JPH07112083B2 - Array semiconductor laser Edge-pumped solid-state laser - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a semiconductor laser pumped solid-state laser that optically couples the output of a semiconductor laser as an end face light source with high efficiency and optically pumps a solid-state laser element.

[Prior Art] A solid-state laser using a semiconductor laser as an excitation light source is attracting attention because it can achieve high efficiency, long life, and miniaturization. In the semiconductor laser pumped solid-state laser, in the end-face pumping method in which the solid-state laser is optically pumped from the optical axis direction (see, for example, Japanese Patent Laid-Open No. 58-52889), the pumping space by the semiconductor laser output light is well matched to the spatial mode of oscillation of the solid-state laser. By doing so, single fundamental transverse mode oscillation can be realized with high efficiency.

[Problems to be Solved by the Invention] Since the semiconductor laser has a large beam divergence angle, it is necessary to focus the focusing system close to the semiconductor laser, and it is not easy to focus the oscillation light. In order to increase the output of a semiconductor laser pumped solid-state laser, it is necessary to increase the output of a semiconductor laser for pumping. A semiconductor laser emits laser light from a stripe-shaped active layer, but a single stripe laser has a limited output, and in order to obtain a higher output, it is necessary to form an array of multiple stripes. .

When such an array semiconductor laser is used as a pumping light source, the width of the array is about 1 cm, so it is impossible to narrow down multiple beams into one spot using a normal lens system. Efficient end-face excitation method could not be adopted and was applicable only to side-excitation method (eg R. Burnham and ADHays, Opt. Lett., 14 , 27
(1989); MKReed, WJKozlovsky, RLByer, GLHarna
gel, and PSCross, Opt. Lett., 13 , 204 (1988) etc.).

The present invention has been made in view of the above situation, and collects a large number of multiple beams with a large divergence angle emitted from a multi-striped array semiconductor laser, and the excitation space by the semiconductor laser output light is set in the spatial mode of oscillation of the solid-state laser. It is an object of the present invention to provide a semiconductor laser pumped solid-state laser capable of efficiently producing solid-state laser output light so as to match the above.

[Means for Solving the Problems] In order to achieve the above object, as means of the present invention,
An array semiconductor laser pumped solid-state laser that collects the array semiconductor laser output and optically pumps the solid-state laser element. In the solid-state laser, a distributed index lens is arranged corresponding to each stripe of the array semiconductor laser, and the array semiconductor laser output is collected and collimated. An optical coupler including a lens array and a second lens that collectively collects the collimated striped lights and superimposes them on one another, and that is used as a focusing lens for exciting the end face of the solid-state laser element. It is a thing.

[Operation] The lateral mode characteristics of the semiconductor laser pumped solid-state laser are determined by the shape of the optical pumping space in the solid-state laser element in the case of the end-face pumping method. For this reason, in order to obtain a single fundamental transverse mode, it is preferable to make the intensity distribution of the narrowed excitation light as close as possible to a Gaussian distribution and to stably form a beam spot of a certain size in the solid-state laser element. .

A semiconductor with a large divergence angle when using a distributed index lens, which is a cylindrical optical glass body with a different refractive index distributed radially from the central axis to the outer peripheral surface, as an optical coupler of a semiconductor laser pumped solid-state laser. Laser light can be easily collected.

By utilizing the fact that the laser light from each stripe can be condensed using the distributed index lens having such characteristics, the light emitted from each stripe of the array semiconductor laser is condensed by the distributed index lens array, High-quality transverse mode light can be obtained by exciting the solid-state laser device by focusing the whole light into one beam spot with the second lens.

[Examples] Hereinafter, the present invention will be described based on Examples.

FIG. 1 is a schematic diagram of a solid-state laser that condenses array semiconductor laser light and pumps a solid-state laser element on an end face. As shown in FIG. 1, Nd: YAG is used as the solid-state laser element 4, and one end face is dichroic coated (Nd: YAG laser oscillation wavelength 1064 nm with high reflection (HR), semiconductor laser light wavelength 808n).
It is highly transmissive (AR) at m, its surface is used as an excitation surface, and the output mirror 5 constitutes a resonator. The array semiconductor laser 1 used has 20 active layer stripes 7 with a width of 100 μm.
It consists of arrays arranged at intervals of 00 μm. The condenser lens array 2 is composed of 20 distributed index lenses each having a width of 500 μm, and condenses and collimates each of the emitted lights from the 20 stripes. The 20 laser beams are focused by the second lens 3 and overlapped at one location to excite the end face excitation of the solid-state laser element 4 made of an Nd: YAG rod.

In the semiconductor laser pumped solid-state laser pumped by the end face in this way, a Nd: YA laser with a 5 W semiconductor laser (wavelength 808 nm) output
High-power oscillation with a G laser fundamental wave (wavelength 1064 nm) output of 1.5 W has been obtained.

[Effects of the Invention] As described above, as an optical coupler according to the present invention,
The semiconductor laser pumped solid-state laser having the above-mentioned configuration enables end facet pumping, which was difficult with the conventional array semiconductor laser, and realizes a high-output solid laser with high efficiency and good beam quality.

[Brief description of drawings]

FIG. 1 shows a semiconductor laser pumped solid-state laser in which light emitted from each stripe of an array semiconductor laser is focused by a distributed index lens array, collimated, focused by a second lens, and superposed at one location for photoexcitation. FIG. In the figure. 1 ... Array semiconductor laser 2 ... Distributed refractive index lens array 3 ... Lens 4 ... Solid-state laser element 5 ... Output mirror 6 ... Output light 7 ... Active layer stripe

Claims (1)

[Claims] 1. An array semiconductor laser pumped solid-state laser for collecting an array semiconductor laser output and optically pumping a solid-state laser device, wherein a distributed index lens is arranged corresponding to each stripe of the array semiconductor laser to collect the array semiconductor laser output. A lens array that emits light and collimates, and a second lens that collectively collects and collimates each of the striped light beams and superimposes them on one another to be used as a focusing lens for exciting the end facet of the solid-state laser element. An array semiconductor laser edge-pumped solid-state laser having an optical coupler.