JPH0792355A - Optical module device - Google Patents

Abstract

PURPOSE:To suppress the conduction of heat to the juncture of a ferrule and an optical fiber and to enhance the strength of adhesion of the optical fiber without providing the ferrule to be used for optically connecting the optical fiber and an optical semiconductor element with a heat insulating gap. CONSTITUTION:The optical semiconductor element 1 is mounted in a metallic case 6 and the terminal of the optical fiber 9 is fixed into this metallic case 6 by using the ferrule 10 so as to be optically connected to the optical semiconductor element 1. The ferrule 10 is bisected in the longitudinal direction. The first ferrule 10a is fixed into the metallic case 6 and the second ferrule 10b is connected to a coating 9a of the optical fiber 9 by parting this ferrule from the first ferrule 10a and interposing a resin 12 therebetween. The heat at the time of laser welding the first ferrule 10a into the metallic case 6 is insulated by the resin interposed therein and is hardly conducted to the second ferrule 10b any more. Peeling of the connection to the coating 9a of the optical fiber by the heat is thus suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module device using an optical semiconductor element or the like, and more particularly to a ferrule mounting structure used to optically connect an optical fiber to the optical semiconductor element.

[0002]

2. Description of the Related Art An example of a conventional optical module device using an optical semiconductor element is shown in FIG. Here, a laser diode, a light emitting diode, a photodiode, or the like is used as the optical semiconductor element, the optical semiconductor element is bonded onto the heat sink 2 having high thermal conductivity by a metal solder, and the chip carrier 3 having high thermal conductivity is further bonded by the metal solder. Mounted on the metal substrate 4 and fixed integrally on the metal substrate 4. This metal substrate 4 is mounted on a cooling device 5 utilizing the Peltier effect, and is housed inside a metal case 6. Also,
A lens 7 that is optically coupled to the optical semiconductor element is fixed to the metal substrate 4, and is further optically coupled to the optical fiber 9 through the lens 7.

As shown in a partially enlarged view in FIG.
The optical fiber 9 has a coating (secondary coating) 9a made of resin or the like removed at its end portion to form a bare optical fiber 9b. The bare optical fiber 9b is covered with a glass tube or a ceramic tube 11, and further A ferrule 10 'made of a metal such as stainless steel is covered on the outside up to a position where a part of the secondary coating 9a is covered, and these are integrally fixed by an epoxy resin 12. The ferrule 10 'is joined to a ring-shaped stainless material called a slide ring 8 by laser welding, and is fixed to the metal substrate 4 by laser welding via the slide ring 8. Further, the ferrule 10 'is passed through a hole 6a provided on one side of the metal case 6, and is fixed by filling a filler 13 such as metal solder or resin between the ferrule 10' and the metal case 6.

In this optical module, the optical semiconductor element 1 is used.
And the optical fiber 9 are optically connected to each other via the lens 7, and it becomes possible to transmit an optical signal between the optical semiconductor element 1 and the optical fiber 9. Further, by filling the filling material 13 between the ferrule 10 ′ and the metal case 6, the airtightness inside the metal case 6 is secured, and the reliability of the optical coupling between the optical semiconductor element 1 and the optical fiber 9 is improved. .

[0005]

In such a conventional optical module, since the ferrule 10 'made of a metal such as stainless steel is joined to the coating 9a of the optical fiber 9 by the epoxy resin 12, the slide ring 8 is formed.
The heat of laser welding the metal to the metal substrate 4 is the ferrule 1
When it is transmitted to the secondary coating 9a via 0 ', this 2
Since the heat resistant temperature of the secondary coating 9a is as low as about 80 ° C., the heat of the secondary coating 9a cures and the adhesive strength between the secondary coating 9a and the epoxy resin 12 is lowered, and as a result, the optical fiber 9 and the ferrule 10 'are formed. Adhesive strength is reduced. If this adhesive strength is reduced, the optical fiber 9 will move to the ferrule 1.
Moved in 0 ', the position with respect to the lens 7 is moved,
There is a problem that the optical connection with the optical semiconductor element 1 is impaired.

In order to solve this problem, for example, in Japanese Unexamined Patent Publication No. 63-47990, a concentric outer cylinder is provided on a part of the outer surface of the ferrule, and a heat insulating gap is provided between the outer cylinder and the ferrule. It has been proposed to prevent the heat generated during laser welding of the slide ring from being transferred to the ferrule and prevent damage to the ferrule and the optical fiber. However, in order to provide the heat-insulating void, it is necessary to perform boring processing on the ferrule, which makes it difficult to manufacture the ferrule, and the ferrule becomes large in size, and the cost is further increased. An object of the present invention is to provide a ferrule with a heat insulating void,
An object of the present invention is to provide an optical module device capable of increasing the adhesive strength of an optical fiber by suppressing heat transfer to a connecting portion between a ferrule and an optical fiber.

[0007]

According to the present invention, a ferrule for fixing an end of an optical fiber to a metal substrate in a metal case on which an optical semiconductor element is mounted is divided in a length direction, and one of the divided ferrules is used. Is fixed to a metal substrate, and the other ferrule is connected to the coating of the optical fiber. In this case, each of the divided ferrules has a gap in the lengthwise direction, is connected to the optical fiber with a resin, and the resin is interposed in the gap. For example, the ferrule is divided into two in the length direction, the first ferrule is fixed to the metal substrate, and the hole provided in the metal case is inserted and fixed with the filler, and the second ferrule is coated on the optical fiber. Connecting. Alternatively, the ferrule is divided into three parts in the length direction, the first ferrule is fixed to the metal substrate, the second ferrule is inserted through the hole provided in the metal case and fixed by the filler, and the third ferrule is fixed to the optical fiber. Connect to the coating.

[0008]

[Function] The ferrule is divided in the lengthwise direction, arranged with a gap between each other, and resin is interposed in the gap, thereby increasing the thermal resistance between the divided ferrules and fixing one ferrule to the metal substrate. The heat generated at that time is made difficult to be transferred to the other ferrule, and the connection of the coating of the optical fiber connected to the other ferrule is prevented from being peeled off by heat.

[0009]

The present invention will be described below with reference to the drawings. FIG. 1A is a sectional view showing the overall configuration of an embodiment of the present invention. An optical semiconductor element 1 such as a laser diode or a light emitting diode is a heat sink 2 made of a highly heat conductive material.
The above is joined with a metal solder made of gold-silicon alloy, gold-tin alloy, lead-tin alloy, or the like, and further joined on the chip carrier 3 made of a metal having high thermal conductivity such as copper via the metal solder. Then, it is fixed on the metal substrate 4 by metal solder or laser welding. The metal substrate 4 is a metal case 6 by a cooling device 5 utilizing the Peltier effect.
Installed inside. An indium-tin alloy is used as a metal solder for fixing the cooling device 5 to the metal case 6. In addition, a part of the metal substrate 4. A lens 7 is fixed to the optical semiconductor element 1 by a metal solder, and is optically connected to the optical semiconductor element 1. Further, a slide ring 8 made of a ring-shaped metal is laser-welded to the metal substrate 4, and an end portion of an optical fiber 9 inserted through a hole 6a provided on one side of the metal case 6 is slid by a ferrule 10 on the slide ring. 8 and is optically connected to the optical semiconductor element 1 via the lens 7.

FIG. 1B is a detailed sectional view of the optical fiber 9 and the ferrule 10. The secondary coating 9a is peeled off at the end of the optical fiber 9, and the exposed bare optical fiber 9b is covered with the glass tube 11. Further, a ferrule 10 made of stainless is covered on the outer side thereof. The ferrule 10 is composed of first and second ferrules 10a and 10b divided in the length direction, and the relatively long first ferrule 10a is connected to the optical fiber 9
Second ferrule 1 shorter than this
0b is located inside the first ferrule 10a so as to be spaced from the first ferrule 10a and to cover a part of the secondary coating 9a of the optical fiber 9. The optical fiber 9, the glass tube 11, the first and second ferrules 10a and 10b are integrally connected by the epoxy resin 12.

The first ferrule 10a is laser-welded to the slide ring 8 and the slide ring 8
Are laser-welded and fixed to the metal substrate 4. The first ferrule 10a is inserted into a hole 6a provided on the side surface of the metal case 6, and is fixed to the metal case 6 by filling the hole with a filler 13 made of metal solder such as indium or epoxy resin. . The filling operation with the filling material 13 is performed by locally heating the filling portion with a soldering iron in order to prevent the reliability of the module from being lowered due to a temperature rise.

According to this structure, when the slide ring 8 is laser-welded to the metal substrate 4, or when the first ferrule 1 is used.
The heat generated when laser welding 0a to the slide ring 8 is transferred to at least the first ferrule 10a,
The first ferrule 10a is locally heated to 120 to 160 ° C. However, in the present embodiment, the first ferrule 10a and the second ferrule 10b are formed separately, a gap is provided between both ferrules, and the epoxy resin 12 is interposed therebetween, and the heat conduction of stainless steel. The rate is 17 W / mk, while the epoxy resin is about 1 W / mk, which means that the first ferrule 1
0a and the second ferrule 10b have a large thermal resistance, the heat of the first ferrule 10a is difficult to be transferred to the second ferrule 10b. Therefore, the second ferrule 10b and the secondary coating 9a of the optical fiber 9 are prevented. The temperature rise of the connection part with is suppressed.

For this reason, in the prior art, the secondary coating 9a was heated to about 90 ° C. due to heat conduction through the ferrule, whereas in this embodiment, the temperature was raised to only about 65 ° C. Since 9a is usually cured at 80 ° C. or higher, curing of the epoxy resin 12 is prevented, and it is possible to effectively prevent peeling of the adhesive between the epoxy resin 12 and the secondary coating 9a. Thereby, the optical fiber 9 and the second ferrule 10
The adhesive strength of b is improved, and the optical fiber 9 and the optical semiconductor element 1 are
The reliability of the optical connection with can be improved. It should be noted that this effect is obtained by connecting the ferrule 10 to the hole 6 of the metal case 6.
It is similarly effective against the heat when the filler 13 is filled with the filler 13 a.

Incidentally, the measurement results of the adhesive strength between the optical fiber and the ferrule in the present invention and the conventional optical module are shown in FIGS. 4 and 5, respectively. In these figures, (a) shows the strength before connecting the ferrule to the module, and (b) shows the strength after connecting. In addition, the measurement result is the case where the distance between the first ferrule 10a and the second ferrule 10b is 1.0 mm and the outer diameter is 1.5 mm. As can be seen from the measurement results, the conventional optical semiconductor device has about 100
Although the adhesive strength is reduced by 0 g, it is about 10 in the present invention.
Only 0g has dropped. From this, the present invention has an effect of preventing a decrease in the adhesive strength between the optical fiber and the ferrule due to the heat applied at the time of joining with the metal solder or the resin. Therefore, it is possible to maintain a high adhesive strength between the optical fiber and the ferrule without providing a heat insulating void in the ferrule, there is no need to perform boring processing on the ferrule, and it is possible to avoid an increase in the size of the ferrule and a complicated structure of the ferrule, and Cost reduction can be realized.

Next, another embodiment of the present invention will be described with reference to the drawings. 2 (a) is a sectional view of the entire structure, FIG.
(B) is a detailed sectional view of the ferrule part. In this embodiment, only the structure of the ferrule part is different from that of the previous embodiment, so the structure of the ferrule part will be described. here,
The ferrule is divided into three parts in the lengthwise direction.
It is composed of the third ferrules 10A, 10B and 10C. Then, in the optical fiber 9, the bare optical fiber 9b of the terminal from which the secondary coating 9a has been peeled off is covered with the glass tube 11, and the first, second and third ferrules 10A, 10 are provided on the outside thereof.
B and 10C are covered with a gap in the length direction, and each ferrule is fixed by an epoxy resin 12. In this case, the second ferrule 10B has a hole 6a in the metal case 6.
The third ferrule 10C is disposed at a position corresponding to the above, and a part of the third ferrule 10C is disposed so as to cover the secondary coating 9a.

In this structure, the first ferrule 10A is joined to the stainless slide ring 8 by laser welding and further connected to the metal substrate 4. The second ferrule 10B is fixed in the hole 6a of the metal case 6 with a filler. Therefore, the first ferrule 1
Since a gap is defined between 0A and the second ferrule 10B, and the epoxy resin 12 is present between the two, the thermal resistance becomes large, and at the time of laser welding the first ferrule 10A and the slide ring 8. The heat generated is the first
Even when the heat is transferred to the ferrule 10A, the heat is
Transmission to the ferrule 10B is suppressed. Therefore, the heat transfer to the third ferrule 10C having a gap between the second ferrule 10B and the epoxy resin 12 is extremely small. As a result, the temperature rise in the secondary coating 9a of the optical fiber 9 becomes smaller than that in the above-mentioned embodiment, and the optical fiber 9 and the third coating 9a
The adhesive strength of the ferrule 10C is hard to be lowered.

The heat generated when the second ferrule 10C is fixed in the hole 6a of the metal case 6 by the filler 13 is the second heat.
Even when the heat is transferred to the ferrule 10B, the heat transfer in the third ferrule 10C is suppressed, the temperature rise of the secondary coating 9a is prevented, and the optical fiber 9 and the third ferrule 10C are bonded for the same reason as in the above-described embodiment. The strength is hard to be lowered. In this embodiment, the decrease in the adhesive strength between the optical fiber 6 and the third ferrule 10C before and after the laser welding and the filling of the filler is 100 g or less. Further, in this embodiment as well, it is not necessary to provide a heat insulating space in the ferrule, and it is possible to avoid the ferrule from becoming large in size and the structure from becoming complicated, and to reduce the cost.

[0018]

As described above, according to the present invention, the ferrule for fixing the end of the optical fiber is divided in the length direction on the metal substrate in the metal case on which the optical semiconductor element is mounted,
Since one of the divided ferrules is fixed to the metal substrate and the other ferrule is connected to the coating of the optical fiber,
It increases the thermal resistance between the divided ferrules, making it difficult for the heat generated when one ferrule is fixed to the metal substrate or metal case to be transferred to the other ferrule, and to prevent the coating of the optical fiber connected to the other ferrule. Prevents the connection from peeling off due to heat. As a result, there is an effect that the connection strength can be increased without forming a heat insulating void in the ferrule, and the ferrule can be prevented from becoming large, complicated, and high in cost. Further, by inserting a resin in the space between the divided ferrules, the thermal resistance between them can be further increased, and the connection strength of the optical fiber can be further increased.

[Brief description of drawings]

1A and 1B show an embodiment of an optical module device of the present invention, in which FIG. 1A is a sectional view showing the entire structure, and FIG. 1B is an enlarged sectional view of a ferrule part.

2A and 2B show another embodiment of the present invention, in which FIG. 2A is a sectional view showing the entire structure, and FIG. 2B is an enlarged sectional view of a ferrule part.

FIG. 3 shows an example of a conventional optical module device,
(A) is sectional drawing which shows the whole structure, (b) is an expanded sectional view of a ferrule part.

FIG. 4 is a diagram showing the bonding strength between an optical fiber and a ferrule in one embodiment of the present invention, (a) is the strength before laser welding, and (b) is the strength after laser welding.

5A and 5B are diagrams showing the bonding strength between an optical fiber and a ferrule in a conventional optical module device, where FIG. 5A is the strength before laser welding and FIG. 5B is the strength after laser welding.

[Explanation of symbols]

 1 Optical Semiconductor Element 3 Chip Carrier 4 Metal Substrate 6 Metal Case 8 Slide Ring 9 Optical Fiber 9a Secondary Coating 10 (10a, 10b, 10A to 10C) Ferrule 11 Glass Tube 12 Resin 13 Filler

Claims (4)

[Claims] 1. An optical semiconductor element mounted on a metal substrate in a metal case, and an optical fiber whose terminal is fixed to the metal substrate so as to be optically connected to the optical semiconductor element, In an optical module device in which the end of the optical fiber is covered with a metal ferrule and fixed to the optical fiber with resin, and the ferrule is fixed to the metal substrate by welding or the like, the ferrule is divided in the length direction. An optical module device characterized in that one of the divided ferrules is fixed to a metal substrate, and the other ferrule is connected to a coating of an optical fiber. 2. The optical module device according to claim 1, wherein each of the divided ferrules is connected to the optical fiber with a resin having a gap in the lengthwise direction, and a resin is interposed in the gap. 3. The ferrule is divided into two parts in the length direction, and the first part
3. The optical module device according to claim 1, wherein said ferrule is fixed to a metal substrate, and a hole provided in a metal case is inserted and fixed by a filler, and the second ferrule is connected to the coating of the optical fiber. 4. The ferrule is divided into three parts in the length direction, and the first part
The ferrule of No. 3 is fixed to the metal substrate, the second ferrule is inserted through the hole provided in the metal case, and fixed with the filling material.
3. The optical module device according to claim 1, wherein the ferrule is connected to a coating of an optical fiber.