JPS62268177A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To miniaturize a semiconductor laser device, and to lower the dielectric loss of a wiring by forming a plurality of semiconductor lasers emitting beams in the mutually different directions and a driver circuit driving these semiconductor lasers in a monolithic manner. CONSTITUTION:Sn is diffused to a semi-insulating GaAs substrate 101 as a contact layer, and N-GaAs regions 103 and 106 are shaped, and a thin-film is prepared onto the regions 103, 106 to a shape corresponding to laser structure. Array lasers 102 are prepared and photodetector sections 104 are formed, epitaxial layers are all removed in an FET, a resistor, a capacitor, etc., and a region 105 is shaped through the implantation of S<+> ions, the implantation of Be ions, etc. The photodetectors 104 also control outputs from the lasers as monitors to respective laser and the driver circuit 105 also do so in response to the lasers and the photodetectors at 1:1. Accordingly, a device is miniaturized and the dielectric loss, etc. of a wiring are lowered, and operation at high speed can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a semiconductor laser device in which a plurality of semiconductor lasers are monolithically formed.

[Prior art]

Conventionally, when designing an optical scanning device using a plurality of semiconductor lasers or light emitting diodes (LEDs), as disclosed in JP-A-59-126, for example, the light emitted from the light emitting body is The emission direction is one point P.

The light sources are arranged so that they intersect at the same point, and the scanning spot (not shown) can be scanned with a plurality of scanning spots while maintaining a good image formation state.

FIG. 3 shows a typical conventional example, and is a diagram of the optical system between the light source and the deflector, viewed from a direction perpendicular to the deflection scanning plane. 31a and 31b are semiconductor lasers, and each laser is arranged on the mount 32 so that its light beam generating surface is parallel to the end surface of the mount 32. The end faces 32a and 32b of the mount 32 on which the semiconductor lasers 31a and 31b are provided are the respective lasers 31a.

The center rays ha and hb of the diverging light beam from 31b are set as if they had passed through the same point Po. In other words,
At the position where the semiconductor lasers (31a, 31b) are provided,
When normal lines are drawn to the end faces 32a and 32b, each normal line is P. The end faces 32a and 32b are set such that the end faces 32a and 32b pass through. Furthermore, when viewed from a direction parallel to the deflection scanning plane,
The central ray ha of each semiconductor laser.

P of hb. The position of the semiconductor laser provided on the mount 32 is set so that the position passing through the point is slightly displaced in a direction perpendicular to the deflection scanning plane.

Above P. The point P in a predetermined vicinity of the deflection reflection surface 33 of the deflector is maintained in an optically conjugate relationship by the imaging lens 34.

In this way, in order to arrange multiple semiconductor light emitting devices (for example, semiconductor lasers) so that their respective light emission directions are different, they must be aligned on the mount and configured into a hybrid structure, as shown in the example above. I felt the need to. For convenience, the term "array laser" will be used below to refer to a plurality of semiconductor light emitting elements, but in principle it also applies to light emitters such as LED arrays.

Furthermore, when using a monolithically formed array laser, it is necessary to install some kind of optical system in front of the array laser. In an example disclosed in Japanese Patent Laid-Open No. 58-211735, a prism is placed in front of an array laser. This is shown in FIG.

FIG. 4 shows a cross section of a prism when a semiconductor array laser has five light emitting parts. 41 is a semiconductor array laser having five light emitting parts (41a, 41b, 41c, 41d, 41e), and 42 is a prism. The central ray ha of the luminous flux from the light emitting part 41a is on the inclined surface 42.
It is as if P is refracted by a. It is bent as if it had passed through. Same < The central ray hb from 41b passes through the inclined surface 42b, the central ray hd from 41d passes through the inclined surface 42d, and the central ray he from 41e passes through the inclined surface 42.
e, respectively, as if P.

It is bent as if it had passed through. Note that the central ray hc from 41c passes through the plane 42c perpendicularly, and P is on the extension line of this central ray hc. exists.

In this way, an inclined plane with a defined inclination angle is provided corresponding to each light emitting section, and the center ray of each luminous flux after exiting the prism 42 is as if P. Its direction is controlled as if it were emitted from a source. This P. As described above, is maintained conjugate to a desired position P (not shown) near the deflection/reflection surface via the optical system.

Problems in this case include the precision and method of microfabrication of the prism 42, the alignment and bonding method between the prism 42 and the array laser 41, and the smaller the pitch of the array laser, the more difficult it becomes. In fact, it is almost impossible if the thickness is less than 100 μm.

On the other hand, FIG. 5 shows an optical system, that is, a relay optical system 53, which is intended to have a similar effect.
This is an example in which a relay optical system 53 is interposed between a collimator lens 52 and a cylindrical lens 55 that collimate and image the light emitted from 1b, and an image is formed on a polygon surface 54, and the image is scanned in a good image formation state. The image is formed on a surface (not shown). The problem in this case is the optical path length, and the relay system itself is approximately 20 cm long.

On the other hand, in order to solve the above-mentioned problems, the present applicant has proposed a method in which a plurality of semiconductor lasers are monolithically formed, and each semiconductor laser is formed monolithically. A semiconductor device has already been proposed in which the laser beams are emitted in different directions.

[Summary of the invention]

The object of the present invention is to provide a semiconductor laser device that can be easily manufactured and that can be combined with a lens etc. to form an optical system with a short optical path length. This will further improve performance.

The above object of the present invention is achieved by a semiconductor laser device in which a plurality of semiconductor lasers that emit light in mutually different directions and a driver circuit that drives each of these semiconductor lasers are monolithically formed.

Note that the expression "the directions of light emitted from each laser are different" used in the following description does not mean that there are no sets of lasers that emit light in the same direction, but in a broad sense, there is one set of lasers that emit light in different directions. This means that there are more than one set.

When using a semiconductor laser, power control, wavelength control, etc. are important. As devices become more multifunctional, these control circuits occupy a larger area within the device.

The features of the present invention are that the above-mentioned oblique emission is realized by integrating transistors, photodetectors, etc. on the same substrate in the array laser, thereby realizing the above-mentioned power control, etc., and at the same time miniaturizing the driver device and reducing the Reduction of Loss [Example] Examples of the present invention will be shown below with the help of figures.

FIGS. 2(b) and 2(c) illustrate the present invention.

A power controller as shown in Figure 2(a)
2(b) and 2(c) show that the circuit including 1 was formed on the same substrate as the oblique emitting laser.

The embodiment of FIG. 2(b) is shown. The substrate 101 is a semi-insulating GaAs substrate. In order to form a laser structure and a PD structure on this substrate, Sn is first diffused into the substrate 101 as a contact layer, as shown in 103 and 106. Form an n-GaAs region. On top of this, a thin film is formed in a shape corresponding to the laser structure.

For example, 0.5 μm1 of 5idoped GaAs
Furthermore, S i d o p e d which becomes a cladding layer
A l O, 3G a O, 7A s is further 1.
5 μm active layer and
0.1 μm of oped GaAs and 1 layer of Be doped Alo3Gao7As as a cladding layer on top of it.
．． 5 .mu.m thick, and then Be-doped GaAs is formed to 0.5 .mu.m thick. This is formed by laser pattern formation using normal photoresolution and RIBE method.
The array laser shown in 104 is fabricated, and the photodetector portion shown in 104 is formed. In this way, the laser section is formed.

Furthermore, FETs, resistors, capacitors, etc. are formed by ion implantation of Di, Be ion implantation, etc. after removing all the above-mentioned layers. This area is shown at 105.

In this example, there are three laser arrays, but the photodetector 104 also monitors each laser, and the driver circuit 105 also controls the laser output in one-to-one correspondence with the laser and photodetector. .

FIG. 2(c) is an example of FIG. 2(a) formed vertically. A laser 111 and a photodetector 113 are formed on semi-insulating GaAs 110 by the method described above. 112 and 115 are n by diffusing Sn.
This is the mark of creating an area. Further, 114 is also formed by the same method as in FIG. 2(b). However, depending on the method of forming the driver, it is formed vertically.

In this example, the size of Figure 2(b) is 1.5 mm
Xlmm.

The size of FIG. 2(C) was 1 mm x 1.5 mm.

In the present invention, a laser is created by forming an n shadow region by diffusing Sn, but this may also be formed by Zn and becoming a p shadow region. However, in this case, P and n of the grown film should be reversed. Finally, wiring such as An evaporation is performed to form an integrated circuit.

Here, an example of the configuration of the oblique emission section is shown in FIG.

In the figure, 11-15 indicate individual semiconductor lasers, lla
15a corresponds to a current injection region, ie, a light emitting region, in each of the semiconductor lasers 11 to 15. And this injection area 11
Extension line of a-15a (hereinafter referred to as resonance direction) l
Normal line 18 erected to lb~15b and resonance surfaces 16 and 17
The angles formed with are φa, φb, and φC2φd, respectively.

It is formed so that it becomes φe.

Note that the resonance planes 16 and 17 are parallel because the cleavage planes of a crystal (for example, (AAs)) used as a substrate are usually used, but the parallelism may be slightly different due to dry etching. In such a case, consider the resonance surface 16 on the laser emission front side as a reference.

When the light resonated at the resonant surfaces 16 and 17 is emitted from the resonant surface 16 as a laser beam, it is bent according to Snell's law. In the figure, 11c=15c indicates the light emission direction.

Here, if the angle between an arbitrary light emission direction and the normal line 18, that is, the emission angle is θ, then n/n0=sinθ/sin
The relationship φ holds true. For example, considering the case where the light is emitted from a GaAs crystal, n (the refractive index of the crystal) is approximately 3.5, no.
(The refractive index of air) is about 1, so if φ is chosen to be 1 degree, the laser beam will be emitted at an angle of about 3.5 degrees with respect to the normal 18.

In the embodiment shown in FIG. 1, φa, φb2φC2φd.

φe +1.0 degrees, +0.5 degrees, 0.0 degrees, respectively.
By setting -0.5 degrees and -1.0 degrees,
Output angle θa.

θb, θC1θd, θe are +3.5 degrees and +1.75 respectively
Every time.

We were able to create array lasers with angles of 0.0 degrees, -1.75 degrees, and -3.5 degrees.

The exit angle in FIGS. 2(b) and (C) is +1.75 degrees.

00 degrees and -1.75 degrees. However, if the angle φ is too large, the angle of incidence on the resonant surface will increase and the reflectance will decrease, so it is appropriate that the angle φ be within ±15 degrees. In particular, when φ is ±3 degrees (the rise in the oscillation threshold current is only about 10 to 20% up to approximately 10%), it is easy to drive.Moreover, it is possible to change the light emission angle θ to about ±10 degrees. be.

Furthermore, it is generally convenient for device design to use constant values for the distance between lasers and the deviation θ in the light emission direction. However, it is not necessarily necessary to take a constant value.

In addition, the material of the semiconductor laser is GaAs-Aj2GaA
In addition to s-based, InP/InGaAs-based, AfGalnP
Needless to say, the same applies to materials such as systems.

Furthermore, as shown in FIGS. 6 and 7, it is also possible to form the output end face perpendicular to the implantation region by dry etching. It is easy to replace the laser section shown in FIGS. 2(b) and 2(C) with the device shown in FIG. 6 or 7.

〔Effect of the invention〕

As explained above, each component of the present invention includes:
By integrating the driver, devices such as laser drivers can be made smaller, and the dielectric loss of wiring can be reduced, making it possible to achieve high-speed operation.

[Brief explanation of drawings]

FIG. 1 is a plan view of a semiconductor laser used in the present invention, FIGS. 2(a), 2(b), and 2(C) are schematic diagrams explaining the present invention in detail, and FIG. Fig. 4 shows a conventional example in which an array laser with a constant emission direction and a prism are made into rigid bodies and have different emission directions. Fig. 5 shows an array laser with a fixed emission direction in an optical configuration. Figure 6 shows a conventional example when attempting to correct using a system.
7 and 7 are plan views showing a modification of the present invention. 11-15... Semiconductor laser, 16.17...
...Resonance surface.

Claims (1)

[Claims] (1) A semiconductor laser device in which a plurality of semiconductor lasers that emit light in different directions and a driver circuit that drives each of these semiconductor lasers are monolithically formed.