JPS6323383A - Light beam deflection type semiconductor laser - Google Patents

Abstract

PURPOSE:To focus a semiconductor laser light on an arbitrary position by controlling current values by a method wherein an optical waveguide layer region having an energy gap wider than that of the active layer region part of the semiconductor laser is formed on one resonator end side of the semiconductor laser and a striped current injection region is formed in the optical waveguide layer region in the same direction as that of an optical resonator. CONSTITUTION:In a case where a laser oscillation injection current 406 out of a laser oscillation injection current 405 and the laser oscillation injection current 406 is larger in a semiconductor laser part 403 and an optical waveguide part 404, the wave front of the oscillating light is formed in a protruded distribution on the side of larger current. The phase of the central part is delayed by the current non-injection part of the optical waveguide part of an optical waveguide layer and when the oscillating light is emitted from the optical waveguide part, the light has a wave front distribution to focus on an certain point. If the current values of the laser oscillation injection currents 405 and 406 and a laser oscillation infection current 407 are properly set, the focusing point is moved according to the current values. Accordingly, if this luminous flux 411 is focused by a proper optical system, a semiconductor laser capable of scanning the focusing spot right and left can be obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to the structure of an original beam deflection type semiconductor laser that can deflect the direction of an emitted light beam and move the light emitting point of the emitted light beam. It is.

[Conventional technology]

To polarize the direction of the emitted light of a conventional semiconductor laser,
Some systems use rotating reflective mirrors such as polygon mirrors, while others rely on mechanical action such as moving the optical system using servo motors or the like. Or Applied Physics Letters (ApplPhys, Lett, 3
3 (8), 15 (1978)), a semiconductor laser is provided with two separate current injection electrodes,
By controlling each injection current, the position of the peak intensity of the far-field pattern could be deflected.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional technology, in order to deflect the beam by mechanical action, a highly accurate rotation and movement mechanism is required, which is expensive and requires a large headquarters size.
There is a problem that there is a limit to the miniaturization of the product.

In addition, in a semiconductor laser equipped with two separate ¥L flow injection electrodes, the far-field pattern moves, but the light emitting point hardly moves, so when the light is focused by a focusing optical system, The problem is that the light is concentrated at one point, making it unsuitable for the purpose of moving the focal point.

Therefore, the present invention aims to solve these problems.
The purpose of this is to deflect the emitted light of the semiconductor laser by controlling the current, and also move the light emitting point of the deflected beam, which allows the spot focused by the optical system to move on a plane. Our goal is to provide semiconductor lasers with

[Means for solving problems]

In the double beam deflection type semiconductor laser of the present invention, an optical waveguide layer region having a wider energy gap than the active layer region of the semiconductor laser is formed on one cavity end face side of the semiconductor laser having two injection electrodes. Further, the optical waveguide layer region is characterized in that one or more stripe-shaped current injection regions are formed in the same direction as the optical resonator direction.

[Effect]

According to the above-described structure of the present invention, injection currents are independently passed through the two injection electrodes in the semiconductor laser section, and depending on the ratio of the current values, a distribution of injection carrier D degree is generated in the active layer. Since the phase of the light is modulated by the concentration, the wavefront of the stimulated emission light is curved, and the far-field pattern of the emitted beam has a peak at a position shifted from the direction of the resonator. Further, this stimulated emission light is introduced into the optical waveguide section, and carrier injection occurs by a plurality of injection electrodes installed in the optical waveguide, making it possible to further modulate the phase within this optical waveguide. By appropriately selecting these injection current values, the wavefront can be modulated so that the light flux within the waveguide is focused. As a result,
An original beam deflection type semiconductor laser in which the light emitting point can be moved can be realized only by current control.

〔Example〕

FIG. 1 is a main perspective view of a beam deflection type semiconductor laser in an embodiment of the present invention. It consists of a two-electrode semiconductor laser section (101) and an optical waveguide section (102), and the active layer (113) of the semiconductor laser section and the optical waveguide layer (114) of the optical waveguide section are formed on the same plane. Ru. In non-examples, a configuration example using GaAAAs thread material will be described. GaAlAs of the active layer (113) and GaAAAs of the optical waveguide layer (114) have a large A2 composition ratio of (114), and (
115) has a larger energy gap than GaAJlAs. Therefore, the laser oscillation light generated by the active layer hardly undergoes absorption loss by the waveguide layer. The active layer and the waveguide layer have different conductivity types and have a larger A2 composition than the active layer and the waveguide layer.
07) narrows the carrier and performs confinement,
(10B) 1! A (109) blocking layer is provided after the GaAs contact layer with the pole. This blocking layer is formed of an insulating layer or a GaAs layer having a conductivity type different from that of the contact layer (108). (1
The blocking layer in step 09) is etched into two stripes in the semiconductor laser section by a photolithography process, and etched so as to remain in a stripe shape in the optical waveguide section. Three separate electrical holes (111), (112), and (110) are formed on the two stripes of the semiconductor laser section and the stripe of the optical waveguide layer, and a cladding (107) is formed between 711 of the semiconductor laser section. Perform etching on top. For the three electrodes, independently (116
), (117), and (115) are made to flow.

Figure 2 is a cross-sectional view of people in the first ward. (209),
When carriers are injected from the (210) electrode at different aK values, a carrier concentration distribution occurs in the direction parallel to the junction plane in the active layer. occurs.

Therefore, the laser oscillation light has a phase delay on the t-pole side where the current value is small, and before entering the waveguide, a light intensity distribution with a peak in a direction different from the cavity direction occurs in the far-field image. There is.

FIG. 3 is a sectional view taken along line B in FIG. (309)
A current is injected into the waveguide Ji (505) by one pole, but a distribution occurs in the injected current due to the blocking layer (308). (308), the implantation amount is small, and the other regions have a large implantation amount, so the refractive index is large in the center of the waveguide layer, and the refractive index distribution with a small refractive index in other areas is inside the waveguide layer. Occur. Therefore, the oscillated light from the semiconductor laser section is further subjected to phase modulation in this optical waveguide layer. In Figure 4,
An overview of optical beam deflection will be explained. (403) is a semiconductor laser part, (404) is an optical waveguide part, and is a schematic diagram seen from the top. When the laser oscillation injection currents of (405) and (406) are larger in (406), the wavefront of the oscillated light has a distribution that is convex on the (406) side as shown in the figure. The phase of the central part is delayed by the current non-injection part (408) of the optical waveguide layer, and when the light exits the optical waveguide part, it has a wavefront distribution that focuses on a certain point. If the current values of (405), (405), and (407) are set appropriately, the focal point of (410) becomes (4j3
), it moves according to the current value. Therefore, this light beam (411) is focused by an appropriate optical system)1
, it becomes a semiconductor laser that can scan the focused spot left and right.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to focus the light point of the semiconductor laser at an arbitrary position by controlling the current value, so it is possible to read, write, etc. on an information recording device such as a laser disk. When performing tracking correction, there is no need to worry about mechanically operating the optical system, etc., and this has the effect that it is suitable for making the device smaller, lighter, and faster. Furthermore, when writing with a laser beam printer, etc., there is no need for an optical polarization device such as a polygon mirror, so the optical system can be shortened, which is effective in downsizing the laser beam printer.

[Brief explanation of the drawing]

FIG. 1 is a main perspective view showing an embodiment of the original beam deflection type laser of the present invention. FIG. 2 is a sectional view of the semiconductor laser section taken along section A in FIG. 1. FIG. FIG. 3C is a sectional view of the optical waveguide taken along the B section of FIG. FIG. 4 is a configuration diagram showing beam deflection of the original beam deflection type laser of the present invention. (101), (403)... Semiconductor laser section (
102), (404)... Optical waveguide (103)
, (201), (301)...Lower electrode (104), (202), (302)...Substrate (105), (203), (303)...・Buffer layer (106), (204), (304)...Lower cladding layer (115), (205)...Active layer (1'14)
), (305)... Optical waveguide layer (107),
(2(36), (306)°°・Pa・Upper cladding layer (108), (geo7), (3o7)...Contact layer (109), (208), (30B)... ...Blocking layer (111), (112), (209), (210)...
... Semiconductor laser current injection electrode (110), (30
9)... Optical waveguide current injection electrodes (115), (407)... Optical waveguide injection current (111), (112), (405), (406)...
... Semiconductor laser injection current (4M), (402)
... Semiconductor laser current injection region (40B) ... - Optical waveguide non-current injection region (409)
...Four-wave light wavefront (410) ... Focus point (411) ... Luminous flux (412) ... Far-field image (413) ... ... More than movement of the focal point Applicant Seiko Epson Co., Ltd. Agent Mogami Patent Attorney (1 other person) $Douzu

Claims (2)

[Claims] (1) In a light beam deflection type semiconductor laser having two active layer current injection electrodes that are adjacent to each other and separated and independent, one resonator end face side of the semiconductor laser has an active region that is A semiconductor wave layer region having a wide energy gap is formed, and one or more stripe-shaped current injection regions are formed in the optical waveguide layer region in the same direction as the optical resonance direction. Optical beam deflection type semiconductor laser. (2) The two active layer injection electrodes are an insulating layer or
The light beam deflection type semiconductor laser according to claim 1, characterized in that the light beam deflection type semiconductor laser is formed separately and independently by semiconductor layers of different conductivity types.