JPH0311308A - Method for forming optical coupling part of optical module - Google Patents

Abstract

PURPOSE:To facilitate the alignment work of an optical fiber and to improve the optical coupling characteristic by forming an optical fiber cutting groove, which is orthogonal to the optical fiber and has a prescribed depth to cut the optical fiber, and forming a light receiving and emitting element mounting face to widen the cutting groove while keeping the depth of the cutting groove. CONSTITUTION:After an optical fiber cutting groove 10b which is orthogonal to an optical fiber 3 and has a prescribed depth to cut the optical fiber is formed on an insulating substrate 10 to which the optical fiber 3 is fixed, a light receiving and emitting element mounting face 10c is formed to widen the cutting groove 10b while keeping the depth of the cutting groove 10b. When the optical fiber 3 is cut together with the substrate 10, the cut face of the optical fiber 3 is exposed to the cut face of the substrate 10. A light receiving and emitting element 2 is positioned as required by only one-dimensional movement. Thus, the optical coupling forming method of an optical module is obtained which facilitates the alignment work between the optical fiber and the light receiving and emitting element and improves the optical coupling characteristic.

Description

[Detailed Description of the Invention] [Summary] Regarding a method for forming an optical coupling part of an optical module consisting of an optical fiber and a light receiving/emitting element, the present invention aims to facilitate the alignment work of the optical fiber with respect to the light receiving/emitting element and improve the optical coupling characteristics. A method for forming an optical coupling part between an end of an optical fiber fixed to a substrate and a light receiving/emitting element mounted on the substrate, the method comprising: After forming the optical fiber cutting groove of a predetermined depth for cutting the optical fiber, a light receiving/emitting element mounting surface is formed so as to widen the width of the cutting groove while maintaining the depth of the cutting groove. Configure.

There is also a method for forming an optical coupling part between an end of an optical fiber fixed to a substrate and a light receiving/emitting element mounted on the substrate, the method comprising: forming an optical coupling part between an end of an optical fiber fixed to a substrate and a light emitting/receiving element mounted on the substrate; After forming an optical fiber cutting groove with a depth to cut the optical fiber, a predetermined value is left in the width direction of the cutting groove from the wall side of the cutting groove where the optical fiber connected to the other end is exposed, A light emitting/receiving element mounting surface is formed at a predetermined position deeper than the cutting groove.

[Industrial application field]

The present invention relates to an optical coupling system between an optical fiber and a light receiving/emitting element,
In particular, the present invention relates to a method for forming an optical coupling part of an optical module, which facilitates alignment of an optical fiber and a light receiving/emitting element and improves optical coupling characteristics.

Generally, in an optical module consisting of an optical fiber and a light emitting/receiving element such as a photodiode (P, D) or a light emitting diode (L, D), the optical axis of the optical fiber, that is, the core axis, and the light emitting/receiving element are connected at the optical coupling part. In addition to aligning the optical axes of the two opposing surfaces, it is necessary to make them parallel with a gap of approximately 10 to 20 μm between the two opposing surfaces to avoid damage due to contact. However, there is currently a strong desire to develop an efficient optical coupling method.

[Conventional technology]

FIG. 3 is a diagram illustrating a conventional method of coupling a light receiving/emitting element and an optical fiber.

Note that a case will be described below in which a semiconductor laser is used as a light receiving/emitting element.

In FIG. 3, one side of a substrate l made of, for example, silicon (St) 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 IC 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 10 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 to the shallow groove IC, and the light emission from the element mounting surface 1a when the semiconductor laser 2 is mounted on the element mounting surface 1a. The height h up to the area 2a is made equal.

Next, as shown in (3), the 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 1b, and the groove 10 has an outer diameter. An optical fiber 3 having a diameter of D is inserted from the top of the shallow groove 1c so that its tip end surface 3a is located substantially on the same plane as the step forming surface 1d, and is further fixed with an adhesive such as an ultraviolet curable 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 at 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 light of the optical fiber 3 are The position where the axes, that is, the core 3b match, is found, and the semiconductor laser 2 is adhesively fixed to the element mounting surface 1a in that state.

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

In the case of such a coupling method, it takes a lot of man-hours to position the optical fiber 3 with respect to the groove IC, and in order to align the optical axis of the semiconductor laser 2 with the optical axis of the optical fiber 3, the semiconductor laser 2 must be moved in a two-dimensional direction. There is a drawback that it must be moved to

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.

[Problems to be Solved by the Invention] In the conventional method for forming an optical coupling part of an optical module, there is a problem in that it takes a lot of man-hours to fix the optical fiber, and it is difficult to place the light receiving and emitting elements in a predetermined position with respect to the optical fiber. There is a problem in that the light receiving/emitting element must be moved at least in two-dimensional two-dimensional directions for positioning, and furthermore, a slight inclination of the optical axis causes variations in optical coupling characteristics.

[Means to solve the problem]

The above problem lies in the method of forming an optical coupling section between the end of an optical fiber fixed to a substrate and a light receiving/emitting element mounted on the substrate. After forming the optical fiber cutting groove of a predetermined depth for cutting the optical fiber, a light emitting/receiving element mounting surface is formed so as to widen the width of the cutting groove while maintaining the depth of the cutting groove. This problem is solved by a method for forming an optical coupling part of an optical module, which is characterized by the following.

Further, there is provided a method for forming an optical coupling portion between an end of an optical fiber fixed to a substrate and a light receiving/emitting element mounted on the substrate, the method comprising: After forming the optical fiber cutting groove deep enough to cut the optical fiber, the optical fiber is cut by leaving a predetermined value in the width direction of the cutting groove from the wall surface side of the cutting groove where the optical fiber connected to the other end is exposed. The problem is solved by a method for forming an optical coupling part of an optical module, which is characterized by forming a receiving/emitting element mounting surface at a predetermined position deeper than the groove.

[For production]

When the optical fiber is cut together with the substrate, the cut surface of the optical fiber is exposed on the cut surface of the substrate.

Furthermore, if the required positioning can be achieved by simply moving the light emitting and receiving elements in one dimension, the work of aligning the optical fiber and the light receiving and emitting elements can be facilitated.

In the present invention, the optical fiber is cut together with the substrate using a dicing saw or the like while the optical fiber is fixed to the substrate, so that the cut end surface of the optical fiber is exposed on the cut surface of the substrate.

Further, a convex step is formed on the line of intersection between the cut end face of the optical fiber and the light receiving/emitting element mounting surface perpendicular to the end face, the convex step being equivalent to a predetermined interval between the end face of the optical fiber and the light receiving/emitting element. There is.

Therefore, it is possible to eliminate the need for positioning the optical fiber with respect to the optical fiber fixing surface.

In addition, the positioning of the light receiving and emitting elements on the light receiving and emitting element mounting surface can be achieved by simply moving the light receiving and emitting elements along the above-mentioned convex step wall, which facilitates the work of aligning the optical fiber and the light receiving and emitting elements. This makes it possible to suppress variations in optical coupling characteristics.

〔Example〕

FIG. 1 is a process diagram illustrating the present invention.

FIG. 2 is a diagram illustrating another embodiment.

In FIG. 1 (2), 10 is an insulating substrate made of, for example, ceramic or glass.

Therefore, as shown in Figure 2, for example, a dicing saw 11 with a thickness t of about 200 μm is used in the r1 direction for 10,000 to 200
Arrow r while rotating at high speed to 00rp- position! A groove 10a is formed on the insulating substrate 10 with a width of 200 .mu.m and a predetermined depth d of 125 .mu.m, for example.

After that, an outer diameter of 12mm is placed in the predetermined position of the shallow groove 10a as in FIG.
After inserting the optical fiber 3 of 5 μm, the gap between the shallow groove 10a and the optical fiber 3 is filled with an adhesive 4 such as an ultraviolet curable resin to fix the optical fiber 3 in the groove 10a. shows this state.

Next, as shown in FIG. A groove 10b having a deeper predetermined depth is formed on the substrate lo in the same manner as in the above figure The cut end surface of the optical fiber 3 is exposed.

Further, the dicing saw 11 is moved in the direction of its rotational axis (r in the figure, in the force direction) by several tens of μm, for example, to cut the shallow grooves 1.
When 0b is expanded, the area A indicated by diagonal lines above the broken line is deleted and a light emitting/receiving element mounting surface 10c is formed, resulting in the state shown in FIG.

In particular, in this case, the depth of the groove 10b on the mounting surface 10c and the level difference from the surface of the insulating substrate 10 are
The height ho from c to the optical axis of the optical fiber 3 and the predetermined light receiving/emitting element (semiconductor laser in the figure) 2 explained in FIG.
The height h from the bottom surface to the optical axis (light emitting region in the figure) 2a is set to be equal.

Figure (2) shows a state in which the optical fiber 3 shown in Figure (2) is cut along a vertical plane along its longitudinal direction, and then a predetermined semiconductor laser 2 is fixed on the mounting surface 10c.

In this case, as explained in FIG. Optical axis alignment work can be performed simply by moving the semiconductor laser 2 while it is placed on the mounting surface 10c.

Therefore, there is no need to perform the positioning work of the optical fiber 3 as explained in FIG.

In FIG. 2 for explaining another embodiment, (1) is a dicing saw 11 similar to that described in FIG. groove 2 of saga d
0a, a predetermined optical fiber 3 is adhesively fixed in the shallow groove 20a with an adhesive 4, and after the substrate 20 or the dicing saw 11 is rotated 90 degrees, at least the optical fiber 3 on the substrate 20 is fixed. Shallow groove 20a at a position including the end face
A groove 20b is formed on the substrate 20, the groove 20b being deeper than the depth d of the groove 10b and slightly shallower than the groove 10b having the predetermined depth described in FIG.

Therefore, the shallow depression (1) corresponds to the case shown in FIG.

Next, the groove 20c is formed by moving the dicing saw 11 by, for example, 10 μ in the direction of its rotational axis (r in the figure, force direction) and lowering the dicing saw 11 to a predetermined depth as explained in FIG. As shown in FIG. 2, the cross section of the groove formed by the grooves 20b and 20c has stepped surfaces 20b'' and 20c'' at the bottom.

In this case, the width 20d of the 20b1 surface in the direction along the optical fiber 3 is 10 μm.

Thereafter, as explained in FIG.
1 in the direction of the rotation axis, that is, in the direction r in the figure, while widening the shallow groove 20c, the area A indicated by the diagonal line above the broken line
A light emitting/receiving element mounting surface 20d' is formed in which the step surface 20c° is enlarged by eliminating the angle 20d, resulting in the state shown in FIG. 3.

In this case, the depth of the groove 20c and the step difference liD° from the surface of the insulating substrate 20 on the receiving/emitting element mounting surface 20d° are set to be equal to the step amount D4 in FIG.

This means that the optical fiber 3
This means that the height h11 to the optical axis of is equal to hl in FIG.

Therefore, as shown in Figure (4), a semiconductor laser 2 similar to that shown in Figure 1 (■) is placed on the mounting surface 20d', and the semiconductor laser 2 is moved while being in contact with the vertical wall surface of the step surface 20b°. By simply doing this, it becomes possible to align the optical axis of the semiconductor laser 2 while maintaining a distance of 10 μm from the end face of the optical fiber 3.

Particularly in this case, the semiconductor laser 2 can be moved in a one-dimensional direction to perform a predetermined positioning operation, so it is possible to form the optical coupling part of the optical module extremely easily, and the distance between the semiconductor laser 2 and the end face of the optical fiber 3 can be extremely easily formed. Since a gap of 10 .mu.- is maintained at all times, the optical axis will not be tilted and the optical coupling characteristics will not vary, and the semiconductor laser 2 will not come into contact with the end surface of the optical fiber 3 and damage the end surface.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a method for forming an optical coupling portion of an optical module, which facilitates the alignment work between an optical fiber and a light receiving/emitting element and improves optical coupling characteristics.

[Brief explanation of the drawing]

Fig. 3 is a diagram illustrating a conventional method of coupling a light emitting/receiving element and an optical fiber. The light emitting element mounting surface, 20b' and 20c' are stepped surfaces, and 20d° is the receiving and emitting element mounting surface.

Claims (2)

[Claims] (1) A method for forming an optical coupling part between an end of an optical fiber fixed to a substrate and a light receiving/emitting element mounted on the substrate, the method comprising: attaching the optical fiber (3) to a substrate (10) fixed to the substrate; After forming the optical fiber cutting groove (10b) perpendicular to the fiber (3) and having a predetermined depth for cutting the optical fiber (3), while maintaining the depth of the cutting groove (10b), The light emitting/receiving element mounting surface (10
c) A method for forming an optical coupling part of an optical module, characterized by forming. (2) A method for forming an optical coupling part between the end of an optical fiber fixed to a substrate and a light receiving/emitting element mounted on the substrate, the method comprising: perpendicular to the fiber (3) and at least the optical fiber (3)
After forming the optical fiber cutting groove (20b) with a depth to cut the optical fiber, the cutting groove (20b) is formed to expose the optical fiber connected to the other end.
b) A receiving/emitting element mounting surface (20d') is formed at a predetermined position deeper than the cutting groove (20b) by leaving a predetermined value in the width direction of the cutting groove (20b) from the wall surface side. A method for forming an optical coupling part of an optical module.