each other in the V-groove while rubbing, they can damage the optical fiber. Absent.

FIG. 11 shows still another embodiment of the optical fiber array according to the present invention. In FIG. 11, the optical fiber array 130 is in a manufacturing process and shows a state before the optical fibers are pressed by the upper cover substrate. The optical fiber array 80 is different from the optical fiber array 80 shown in FIGS. 9A to 9E in that the V-groove upper surface 110 of the V-groove 117 is inclined. In the optical fiber array 130, the V-groove is formed horizontally. As can be seen from Fig. 11, when viewed from the side, the deviation of the bare optical fiber portion 1 1 1 is prevented over the entire V-groove. However, if at least a part of the optical fiber bare part 111 is in the V-groove, in other words, from the flat part 111 which is the reference plane A to the groove upper part 110 The height H3 from the top to the top is higher than the height H4 from the reference plane A to the lower end of the optical fiber covering section 113 located on the plane section 114 that is the reference plane A. , The displacement of the bare optical fiber 1 1 1 can be prevented. Such an optical fiber array 130 is excellent in that the bare optical fiber portion 111 does not come into contact with the edge of the V-groove at the rear end of the V-groove, and is hardly damaged. Hereinafter, the optical fiber array of the present invention will be described in more detail based on the examples including the manufacturing method. It is important to note that the bare optical fiber has a V-groove at the rear end of the V-groove. In this state, the V-groove substrate and the upper lid substrate are solidified with an adhesive in a state where they are not in contact with each other, and the bare optical fiber portions are fixed and aligned in the V-grooves. Even if various stresses are applied to the optical fiber in the product, the probability that the optical fiber is damaged and breaks can be reduced.

In this embodiment, in order to accurately position the optical fiber coating portion, the step portion is formed in two steps, and in order to reduce the influence of the stress of the adhesive, the upper surface portion of the optical fiber bare portion is formed. Although an open form is adopted, it goes without saying that the present invention is not limited to these embodiments.

(Example 1)

As shown in FIGS. 2 (a) and 2 (b), an optical fiber array 20 having a half-pitch (12.7 × m) of 48 cores using two 24 core ribbons was produced.

The material, PLC quartz waveguide: a (thermal expansion coefficient at 5 X 1 0- ⁷ Bruno), the substrate because quartz or S i, low thermal expansion, and at a low cost available glass materials on the market there Pyrex (trade name: U-learning Co., thermal expansion coefficient:. 3 2 5 X 1 0- 7 / ° C) was used.

First, 48 cores × 5 groups of 240 cores V-grooves were ground on a 50 × 50 mm wafer by a micro grinder. The depth of the V-groove was set so that the upper end of the bare optical fiber 21 protruded 5 mm, so that the bare optical fiber 21 was in two-point contact with the V-groove.

A step groove orthogonal to the V groove was machined with a slicer. The flat surface before machining the V-groove in the V-groove shown in FIG. 2, that is, the V-groove upper surface 60 equivalent surface in the perspective view of only the V-groove substrate shown in FIG. The depth of the first step 22 from B is 0.14 mm, and the depth of the second step 28, that is, the vertical distance from the flat part 53 to the right is 0.17 mm. And At this time, the vertical distance from the reference plane B to the center of the bare optical fiber portion 21 arranged in the V-groove was 0.03 mm.

Next, an optical fiber covering part storage substrate 27 positioned at the second step part 28 is prepared, placed on the flat part 53 of the V-groove substrate 26, and accurately aligned in the lateral direction and adhered. Fixed. Next, using a die sintering machine, the length of the V-groove of the V-groove substrate 26 is 4 mm, the length of the flat portion 53 in the longitudinal direction is 3 mm, and the open portion 5 between the V-groove portion and the flat portion 53 is formed. Each chip was cut so that the length in the longitudinal direction of 5 was 5 mm, the width of the V-groove substrate 26 and the width of the optical fiber coating portion storage substrate 27 were 9 mm.

The width of the upper lid substrate 24 is set to 8.7 mm, which is 0.3 mm smaller than the width of the V-groove substrate 26, and the length of the upper lid substrate 24 is set so that the rear end of the upper lid substrate is positioned on the V-groove. The length was 3.5 mm, which was 0.5 mm smaller than the length of the V groove. That is, the length in the horizontal direction from the rearmost end of the rear end of the V-groove to the rearmost end of the rear end of the upper lid substrate was set to 0.5 mm.

Next, the optical fiber array 20 was assembled.

First, the lower part of the optical fiber coating part (also called a tape fiber) 23 b with a thickness of 3 mm was formed by bonding and fixing the V-groove substrate 26 and the optical fiber coating part storage substrate 27. Along the wall on one side of the optical fiber coating portion storage groove 25 (the space inside the optical fiber coating portion storage substrate 27), the tape fiber 23 b was inserted into the second step portion 28 until the tape fiber 23 b hit. Here, if the relative positions of the optical fiber sheath storage groove 25 and the V groove are aligned, each bare optical fiber (also called a bare fiber) 21 of the tape fiber 23 b is placed on each V groove. Is done. In this state, the tape fiber 23b was temporarily fixed outside the optical fiber array 20. At this time, the bare fibers 21 are arranged every other V-groove.

Here, the height HI from the flat portion 53 to the center of the lower tape fiber 23b of 0.3 mm in thickness is 0.3 no 2 = 0.15 mm. The height H2 from the flat portion 53 to the center of the bare optical fiber 21 disposed on the V-groove is 0.170.03 = 0.14 mm. That is, the height H1 is 10 m higher than the height H2. Therefore, the bare optical fiber 21 can be mounted on the V-groove at the rear end of the V-groove without making contact with the V-groove. "

Next, the upper tape fiber 23 a having a thickness of 0.3 mm is inserted along the wall on one side of the optical fiber coating portion storage groove 25 on the opposite side to the above to the same position as the lower one, The tape fiber 23a was temporarily fixed. As a result, in the same way as above, The bare fiber 21 is placed in the first place.

Next, the upper lid substrate 24 was set on the upper part of the V groove, and a load was applied by a jig. If the upper lid substrate 24 is pressed against the side wall of the optical fiber coating portion storage substrate 27, the position in the longitudinal direction and the parallelism are naturally determined.

Next, as shown below, the upper lid substrate 24, the optical fiber coating portion storage substrate 27, and the V-groove substrate 26 were fixed using two types of adhesives.

First, after placing the bare optical fiber 21 in the V-groove, the upper lid substrate 24 is temporarily fixed on the V-groove with a jig, the first adhesive is injected from the front end face, and the entire upper lid substrate 24 is After one adhesive was filled, it was cured. Next, a second adhesive is injected from an open portion between the upper lid substrate 24 and the optical fiber coating portion storage substrate 27, and the optical fiber coating portion storage substrate 27 and the optical fiber coating portion 23a Hardening was performed after the entire space was filled, including the gap with 3b. Thereafter, the end face was polished to complete the optical fiber array 20. The final dimensions are as shown in Fig. 2 (a) and Fig. 2 (b).

(Example 2)

A standard optical fiber array 30 shown in FIGS. 3 (a) and 3 (b) was produced. The second embodiment differs from the first embodiment in that a single-stage optical fiber is used instead of two-stage optical fibers.

'Hereafter, the description will be made focusing on the differences from the first embodiment.

In the case of one stage, the bending radius of the optical fiber does not become small, so the distance (corresponding to the open portion 56) until the bare fiber 31 coming out of the tape fiber 33 fits in the V groove is set in two stages. In general, the pitch error of the tape fiber 33 is about 0.1 mm, so in order to alleviate the error of 0.05 mm on each side, the actual value is 3 mm. did. As a result, the bending radius of the optical fiber was not too small, and good characteristics were obtained.

In the second embodiment, an optical fiber coating unit receiving substrate 37 corresponding to the flat portion 54 of the V-groove substrate 36 is prepared, placed on the flat portion 54 of the V-groove substrate 36, They were glued and fixed in the correct length direction. Next, the dimensions shown in FIGS. 3 (a) and 3 (b) are obtained by using a die sintering machine, for example, setting the width of the V-groove substrate 36 to 7.0 mm. Each chip was cut.

Further, as in the first embodiment, the width of the upper lid substrate 34 is set to 6.7 mm, which is 0.3 mm smaller than the width of the V-groove substrate 36, and the length of the upper lid substrate 34 is It was 3.5 mm, which is 0.5 mm smaller than the length of the V-groove so as to be positioned. That is, the length in the horizontal direction from the rearmost end of the rear end of the V-groove to the rearmost end of the rear end of the upper lid substrate was set to 0.5 mm in the horizontal direction.

Next, the optical fiber array was assembled.

Assembling is performed by attaching a 3 mm-thick tape fiber 33 to the V-groove substrate 36 and the optical fiber coating portion storage substrate 37 by bonding and fixing the optical fiber coating portion storage groove 35 (the space inside the optical fiber coating portion storage substrate 37). Along the wall until the second step 38 was reached. In this state, the tape fiber 33 was temporarily fixed outside the optical fiber array 30.

Here, the height HI from the flat portion 54 to the center of the 0.3 mm thick tape fiber 33 is 0.3 / 2 = 0.15 mm. The height H2 from the flat portion 54 to the bare optical fiber portion 31 arranged on the V-groove is 0.17-0.03 = 0.14 mm as in the first embodiment. That is, the height H1 is 10 m higher than the height H2. Therefore, the bare optical fiber 31 can be mounted on the V-groove at the rear end of the V-groove without making contact with the V-groove.

Next, the upper lid substrate 34, the optical fiber coating portion storage substrate 37, and the V-groove substrate 36 were fixed using two types of adhesives as described below.

First, after placing the bare optical fiber portion 31 in the V-groove, the upper lid substrate 34 is temporarily fixed on the V-groove with a jig, the first adhesive is injected from the front end face, and the first adhesive is applied to the entire upper lid substrate 34. After the agent was filled, it was cured. Next, a second adhesive is injected from an open portion between the upper lid substrate 34 and the optical fiber coating portion storage substrate 37, including a gap between the optical fiber coating portion storage substrate 37 and the optical fiber coating portion 33, After curing was performed after filling the entirety, the end face was polished to complete the optical fiber array 30. The final dimensions are as shown in Figs. 3 (a) and 3 (b).

(Example 3) An optical fiber array was produced in the same manner as in Example 1 except that the upper cover substrate was not used.

The difference from the first embodiment in the assembling is that after placing the bare optical fiber on the V-groove substrate, a Teflon fiber holding substrate is used instead of the upper cover substrate. The fiber holding substrate and jig were used to fix the bare optical fiber while holding it down, and the adhesive was cured. Since the fiber holding substrate is made of fluororesin such as tetrafluoroethylene, it easily peels off from the adhesive and comes off the V-groove substrate. The fiber holding substrate was installed so as to be located on the front end side at the rear end of the V-groove of the V-groove substrate, and the bare optical fiber was lifted off the V-groove at the end of the V-groove. The adhesive was cured in this state.

In addition, in the step of polishing the last end face, if there is no upper cover substrate, the fixed optical fiber bare part may be damaged, so the dummy fiber holding board is installed again and fixed, and then the end face polishing is performed. Got the product. Industrial applicability

As described above, according to the present invention, it is possible to provide an optical fiber array which prevents stress concentration on an optical fiber, hardly causes problems such as characteristic deterioration, and has excellent reliability, and a method for manufacturing the same.

Claims

The scope of the claims

1. A V-groove substrate including a V-groove having a V-groove in which an optical fiber bare portion is disposed, a flat portion in which an optical fiber coating portion is disposed, and a step portion connecting the V-groove and the flat portion. The optical fiber array provided

The height H1 from the reference surface A to the center of the optical fiber coating portion disposed in contact with the flat portion with the flat portion as the reference surface A is a light beam arranged from the reference surface A to the V-groove. An optical fiber array comprising the stepped portion having a height higher than H2 to a center of a bare fiber portion.

2. The optical fiber array according to claim 1, wherein a difference between the height HI and the height H2 is approximately 5 to 100 x m.

3. The height H3 from the reference plane A to the top of the V-groove upper surface of the V-groove is the height from the reference plane A to the lower end of the optical fiber in the optical fiber coating disposed on the flat surface. 3. The optical fiber array according to claim 1, comprising the stepped portion having a height higher than H4.

4. The optical fiber array according to any one of claims 1 to 3, wherein the length Z of the bare optical fiber that is not in contact with the V groove is approximately 2 Omm or less.

5. The optical fiber array according to any one of claims 1 to 4, wherein the optical fiber array is used for a half-pitch optical fiber array in which optical fiber coating portions are stacked in two stages.

6. The optical fiber array according to any one of claims 1 to 5, further comprising an upper cover substrate for holding the bare optical fiber disposed in the V groove.

7. The optical fiber array according to claim 6, wherein a rear end of the upper cover substrate is formed in an R shape.

8. A V-groove substrate having a V-groove having a V-groove for disposing the bare optical fiber portion, a flat portion for disposing the optical fiber coating portion, and a step portion connecting the V-groove portion and the flat portion. A method for manufacturing an optical fiber array comprising: an upper lid substrate for holding a bare optical fin in the V-groove;

The bare optical fiber is not in contact with the V groove at the rear end of the V groove A method for manufacturing an optical fiber array, comprising: solidifying the V-groove substrate and the upper lid substrate with an adhesive; and fixing and aligning the bare optical fiber portion in the V-groove.