JPS60182790A - Semiconductor laser array device - Google Patents

Abstract

PURPOSE:To perform laser oscillation of stable mode at high output by outputting laser beams synchronized at 0 deg. phase from alternate stripes by a method wherein the difference in phase between each laser action part of the titled device is selected by a resonator and a reflectance. CONSTITUTION:A plurality of stripe current paths are disposed in an array in a polycrystalline layer for laser action, and laser action parts 1, 2, 3... are arranged in parallel. Distributed Bragg reflectors 2', 4'... are formed at one ends of the resonators of action parts 2, 4... at the even-numbered stages of the action parts 1, 2, 3... of this parallel arrangement in a holographical manner. On the other hand, resonance surfaces by reactive ion etching are formed at one ends of the action parts 1, 3... at the odd-numbered stages, and then coated with a dielectric permeable film 001. The oscillation threshold value of resonance surfaces is decreased by coating the other resonance surfaces of the action parts 1, 2, 3... at the even- and odd-numbered stages with a multilayer film 002 of high reflactance made of Al2O3 and SiO2. Then, laser oscillation of stable mode is performed at high output by 180 deg.-inversion of the distribution of electric intensity of the action parts 1, 3... and 2', 4'....

Description

Detailed Description of the Invention Technical Field> The present invention relates to the structure of a semiconductor laser array, and in particular, the present invention relates to the structure of a semiconductor laser array, and in particular, the electric field between adjacent laser operating sections is provided with a phase difference of 90 degrees, so that the laser beams of every other laser operating section are This invention relates to a root-body phase-locked laser array device that is phase-locked to zero degrees.

<Prior Art> Semiconductor laser devices have the most suitable conditions as information processing light sources for optical disk information processing devices, laser printers, etc., and their practical use is being promoted.

With the gradual increase in the amount of information to be processed, there has been a demand for faster processing speed, and for this reason semiconductor laser devices have been designed to achieve as high output as possible within the range of stable operating characteristics. Technological development is progressing rapidly. However, at present, in consideration of practicality, only a device with a maximum output of 50 mWi degrees can be obtained with a semi-3Hp laser compound having a single active region.

On the other hand, attempts have been made to create a single-phase, high-output laser device by arranging a large number of semiconductor laser elements in parallel and optically phase-coupling them.

This is commonly referred to as a phase-locked laser array. However, conventionally, in gain-guided laser arrays, due to the increase in loss due to the decrease in gain in the coupling region located between individual laser operating sections, the electric field phase difference between matched laser operating sections is 180 degrees. As a result, the far-field image has many peaks as shown in FIG. 1, which is inconvenient in terms of application. In order to improve this problem, it is possible to use a refractive index guided laser array.

Heuret Paracard Glue, E, Ackle
y, etc. IJ-key mode, proposes to form an array of implantable laser elements (Appl, Ph.
ys, Let Eers.

39(1) 1. July 1981 P27)o
However, although the laser array with this structure has a high coupling efficiency between each laser operating section, it is essentially a leaky mode, so the far-field pattern has two peaks.

RCA Laboratory Nori, Botez et al. have developed CSP-L QC (Channeled QC) with channels formed on the substrate.
-5ubstrate large-optiral-c
avity) Advocates L Noza Yuko (docu)
ment of 100Cl98B '29B5-2)
.

Since this utilizes the equivalent refractive index distribution formed by bonding with the CaAs substrate, the region between each laser operating section has a large absorption coefficient, and if this is made small, there will be no refractive index difference. It has a contradictory structure.

Therefore, it is not easy to reduce the phase difference between each laser operating section to zero degrees.

In addition to the above, ridge-type laser arrays have been proposed by Hewlett-Paracard Co., Ltd., E., Ackley, and others (
Appl, Phys, Letters, 42(2), 1
5 January 1983, P152). However, in this structure, due to increased absorption by the electrodes in the region between each laser operating section, the phases between the laser operating sections are shifted by 180 degrees.

<Object of the Invention> In view of the above-mentioned problems, the present invention allows the phase difference between each laser operating part to be selected by the reflectance of the resonant surface, and laser beams emitted from every other stripe with zero degree phase synchronization. The overall purpose of the present invention is to provide a new and useful semiconductor laser array device that can output .

<Embodiment> FIGS. 2A and 2B are a plan view and an electric field intensity distribution diagram of a semiconductor laser array device showing an embodiment of the present invention.

G is grown on a GaAs substrate by the well-known liquid phase epitaxial growth method.
a1-XAtXAs cladding layer, Gal, AtyAs
Active layer, GaI XAIXAS cladding layer (x>y)
, GaAs cap layers are sequentially grown to form a double heterojunction type multilayer crystal for laser operation. Electrodes for carrier injection are provided on the cap layer and the back surface of the GaAs substrate, and a plurality of stripe-shaped current paths are arranged in parallel in the multilayer crystal layer for laser operation, so that the laser operation section is arranged in parallel as shown in Figure 2 (A). Place it in A striped current path (for example, width of about 4/IPn) can be formed using an electrode stripe structure in which the current path area is limited by interposing an insulating film, a planar stripe structure in which the current path is opened by diffusing impurities, or a GaAs substrate. Formed by an internal stripe structure, etc., in which a current blocking layer is interposed between multilayer crystal layers for laser operation to limit the current path area.
A large number of these are arranged in parallel at a constant pitch (for example, about 8 μm) to produce a one-chip laser array.

Laser operating section arranged in parallel 1.2.3.4. . . , even-numbered laser operating units 2, 4 . A distributed Bragg reflector 2C4<-- is holographically formed at one end of the resonator. Distributed black reflector 2.
/ 4. /... is a waveguide layer composed of a diffraction grating formed following the active layer, and the laser action is performed in this part.On the other hand, the odd-numbered laser operation parts 1.3. 5
．． One end of .
1. Even-numbered and odd-numbered laser operating units 1.2, 3, 4, 5. Since the other resonance surface of ... lowers the oscillation threshold, AI! 203 and S
It is coated with a multilayer film 002 of high reflectivity consisting of i02.

In the semiconductor laser array device having the above structure, the odd-numbered laser operating parts 1, 3, and
5... electric field strength distribution (01,03,05,-・°
) and even-numbered laser operating units 2, 4 . The electric field strength distribution (02, 04, . . .) is reversed by 180 degrees.

Laser operation part 2.4. Since no laser light is emitted from ..., the output laser light is from the second
As shown in Figure CB), the phase is synchronized at zero degree. Figure 3) is a characteristic diagram showing the optical output-current characteristics and far field of the semiconductor laser array device with the above structure.
One sharp far-field image was obtained up to 9 mW.

<Effects of the Invention> As described in detail above, according to the present invention, laser beams phase-locked at zero degrees are output from every other laser operating section, and laser oscillation in a stable mode with high output can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a far-field image of a gain rod e-type laser array. FIG. 2(A) ([3) is a plan view and electric field intensity distribution diagram of a semiconductor laser array device showing one embodiment of the present invention.0 FIG. 3(A) CB) U Semiconductor laser shown in FIG. FIG. 2 is an explanatory diagram illustrating the optical output-current characteristics and far-field image of the array device. 1.2, 3, 4.5. ...Laser operating part, 2', 4'
...distributed Bragg reflector. Agent Patent Attorney Aihiko Fukushi (2 persons) Tsumeki Figure 1 Figure 3 ¥2

Claims (1)

[Claims] 1. A plurality of laser operating parts are formed in parallel in a multilayer crystal structure for laser oscillation, and a distributed black reflector is provided on every other 0161 plane of the laser operating parts, so that the electric field between the laser operating parts that match 121 is A semiconductor laser array device characterized by providing a degree phase difference.