JPH10221563A - Input/output integrated connection member and optical waveguide type device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connecting member which connects an optical fiber with an input/output terminal of an optical waveguide element using simple assembling process such that the optical fiber is certainly positioned, and provide an inexpensive optical waveguide device which reduces number of components and assembling process. SOLUTION: The connecting member simultaneously includes an input side connection part 1 which can contact with an input surface B1 of an optical waveguide element (B) and an output side connection part 2 which can contact with an output surface B2 of the element. The input side connection part 1 and the output side connection part 2 are integratedly formed through an intermediate supporting part 3 such that two connection parts are separated by distance into which the element (B) is inserted in its input/output direction. In addition, the input side connection part 1 and the output side connection part 2 have supporting structures (for example, an optical fiber supporting groove) 7, 8 which support optical fibers F1, F2 so that optical fiber's end surfaces fit with end surfaces of optical waveguide appearing on input and output surfaces of the element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input / output integrated connection member used for connecting an optical fiber to an input / output portion of an optical waveguide element, and an optical waveguide connected to the optical fiber by the connection member. About the device.

[0002]

2. Description of the Related Art An optical waveguide element is an element having an optical circuit obtained by using basic elements of an optical waveguide such as linear, bent, branched, and coupled. This optical circuit is not limited to a circuit using the basic elements of the optical waveguide alone, but also a combination of these elements, and a circuit in which electrodes and the like are arranged to control the flow of light with voltage and current. Are known. For example, a 1 × N branch circuit is used for distribution of an optical signal such as application to an optical subscriber system in optical fiber communication.

An optical waveguide device is used by connecting an external optical waveguide such as an optical fiber. FIG. 3 is a schematic diagram showing an exploded state of a conventional connection structure between an optical waveguide element and an optical fiber. As shown in the figure, the optical waveguide element B is usually a hexahedron having an input surface and an output surface,
The optical waveguide B3 is formed on a surface layer. FIG. 1 illustrates a simple Y-branch (1 × 2 branch) type optical waveguide. Input surface B1 and output surface B which are connection end surfaces of the element
2, the end face of the optical waveguide B3 appears, and the element and the optical fiber are connected by aligning the end face of the optical fiber with this end face. Further, there is a type in which light can be input from the output surface and output from the input surface by exchanging the input surface and the output surface.

In the present specification, in the optical waveguide element, the surface on which the optical waveguide is formed is the “upper surface”, the opposite surface is the “lower surface”, and the side surface when going from the “input surface” to the “output surface”. The faces (the remaining two faces) are called “side faces”. A device in which an optical fiber is connected to an optical waveguide element is called an “optical waveguide device”.

As shown in FIG. 3, external optical fibers 23, 24 and 25 are connected to an end face B1 of an input side B31 and an end face B2 of output sides B32 and B33 of an optical waveguide B3. For the connection, an input-side connection member 21 and an output-side connection member 22 are separately used as members for assisting the close contact between the minute end faces of the optical waveguide and the optical fiber. These connecting members are attached to the input surface B1 and the output surface B2 of the optical waveguide element while holding the optical fiber and forming a block, whereby the end surface of each optical fiber is connected to the input surface of each optical waveguide. It adheres to the end face and is joined. An adhesive is usually used for joining.

[0006]

When an optical fiber is connected to an optical waveguide element, the optical waveguide of the element and the optical fiber must be joined in a state where the optical axes are aligned very accurately. Therefore, in order to join the connecting member to each of the input surface and the output surface of the optical waveguide element, a measurement method capable of detecting a small deviation between the optical axes and a relative position of the member based on the measurement are described. An advanced positioning technique with a displacement means capable of precisely displacing the position by a very small amount is required.

For example, an optical fiber is held in a connecting member to form a block, and the optical waveguide element and the connecting member are joined in a state where the light passes through the optical fiber, and positioning is performed while observing light from the opposite end. It is not easy to accurately connect the connecting member to each of the input and output surfaces of the optical waveguide element.

SUMMARY OF THE INVENTION An object of the present invention is to provide a connection for connecting an optical fiber to both an input surface and an output surface of an optical waveguide element at the same time and in a highly positioned state by a simple assembling operation. An object of the present invention is to provide a member, reduce the number of components and the number of assembling steps by using the member, and provide a low-cost optical waveguide device.

[0009]

The input / output integrated connection member according to the present invention has the following features. (1) An input / output integrated connection member to be attached to an optical waveguide element and connected to an optical fiber, the input side connection portion being capable of contacting the input surface of the element, and the input side connection portion being capable of contacting the output surface of the element. The input side connection part and the output side connection part are connected at a distance capable of sandwiching the optical waveguide element in the input / output direction, and the input side connection part and the output side connection are provided. The department is
An optical fiber holding structure capable of holding the optical fiber so that the optical axis of the optical fiber coincides with the optical axis of the optical waveguide appearing on the input surface and the output surface of the element, for an input / output integrated connection. Element.

(2) The input side connection part and the output side connection part are
The intermediate support is integrally formed by an intermediate support that connects them so as to secure the above-mentioned interval, and the intermediate support is provided so as to be in close contact with one side surface of the optical waveguide element and to be a reference surface for positioning at the time of mounting. The input / output integrated connection member according to the above (1), wherein

(3) The input side connection part and the output side connection part are:
The intermediate support is integrally formed by an intermediate support that connects them so as to secure the above-mentioned interval, and the intermediate support is provided so as to be in close contact with one side surface of the optical waveguide element and serve as a reference surface for positioning during mounting. The optical fiber holding structure holds the optical fiber in an optical fiber holding groove provided on a surface of each of the input side connection portion and the output side connection portion corresponding to the optical waveguide surface of the optical waveguide element. The input / output integrated connection member according to the above (1), wherein the optical fiber holding groove is processed using the reference surface of the intermediate support portion as a reference for position determination.

(4) A plurality of sets of the optical fiber holding groove of the input side connection part and the optical fiber holding groove of the output side connection part are formed so as to be on the same straight line with each other. The input / output integrated connection member according to the above (3), wherein the fiber holding groove is formed at the same time by the passage of the cutting tool in the same cutting step.

(5) The surfaces of the input-side connecting portion and the output-side connecting portion that are in contact with the input surface and the output surface of the optical waveguide element, respectively, have the optical axes of the optical fibers held in the respective optical fiber holding grooves. (3) The input / output integrated connection member according to the above (3), which forms an angle of 12 ° or less with a plane perpendicular to.

Further, in the optical waveguide device of the present invention, the input / output integrated connection member according to any one of the above (1) to (5) is mounted on an optical waveguide element, and an input surface and an output surface of the element are provided. Is connected to an optical fiber. Hereinafter, the input / output integrated connection member according to the present invention is referred to as “connection member of the present invention” or simply “connection member”.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1 as an example, a connecting member A of the present invention comprises an optical waveguide element (hereinafter referred to as an "element"B; It has a structure in which an output-side connection portion 2 that can contact the output surface B2 of the element B is formed so as to be integrated with the output-side connection portion 2. In the case of FIG. The side connection part 2 is formed with a space that allows the element B to be sandwiched and held in the input / output direction by the connection surface 4 and the connection surface 5 simultaneously contacting the input surface B1 and the output surface B2, respectively. The input side connection part 1 and the output side connection part 2 are optical fibers F1, F2
(Only the entire width is shown by a two-dot chain line in FIG. 1) at a predetermined position.
The predetermined position where the optical fiber is to be held is a position where the end surfaces of the optical fibers F1 and F2 can be connected to the end surface of the optical waveguide B3 appearing on the input surface B1 and the output surface B2 of the element B so as to match. Is determined in advance according to the specifications of the target element. In the element B shown in the figure, a 1 × 8 optical star coupler is shown as a simple example of the optical waveguide B3. The cover members 9 and 10 are accessory parts described later.

With this configuration, when connecting the optical fiber to the element, only the optical axis relationship between the optical waveguide and the optical fiber on one of the input side and the output side is determined, and the other is also positioned. Is done. Therefore, it is not necessary to perform individual positioning adjustment on the input side and the output side as in the related art.

In order to form the input side connection part and the output side connection part integrally, a space between the input side connection part and the output side connection part is ensured and a part for connecting them, that is, an intermediate support part exists. I do. The intermediate support portion may be provided in any way so as to be bridged between the input side connection portion and the output side connection portion as long as the position does not hinder the mounting to the element. Examples are provided on the surface,
As shown in FIG. 1, a mode in which the device is provided at a position where it can be in close contact with one side surface of the element is preferable. At this time, the surface (reference surface) 6 that is in close contact with one side surface of the element serves as a reference for positioning when the element is mounted.

An intermediate support portion is provided as shown in FIG. 1, and its reference surface 6 is used as a reference for positioning at the time of mounting on an element, and the reference surface 6 is used for processing an optical fiber holding structure. By using it as a reference surface, it is possible to easily complete all the optical axis adjustments simultaneously simply by setting the side surface of the element to the reference surface of the intermediate support.

The method of forming the input side connection part and the output side connection part as an integral structure is not limited, and a plurality of parts may be assembled and formed. Since high dimensional accuracy is required for the parts related to optical axis adjustment, the entire body is integrated into a single body by molding (cutting, polishing, etc. may be used), cutting from one material block, etc. It is preferably formed as

The material used for the connecting member of the present invention (including the cover member as an accessory part thereof) is not limited, but a material having a linear expansion coefficient close to the linear expansion coefficient of the element to be mounted is preferable. Glass such as quartz glass or Pyrex glass, ceramics using alumina, zirconia, or the like, liquid crystal polymer-based plastics, silicon, and the like, as well as materials similar to those used in conventional connection members are used.

In the embodiment shown in FIG. 1, since the element B having the optical waveguide formed on the upper surface is to be mounted, the optical fiber holding structures provided on the input side connection part 1 and the output side connection part 2 are also provided. The structure holds the optical fiber on each upper surface. Hereinafter, the optical fiber holding structure in the embodiment of FIG. 1 will be described.

The structure for holding the optical fiber is a simple structure, and the optical fiber can be positioned with high accuracy and stability. Therefore, as shown in FIG. Preferably, at least a required number of optical fiber holding grooves (hereinafter simply referred to as “holding grooves”) 7 and 8 are provided, and the optical fiber is held using these grooves.

The shape of the cross section perpendicular to the longitudinal direction of the holding groove may be a V shape, a rectangular shape, an arc shape, or the like. In particular, the workability of the groove, high precision and stable when holding the optical fiber. From the viewpoint of positioning, a V-shaped groove is preferable.

When the optical fiber is held by using the holding groove, the optical fiber may be simply arranged along the groove and fixed with an adhesive. However, as shown in FIG. The structure using the members 9 and 10 protects the optical fiber, enables the end face treatment for the connection of the optical fiber to be firmly held to facilitate the processing, and makes the connection state with the optical waveguide a large area. It is preferable in that it can be stably fixed at.

In the case of the structure shown in FIG. 1, the position of the center axis of the holding groove is determined by using the reference surface 6 of the intermediate support portion 3 as a reference for position determination, and the optical fiber held in the groove is determined by cutting. Can be accurately matched with the position of the optical axis on the end face of the optical waveguide to be connected.

As shown in a simple example in FIG. 2A, the optical axis at the end of the optical waveguide that appears on the input surface B1 and the output surface B2 of the element B is a set of b1 and b3, and a set of b2 and b4. like,
When they are on the same straight line, as shown in FIG. 2B, the holding grooves 7a and 7b of the input-side connection portion 1 and the holding grooves 8a and 8b of the output-side connection portion 2 are changed to 7a and 8a. Set of 7,
Like the set of b and 8b, they can be formed so as to be on the same straight line with each other. In such a case, in the same cutting step, a cutting tool can be cut through, for example, from the groove 7a to the groove 8a, so that a set of grooves having high coaxiality is obtained.

Even if the number n of inputs and the number N of outputs of the optical waveguide of the element are different such that n <N, the input-side and output-side connecting portions are provided with holding grooves of a larger number N or more. If only necessary grooves are used after processing, even connection members having the same holding groove pattern can be used for connection with elements of various optical waveguide patterns.

In the case where all the forms shown in FIG. 2B are formed by cutting, the processing of the holding grooves (7a, 8a) and (7b, 8b) and the processing of forming the space S in which the element is to be fitted are described. , Which may be performed first.

In order to reduce the reflection of light at the connection surface (boundary surface) between the optical waveguide and the optical fiber, the connection surface and the optical axis should not be perpendicularly intersected but the perpendicular of the connection surface should be perpendicular to the optical axis. Between,
It is preferable to provide a specific angle corresponding to the numerical aperture NA (Numerical Aperture) of the optical waveguide. Therefore, as shown in FIG. 1, in the element B, the connection end faces B1, B2
And a plane perpendicular to the optical axis of the optical waveguide B3 are formed so as to form a specific angle. In the connecting member A of the present invention, the input and output connecting surfaces 4, 5 and Grooves 7, 8
It is preferable that the optical fiber is formed so that a plane perpendicular to the optical axis of the optical fiber held therein forms a specific angle (at an angle opposite to that of the element so as to be in close contact with the connection end face of the element). The specific angle is, for example, 8 ° for a single mode fiber and 12 ° for a multimode fiber.

The optical waveguide device of the present invention is one in which an optical fiber is connected to the input and output surfaces of the element using the connecting member of the present invention. The external end face of the optical fiber connected to the element (the end face opposite to the connection face with the element) can be freely processed, but it is necessary to connect the optical fiber to the optical transmission device or optical transmission line. A connector may be attached.

The method for fixing the connection member of the present invention to the element is preferably a method of bonding and fixing the input / output surface of the element and the connection surface of the connection member using an adhesive. The adhesive used is, like the conventional connection member, an epoxy-based or acrylate-based ultraviolet-curable adhesive,
Although a thermosetting adhesive and the like can be mentioned, an ultraviolet curable adhesive can shorten the curing time, and is preferable in performing a high-precision and high-speed assembling operation.

The device may be any device having an input / output surface of an optical waveguide. For example, N × M
Elements such as a splitter, a WDM splitter, and a thermo-optic switching are included.

[0033]

EXAMPLES The present invention will be specifically described below with reference to examples. In this embodiment, a 2 × 16 splitter was used as an element, and an optical fiber was connected to this using the connecting member of the present invention to form an optical waveguide device. This element functions as a branch circuit having two inputs and 16 outputs, and the input surface and the output surface are inclined by 8 ° from a plane perpendicular to the optical axis of the optical waveguide. Further, the positional relationship among the input side connection portion, the output side connection portion, and the intermediate support portion of the connection member in this embodiment is the same as that shown in FIG. The material was made of Pyrex glass, and all were formed by cutting and polishing from a single material block.

The outline of the procedure for assembling the optical waveguide device is as follows. 1. A predetermined optical fiber was placed in each holding groove of the input side connection part and the output side connection part, covered with a cover member, and fixed with a photocurable resin adhesive. 2. The end face of the optical fiber fixed to the connection member of the present invention was polished in accordance with the inclination of the surface of the input side connection portion and the surface of the output side connection portion, and finished as a connection surface. 3. The element is brought into contact with the surface of the input-side connection portion, the surface of the output-side connection portion, and the reference surface of the intermediate support portion, and is fitted therein. Completed. As a result, it was confirmed that the optical axes could be aligned with high accuracy without complicated positioning work.

[0035]

As described above, the connecting member of the present invention can be simultaneously joined to the input / output ends of the element by a simple assembling operation in a state where the optical fibers are highly positioned at the input / output ends of the element. It is. Therefore, by this connecting member,
If the optical waveguide device is formed, the number of parts and the number of assembling steps can be reduced, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a view showing an example of a connection member of the present invention together with an element.

FIG. 2 is a diagram showing an example of an optical waveguide of an element and a formation pattern of a holding groove in a connecting member of the present invention.

FIG. 3 is a schematic view showing an exploded state of a conventional connection structure between an element and an optical fiber.

[Explanation of symbols]

 Reference Signs List A Connection member 1 Input side connection part 2 Output side connection part 3 Intermediate support part 4, 5 Connection surface of connection member 6 Reference surface 7, 8 Optical fiber holding groove 9, 10 Cover member B Optical waveguide element B1, B2 Input surface and output surface of optical waveguide device F1, F2 Optical fiber

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yasuhide Sudo 4-3 Ikejiri, Itami-shi, Hyogo Mitsubishi Electric Cable Industry Co., Ltd. Itami Works

Claims (6)

[Claims] 1. An input / output integrated connection member for connecting an optical fiber mounted on an optical waveguide element, comprising: an input-side connection portion capable of contacting an input surface of the element; An output-side connection portion that can come into contact with the input-side connection portion and the output-side connection portion, the input-side connection portion and the output-side connection portion are connected at an interval capable of sandwiching the optical waveguide element in the input / output direction; The side connection portion has an optical fiber holding structure capable of holding the optical fiber so that the optical axis of the optical fiber coincides with the optical axis of the optical waveguide appearing on the input surface and the output surface of the element. Output integrated connection member. 2. An input side connection part and an output side connection part are integrally formed by an intermediate support part which connects them so as to secure the above-mentioned interval, and the intermediate support part is provided on one side of the optical waveguide element. The input / output integrated connection member according to claim 1, wherein the member is provided so as to be in close contact with a side surface and to be a reference surface for positioning at the time of mounting. 3. An input side connection part and an output side connection part are integrally formed by an intermediate support part which connects them so as to secure the above-mentioned interval, and the intermediate support part is provided on one side of the optical waveguide element. The optical fiber holding structure is provided on the surface corresponding to the optical waveguide surface of the optical waveguide element in each of the input-side connection portion and the output-side connection portion. 2. A structure for holding an optical fiber in the provided optical fiber holding groove, wherein the optical fiber holding groove is processed using a reference surface of the intermediate support portion as a reference for position determination. I / O integrated connection member. 4. An optical fiber holding groove at an input side connection portion,
A plurality of sets of optical fiber holding grooves of the output side connection part are formed so as to be on the same straight line with each other, and two sets of optical fiber holding grooves of each set are formed simultaneously by passage of a cutting tool in the same cutting process. The input / output integrated connection member according to claim 3, wherein 5. The input-side connection portion and the output-side connection portion, which are in contact with the input surface and the output surface of the optical waveguide element, respectively, correspond to the optical axis of the optical fiber held in each optical fiber holding groove. The input / output integrated connection member according to claim 3, wherein the member is formed at an angle of 12 ° or less with a vertical plane. 6. The input / output integrated connection member according to claim 1, which is mounted on an optical waveguide device, and an optical fiber is connected to an input surface and an output surface of the device. Optical waveguide device.