JPS59101887A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To obtain a high output laser light without damaging the mode of an outputted light by a method wherein a semiconductor laser element having a structure of controlled transverse mode and a semiconductor laser element having a light amplification region of a larger cross-section are arranged in the direction of a light path. CONSTITUTION:When current is injected into the semiconductor element 1 whose transverse mode is controlled, resulting in laser oscillation, the laser light 35 having some radiation angle 36 is radiated. A part of this laser light 35 is injected into the semiconductor element 2. At this time, the injection of suitable current into the semiconductor laser element causes the semiconductor laser element 2 to perform laser oscillation and thus to radiate the laser light 37. Since the area of a part of radiation this laser light 37, i.e., the area of the light emitting region of the semiconductor element 2 is wide, the obtained total output of the laser light 37 becomes large even when the light density of the light emitting region is low to some degree.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to increasing the output of a semiconductor laser device in which the transverse mode is controlled.

In conventional semiconductor laser devices, there are two contradictory problems when trying to obtain high-output laser light. The first problem is that a semiconductor laser device with a controlled transverse mode has a very narrow light emitting region, so during high-output operation, its high light density tends to cause deterioration, especially at the cavity end facets, making it unreliable. There are sexual problems. On the other hand, in a semiconductor laser device with a wide light emitting region, when the laser output is increased, the transverse mode of the laser beam gradually shifts from the zero-order mode to the first-order, second-order, and higher-order modes. This is the second problem.

An object of the present invention is to overcome the above-mentioned problems and provide a structure for a high-power semiconductor laser device in which the transverse mode is controlled. one semiconductor laser element has a structure in which at least a transverse mode is controlled, and the other semiconductor laser element has an optical amplification device having a cross-sectional area larger than at least the transverse mode controlled semiconductor laser element. This is achieved by a semiconductor laser device characterized by having a region. In other words, in order to obtain high-output laser light, the area of the light emitting region is increased by increasing the cross-sectional area of the optical amplification region to prevent deterioration at the end face, and the light density at the resonator end face is increased. Just make sure it doesn't get too high.

As described above, in a semiconductor laser device having a conventional structure, when the area of the light emitting region is increased, higher-order mode oscillation is likely to occur. However, by injecting external light, it is possible to suppress the generation of higher-order modes. The present invention makes full use of this effect to provide a high-power semiconductor laser device with transverse mode control.

According to the present invention, two semiconductor laser elements are arranged in the optical path direction, one semiconductor laser element has a structure in which at least the transverse mode is controlled, and the other semiconductor laser element has at least the above-mentioned lateral mode. A semiconductor laser device characterized in that it has an optical amplification region with a larger cross-sectional area than a mode-controlled semiconductor laser element can be obtained.

Hereinafter, the present invention will be described in detail based on specific examples of embodiments.b FIG. 1 is a diagram showing the basic structure of a semiconductor laser device according to the present invention. That is, it has a structure in which a semiconductor laser confectionery 1 whose transverse mode is controlled and a semiconductor laser element 2 having an optical amplification region wider than the semiconductor laser element 1 are arranged in series in the optical path direction with a groove 3 separating them. Each of the semiconductor laser elements 1 and 2 is arranged between surfaces 9 and 1o and between surfaces 11 and 11, respectively.
12 is configured as a resonator, and electrodes 6 and 7 are attached to each. A current sufficient for laser oscillation is passed between electrodes 6 and 8, and a bias is applied between electrodes 7 and 8 to the extent that laser oscillation will not occur unless light is injected from the outside, but the laser will oscillate if light enters from the outside. I'll keep it.

Note that in the figure, both 4 and 5 indicate the PN junction surface.

FIG. 2 shows the current I-light output P characteristics of the semiconductor laser device when light is injected from the outside. In the figure, the horizontal axis is the flow rate, and the vertical axis is the optical output P.

Furthermore, Pex is the intensity of the injected light from the outside, and P2>P
1>O. That is, the solid line is the case where no light is injected from the outside, and the broken line is the current - light output P characteristic when the light is injected from the outside. From FIG. 2, it can be seen that by biasing the semiconductor laser element to an appropriate current value, the semiconductor laser element oscillates with an intensity corresponding to the intensity of externally injected light.

By the way, in general, in a semiconductor laser device, when the laser light intensity increases, the oscillation mode tends to become unstable and tends to shift to a higher-order mode. However, it is known that the oscillation mode can be stabilized by injecting light from the outside.

FIG. 3 shows the operating state of the semiconductor laser device according to the present invention. In the figure, 1.2 is a semiconductor laser device with a controlled transverse mode and a semiconductor laser device having an optical amplification region wider than the semiconductor laser device, and each semiconductor laser device has an optical amplification region of width 32. Area 31 and width 3
It has four optical amplification regions 33. Now, when a current is injected into the semiconductor laser element 1 whose transverse mode has been controlled and the semiconductor laser element 1 is caused to oscillate, a laser beam 35 having a certain radiation angle 37 is emitted. A part of this laser light 35 is injected into the semiconductor laser element 2. At this time, if an appropriate current is injected into the semiconductor laser element 2, the semiconductor laser element 2 causes laser oscillation and emits a laser beam 37. Since the area of the emission part of this laser beam 37, that is, the area of the light emitting region of the semiconductor laser element 2 is wide, the light density of the light emitting region is low to some extent (-r is also obtained, and the total output of the laser beam 37 is large. .

In the above embodiment, in order to widen the cross-sectional area of the optical amplification region of the semiconductor laser device 2, the width of the optical amplification region was changed to increase the cross-sectional area. It is also possible to widen the cross-sectional area of the optical amplification region by increasing the thickness of the optical amplification region.

In this case, exactly the same effect can be expected.

As described above, according to the present invention, the output light 35 of the semiconductor laser device 1 whose transverse mode is controlled is injected into the semiconductor laser device 2 having an optical amplification region with a wide cross section into which an appropriate current is injected. By doing so, it becomes possible to obtain high-power laser light 37 without damaging the mode of output light 35.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a semiconductor laser device according to the present invention, and FIG.
This figure shows the characteristics when light is injected from the outside into a conventional semiconductor laser device, and FIG. 3 is a diagram showing the operating state of the semiconductor laser device according to the present invention. 1... Semiconductor laser element with controlled transverse mode; 2... Semiconductor laser element having an optical amplification region with a wide cross-sectional area. 2 / Figure 1? Figure ′, Ne I No. 3 (2)

Claims (1)

[Claims] It has a structure in which two semiconductor laser elements are arranged in the optical path direction, one semiconductor laser element has a structure in which at least the transverse mode is controlled, and the other semiconductor laser element has a structure in which at least the transverse mode is controlled. A semiconductor laser device characterized by having an optical amplification region having a larger cross-sectional area than a semiconductor laser element.