JP3107155B2 - Semiconductor laser module - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser module in which an optical element and an optical fiber are mounted without adjustment.

[0002]

2. Description of the Related Art In recent years, in the field of optical communication, the application range of an optical communication network has been extended to subscribers, and miniaturization and cost reduction of semiconductor laser modules have become important issues. In order to cope with such a problem, in a semiconductor laser module, a coupling technology has been proposed in which an optical element and an optical fiber are mounted on the same substrate with high precision, the optical axis position is positioned without adjustment, and fixed to the substrate. I have.

As a well-known technique of such a coupling technique, for example, there is an optical coupling apparatus disclosed in Japanese Patent Application Laid-Open No. 61-185991.

FIGS. 4A and 4B show the basic structure of a semiconductor laser module provided in the optical coupling device, wherein FIG. 4A is related to a side view and FIG. 4B is a sectional view from the front. It is about. In this semiconductor laser module, a V groove 8a is formed on an InP substrate 8 by anisotropic etching in a direction parallel to the optical axis. Also, a resin introduction groove 7c having a bottom part several μm deep is formed by anisotropic etching. Optical fiber 3
Is fixed on the V-groove 6a by disposing the epoxy resin 5 from above the optical fiber 3 after being disposed on the V-groove 8a in close proximity to the emission end of the active region 9. The excessively applied resin flows into the resin introduction groove 7c formed at the bottom of the V groove 8a.

In the case of the semiconductor laser module having such a configuration, there are some problems. For example, the first problem is that the coupling efficiency of the active region 9 and the optical fiber 3 varies greatly. The reason is that the positioning of the optical axis requires an accuracy of the order of μm, whereas the epoxy resin 5 applied for fixing the optical fiber 3 is cured due to the stress of the optical fiber 3 itself. This is because the leading end of the optical fiber 3 is laterally displaced in a direction perpendicular to the optical axis during this time, and is displaced from the optimum coupling position with the active region 9.

A second problem is that the optical fiber 3 disposed on the V-groove 8a is easily peeled.
The reason is that the applied epoxy resin 5 is coated on the InP substrate 8.
This is because it flows into the V-groove 8a formed above and the optical fiber 3 is fixed only by the adhesion of the epoxy resin 5 in the V-groove 8a, so that the contact area is small and sufficient adhesive strength cannot be obtained. . Further, depending on the material of the epoxy resin 5, resistance to a temperature environment test such as a temperature cycle test may be poor.

As a technique for solving such a problem, there is, for example, a parallel transmission optical module disclosed in Japanese Patent Application Laid-Open No. 8-136768. FIG. 5 is a sectional view showing the basic configuration of the parallel transmission optical module (semiconductor laser module) from the front. In this semiconductor laser module, a V-groove 11b for arranging and fixing a plurality of optical fibers 3 on a substrate 11 with a V-groove, and a V-groove 1 for fixing guide pins 10 on both outer sides of the V-groove 11b.
1a is formed. Here, after arranging each optical fiber 3 and the guide pin 10 on the substrate 11 having a V-groove, the optical fiber 3 is pressed by a holding substrate 12 having a V-groove 12a for fixing the guide pin 10 to the V-groove 11a. The fiber 3 and the guide pin 10 are held, and in this state, they are bonded with a resin such as an ultraviolet curable resin or a two-component adhesive.
The cross-sectional shape of the holding substrate 12 has a V-shaped groove 12 a for fixing the guide pin 10.
No processing has been performed to fix this, and that part is flat.

Incidentally, other well-known technologies relating to the semiconductor laser module include, for example, Japanese Patent Application Laid-Open No. 8-327.
No. 859 discloses an optical semiconductor device and a method for manufacturing the same.

[0009]

In the case of the above-mentioned parallel transmission optical module (semiconductor laser module), a V-groove for fixing a guide pin is formed in a holding substrate, and processing for fixing an optical fiber is performed. Without using a flat plate.
The groove is fixed stably, but fixing the optical fiber in addition to the two guide pins at the same time means holding down three or more fibers at the same time. There is a problem that it tends to cause a decrease.

The processing accuracy of the V-grooves on each substrate for fixing the guide pins is in the order of submicron using any processing method such as anisotropic etching and mechanical polishing. Even if the guide pin is stably fixed in the V-groove, the optical fiber is likely to be misaligned by several μm even when a gap of several μm is generated between the optical fiber and the holding substrate. Also, under the condition that the accuracy of the order of μm is required for the alignment of the optical axis of the optical element, the coupling accuracy of the optical element and the optical fiber varies. Furthermore, there is a high possibility that the optical fiber is damaged by pressing the optical fiber with excessive strength, and in some cases, the optical fiber may be broken.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and its technical problem is to sufficiently suppress variation in coupling efficiency and to perform adjustment without damaging an optical element and an optical fiber. It is to provide a semiconductor laser module that can be mounted.

[0012]

According to the present invention, there is provided a substrate having a V-groove for fixing an optical fiber, and fixing the optical fiber by covering the substrate with the optical fiber mounted thereon. A fiber cover, wherein the optical fiber is fixed between the substrate and the fiber cover with a curable resin, and the excess fiber of the curable resin is poured into the fiber cover. A semiconductor laser module characterized in that the resin introduction groove is formed.

Further, according to the present invention, in the above-described semiconductor laser module, a semiconductor laser module in which a V-groove for fixing an optical fiber is formed in a fiber cover is obtained.

On the other hand, according to the present invention, in the semiconductor laser module, a semiconductor laser module in which the resin introduction groove extends in a direction parallel to the extending direction of the V groove is obtained.

On the other hand, according to the present invention, in the semiconductor laser module, a semiconductor laser module in which the resin introduction groove extends in a direction perpendicular to the extending direction of the V groove is obtained.

Further, according to the present invention, in any one of the above semiconductor laser modules, the fiber cover
A semiconductor laser module that is V-transparent and the curable resin is UV-curable is obtained.

[0017]

In the semiconductor laser module of the present invention, a V-groove is also formed on a UV-transmitting fiber cover for fixing an optical fiber by covering a Si substrate on which a V-groove for fixing an optical fiber is formed. Since the optical fiber is cured with the UV curable resin between the UV transparent fiber covers, the optical fiber is stabilized at four points by the V groove formed on the Si substrate and the V groove formed on the UV transparent fiber cover. Is held. Further, since the UV transmitting fiber cover is used, the bonding area for fixing the optical fiber is increased, and the optical fiber can be stably fixed on the Si substrate.
This causes the tip of the optical fiber to shift laterally in the direction perpendicular to the optical axis due to the stress of the optical fiber itself, causing the semiconductor laser and the optical fiber to be displaced from the optimal coupling position, resulting in variations in coupling efficiency. The occurrence can be sufficiently suppressed. Further, the UV transmitting fiber cover is formed with a resin introduction groove extending in a direction parallel to or perpendicular to the extending direction of the V groove, and is used to fix the optical fiber and the UV transmitting fiber cover. Since the applied UV curable resin flows into the resin introduction groove, the optical fiber can be stably fixed.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The semiconductor laser module according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the basic structure of a semiconductor laser module according to Embodiment 1 of the present invention. FIG. 1A is a perspective view of an external appearance in which a main part is partially cut away. (B) relates to a cross-sectional view from the front direction. In this semiconductor laser module, a V-groove 1a for fixing an optical fiber 3 is formed on a Si substrate 1 in a direction parallel to an optical axis by anisotropic etching, and the semiconductor laser 2 is fixed by AuSn solder. I have. Here, a single mode fiber having a core diameter of 10 μm and a cladding diameter of 125 μm is used for the optical fiber 3, and the V-groove 1 a is set so that the height of the active layer of the semiconductor laser 2 and the center of the core of the optical fiber 3 coincide. Is formed.

After arranging the optical fiber 3 in the V-groove 1a of the Si substrate 1 near the emitting end of the semiconductor laser 2,
The UV-transparent fiber cover 4A is disposed on the optical fiber 3 coated with the V-curable resin 6. A V-groove 4a for fixing the optical fiber 3 in a direction parallel to the optical axis is formed in the UV transmitting fiber cover 4A. U
The V-curable resin 6 not only flows into the V-grooves 1a and 4a, but also fills the gap between the Si substrate 1 and the UV-transparent fiber cover 4A.

The optical fiber 3 and the UV-transmitting fiber cover 4A apply UV light at an intensity of 60 mW / cm ² for 60 seconds.
It is fixed by irradiating from above the i-substrate 1 to cure the UV-curable resin 6.

The V-groove 4a formed in the UV-transmitting fiber cover 4A has a gap of 50 μm between the UV-transmitting fiber cover 4A and the Si substrate 1 when the optical fiber 3 is fixed.
It is formed so as to have a small gap.

In the case of this semiconductor laser module, the optical fiber 3 comes into contact with the V-groove 1a formed on the Si substrate 1 at two points, and further comes into contact with the V-groove 4a formed on the UV transmitting fiber cover 4A at two points. As a result, a total of four points come into contact with each other and are stably held, so that the displacement can be suppressed. In addition, since the space between the UV transmitting fiber cover 4A and the Si substrate 1 is filled with the UV curable resin 6,
If the V-curable resin 6 is applied so as to spread over the entire surface of the UV-transmitting fiber cover 4A, the bonding area between the UV-transmitting fiber cover 4A and the Si substrate 1 increases, so that the optical fiber 3 is used as the UV-transmitting fiber cover 4A. Thus, it is stably fixed in the vertical and horizontal directions.

With such a configuration, the optical fiber 3 is mounted at the optimum coupling position with the semiconductor laser 2 without causing the tip of the optical fiber 3 to be displaced in the direction perpendicular to the optical axis due to the stress of the optical fiber 3 itself. Become. Further, since the optical fiber 3 is stably fixed in the vertical direction, it is not only resistant to an environmental resistance test, but also does not easily peel off when an upward force is applied in handling in a production process. .

Therefore, this semiconductor laser module has:
By using the UV transmitting fiber cover 4A having the V-groove 4a and the UV curable resin 6, the semiconductor laser 2
In addition, variations in the coupling efficiency of the optical fiber 3 can be reduced.

FIG. 2 shows the basic structure of a semiconductor laser module according to a second embodiment of the present invention. FIG. 2A is a perspective view showing an external perspective view of a main part of which is partially cut away. (B) relates to a cross-sectional view from the front direction. This semiconductor laser module has an excessive UV curing extending in the direction parallel to the optical axis (the direction parallel to the extending direction of the V-groove 4b) on the UV transmitting fiber cover 4B as compared with the semiconductor laser module of the first embodiment. The difference is that a resin introduction groove 7a for pouring the conductive resin 6 is provided, and the mounting method is the same as that of the first embodiment.

If the UV curable resin 6 is excessively applied without the resin introduction groove 7a, the Si substrate 1 and the U
Although the gap of the V-transmitting fiber cover 4B widens and the V-groove 4b formed in the UV-transmitting fiber cover 4B does not come into contact with the optical fiber 3, the optical fiber 3 cannot be stably held. Is present, excess UV curable resin 6 flows into the resin introduction groove 7a, so that the optical fiber 3 is stably held at four points by the V grooves 1a and 4b.

FIG. 3 shows the basic structure of a semiconductor laser module according to a third embodiment of the present invention. FIG. 3 (a) relates to an external perspective view in which a main part thereof is partially cut away. (B) relates to a cross-sectional view from the front direction. This semiconductor laser module has an excessive UV curing extending in the direction perpendicular to the optical axis (the direction perpendicular to the extending direction of the V-groove 4c) on the UV-transmitting fiber cover 4C as compared with that of the first embodiment. The difference is that a resin introduction groove 7b for pouring the conductive resin 6 is provided, and the mounting method is the same as that of the first embodiment.

If the UV curable resin 6 is excessively applied without the resin introduction groove 7b, the Si substrate 1 and the U
Although the gap of the V-permeable fiber cover 4C widens and the V-groove 4c formed in the UV-permeable fiber cover 4C does not come into contact with the optical fiber 3, the optical fiber 3 cannot be stably held. Is present, excess UV curable resin 6 flows into the resin introduction groove 7b, so that the optical fiber 3 is also stably held at the four points by the V grooves 1a and 4c.

[0030]

As described above, according to the semiconductor laser module of the present invention, the V for fixing the optical fiber is fixed.
A V-groove is also formed in the fiber cover that covers the substrate on which the groove is formed and fixes the optical fiber, and a resin that extends in a direction parallel to or perpendicular to the extending direction of the V-groove in the fiber cover. After the introduction groove is formed, the optical fiber is cured and fixed between the substrate and the fiber cover with the curable resin, so that even if the curable resin becomes excessive, it flows into the resin introduction groove, and as a result, the semiconductor laser and the optical Variations in the coupling efficiency of the fiber are sufficiently suppressed, and the optical element and the optical fiber can be mounted without any damage without damage.

[Brief description of the drawings]

FIGS. 1A and 1B show a basic configuration of a semiconductor laser module according to a first embodiment of the present invention, wherein FIG. FIG.

FIGS. 2A and 2B show a basic configuration of a semiconductor laser module according to a second embodiment of the present invention, in which FIG. 2A is an external perspective view in which a main part is partially cut away, and FIG. FIG.

FIGS. 3A and 3B show a basic configuration of a semiconductor laser module according to a third embodiment of the present invention, wherein FIG. FIG.

4A and 4B show a basic configuration of a semiconductor laser module provided in a conventional optical coupling device. FIG. 4A is related to a side view, and FIG. 4B is related to a cross-sectional view from the front.

FIG. 5 is a sectional view showing a basic configuration of a conventional parallel transmission optical module (semiconductor laser module) as viewed from the front.

[Explanation of symbols]

1 Si substrate 1a, 4a, 4b, 4c, 8a, 11a, 11b, 12
a V groove 2 semiconductor laser 3 optical fiber 4A, 4B, 4C UV transmitting fiber cover 5 epoxy resin 6 UV curable resin 7a, 7b, 7c resin introduction groove 8 InP substrate 9 active area 10 guide pin 11 substrate with V groove 12 Holding board

Claims (5)

(57) [Claims] 1. A semiconductor laser module comprising: a substrate on which a V-groove for fixing an optical fiber is formed; and a fiber cover for fixing the optical fiber by covering the substrate with the optical fiber mounted. Wherein the optical fiber is fixed between the substrate and the fiber cover by a curable resin, and the fiber cover has a resin introduction groove for pouring an excess of the curable resin. Characteristic semiconductor laser module. 2. The semiconductor laser module according to claim 1, wherein a V-groove for fixing said optical fiber is formed in said fiber cover. 3. The semiconductor laser module according to claim 2, wherein said resin introduction groove extends in a direction parallel to an extending direction of said V groove. 4. The semiconductor laser module according to claim 2, wherein said resin introduction groove extends in a direction perpendicular to an extending direction of said V groove. 5. The semiconductor laser module according to claim 1, wherein said fiber cover has a U shape.
A semiconductor laser module, which is V-transparent and the curable resin is UV-curable.