JP2003046204A - Semiconductor laser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor laser which can solve the problem of not being reduced in cost and mass-produced. SOLUTION: This semiconductor laser is constituted of first and second semiconductor laser chips 3 and 4 arranged on the surface 2 of a substrate 1 in a state where their light-emitting optical axes intersect each other at right angles and a reflecting section 6 vertically arranged on the substrate 1. The reflecting section 6 is arranged on the substrate 1 so that the reflecting surface 6a of the section 6 may be placed at an angle of 45 deg. from the light-emitting optical axis of one of the laser chips 4 and 6.

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.

[0002]

2. Description of the Related Art Semiconductor laser devices include CD-R, DV
It is used in optical pickups for recording and reproducing on various optical recording media such as D and S-DVDs, laser printers, and beam writing devices for digital copying machines.

Incidentally, for example, in a recording / reproducing apparatus using an optical recording medium, ideally, one recording / reproducing apparatus is used for a plurality of types of discs such as CDs, CD-Rs and DVDs.
It is preferable that the disk such as can record and reproduce.

However, with the laser light having a wavelength of 780 nm used in CDs and CD-Rs, the light spot is D
It is not possible to narrow down the size of the pits on the VD disc. On the other hand, the dye used in the CD-R disc is not reflected by the laser light of 635 nm or 650 nm having a short wavelength used in DVD, and is transmitted, and thus cannot be read.

Therefore, for example, one CD-R and one DVD
In order to enable recording / reproducing with one recording / reproducing apparatus, a short wavelength of 635 nm or 65 for reproducing DVD is required.
0nm red semiconductor laser chip and 780 for CD playback
An optical pickup incorporating a near-infrared semiconductor laser chip of 1 nm is required, and an integrated optical pickup in which two types of semiconductor laser chip chips are incorporated in one package is required for further downsizing of the device. Become.

Here, in order to incorporate the two light sources into one package to share the optical system, it is necessary to make the light emitting point intervals of the two semiconductor laser chip chips as close as possible, and the interval is 100 μm or less. Is preferred.

Therefore, in the past, as a semiconductor laser chip element having a narrow light emitting point interval, Japanese Patent Application Laid-Open No. 11-112089.
There is one described in the publication. As shown in FIG. 13, the first semiconductor laser chip 101 having an emission wavelength of 780 nm and the second semiconductor laser chip 102 having an emission wavelength of 650 nm are mounted on a submount by junction down. Semiconductor laser chip 101
The light emitting point 105 of the semiconductor laser chip 1 and the light emitting point 106 of the second semiconductor laser chip 102 are provided in a biased manner.
By arranging the light emitting points 105 and 106 of 01 and 102 so as to be substantially parallel and close to each other, the distance between the light emitting points is about 100 μm or less.

Further, a method has been proposed in which a light emitting point is artificially brought close to each other by utilizing a reflecting surface. For example, JP-A-11-
Japanese Patent No. 396884 discloses a method of bringing light emitting points close to each other by a submount having a triangular cross section. This will be described with reference to FIG. 14. Since the outputs B1 and B2 from the semiconductor lasers 112 and 113 are bent by the adjacent reflecting surfaces 114 and 115 by the submount 111 having a triangular cross section, the light emitting point is simulated. Can be close to each other.

[0009]

However, the above-mentioned conventional semiconductor diode in which the light emitting points are biased has a low yield, and a semiconductor laser chip and a reflection part of 45 ° are used to narrow the light emitting point interval. In particular, 4
There is a problem that it is not easy to form an inclined surface having a triangular cross section having an angle of 5 °, and stable mass production cannot be performed.

As described above, the conventional method of making the light emitting points close to each other by utilizing the reflecting surface is not a simple method suitable for mass production, and there is a problem that it cannot be realized at low cost. is there.

The present invention has been made in view of the above problems, and mass productivity of a semiconductor laser device in which the intervals between the light emitting points of a plurality of semiconductor lasers are pseudo-closed by using a reflecting surface,
The purpose is to reduce costs.

[0012]

In order to solve the above-mentioned problems, a semiconductor laser device according to the present invention is a semiconductor laser device in which first and second semiconductor lasers are arranged on the surface of a support so that their emission optical axes are orthogonal to each other. It is composed of a chip and a reflection part arranged perpendicularly to the support, and the reflection surface of the reflection part is arranged at an angle of 45 ° to the emission optical axis of either one of the two semiconductor laser chips. It is a thing.

Here, it is preferable that the emission wavelengths of the two semiconductor laser chips are different. In addition, it is preferable that the support and the reflection portion are formed of the same member. in this case,
It is preferable that the support and the reflection portion are made of silicon as a main material and are formed by anisotropic etching. Here, it is preferable that a light receiving element is formed on the support.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. A semiconductor laser device according to the first embodiment of the present invention will be described with reference to FIGS. 1 is a plan view of the semiconductor laser device,
2 is a front view of the semiconductor laser device, and FIG. 3 is a side view of the semiconductor laser device.

This semiconductor laser device has a first semiconductor laser chip 3 and a second semiconductor laser chip 4 which are arranged on the surface 2 of the support 1 so that the emission optical axes thereof are orthogonal to each other, and the bottom 5 is one step lower. Is provided with a quadrangular prism reflection part 6 inclined by 45 ° with respect to the emission optical axis of the second semiconductor laser chip. Here, the semiconductor laser chips 3 and 4 are connected to the metal wiring 12
It is fixed on top with Au—Sn eutectic solder 13 or the like.

With this structure, the emitted light 7 from the first semiconductor laser 3 goes straight, and the emitted light 8 from the second semiconductor laser chip 4 is folded back by 90 ° at the 45 ° reflecting portion. , Is emitted in the same direction in parallel with and extremely close to the emitted light 7 from the first semiconductor laser chip 3.

This semiconductor laser device will be described in more detail. As the support 1, SiC, Al having excellent thermal conductivity is used.
It is processed into a predetermined shape using N, a silicon substrate, or the like.
A silicon substrate or glass having an excellent surface property is used for the reflecting portion 6 of the quadrangular prism. First, gold is vapor-deposited on the surface to be the reflecting surface 6a and then cut out by dicing or the like into a predetermined shape.

The steps of the support 1 and the shape of the reflecting portion 6 are determined in consideration of the spread of the light of the semiconductor laser. That is, generally, the spread of the laser beam emitted from the semiconductor laser is about horizontal beam spread angle θ = 10 ° and vertical beam spread angle θ = 30 °. In this case, the divergence of the beam at the point 150 μm or 300 μm away from the emitting end is predicted as shown in Table 1.

[0019]

[Table 1]

Here, the first with the interval of the light emitting points set to 100 μm
The semiconductor laser device of the embodiment will be described with reference to the enlarged explanatory view of FIG. When the emission end width w _{3 of} the first semiconductor laser chip 3 is 300 μm, the cavity length is 450 μm, and when the emission end width w _{4 of} the second semiconductor laser chip 4 is 250 μm, the cavity length is 4 μm.
The light emitting point 9 of the first semiconductor laser and the light emitting point 10 of the second semiconductor laser chip are each at the center of the emission end of 50 μm.

The support 1 as a submount has a high thermal conductivity and excellent workability, is AlN, and the reflecting portion 6 is a silicon quadrangular prism, and gold is vapor-deposited on at least the reflecting surface 6a.

The emission end of the first semiconductor laser chip 3 and
Distance d to the end of the opposing support 1_ThreeIs 300 μm
To do. The optical axis of the second semiconductor laser chip 4 is
A light emitting point 1 orthogonal to the emission optical axis of one semiconductor laser 3
Position 0_FourIs the optical path length d _ThreeDistribute so that it is 1/2 of
Place.

Now, assuming that the optical path length of the second semiconductor laser chip 4 is equal to the optical path length of the first semiconductor laser chip 3, the emission end of the second semiconductor laser chip 4 and the first semiconductor laser chip 3 are The distance x from the optical axis is set to 50 μm in consideration of the light emitting point interval L (100 μm) and the distance d ₄ (150 μm) between the light emitting point 10 and the end of the support 1.

A step h between the surface 2 and the bottom 5 of the support 1
₀ is 300 from the emission end so that the light emitted from the semiconductor laser chips 3 and 4 is not kicked by the bottom 5.
More than half of the vertical spread at 80 μm (80 μm),
In consideration of the safety level, we have selected about 120 μm, which is about 1.5 times.

The shape of the reflection portion 6 is 250 μm square, and its height h is 160 μm or more in consideration of the step h ₀ of the support 1 and the light spread in the vertical direction of the semiconductor laser, and about 200 μm in consideration of margin and handling. You have selected. The reflecting portion 6 is arranged at a predetermined position by using a collet, and is quickly fixed by using an ultraviolet ray ultraviolet curing resin or the like.

As described above, the first and second semiconductor laser chips arranged so that the emission optical axes thereof are orthogonal to each other on the surface of the supporting body, and the reflecting portion arranged perpendicularly to the supporting body are provided. The reflecting surface of the two semiconductor laser chips is arranged at an angle of 45 ° with respect to the emission optical axis of one of the two semiconductor laser chips, and the reflecting surface of the reflecting portion is brought closer to the second semiconductor laser side, thereby separating the two light emitting points. It is possible to make it narrower, and it is not necessary to form the reflecting portion in a triangular shape in cross section.
Cost reduction can be achieved.

In the description, the shape of the reflecting portion is a quadrangular prism, but the number of reflecting surfaces is one, and the shape of the reflecting portion is not limited to the quadrangular prism.

Next, a semiconductor laser device according to the second embodiment of the present invention will be described with reference to FIGS.
5 is a plan view of the same semiconductor laser device, FIG. 6 is a front view of the same semiconductor laser device, and FIG. 7 is a side view of the same semiconductor laser device.

In this embodiment, a support and a reflection portion (mirror) are integrally formed by using silicon and its anisotropic etching. That is, the support 1 made of silicon
The first semiconductor laser chip 3 and the second semiconductor laser chip 4 are arranged on the surface 2 of the so that the emission optical axes thereof are orthogonal to each other, and the reflecting portion 16 formed by the (111) plane of silicon is formed on the bottom portion 5 thereof. Are integrally formed. The reflecting portion 16 has a reflecting surface 16 a formed perpendicularly from the bottom portion 5 at an angle of 45 ° with respect to the emission optical axis from the second semiconductor laser 4.

Here, details of the semiconductor laser device according to the second embodiment having a light emitting point interval of 100 μm will be described in detail with reference to FIG. Now, the emission end width w _{3 of} the first semiconductor laser chip 3 is 300 μm and the cavity length is 450 μm. The second semiconductor laser chip 4 is the emission end width w ₄ 300 μm and the cavity length is 450 μm. The light emitting point 9 and the light emitting point 10 of the second semiconductor laser chip are respectively at the center of the emission end.

A (110) silicon substrate is used for the support 1, and the distance d ₃ from the emitting end of the first semiconductor laser chip 3 to the end of the support is 300 μm. 4, the optical axis of which is orthogonal to the emission optical axis of the first semiconductor laser chip 3, and the position d _{4 of} its light emitting point
Is arranged to be 1/2 of the optical path length.

A step h between the surface 2 and the bottom 5 of the support 1
₀ is 300 from the emission end so that the light emitted from the semiconductor laser chips 3 and 4 is not kicked by the bottom 5.
More than half of the vertical spread at 80 μm (80 μm),
In consideration of the safety level, we have selected about 120 μm, which is about 1.5 times.

The reflecting portion 16 formed by anisotropic etching of silicon is arranged between the optical axis of the first semiconductor laser chip 3 and the second semiconductor laser chip 4, and its size is a reflecting surface 16a having a width of 100 μm and a thickness. The thickness is about 50 μm, and gold is vapor-deposited on the reflecting surface 16a to obtain a high reflectance.

The arrangement of the reflecting portion 16 and the second semiconductor laser chip 4 is determined as follows based on the first semiconductor laser chip 3. Now, when the optical path length of the light from the second semiconductor laser chip 4 is made equal to the optical path length from the first semiconductor laser chip 3, the reflecting portion 16 is 100 μm which is the target light emitting point interval from the first semiconductor laser optical axis. The second semiconductor laser chip 4 is arranged on the side of the second semiconductor laser, and the end portion of the second semiconductor laser chip 4 is arranged at a position 150 μm away from the reflecting portion 16.

In this semiconductor laser device, by bringing the reflecting portion closer to the second semiconductor laser chip side,
The interval between the two light emitting points can be narrowed.

Next, a method of manufacturing the semiconductor laser device according to the second embodiment will be briefly described with reference to FIG. First, as shown in FIG. 3A, a silicon substrate 5 having a crystal plane orientation (110) in which a mirror surface of a (111) plane is formed vertically.
1 is used to mask a region of the silicon substrate 51 where the reflective portion 16 is formed with a mask 5 such as a SiO ₂ film or a Si ₃ N ₄ film.
Masked with 2, for example HF: NHO ₃ : CH ₃ C
By etching with OOH to a thickness of 50 μm, a surface 2 of the support 1 for die-bonding the semiconductor laser chips 3 and 4 is formed as shown in FIG.

Next, the entire surface of the silicon substrate 51 is again covered with Si.
An O ₂ film or a Si ₃ N ₄ film or the like is formed to a thickness of 0.1 to 0.5 μm and patterned by dry etching or wet etching. As shown in FIG. The portion corresponding to the die bonding surface and the reflection portion 16 is masked with the mask 53.

Then, as shown in FIG.
Etchant KOH: IPA: H _TwoO to a predetermined depth
After etching the silicon substrate 51 with,
As shown, the mask 53 is removed, and the reflecting portion 16 is integrated.
The formed support 1 is obtained.

Specifically, the depth is about 120 μm in consideration of the vertical light spread expected from the distance d ₃ from the end of the semiconductor laser chip to the end of the support. Therefore, the height of the reflecting portion 16 is 5 times that of the previous etching amount.
170 of the sum of 0 μm and 120 μm of the anisotropic etching amount
It becomes about μm.

By integrally forming the support and the reflecting portion in this way, the mounting cost can be reduced.

Next, a semiconductor laser device according to the third embodiment of the present invention will be described with reference to FIGS. 10 is a plan view of the semiconductor laser device,
FIG. 11 is a front explanatory view of the same semiconductor laser device, and FIG. 12 is a side view of the same semiconductor laser device.

In this embodiment, as in the second embodiment, the support 1 and the reflecting portion 16 are integrally formed of a silicon substrate, and the support 1 is a photodiode for monitoring the light output from the semiconductor laser chips 3 and 4. 15 and 15 are provided.
The photodiodes 15 and 15 are semiconductor laser chips 3 and
It is formed at the back of No. 4.

With such a structure, the conventional monitor photodiode can be omitted, and the mounting cost can be further reduced.

[0044]

As described above, according to the semiconductor laser device of the present invention, the first and second semiconductor laser chips arranged on the surface of the support so that the emission optical axes thereof are orthogonal to each other, and the support It is composed of a reflective part that is arranged perpendicular to the body,
Since the reflecting surface of the reflecting portion is arranged at an angle of 45 ° on the emission optical axis of either one of the two semiconductor laser chips,
The light emitting points of the two semiconductor laser chips can be brought close to each other, the reflecting portion can be produced at a lower cost than before, and it is not necessary to use a special semiconductor laser chip with the light emitting points biased. Easy mounting, high yield, and low cost.

Here, since the emission wavelengths of the two semiconductor laser chips are different, it is possible to easily construct an optical pickup using lasers of different wavelengths, for example.
Further, since the support and the reflection portion are formed of the same member, cost reduction can be achieved. In this case, since the support and the reflection part are made of silicon as a main material and are formed by anisotropic etching, the support and the reflection part can be easily integrally formed. Further, by forming the light receiving element on the support, the mounting cost can be further reduced.

[Brief description of drawings]

FIG. 1 is an explanatory plan view of a semiconductor laser device according to a third embodiment of the present invention.

FIG. 2 is a front explanatory view of the semiconductor laser device.

FIG. 3 is a side view of the same semiconductor laser device.

FIG. 4 is an enlarged explanatory view of a main part of FIG.

FIG. 5 is an explanatory plan view of a semiconductor laser device according to a second embodiment of the present invention.

FIG. 6 is a front explanatory view of the semiconductor laser device.

FIG. 7 is a side view of the semiconductor laser device.

FIG. 8 is an enlarged explanatory view of a main part of FIG.

FIG. 9 is an explanatory diagram illustrating a step of forming a support body and a reflection section of the same embodiment.

FIG. 10 is an explanatory plan view of a semiconductor laser device according to a third embodiment of the present invention.

FIG. 11 is a front explanatory view of the semiconductor laser device.

FIG. 12 is a side view for explaining the same semiconductor laser device.

FIG. 13 is an explanatory diagram of a conventional semiconductor laser device.

FIG. 14 is an explanatory view showing another example of a conventional semiconductor laser device.

[Explanation of symbols]

1 ... Optical disc substrate, 2 ... Light incident surface, 3 ... Information recording surface,
4 ... taper surface, 11 ... fixed side mirror surface block, 12 ... stamper, 21 ... movable side mirror surface block, 22 ... outer peripheral ring,
23a, 23b ... Clearance, 25 ... Outer ring member, 26 ... Inner ring member, 27 ... Bearing ball, 2
8 ... Holding member, 31 ... Cavity.

Claims (5)

[Claims] 1. A first semiconductor laser chip and a second semiconductor laser chip arranged on a surface of a support body so that emission optical axes thereof are orthogonal to each other, and a reflection section arranged perpendicularly to the support body. The semiconductor laser device is characterized in that the reflection surface of the portion is arranged at an angle of 45 ° with respect to the emission optical axis of one of the two semiconductor laser chips. 2. The semiconductor laser device according to claim 1, wherein the two semiconductor laser chips have different emission wavelengths. 3. The semiconductor laser device according to claim 1 or 2, wherein the support and the reflecting portion are formed of the same member. 4. The semiconductor laser device according to claim 3, wherein the support and the reflection portion are made of silicon as a main material and are formed by anisotropic etching. 5. The semiconductor laser device according to claim 4, wherein a light receiving element is formed on the support.