JPH09184939A - Optical module and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical module, having plural optical components fixed in a specified relation while disalignment at the time of fixation by a laser welding method is reduced, and its manufacturing method. SOLUTION: A 2nd component is made to butt against a 1st component 7 to be welded and a viscous material 9 is charged between the contact surfaces of both the components 7 and 8. The 1st component 7 and 2nd component 8 are held in contact with each other by making use of the viscosity of the viscous material 9 without requiring any jig. Then, the butting surfaces or their peripheries are welded and fixed by the laser welding method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module in which an optical element and an optical fiber are optically connected and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a so-called pigtail optical module in which an optical fiber is optically connected to an optical element has been used in fields such as optical communication and optical measurement. As a method of making a pigtail of an optical element, mainly a semiconductor laser, there is a method of using a spherical lens or a spherical fiber whose spherical fiber end is processed. Are aligned and fixed so that they can be efficiently input to the optical fiber.

The positional accuracy of alignment depends on the optical components used, but accuracy of several microns to submicrons is required, and high positional accuracy is required. In order to fix optical components while maintaining such high positional accuracy, it is necessary to select a fixing method and make various efforts.

As one of the fixing methods, there is a laser welding method in which a part of an optical component is melted by using a YAG laser or the like and integrated with other components, and one example thereof is disclosed in Japanese Patent Laid-Open No. 2-250009. It is shown. This method is suitable for processing minute parts such as optical parts, and is useful as a method for semi-permanently and completely fixing parts.

However, the laser welding method has a problem in that the components are displaced at the moment of welding and the alignment is not performed properly. As a method for avoiding this, for example, in Japanese Patent Laid-Open No. 3-116108,
A method in which a laser welding method and an ultraviolet curable adhesive are used together is shown. Prior to the former laser welding, the latter adhesive is temporarily positioned.

[0006]

However, the use of an ultraviolet-curable adhesive as in the above-mentioned Japanese Patent Laid-Open No. 3-116108 is effective in preventing misalignment, but has a drawback. First, it is conceivable that the parts to be welded are generally opaque, and therefore the adhesive in the gap is less likely to be exposed to ultraviolet rays and the adhesive is not completely cured.
In such a case, the solvent of the uncured adhesive may remain in the optical module and volatilize, which may adversely affect the long-term reliability of the optical element. The other is that the UV irradiation for curing the adhesive is required, which lengthens the working time or increases the number of manufacturing steps. Therefore, it is necessary to devise a method that makes the most of the advantages of the laser welding method with the simplest method.

By the way, as described in the above-mentioned Japanese Patent Laid-Open No. 3-116108, the cause of the misalignment caused by the laser welding method is an intermediate component for fixing the component (for example, described later). (1) The existence of a one-sided clearance when two parts (for example, a welding ring and a support base described later) are pressed against each other (for example, a clearance is provided between the welding ring and the ferrule). Therefore, the former tends to tilt with respect to the latter, and when these are pressed against the part to be welded (for example, the support base described later), this inclination causes the welding ring and the support base to contact with each other on the side opposite to the contact site. There are two points: the presence of stress that occurs during the process of melting and solidification. If these two points are improved, it is expected that a laser welding method with less misalignment at the time of fixing.

Therefore, an object of the present invention is to solve the above two problems and to provide an optical module in which a plurality of optical components are fixed in a predetermined relationship by the laser welding method to reduce misalignment at the time of fixing, and a manufacturing method thereof. To provide.

More specifically, the object of the first invention of the present application is to use a viscous material to hold both the first and second parts to be welded without holding them with a jig. No gap is generated on the contact surface (claims 1, 5,
(Corresponding to 6, 7, 8, 12, 13, 14).

A second object of the present invention is to use an adhesive for the viscous material (corresponding to claims 2 and 9).

The third object of the present invention is to suppress the adverse effect of volatile substances from the viscous material for temporary fixing (corresponding to claims 3 and 10).

A fourth object of the present invention is to suppress the occurrence of a gap between parts due to the thickness of the viscous material filled for temporary fixing (corresponding to claims 4 and 11). ).

[0013]

In order to achieve the above object, a first invention according to the present application is to provide a viscous material on a contact surface of both parts where a second part abuts on a first part to be welded. It is characterized by filling. With the above configuration,
By virtue of the viscosity of the viscous material, the first part and the second part are kept in contact with each other without the need for a jig.

Specifically, in the optical module of the first invention according to the present application, the second member to be welded abuts against the first member to be welded, and the abutting surface or its periphery is laser welded. An optical module welded and fixed by a method is characterized in that one of the first member and the second member is temporarily fixed to the other by a viscous material incorporated in the optical module.

In the method for manufacturing an optical module according to the first invention of the present application, the second member to be welded abuts the first member to be welded, and the abutting surface or its periphery is a laser. In a method of manufacturing an optical module which is welded and fixed by a welding method, the first member and the second member are made different by viscous material incorporated in the optical module.
One of the members is abutted against the other to temporarily fix both members, and then both members are welded and fixed at at least one place.

In order to achieve the above object, the second invention of the present application is characterized in that an adhesive having a viscosity required for temporary fixing is used as the viscous material, and the third invention is an adhesive. It is characterized by using a natural hardening type. With the above structure, long-term stability is secured by suppressing volatile substances that affect the elements, electrodes, etc. and independently curing after the work is completed.

To achieve the above object, the fourth invention of the present application provides one or more grooves or notches for filling a viscous material on one or both contact surfaces of parts to be temporarily fixed. It is characterized by that. With the above configuration, it is possible to prevent a gap from being generated between the components due to the thickness of the viscous material filled for temporary fixing. Therefore,
Since the adhesive force for temporary fixing is generated in the groove portion filled with the viscous material and the frictional force is generated in the portion other than the groove due to the contact with the surface of the quantity component, the shift due to the stress of (2) can be suppressed. . .

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment FIGS. 1 and 2 show a first embodiment of the present invention. FIG. 1A is an assembled sectional view of the optical module from the upper surface, and FIG. 1B is a sectional view of the optical module from the side surface. FIG. 2 is a diagram showing a centering method in laser welding.

The structure of the optical module will be described with reference to FIG. The semiconductor laser 1, which is one optical element, is mounted on the stem mount 4 and further arranged on the Peltier element 5. A heat sink 6 is attached to the heat radiation side of the Peltier element 5.

On the other hand, the other optical element, the spherical fiber 2
Is assembled to the fiber ferrule 3 with its tip protruding. The ferrule 3 is aligned at a position where the light emitted from the semiconductor laser 1 is maximally coupled to the front spherical fiber 2, and is passed through a support base 7 with a welding ring 8 supporting the ferrule 3 as an intermediary and further fixed. There is. The support base 7 is fixed to the heat sink 6 in a predetermined relationship. The welding point is the fiber ferrule 3 from above the welding ring 8 in order to integrate the welding ring 8 and the fiber ferrule 3.
The first point 50 that is pierced through and is lapped and welded,
It is two points of the second point 60 which is butt-welded to integrate the support base 7 and the welding ring 8. Also,
Each welding point is fixed at two points evenly distributed on the circumference (see FIG. 1 (a)). This number is an example, and it may be welded at three or more points at equal intervals.

As described above, since the support base 7 is fixed to the heat sink 6 in advance, all of the above parts are assembled together. These parts are housed in the package 10 and assembled as an optical module.

Next, the alignment of the optical axis and the laser welding work are shown in FIG. 2 (viewed from above), and the function and action of the viscous material 9 in this embodiment will be described.

The semiconductor laser 1 is kept at a constant temperature by an external temperature controller (not shown) and is driven by an external LD driver 14 at a constant current. On the other hand, the front spherical fiber 2 inserted into the fiber ferrule 3 is held by a holder 12 and set on a triaxial stage 13 of xyz axes. At this time, the fiber ferrule 3 is set up by passing the welding ring 8 around the outer periphery thereof. Two cutouts (grooves) are provided (as an example) on the surface of the welding ring 8 that contacts the support base 7 (see FIG. 1).
As shown in (b), the welding ring 8 is provided so as to extend vertically along the radial direction), and the groove is filled with grease 9 which is a viscous material. As a result, the welding ring 8 is attached to the support base 7 side by the grease 9 made of a viscous material and temporarily fixed. The viscosity required for the temporary fixing depends on the size and weight of the member to be temporarily fixed and the size of the surface to be temporarily fixed, but the grease 9 has the necessary viscosity. Tip spherical fiber 2
The other end of is connected to a fiber connector, which connects to the photodetector 15.

The centering work is performed by moving the fiber ferrule 3 by the triaxial stage 13 to find the point where the detection power of the photodetector 15 is maximum. In the xy-axis directions, it is movable by the difference between the inner diameter of the hole formed in the support base 7 and the outer diameter of the fiber ferrule 3. In this state, after welding the welding ring 8 which is the first welding point 50 and the fiber ferrule 3, the ferrule 3 is pressed toward the LDl side by about 1 μm and the support base 7 which is the second welding point 60.
And the abutting portion of the welding ring 8 are welded and integrated.

As described above, the main causes of misalignment at the time of welding are (1) existence of one-sided clearance generated when two parts are pressed together (2) individual welding points occurring in the process of melting and solidification There are two points of the existence of stress applied to.

The grease 9 partially filled on the outer periphery of the ferrule 3 temporarily fixes the ring 8 to be welded to the support base 7 without any gap. Therefore, the problem of (1) one-sided clearance is that the metal nail or the tension spring is used. It is greatly improved compared to the method of pressing from the outside by using such as. In addition, since the groove is filled, it is possible to prevent a gap from being generated between the components due to the thickness of the viscous material filled for temporary fixing.

Further, since the grease 9 is partially filled, friction of the metal surface of the other butting surface causes
The effect of suppressing the shift due to stress which is the factor of (2) can be expected. The elimination of the one-sided clearance, which is the factor of (1), also greatly contributes to elimination of the deviation due to the stress of (2). As described above, the present configuration in which the viscous grease 9 is filled has an effect of significantly improving the factors (1) and (2), which are factors that cause the misalignment, and accordingly, the misalignment is also caused. It is possible to make it smaller.

Furthermore, this structure has the effect of simplifying the work process. The viscous grease 9 always attaches the welding ring 8 to the support base 7 even when performing fine adjustment in the z-axis direction. Therefore, the welding setup is completed at the same time as the centering, and no complicated operation is required. Therefore, as shown in FIG. 2, if the triaxial stage 13 is automatically controlled while detecting the power of the photodetector 15, and the welding YAG laser light emitting section 16 is also linked by the automatic stage by the controller 11. , Full automation is also possible.

Second Embodiment As a second embodiment, FIG. 3 (cross-sectional view seen from the side), FIG.
There is something like the one shown in (Cross-section view from above). This is a case where a module is configured using two lenses 121 and 122. Here, the LD 1 fixed to the package 110 via the submount 123 and the Peltier element 105.
The rod lens 122, which is also fixed to the package 110, is integrated with the 0l and the ball lens 121 so as to form a desired coupling system. The optical fiber ferrule 103 is fixed to this end so that the optical coupling is optimum. In this case as well, the welding ring 108 is used for three-axis adjustment and then fixed. As in the first embodiment, the weld ring 108 is partially provided with a notch (groove) on the circumference of the contact surface with the metal component 125 around the rod lens (in the present embodiment, As shown in FIG. 4, the welding ring 108
The welding ring 108 is temporarily fixed by using grease 109 which is a viscous material and is provided so as to extend horizontally along the radial direction on the contact surface.

Welding is performed at the first welding point 150 and the second welding point 150.
It is done at welding point 160. Other points are the same as the first embodiment.

In the above embodiment, grease was used as the viscous material, but other viscous materials can be used.
For example, it is possible to use an adhesive having a viscosity required for temporary fixing in an uncured state. In addition, by using an adhesive that naturally cures without applying an action such as ultraviolet irradiation as the adhesive, it is possible to suppress the generation of volatile substances due to the uncured adhesive and achieve long-term stabilization.

[0032]

As described above, according to the present invention,
The following effects are obtained. By temporarily fixing one member of the two members to be welded (each placed in a predetermined state with respect to the optical component) to the other member with a viscous material, 1. It is possible to manufacture optical modules with less misalignment during welding. This has the effect of simplifying the manufacturing process.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment according to the present invention,
(A) is an assembly sectional view from the upper surface, and (b) is an assembly sectional view from the side surface.

FIG. 2 is a diagram showing operations of centering and laser welding for the first embodiment.

FIG. 3 is an assembled sectional view from the side showing a second embodiment according to the present invention.

FIG. 4 is an assembled sectional view from the upper surface showing a second embodiment according to the present invention.

[Explanation of symbols]

 1, 101 semiconductor laser 2 tip spherical fiber 3, 103 fiber ferrule 4 stem mount 5, 105 Peltier element 6 heat sink 7 support base 8, 108 welding ring 9 viscous material 10, 110 package 50, 150 first welding point 60, 160 2 Welding points 121 Ball lens 122 Rod lens 123 Submount 125 Metal parts around the rod lens

Claims (14)

[Claims] 1. An optical module in which a second member to be welded abuts a first member to be welded, and the abutting surface or its periphery is welded and fixed by a laser welding method, and a viscous material is used. An optical module, wherein one of the first member and the second member is temporarily fixed to the other. 2. The optical module according to claim 1, wherein the viscous material is an adhesive having a viscosity required for temporary fixing. 3. The optical module according to claim 2, wherein the adhesive is a self-curing adhesive. 4. The viscous material is filled in one or more grooves provided on a contact surface of one or both of the first member and the second member. The optical module according to claim 1, wherein: 5. The first member to be welded is fixed to the semiconductor laser in a predetermined relationship, and the second member to be welded supports an optical fiber. Item 1. The optical module according to item 1. 6. The optical module according to claim 5, wherein the second member to be welded supports the optical fiber via a fiber ferrule. 7. The optical module according to claim 6, wherein the second member to be welded and the fiber ferrule are aligned and welded and fixed. 8. A method of manufacturing an optical module, wherein a second member to be welded abuts against a first member to be welded, and the abutting surface or its periphery is welded and fixed by laser welding. The viscous material causes one of the first member and the second member to abut against the other to temporarily fix both members, and then both members are welded and fixed at at least one place. A method of manufacturing a characteristic optical module. 9. The method of manufacturing an optical module according to claim 8, wherein the viscous material is an adhesive having a viscosity required for temporary fixing. 10. The method of manufacturing an optical module according to claim 9, wherein the adhesive is a self-curing adhesive. 11. The viscous material is filled in one or more grooves provided in a contact surface of one or both parts between the first member and the second member. 9. The method for manufacturing an optical module according to claim 8, which is characterized in that. 12. The welded first member is fixed to the semiconductor laser in a predetermined relationship, and the welded second member supports an optical fiber. A method for manufacturing the described optical module. 13. The method of manufacturing an optical module according to claim 12, wherein the second member to be welded supports the optical fiber via a fiber ferrule. 14. The optical module according to claim 13, wherein the second member and the fiber ferrule to be welded are aligned and welded to each other before the two members are welded to each other. Production method.