JPH07253525A - Optical semiconductor module and its production - Google Patents

Abstract

PURPOSE:To reduce the number of constituting parts or cost while maintaining high optical coupling efficiency and to suppress the variation in the overall length of a module to a lower level. CONSTITUTION:This module has a semiconductor light emitting element 4, a cylindrical holder 8 and a receptacle 10. The spacing between the optical semiconductor element 4 inserted into the cylindrical holder 8 and a lens 6 fixed into the cylindrical holder 8 is adjusted within the cylindrical holder 8. A ferrule 26 inserted and fixed with one end edge of an optical fiber 24 is inserted into a recessed part 28 of the receptacle 10. The receptacle 10 and the cylindrical holder 8 are slid and aligned in a radial direction in a butt position 35 and are welded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor module for optical fiber communication, which focuses light emitted from a semiconductor light emitting element and guides it to an optical fiber, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In an optical semiconductor module for optical fiber communication that focuses light emitted from a semiconductor light emitting element and guides it to an optical fiber, the optical coupling efficiency between the semiconductor light emitting element and the optical fiber is improved and In addition to the simplification of the structure, making the axial length uniform is an important issue.

In a conventional optical semiconductor module, a receptacle is coaxially provided on a cap-shaped holder incorporating a semiconductor light emitting element and a rod type lens via a connecting ring. Then, the ferrule fixed by inserting one end edge of the optical fiber is inserted into the recessed portion of the outer end surface of the receptacle.

Such an optical semiconductor module is manufactured by the following method. That is, after the semiconductor light emitting element and the lens are assembled in a cap-shaped holder, the tip of this holder is inserted into one end of the coupling ring. Then, the ferrule fixed by inserting one end edge of the optical fiber is inserted into the recessed portion of the outer end face of the receptacle, and then the holder and the ring are relatively moved in the axial direction and positioned, Both are laser-welded at their joints. Further, after the ring and the receptacle are relatively moved and positioned at the joint surface, both are laser-welded at the joint surface. An optical semiconductor module having such a configuration is disclosed in Japanese Patent Application Laid-Open No. 3-233415.

[0005]

However, in the conventional optical semiconductor module constructed as described above, a cap-shaped holder and a ring are used to hold the semiconductor light emitting device, the lens and the optical fiber at predetermined predetermined positions. And requires 3 parts of the receptacle. Further, the relative position between the semiconductor light emitting element and the lens is uniquely determined when both are assembled in the holder. Therefore, in order to allow the light emitted from the semiconductor light emitting element to efficiently enter the light receiving surface of the optical fiber, the fixed position between the holder and the coupling ring is axially adjusted to adjust the distance from the holder to the receptacle. I had to adjust. This changes the axial length of the optical semiconductor module, resulting in variations in the outer shape of the optical semiconductor module.

An object of the present invention is to provide an optical semiconductor module capable of eliminating variations in the axial length of the optical semiconductor module and enhancing the optical coupling efficiency between the semiconductor light emitting element and the optical fiber.

[0007]

According to the present invention, in order to achieve the above-mentioned object, a semiconductor light emitting element, a lens for focusing light emitted from the semiconductor light emitting element, the semiconductor light emitting element and the lens are provided. In order to keep the distance between the two members at a predetermined value, the cylindrical holder that coaxially inserts the two members and the recessed portion for supporting the ferrule fixed by inserting one end edge of the optical fiber are removed. And a receptacle having an end surface, wherein the inner end surface of the receptacle is
An optical semiconductor module is provided, which is coaxially butted and fixed to the end surface of the cylindrical holder on the lens side.

Here, the cylindrical holder has a first cylindrical body in which the semiconductor light emitting element is inserted and fixed, a second cylindrical body in which a lens is inserted and fixed, and between the first and second cylindrical bodies. And a third cylindrical body having a protrusion protruding in the axial direction at the other end by interposing one end edge thereof, and the inner end surface of the receptacle has a recess for receiving the protrusion. be able to. In addition, a cylindrical portion integrally formed with the lens on the peripheral edge of the lens may be in contact with the semiconductor light emitting element. Further, the outer peripheral surface of the receptacle may have a wedge-shaped constricted portion near the inner end surface. At least one of the cylindrical holder and the receptacle may be made of ferritic stainless steel containing 0.05% by weight or less of sulfur. Also,
At least the inner surface of the receptacle may be made of ceramics. Further, the optical axis of the light focused by the lens may intersect with the central axis of the receptacle. Further, the protrusion of the third cylinder of the cylindrical holder may be in contact with the bottom surface of the recess of the receptacle.

Further, a semiconductor light emitting element having a built-in optical semiconductor chip and a light guide provided on the light emitting surface side thereof, a lens for focusing light emitted from the semiconductor light emitting element, and the lens are inserted through the lens. Tubular holder fixed by
A receptacle having a recessed portion on an outer end surface for supporting a ferrule fixed by inserting one end edge of an optical fiber, and an inner end surface of the receptacle is coaxially butted against one end surface of the cylindrical holder to be fixed. An optical semiconductor module is provided.

Here, the light guide may include a disk, two main surfaces of the disk are covered with an antireflection film, and side peripheral surfaces thereof are covered with a reflection film.

Furthermore, a step of fixing the light focusing lens in the cylindrical holder, a step of inserting the semiconductor light emitting element in the cylindrical holder, and a ferrule fixed by inserting one end edge of the optical fiber. The step of inserting into the concave portion of the outer end surface of the receptacle, the step of coaxially abutting the inner end surface of the receptacle on the one end surface of the cylindrical holder, and the light emitted from the semiconductor light emitting element by the lens Adjusting the distance from the semiconductor light emitting element to the lens to fix the semiconductor light emitting element in the cylindrical holder so that the light is condensed on the light receiving surface of the optical fiber; and the cylindrical holder and the receptacle. And a step of fixing the receptacle to the holder by relatively aligning the optical axis of the optical axis.

Here, a cylindrical portion integrally formed with the lens on the periphery of the lens is brought into contact with the semiconductor light emitting element, and the distance from the semiconductor light emitting element to the lens can be set to a predetermined value. .

[0013]

According to the present invention, the distance between the semiconductor light emitting element and the lens is adjusted in the cylindrical holder, and the deviation between the optical axis of the light focused by the lens and the optical axis of the optical fiber is determined by the cylindrical holder. Since the adjustment is performed by the abutting surface of the optical semiconductor module and the receptacle, it is possible to eliminate variations in the total length of the optical semiconductor module due to these adjustments. Further, basically, only two points, that is, the cylindrical holder and the receptacle, are sufficient as the housing component, so that the configuration can be simplified and the cost can be reduced. It should be noted that the distance adjustment for maximizing the degree of optical coupling requires a smaller amount of adjustment by adjusting the distance from the semiconductor light emitting element to the lens than by adjusting the distance from the lens to the tip of the optical fiber. .

Further, by forming a projection portion projecting in the axial direction on the end surface of the cylindrical holder on the receptacle side and providing a concave portion on the inner end surface of the receptacle for receiving the projection portion, dust generated by welding or the like is removed. Adhesion to the lens can be prevented.

Further, by providing the wedge-shaped constricted portion on the outer peripheral surface of the receptacle, welding at the abutting surface between the cylindrical holder and the receptacle can be reliably achieved in a short time.

Further, by using ferritic stainless steel containing 0.05% by weight or less of sulfur for at least one of the cylindrical holder and the receptacle, not only the workability can be improved but also cracks at the time of welding can be obtained. Occurrence can be prevented.

Further, by constructing the optical axis of the light focused by the lens so as to intersect the central axis of the receptacle, it is possible to prevent the light reflected at the tip of the optical fiber from entering the optical semiconductor element. be able to.

[0018]

Embodiments of the present invention will now be described with reference to the drawings.

(Embodiment 1) An optical semiconductor module 2 shown in FIG. 1 includes a semiconductor light emitting element 4, a focusing lens 6, a cylindrical holder 8 into which the semiconductor light emitting element 4 and the lens 6 are coaxially inserted, and a receptacle. 10 and 10. The semiconductor light emitting element 4 has an optical semiconductor chip 12 formed of a laser diode, a protective cap 14 covering the same, and a disc-shaped stem 16. The optical semiconductor chip 12 is fixed on the stem 16 via a mount 18. ing. Protective cap 1
4 is also fixed to the stem 16. Optical semiconductor chip 12
Light emitted from the glass is taken out through a glass window 20 provided in the protective cap 14. The stem 16 and the mount 18 are made of an iron-based metal and have a gold plating layer on the surface. Terminal pins 22 are connected to the optical semiconductor chip 12. A submount (not shown) made of silicon or the like may be interposed between the optical semiconductor chip 12 and the mount 18. The lens 6 is made of glass with an NA of 0.5 formed on an aspherical surface and has an antireflection film on its surface.

The receptacle 10 has a recess 28 for supporting a ferrule 26 formed by inserting one end edge of an optical fiber 24. The cylindrical holder 8 has a large-diameter portion 30 accommodating the protective cap 14 and the stem 16 of the semiconductor light-emitting element 4, and a small-diameter portion 32 integrally connected to the large-diameter portion 30. The lens 6 is inserted and fixed. Since the large-diameter portion 30 has an inner diameter slightly larger than the outer diameter of the stem 16, at the time of assembly, the stem 16
Can be moved in the large-diameter portion 30 in the axial direction, and the distance between the lens 6 and the semiconductor light emitting element 4 is adjusted by this movement. The stem 16 and the large-diameter portion 30 after the distance adjustment are
Laser welded at position 34. Further, the small diameter portion 32 of the cylindrical holder 8 has a wall thickness of about 2 mm, and the smooth outer end surface and the inner end surface of the receptacle 10 are located at the position 35.
Butt and laser welded.

The light emitted from the optical semiconductor chip 12 of the semiconductor light emitting element 4 is passed through the lens 6 to the end face 3 of the optical fiber 24.
In order to efficiently enter the optical semiconductor chip 6, the optical semiconductor chip 1
2. It is important to adjust the alignment of the lens 6 and the one end surface 36 of the optical fiber 24. As shown in FIG. 2, the distance between the optical semiconductor chip 12 and the lens 6 is L1, the distance between the lens 6 and the optical fiber 24 is L2, and the amount of deviation between the optical axis of the lens 6 and the optical axis of the optical semiconductor chip 12 is set. Is L3, and the amount of deviation between the optical axis of the lens 6 and the optical axis of the optical fiber 24 is L4,
The optical coupling efficiency between the optical semiconductor chip 12 and the optical fiber 24 is represented by the characteristics shown in FIGS. The optical fiber 24 used to measure this characteristic has a core diameter of 50
It was a μm multimode fiber.

As can be seen from FIGS. 3 and 4, 80%
About 200 μm for L2 to obtain the above optical coupling efficiency
There is an allowable range of (about 5.64 mm to about 5.84 mm). On the other hand, in L1, about 60 μm (± about 30 μm
There is only the allowable range of m). This means that when L2 is adjusted to obtain an optical coupling efficiency of 80% or more and an optical semiconductor module is manufactured, the total length of the optical semiconductor module varies within a range of about ± 100 μm. On the other hand, in order to obtain an optical coupling efficiency of 80% or more, L
When the optical semiconductor module is manufactured by adjusting No. 1, the variation in the total length is within the range of about ± 30 μm.

Therefore, if L1 is adjusted to manufacture an optical semiconductor module, it is possible to suppress variations in the total length M1 shown in FIG. After adjusting L1, Y
Each part must be fixed to each other by welding using an AG laser, but a positional deviation of about ± 5 μm occurs during welding. Since the positional deviation at the time of welding is sufficiently smaller than the allowable range of L1 described above, even if the adjustment position of L1 is deviated by welding, it will be within the allowable range, and an optical coupling efficiency of 80% or more can be obtained. . On the other hand, also on the side of the semiconductor light emitting element 4, since the stem 16 and the cap 14 are completely inserted into the large diameter portion 30 of the cylindrical holder 8, the length M2 of the optical semiconductor module excluding the terminal pin 22 is set.
Becomes a constant value without being influenced by the above-mentioned adjustment.

Next, the relationship between the positional deviation (axial deviation) of the lens in the direction perpendicular to the optical axis and the optical coupling efficiency will be considered as follows. That is, L3 and L4 for obtaining the optical coupling efficiency of 80% or more are shown in FIGS.
About 12 μm (± 6 μm) and about 34 μm
Each tolerance range is (± 17 μm). Considering that a positional deviation of about ± 5 μm occurs during welding as described above, the allowable range of L3 cannot be said to be sufficiently larger than the positional deviation during welding. Therefore, it is more advantageous to adjust L4 to manufacture an optical semiconductor module.

When the above-described optical path adjustment is performed in the optical semiconductor module 2 shown in FIG. 1, L1 is adjusted by adjusting the distance in which the semiconductor light emitting element 4 and the lens 6 are relatively moved within the cylindrical holder 8. In addition, L4 is adjusted by adjusting the axial displacement in which the cylindrical holder 8 and the receptacle 10 are relatively moved at their abutting surfaces.

Next, the method for manufacturing the optical semiconductor module 2 will be described in detail. First, the small diameter portion 3 of the cylindrical holder 8 is first described.
The lens 6 is inserted into 2 and fixed. Next, the semiconductor light emitting element 4 is inserted into the large diameter portion 30 of the cylindrical holder 8. Further, the ferrule 26 formed by inserting one end edge of the optical fiber 24 is inserted into the recessed portion 28 of the receptacle 10. Next, the optical semiconductor chip 12 of the semiconductor light emitting element 4 is caused to emit light while the outer end surface of the small diameter portion 32 and the inner end surface of the receptacle 10 are held in abutment with each other. Optical fiber 2
The stem 16 of the semiconductor light emitting device 4 is positioned in the large diameter portion 30 while measuring the intensity of the light incident on the position 4.
Is welded with a YAG laser. Next, the cylindrical holder 8 and the receptacle 10 are moved and positioned in the direction perpendicular to the optical axis at their abutting surfaces, and then the position 3
The welding in 5 is performed with a YAG laser.

In the optical semiconductor module 2 of this embodiment, the variation in the total length of the optical semiconductor module 2 can be suppressed to be small without lowering the manufacturing yield. Moreover, since only two housing components are required, the manufacturing process can be simplified, the optical path can be easily adjusted, and an optical semiconductor module with high optical coupling efficiency can be obtained.

(Embodiment 2) The optical semiconductor module 42 in the embodiment shown in FIG. 7 is partly common to the optical semiconductor module 2 in Embodiment 1, and the common components are designated by the same reference numerals. There is. The optical semiconductor module 42 is
Semiconductor light emitting element 4, focusing lens 44, cylindrical holder 46
The lens 44 made of plastic and the receptacle 48 has a cylindrical portion 50 integrally formed on the periphery thereof.
have. The tubular portion 50 is sandwiched and held between a concave portion 52 provided on the lower surface of the top plate portion of the tubular holder 46 and the protective cap 14 of the semiconductor light emitting element 4. The cylindrical portion 50 functions as a spacer that defines the distance between the lens 44 and the semiconductor light emitting element 4, and the light emitted from the semiconductor light emitting element 4 is condensed by the lens 44 on the light receiving surface of the optical fiber 24. Its height is adjusted.

Specifically, after forming the lens 44 having the tubular portion 50 having a predetermined height, the height of the tubular portion 50 is gradually reduced and the distance between the semiconductor light emitting element 4 and the lens 44 is appropriately adjusted. Adjust to a suitable value. After that, the stem 16 and the cylindrical holder 46 are welded at the position 54 while pressing the semiconductor light emitting element 4 against the cylindrical portion 50. According to this method, the semiconductor light emitting element 4 at the time of welding has the tubular holder 4 through the tubular portion 50.
Since it is fixed to No. 6, the positional deviation during welding is slight.

Further, since the concave portion 52 provided on the lower surface of the top plate portion of the cylindrical holder 46 supports the upper edge of the cylindrical portion 50, the coaxiality between the lens 44 and the cylindrical holder 46 becomes good. In addition, there is an advantage that the lens 44 can be easily fixed and that the lens 44 itself is not directly stressed.

The receptacle 48 and the cylindrical holder 46 are joined in the same manner as in the first embodiment. A wedge-shaped constricted portion 58 is formed on the outer peripheral surface of the receptacle 48 so that a cone whose bottom surface is the abutting surface 56 with the cylindrical holder 46 is formed. Therefore, position 6
When laser welding is performed at an angle of 0, the receptacle 48 and the cylindrical holder 46 can be joined satisfactorily in a short time without substantially lowering the mechanical strength.

(Embodiment 3) The optical semiconductor module 62 in the embodiment shown in FIG. 8 is partly common to the optical semiconductor module 42 in the embodiment 2, and the common components are designated by the same reference numerals. is there. This optical semiconductor module 62
Differs from the optical semiconductor module 42 of the second embodiment in the shape of the lens 64. The lens 64 made of plastic has a cylindrical skirt portion 66 integrally formed on the peripheral edge thereof and a projection portion 68 projecting in the axial direction, and the projection portion 68 enters the recess 52 of the cylindrical holder 46. . The lens 64 is sandwiched and held by the top plate portion of the cylindrical holder 46 and the stem 16 of the semiconductor light emitting element 4. The skirt portion 66 functions as a spacer that defines the distance between the semiconductor light emitting element 4 and the lens 64. The distance between the semiconductor light emitting element 4 and the lens 64 is adjusted by gradually cutting the height of the skirt portion 66, and the stem 16 and the cylindrical holder 46 are welded at the position 72. By using the lens 64 having such a structure, the optical semiconductor chip 12 is independent of the height of the cap 14 of the semiconductor light emitting device 4.
The distance between the lens and the lens 64 can be adjusted to an optimum value. As in the second embodiment, the receptacle 70 and the holder 46 are welded to each other at the position 74 after adjusting the axial deviation.

(Embodiment 4) An optical semiconductor module 82 according to the embodiment shown in FIG. 9 is fixed by inserting a first cylindrical body 84 into which the semiconductor light emitting element 4 is inserted and fixed and an aspherical lens 6 into place. The second cylindrical body 94 made of ferrous metal, and the first and second
Third cylindrical body 8 having a lower end interposed between the cylindrical bodies 84 and 94 of the
6 and 6 form a cylindrical holder, to which the receptacle 88 is joined. The stem 16 of the semiconductor light emitting device 4 and the first cylindrical body 84 are spot-welded with a YAG laser at a position 90. The upper end edge 92 of the first tubular body 84 is formed to be thin with a thickness of about 0.2 mm over a width of about 1 mm. On the other hand, the second tubular body 94 has the hole 9 of the third tubular body 86.
It is inserted in the lower end portion of 6 and is welded to the third tubular body 86 at a position 95. At the upper end of the hole 96, a cylindrical projection 97 is projected in the axial direction. Further, the lower end surface of the third tubular body 86 is chamfered with a width of about 0.5 mm, and the taper portion 85 by this makes it easier to insert the third tubular body 86 into the first tubular body 84. ing. The third tubular body 86 has a smooth outer peripheral surface so that the first tubular body 84 and the third tubular body 86 can slide smoothly, and the upper end edge 92 of the first tubular body 84 is provided. Are fixed to the third tubular body 86 by welding at position 92.

Since the upper edge 92 of the first cylindrical body 84 has an outer shape different from that of the remaining portion, the irradiation position of the YAG laser can be easily determined during welding. Further, since the upper end edge of the first tubular body 84 is formed thin, the heat generated by the emitted laser light is easily transferred to the third tubular body 86. The third tubular body 86 can be reliably welded.

Since the upper end surface 98 of the third cylindrical body 86 and the lower end surface 100 of the receptacle 88 are both finished with high precision and smoothness, the radius is increased while the third cylindrical body 86 and the receptacle 88 are in contact with each other. Can be slid relative to each other. The outer diameter of the lower end surface 100 of the receptacle 88 is formed to be slightly larger than the outer diameter of the upper end surface 98 of the third tubular body 86. In addition, the lower end surface 1 of the receptacle 88
00 in the central part for receiving the projection 97
01 is provided. Position 10 where the upper end surface 98 of the third tubular body 86 and the lower end surface 100 of the receptacle 88 contact
In step 2, welding is performed using a YAG laser, whereby the receptacle 88 is joined to the third cylindrical body 86.

The receptacle 88 has a recessed portion 104 for supporting the ferrule 26 on its outer end surface.
In order to facilitate the insertion of the ferrule 26 into the recessed portion 104, the peripheral edge of the front end surface of the ferrule 26 is chamfered, and due to the tapered portion 106, the ferrule 26 is inserted.
The minimum diameter of 6 is 1.75 mm. Recessed part 10
The shape of the bottom portion of No. 4 is formed according to the shape of the tip portion of the ferrule 26, and the minimum diameter of the recessed portion 104 is about 1.75 mm.

Therefore, when the ferrule 26 is inserted into the recessed portion 104 of the receptacle 88, the tip of the ferrule 26 stops near the bottom of the recessed portion 104, and the ferrule 2 is removed.
6 and the recess 104 are coaxial. Since the ferrule 26 has one end edge of the optical fiber 24 inserted in the central axis portion thereof, the optical fiber 24 and the recessed portion 104 are coaxial with each other.

Even if the accuracy of the diameter of the recessed portion 104 is about 10 μm, the recessed portion 104 and the ferrule 26 are positioned by the taper portion 106, so that a high processing accuracy is required for forming the recessed portion 104. Not done.

The optical semiconductor module 82 having such a structure can be manufactured by the following procedure.

First, the semiconductor light emitting device 4 is attached to the first cylindrical body 84.
Then, the semiconductor light emitting element 4 and the first tubular body 84 are welded at the position 90. Next, the lens 6 is inserted into the second cylinder 94, and then the second cylinder 94 and the third cylinder 86 are welded at the position 95. The ferrule 26 is inserted in the receptacle 88.

The first cylindrical body 84, the third cylindrical body 86, and the receptacle 88 are held at the relative positions shown in FIG. 9, and light is emitted from the optical semiconductor chip 12 of the semiconductor light emitting element 4. Then, while measuring the intensity of the light incident on the optical fiber 24, the sliding adjustment is performed so that the maximum light intensity is obtained. In this sliding adjustment, the first tubular body 84 is slid in the axial direction with respect to the third tubular body 86 for positioning (the allowable width of positional deviation is about 80 μm), and after the positioning, the first tubular body 84 is positioned. The upper end of the is welded to the third tubular body 86 at position 92.

On the other hand, the adjustment of the axis deviation is performed by the abutting surface of the third cylindrical body 86 and the receptacle 88 (the allowable positional deviation width is about 34 μm). After this adjustment, welding with a YAG laser is performed at the edge position 102 of the third tubular body 86, and the upper end surface 98 of the third tubular body 86 is connected to the lower end surface 10 of the receptacle 88.
Fixed at 0. When the YAG laser light is irradiated while inclining to the abutting surface, the bonding strength can be increased. A positional deviation of about ± 5 μm occurs during welding, but any positional deviation falls within an allowable range, so that an optical semiconductor module having high optical coupling efficiency can be manufactured with high yield. Further, it is possible to suppress variations in the total length of the optical semiconductor module 82 to be small.

Further, since the optical axis of the ferrule 26 is aligned with the receptacle 88 by the vicinity of the bottom surface of the former concave portion 104 and the latter taper portion 106, the concave portion 1
04 does not require high processing accuracy. For this reason, the processing becomes easy and the cost can be reduced. Also,
Even if the optical semiconductor chip 12 and the center axis of the lens 6 are slightly deviated from each other, it is possible to optically correct the misalignment between the third cylindrical body 86 and the receptacle 88. Since the outer diameter of the lower end surface 100 of the receptacle 88 is formed to be slightly larger than the outer diameter of the upper end surface 98 of the third cylindrical body 86, even if the correction amount of the axis deviation is increased, A part does not protrude from the outer diameter of the receptacle 88, and the outer diameter W of the optical semiconductor module 82 can always be made to be a constant value.

The third cylindrical body 86 and the receptacle 88 are also provided.
When the and are joined by welding, high temperature dust melted by the YAG laser light is generated at the boundary between the upper end surface 98 of the former and the lower end surface 100 of the latter, and this dust travels in the YAG laser light. The dust is prevented from entering the hole 96 because it is blown away in the direction and adheres to the protrusion 97.

Therefore, the surface of the lens 6 can always be kept clean.

(Embodiment 5) The optical semiconductor module 112 in the embodiment shown in FIG. 10 is partly common to the optical semiconductor module 82 in the embodiment 4, and the common components are designated by the same reference numerals. The optical semiconductor module 112 includes a first cylindrical body 84 in which the semiconductor light emitting element 4 is inserted and fixed, and a second cylindrical body 9 in which the lens 6 is inserted and fixed.
4 and the third cylindrical body 114 having the lower end edge interposed between the first and second cylindrical bodies 84 and 94 form a cylindrical holder, and the receptacle 116 is joined to this. Second cylinder 9
4 is inserted into the lower end portion of the hole 118 of the third tubular body 114, and the tubular protruding portion 120 surrounds the upper end portion of the hole 118.
However, it has an opening 124 in its tip surface 122.

The recess 126 of the receptacle 116 is a straight hole, and the ferrule inserted in this hole is
The tip surface 128 of the ruler 26 is the protrusion 1 of the third tubular body 114.
2 is in contact with the front end surface 122. Receptacle 116
On the lower end surface 130 of the protrusion 12 of the third cylinder 114.
It has a recess 131 for receiving zero. The lower end surface 130 of the receptacle 116 is butted against the upper end surface 132 of the third tubular body 114, and the third tubular body 114 is welded to the receptacle 116 at a position 134 of the edge portion thereof.

Since the recessed portion 126 of the receptacle 116 is a straight hole, it can be processed with higher precision and at a lower cost than a hole having a recess at one end. Therefore, in this example, processing is performed with a tolerance of 3 μm or less. Third cylinder 1
The aperture 124 of 14 allows the light focused by the lens 6 to be input to the optical fiber 24 without loss, so that its diameter is about 1 m.
It is said to be m. Like the lens 6, the hole 118 of the third cylinder 114 has a diameter of about 1.7 mm. Opening 1
The end face 122 having 24 is the end face 12 of the ferrule 26.
The diameter of the opening 124 is formed smaller than that of the front end surface 128 of the ferrule 26 so that the opening 124 can be stably contacted.

The parts of the first cylinder 84, the third cylinder 114, and the receptacle 116 require a certain degree of precision processing. Especially, the hole 126 of the receptacle 116 is 3
A hole diameter tolerance of less than μm is required. Generally, an austenitic stainless steel excellent in machinability and corrosion resistance is used for an optical semiconductor module, but since the austenitic stainless steel contains nickel, sulfur and nickel are melted by melting accompanying welding. May react with each other to form sulfides and crack the weld.

In this embodiment, ferritic stainless steel is used for the first cylinder 84, the third cylinder 114 and the receptacle 116. Since ferritic stainless steel does not contain nickel, nickel sulfide is not generated due to melting accompanying welding and cracks do not occur in the welded part. In particular, the use of ferritic stainless steel containing 0.05% by weight or less of sulfur improves machinability. The higher the sulfur content, the better the machinability, but the more easily sulfides are generated, the sulfur content is preferably 0.05% by weight or less.

In the above-described structure, the distance from the lens 6 to the tip surface of the optical fiber 24 (tip surface 128 of the ferrule 26) is uniquely determined by the outer shape of the third cylindrical body 114. Do not depend. Therefore, the range of variation due to the processing accuracy of the parts is narrowed, the manufacturing yield can be improved, and the adjustment of the optical axis becomes easier.

Further, the lower end surface 130 of the receptacle 116
The dust generated when the upper end surface 132 of the third cylindrical body 114 and the upper end surface 132 of the third cylindrical body 114 are butted and welded to each other does not enter the hole 118 serving as an optical path due to the shielding function of the projection 120,
Dust does not adhere to the surface of the lens 6. Furthermore, since the hole shape of a component that requires precision machining is simplified, the machining is facilitated and the cost of manufacturing the component can be reduced.

A method of manufacturing the optical semiconductor module 112 will be described below with reference to FIGS. First, the semiconductor light emitting element 4 is inserted into the first cylindrical body 84,
The semiconductor light emitting element 4 and the first cylindrical body 84 are welded and fixed at a position 90. Next, the lens 6 is inserted into the second cylindrical body 94, and both are welded and fixed at the position 95. The ferrule 26 is inserted in the receptacle 116 in advance.

FIG. 11A shows an optical semiconductor module 11
2 shows an adjusting device 142 for assembling and adjusting the shaft of FIG. 2, the main part of which is enlarged and shown in FIG. 11 (b).

First cylinder 84 and receptacle 116
Are held by a column 144 and a stage 146 made of metal, respectively. The stage 146 is movable in three directions of X, Y, and Z, and the holder 114 is pressed against the receptacle 116 by a leaf spring 148 so that the holder 114 does not separate from the receptacle 116. The leaf spring 148 is provided with a groove 149 having a width wider than the outer diameter of the holder 114, and the holder 114 has a groove 149.
It can move in the X-axis direction and the Y-axis direction. Leaf spring 14
8 is fixed to the stage 146, the stage 14
The receptacle 116 fixed to 6 can move in the X-axis direction and the Y-axis direction independently of the holder 114. The ferrule 26 inserted into the receptacle 116 is abutted against the holder 114 by the coil spring 150. One end of the coiled spring 150 is fixed by a stopper 152.

When the stage 146 is moved in the Z-axis direction, the outer peripheral edge of the upper end surface of the holder 114 is chamfered to 0.5 mm, so that it can be easily inserted into the first cylindrical body 84. . Since the first tubular body 84 is fixed in the X-axis, Y-axis, and Z-axis directions, the third tubular body 114 inserted in the first tubular body 84 can move only in the Z-axis direction. it can. The third tubular body 114 is pressed by the leaf spring 148 in the Z-axis direction, while the receptacle 116 is pushed by the X-axis.
Since the third cylinder 114 is inserted into the first cylinder 84, the receptacle 116 can be axially adjusted in the X axis direction and the Y axis direction because the third cylinder 114 is inserted into the first cylinder 84. The tip end surface 128 of the ferrule 26 is always in contact with the tip end surface 122 of the third tubular body 114 to adjust the axis. After the axis adjustment is completed, the first cylinder 84 and the third cylinder 114 are connected to the YAG laser.
Then, the third cylinder 114 and the receptacle 116 are adjusted in terms of axial misalignment and then welded.

According to the method described above, the semiconductor light emitting device 4
While the light is emitted to adjust the optical axis, the heat generated from the semiconductor light emitting element 4 is dissipated through the metal support 144. Further, since the ferrule 26 is pressed from below by the spring 150, the position of the light receiving surface of the optical fiber 24 is always kept constant (while being kept in contact with the protrusion 120 of the third cylindrical body 114). Can be assembled. Further, since the third cylindrical body 114 is pressed only in the Z-axis direction by the leaf spring 148, the third cylindrical body 114 and the receptacle 116 do not separate from each other even if the receptacle 116 is moved in the Z-axis direction. , The third tubular body 114 can be moved in the Z-axis direction while being inserted into the first tubular body 84. Therefore, all welded parts can be kept in contact at all times and fixed by welding immediately after the axis adjustment. As a result, the effects of simplifying the assembly and shortening the assembly time can be obtained.

(Embodiment 6) The optical semiconductor module 162 of the embodiment shown in FIG. 12 is partially common to the optical semiconductor module 112 of the embodiment 5, and the common components are designated by the same reference numerals. . This optical semiconductor module 162 differs from the optical semiconductor module 112 of the fifth embodiment in that a ceramic sleeve 166 is provided inside the receptacle 164. Since the ceramic parts can be processed with high precision, the hole 168 of the sleeve 166 is also processed with high precision. The hole 170 for inserting the sleeve 166 does not require as high processing accuracy as the hole 168, and therefore, the receptacle 164 is not required.
High processing accuracy is not required, and the manufacturing cost can be reduced. First tubular body 84 and third tubular body 114
Since high processing accuracy is not required even for the first cylinder 8
4, the third cylinder 114 and the receptacle 164 are formed by applying a sintering method in which metal powder is molded and sintered.
We are trying to reduce the cost of parts. According to this embodiment, although the number of components is increased, the total price of components can be reduced. The material of the sleeve 166 is not limited to ceramics, and may be metal as long as it can be precisely processed.

(Embodiment 7) The optical semiconductor module 182 of the embodiment shown in FIG. 13 is partly common to the optical semiconductor module 112 of the embodiment 5, and the common components are designated by the same reference numerals. . The optical semiconductor module 182 differs from the optical semiconductor module 142 of the fifth embodiment in that the central axis of the receptacle 116 and the central axis (optical axis) of the lens 6 are not coaxial and are inclined by about 5 degrees. In order to tilt the central axis of the ferrule 26 with respect to the central axis of the lens 6 at an angle of about 5 degrees, the hole 1 of the third cylindrical body 184 is
With respect to the plane perpendicular to the central axis of 86, the plane 188 and the plane 19
Both 0 are inclined at an angle of about 5 degrees.

When the center axis of the ferrule 26 coincides with the center axis of the lens, the light reflected by the front end surface 192 of the optical fiber 24 goes backward, is focused by the lens 6 and returns to the optical semiconductor chip 12 side. . When reflected light is incident on the optical semiconductor chip 12, its light emitting state is likely to be unstable. If the ferrule 26 is tilted with respect to the optical axis in order to prevent this, the reflected light travels in a direction different from the optical axis and does not return to the optical semiconductor chip 12 side, so that the light emitting state of the optical semiconductor chip 12 can be stabilized. it can. Such a structure is particularly suitable for an optical semiconductor module for analog signals and can improve distortion characteristics.

In the present embodiment, the inclination angle is set to about 5 degrees, but any angle can be used as long as the return of the reflected light to the semiconductor light emitting element side can be suppressed without impairing the optical coupling to the optical fiber 24. May be. However, if the inclination angle is excessively large, it becomes difficult to allow light to be incident on the optical fiber 24 with high optical coupling efficiency, so 3 to 6 degrees is preferable.

(Embodiment 8) The optical semiconductor module 202 in the embodiment shown in FIG. 14 has a semiconductor light emitting element 204, a cylindrical holder 206, and a receptacle 208. The semiconductor light emitting element 204 has an optical semiconductor chip 12, a protective cap 14, and a stem 16, and the optical semiconductor chip 12 is fixed on a disc-shaped stem 16 via a mount 18. A protective cap 14 that covers the optical semiconductor chip 12 is also fixed to the stem 16.

The light emitted from the optical semiconductor chip 12 is
It is taken out through the light guide 210 provided on the protective cap 14. The stem 16 and the mount 18 are made of an iron-based metal and have a gold plating layer on the surface. Terminal pins 22 are connected to the optical semiconductor chip 12.

The light guide body 210 is made of a glass disk having a diameter of 2 mm and a length of 1 mm provided with a metal plating layer as a total reflection film on the outer peripheral surface, and has antireflection films on both mirror-finished end surfaces. . The outer end face of the light guide 210 is the optical semiconductor chip 1
It occupies a position close to 2 at a distance of 0.5 mm. Rod-shaped lens 21 fixed in the cylindrical holder 206
The outer peripheral surface of 2 is covered with a metal plating film as a total reflection film. The cylindrical holder 206 is welded to the protective cap 14 of the semiconductor light emitting element 204 at the position 214. The receptacle 208 has a recess 216 that supports the ferrule 26, but is abutted against the tubular holder 206 and welded at a position 218.

Most of the light emitted from the optical semiconductor chip 12 enters the light guide 210. The light guide 210 is in contact with the lens 212, and light having a large divergence angle among the incident light is reflected by the metal plating films provided on the outer peripheral surfaces of the light guide 210 and the lens 212.
The light emitted from No. 2 efficiently enters the optical fiber 24 through the lens 212.

Since the light guide 210 is provided at a distance of 0.5 mm from the optical semiconductor chip 12, the lens 21
The light focused by 2 is focused at a position 1 mm from the outer end surface of the lens 212. The front end surface of the ferrule 26 inserted into the receptacle 208 is 1 m from the outer end surface of the lens 212.
Since it stops at the position of m, the distance between the rod type lens 212 and the tip of the optical fiber 24 is mechanically determined by the receptacle 208. Therefore, the cylindrical holder 206 is slid in the radial direction with respect to the receptacle 208 to adjust the axis deviation.

With such a construction, it is sufficient to use only two housing components, and since the adjustment only requires the sliding adjustment in the radial direction, the adjustment work can be facilitated.

Although the laser diode is used for the optical semiconductor chip in the above-described embodiments, a light emitting diode or the like may be used. Further, the lens for condensing the light emitted from the optical semiconductor chip on the tip surface of the optical fiber is not limited to the aspherical one, and may have a condensing characteristic such as a ball lens. Further, instead of joining the first tubular body, the third tubular body, and the receptacle by welding, a joining method other than welding, such as joining with an adhesive, may be applied depending on the application.

The ferritic stainless steel containing 0.05% by weight or less of sulfur used in Example 5 is not peculiar to Example 5, so the first and third cylinders in the other examples are not used. It can also be used for receptacles and the like. Further, the ceramic sleeve used in the sixth embodiment can be similarly applied to the other embodiments. Furthermore, also in the optical semiconductor modules other than the seventh embodiment, the optical axis of the lens and the optical axis of the optical fiber can be relatively inclined.

[0070]

As described above, according to the present invention, it is possible to reduce the number of components and to reduce the cost while maintaining high optical coupling efficiency in the optical system from the optical semiconductor element to the light receiving surface of the optical fiber through the lens. It can be reduced. Further, it is possible to reduce variations in the axial length of the optical semiconductor module.

[Brief description of drawings]

FIG. 1 is a side sectional view of an optical semiconductor module according to an embodiment of the present invention.

FIG. 2 is an explanatory view schematically showing an optical path of an optical semiconductor module.

FIG. 3 is a characteristic diagram of optical coupling efficiency with respect to a distance between a lens and an optical fiber.

FIG. 4 is a characteristic diagram of optical coupling efficiency with respect to a gap between an optical semiconductor chip and a lens.

FIG. 5 is a characteristic diagram of optical coupling efficiency with respect to the amount of axis deviation of an optical fiber.

FIG. 6 is a characteristic diagram of optical coupling efficiency with respect to an amount of misalignment of an optical semiconductor chip.

FIG. 7 is a side sectional view of an optical semiconductor module according to another embodiment of the present invention.

FIG. 8 is a side sectional view of an optical semiconductor module according to another embodiment of the present invention.

FIG. 9 is a side sectional view of an optical semiconductor module according to another embodiment of the present invention.

FIG. 10 is a side sectional view of an optical semiconductor module according to another embodiment of the present invention.

FIG. 11 is a side sectional view of an optical semiconductor module assembling apparatus and a perspective view of a main part of the apparatus.

FIG. 12 is a side sectional view of an optical semiconductor module according to another embodiment of the present invention.

FIG. 13 is a side sectional view of an optical semiconductor module according to another embodiment of the present invention.

FIG. 14 is a side sectional view of an optical semiconductor module according to another embodiment of the present invention.

[Explanation of symbols]

 4 Semiconductor Light Emitting Element 6 Lens 8 Cylindrical Holder 10 Receptacle 24 Optical Fiber 26 Ferrule

Claims (12)

[Claims] 1. A semiconductor light emitting device, a lens for converging light emitted from the semiconductor light emitting device, and the semiconductor light emitting device and the lens for maintaining a predetermined distance between the two members. And a receptacle having a recessed portion on the outer end surface for supporting a ferrule fixed by inserting one end edge of the optical fiber, and an inner end surface of the receptacle is the tubular holder. An optical semiconductor module, which is coaxially butted and fixed to the end surface of the holder on the lens side. 2. A cylindrical holder has a first cylindrical body inserted and fixed with a semiconductor light emitting element, a second cylindrical body inserted with a lens and fixed, and between the first and second cylindrical bodies. A third cylindrical body having a protrusion protruding in the axial direction at the other end by interposing one end edge, and the inner end surface of the receptacle has a recess for receiving the protrusion. Claim 1
The optical semiconductor module described. 3. The optical semiconductor module according to claim 1, wherein a cylindrical portion integrally formed with the lens on the peripheral edge of the lens is in contact with the semiconductor light emitting element. 4. The optical semiconductor module according to claim 1, wherein the outer peripheral surface of the receptacle has a wedge-shaped constricted portion near the inner end surface. 5. The optical semiconductor module according to claim 1, wherein at least one of the cylindrical holder and the receptacle is made of ferritic stainless steel containing 0.05% by weight or less of sulfur. 6. The optical semiconductor module according to claim 1, wherein at least the inner surface of the receptacle is made of ceramics. 7. The optical axis of the light focused by the lens is
The optical semiconductor module according to claim 1, wherein the optical semiconductor module intersects with a central axis of the receptacle. 8. The optical semiconductor module according to claim 2, wherein the protruding portion of the third cylindrical body of the cylindrical holder is in contact with the bottom surface of the concave portion of the receptacle. 9. A semiconductor light emitting element having a built-in optical semiconductor chip and a light guide provided on the light emitting surface side thereof, a lens for focusing light emitted from the semiconductor light emitting element, and the lens inserted therethrough. And a receptacle having a concave portion on the outer end surface for supporting the ferrule fixed by inserting one end edge of the optical fiber, the inner end surface of the receptacle being one end surface of the cylindrical holder. An optical semiconductor module, which is coaxially butted to and fixed to. 10. The light guide body includes a disc, and the two main surfaces of the disc are covered with an antireflection film and the side peripheral surfaces thereof are covered with a reflection film. Optical semiconductor module. 11. A step of fixing a light focusing lens in a cylindrical holder, a step of inserting a semiconductor light emitting element in the cylindrical holder, and a ferrule fixed by inserting one end edge of an optical fiber into a receptacle. Inserting into the recessed portion of the outer end surface, coaxially butting the inner end surface of the receptacle onto one end surface of the cylindrical holder, and the light emitted from the semiconductor light emitting element is caused by the lens to the optical fiber. Fixing the semiconductor light emitting element in the cylindrical holder by adjusting the distance from the semiconductor light emitting element to the lens so that the light is condensed on the light receiving surface of the cylindrical holder and the receptacle. And optically fixing the receptacle to the holder. 12. A semiconductor light emitting element is brought into contact with a cylindrical portion integrally formed with the lens at the periphery of the lens, and a distance from the semiconductor light emitting element to the lens is set to a predetermined value. 11. The method for manufacturing an optical semiconductor module according to item 11.