JP3088859B2 - Anti-reflection structure in optical switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In a mechanical optical switch for switching or interrupting an optical path by moving an optical fiber on a master side and a plurality of optical fibers in a direction orthogonal to the optical axis, one or more optical switches on a master side are used. The optical coupling is performed by selectively abutting the end faces of the optical fibers of the book and the end faces of the optical fibers on the many sides arranged at equal intervals.

In this optical switch, a matching oil is sometimes used on the end face of the optical fiber in order to prevent end face reflection between the optical fiber on the master side and the optical fibers on many sides. This matching oil is generally used in a state where the end face of the optical fiber is immersed in the oil.However, since the optical switch is driven and performs a switching operation, it is technically difficult to hermetically seal the matching oil. Are difficult to maintain, and the matching oil is difficult to maintain due to aging. For this reason, the matching oil cannot satisfy the condition of 100,000 switching operations required for the optical switch or the condition of durability for 10 years.

On the other hand, it has been attempted to apply an anti-reflection coating (AR coating) to the end face of an 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 hermetically sealed like a matching oil. Therefore, it is convenient for an optical switch or the like. However, it is difficult to uniformly apply an anti-reflection coating 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.

[0007] Referring to FIG. 7, the tip of the optical fiber 1 on the master side is inserted into a ferrule 3, and the optical fibers 2 on many sides are respectively inserted into a plurality of V-grooves 5 formed on a substrate 4. Each optical fiber 2
Are maintained with the interval accuracy maintained. The optical fibers 2 on the multiplicity side may be held by one substrate 4, but there are many optical paths to be switched, and when 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 held down by a holding plate 6 to constitute a fiber holder 7 as a whole.

[0006]

In many optical switches, the front end face 7a of the fiber holder 7 has a length of 20 mm.
It becomes a plane of about (width) x 30 mm (height). But,
It is technically very difficult to uniformly apply an anti-reflection coating to each end face 2a of a large number of optical fibers 2 arranged on the front end face 7a of the fiber holder 7. That is, in order to apply an anti-reflection coating to the end face of the optical fiber 2, the fiber holder 7 is placed in a vacuum container (not shown) and vacuum-deposited. Because the optical fiber 2 is elongated, it is difficult to handle it.
In particular, since the long optical fiber 2 is guided to the outside through the wall of the vacuum container, there is a problem that it is difficult to maintain a vacuum in the container.

An object of the present invention is to provide an anti-reflection structure in an optical switch which has solved the above-mentioned problems.

[0008]

An anti-reflection structure in an optical switch according to the present invention comprises an optical connection between end faces of an optical fiber on a master side and an optical fiber on a multiplicity side. In an optical switch that switches by moving a fiber in a direction orthogonal to its optical axis,
A lens disposed on the front side of the master side optical fiber and having at least a front surface provided with an anti-reflection coating, and a glass plate adhered to the end surfaces of many optical fibers and having a light incident surface provided with an anti-reflection coating. The end faces of the optical fibers on the master side and the optical fibers on the many sides are provided at an interval for maintaining the image forming relationship.

As the above-mentioned lens, a convex lens, a grain lens, a plano-convex lens or the like can be used.

An optical fiber on the master side may be fitted into a V-groove of the substrate, and a grain fiber having at least a front surface provided with an antireflection coating as the lens may be optically coupled.

Further, when there are a plurality of optical fibers on the master side, each optical fiber is fitted into a plurality of V-grooves of the substrate,
It is preferable to dispose a lens array having an antireflection coating on at least the front surface on the end surface of the substrate.

[0012]

According to the structure of the present invention, the light emitted from the optical fiber on the master side passes through the lens, further passes through the glass plate, and forms an image on the end faces of the optical fibers on the many sides. At this time, since the lens and the glass plate are uniformly coated with the anti-reflection coating before assembling them into the optical switch, a smooth switching operation is performed without connection loss or loss variation. .

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of an optical switch according to a first embodiment, in which fiber end faces 1a and 2a of an optical fiber 1 on a master side and optical fibers 2 on a multiplicity side are provided 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 beyond the tip of the inner ferrule 8.

A convex lens 10 is disposed on the opening edge 9a of the outer ferrule 9, and the end face 1 of the optical fiber 1 is provided.
a is provided at a fixed interval. The antireflection coat 11 is applied to both surfaces of the convex lens 10, and the antireflection coat 11 is also applied to the end face 1 a of the optical fiber 1.

On the other hand, the plurality of optical fibers 2 are fitted into the V-grooves 5 of the substrate 4 with their end faces 2a flush with each other, and the optical fibers 2 are arranged with an equal interval P between them. The optical fiber array 12 is constituted as a whole. Each optical fiber 2
An 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 an antireflection coat 11 applied to the front surface. It is adhered. This glass plate 13 is provided in a size that can cover a large number of optical fibers 2.

In the above configuration, the end face 1a of the optical fiber 1 on the master side and the end face 2a of the
Are arranged at an interval having an image forming relationship via the convex lens 10. Therefore, according to this optical switch, the light emitted from the optical fiber 1 on the master side is
0, and further passes through the glass plate 14 to form an image on the end face 2a of the optical fiber 2 on the many sides.

In the optical switch of the first embodiment, instead of applying an anti-reflection coating to the end faces 2a of the optical fibers 2 on many sides as in the prior art, instead of applying an anti-reflection coating to the end face 2a, An antireflection coat 11 is applied. The application of the antireflection coat 11 to the glass plate 14 is performed by putting the glass plate 14 in a vacuum container (not shown) in a state of a single glass plate before assembling the glass plate 14 into an optical switch. It is easy to maintain a high vacuum inside the vacuum vessel, and the antireflection coat 1
1 can be applied.

The optical fiber 1 on the master side is much easier to handle than the optical fiber 2 on the master side.
There is no problem in applying 1 uniformly.

Similarly to the above, the convex lens 10 is placed in a vacuum container in a state of a single convex lens before being incorporated into the optical switch, and the coating operation is performed. The reason for providing the convex lens 10 is as follows. That is, as shown in FIG.
Is used, 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 many sides are arranged apart, 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, an antireflection coating 11 is applied to the end face 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, light is not reflected at the end face between the optical fiber 1 on the master side and the optical fibers 2 on many sides, so that connection loss can be suppressed.

In the optical switch of the first embodiment,
Since a closed space 15 is formed between the end face 1a of the optical fiber 1 and the convex lens 10, this space 15 may be filled with a matching silicone oil. In this case, it is unnecessary to apply the antireflection coat 11 on the end face of the optical fiber and the antireflection coat 11 on one side of the convex lens 10.

Next, an optical switch according to a 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 surfaces is used. Other configurations are the same as in the first embodiment. In the optical switch of the second embodiment as well, the end face 1a of the optical fiber 1 on the master side and the end face 2a of the optical fiber 2 on many sides have an image forming relationship via the grain lens 16, and the optical fiber on the master side The optical path can be switched without moving the optical path 1 and causing end face reflection.

An optical switch according to a third embodiment will be described with reference to FIG. In the optical switch of the third embodiment, a plano-convex lens 17 having a flat base end surface and a convex front end surface is used instead of the convex lens 10 of the optical switch of the first embodiment. The anti-reflection coating 11 is applied to the base end surface and the front end surface of the plano-convex lens 17. Other configurations are the same as in the first embodiment. In the optical switch of the third embodiment as well, the end face 1a of the optical fiber 1 on the master side and the end face 2a of the optical fiber 2 on many sides are in a connected relationship via the plano-convex lens 17, and the optical fiber 1 on the master side is connected. The optical path can be switched without causing reflection by causing the light to move.

An optical switch according to a fourth embodiment will be described with reference to FIG. In the optical switch according to the fourth embodiment, a grain fiber 18 is used instead of the convex lens 10 of the optical switch according to the first embodiment. This grain fiber 18
And the optical fiber 1 on the master side are fitted into large and small V-grooves 20 and 21 formed continuously on the substrate 19, and this V-groove 2
The alignment of the master-side optical fiber 1 and the grain fiber 18 is performed within 0 and 21. The antireflection coating 11 is also applied to both end faces of the grain fiber 18. Other configurations are the same as in the first embodiment.

In the optical switch of the third embodiment as well, the end face 1a of the optical fiber 1 on the master side and the end face 2a of the optical fibers 2 on many sides have an image forming relationship via the grain fiber 18, and together with the substrate 19 Optical fiber 1 on master side
Can be switched without causing end surface reflection by moving the optical path.

An optical switch according to a fifth embodiment will be described with reference to FIG. The optical switch according to the fifth embodiment differs from the first to fourth embodiments in that it has a plurality of optical fibers 1 on the master side. 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 of the optical fibers 1 on the master side has a plurality of large and small V-grooves 20 formed at equal pitches on the substrate 19.
It is fitted in 21 small grooves.

The large fibers of the V-grooves 20 and 21 of the substrate 19 are fitted with grain fibers 18 coated with the anti-reflection coating 11 on both end surfaces at a predetermined interval from the end surfaces of the optical fiber 1. I have. Also, the end face 1a of the optical fiber 1
A rod-shaped glass component 22 is fitted between the glass fiber 18 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
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 face 2a of the optical fiber 2 on many sides have an image forming relationship via the grain fiber 18, and the master side has an image forming relationship. The optical path can be switched without moving the optical fiber 1 to cause end face reflection.

An optical switch according to a sixth embodiment will be described with reference to FIG. In this optical switch, similarly to the optical switch of the fifth embodiment, the plurality of optical fibers 1 on the master side are fitted into V-grooves 20 formed in the substrate 19 with their end faces aligned. The optical switch of the sixth embodiment is different from that of the fifth embodiment in that the lens array 23 is in close contact with the end surface of the substrate 19 via the adhesive 13. This lens array 23
A large number of lenses 23 b are buried at equal intervals on the front surface of the glass plate 23 a, and the lenses 23 b are arranged at intervals such that the centers thereof are aligned with the center lines of the optical fibers 1.
An antireflection coating 11 is provided on the front surface of the lens array 23.
Is applied.

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

In the optical switch of the sixth embodiment as well, the end face 1a of the optical fiber 1 on the master side and the end face 2a of the optical fibers 2 on many sides 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 and causing end face reflection.

In addition to the above embodiments, the end faces 2a of the optical fiber 1 on the master side and the optical fibers 2 on the multiple side are arranged in an image-forming relationship via lenses, and the optical fibers 2 on the multiple side are arranged. The structure of the lens, the structure for supporting 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 face 2a of the optical fiber 1.

[0034]

According to the anti-reflection structure of the optical switch of the present invention, a glass plate is used as an optical switch component in which an anti-reflection coat can be easily applied uniformly. In addition, by adhering the glass plate to the end faces of the optical fibers on many sides, it was possible to overcome the technical difficulty of applying an anti-reflection coat evenly on the end faces of the optical fibers on many sides as in the past. . In addition, the problem of light diffusion between optical fibers facing each other at intervals with the use of this glass plate is that the end faces of the optical fibers on the master side and the optical fibers on the many sides are separated through a lens having an anti-reflection 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, it is possible to overcome the technical difficulty of using the optical switch anti-reflection coat and provide an optical switch with a small connection loss.

[Brief description of the drawings]

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

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

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

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

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

FIG. 6 is a partially cut 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
Groove, 10: convex lens, 11: anti-reflection coating, 14: glass plate, 16: grain lens, 17: plano-convex lens, 1
8 ... Grain fiber, 23 ... Lens array.

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-55-138703 (JP, A) JP-A-57-20702 (JP, A) JP-A-61-109009 (JP, A)

Claims (6)

(57) [Claims] An optical switch for switching an optical connection between end faces of a master side optical fiber and a multiplicity of optical fibers by moving the master side and a multiplicity of optical fibers in a direction orthogonal to an optical axis thereof. A lens disposed on the front side of the master side optical fiber and having at least a front surface provided with an anti-reflection coating, and a glass plate adhered to the end surfaces of many optical fibers and having a light incident surface provided with an anti-reflection coating. An anti-reflection structure in an optical switch provided at an interval in which end faces of optical fibers on the master side and the optical fibers on many sides maintain an image forming relationship. 2. An anti-reflection structure in an optical switch according to claim 1, wherein said lens is a convex lens. 3. An anti-reflection structure in an optical switch according to claim 1, wherein said lens is a grain lens. 4. The lens according to claim 1, wherein said lens is a plano-convex lens.
An antireflection structure in the optical switch described in the above. 5. The light according to claim 1, wherein the master-side optical fiber and a grain fiber having at least a front surface provided with an anti-reflection coating as the lens are fitted into a V-groove of the substrate, and the two are optically coupled. Anti-reflection structure in switch. 6. A lens array in which a plurality of optical fibers on the master side are fitted into a plurality of V-grooves of a substrate, and an end surface of the substrate is provided with a lens array having at least a front surface provided with an antireflection coating as the lens. An antireflection structure in the optical switch described in the above.