JP2001244539A - Semiconductor laser device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor laser device by which the amount of light received by a photodetector can be increased without increasing the size of the photodetector and which is not in danger of being destroyed at the time of wire bonding. SOLUTION: A pattern of traces is formed on the surface of a sub-mount 50 comprised of a laminate of semiconductor layers and a semiconductor laser device 20 is die-bonded on the pattern of traces. The sub-mount 50 is die-bonded on a light-receiving device 30 for record signal detection comprised of a laminate of semiconductor layers for ensuring a direct continuity. The bonding surface of the semiconductor layers in the sub-mount 50 is parallel to the bonding surface of the semiconductor layers in the semiconductor laser device 20 and is perpendicular to the bonding surface of the semiconductor layers in the photodetector 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device used for reading information from an information recording medium such as an optical disk medium, and more particularly, to a semiconductor laser device as a light source which records data via a submount. The present invention relates to a semiconductor laser device mounted on a light receiving element for signal detection.

[0002]

2. Description of the Related Art A hologram laser device shown in FIG. 18 is known as a semiconductor laser device mounted on an optical pickup for reading information from an optical disk medium. In this semiconductor laser device, a semiconductor laser element 20, a light receiving element 30, and a monitoring photodiode 40 are mounted on a stem 10, respectively.

As shown in FIG. 19, a stem 10 has a plate-shaped main body 11 and a block formed by projecting the center of the main body 11 into a L-shape by punching-out using a mold. 12 are provided. A plurality of lead pins 60 as external connection terminals are provided on the main body 11 of the stem 10 in a state perpendicular to the main body 11, respectively. Each of the lead pins 60 is attached to the main body 11 with its upper end slightly protruding from the upper surface of the main body 11.
It extends long below.

A semiconductor laser element 20 as a light source has a laser beam oscillating direction on the upper side of one side surface of a planar L-shaped block portion 12 of the stem 10.
Is mounted so as to be perpendicular to the main body 11. The light receiving element 30 used for recording signal detection is mounted on the upper surface of a side different from the side where the semiconductor laser element 20 in the block section 12 is provided. The monitoring photodiode 40 is disposed on the upper surface of the main body 11 of the stem 10 so as to face the semiconductor laser device 20 provided on the side surface of the block portion 12. The monitoring photodiode 40 is used to monitor the amount of laser light emitted from the semiconductor laser device 20, for example,
The PIN-PD is used, and the light emission amount of the semiconductor laser element 20 is controlled based on the light amount of the laser light monitored by the monitoring photodiode 40.

FIG. 20 is a schematic diagram for explaining the operation of the semiconductor laser device. The laser light oscillated from the semiconductor laser element 20 passes through the hologram element 2 arranged between the semiconductor laser element 20 and the optical disk medium 1 and irradiates the optical disk medium 1. And
The laser light reflected by the optical media disk 1 is
Due to the hologram surface 3 of the hologram element 2, 1 in two directions
The first-order diffracted light 5 that is diffracted next is received by the light receiving element 30. The other primary diffraction light 5 is not used for signal detection.

In order to read information from the optical disk medium 1 at high speed, it is effective to increase the amount of light received by the light receiving element 30 for reading. However, when the optical disk medium 1 is writable, such as a CD-ROM, DVD-ROM, etc., the upper limit of the amount of light applied to the optical disk medium 1 is determined so that the written information is not erased. ing. For this reason, it is difficult to increase the amount of laser light of the semiconductor laser element 20 irradiated to the optical disc medium 1. Therefore, in order to increase the amount of light received by the light receiving element 30, it is necessary to efficiently guide the reflected light from the optical disc medium 1 to the light receiving element 30.

In the semiconductor laser device shown in FIG. 18, only one of the first-order diffracted lights diffracted by the hologram element 2 is received by the light receiving element 30, and the light receiving efficiency of the light receiving element 30 is not always limited. Not good.

Instead of such a semiconductor laser device,
Semiconductor laser devices that make effective use of the diffracted light obtained by the hologram element have been developed. FIG. 21 is a schematic configuration diagram showing an example of such a semiconductor laser device. The semiconductor laser device shown in FIG. 21 includes a light receiving element 30 having a pair of light receiving sections 34 and 35 on an upper surface, and a semiconductor laser element 20 provided between the light receiving sections 34 and 35 in the light receiving element 30. ing. The semiconductor laser device 20 is housed in a concave portion 36 provided at the center of the upper surface of the light receiving device 30.

The semiconductor laser device 20 disposed in the concave portion 36 emits the laser beam 6 in parallel with the bottom surface of the concave portion 36, and the inner surface of the concave portion 36 facing the oscillating portion of the laser beam 6 has: The reflecting surface 37 is inclined so as to reflect the laser beam 6 emitted from the semiconductor laser block 20 upward.

[0010] The laser beam reflected by the optical disk medium is directed in one direction in two directions by a hologram element (not shown).
The first order diffracted light is received by the light receiving unit 34 and the other first order diffracted light is received by the light receiving unit 35.

Japanese Patent Application Laid-Open No. 5-164925 discloses a semiconductor laser device shown in FIG.
In this semiconductor laser device, a pair of light receiving units 34 and 35 are provided on the upper surface of the light receiving element 30.
Between 4 and 35, monitor photodiode 40
And a submount 50. Then, the submount 5 on the monitor photodiode 40
The semiconductor laser element 20 is mounted on the upper part of the side surface of the laser diode 0. The laser beam 6 is emitted upward from the semiconductor laser device 20, and the laser beam 6 reflected by the optical disk medium is transmitted to the laser beam 6 by a hologram device (not shown).
The first order diffracted light is received by the light receiving units 34 and 35, respectively.

In the semiconductor laser device shown in FIGS. 21 and 22, the light receiving element 30 is configured to receive a pair of first-order diffracted lights, and the semiconductor laser device 10 shown in FIG.
The amount of light received by the light receiving element 30 is larger than that of.

[0013]

In the semiconductor laser device shown in FIG. 21, one inner surface of the concave portion 36 is formed to reflect the laser beam 6 emitted from the semiconductor laser element 20 in the horizontal direction upward. It is necessary to make the reflection surface 37 inclined. However, in order to form such a reflective surface 37, a precise processing technique is required, and there is a problem that it cannot be easily formed. In addition, there is a problem that economical efficiency is impaired due to such precision processing.

In the semiconductor laser device shown in FIG. 22, since the semiconductor laser element 20 is mounted on the submount 50 provided on the light receiving element 30, there is a problem that the whole becomes large. In addition, since the monitoring photodiode 40 is also provided on the light receiving element 30, there is a problem that the arrangement position of the semiconductor laser element 20 is restricted.

In such a semiconductor laser device, after assembling on a stem, the semiconductor laser device 20, the submount 50 and the light receiving device 30 are connected to a lead pin for an external electrode terminal by a bonding wire such as an Au wire. Need to be connected by. However, when the semiconductor laser element 20 or the like and the lead pin are wire-bonded with an Au wire, particularly when the Au wire is wire-bonded to the semiconductor laser element 20 and the submount 50, the Au is connected to the submount 50 and the light receiving element 30. The stress is applied by the wire, and the submount 50 may be peeled from the light receiving element 30.

The present invention has been made to solve such a problem, and has as its object to increase the amount of light received by a light receiving element and to reduce the cost without increasing the size of the light receiving element. Can be manufactured, and furthermore,
It is an object of the present invention to provide a semiconductor laser device which is free from destruction or the like by wire bonding.

[0017]

A semiconductor laser device according to the present invention is a semiconductor laser device used for reading information from an information recording medium such as an optical disk medium.
A submount having a pattern wiring provided on the surface thereof, a semiconductor laser device mounted on the pattern wiring of the submount, and a semiconductor layer laminate, A light receiving element for detecting a recording signal, which is mounted so that the submount is directly conductive, wherein a bonding surface of the semiconductor layer in the submount is parallel to a bonding surface of the semiconductor layer in the semiconductor laser device. In addition, it is characterized by being perpendicular to the junction surface of the semiconductor layer in the light receiving element.

The submount is provided with a photodiode for monitoring laser light in the semiconductor laser device.

A semiconductor laser device according to the present invention is used for reading information from an information recording medium such as an optical disk medium. The semiconductor laser device is constituted by a laminate of semiconductor layers and has a pattern on its surface. A sub-mount provided with wiring, a semiconductor laser element mounted on the pattern wiring of the sub-mount, and a stacked layer of semiconductor layers, and a recording signal mounted so that the sub-mount is directly conducted. A light receiving element for detection, wherein a bonding surface of the semiconductor layer in the submount is perpendicular to a bonding surface of the semiconductor layer in the semiconductor laser element, and is parallel to a bonding surface of the semiconductor layer in the light receiving element. It is characterized by being.

The submount and the light receiving element are joined at a plurality of locations by a resin paste containing a conductive metal or by a low melting point metal.

The semiconductor laser device and the submount are joined at a plurality of locations by a resin paste containing a conductive metal or by a low melting point metal.

The light receiving element has a pair of light receiving sections provided on both sides of the semiconductor laser element on the surface on which the submount is mounted, and the pattern of the light receiving area in each light receiving section is mutually symmetric. Or it is asymmetric.

[0023]

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

<Embodiment 1> FIG. 1 is a perspective view showing an example of an embodiment of a semiconductor laser device of the present invention. This semiconductor laser device is provided in an optical pickup for reading information from an optical disk medium such as a CD-ROM, a DVD-ROM or the like. As shown in FIG.
0, a light receiving element 30 for detecting a recording signal mounted on
The semiconductor laser device 20 includes a semiconductor laser device 20 mounted on the light receiving device 30 via a submount 50, and a plurality of lead pins 60 extending vertically downward from the stem 10.

As shown in FIG. 2, the stem 10 is formed in an elliptical flat plate shape. A plurality of lead pins 60 as external connection terminals are provided on the periphery of the stem 10 with respect to the stem 10. And are provided in a vertical state. Each of the lead pins 60 has its upper end slightly protruding from the upper surface of the stem 10, and extends long below the stem 10. At the center of the upper surface of the stem 10, a light receiving element 30 formed of a thin rectangular silicon chip is mounted so that its thickness direction is perpendicular to the upper surface of the stem 10.

The light receiving element 30 composed of a silicon chip, which is a laminated body of semiconductor layers, is mounted on the stem 10 so that the laminating direction of the semiconductor layers is perpendicular to the upper surface of the stem 10. The interface of the layers is parallel to the stem 10.

FIG. 3 is a perspective view of the light receiving element 30, and FIG.
It is the side view. As shown in FIG. 3, a pair of light receiving units 34 and 35 are provided on the upper surface of the light receiving device 30 with a central portion of the upper surface interposed therebetween, and the light receiving device 30 located between the light receiving units 34 and 35 is provided. A submount 50 is mounted in the center of the upper surface of the. Submount 50
As shown in FIG. 5, is electrically connected to the upper surface of the light receiving element 30 by the Ag pastes 71 and 72 in a conductive state.

The submount 50 is also formed of a flat silicon chip which is a laminate of semiconductor layers.
The semiconductor layers are arranged such that the lamination direction of the semiconductor layers is parallel to the upper surface of the light receiving element 30. Therefore, submount 5
0, the bonding surface of the semiconductor layer is perpendicular to the upper surface of the light receiving element 30, and the submount 50 and the light receiving element 30
Means that the bonding surfaces of the semiconductor layers are perpendicular to each other. The semiconductor laser device 20 is mounted on the upper center of one surface of the submount 50.

As shown in FIG. 4, the semiconductor laser device 20 has a structure in which the lamination direction of the semiconductor layers is orthogonal to the surface of the submount 50 on one surface of the submount 50. The bonding surface of the semiconductor layer in the laser element 20 is parallel to the bonding surface of the semiconductor layer in the submount 50. The laser beam 6 is emitted from the semiconductor laser device 20 in a vertical direction along the surface of the submount 50.

The laser light 6 emitted from the semiconductor laser element 20 is applied to the optical disk medium via the hologram element, and the laser light reflected on the optical disk medium is diffracted by the hologram element. And
Each first-order diffracted light diffracted by the hologram element is received by each of the light receiving sections 34 and 35 of the light receiving element 30.

FIG. 6 is a schematic plan view of the light receiving element 30. The light receiving sections 34 and 35 provided on the upper surface of the light receiving element 30 respectively detect a focus servo signal, a tracking servo signal, and a recording signal.
It is divided into five light receiving areas 34a to 34e and 35a to 35e. Each of the first-order diffracted lights applied to each of the light receiving units 34 and 35 is converted into three beams by the hologram element, and each of the beams is further divided into two. Irradiated.

Each of the light receiving sections 34 and 35 has two light receiving areas 34a and 34c, 35a and 35c used for detecting a tracking servo signal by irradiating the two beams in a state of being divided into two, respectively, and one beam. The light is divided into a central light receiving area used for recording signal detection by being irradiated in the divided state. The central light receiving region is divided into two to form one light receiving region 34b and 35b, respectively, and the other region is further divided into two to form light receiving regions 34d and 34e and 35
d and 35e are formed respectively.

FIG. 7 is a perspective view showing the details of the submount 50. As shown in FIG. On one surface of the submount 50 on which the semiconductor laser element 20 is mounted, a pair of wiring patterns 54 and 55 are provided along the vertical direction, respectively, and are arranged below the respective wiring patterns 54 and 55. As shown in FIG. 5, the pads 54b and 55b are joined to the wiring patterns provided on the surface of the light receiving element 30 in a conductive state by Ag pastes 71 and 72, respectively.

FIG. 8 is a perspective view showing a state where the semiconductor laser device 20 is mounted on the submount 50. FIG. The semiconductor laser element 20 has a terminal pad 54 disposed above a wiring pattern 54 formed on the front of the submount 50.
a, the semiconductor laser element 20 and the upper terminal pad 55a of the other wiring pattern 55 are wire-bonded by an Au wire 70 as a bonding wire. Bonded.

The submount 50 and the light receiving element 30 are
Not only the g paste but also a bonding with a resin paste containing another conductive metal, a brazing using In, Au, AuSn or the like having a low melting point may be performed.

The semiconductor laser device having such a configuration is assembled as follows. First, the semiconductor laser device 20
Is die-bonded on the terminal pad 54a of the wiring pattern 54 in the submount 50. At this time, the semiconductor laser device 20 is arranged such that the bonding surface of the semiconductor layer is parallel to the bonding surface of the semiconductor layer in the submount 50. Thereafter, the semiconductor laser device 20 and
The pad 55a of the other wiring pattern 55 in the submount 50 is wire-bonded with the Au wire 70.

Next, the submount 50 on which the semiconductor laser device 20 is mounted is arranged on the surface of the light receiving element 30 and
Ag mounts 71 and 72 allow submount 5
0 with the wiring patterns 54 and 55 of the light receiving element 30 and the submount 50
Is die-bonded on the light receiving element 30.

As described above, in a state where the semiconductor laser element 20 is wire-bonded to the submount 50 in advance, the wiring patterns 54 and 55 are bonded to the light receiving element 30 with Ag paste.
Submount 50 wiring patterns 54 and 55
When the semiconductor laser device 20 and the submount 50 are not bonded to each other as in the case where wire bonding is performed to the semiconductor laser device 20 in a state in which the semiconductor laser device 20 is bonded, the semiconductor laser die-bonded to the submount 50 There is no possibility that the element 20 is peeled off.

Thereafter, the light receiving element 30 provided with the semiconductor laser element 20 and the submount 50 is mounted on the plate-shaped stem 10, and the light receiving element 30 and each lead pin 60 are brought into a conductive state by an Au wire or the like. Connected.

The semiconductor laser device assembled in this manner is mounted on an optical pickup, and includes a CD-ROM,
It is used for reading information from an optical disk medium such as a DVD-ROM.

In the semiconductor laser device having such a configuration,
The light receiving sections 34 and 35 of the light receiving element 30 are provided on both sides of the semiconductor laser element 20, and the light receiving elements 34 and 3
5 is configured to receive each of a pair of first-order diffracted lights by the hologram element, so that the amount of light received by the light receiving element 30 increases without increasing the amount of laser light emitted from the semiconductor laser element 20. Will do. Moreover, such a configuration can be easily and economically realized by using the submount 50.

In the present embodiment, as shown in FIG. 9, one light receiving section 35 is
divided into regions 35a to 35e symmetrical to a to 34e,
The tracking servo signal detection and the focus servo signal detection are respectively performed in the areas on both sides of each of the light receiving sections 34 and 35, and the recording signal is detected in the central area. In order to read at high speed, it is only necessary to speed up the detection of the central recording signal, so that either one of the light receiving units 34 and 35 may be simplified.

FIG. 10 shows a case where the central area in one light receiving section 35 is one area 35b which is not particularly divided. In this case, the focus servo signal is not detected, and the alignment of the light spot 7 is facilitated. FIG. 11 shows a case where the light receiving section 35 is only the area 35b for detecting a recording signal. In this case, since the light receiving section 35 is not provided with areas for tracking servo detection and focus servo signal detection, the entire area of the light receiving sections 34 and 35 can be reduced. It can be downsized and manufactured at low cost.

The submount 50 may be provided with a monitoring photodiode for controlling the amount of light emitted from the semiconductor laser device 20. FIG. 12 is a perspective view of a submount 50 used when a monitor photodiode is provided. At the center of the surface of the submount 50 on which the semiconductor laser element 20 is mounted,
A wiring pattern 56 to which a monitor photodiode (not shown) is die-bonded is provided, and a terminal pad 56b is provided at a lower end thereof. The monitoring photodiode is die-bonded onto the wiring pattern 56 at the center of the surface of the submount 50 so as to receive the laser light emitted downward from the semiconductor laser element 20.

As described above, when the monitoring photodiode is provided on the submount 50, the monitoring photodiode is eliminated from the surface of the light receiving element 30, so that the size of the light receiving element 30 can be further reduced. .

<Embodiment 2> FIG. 13 is a perspective view showing another example of the embodiment of the semiconductor laser device of the present invention, and FIG.
Is a side view thereof. In the semiconductor laser device of this embodiment, a flat submount 50 provided on the light receiving element 30 at the center of the surface is die-bonded with an Ag paste 75 along the surface of the light receiving element 30.
Therefore, the bonding surface of the semiconductor layer in the submount 50 is parallel to the bonding surface of the semiconductor layer in the light receiving element 30.

The submount 50 die-bonded on the light receiving element 30 is connected to the light receiving element 3 by an Au wire 70.
0 is wire-bonded to the wiring pattern on the surface. The semiconductor laser element 20 is die-bonded to the center of the surface of the submount 50. The semiconductor laser element 20 is arranged so that the bonding surface of the semiconductor layer is perpendicular to the submount 50 so that the laser light is emitted upward. The bonding surface of the layers and the bonding surface of the submount 50 are perpendicular to each other.

FIG. 15 is a perspective view of the submount 50. A pair of wiring patterns 57 and 5 are provided on the surface of the submount 50 on which the semiconductor laser element 20 is mounted.
8 are provided. Each wiring pattern 57 and 58
Is so as to be along each electrode portion of the semiconductor laser element 20.
It is provided along each side of the surface of the submount 50, and as shown in FIGS. 16 and 17, each electrode portion of the semiconductor laser device 20 and each of the wiring patterns 57 and 58.
Are connected in a conductive state by Ag pastes 76 and 77. The semiconductor laser device 20 includes a pair of A
g mounts 76 and 77 allow submount 50
Die bonded on top.

In the semiconductor laser device having such a configuration,
After the semiconductor laser device 20 is die-bonded to the submount 50, the submount 50 to which the semiconductor laser device 20 is die-bonded is die-bonded to the light receiving element 30 to be assembled.

The semiconductor laser device 20 includes a submount 5
Since it is die-bonded to 0, wire bonding with Au wire or the like is not required. Therefore, there is no possibility that stress is applied to the submount 50 and the semiconductor laser element 20 at the time of wire bonding, and the semiconductor laser element 20 die-bonded to the submount 50 is separated from the submount 50.

[0051]

According to the semiconductor laser device of the present invention, since the semiconductor laser element is die-bonded to the submount and thus die-bonded to the light-receiving element,
It is possible to increase the amount of light received by the light receiving element,
In addition, the whole can be reduced in size and can be manufactured at low cost. Further, by providing a monitor photodiode for controlling the light emission amount of the semiconductor laser element on the submount, the size can be further reduced.

Furthermore, the bonding surface of the semiconductor layer of the semiconductor laser device is parallel to the bonding surface of the semiconductor layer of the submount, and the bonding surface of the semiconductor layer of the submount is perpendicular to the bonding surface of the semiconductor layer of the light receiving device. By this, the submount is prevented from being peeled off from the light receiving element in which the respective joining surfaces are perpendicular to each other.

Further, when the bonding surface of the semiconductor laser device is perpendicular to the bonding surface of the submount, and the bonding surface of the submount is parallel to the bonding surface of the light receiving device, the semiconductor laser becomes perpendicular to each other. Since the element and the submount are directly connected to each other, there is no possibility that the semiconductor laser element is peeled off from the submount.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of an embodiment of a semiconductor laser device of the present invention.

FIG. 2 is a perspective view showing a configuration of a stem in the semiconductor laser device.

FIG. 3 is a perspective view showing a configuration of a chip portion mounted on the stem.

FIG. 4 is a side view showing a mounted state of a chip portion mounted on the stem.

FIG. 5 is a perspective view showing a configuration of a chip portion mounted on the stem.

FIG. 6 is a plan view showing a configuration diagram of a chip portion mounted on the stem.

FIG. 7 is a perspective view of a submount mounted on the stem.

FIG. 8 is a perspective view showing a state where a semiconductor laser element is mounted on the submount.

FIG. 9 is a plan view of a light receiving element on which the submount is mounted.

FIG. 10 is a plan view showing another example of the light receiving element.

FIG. 11 is a plan view showing still another example of the light receiving element.

FIG. 12 is a perspective view showing an example of a submount on which a monitor photodiode is mounted.

FIG. 13 is a perspective view showing another example of the embodiment of the semiconductor laser device of the present invention.

FIG. 14 is a side view showing a mounted state of a chip portion mounted on a stem of the semiconductor laser device.

FIG. 15 is a perspective view of a submount used in the semiconductor laser device.

FIG. 16 is a perspective view showing a state where a semiconductor laser element is mounted on the submount.

FIG. 17 is a side view thereof.

FIG. 18 is a perspective view showing an example of a conventional semiconductor laser device.

FIG. 19 is a perspective view showing a stem portion of the semiconductor laser device.

FIG. 20 is a schematic configuration diagram for explaining the operation of a conventional semiconductor laser device.

FIG. 21 is a perspective view showing another example of a conventional semiconductor laser device.

FIG. 22 is a perspective view showing still another example of a conventional semiconductor laser device.

[Explanation of symbols]

 Reference Signs List 10 stem 20 semiconductor laser element 30 light receiving element 34, 35 light receiving section 50 submount 54, 55 wiring pattern 56 monitor photodiode 60 lead pin 70 Au wire 71, 72, 73, 75, 76, 77 Ag paste

Claims (6)

[Claims] 1. A semiconductor laser device used for reading information from an information recording medium such as an optical disk medium, comprising: a submount having a layered structure of semiconductor layers and having a pattern wiring provided on a surface thereof. A semiconductor laser element mounted on the pattern wiring of the submount, and a light receiving element for detecting a recording signal, which is constituted by a stacked body of semiconductor layers and is mounted so that the submount is directly conductive. The bonding surface of the semiconductor layer in the submount is parallel to the bonding surface of the semiconductor layer in the semiconductor laser device, and is perpendicular to the bonding surface of the semiconductor layer in the light receiving device. Semiconductor laser device. 2. The semiconductor laser device according to claim 1, wherein the submount is provided with a photodiode for monitoring laser light in the semiconductor laser element. 3. A semiconductor laser device used for reading information from an information recording medium such as an optical disk medium, comprising: a submount having a layered body of semiconductor layers and having a pattern wiring provided on a surface thereof. A semiconductor laser element mounted on the pattern wiring of the submount, and a light receiving element for detecting a recording signal, which is constituted by a stacked body of semiconductor layers and is mounted so that the submount is directly conductive. A semiconductor laser, wherein a bonding surface of the semiconductor layer in the submount is perpendicular to a bonding surface of the semiconductor layer in the semiconductor laser device and parallel to a bonding surface of the semiconductor layer in the light receiving device. apparatus. 4. The submount and the light receiving element,
By a resin paste containing a conductive metal, or
4. The semiconductor laser device according to claim 1, wherein the semiconductor laser device is joined at a plurality of locations by a low melting point metal. 5. The semiconductor laser device and the submount are formed by a resin paste containing a conductive metal.
4. The semiconductor laser device according to claim 1, wherein the semiconductor laser device is joined at a plurality of locations by a low melting point metal. 6. The light receiving element has a pair of light receiving sections provided on both sides of the semiconductor laser element on a surface on which the submount is mounted, and a pattern of a light receiving area in each light receiving section is different from each other. 4. The semiconductor laser device according to claim 1, which is symmetric or asymmetric.