Patent Publication Number: US-2011051773-A1

Title: Semiconductor laser device

Description:
This application is based on Japanese Patent Application No. 2009-195509 filed on Aug. 26, 2009, the contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a semiconductor laser device and particularly to a semiconductor laser device provided with a plurality of semiconductor laser elements. 
     2. Description of Related Art 
     A semiconductor laser device provided with a plurality of semiconductor laser elements have been known (See Japanese Unexamined Patent Application Publication No. 2005-327905, for example). 
     Japanese Unexamined Patent Application Publication No. 2005-327905 discloses a semiconductor light-emitting device (semiconductor laser device) provided with a light-emitting element with two wavelengths (multi-wavelength semiconductor laser element) used for recording/replaying of CD (Compact Disc) and DVD (Digital Versatile Disc), a light-emitting element (semiconductor laser element) with one wavelength used for recording/replaying of BD (Blu-ray Disc (registered trademark)), and a supporting base (mounting member) on which they are mounted. 
     In this semiconductor light-emitting device, the two-wavelength light-emitting element and the one-wavelength light-emitting element are mounted on the supporting base in a laminated state. Specifically, the two-wavelength light-emitting element is mounted on the one-wavelength light-emitting element such that the light emitting point (light emitting portion) side of the two-wavelength light-emitting element and the light emitting point side of the one-wavelength light-emitting element oppose each other. Then, the rear face side (the side opposite to the light emitting point) of the one-wavelength light-emitting element is mounted on the supporting base. 
     However, according to Japanese Unexamined Patent Application Publication No. 2005-327905, a plurality of processes including deposition of an insulating layer and deposition of an adhesive layer are necessary in order to bond the two-wavelength light-emitting element (multi-wavelength semiconductor laser element) onto the one-wavelength light-emitting element (semiconductor laser element) and has a problem that productivity of the semiconductor light-emitting device (semiconductor laser device) is lowered. 
     In order to improve the productivity of the semiconductor light-emitting device, there can be such a method that the two-wavelength light-emitting element and the one-wavelength light-emitting element are not laminated but each light-emitting element is mounted side by side on the supporting base. In this case, there is a problem that a distance between the light emitting point (particularly the light emitting point arranged on the side opposite to the one-wavelength light-emitting element) of the two-wavelength light-emitting element and the light emitting point of the one-wavelength light-emitting element tends to be large. If the distance between the light emitting points becomes large, it becomes difficult to make an optical member such as a lens to which light emitted from the light emitting point is radiated shared by the two-wavelength light-emitting element and one-wavelength light-emitting element, and the advantage that the two-wavelength light-emitting element and the one-wavelength light-emitting element are mounted on the one semiconductor light-emitting device is weakened. 
     Also, in Japanese Unexamined Patent Application Publication No. 2005-327905, since the two-wavelength light-emitting element is mounted on the one-wavelength light-emitting element, an electrode on which the two-wavelength light-emitting element is mounted needs to be formed on the one-wavelength light-emitting element, and, a wire for external connection needs to be bonded to the electrode. Thus, the electrode needs to be formed to a sufficient size, and the one-wavelength light-emitting element needs to be formed so as to have an area at least larger than that of the two-wavelength light-emitting element. This leads to the problem of the one-wavelength light-emitting element being large. 
     SUMMARY OF THE INVENTION 
     The present invention was made in order to solve the above problems and has an object to provide a semiconductor laser device that can suppress size increase of a semiconductor laser element, suppress widening of an interval between light emitting portions, and improve productivity. 
     In order to achieve the above object, the semiconductor laser device according to one aspect of the present invention includes a first semiconductor laser element, a second semiconductor laser element that is arranged adjacently to the first semiconductor laser element and is a monolithic multi-wavelength semiconductor laser element, and a mounting member on which the first semiconductor laser element and the second semiconductor laser element are junction-down mounted, in which the second semiconductor laser element includes a semiconductor substrate, and, of the side faces of the semiconductor substrate of the second semiconductor laser element, a side face arranged opposite the first semiconductor laser element is inclined with respect to the normal direction of a major face of the semiconductor substrate so that a distance from the first semiconductor laser element is increasingly large away from the mounting member. 
     With the semiconductor laser device according to one aspect, as mentioned above, by junction-down mounting the first semiconductor laser element and the second semiconductor laser element on the mounting member, the distance between the light emitting portion of the first semiconductor laser element and the mounting member can be made smaller and, the distance between the light emitting portion of the second semiconductor laser element and the mounting member can be made smaller. As a result, among relative distances between the light emitting portion of the first semiconductor laser element and the light emitting portion of the second semiconductor laser element, the distance in the thickness direction of the first semiconductor laser element and the second semiconductor laser element can be made smaller. Also, as compared with a case in which the first semiconductor laser element and the second semiconductor laser element are junction-up mounted on the mounting member, an error in height positions of the light emitting portion of the first semiconductor laser element and the light emitting portion of the second semiconductor laser element can be kept extremely small. Also, since heat generated in the light emitting portion of the first semiconductor laser element and the light emitting portion of the second semiconductor laser element can be efficiently transferred to the mounting member, radiation performances of the first semiconductor laser element and the second semiconductor laser element can be improved. 
     Also, with the semiconductor laser device according to one aspect, as mentioned above, by junction-down mounting the first semiconductor laser element and the second semiconductor laser element on the mounting member, unlike a case in which the first semiconductor laser element and the second semiconductor laser element are laminated, a plurality of processes of bonding the first semiconductor laser element and the second semiconductor laser element are not required. As a result, productivity drop of the semiconductor laser device can be suppressed. Also, with the semiconductor laser device according to one aspect, unlike a case in which the first semiconductor laser element and the second semiconductor laser element are laminated, since there is no need to increase the size of one of the semiconductor laser elements (the first semiconductor laser element, for example), the size increase of the semiconductor laser element can be suppressed. 
     Also, with the semiconductor laser device according to one aspect, as mentioned above, of the side faces of the semiconductor substrate of the second semiconductor laser element, the side face arranged opposite the first semiconductor laser element is inclined with respect to the normal direction of the major face of the semiconductor substrate so that the distance from the first semiconductor laser element is increasingly large away from the mounting member. As a result, as compared with a case in which, of the side faces of the second semiconductor laser element, the side face arranged opposite the first semiconductor laser element is inclined with respect to the normal direction of the major face of the semiconductor substrate so that the distance from the first semiconductor laser element is increasingly small away from the mounting member, the light emitting portion of the first semiconductor laser element can be arranged closer to the light emitting portion of the second semiconductor laser element. Thus, the increase in the distance between the light emitting portion of the first semiconductor laser element and the light emitting portion of the second semiconductor laser element can be suppressed. As a result, since an optical member such as a lens to which light emitted from the light emitting portions is radiated can be shared by the first semiconductor laser element and the second semiconductor laser element, an increase in the number of components can be suppressed, and the size increase of the entire device can be suppressed. 
     In the semiconductor laser device according to one aspect, the first semiconductor laser element preferably has a first light emitting portion that emits laser light, and the first light emitting portion is arranged on the second semiconductor laser element side of the center of the first semiconductor laser element. By configuring as above, the first light emitting portion of the first semiconductor laser element can be arranged still closer to the second semiconductor laser element. As a result, the increase in the distance between the first light emitting portion of the first semiconductor laser element and the light emitting portion of the second semiconductor laser element can be further suppressed. 
     In the semiconductor laser device according to one aspect, the second semiconductor laser element preferably has a second light emitting portion and a third light emitting portion that emit laser light having wavelengths different from each other, respectively, and the center between the second light emitting portion and the third light emitting portion is located on the first semiconductor laser element side of the center of the major face of the semiconductor substrate of the second semiconductor laser element. By configuring as above, the second light emitting portion and the third light emitting portion of the second semiconductor laser element can be arranged still closer to the first semiconductor laser element. As a result, the increase in the distance from the second light emitting portion and the third light emitting portion of the second semiconductor laser element to the light emitting portion of the first semiconductor laser element can be further suppressed. 
     In the semiconductor laser device according to one aspect, the first semiconductor laser element preferably has a first light emitting portion that emits laser light, the second semiconductor laser element preferably has a second light emitting portion and a third light emitting portion that emit laser light having wavelengths different from each other, respectively, the second light emitting portion is arranged between the third light emitting portion and the first light emitting portion of the first semiconductor laser element, and the distance between the first light emitting portion of the first semiconductor laser element and the second light emitting portion of the second semiconductor laser element is no more than the distance between the second light emitting portion and the third fight emitting portion of the second semiconductor laser element. By configuring as above, the increase in the distance from the first light emitting portion of the first semiconductor laser element to the second light emitting portion and the third light emitting portion of the second semiconductor laser element can be farther suppressed. 
     In the semiconductor laser device according to one aspect, the semiconductor substrate of the second semiconductor laser element may include an off substrate in which the major face has an off angle, and the side face of the semiconductor substrate of the second semiconductor laser element may be a cleavage face. 
     In the semiconductor laser device according to one aspect, the first semiconductor laser element may include a nitride semiconductor substrate. 
     In the semiconductor laser device according to one aspect, the semiconductor substrate of the second semiconductor laser element may include a GaAs substrate. 
     In the semiconductor laser device according to one aspect, the first semiconductor laser element may include a blue-violet semiconductor laser element. 
     In the semiconductor laser device according to one aspect, the second semiconductor laser element may include an infrared semiconductor laser element portion and a red semiconductor laser element portion. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view illustrating a structure of a three-wavelength semiconductor laser device according to an embodiment of the present invention. 
         FIG. 2  is a diagram for explaining an effect of the three-wavelength semiconductor laser device according to the embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     An embodiment of the present invention will be described below referring to the attached drawings. 
     Referring to  FIG. 1 , a structure of a three-wavelength semiconductor laser device  1  according to the embodiment of the present invention will be described. The three-wavelength semiconductor laser device  1  is an example of a “semiconductor laser device” of the present invention. 
     The three-wavelength semiconductor laser device  1  according to the embodiment of the present invention includes, as shown in  FIG. 1 , a blue-violet semiconductor laser element  10 , a two-wavelength semiconductor laser element  20  and a sub-mount  2  on which a blue-violet semiconductor laser element  10  and a two-wavelength semiconductor laser element  20  are junction-down mounted. The blue-violet semiconductor laser element  10  is an example of a “first semiconductor laser element” of the present invention, and the two-wavelength semiconductor laser element  20  is an example of a “second semiconductor laser element” of the present invention. Also, the sub-mount  2  is an example of a “mounting member” of the present invention. 
     The blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20  are arranged adjacently to each other in a width direction (X-direction). Also, the blue-violet semiconductor laser element  10  is arranged on one side (X 1  direction side) in the X-direction of the two-wavelength semiconductor laser element  20 . 
     The blue violet semiconductor laser element  10  has a function of emitting laser light (blue-violet laser light) in a wavelength band of approximately 405 nm, for example, and is used for recording replaying of BD. 
     Also, the blue-violet semiconductor laser element  10  includes a semiconductor substrate  11  made of GaN having a thickness of approximately 100 μm, a GaN semiconductor layer  12  formed on a major face  11   a  of the semiconductor substrate  11 , and an electrode layer  13  formed on the semiconductor layer  12 . Also, an electrode layer, not shown, may be disposed on the rear face of the semiconductor substrate  11 . The semiconductor substrate  11  is an example of a “nitride semiconductor substrate” of the present invention. 
     The major face  11   a  of the semiconductor substrate  11  is a ( 0001 ) face and has a width (W 1 ) of approximately 100 μm in the width direction (X-direction). 
     Also, an end face  11   b  (face in parallel with the paper surface; XY plane) of the semiconductor substrate  11  (the blue-violet semiconductor laser element  10 ) is formed substantially in a square shape (or substantially in a rectangular shape). This end face  11   b  is a cleavage face formed by cleavage. 
     Also, side faces  11   c  and  11   d  of the semiconductor substrate  11  are formed substantially perpendicularly (Y-direction) to the major face  11   a  of the semiconductor substrate  11 . These side faces  11   c  and  11   d  are formed by dicing. 
     In the semiconductor layer  12 , a light guide path (not shown) extending in a direction (Z-direction) perpendicular to the paper surface is formed. An end portion on one side of this light guide path is a light emitting portion  12   a  that emits laser light. The light emitting portion  12   a  is an example of a “first light emitting portion” of the present invention. 
     Here, in this embodiment, the light emitting portion  12   a  is arranged at a position separated from the side face  11   d  on the two-wavelength semiconductor laser element  20  side (X 2  direction side) of the semiconductor substrate  11  by a distance W 2  of approximately 40 μm. That is, the light emitting portion  12   a  is arranged on the two-wavelength semiconductor laser element  20  side (X 2  direction side) of the center L 1  in the X-direction of the semiconductor substrate  11  (blue-violet semiconductor laser element  10 ). 
     The electrode layer  13  is mounted on a wiring portion  2   a  of the sub-mount  2  via a solder layer  3 . 
     The two-wavelength semiconductor laser element  20  is arranged at a distance W 11  of approximately 30 μm from the blue-violet semiconductor laser element  10 . Also, the two-wavelength semiconductor laser element  20  is a monolithic two-wavelength (multi-wavelength) semiconductor laser element and includes a semiconductor substrate  21  made of GaAs having a thickness of approximately 100 μm, a red semiconductor laser element portion  30  and an infrared semiconductor laser element portion  40  disposed in predetermined regions on a major face  21   a  of the semiconductor substrate  21 . Also, on the rear face of the semiconductor substrate  21 , an electrode layer, not shown, may be disposed. The semiconductor substrate  21  is an example of the “GaAs substrate” of the present invention. 
     The major face  21   a  of the semiconductor substrate  21  has a width (W 21 ) of approximately 200 μm in the width direction (X-direction). Also, the semiconductor substrate  21  is an off substrate, and the major face  21   a  of the semiconductor substrate  21  is a face inclined with an off angle of approximately 13° from a ( 100 ) face to a [ 011 ] direction. The [ 011 ] direction is a direction inclined by approximately  13 ° with respect to the X-direction. 
     Also, in this embodiment, an end face  21   b  (face in parallel with the paper surface; an XY-plane) of the semiconductor substrate  21  (two-wavelength semiconductor laser element  20 ) is formed substantially in a parallelogram. Specifically, side faces  21   c  and  21   d  of the semiconductor substrate  21  are inclined by a predetermined angle α (=approximately 13°) with respect to a normal direction (Y-direction) of the major face  21   a  of the semiconductor substrate  21  so that the distance from the blue-violet semiconductor laser element  10  is increasingly large away from the sub-mount  2 . 
     Also, the end face  21   b  of the semiconductor substrate  21  is a cleavage face formed by cleavage. Also, the side faces  21   c  and  21   d  of the semiconductor substrate  21  are cleavage faces formed by cleavage similar to the end face  21   b.    
     The red semiconductor laser element portion  30  has a function of emitting laser light in a wavelength band of approximately 660 nm (red laser light), for example, and is used for recording/replaying and the like of DVD. The infrared semiconductor laser element portion  40  has a function of emitting laser light of a wavelength of approximately 785 nm band (infrared laser light), for example, and is used for recording/replaying and the like of CD. 
     Also, the red semiconductor laser element portion  30  is formed in an X 1 -direction side portion on the major face  21   a  of the semiconductor substrate  21 , and the infrared semiconductor laser element portion  40  is formed in an X 2 -direction side portion on the major face  21   a  of the semiconductor substrate  21 . Also, the red semiconductor laser element portion  30  and the infrared semiconductor laser element portion  40  are arranged with a predetermined interval between them in the X-direction. 
     Also, the red semiconductor laser element portion  30  is arranged with a predetermined interval from the side face  21   c  of the semiconductor substrate  21 . Also, the infrared semiconductor laser element portion  40  is arranged with a predetermined interval from the side face  21  d of the semiconductor substrate  21 . 
     Also, the red semiconductor laser element portion  30  includes an AlGaInP semiconductor layer  31  and an electrode layer  32  formed on the semiconductor layer  31 . 
     In the semiconductor layer  31 , a light guide path (not shown) extending in a direction (Z-direction) perpendicular to the paper surface is formed. An end portion on one side of this light guide path is a light emitting portion  31   a  that emits laser light. The light emitting portion  31   a  is an example of a “second light emitting portion” of the present invention. 
     The light emitting portion  31   a  is arranged at a position away from the side face  21   c  on the X 1 -direciton side of the semiconductor substrate  21  by approximately 40 μm. Also, the light emitting portion  31   a  is arranged between the light emitting portion  12   a  of the blue-violet semiconductor laser element  10  and a light emitting portion  41   a , which will be described later, of the infrared semiconductor laser element portion  40 . 
     The electrode layer  32  is mounted on a wiring portion  2   b  of the sub-mount  2  via the solder layer  3 . 
     The infrared semiconductor laser element portion  40  includes an AlGaAs semiconductor layer  41  and an electrode layer  42  formed on the semiconductor layer  41 . 
     In the semiconductor layer  41 , a light guide path (not shown) extending in a direction (Z-direction) perpendicular to the paper surface is formed. An end portion on one side of this light guide path is a light emitting portion  41   a  that emits laser light. The light emitting portion  41   a  is an example of a “third light emitting portion” of the present invention. 
     The light emitting portion  41   a  is arranged at a position away from the side face  21   d  on the X 2 -direciton side of the semiconductor substrate  21  by approximately 50 μm. Therefore, in this embodiment, the center P 1  between the light emitting portion  31   a  and the light emitting portion  41   a  is located on the blue-violet semiconductor laser element  10  side (X 1 -direciton side) of the center L 11  in the X-direction of the major face  21   a  of the semiconductor substrate  21 . 
     Also, in this embodiment, a distance W 31  between the light emitting portion  31   a  and the light emitting portion  12   a  of the blue-violet semiconductor laser element  10  is approximately 110 μm, and a distance W 32  between the light emitting portion  31   a  and the light emitting portion  41   a  is also approximately 110 μm. That is, in this embodiment, the distance W 31  between the light emitting portion  31   a  and the light emitting portion  12   a  of the blue-violet semiconductor laser element  10  is the same as the distance W 32  between the light emitting portion  31   a  and the light emitting portion  41   a.    
     The electrode layer  42  is mounted on a wiring portion  2   c  of the sub-mount  2  via the solder layer  3 . 
     The sub-mount  2  has the blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20  electrically connected thereto, and also has a function of radiating heat generated in the blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20 . 
     In this embodiment, as mentioned above, by junction-down mounting the blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20  on the sub-mount  2 , the distance between the light emitting portion  12   a  of the blue-violet semiconductor laser element  10  and the sub-mount  2  can be reduced, and the distance between the light emitting portions  31   a  and  41   a  of the two-wavelength semiconductor laser element  20  and the sub-mount  2  can be reduced. As a result, the distance in the Y-direction (the thickness direction of the blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20 ) between each light emitting portion ( 12   a ,  31   a , and  41   a ) of the blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20  can be minimized, and the distance between each light emitting portion ( 12   a ,  31   a , and  41   a ) can be reduced. Also, as compared with the case in which the blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20  are junction-up mounted on the sub-mount  2 , an error in the height position (position in the Y-direction) of each light emitting portion ( 12   a ,  31   a , and  41   a ) can be kept extremely small. Also, since the heat generated in each light emitting portion ( 12   a ,  31   a , and  41   a ) can be efficiently transferred to the sub-mount  2 , radiation performances of the blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20  can be improved. 
     Also, in this embodiment, as mentioned above, by junction-down mounting the blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20  on the sub-mount  2 , unlike the case in which the blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20  are laminated, a plurality of processes for bonding the blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20  are not required. As a result, productivity drop in the three-wavelength semiconductor laser device  1  can be suppressed. Also, in this embodiment, unlike the case in which the blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20  are laminated, there is no need to increase the size of one of the semiconductor laser elements (the blue-violet semiconductor laser element  10 , for example), and the increase in size of the semiconductor laser element (the blue-violet semiconductor laser element  10 , for example) can be suppressed. 
     Also, in this embodiment, as mentioned above, the side faces  21   c  and  21   d  of the semiconductor substrate  21  of the two-wavelength semiconductor laser element  20  are inclined with respect to the normal direction of the major face  21   a  of the semiconductor substrate  21  so that the distance from the blue-violet semiconductor laser element  10  is increasingly large away from the sub-mount  2 . As a result, the distance between the side face  11   d  and the side face  21   c  on the rear face side of the semiconductor substrates  11  and  21  can be increased, and workability when mounting the blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20  on the sub-mount  2  can be improved. Also, as shown in  FIG. 2 , for example, as compared with the case where side faces  121   c  and  121   d  of a semiconductor substrate  121  of a two-wavelength semiconductor laser element  120  are inclined with respect to the normal direction of a major face  121   a  of the semiconductor substrate  121  so that the distance from a blue-violet semiconductor laser element  110  is made increasingly small away from the sub-mount  2 , the light emitting portion  12   a  of the blue-violet semiconductor laser element  10  can be arranged closer to the light emitting portions  31   a  and  41   a  of the two-wavelength semiconductor laser element  20 . Therefore, increase in the distance between the light emitting portion  12   a  of the blue-violet semiconductor laser element  10  and the light emitting portions  31   a  and  41   a  of the two-wavelength semiconductor laser element  20  can be suppressed. As a result, since an optical member (not shown) such as a lens to which light emitted from the light emitting portions  12   a ,  31   a , and  41   a  is radiated can be shared by the blue-violet semiconductor laser element  10  and the two-wavelength semiconductor laser element  20 , an increase in the number of components can be suppressed, and size increase of the entire device can be suppressed. 
     In the structure shown in  FIG. 2 , since it is necessary to prevent contact between the blue-violet semiconductor laser element  110  and the two-wavelength semiconductor laser element  120 , a distance W 101  between a light emitting portion  112   a  of the blue-violet semiconductor laser element  110  and a light emitting portion  141   a  of a red semiconductor laser element portion  140  of the two-wavelength semiconductor laser element  120  cannot be reduced easily. Therefore, it is difficult to share the optical member (not shown) such as a lens to which light emitted from the light emitting portions  112   a ,  131   a , and  141   a  is radiated. 
     Also, in this embodiment, as mentioned above, by arranging the light emitting portion  12   a  on the two-wavelength semiconductor laser element  20  side of the center L 1  of the blue-violet semiconductor laser element  10 , the light emitting portion  12   a  of the blue-violet semiconductor laser element  10  can be arranged still closer to the two-wavelength semiconductor laser element  20 . As a result, increase in the distance between the light emitting portion  12   a  of the blue-violet semiconductor laser element  10  and the light emitting portions  31   a  and  41   a  of the two-wavelength semiconductor laser element  20  can be further suppressed. 
     Also, in this embodiment, as mentioned above, the center P 1  between the light emitting portion  31   a  and the light emitting portion  41   a  is located on the blue-violet semiconductor laser element  10  side of the center L 11  in the X-direction of the major face  21   a  of the semiconductor substrate  21 . As a result, the light emitting portions  31   a  and  41   a  of the two-wavelength semiconductor laser element  20  can be arranged still closer to the blue-violet semiconductor laser element  10 . As a result, the increase in the distance between the light emitting portions  31   a  and  41   a  of the two-wavelength semiconductor laser element  20  and the light emitting portion  12   a  of the blue-violet semiconductor laser element  10  can be further suppressed. 
     The embodiment disclosed here should be considered as an exemplification in all the points but not limiting. The scope of the present invention is shown not by the above description of the embodiment but by claims and includes all the changes in meanings and scopes equal to the claims. 
     For example, in the above embodiment, the example in which the two-wavelength semiconductor laser element including two semiconductor laser element portions is used was shown as the second semiconductor laser element (multi-wavelength semiconductor laser element), but the present invention is not limited to that and a multi-wavelength semiconductor laser element including three or more semiconductor laser element portions may be used. 
     Also, as the first semiconductor laser element, a multi-wavelength semiconductor laser element may be used. 
     Also, in the above embodiment, the example in which the second semiconductor laser element (multi-wavelength semiconductor laser element) is configured to include the infrared semiconductor laser element portion that emits infrared laser light and the red semiconductor laser element portion that emits red laser light was shown, but the present invention is not limited to that and the second semiconductor laser element may be configured to include a semiconductor laser element portion that emits laser light other than infrared or red. 
     Also, in the above embodiment, the example in which as the first semiconductor laser element, the blue-violet semiconductor laser element that emits blue-violet laser light is used was shown, but the present invention is not limited to that and the semiconductor laser element that emits laser light other than blue-violet may be used. 
     Also, in the above embodiment, the case in which the second semiconductor laser element (two-wavelength semiconductor laser element) is formed using a semiconductor substrate made of GaAs was shown, but the present invention is not limited to that and may be formed using a semiconductor substrate made of those other than GaAs. 
     Also, in the above embodiment, the case in which the first semiconductor laser element is formed using a semiconductor substrate made of GaN was shown, but the present invention is not limited to that and may be formed using a semiconductor substrate made of those other than GaN. 
     Also, in the above embodiment, the example in which the major face of the semiconductor substrate of the two-wavelength semiconductor laser element is inclined by an off angle of approximately 13° in the [ 011 ] direction from the ( 100 ) face was shown, but the present invention is not limited to that and the major face of the semiconductor substrate may be inclined by an off angle other than approximately 13°. 
     Also, in the above embodiment, the example in which the distance W 31  between the light emitting portion  12   a  of the blue-violet semiconductor laser element and the light emitting portion  31   a  of the two-wavelength semiconductor laser element was set to approximately 110 μm and the distance W 32  between the light emitting portion  31   a  and the light emitting portion  41   a  of the two-wavelength semiconductor laser element is set to approximately 110 μm was shown, but the present invention is not limited to that and the distance W 31  between the light emitting portion  12   a  of the blue-violet semiconductor laser element and the light emitting portion  31   a  of the two-wavelength semiconductor laser element and/or the distance W 32  between the light emitting portion  31   a  and the light emitting portion  41   a  of the two-wavelength semiconductor laser element may be set to the size other than approximately 110 μm. In this case, the distances W 31  and W 32  are preferably smaller than approximately 110 μm. 
     Also, the distance W 31  may be set smaller than the distance W 32 . By improving the mounting accuracy of the blue-violet semiconductor laser element and the two-wavelength semiconductor laser element on the sub-mount, the distance W 11  between the blue-violet semiconductor laser element and the two-wavelength semiconductor laser element may be made much smaller, and the distance W 31  can be easily made smaller than the distance W 32 . 
     Also, in the above embodiment, the example in which the blue-violet semiconductor laser element and the two-wavelength semiconductor laser element are mounted on the sub-mount was shown, but the present invention is not limited to that and the blue-violet semiconductor laser element and the two-wavelength semiconductor laser element may be mounted on a mounting member other than the sub-mount.