JPH0364844B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical device in which two optical elements such as optical waveguides are aligned and fixed with high precision while maintaining optical coupling.

In recent years, due to dramatic improvements in the performance of optical semiconductor elements, optical waveguides, etc., optical fiber communications, optical information processing, etc. have reached the stage of practical use. However, in these optical fiber communications and optical information processing, the light source,
In order to maintain optical coupling, transmission lines, light-receiving elements, optical circuits, etc. must be aligned and fixed with an accuracy of usually several μm to several + μm, and must be held with high reliability.

Conventionally, bonding and soldering have been used as this fixing means. However, problems with adhesion include that the fixing strength of the adhesive is not strong enough and that it lacks long-term reliability, that it takes a long time to bond, and that workability is not very high. In addition, in soldering, although there are few problems with fixing strength and workability, the heat during solder heating may have an adverse effect on the reliability of optical semiconductor elements, and the heat during solder heating may also cause thermal expansion of components. There were also problems such as shrinkage of the solder during solidification, which deteriorated optical bonding.

For example, if we take an example of an optical coupling device that couples the output light of a light emitting diode 1 to an optical fiber 2, as shown in the perspective view of FIG. 1 and the sectional view of FIG. 2, the light emitting diode 1 is connected to the base. It is fixed to a certain metal stem 3. A metal cylinder 4 is fixed to the stem 3. On the other hand, the optical fiber 2 is fixed to a terminal fitting 5 which is a fixed object. The terminal fitting 5 and the stem 3 are held by a fine movement mechanism (not shown), and their positions are adjusted so that the output light of the light emitting diode 1 is efficiently coupled to the optical fiber 2.
In this position adjusted state, solder material 9 is poured into the entire gap between the metal cylinder 4 and the terminal fitting 5 through a soldering iron, whereby the terminal fitting 5 is connected to the stem 3.
It is soldered on top.

In such a conventional example, in order to properly solder the terminal fitting 5 and the metal cylinder 4, the entire surface of the soldering area of the terminal fitting 5 and the metal cylinder 4 must be heated to near the melting point of the solder material 9. No. In this case, these heats spread to the stem 3, the light emitting diode 1, and the optical fiber 2, raising the temperature of these components by as much as 100 to 200°C. For this reason, there were drawbacks such as a decrease in the reliability of the light emitting diode 1 and a decrease in coupling efficiency of 20% or more due to positional displacement due to thermal expansion or the like.

The present invention solves these problems and provides an optical coupling device that does not reduce reliability or optical coupling due to heating when using a joining member that requires heating such as solder. The purpose is

The optical coupling device of the present invention includes a first optical element, a base holding the first optical element, and a second optical element optically coupled to the first optical element.
The fixed body includes a fixed body that holds the second optical element and a fixing table provided on the base, and a plurality of holes are provided in the fixed body facing the fixing table, The first and second optical elements are optically coupled, and the object to be fixed is fixed to the fixing base by a bonding material injected into the hole.

The present invention provides a base having a first optical element and a second optical element.
When fixing an object to be fixed having an optical element using a bonding material, a fixing base with a fixing point provided on the base;
It is limited only to the hole formed in the object to be fixed corresponding to the fixing base. By doing this, the spread of heat when heating the bonding material is reduced, which may adversely affect the first and second optical elements thermally, or the base and the fixed object may thermally expand, causing damage to the optical element. It is possible to prevent the optical coupling between the two from decreasing. In addition, since the holes are arranged at equal intervals or at almost symmetrical positions in the circumferential direction around the optical axis of the optical element, positional deviation due to thermal expansion is canceled out in the direction perpendicular to the optical axis. , the decrease in optical coupling can be further reduced.

Hereinafter, the present invention will be explained in detail based on Examples. FIG. 3 is a perspective view for explaining the first embodiment of the present invention, and FIG. 4 is a sectional view. This first embodiment is an example of an optical coupling device that optically couples a light emitting diode 1, which is a first optical element, and an optical fiber 2, which is a second optical element.

The light emitting diode 1 is fixed to a metal stem 3 which is a base. A ceramic plate 6 and a metal plate 11, which serve as fixing bases, are brazed to the stem 3, respectively. On the other hand, the optical fiber 2 is fixed to a terminal fitting 5 which is a fixed body, and the terminal fitting 5 has a hole 7 corresponding to the metal plate 11, which is approximately symmetrical to the optical axis of the output light of the light emitting diode 1. There are several locations.

A lead wire 12 for feeding power to the light emitting diode 1 is fixed to the stem 3 via an insulating material 13, and is connected to the light emitting diode 1 by a thin aluminum wire 14.

The terminal fitting 5 and the stem 3 are held by a fine movement mechanism (not shown), and their positions are adjusted so that the output light of the light emitting diode 1 is efficiently coupled to the optical fiber 2. At this time, the distance between the light emitting diode 1 and the metal plate 11 and the optical fiber 2 are adjusted so that the metal plate 11 does not touch the terminal fitting 5 and creates a gap of 0.2 to 0.5 mm.
The positional relationship between the entrance end 8 and the terminal fitting 5 is determined. Then, in this position adjusted state, the hole 7
From there, solder material 9 is poured onto metal plate 11 via a soldering iron, thereby fixing terminal fitting 5 to stem 3.
fixed on top.

In the optical coupling device 10 thus obtained, the solder material 9 is heated and fixed only to the hole 7 and a part of the metal plate 11 facing the hole 7. The soldering work can be completed while there is little heat conduction to the soldering process. Therefore, the optical elements such as the light emitting diode 1 and the optical fiber 2 may be adversely affected by heating, such as a decrease in reliability, and the stem 3, the terminal fitting 5, etc. may thermally expand, causing damage between the light emitting diode 1 and the optical fiber 2. Less reduction in coupling loss. Furthermore, since the stress generated when the solder material 9 solidifies and contracts acts approximately isotropically around the central axis of the hole 7, the stresses cancel each other out at least in the direction perpendicular to the optical axis of the optical fiber 2. A new effect was also discovered in that it prevents misalignment.

In fact, in the first embodiment, the temperature rise when soldering the solder material 9 was about 20 degrees Celsius for the light emitting diode 1 and about 50 degrees Celsius for the optical fiber 2. Further, the reduction in the coupling efficiency between the light emitting diode 1 and the optical fiber 2 could be suppressed to 5% or less, a value that does not pose a practical problem. This is a significant improvement over the conventional method, where the temperature of both the light emitting diode and optical fiber increased by 100 to 200 degrees Celsius, and the coupling efficiency decreased by more than 20%.

FIG. 5 is a perspective view for explaining a second embodiment of the present invention, and FIG. 6 is a sectional view. The second embodiment is a semiconductor laser 20 which is a first optical element.
The output light 21 of
This is an example of an optical coupling device 10 that couples light 23 to parallel light 23 and converts it into parallel light 23.

The semiconductor laser 20 is fixed to a metal stem 3 that is a base. A metal cylinder 4 serving as a fixed base is fixed to the stem 3. On the other hand, the ball lens 22 is fixed to a metal ball lens holder 24 which is a fixed object, and the ball lens holder 24
A total of six holes 7 for injecting solder material 9 are provided at equal intervals in the circumferential direction centered on the optical axis of the output light of the semiconductor laser 20. Note that a lead wire 12, an insulating material 13, and a thin aluminum wire 14 are provided for power supply to the semiconductor laser 20.

The ball lens holder 24 and the stem 3 are held by a fine movement mechanism (not shown), and their relative positions are adjusted so that the output light 21 of the semiconductor laser 20 becomes substantially parallel light 23. Then, in this aligned state, solder material 9 is poured from the hole 7 onto the metal cylinder 4 via a soldering iron, thereby fixing the ball lens holder 24 onto the metal cylinder 4.

In the second example as well, it was possible to obtain an optical coupling device 10 with less positional deviation, less temperature rise, etc., as in the first example.

Regarding the present invention, many modifications are possible in addition to the above-described embodiments. Examples of the first optical element include the light emitting diode 1 and the semiconductor laser 20, and examples of the second optical element include the optical fiber 2 and the ball lens 22. A light source such as a gas laser, a converging rod lens with a squared refractive index profile, a passive element such as a plane waveguide, a waveguide type optical switch, an ultrasonic light modulation element, and various other optical elements are used as the first and second optical elements. It can be used as an optical element.

In addition to the solder material 9, various brazing materials, adhesives, etc. can be used as the bonding material. Further, although an example of heating with a soldering iron is shown as a heating method, various other methods such as heating with a burner, high frequency, resistance wire, laser beam, etc. are possible.

Although the fixing table has been shown as an example of a cylindrical shape, it may have a shape other than that, for example, a rectangular shape. Similarly, the shape of the hole 7 may also be other than a cylindrical shape.

In the first embodiment, a ceramic plate 6 with a metal plate 11 brazed thereon is used as the fixing base, but it may also be a ceramic plate on which a metal thin film is vapor-deposited. Further, if the bonding material is an adhesive or the like, the metal plate 11 is not necessary.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a conventional example, FIG. 2 is a sectional view, FIG. 3 is a perspective view showing a first embodiment of the present invention, FIG. 4 is a sectional view, and FIG. FIG. 6 is a perspective view showing the embodiment, and FIG. 6 is a sectional view as well. Here, 1 is a light emitting diode, and 20 is a semiconductor laser, each of which corresponds to a first optical element. 3 is a stem that corresponds to the base. 2 is an optical fiber, and 22 is a ball lens, each of which corresponds to a second optical element.
5 is a terminal fitting, and 24 is a spherical lens holder, each of which corresponds to a fixed object. 4 is a metal cylinder, 6 is a ceramic plate, and 11 is a metal plate, each of which corresponds to a fixing base. 7 is a hole, and 9 is a solder material.

Claims (1)

[Claims] 1 A first optical element, a base holding the first optical element, a second optical element optically coupled to the first optical element, and a cover holding the second optical element. a fixing body and a fixing table provided on the base, and the fixing body facing the fixing table is provided at equal intervals in a circumferential direction centering on the optical axis of the second optical element. , or in a nearly symmetrical position,
In a state where a plurality of holes are provided and the first and second optical elements are optically coupled, the object to be fixed is fixed by a bonding material that requires heating injected into the holes. An optical coupling device, characterized in that it is fixed to the fixed base.