JPS63237490A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To mount a plurality of semiconductor laser chips with different characteristics, and make the luminous spot distance less than or equal to 100mum, by fixing a pair of semiconductor laser chips so as to be separated on two surfaces facing each other at a distance. CONSTITUTION:A pair fo semiconductor laser chips 1 and 2 are fixed so as to be separated on surfaces 11 and 13 facing each other at a distance, and electrode surfaces 5 and 7 are arranged so as to be parallel to each other at opposing positions, so that the distance between active layers 3 and 4, i.e., the luminous spot distance can be easily made 50mum. Therefore, as a lens having a smaller visual field is applicable, an optical head can be made much smaller and more light-weight. Even if the luminous spot distance is made 50mum, the semiconductor chips 1 and 2 are completely electrically separated. Further, as they are arranged at distant positions on a ?-shaped block 31, the interference between the laser chips 1 and generates neither electrically nor thermally. Thereby, superfluous remedies for interference are not required.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor laser device comprising a plurality of independent semiconductor laser chips in which laser beams are located close to each other.

[Conventional technology]

Currently, research is being actively carried out aimed at increasing the speed and performance of optical disk devices and laser beam printers. Regarding optical disk devices, methods have been considered that use two light spots to realize an error check function immediately after recording, a recording/reproducing/erasing function, or a parallel processing function of recording/reproducing two tracks simultaneously. Furthermore, in laser beam printers, it has been considered to improve the recording speed by similarly using a plurality of light spots. The use of semiconductor laser arrays is being considered as one means for realizing the above method. Conventional semiconductor laser devices equipped with the above-mentioned semi-four-body laser array include, for example, Proceedings of the 47th Japan Society of Applied Physics Academic Conference, 2
7p-T-10, p.

159 (1986), there are monolithic types and hybrid types. The monolithic type is an array of multiple semiconductor lasers on one semiconductor laser chip, and the emission spot spacing is usually 110 mm.
The minimum limit is about 0I1.

On the other hand, the hybrid type is one in which a plurality of semiconductor laser chips are arranged in parallel on a mount plane, and the minimum interval between the light emitting spots is about 150.

In addition, in any type of conventional semiconductor laser device, the oscillation wavelength of a plurality of semiconductor laser chips included in the device is the same.

[Problem that the invention seeks to solve]

In optical disk devices and laser beam printers, the distance between the focused spots of multiple focused laser beams is several points.
It is required to take ~several tens of times.

Therefore, although it depends on the image magnification of the focusing optical system used in the optical disk device or the laser beam printer, it is desirable that the interval between the light emitting spots of the semiconductor laser device is 100 or less. This is because the effective field of view of the optical lens system connected to the semiconductor laser device is limited, and the lens must be used in a paraxial region free of aberrations. This requirement becomes even more severe when trying to downsize the optical lens system.

In the case of conventional monolithic semiconductor laser arrays, if the emission spot interval, that is, the array interval of semiconductor lasers, is set to 1100I or less, the lasers will thermally and electrically interfere with each other, making it difficult to modulate the lasers independently. become. Therefore, the laser emission spot interval is set to 1
There is a big technical problem in reducing the value to 00p or less.

On the other hand, in the conventional hybrid type in which semiconductor lasers are arranged in parallel on a plane, the laser chip must be cut very close to the laser active layer.

A problem arises in that strain deterioration occurs in the laser, resulting in a shortened laser life. Therefore, the interval between light emitting spots cannot be narrowed to 1100 II or less.

However, in order to perform recording and playback in real time without waiting for the rotation of the disc in an optical disc device, it is necessary to
At least two semiconductor lasers are required, one with high output for erasing and one with low noise for reproduction. Furthermore, if the oscillation wavelengths of the semiconductor lasers are the same, the beams must be spatially separated in the signal detection system, which complicates the optical system and is disadvantageous in terms of miniaturization and cost reduction. However, in the monolithic type, the wavelength,
It is extremely difficult in the semiconductor manufacturing process to create seven laser layers with different output and noise characteristics.

An object of the present invention is to stack a plurality of semiconductor lasers with different characteristics, and to set the emission spot interval of the semiconductor lasers to 10.
The object of the present invention is to obtain a semiconductor laser device that can reduce the power to 0ρ or less.

[Means for solving problems]

The above object is achieved in a hybrid semiconductor laser device by adopting a mounting structure in which two semiconductor laser chips are separately fixed to two surfaces facing each other with a space between them.

[Function] According to the above solution, the active layers of two semiconductor lasers can be brought close to each other with a small space between them.

In other words, with a hybrid semiconductor laser device,
Two semiconductor laser chips facing each other across a space.
By separately fixing them to two surfaces, it is possible to achieve
The distance between the light emitting spots of the semiconductor laser can be narrowed to about twice the distance between the electrode and the active layer, and a distance of 100 or less can be easily realized. Furthermore, since it is a hybrid type, it is possible to mount semiconductor lasers with different characteristics. Note that since the semiconductor lasers are each mounted on the apparatus at independent and separated positions, thermal and electrical interference between the lasers does not occur, and each laser can be modulated independently.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory diagram showing a first embodiment of a semiconductor laser device according to the present invention, in which (a) is a plan view, (b) is a side view, and
The figure is an enlarged view of the center of Figure 1, (a) is a plan view, (b)
is a side view, FIG. 3 is a diagram showing an example in which the above embodiment is applied to an optical disk device, FIG. 4 is an explanatory diagram showing a second embodiment of the present invention, and FIG. 5 is a third embodiment of the present invention. FIG. 6 is a diagram showing a fourth embodiment of the present invention. 1 shown in Figure 1.
The embodiment is a semiconductor laser device for an optical disk device.

1 and 2, semiconductor laser chips 1 and 2 are mounted on submounts 9 and 10, respectively, submount 9 is mounted on block 31 via mount 30, and submount 10 is mounted directly on block 31.
It is installed in 1. Further, a photodiode 21 for monitoring laser light is also mounted on the block 31.

Terminals 23.24.25 are respectively glass 27.28.2
9, it is airtightly attached to the base body 34. block 31
and the cap 33 into which the lens 32 is fitted and the terminal 26
is welded to the base body 34.

The base body 34 is provided with screw holes 35 and 36.

The above block 31 and each terminal 23, 24, 25, 26
The central portion 37 including the cap 33 and the base 34 are hermetically sealed.

The semiconductor laser chip 1 is made of aluminum with an oscillation wavelength of 780 nm.
It is an lGaAs semiconductor laser, has low noise characteristics, and is used for reproducing optical discs. The laser beam is emitted from the position of the active layer 3 shown in FIG. The n-side of the laser chip 1 is an electrode surface 5, and the p-side is an electrode surface 6. The distance between the electrode surface 5 and the active layer 3 is about 5-.

On the other hand, the semiconductor laser chip 2 has an oscillation wavelength of 830 nm.
It is a flGaAs semiconductor laser, has high output characteristics, and is used for writing and erasing optical discs.

The p-side of the semiconductor laser chip 2 is an electrode surface 7, and the n-side is an electrode surface 8. The laser beam is applied to the active M at a distance of approximately 5 − from the electrode surface 7.
It emits from position 4.

Submounts 9 and 10 are made of SiC ceramic, and their surfaces are partially coated with Au/Ni/Ni/Ni for electrical wiring.
Ti metallization is applied (the metallized surface is 11.
12.13.14).

The photodiode 21 is a 0.8 cape wavelength band SiP IN photodiode, whose upper surface is a light-receiving surface, and monitors the optical power of the laser beams emitted from the semiconductor laser chips 1 and 2 in a time-sharing manner as described below. .

Since the emission angle of the laser beam is wide, ranging from 10 to 40', and the light from both semiconductor lasers is incident on the photodiode 21, the two laser beams cannot be spatially separated.

Therefore, as it is, it is impossible to independently monitor the optical power of each laser beam. Therefore, by sequentially oscillating semiconductor lasers one by one within a specific time domain, the optical power of each laser beam can be temporally separated and independently monitored using one photodiode, for example. In the case of optical discs for recording code data for computers, it is the time that the light spot runs on the alternating sector in one track or the alternating trunk in one track, and in the case of optical discs for video, it is the time for one track rotation. One vertical synchronization and retrace period can be used as a time domain for monitoring the power of the laser beam. Within this time domain, if you first oscillate only one semiconductor laser and monitor the optical power, then oscillate only the other semiconductor laser and monitor the optical power, you can time-divisionally monitor the power of each laser beam. Can be done independently.

The terminals 23, 24, 25, 26, mount 30, block 31, cap 33, and base 34 are made of, for example, Kovar or Cu, and their surfaces are plated with Au/Ni. The lens 32 is, for example, a double-sided aspherical glass lens. Depending on the beam characteristics of the laser beam and the specifications of the optical system, the surface shape of the lens 32 is processed into a rotationally symmetrical ellipsoid, paraboloid, or hyperboloid, or a rotationally asymmetrical surface having a radius of curvature. With the lens 32,
The laser beams emitted from the semiconductor laser chips 1 and 2 become unbiased parallel beams with spherical aberrations corrected and are emitted from the semiconductor laser device. Needless to say, it is not necessary to install the lens 32 when there is no need to make the light beam into a parallel light beam or when an optical system for making the light beam into a parallel light beam is provided separately.

Semiconductor laser chips 1 and 2, submounts 9 and 10, submount 9 and mount 30. Between the submount IO and the block 31, between the mount 30 and the block 31, and between the photodiode 21 and the block 31,
All bonding is done with solder, and solders with different melting points depending on the 5 assembly processes, such as Au-3n and Pb-8, are used.
n, In-3n alloy, etc. were used.

Electrical wiring of the semiconductor laser chip 1.2 was performed as follows. @Pole surface 5 is connected to wire 15, metallized surface 12 is connected to terminal 23 via wire 16, electrode surface 6 is connected to mount 30 and block 31 through metallized surface 11 and wire 17. The terminals 26 pass through the base body 34 respectively.
It is grounded to. The electrode surface 7 is grounded to the terminal 26 via the wire 18, the metallized surface 14, the wire 19, and the block 31° base 34, respectively. The electrode surface 8 is connected to a terminal 24 via a metallized surface 13 and a wire 20. A wire 22 is connected to the light receiving surface side of the photodiode 21.
It is connected to the terminal 25 via the block 31 and the base 34 on the opposite side to the terminal 26 . wire 1
5.16.17.18.19.20.22 are all Au
It is a line.

Next, a general process for assembling nine semiconductor laser devices will be explained. First, the photodiode 21 is bonded to a predetermined position of the block 31 using Au-5n solder. Next, each of the semiconductor laser chips 1 and 2 is mounted on a submount 9.
．． 10 with Au-5n solder. Place the submount 9 in place on the mount 30, and place the submount 1 in place.
0 to a predetermined position of the block 31 using Pb-8n solder. Then, while moving the mount 30 in close contact with the block 31 and moving it laterally, the position of the active layer 3 with respect to the active layer 4 is adjusted, and then fixed with In-8n solder. The block 31 may be welded to the base body 34 after the above process is completed, or may be welded in advance before the above process. Other types of solder may be used depending on the order of the steps and the heat resistance specifications of the semiconductor laser device.

The mounting position of the semiconductor laser chip 2 is as follows.

The mounting of the semiconductor laser chip 1 is shifted from the position by several to several tens of points in the laser beam emission direction. This is laser 1
．． This is to correct chromatic aberration since the refractive index of the glass material of the lens 32 differs depending on the wavelength of the lens 32. Since the refractive index difference of the lens 32 is approximately proportional to the wavelength difference between the semiconductor lasers 1 and 2, the shifting distance is also approximately proportional to the wavelength difference.

In the assembly process, if the semiconductor laser chip 2 is shifted beforehand when attached to the submount 10, then the semiconductor laser chip 1, the submount 9, 10, . The upper surfaces of the mount 30 and block 31 may be aligned and assembled.

The optical head for optical disks according to the present embodiment described above is capable of low-noise reproduction and high-output writing and erasing in real time. Moreover, since the same optical system is required for two semiconductor laser chips, the optical head can be made smaller.

Further, as shown in this embodiment, a pair of semiconductor laser chips 1.2 are separated from each other by two surfaces 11.1 facing each other with a space in between.
If the electrode surfaces 5.7 are arranged in substantially parallel and opposing positions, the distance between the active layers 3.4, that is, the distance between the light emitting spots, can be easily increased to 50. It can be done. Therefore, since a small lens with a smaller effective field of view can be used, the optical head can be further reduced in weight and size.

Here, even if the emission spot interval is set to 50tIrR, the semiconductor laser chips 1 and 2 are completely electrically separated and are mounted at separate positions on the concave-shaped block 31, so the above-mentioned Lasers 1 and 2 do not interfere with each other either electrically or thermally, and therefore, unlike conventional semiconductor laser devices, there is no need to take extra measures against interference.

Furthermore, since the oscillation wavelengths of the two semiconductor laser chips 1.2 are different, the two laser beams can be easily separated in the signal detection system using an optical wavelength filter. Therefore, a complicated optical system can be omitted when the oscillation wavelengths are the same.

From the above points, according to this embodiment, the size of the optical head for optical disks can be reduced to less than 1/2 of the conventional size, and the weight of the moving part optical system is reduced, allowing high-speed operation of the actuator. access time is about 30%
FIG. 3 shows an example in which the semiconductor laser device of the first embodiment is applied to an optical disk device. Inside the semiconductor laser device 71, there are a laser chip 101 (hereinafter referred to as LDI) with an oscillation wavelength of 830 nm and high output, and a laser chip 780
Two semiconductor laser chips, a laser chip 102 (hereinafter referred to as LD2) having a low noise of 100 nm, are arranged close to each other as shown in the first embodiment (a partially enlarged view is shown in the upper right circle). show). The above two semiconductor laser chips LD
The light emitted from I and LD2 is passed through the collimating lens 7.
2 and beam shaping optical system 73, it becomes a parallel light beam with a circular intensity distribution. Here, the beam shaping optical system 73 may be omitted depending on specifications. The parallel light beam passes through a beam splitter 74 and a λ/4 plate 75, and is focused on a recording film 701 on an optical disk 77 by a focusing lens 76.
The beam is narrowed down to a focused spot with a diameter of approximately 17M.

The focusing spot SP of the LDI focuses on the track 8 of the rotating optical disk 77 with respect to the focusing spot SP2 of the LD2.
4, the SP performs recording (writing/erasing) of information, and the SP performs reproduction and error checking (a partially enlarged view is shown in the circle at the bottom left).

The above SP1 and S on the track 84 of the optical disc 77
The distance D from P2 is the distance between the light emitting spots between LDI and LD2, the collimating lens 72, and the aperture lens 76.
It is determined from the lateral multiplication factor m1 of the aperture optical system consisting of the following. Focal point m of collimating lens 72, = fp/fc
(1) Therefore, the relationship between the focused spot interval D1 on the optical disk 77 and the emission spot interval d of the semiconductor laser is Dz=mzdz=(fr/fc)dt (2)
is given by The specifications of D8 in the optical disk device are as follows:
It is determined in consideration of the image field of the diaphragm lens 76, the signal processing method, the disk format, etc.

In practice, D-work is less than 50, preferably 20. By the way, the focusing optical system has chromatic aberration, so if laser beams with different wavelengths are focused using the same optical system, the focal positions of the condensing spots SP1 and SP2 will be in the direction of laser beam travel. It shifts. Since focus control is performed on one of the focused spots, the other focused spot will be out of focus. In order to prevent the above-mentioned focus shift from occurring, it is necessary to set the LDI and LD2 in advance so as to shift them back and forth with respect to the laser beam emission direction, and to shift the light emission spots of the two lasers in the optical axis direction. .

Furthermore, the chromatic aberration of the entire aperture optical system consisting of the aperture lens 76 and the collimator lens 72 is C(x/r+m).
, the oscillation wavelength difference between LD1 and LD2 is Δλ (nm)
Then, the initial focal position shift D2 is D2=Δλ·C(3). The vertical image magnification m2 of the aperture optical system is m z =
(f F/ f c)” (4) Therefore, the required positional shift amount d2 for mounting LDI and LD2 is d 2 = D z / m z = (Δλ-C)/
(f F/ f c)”. Thus,
If the LDI is installed d2 behind LD2 in the laser beam emission direction, the optical disk 7 of LDl and LD2
The focal positions on 7 coincide. However, the value of d2 is LD
I.

This is a value when there is no astigmatism in both LD2.

Actually, the laser (LD) with an oscillation wavelength of 780 nm was used.
2) had astigmatism, so it is necessary to correct d2. The light emitting point of LD2 (considered as the center position of the circle of least confusion) is considered to be inside the laser chip from the laser end face by 1/2 of the astigmatism, so if the astigmatism intersection of LD2 is ΔZ, then LDI and When installing LD2, shift amount d, / is d, '=d, + (AZ/2) (6)
If there is astigmatism in both LDl and LD2.

d,'=d,+(ΔZS−ΔZL)/2. However, Δzs is the astigmatism of the LD2 that oscillates at a short wavelength, and ΔZL is the astigmatism Ll'i difference of the LDI that oscillates at a long wavelength.

Next, the distance between the condensed spots and the positional shift amount d 2 / of LDI and LD2 are calculated using equations (2) and (6). For example, f F=3.31+111. f c=
8.75mm, d, = 50Ilrs, c = 0.0
54/nm, Δλ = 830-780 = 50nm,
ΔZ=16. In the case, Dx=19IM, d, /=26−
It is. The above value of D□ is sufficiently suitable for real-time recording and reproduction of optical discs. The value of d2' is a value that can be sufficiently controlled in the process of fixing the LDI and LD2 to the semiconductor laser device. Actually, when an optical disk device was assembled according to the above numerical values, s
The focal lengths of pL and SF3 are the same, and good focusing spot characteristics are obtained.

Now, the two wavelengths of light reflected from the optical disk 77 are
reflected by the beam splitter 74 and passed through the optical wavelength filter 7
The wavelengths are separated by 8. For example, wavelength λ = 830
When using an optical wavelength filter where nm is total transmission and wavelength λ = 780 nm is total reflection, λ = 780 nm is used for detection optical system 79.
Only the light of 830 nm is sent to the voltage detection optical system 80 at λ=78
Only 0 nm light is incident. In order to further improve the wavelength separation characteristics, methods such as (1) using two optical wavelength filters 78 or (2) using a filter with wavelength separation films on both sides may be used. The output of the detection optical system 79 enters a signal processing circuit 81 to obtain a light point control signal for autofocus, tracking, etc., or address information recorded in advance on the disk. On the other hand, the output of the detection optical system 80 is input to a signal processing circuit 82 to perform recording reproduction and error checking. The semiconductor laser device 71 is controlled by a drive circuit 83.

During recording, the LDI is pulse-modulated by the drive circuit 83 according to the recorded (write/erase) information, and the LD2 is driven by DC at low output. Check. During reproduction, both LDI and LD2 are driven with low output DC current, and while a light spot control signal is obtained from the signal processing circuit 81, a reproduction signal is obtained from the signal processing circuit 82. For reproduction, there is also a method in which both light spot control and reproduction are performed using only the LD2 without causing the LDI to oscillate. LDl, LD2 and signal processing circuit 81.82
The role of may change depending on the signal processing method.

In the embodiment of the optical disk device described above, the low-noise laser with an oscillation wavelength of 780 nm used as the LD 2 is suitable for signal reproduction in that it does not require means such as high-frequency superposition. It had the disadvantage of large aberrations. For this shortcoming, collimating lens 72
This problem can be sufficiently overcome by setting the numerical aperture to 1, for example, 0.2 or less, so there is no problem as an optical disk device.

The above describes the first embodiment of the present invention and an example in which the same is applied to an optical disk device. The present invention is not limited to the above-mentioned components, specifications, methods, etc., and can be applied to semiconductor lasers or other devices depending on the application. It is possible to change the specifications of peripheral parts. In this example, the two surfaces on which a pair of semiconductor laser chips are fixed separately are not necessarily two parallel planes, but the semiconductor laser chips are fixed on mutually inclined or curved surfaces. Depending on the specifications of the optical system following the semiconductor laser device, this may occur depending on the case. Furthermore, the position at which the semiconductor laser chip is fixed onto the surface can be arbitrarily selected. Although the blocks used in this embodiment have a concave shape, depending on the assembly process, assembly equipment, etc., other block shapes 1, such as two rectangular prism blocks, may be used. In this example, two semiconductor lasers have an oscillation wavelength of 780n.
Although an 830 nm low noise laser and an 830 nm high output laser were used, any combination of these characteristics may be used. wavelength, power,
Depending on the purpose, the noise characteristics may be the same. Also,
The two lasers may have different emission distributions.

The present invention is naturally applicable not only to write-once type and magneto-optical type optical disks but also to phase-change type reversible optical disks in which one side of the semiconductor laser is used for rapidly cooling recording and the other side is used for slowly cooling and erasing. Regarding the photodiode, use a shielding plate etc.
It is also possible to spatially separate the two laser beams and monitor the power of the two lasers independently. Furthermore, the application of the present invention is not limited to disks; for example, the present invention can be applied to wavelength-multiplexed light by making the emission spot interval closer to each other and changing the lens to one with an appropriate focal length in the same configuration as this embodiment. It can also be used for communication. moreover.

Instead of a semiconductor laser chip, an optoelectronic integrated circuit that integrates a semiconductor laser, a photodiode, and their driving circuit is used.
It goes without saying that the effects of the present invention can be fully exhibited even if ted circuits (abbreviated as 0EIC) are used.

The second embodiment shown in FIG. 4 describes a semiconductor laser device for optical disk parallel transfer.

The configuration is such that four of the first embodiments described above are arranged side by side.

Eight semiconductor lasers 38 and 39 are mounted on two blocks 41 via two submounts 40, respectively. 1! Partially metallized surfaces (not shown) on the submount 40 from eight semiconductor lasers 38 and 39
and are connected to eight terminals 42 via eight wires, respectively, allowing independent modulation of the laser. The four lasers 38 in the same row are low noise lasers with an oscillation wavelength of 780 nm, and the four lasers 39 in the other row have an oscillation wavelength of 830 nm.
This is a high output laser.

The combination of opposing lasers 38 and 39 creates four pairs of lasers. Regarding a pair of lasers, the lasers are separately fixed to two surfaces facing each other across a space, and the electrode surfaces of the lasers are arranged to face each other. A pair of opposing semiconductor lasers performs real-time recording and reproduction of an optical disk as in the first embodiment.Adjacent lasers having the same oscillation wavelength track different positions on the optical disk. The mounting positions of each laser were of course taken into consideration, such as chromatic aberration and the track pitch of the optical disc. The reason why the row of lasers 38 and the row of lasers 39 are diagonally shifted is also for tracking position adjustment.

According to this embodiment, recording and reproduction can be performed simultaneously on four tracks of an optical disc, and four-parallel transfer is possible, resulting in an effect of increasing the transfer speed by four times. Furthermore, it goes without saying that if the number of lasers is multiplied, the transfer speed will be further improved.

In the semiconductor laser device of the third embodiment shown in FIG. 5, two semiconductor lasers 43 and 44 are integrated by bonding electrode surfaces 48 and 49 close to the active layer 45 and 46 to each other.

The electrode surface 50 is bonded to the metallized surface 51 on the surface of the mount 520. The electrode surface 47.49 and the metallized surface 51 are connected to terminals 56.5 by wires 53.54.55, respectively.
7.58 electrically connected. If terminal 57 is grounded, independent modulation of lasers 43 and 44 is possible. According to this embodiment, the simultaneous oscillation state of the semiconductor lasers 43 and 44,
It is possible to transmit 2-bit information in four states: oscillation state 43, oscillation state 44, and non-oscillation state, and is used, for example, in optical communication.

Furthermore, by simultaneous oscillation, a single device can output twice the optical output of the conventional device, making it effective as a high-power semiconductor laser device.

The fourth embodiment shown in FIG. 6 is a semiconductor laser device for a laser beam printer. Semiconductor lasers 59 and 60 mounted on mounts 66 and 67, respectively, are bonded via an insulating layer 63. The semiconductor laser 59
and 60 both have an oscillation wavelength of 830 nm.
This is a GaAs-based high-output laser. The above insulating layer 6
3, an electrical insulating material with low thermal conductivity was used.

Note that the lasers 59 and 60 are not symmetrical, and the positions of the active layers 61 and 62 are offset from the center.

This is because the cutting operations performed by the lasers 59 and 60 during chip formation are intentionally shifted to such an extent that strain deterioration does not occur in the active layers 61 and 62. This made it easier to bond the wires 64 and 65 for electrical wiring.

According to this embodiment, it is possible to obtain a light emitting spot spacing that was impossible with conventional semiconductor laser devices.

That is, the distance between the active layers 61 and 62 in the vertical direction of the drawing is set to about 1
0 Cape, I was able to reduce the horizontal spacing of the drawing to approximately so, m4. By using this device and scanning the laser beam in the horizontal direction of the drawing while independently modulating the lasers 59 and 60, it is possible to print two lines in one scan, compared to the conventional rule.
The printing speed is twice as fast compared to the Beam printer. Furthermore, since the interval between the light emitting spots is sufficiently small, the size of the scanning optical system connected to one device is almost the same as in the case of a laser beam, and can be made lighter and smaller.

By the way, the two lasers 59 and 60 are bonded together via an insulating layer 63, and the active J1, which is a heat generation source,
Since 61 and 62 are approximately 50 IIm apart, no thermal and electrical interference between the lasers 61 and 62 occurs. However, since the 50-active layer is separated, it is necessary to synchronize the modulation of the two lasers 59,60 when printing. Therefore, when two scanning beams pass through the light-receiving surface of the photodiode (6) using a photodiode in the control system, two electric pulses are generated. Since the time difference between the two electric pulses corresponds to the distance between the active layers 59 and 60 in the horizontal direction of the drawing, the laser 59
．． Synchronization can be achieved by shifting and adjusting the timing of modulation between 60 and 60 degrees.

It goes without saying that if the apparatus of this embodiment is multiplied, the speed of the laser beam printer can be further increased. Furthermore, this embodiment can be applied not only to laser beam printers but also to optical information processing devices such as optical discs and optical communications.

〔Effect of the invention〕 As described above, the semiconductor laser device according to the present invention is provided.

In a semiconductor laser device consisting of a plurality of semiconductor laser chips, at least one pair of laser chips is separately fixed to two surfaces facing each other with a space between them, so that the semiconductor laser has a plurality of different characteristics. This makes it possible to stack chips, and furthermore, it is possible to narrow the light emitting spot spacing between the semiconductor laser chips to 100° or less without causing thermal or electrical interference. This has the effect of improving the functions of semiconductor laser devices and their peripheral devices, that is, optical information processing devices, such as increasing the speed and speed of laser beam printers.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a first embodiment of a semiconductor laser device according to the present invention, in which (a) is a plan view, (b) is a side view, and
The figures are enlarged views of the central part of FIG. 1, in which (a) is a plan view, (b) is a side view, FIG. The figures are explanatory diagrams showing a second embodiment of the invention, FIG. 5 is a diagram showing a third embodiment of the invention, and FIG. 6 is a diagram showing a fourth embodiment of the invention. 1.2.38.39.43.44.59.6o, 101
．． 102...Semiconductor laser chip 5.7.48.49 River electrode surface

Claims (1)

[Claims] 1. In a semiconductor laser device comprising a plurality of semiconductor laser chips, at least one pair of semiconductor laser chips:
A semiconductor laser device characterized in that the semiconductor laser device is separately fixed to two surfaces facing each other with a space between them. 2. A semiconductor laser device comprising a plurality of semiconductor laser chips, characterized in that at least one pair of semiconductor laser chips are arranged such that the electrode surfaces of the semiconductor laser chips are substantially parallel to each other and face each other. Semiconductor laser equipment. 3. The semiconductor laser device as set forth in claim 2, wherein the electrode surfaces arranged to face each other are bonded to each other so that the two semiconductor laser chips are integrated.