JPH06308358A - Semiconductor laser module - Google Patents

Abstract

PURPOSE:To suppress the increase of optical coupling loss at the time of mounting it on a base and the increase in the optical coupling loss caused by the change of an ambient temperature in a semiconductor laser module constituted so that a semiconductor laser array is sealed in the package and an optical fiber array attached to the outside of a package and the semiconductor laser array are optically coupled with each other. CONSTITUTION:In the semiconductor laser module, an LD assembly is constituted by mounting the semiconductor laser array 1 and a lens array 2 on a metal block 50, and the LD assembly is housed and sealed in the package 10 having a window 15 on a side wall 11, and the optical fiber array 20 attached to the outside of the side wall 11 and the LD assembly are optically coupled with each other. Then, the metal block 50 is laser welded on the inside surface of the side wall 11 of the package 10.

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 a semiconductor laser array is sealed in a package and an optical fiber array attached to the outside of the package is optically coupled to the semiconductor laser array.

[0002]

2. Description of the Related Art FIG. 6 is a side sectional view of a conventional example, FIG. 7 is a sectional view of essential points of a conventional example, and FIG. 8 is a sectional view of essential points of another conventional example.

In FIGS. 6 and 7, 1 is a semiconductor laser array in which a desired number of semiconductor lasers are arranged in a horizontal row, and 2 is a lens array in which lens portions are arranged in a horizontal row in correspondence with the respective semiconductor lasers.

As shown in detail in FIG. 5, the lens array 2 includes a window frame type lens holder 3 made of a metal material (for example, stainless steel, iron / nickel / cobalt alloy, etc.) using low melting glass. It is glued to be embedded.

Reference numeral 5 is a substantially rectangular parallelepiped metal block made of, for example, iron-nickel-cobalt alloy (trade name: Kovar). The semiconductor laser array 1 is mounted on the upper plane of the metal block 5, and the lens array 2 is mounted on the side surface notch of the metal block 5 in the vicinity of the emitting surface of the semiconductor laser array 1.

A circuit board 4 of aluminum nitride or the like having a pattern equal to the number of semiconductor lasers formed on the surface thereof is mounted on the metal block 5 on the side opposite to the lens array 2.
Each electrode of the semiconductor laser array 1 and the corresponding pattern on the circuit board 4 are connected by wire bonding with a gold wire or the like.

As described above, the LD assembly is constructed by mounting the semiconductor laser array 1, the lens array 2 and the circuit board 4 on the metal block 5. 10 is copper
It is a box-shaped package made of tungsten alloy or the like with an open top. A rectangular window hole is provided in the selected side wall 11 of the package 10, and sapphire or the like is embedded and sealed in the window hole to form the window 15.

Reference numeral 20 denotes a ferrule having a desired number of optical fibers 22.
21 is an optical fiber array arranged in a horizontal row at a pitch equal to the arrangement pitch of the lens portions of the lens array 2,
The incident end face side of the ferrule 21 is inserted and fixed to the sleeve 25.

As the lens array 2 faces the window 15,
The LD assembly is housed in the package 10, and the bottom surface of the metal block 5 is fixed to the bottom plate 12 by soldering (solder 7). Generally, as a fixing means for a small object such as a metal block, laser welding has higher reliability of fixing and shorter fixing time than soldering.

However, since the side wall of the package interferes with laser irradiation, the outer peripheral edge of the bottom surface of the metal block cannot be laser-welded to the bottom plate. Therefore, in the conventional case, the metal block 5 is unavoidably soldered to the bottom plate 12 as described above.

Also, the rear of the LD assembly, that is, the circuit board 4
The drive circuit board 6 is mounted on the bottom plate 12 on the side. Then, the desired lead pattern of the drive circuit board 6 and the circuit board 4 are formed.
The corresponding patterns are connected to each other by wire bonding with a gold wire so that each semiconductor laser emits an optical signal.

An input terminal (not shown) is provided to hermetically penetrate the side wall 11 or the bottom plate 12, and the input terminal and the input pattern of the drive circuit board 6 are connected to each other. A lid is adhered to the opening of the package 10 to seal the LD assembly, the drive circuit board 6 and the like.

The end surface of the sleeve 25 is a window on the outer surface of the side wall 11.
After contacting the position corresponding to 15 and finely moving the sleeve 25 to perform the optical coupling adjustment work between the semiconductor laser and the optical fiber, the sleeve 25 is laser-welded and fixed to the side wall 11.

Then, the bolt 13 is inserted into the fin portion provided on the outside of the package 10 and screwed into the screw hole of the base 9 so that the back surface of the bottom plate 12 of the package 10 is brought into close contact with the upper surface of the base 9. , The package 10 is fixed to the base 9.

In the package 10A shown in FIG. 8, the material of the frame-shaped side wall 11A is made of iron / nickel / cobalt which is approximately equal to the thermal expansion coefficient of sapphire so that the airtightness of the window 15 in which the sapphire is embedded is not deteriorated by heat. As an alloy, the side wall 11
The A and the bottom plate 12 were fixed to each other with a filter (a filter material 8).

[0016]

However, when the upper surface of the base is not flat, if the package in which the side wall and the bottom plate are integrally machined or die-cast is mounted by screwing on the base, As shown in FIG. 7, as a result of the bottom plate of the package being in close contact with the upper surface of the base, the bottom plate is deformed, the optical axis of the semiconductor laser array and the optical axis of the optical fiber array do not match, and the coupling loss increases. There was a point.

On the other hand, in the package in which the side wall made of another metal material is attached to the bottom plate, when the ambient temperature changes due to the difference in thermal expansion coefficient between the bottom plate and the side wall, the side wall as shown in FIG. However, there is a problem that the optical axis of the semiconductor laser array and the optical axis of the optical fiber array do not coincide with each other and the coupling loss increases.

Also, since the package has side walls, it is difficult to laser weld the metal block to the bottom plate. Therefore, conventionally, a metal block is soldered to the surface of the bottom plate as shown in FIGS. As a result, when the temperature of the LD assembly rises near the melting point of the solder, the solder softens, the metal block moves, and the coupling loss increases.

The present invention has been made in view of the above point, and a semiconductor laser module in which an increase in optical coupling loss when mounted on a base and an increase in optical coupling loss due to a change in ambient temperature are suppressed. Is intended to provide.

[0020]

In order to achieve the above object, the present invention mounts a semiconductor laser array 1 and a lens array 2 on a metal block 50 as shown in FIG.
The D assembly is constructed, and the LD assembly is provided with the window 15 on the side wall 11.
In a semiconductor laser module in which an LD assembly is optically coupled with an optical fiber array 20 that is housed and sealed in a package 10 having a package 10 and is attached to the outside of a side wall 11, a metal block 50 is provided on the inner surface of the side wall 11 of the package 10. Are laser welded.

Alternatively, as illustrated in FIG. 3, the semiconductor laser array 1 and the lens array 2 are mounted on a metal block 50 to form an LD assembly, and the LD assembly is housed in a package 10A having a window 15 in a side wall portion. In the semiconductor laser module in which the optical fiber array 20 attached to the outside of the side wall and the LD assembly are optically coupled, the plate member is formed so as to hermetically penetrate the hole of the side wall 11A of the package 10A.
30 is laser-welded, the window 15 is provided in the plate member 30, the metal block 50 is laser-welded to the inner surface of the plate member 30,
The optical fiber array 20 is laser-welded to the outer surface of the plate member 30.

Alternatively, as illustrated in FIG. 4, the metal block 50A has a convex shape in a front view having a U groove in the central projection, and the semiconductor laser array 1 and the lens array 2 are mounted on the bottom portion of the U groove. The upper side of the metal block 50A is the side wall
The plate member (30) attached to the inner side surface or the side wall (11) is laser-welded.

[0023]

According to the present invention as set forth in claim 1, both the LD assembly and the optical fiber array are laser-welded so as to face both inside and outside of the same side wall, and according to the present invention as set forth in claim 2. Both the LD assembly and the optical fiber array are laser-welded so as to face both inner and outer surfaces of the plate member attached to the side wall.

Therefore, even if the surface of the base on which the package is mounted is distorted and the base plate of the package is deformed by mounting the package on the base, the optical coupling loss hardly increases.

Further, even if the ambient temperature changes, the optical coupling loss hardly increases. Furthermore, since the metal block is laser-welded to the side wall or the plate member attached to the side wall, the reliability of the bonding may be lower than that of the solder-bonded one even if the temperature of the LD assembly rises. Absent.

On the other hand, the metal block inserted in the package must be laser-welded by irradiating the laser from directly above since the left and right side walls of the package obstruct the laser irradiation. Therefore, in the rectangular parallelepiped metal block, only the straight upper side portion can be laser-welded, so that the lower portion of the metal block may not adhere to the side wall.

However, according to the third aspect of the present invention, in which the metal block has a convex shape when viewed from the front, the upper side portion of the central projection and the upper side portion of the intermediate step portion of the metal block are irradiated with a laser from directly above. Since the laser welding can be performed, the lower part of the metal block also surely adheres to the side wall (or plate member).

Further, the convex metal block in front view has a larger surface area in contact with the side wall (or plate member) than that of the rectangular parallelepiped shape, so that the cooling property of the semiconductor laser array is improved.

[0029]

The present invention will be described in detail with reference to the drawings. The same reference numerals denote the same objects throughout the drawings.

FIG. 1 is a sectional side view of an embodiment of the present invention, FIG. 2 is a sectional plan view of an embodiment of the present invention, FIG. 3 is a sectional side view of another embodiment of the present invention, and FIG. 4 is a sectional view of the present invention. FIG. 5 is a perspective view of a lens array according to still another embodiment.

In the figure, 1 is a semiconductor laser array in which a desired number of semiconductor lasers are arranged in a horizontal row, and 2 is a lens array in which lens portions are arranged in a horizontal row in correspondence with the respective semiconductor lasers.

As shown in detail in FIG. 5, the lens array 2 is embedded in a window frame type lens holder 3 made of a metal material (for example, stainless steel, iron / nickel / cobalt alloy, etc.) using low melting point glass. It is glued as shown.

Reference numeral 50 is a substantially rectangular parallelepiped metal block made of, for example, iron-nickel-cobalt alloy (trade name: Kovar). The semiconductor laser array 1 is mounted on the upper plane of the metal block 50, the lens array 2 is aligned with the side cutout portion of the metal block 50 in proximity to the emitting surface of the semiconductor laser array 1, and the lens holder 3 is mounted on the metal block 50. It is mounted on the block 50 by laser welding.

A circuit board 4 of aluminum nitride or the like having a pattern equal to the number of semiconductor lasers formed on the surface thereof is mounted on the metal block 50 opposite to the lens array 2.
The LD assembly is configured by connecting the respective electrodes of the semiconductor laser array 1 and the corresponding patterns of the circuit board 4 by wire bonding with a gold wire or the like.

A rectangular window hole is provided in a selected side wall 11 of a box-shaped package 10 made of copper / tungsten alloy or the like having an upper opening, and a window 15 is formed by embedding and sealing sapphire or the like in the window hole. .

On the other hand, a desired number of optical fibers 22 are ferruled.
In the optical fiber array 20, which is arranged in a horizontal row at a pitch equal to the arrangement pitch of the lens portions of the lens array 2, the entrance end face side of the ferrule 21 is inserted and fixed to the sleeve 25.

As shown in FIGS. 1 and 2, the LD assembly is housed in the package 10 so that the lens array 2 faces the window 15, and the upper side portion of the metal block 50 is laser-welded and fixed to the side wall 11. is doing.

Also, behind the LD assembly, that is, the circuit board 4
The drive circuit board 6 is mounted on the bottom plate 12 on the side. Then, the desired lead pattern of the drive circuit board 6 and the circuit board 4 are formed.
The corresponding patterns are connected to each other by wire bonding with a gold wire so that each semiconductor laser emits an optical signal.

A lid is adhered to the opening of the package 10 to seal the LD assembly, the drive circuit board 6 and the like. On the other hand, the end surface of the sleeve 25 is brought into contact with a position corresponding to the window 15 on the outer surface of the side wall 11, and the sleeve 25 is finely moved to perform the optical coupling adjustment work between the semiconductor laser and the optical fiber.
The sleeve 25 is laser-welded and fixed to the side wall 11.

Then, the bolt 13 is inserted into the fin portion (final portion is shown in FIG. 4) provided on the outside of the package 10 and is screwed into the screw hole of the base 9, so that the back surface of the bottom plate 12 of the package 10 is fixed. The package 10 is fixed to the base 9 so as to be in close contact with the upper surface of the base 9.

According to the present invention, since the LD assembly and the optical fiber array 20 are both laser-welded to the inside and outside of the same side wall 11 so as to face each other, the bottom plate 12 is closely attached to the base 9 having a strain on the surface. When the package 10 is mounted, the bottom plate 12 of the package 10 is deformed, but the optical coupling loss between the semiconductor laser array 1 and the optical fiber array 20 hardly increases.

Further, even if the ambient temperature changes, the optical coupling loss hardly increases. On the other hand, the metal block 50 is a side wall
Since it is laser-welded to 11, the reliability of the bonding is not likely to deteriorate even if the temperature of the LD assembly rises, as compared with the conventional one in which the bottom surface of the metal block is soldered and bonded to the bottom plate 12 of the package 10. Have an effect.

In FIG. 3, in the package 10A, the material of the frame-shaped side wall 11A is made of iron / nickel / cobalt which is approximately equal to the thermal expansion coefficient of sapphire so that the airtightness of the window 15 in which the sapphire is embedded is not deteriorated by heat. It is an alloy (trade name: Kovar).

Reference numeral 30 denotes a plate member made of an iron-nickel-cobalt alloy that is inserted into and penetrates a square hole provided in the side wall 11A of the package 10A. A square window hole is provided in the center of the plate member 30, and sapphire or the like is embedded in the window hole and sealed to form the window 15.

Then, the metal block 50 is laser-welded and fixed at a position facing the window 15 on the inner surface of the plate member 30, and the end surface of the sleeve 25 having the optical fiber array 20 inserted therein is attached to the outer surface of the plate member 30. The sleeve 25 is brought into contact and finely moved to perform the optical coupling adjustment work between the semiconductor laser and the optical fiber, and then the sleeve 25 is laser-welded and fixed to the plate member 30.

Finally, the plate member 30 is inserted into the square hole of the side wall 11A, and the flange portion of the plate member 30 is laser-welded to the side wall 11A. As described above, the semiconductor laser module fixed to the package 10A via the plate member 30 has the LD
Since the positioning of the optical fiber array 20 and the semiconductor laser array 1 can be performed outside the package before mounting the assembly, there is an advantage that the adjustment work is easy.

The metal block 50A shown in FIG. 4 has a convex shape when viewed from the front.
A semiconductor laser array 1 and a lens array 2 are provided at the bottom of the groove.
Is equipped with.

Then, by laser welding the upper side portion of the metal block 50A, that is, the upper side portion of the central projection and the upper side portion of the intermediate step portion of the metal block to the inner surface of the side wall 11,
The LD assembly is fixed to the package 10.

Therefore, not only the upper portion of the metal block 50A but also the lower portion of the metal block 50A is surely brought into close contact with the side wall 11. Also, this convex metal block 50A in front view
Since the surface area in contact with the side wall 11 is larger than that of the rectangular parallelepiped shape, the cooling property of the semiconductor laser array is improved.

If a pair of positioning jigs 60 in the shape of a rectangular parallelepiped shown by the dotted lines in the figure support laser welding with both ends of the bottom surface of the metal block 50A supported, the metal block 50A
The laser welding work is facilitated without tilting.

[0051]

As described above, according to the present invention, both the LD assembly and the optical fiber array are laser-welded to the same side wall portion, and even if the surface of the base on which the package is mounted is distorted or the surroundings are present. It has an excellent effect that the optical coupling loss hardly increases even if the temperature changes.

The convex shape of the metal block in the front view
This has the effects of increasing the reliability of fixation of the LD assembly and improving the cooling performance of the semiconductor laser array.

[Brief description of drawings]

FIG. 1 is a side sectional view of an embodiment of the present invention.

FIG. 2 is a plan sectional view of an embodiment of the present invention.

FIG. 3 is a side sectional view of another embodiment of the present invention.

FIG. 4 is a perspective view of a main part of still another embodiment of the present invention.

FIG. 5 is a perspective view of a lens array.

FIG. 6 is a side sectional view of a conventional example.

FIG. 7 is a sectional view of a key part of a conventional example.

FIG. 8 is a cross-sectional view of a key part of another conventional example.

[Explanation of symbols]

1 Semiconductor laser array 2 Lens array 3 Lens holder 4 Circuit board 5,50,50A Metal block 6 Drive circuit board 10,10A Package 11,11A
Side wall 12 Bottom plate 15 Window 20 Optical fiber array 21 Ferrule 22 Optical fiber 25 Sleeve 30 Plate member 50, 50A
Metal block

Front page continued (72) Inventor Tetsuo Watanabe 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Sadayuki Miyata 1015, Kamedotachu, Nakahara-ku, Kawasaki City, Kanagawa Prefecture (72) Invention Person Yoshimitsu Sakai 2-1-1, Kitaichijo-nishi, Chuo-ku, Sapporo-shi, Hokkaido Fujitsu Hokkaido Digital Technology Co., Ltd.

Claims (3)

[Claims] 1. A semiconductor laser array (1) and a lens array
(2) and (2) are mounted on a metal block (50) to form an LD assembly, and the LD assembly is housed and sealed in a package (10) having a window (15) in a side wall (11), and the side wall (11). In a semiconductor laser module in which an optical fiber array (20) attached to the outside of the package and the LD assembly are optically coupled, the metal block (50) is provided on the inner surface of the side wall (11) of the package (10). A semiconductor laser module characterized by being laser-welded. 2. A semiconductor laser array (1) and a lens array
(2) and (2) are mounted on a metal block (50) to form an LD assembly, and the LD assembly is housed and sealed in a package (10A) having a window (15) in a side wall portion and attached to the outside of the side wall. In a semiconductor laser module in which the optical fiber array (20) and the LD assembly are optically coupled, the plate member (30) is laser-welded so as to hermetically penetrate the hole of the side wall (11A) of the package (10). , The window (1
5) is provided, the metal block (50) is laser-welded to the inner surface of the plate member (30), and the optical fiber array is provided on the outer surface of the plate member (30).
(20) A laser diode welded semiconductor laser module. 3. The metal block (50A) has a convex shape in a front view having a U-shaped groove in the center, and the semiconductor laser array 1 and the lens array 2 are mounted on the bottom of the U-shaped groove. The upper side portion of the (50A) is laser-welded to the inner side surface of the side wall (11) or the inner side surface of the plate member (30) attached to the side wall (11). Semiconductor laser module.