JPH0652819B2 - Optical coupling device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an optical coupling device used for optical communication, which couples emitted light of a semiconductor laser to an optical fiber.

[Conventional technology]

FIG. 3 and FIG. 4 show a conventional semiconductor laser and optical fiber optical coupling device. The semiconductor laser device 1 is fixed on the chip carrier 2. Optical fiber 3
A solder a4 is filled in the periphery of the laser coupling portion 6, and the tip of the optical fiber 3 is axially fixed and fixed on the chip carrier 2 so as to face the light emitting portion 5 of the semiconductor laser element 1, thereby forming a laser coupling portion 6. . As shown in FIG. 3, the laser coupling portion 6 is hermetically sealed in the package 7, and the optical fiber 3 passes through the side surface of the package 7 and the end opposite to the side facing the semiconductor laser element 1 is outside the package 7. The optical fiber 3 is fixed to the side surface of the package 7.

Next, a method of fixing the optical fiber 3 will be described. First, the solder a4 is heated by the soldering iron 8 to a temperature equal to or higher than the melting point of the solder a4 and melted so that the optical fiber 3 can freely move in the solder a4. In this state, the optical fiber 3 is held and the alignment of the optical fiber 3 is adjusted in order to efficiently combine the optical fiber 3 and the emitted light 9 of the semiconductor laser element 1. The adjustment work is completed at the position where the coupling efficiency is maximized, and the soldering iron 8 is separated from the solder a4. The temperature of the solder a4 is lowered and hardened so that the optical fiber 3 is fixed on the chip carrier 2.

Here, in many cases, the surface of the optical fiber 3 is coated with a metal thin film in order to increase the adhesive force with the solder a4. Further, the tip of the optical fiber 3 is often processed into a spherical shape in order to efficiently couple the emitted light 9 of the semiconductor laser element 1.

As described above, the laser coupling portion 6 in which the semiconductor laser device 1 and the optical fiber 3 are optically coupled and fixed on the chip carrier 2 is hermetically sealed in the package 7. Optical fiber 3 and chip carrier 2 in package 7
Since the optical fiber 3 and the package 7 are fixed to each other, the external force applied to the optical fiber 3 outside the package 7 is small between the package 7 and the chip carrier 2 because the rigidity of the optical fiber 3 is small. Therefore, the optical fiber 3 is absorbed by being bent or deformed.
Therefore, the external force applied to the optical fiber 3 outside the package 7 is not applied to the fixing part of the optical fiber 3 and the solder carrier 2 of the chip carrier 2 and the position where the optical fiber 3 finishes the alignment adjustment by the external force. There is no deviation from it.

[Problems to be solved by the invention]

Since the conventional optical coupling device for the semiconductor laser element and the optical fiber is configured as described above, the soldering iron 8 is used to cool the solder a4 when fixing the optical fiber 3 to the chip carrier 2. When it is pulled away from the solder a4, the solder a4 is dragged by the soldering iron 8 as shown in FIG. 4, and thus the optical fiber 3 for which the alignment adjustment is completed is bent and deformed due to the stress of the solder a4. There is a problem that the solder a4 is hardened in a state where the position of the optical fiber 3 is displaced from the position where the coupling efficiency is maximum, and the optical fiber 3 is fixed on the chip carrier 2.

The present invention has been made to solve the above problems, the bending of the optical fiber due to the drag of the solder, eliminating the deformation to efficiently couple the light-emitting semiconductor element and the optical fiber, the package of For external force applied to the optical fiber outside, like the conventional device,
Optical coupling that uses the bending and deformation of the optical fiber to absorb the above external force and prevent the external force from being applied to the fixed part of the optical fiber and the chip carrier, thus maintaining good coupling efficiency between the optical fiber and the semiconductor laser device. The purpose is to obtain the device.

[Means for solving problems]

The optical coupling device according to the present invention is such that when the optical fiber sealed in the package is fixed, the optical fiber does not bend due to stress applied from solder and does not deform. , A cover made of a material having a high rigidity so as to cover the optical fiber is fixed to the portion to be soldered where the optical fiber is in contact with the solder by using solder, and the alignment of the optical fiber to which the cover is fixed is aligned. The adjustment, the fixing of the optical fiber to the chip carrier, and the fixing of the optical fiber package are performed. [Operation] The optical coupling device according to the present invention bends with respect to the stress applied from the solder and does not deform. A cover made of a material with a high rigidity is provided to cover the circumference of the optical fiber, and this cover is held to adjust the optical fiber axis alignment. Since the optical fiber is fixed to the chip carrier, the cover and the optical fiber are not affected by the stress applied to the optical fiber from the solder caused by separating the soldering iron when fixing the optical fiber to the chip carrier with solder. No bending or deformation. Therefore, the optical fiber can be fixed to the chip carrier while keeping the position where the axial alignment adjustment of the optical fiber is completed.

Since the optical fiber inserted into the package from the outside is fixed at two points, the fixing part with the cover and the fixing part with the side surface of the package, the external force applied to the optical fiber outside the package is different from the conventional device. Similarly, the optical fiber is absorbed by bending or deformation between the fixing portion of the cover and the fixing portion of the package side surface. Therefore, no external force is transmitted from the outside of the package to the fixed part of the optical fiber and the cover and the fixed part of the cover and the chip carrier by the external force to the optical fiber outside the package, and The optical fiber will not be displaced from the position where the alignment adjustment of the fiber and the light emitting semiconductor element is completed.

〔Example〕

As an example of the present invention, a case where a stainless steel cylindrical cover is used as the cover (hereinafter, abbreviated as SUS cover) will be described.

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing a laser coupling portion of the embodiment of the present invention.
In the figure, 1 to 9 are the same as the conventional device.

A semiconductor laser device 1 as a light emitting semiconductor device is fixed in advance to a chip carrier 2. Further, the SUS cover 10 has such a structure that the portion where the optical fiber 3 and the solder a4 are in contact with each other in the conventional device covers the periphery of the optical fiber 3 and is fixed in advance by using the solder b11.
Needless to say, the melting point of the solder b11 separating the cover 10 and the package 7 is higher than the melting point of the solder a4, and the soldering iron 8 is lower than the melting point of the solder b11 and higher than the melting point of the solder a4.

Next, a method of fixing the optical fiber 3 to the chip carrier 2 will be described. First, the soldering iron 8 is brought into contact with the solder a4 to melt the solder a4 so that the SUS cover 10 and the optical fiber 3 can freely move in the solder a4. In this state, the SUS cover 10 is held, the position of the optical fiber 3 is adjusted, and stopped at the position where the coupling between the emitted light 9 of the semiconductor laser device 1 and the optical fiber 3 is best. afterwards,
The soldering iron 8 is separated from the soldering a4 to cure the soldering a4, but at this time, the soldering a4 is dragged by the soldering iron 8 and at the same time, the stress due to the soldering a4 is applied to the SUS cover 10. However, since the SUS cover 10 is a material having a high rigidity so as not to be bent or deformed by the stress from the solder a4, the optical fiber 3 may be bent,
No deformation occurs. Therefore, the position of the optical fiber 3 is kept at the position where the above-mentioned axis alignment adjustment is finished, and the solder a4
Is cured, and the optical fiber 3 can be fixed to the chip carrier 2.

The laser coupling portion 6 in which the semiconductor laser element 1 and the optical fiber 3 are optically coupled and fixed on the chip carrier 2 as described above is hermetically sealed in the package 7, and the laser coupling of the optical fiber 3 is performed through the side surface of the package 7. The end opposite to the portion 6 is taken out of the package 7, and the optical fiber 3 is fixed to the side surface of the package 7. In the package 7, the optical fiber 3 is fixed at two points, a fixed part with the SUS cover 10 and a fixed part with the side surface of the package 7. Therefore, when an external force is applied to the optical fiber 3 outside the package 7, The above external force is SUS cover 10
Also, it is absorbed by the bending or deformation of the optical fiber 3 between the optical fiber 3 and the side surface of the package 7, and the fixed portion of the optical fiber 3 and the SUS cover 10 and the SUS cover 10 and the chip carrier 2 are absorbed.
The external force is not transmitted to the fixed part of. Therefore, the position of the optical fiber 3 with respect to the semiconductor laser element 1 does not deviate from the position where the axial alignment of the optical fiber 3 is completed due to the external force on the optical fiber 3 inside the package 7.

Incidentally, it is desirable to apply a metal thin film coating to the surface of the optical fiber 3 in order to increase the adhesive force with the solder. Further, in order to efficiently couple the light emitted from the optical fiber and the semiconductor laser element, it is desirable to process the tip of the optical fiber into a spherical shape.

In the above embodiment, the case where the optical fiber and the SUS cover are fixed by using the solder has been described, but the same effect of the invention can be obtained when the optical fiber and the SUS cover are fixed by using the adhesive.

Further, in the above embodiment, the case where a stainless steel cylindrical cover is used as the cover has been described, but when a stainless steel cover having another shape, another metal cover, a ceramic cover, or a glass cover is used. Also, the same effect of the invention can be obtained.

In the above embodiments, the case where the semiconductor laser device is used has been described, but it goes without saying that the same effects of the invention can be obtained when another light emitting semiconductor device such as a light emitting diode is used.

Further, although the case where the emitted light of the semiconductor laser element is directly coupled to the optical fiber has been described in the above embodiment, the same effect of the invention can be obtained when an optical system such as a lens is arranged between the semiconductor laser element and the optical fiber. It goes without saying that you can get

〔The invention's effect〕

As described above, according to the present invention, in the optical coupling device in which the optical fiber is fixedly supported on the chip carrier and the side surface of the package, the soldered portion of the optical fiber to the chip carrier has a higher rigidity than the optical fiber. The optical fiber is aligned with the light-emitting semiconductor element on the chip carrier by being fixed by soldering with a large cover, and the cover is fixed on the chip carrier with a solder having a lower melting point than the solder fixed on the optical fiber. Since the optical fiber is fixedly supported on the chip carrier and the side surface of the package, the external force applied to the optical fiber from the outside of the package is generated between the two points on the chip carrier and the side surface of the package. It can be absorbed by bending or deforming the optical fiber, and prevents the optical fiber from shifting due to external force. Door can be. Also, by covering the optical fiber with a cover whose rigidity is higher than that of the optical fiber, the optical fiber will not be displaced by soldering after the axis alignment, and by fixing the optical fiber and the cover by soldering, the axis alignment The optical fiber does not shift in the axial direction on the chip carrier later, and by further lowering the melting point of the solder fixing the cover and the chip carrier than the melting point of the solder fixing the optical fiber and the cover,
When the cover is soldered on the chip carrier, there is an effect that the solder fixing the optical fiber and the cover can be prevented from melting.

[Brief description of drawings]

1 is a perspective view showing an optical coupling device according to an embodiment of the present invention, FIG. 2 is a sectional view of a laser coupling portion of the same device, FIG. 3 is a perspective view showing a conventional optical coupling device, and FIG. FIG. 4 is a sectional view of a laser coupling portion of the conventional device. In the figure, 1 is a light emitting semiconductor element, 2 is a chip carrier, 3 is an optical fiber, 4 is a solder a, 5 is a light emitting part, 6 is a laser coupling part, 7 is a package, 8 is a soldering iron, 10 is a cover, and 11 is a cover. Solder b. In the drawings, the same or corresponding parts are designated by the same reference numerals.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshio Miyake, 325 Kamimachiya, Kamakura City, Kanagawa Prefecture, Mitsubishi Electric Corporation, Information Electronics Research Laboratory (72) Inventor, Toshio Takei, 325, Kamimachiya, Kamakura City, Kanagawa Information, Mitsubishi Electric Corporation Electronic Research Laboratory (56) References JP 59-29482 (JP, A) JP 60-43889 (JP, A)

Claims (3)

[Claims] 1. A light-emitting semiconductor element is optically coupled to an optical fiber, and an optical coupling portion fixed on a chip carrier is hermetically sealed in a package, and the optical fiber is penetrated to a side surface of the package. In the fixedly supported optical coupling device, a soldered portion of the optical fiber with respect to the chip carrier is covered by soldering and fixing with a cover having a rigidity higher than that of the optical fiber, and the optical fiber is the light emitting semiconductor element. The optical coupling device, wherein the cover is axially aligned and is fixed on the chip carrier with a solder having a melting point lower than that of the solder fixed to the optical fiber. 2. The optical coupling device according to claim 1, wherein the cover is made of ceramic. 3. The optical coupling device according to claim 1, wherein the cover is made of glass.