JPH0311307A - Method for coupling light receiving and emitting element and optical fiber - Google Patents

Abstract

PURPOSE:To facilitate the alignment work by forming a groove, whose width is approximately equal to that of a light receiving and emitting element, on the element mounting face of a substrate to make the light receiving and emitting element movable in the optical axis direction, and providing an optical fiber fixing groove on an optical fiber fixing face so that the designated optical axis of an optical fiber is placed on the optical axis of the light receiving and emitting element. CONSTITUTION:A groove 13b whose width is approximately equal to that of a light receiving and emitting element 11 is formed on an element mounting face 13a of a substrate 13, and an optical fiber fixing plate 14 wider than the groove 13b is fixed on the element mounting face 13a. An optical fiber fixing groove 14a having such depth is formed in a position corresponding to the groove 13b on the optical fiber fixing plate 14 that the optical axis of an optical fiber 12 is placed at the same height as the light reception and emission area at the time of mounting the element 11 in the groove. The light receiving and emitting element 11 is placed and fixed in the groove 13b on the element mounting face 13a so that its light reception and emission area is directed to the optical fiber fixing plate 14, and the optical fiber 12 is inserted and fixed in the optical fiber fixing groove 14a so that its end face is directed to the element 11. Thus, the alignment work which aligns optical axes and attains a maximum optical coupling efficiency is facilitated.

Description

[Detailed Description of the Invention] (Summary) Regarding the coupling method of the light receiving/emitting element and the optical fiber, this invention is mounted on a substrate for the purpose of facilitating the optical axis alignment work and the alignment work to obtain the maximum optical coupling efficiency. A method of coupling a light receiving/emitting element and an optical fiber in which the optical axis of a light receiving/emitting element and the optical axis of an optical fiber fixed to the substrate are aligned, and the width of the element mounting surface of the board is approximately equal to the width of the light receiving/emitting element. After forming a groove and fixing an optical fiber fixing plate having a width at least wider than the shallow groove on the element mounting surface so as to cover a part of the shallow groove, the groove formed in the substrate on the optical fiber fixing plate and An optical fiber fixing groove is formed at the same position and has a depth such that the optical axis of the optical fiber is located at the same height as the receiving/emitting area when the receiving/emitting element is mounted in the groove, and A light receiving/emitting element is mounted and fixed in the groove so that the light receiving/emitting area of the light receiving/emitting element faces the optical fiber fixing plate, and an optical fiber is placed in the optical fiber fixing groove on the optical fiber fixing plate. The optical fiber is inserted and fixed so that its end face faces toward the light receiving/emitting element.

(Industrial Application Field) The present invention relates to an optical coupling system between a light receiving/emitting element and an optical fiber in an optical communication device, etc., and particularly aims to facilitate optical axis alignment work and alignment work to obtain maximum optical coupling efficiency. The present invention relates to a method for coupling light emitting/receiving elements and optical fibers.

Generally, in optical communication equipment, optical fibers are often connected to light-emitting elements such as semiconductor lasers or light-receiving elements such as LEDs, and in particular, for these connections, it is necessary to align the optical axes of the two to achieve maximum optical coupling efficiency. It is necessary to find a position that can be obtained,
Therefore, alignment work on the order of microns is required.

[Conventional technology]

FIG. 2 is a diagram illustrating a conventional method of coupling a light receiving/emitting element and an optical fiber.

In the figure, a case will be explained in which a semiconductor laser is used as a light receiving/emitting element.

In FIG. 2, one side of a substrate 1 made of, for example, silicon (Si) shown in (1) includes an element mounting surface 1a on which a semiconductor laser is mounted and an optical fiber fixing surface 1b on which an optical fiber is fixed.
It is formed with a step.

Therefore, as shown in (2), the optical fiber fixing surface lb
A groove 1c for fixing a predetermined optical fiber is formed on the top using a dicing saw, etc. In this case, the width a of the shallow groove 1c is approximately equal to the outer diameter of the optical fiber to be used, and the depth d is The height of the optical axis of the optical fiber from the element mounting surface 1a when the optical fiber is fixed in the shallow groove 1c and the light emitting area 2a from the element mounting surface 1a when the semiconductor laser 2 is mounted on the element mounting surface 1a. The heights are made to be the same.

For example, if we take the outer diameter of the optical fiber, the height difference between the element mounting surface 1a and the optical fiber fixing surface 1b, and the height from the bottom surface of the semiconductor laser 2 used to the light emitting region 2a as h, then The width a is calculated as aζD, and the depth d of the groove 1c is calculated as follows: d=t+(D/2)-h.

Next, as shown in (3), a predetermined semiconductor laser 2 is placed on the element mounting surface 1a so that its light emitting region 2a faces the optical fiber fixing surface lb, and the groove 10 has an outer diameter. D, and the optical fiber 3 whose tip end surface 3a has a convex hemispherical shape in order to increase optical coupling efficiency is formed into a shallow groove 1 so that its tip end surface 3a protrudes somewhat from the step forming surface 1d.
Insert it from the top of 0 and fix it with adhesive such as ultraviolet curing resin.

At this point, the optical axis of the semiconductor laser 2 and the optical axis of the optical fiber 3 are located on the same plane.

Therefore, while detecting the amount of light transmitted from the other end (not shown) of the optical fiber 3, the semiconductor laser 2 is moved on the element mounting surface la, and the optical axis of the semiconductor laser 2 and the optical fiber 3 are moved. The semiconductor laser 2 is adhesively fixed to the element mounting surface 1a in that state by finding a position where the optical axes of the semiconductor laser 2, that is, the core 3b coincide with each other and the maximum optical coupling efficiency is obtained.

Figure (4) shows this state, and 4 indicates the adhesive explained in (3).

In the case of such a coupling method, since it is necessary to move the semiconductor laser in two-dimensional directions, there is a drawback that matching of the optical axes and alignment work require a lot of man-hours.

Note that the same effect can be obtained even if a light receiving element such as an LED is used in place of the semiconductor laser.

[Problem to be solved by the invention]

The conventional method of coupling a light receiving/emitting element and an optical fiber has a problem in that the matching of the optical axes and the alignment work require a lot of man-hours because it is necessary to move the light receiving/emitting element in at least two dimensions.

[Means to solve the problem]

The above-mentioned problem lies in the coupling method of the light emitting and receiving elements and the optical fiber, which aligns the optical axes of the light receiving and emitting elements mounted on the board with the optical axes of the optical fibers fixed to the board. forms a groove approximately equal to the width of the light receiving/emitting element, and fixes an optical fiber fixing plate having a width at least wider than the shallow groove onto the element mounting surface so as to cover a part of the shallow groove, and then fixing the optical fiber fixing plate. At the same position as the groove formed in the above substrate, provide an optical fiber fixing groove with a depth such that the optical axis of the optical fiber is located at the same height as the light receiving/emitting area when the light receiving/emitting element is mounted in the groove. A light emitting/receiving element is mounted and fixed in the groove on the element mounting surface so that the light emitting/receiving area of the light emitting/receiving element faces the optical fiber fixing plate, and the light emitting/receiving element is placed and fixed in the groove on the optical fiber fixing plate. This problem can be solved by a method of coupling the light emitting/receiving element and the optical fiber by inserting and fixing the optical fiber into the fiber fixing groove such that the end surface of the optical fiber faces the light receiving/emitting element.

(Function) When the light receiving/emitting element and the optical fiber are respectively placed in two grooves on the substrate formed so that the optical axis of the light receiving/emitting element and the optical axis of the optical fiber coincide, the work of aligning the optical axes becomes easy. It is possible to find a position where the maximum optical coupling efficiency can be obtained by simply moving in one direction along the shallow groove.

In the present invention, a groove approximately equal to the width of the light emitting/receiving element is formed on the element mounting surface of the substrate to enable movement of the light emitting/receiving element mounted in the shallow groove in the optical axis direction. A groove for fixing a predetermined optical fiber is provided so that the optical axis of the predetermined optical fiber is located on the optical axis of the light receiving/emitting element.

Therefore, since the optical axis of the light receiving/emitting element and the optical axis of the optical fiber are always aligned, the position where the maximum optical coupling characteristics can be obtained can be determined simply by moving the light receiving/emitting element or the optical fiber in one direction along the groove. It is possible to obtain a method for coupling a light emitting/receiving element and an optical fiber that can be detected and that alignment work is easy.

〔Example〕

FIG. 1 is a diagram explaining the present invention.

In addition, in the figure, a case will be explained in which a semiconductor laser is used as a light receiving/emitting element as in FIG. 2.

FIG. 1A shows an example of a semiconductor laser and an optical fiber used, and the width of the semiconductor laser 11 is A.

The height from the bottom surface to the light emitting region 11a is defined as H.

The optical fiber 12 has an outer diameter of D, and the tip end face 12a is formed into a convex hemispherical lens in order to increase optical coupling efficiency.

Note that 12b in the figure is a core.

In Figure (B), a substrate 1 made of, for example, silicon (St), etc.
The radiation A of the semiconductor laser 11 is placed on the element mounting surface 13a of No. 3.
(for example, 300 μm) and a depth s of 100 to 300 μm are formed using a dicing saw.

Next, as shown in Figure (C), a portion of the groove 13b is at least wider than the shallow groove 13a and has a thickness t.

An optical fiber fixing plate 14 made of the same material and having a corner of about 300 μm is fixed with a common resin adhesive or the like.

Further, the substrate 13 is placed on the surface of the optical fiber fixing plate 14.
When an optical fiber fixing groove 14a parallel to the shallow groove is formed using the groove 13b formed in 1 as a reference, the same dicing saw used for the substrate 13 is set in the same state as when forming the groove 13b, as shown in Figure (D). It can be in the state shown.

Note that the optical fiber fixing groove 1 on the optical fiber fixing plate 14
4. The position and direction of a can be easily formed by a centering operation using a microscope or the like using the position and direction of the groove 13b of the substrate 13 as a reference.

In this case, especially the width a of the optical fiber fixing groove 14a.

is approximately equal to the outer diameter D (for example, 125 μm) of the optical fiber used, and the depth dI is set to the diameter dI of the semiconductor laser 1 used.
As explained in FIG. 2, the value is determined by 1, the dimensions of the substrate, etc.

For example, in the case of the figure, it is the outer diameter of the optical fiber 12.

The thickness of the optical fiber fixing plate 14 is tI+the depth of the groove 13b formed in the substrate 13 is 3. , since the height from the bottom surface of the semiconductor laser 11 to the light emitting region 11a is H, the groove 14a
The width a1 of a1! :iD If the depth d of the groove 14a is d+=t++ (D/2) (Hs+), then the semiconductor laser 11 is placed in the groove 13b of the base Fj, 13 as shown in the figure, and the optical fiber 12 is When inserted into the optical fiber fixing groove 14a of the optical fiber fixing plate 14, the heights of the light emitting region 11a of the semiconductor laser 11 and the core 12b of the optical fiber 12 from the element mounting surface 13a can be made equal.

Therefore, for example, a semiconductor laser I is placed at a predetermined position in the groove 13b.
After adhesively fixing the optical fiber 12 so that its light-emitting region 11a faces the optical fiber fixing plate 14, the optical fiber 12 is inserted into the optical fiber fixing groove 14a so that its end surface 12a faces the light-emitting region 11a. becomes a matched state.

The cross-sectional view (E) shows this state.

However, the tip end surface 12a of the optical fiber 12 is formed into a convex hemispherical shape as described above.

Therefore, when the distance C between the semiconductor laser 11 and the optical fiber 12 is changed, the amount of optical signal emitted from the light emitting region 11a and incident on the end face 12a of the optical fiber 12 changes.

Therefore, without detecting the amount of light transmitted at the other end (not shown) of the optical fiber 12, the optical fiber 12 is inserted into the groove 14a.
By moving the optical fiber 12 along the groove 14a, it is possible to find the point with the greatest amount of light, that is, the point with the best optical coupling characteristics. Therefore, it is possible to adhesively fix the optical fiber 12 in the groove 14a in that state to realize the desired coupling. can.

Note that the same effect can be obtained by moving the semiconductor laser 11 along the groove 13b after fixing the optical fiber 12 to the groove 14a.

In the case of this method of coupling the semiconductor laser and optical fiber, there is no need for optical axis alignment work, and complete alignment can be achieved by moving in one direction along the groove, so that the semiconductor laser and optical fiber can be bonded in the best condition. A join can be made to .

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a method for coupling a light emitting/receiving element and an optical fiber, which facilitates alignment work for aligning optical axes and maximizing optical coupling efficiency.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining the present invention, and Fig. 2 is a diagram for explaining a conventional coupling method between a light receiving/emitting element and an optical fiber. is an optical fiber, 12a is an end face, 12b is a core, 13 is a substrate, 13a is an element mounting surface, 13b
14 is a groove, 14 is an optical fiber fixing plate, and 14a is an optical fiber fixing groove. Name 1 (A (E3) (E) Book day and month! Department and B month ゛ o 3 shi) Figure 1

Claims (1)

[Scope of Claims] A method for coupling a light receiving/emitting element and an optical fiber in which the optical axis of a light receiving/emitting element mounted on a substrate matches the optical axis of an optical fiber fixed to the substrate, the method comprising: an element on a substrate (13); A groove (13b) whose width is approximately equal to the width of the light receiving/emitting element (11) is formed on the mounting surface (13a), and an optical fiber fixing plate (13b) which is at least wider than the groove (13b) is formed.
14) on the element mounting surface (13a) so as to cover a part of the groove (13b), and then fix the groove (13b) formed in the substrate (13) on the optical fiber fixing plate (14). the groove (13b) at the same position as
The light receiving/emitting area (1) when the light receiving/emitting element (11) is mounted on the
An optical fiber fixing groove (14a) with a depth such that the optical axis of the optical fiber is located at the same height as 1a) is formed, and a receiving/emitting element (14a) is formed in the groove (13b) on the element mounting surface (13a).
11) in the light receiving/emitting region (11a) of the light receiving/emitting element (11).
) is placed and fixed so that it faces the optical fiber fixing plate (14), and the optical fiber fixing groove (
The optical fiber (12) is connected to the optical fiber (14a).
2) A method for coupling a light emitting/receiving element and an optical fiber, characterized in that the end face (12a) is inserted and fixed so as to face the light emitting/receiving element (11).