JPH01270033A - Laser beam scanner - Google Patents

Abstract

PURPOSE:To control a light convergence position electrically by providing a multiple quantum well structure and a thin film lamination structure consisting of high-refractive index semiconductor thin films and low-refractive index semiconductor thin films which are laminated alternately and vary in period gradually on the surface of a semiconductor substrate adjacently to each other. CONSTITUTION:On the surface of the semiconductor substrate 11, the multi- layered quantum well structure 12 and semiconductor thin film lamination structure 13 are provided adjacently to each other, an electrode 14 is provided on the surface of the multiple quantum well structure 12, and an electrode 15 is provided on the reverse surface of the semiconductor substrate 11. The thin film lamination structure 13 consists of the alternately laminated high-refractive index and low-refractive-index semiconductor thin films, which vary in period gradually in the laminating direction of those thin films. A laser beam L1 is made incident at right angles to the surface of the lamination structure 13, a voltage is applied between the electrodes 14 and 15, and the light convergence point P of projection light L2 projected from the flank of the thin film lamination structure 13 at right angles to the incidence direction is varied with the applied voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a laser beam scanner that can electrically change the focusing position of a laser beam.

4. Prior Art In general, it is known that a waveguide optical device having an uneven grating (chirp gelating) whose period changes slightly gradually has a light focusing function.

As a technical document, American Institute of Telecommunications: Quantum Electronics QE-13, page 298 (April 1977) is known.

As illustrated in FIG. 2, the above-mentioned waveguide type optical device has a thin film guiding waveguide 2 with air as a medium 3 formed on a substrate 1 made of a semiconductor or dielectric, and a thin film guiding waveguide 2 having air as a medium 3 is formed on the substrate 1 made of a semiconductor or dielectric. A grating 4 whose period gradually changes in the Z-axis direction is formed.

In the waveguide type optical device shown in FIG. 2, the laser beam (incident light L+) incident on the thin film optical waveguide 2 from the left direction is
It propagates through the thin film optical waveguide 2 and is emitted to the right (
Outgoing light L2) At this time, if the period of the grating 4 is appropriately selected, the outgoing light L2 is focused at an appropriate distance from the grating 4.

Such a grating (chirp grating) 4
Like a normal grating with a constant period, it is fabricated by two-beam interferometry, and in this case, one beam changes one period, so it is necessary to create an interference pattern through a rod lens.

"Problem to be Solved by the Invention" In the case of the above-mentioned known technology, the focusing position of the laser beam is
It is determined by the change in the period of the grating, but because it is difficult to manufacture a grating whose period changes slightly, it is not possible to reproduce the production time, and from a functional point of view,
It is not possible to continuously change the focusing position of the laser beam.

In view of the above-mentioned problems, the present invention aims to provide a laser beam scanner that can electrically change the focusing position of a laser beam and that can be easily manufactured.

``Means for Solving the Problems J'' In order to achieve the intended purpose, the laser beam scanner according to the present invention has a multi-quantum well structure and a semiconductor thin film laminated structure adjacent to each other on the surface of a semiconductor substrate. The semiconductor thin film stacked structure is composed of high refractive index semiconductor thin films and low refractive index semiconductor thin films stacked alternately, and the period thereof gradually changes in the stacking direction of these Pj films. The present invention is characterized in that electrodes for changing the refractive index of the multiple quantum well structure are provided on the front surface of the multiple quantum well structure and the back surface of the semiconductor substrate, respectively.

rEmbodiment j Hereinafter, embodiments of the laser beam scanner of the present invention will be described with reference to the drawings.

In FIG. 1, on the surface of a semiconductor substrate 11, a multiple quantum well structure (MQW) 12 and a semiconductor thin film laminated structure 13 are provided adjacent to each other, and on the surface of the multiple quantum well structure 12, An electrode 14 is provided, and an electrode 15 is also provided on the back surface of the semiconductor substrate 11.

The multi-quantum well structure 12 is formed through a well-known epitaxial method.

The semiconductor thin film stacked structure 13 is composed of high refractive index semiconductor thin films and low refractive index semiconductor thin films stacked alternately, and the period thereof gradually changes in the stacking direction of these thin films.

This semiconductor thin film stacked structure 13 is also formed through the epitaxial method described above.

The electrodes 14 and 15 are formed by vacuum-depositing, for example, gold on the front surface of the multi-quantum well structure 12 and the back surface of the semiconductor substrate 11.

The semiconductor thin film stacked structure 13 in the present invention functions as chirp gelating for a laser beam due to its stacked structure, and the change in the period of the semiconductor thin film stacked structure 13 is determined depending on the semiconductor film thickness during the epitaxial growth.

As is known, the multi-quantum well structure 12 in the present invention also includes:
By applying an electric field to this, a large change in refractive index can be obtained.

Therefore, in FIG. 1, when the incident light Ll of the laser beam is incident on the semiconductor thin film stacked structure 13 from a direction perpendicular to the surface of the semiconductor thin film stacked structure 13, and at this time, a voltage is applied between the circular electrodes 14 and 15, Semiconductor thin film Il perpendicular to the above light incident direction! Laminated structure] Output light L2 of the laser beam emitted from the side surface of the multi-quantum well structure 3 is focused at 21p corresponding to the change in refractive index of the multi-quantum well structure 12 due to the applied voltage.

Therefore, due to a change in the voltage applied between the circular electrodes 14 and 15, that is, a change in the electric field, the focusing position P of the emitted light L2 changes, and thus laser beam scanning can be performed electrically. .

γ Effects of the Invention j As explained above, the laser beam scanner according to the present invention can change the focusing position of the laser beam by changing the electric field, so desired laser beam scanning can be performed electrically and easily. , Moreover, the semiconductor FI has a multi-quantum well structure and a chirp gelating function.
These main components, such as the J-film stacked structure, can be easily formed with good reproducibility by epitaxial methods.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a layer structure schematically showing an embodiment of a laser beam scanner according to the present invention, and FIG. 2 is an explanatory diagram of a layer structure schematically showing a conventional laser beam focusing device. 11...Semiconductor substrate 12...Multi-quantum well structure 13...Semiconductor thin IA laminated structure 14...
・Electrode 15... Electrode Ll... Incident light L2 of laser beam...
・Output light P of the laser beam...Concentration position of the laser beam Agent Patent attorney Yoshio Saito Figure 1 Figure 2

Claims (1)

[Claims] A multi-quantum well structure and a semiconductor thin film stacked structure are provided adjacent to each other on the surface of a semiconductor substrate, and the semiconductor thin film stacked structure includes a high refractive index semiconductor thin film and a low refractive index semiconductor thin film stacked alternately. and the period gradually changes in the stacking direction of these thin films.
A laser beam scanner characterized in that electrodes for changing the refractive index of the multiple quantum well structure are provided on the front surface of the multiple quantum well structure and the back surface of the semiconductor substrate, respectively.