JPH06118267A - Reflection preventing structure for light switch - Google Patents

Abstract

PURPOSE:To surmount the difficulty to uniformly coat a reflection preventing coat on end faces of many optical fibers in a light switch. CONSTITUTION:A reflection preventing coat 11 is applied on the end face 1a of an optical fiber 1 on the master side inserted into an inner ferrule 8, a convex lens 10 applied with the reflection preventing coat 11 on both faces is arranged in front of the optical fiber 1, and the convex lens 10 is held by an outer ferrule 9. A glass plate 14 applied with the reflection preventing coat 11 on the light incidence face is closely stuck with an adhesive 13 to the end faces of many optical fibers 2 coupled with V-grooves 5 of a substrate 4. The end face 1a of the optical fiber 1 on the master side and the end faces 2a of many optical fibers 2 are arranged at the interval to keep the image forming relation via the convex lens 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection structure in an optical switch.

[0002]

2. Description of the Related Art In a mechanical optical switch that switches a master side optical fiber and a plurality of side optical fibers in a direction orthogonal to their optical axes to switch or cut off an optical path, one or more master side optical fibers are used. The end faces of a plurality of optical fibers and the end faces of a large number of optical fibers arranged at equal intervals are selectively butted to optically couple with each other.

In this optical switch, matching oil may be used on the end faces of the optical fibers in order to prevent end face reflection between the master side optical fibers and the multiple side optical fibers. This matching oil is generally used with the end face of the optical fiber immersed in the oil, but since the optical switch is driven to perform switching operation, it is technically difficult to hermetically seal the matching oil. Is likely to occur, and the matching oil is difficult to maintain due to aging. Therefore, the matching oil cannot satisfy the conditions of 100,000 switching operations or 10-year durability required for the optical switch.

On the other hand, it has been attempted to apply an antireflection coat (AR coat) to the end face of the optical fiber as an alternative to the matching oil. This antireflection coat is applied to the end face of the optical fiber and is not sealed and sealed like matching oil. Therefore, it is convenient for an optical switch or the like. However, it is difficult to apply the antireflection coating uniformly to the end faces of a large number of optical fibers arranged on the same plane, and its use in an optical switch has not yet been technically established.

To explain this with reference to FIG. 7, the tip of the optical fiber 1 on the master side is inserted into the ferrule 3, and the optical fibers 2 on the multiple side are respectively inserted into a plurality of V grooves 5 formed in the substrate 4. It is fitted with each optical fiber 2
Are maintained with the spacing accuracy maintained. The optical fibers 2 on the multiple side may be held by a single substrate 4, but when there are many optical paths to switch and the number of optical fibers 2 is large, the substrates 4 are stacked in multiple stages as shown in the figure. The optical fiber 2 of the uppermost substrate 4 is pressed by the pressing plate 6 to form the fiber holder 7 as a whole.

[0006]

In many optical switches, the front end face 7a of the fiber holder 7 is 20 mm.
It becomes a flat surface of (width) × 30 mm (height). But,
It is technically very difficult to uniformly apply the antireflection coat to each end face 2a of the plurality of optical fibers 2 arranged on the front end face 7a of the fiber holder 7. That is, in order to apply the antireflection coating to the end surface of the optical fiber 2, the fiber holder 7 is put in a vacuum container (not shown) and vacuum vapor deposition is performed. Because the optical fiber 2 of the book is stretched, its handling is difficult,
Particularly, since the long optical fiber 2 penetrates the wall of the vacuum container and is guided to the outside, there is a problem that it is difficult to maintain a vacuum inside the container.

An object of the present invention is to provide an antireflection structure in an optical switch that solves the above problems.

[0008]

An antireflection structure in an optical switch according to the present invention provides an optical connection between end faces of an optical fiber on a master side and an optical fiber on a plurality of sides, and an optical connection on the master side and a plurality of sides. In an optical switch that switches by moving the fiber in the direction orthogonal to its optical axis,
It is arranged on the front side of the master side optical fiber, and has a lens with an antireflection coating on at least the front surface, and a glass plate that is in close contact with the end faces of the optical fibers on the multiple side and has an antireflection coating on the light incident surface. The end faces of the optical fibers on the master side and the optical fibers on the multiple side are provided at intervals so as to maintain an image forming relationship.

A convex lens, a grain lens, a plano-convex lens or the like can be used as the above lens.

Alternatively, the optical fiber on the master side may be fitted in the V-shaped groove of the substrate and the grain fiber having at least the front surface coated with antireflection as the lens may be fitted to optically couple the both.

Further, when there are a plurality of optical fibers on the master side, the optical fibers are fitted into a plurality of V grooves of the substrate,
At least the front surface of the substrate may be provided with a lens array having an antireflection coating.

[0012]

According to the structure of the present invention, the light emitted from the optical fiber on the master side passes through the lens and further passes through the glass plate to form an image on the end faces of the optical fibers on the multiple side. At this time, since the antireflection coating is uniformly applied to the lens and the glass plate in advance before assembling them into the optical switch, there is no connection loss or variation in loss, and smooth switching operation is performed. .

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of the optical switch according to the first embodiment, in which the fiber end faces 1a and 2a of the master side optical fiber 1 and the multiple side optical fiber 2 are provided so as to face each other. The tip of the optical fiber 1 on the master side is inserted into the inner ferrule 8, and the inner ferrule 8 is further inserted into the outer ferrule 9. The tip of the outer ferrule 9 projects more than the tip of the inner ferrule 8.

A convex lens 10 is arranged at the tip opening edge 9a of the outer ferrule 9, and the end face 1 of the optical fiber 1 is arranged.
It is provided at a constant distance from a. Further, both surfaces of the convex lens 10 are coated with the antireflection coating 11, and the end surface 1 a of the optical fiber 1 is also coated with the antireflection coating 11.

On the other hand, the optical fibers 2 on the plural sides are fitted in the V-grooves 5 of the substrate 4 with their end faces 2a aligned flush with each other, and the optical fibers 2 are arranged with an equal interval P therebetween. The optical fiber array 12 is configured as a whole. Each optical fiber 2
Adhesive 13 is applied to the end surface 2a of the transparent glass plate 13 having a predetermined thickness L on the end surface 4a of the substrate 4 via the adhesive 13 and a transparent glass plate 13 having an antireflection coating 11 on the front surface. It is closely attached. The glass plate 13 is provided in a size capable of covering a large number of optical fibers 2.

In the above structure, the end surface 1a of the optical fiber 1 on the master side and the end surface 2a of the optical fibers 2 of the main body are provided.
Are arranged at intervals such that they form an image via the convex lens 10. Therefore, according to this optical switch, the light emitted from the optical fiber 1 on the master side is not reflected by the convex lens 1.
After passing through 0, and further through the glass plate 14, an image is formed on the end surface 2a of the optical fiber 2 on the multiple side.

In the optical switch of the first embodiment, instead of applying the antireflection coating to the end faces 2a of the optical fibers 2 on the multiple side as in the prior art, the front face of the glass plate 14 adhered to the end faces 2a is replaced with the antireflection coat. An antireflection coat 11 is applied. The antireflection coating 11 is applied to the glass plate 14 by placing the glass plate 14 in a vacuum container (not shown) in the state of the glass plate alone before incorporating it into the optical switch. It is easy and can maintain a high vacuum inside the vacuum container, and evenly coats the front surface of the glass plate 14 with an antireflection coating 1.
1 can be applied.

Since the master side optical fiber 1 is much easier to handle than the multiple side optical fiber 2, the antireflection coating 1 is formed on the end face 1a of the optical fiber.
There is no problem with applying 1 uniformly.

Similarly to the above, the convex lens 10 is also applied to the convex lens as a single lens in a vacuum container before being incorporated into the optical switch. The reason why the convex lens 10 is provided is as follows. That is, as shown in FIG.
By using, the end face 1a of the optical fiber 1 on the master side and the end face 2a of the optical fibers 2 on the multiple side are arranged apart from each other, and light is diffused between them. Therefore, in the first embodiment, the light diffused by the convex lens 10 is converged and the two fibers are optically coupled.

In the optical switch of the first embodiment, the antireflection coating 11 is applied to the end surface 1a of the optical fiber 1 on the master side, both surfaces of the convex lens 10 and the surface of the glass plate 14, respectively. Therefore, the end face of the light is not reflected between the master-side optical fiber 1 and the multiple-side optical fiber 2, and the connection loss can be suppressed.

In the optical switch of the first embodiment,
Since a sealed space 15 is formed between the end surface 1a of the optical fiber 1 and the convex lens 10, the space 15 may be filled with matching silicone oil. In this case, the antireflection coating 11 on the end surface of the optical fiber and the antireflection coating 11 on one surface of the convex lens 10 need not be applied.

Next, an optical switch according to the second embodiment will be described with reference to FIG. In the optical switch of the second embodiment,
Instead of the convex lens 10 of the optical switch of the first embodiment, a grain (GRIN) lens 16 having antireflection coatings 11 on both end faces is used. Other configurations are similar to those of the first embodiment. Also in the optical switch of the second embodiment, the end face 1a of the optical fiber 1 on the master side and the end face 2a of the optical fiber 2 on the multiple side are in an image forming relationship via the grain lens 16, and the optical fiber on the master side is formed. The optical path can be switched without moving 1 to cause end face reflection.

An optical switch according to the third embodiment will be described with reference to FIG. In the optical switch of the third embodiment, instead of the convex lens 10 of the optical switch of the first embodiment, a plano-convex lens 17 having a flat base end surface and a convex front end surface is used. An antireflection coating 11 is applied to the base end surface and the front end surface of the plano-convex lens 17. Other configurations are similar to those of the first embodiment. Also in the optical switch of the third embodiment, the end face 1a of the master-side optical fiber 1 and the end face 2a of the multiple-side optical fiber 2 are in a coupling relationship via the plano-convex lens 17, and the master-side optical fiber 1 The optical path can be switched without moving the and causing reflection.

An optical switch according to the fourth embodiment will be described with reference to FIG. In the optical switch of the fourth embodiment, a grain fiber 18 is used instead of the convex lens 10 of the optical switch of the first embodiment. This grain fiber 18
The master-side optical fiber 1 and the master-side optical fiber 1 are fitted into large and small V-grooves 20 and 21 formed continuously on the substrate 19.
The optical fiber 1 on the master side and the grain fiber 18 are aligned within 0 and 21. The antireflection coating 11 is also applied to both end surfaces of the grain fiber 18. Other configurations are similar to those of the first embodiment.

Also in the optical switch of the third embodiment, the end face 1a of the optical fiber 1 on the master side and the end faces 2a of the optical fibers 2 on the multiple side are in an image forming relationship via the grain fiber 18, and together with the substrate 19. Master side optical fiber 1
The optical path can be switched without moving the and causing the end face reflection.

An optical switch according to the fifth embodiment will be described with reference to FIG. The optical switch according to the fifth embodiment has a plurality of master-side optical fibers 1 unlike the first to fourth embodiments. In the optical switch according to the fifth embodiment,
It is necessary to arrange a plurality of optical fibers 1 on the master side at equal intervals. Therefore, each optical fiber 1 on the master side has a plurality of large and small V grooves 20 formed on the substrate 19 at equal pitches.
It is fitted in 21 small grooves.

The large grooves of the V-shaped grooves 20, 21 of the substrate 19 described above are fitted with the grain fibers 18 having antireflection coating 11 applied to both end surfaces thereof at a predetermined distance from the end surfaces of the optical fiber 1. There is. In addition, the end surface 1a of the optical fiber 1
A rod-shaped glass component 22 is fitted between the optical fiber 1 and the grain fiber 18, and the rod-shaped glass component 22 is adhered to the end face 1 a of the optical fiber 1 with the adhesive 13 in the V-grooves 20 and 21. The optical fiber 1, the glass component 22, and the grain fiber 18 are aligned. Fifth
In the optical switch of the embodiment, the optical fiber 2 on the multiple side
The support structure of is the same as that of the first to fourth embodiments.

Also in the optical switch of the fifth embodiment, the end face 1a of the optical fiber 1 on the master side and the end faces 2a of the optical fibers 2 on the multiple side are in an image forming relationship via the grain fiber 18, and the master side is formed. The optical path can be switched without moving the optical fiber 1 and causing the end face reflection.

An optical switch according to the sixth embodiment will be described with reference to FIG. In this optical switch, as in the optical switch of the fifth embodiment, the plurality of optical fibers 1 on the master side are fitted in V grooves 20 formed on the substrate 19 with their end faces aligned. The optical switch of the sixth embodiment differs from that of the fifth embodiment in that the lens array 23 is closely attached to the end face of the substrate 19 via the adhesive 13. This lens array 23 is
A large number of lenses 23b are embedded in the front surface of the glass plate 23a at equal intervals, and the respective lenses 23b are provided at the arrangement intervals whose centers are aligned with the center line of each optical fiber 1.
Further, the antireflection coating 11 is formed on the front surface of the lens array 23.
Has been applied.

In the optical switch of the sixth embodiment, the support structure for the optical fibers 2 on the multiple side is the same as in the first to fourth embodiments.

Also in the optical switch of the sixth embodiment, the end face 1a of the optical fiber 1 on the master side and the end faces 2a of the optical fibers 2 on the multiple side are in an image-forming relationship via the lens array 23, and the light on the master side is formed. The optical path can be switched without moving the fiber 1 to cause end face reflection.

In addition to the above embodiment, the end faces 2a of the master-side optical fiber 1 and the multi-sided optical fiber 2 are arranged in an image-forming relationship via a lens, and the multi-sided optical fiber 2 is arranged. The structure of the lens, the supporting structure of the lens and the optical fiber 1, and the like may be appropriately changed as long as the glass plate 14 is in close contact with the end surface 2a of the above.

[0034]

According to the antireflection structure of the optical switch of the present invention, a glass plate is used as an optical switch component which can be easily applied with an antireflection coat, and the light incidence surface of the glass plate is provided with the antireflection coat. Moreover, by adhering this glass plate to the end faces of the optical fibers on the multiple side, it was possible to overcome the technical difficulty of uniformly applying the antireflection coating to the end faces of the optical fibers on the multiple side as in the conventional case. . Also, with the use of this glass plate, the problem of light diffusion between the optical fibers facing each other at a distance is that the end faces of the optical fibers on the master side and the multiple side are passed through the lens with the antireflection coating on the surface. The problem was solved by arranging them at intervals that maintain the imaging relationship.

As described above, according to the present invention, the technical difficulty of using the optical switch antireflection coat can be overcome, and an optical switch with a small connection loss can be provided.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view of a first embodiment of the present invention.

FIG. 2 is a partially cutaway plan view of a second embodiment of the present invention.

FIG. 3 is a partially cutaway plan view of a third embodiment of the present invention.

4A is a partially cutaway plan view of a fourth embodiment of the present invention, and FIG. 4B is a sectional view taken along the line AA of FIG. 4A.

FIG. 5 is a partially cutaway plan view of a fifth embodiment of the present invention.

FIG. 6 is a partially cutaway plan view of a sixth embodiment of the present invention.

FIG. 7 is a perspective view of a conventional optical switch.

[Explanation of symbols]

1 ... Optical fiber, 2 ... Optical fiber, 4 ... Substrate, 5 ... V
Grooves, 10 ... Convex lens, 11 ... Antireflection coating, 14 ... Glass plate, 16 ... Grain lens, 17 ... Plano-convex lens, 1
8 ... Grain fiber, 23 ... Lens array.

Claims (6)

[Claims] 1. An optical switch for switching optical connection between end faces of a master-side optical fiber and a multi-sided optical fiber by moving the master-side and multi-sided optical fibers in a direction orthogonal to an optical axis thereof. It is arranged on the front side of the master side optical fiber, and has a lens with an antireflection coating on at least the front surface, and a glass plate that is in close contact with the end faces of the optical fibers on the multiple side and has an antireflection coating on the light incident surface. , An anti-reflection structure in an optical switch provided at an interval in which the end faces of the optical fibers on the master side and the optical fibers on the multiple side maintain an image forming relationship. 2. The antireflection structure for an optical switch according to claim 1, wherein the lens is a convex lens. 3. The antireflection structure for an optical switch according to claim 1, wherein the lens is a grain lens. 4. The lens is a plano-convex lens.
An antireflection structure in the optical switch described. 5. The light according to claim 1, wherein the master-side optical fiber and a grain fiber having an antireflection coating on at least the front surface as the lens are fitted in the V-shaped groove of the substrate and are optically coupled with each other. Anti-reflection structure in the switch. 6. A plurality of optical fibers on the master side are fitted in a plurality of V-shaped grooves of a substrate, and a lens array having an antireflection coating on at least the front surface is disposed as an end face of the substrate as the lens. An antireflection structure in the optical switch described.