JPH0448664A - Array semiconductor laser edge excitation solid state laser - Google Patents

Abstract

PURPOSE:To acquire a semiconductor laser excitation solid state laser which produces solid state laser output light effectively by providing an optical coupler which consists of a lens array and a second lens used as a focusing lens. CONSTITUTION:An Nd:YAG laser is used as a solid state laser element 4. Diachronic coating is performed for one edge face and a resonator is formed of the face as an excitation surface and of an output mirror 5. The used array semiconductor laser 1 is composed of an array which is formed by wiring 20 active layer stripes 7 of 100mum width at 500mum interval. A condenser lens array 2 is composed of 20 distribution factor lenses of 500mum width and condenses and collimates each projection light from 20 stripes. Then, 20 laser beams are focused by a second lens 3 and superposed at one place for end excitation of a solid state laser element 4 which consists of Nd:YAG rod. A highly efficient solid state laser of good beam quality and high output can be realized in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a semiconductor laser pumped solid-state laser that optically couples the output of a semiconductor laser as an edge light source with high efficiency and optically pumps a solid-state laser element.

[Prior Art] Solid-state lasers using semiconductor lasers as excitation light sources are attracting attention because of their high efficiency, long life, and miniaturization. In a semiconductor laser-pumped solid-state laser, the end-pumping method (for example, see Japanese Patent Application Laid-open No. 58-52889), in which the solid-state laser is optically pumped from the optical axis direction, effectively uses the excitation space by the semiconductor laser output light as the spatial mote of the solid-state laser's oscillation. By matching, highly efficient single basic tank moat oscillation can be realized.

[Problems to be Solved by the Invention] Since a semiconductor laser has a large beam divergence angle, it is necessary to bring a condensing system close to the semiconductor laser to condense the light, and condensing the oscillated light is not easy. In order to increase the output of a semiconductor laser-excited solid-state laser, it is necessary to increase the output of the excitation semiconductor laser. Semiconductor lasers emit laser light from a striped active layer, but a single striped laser has a limit to its output, and in order to obtain higher output, it is necessary to form an array of multiple stripes. .

When trying to use such an array semiconductor laser as an excitation light source, the width of the array is about 1 cm, so
Since it is impossible to narrow down multiple beams into a single spot using a normal lens system, it is not possible to adopt an end-face excitation method with good excitation efficiency, and it can only be applied to a side-excitation method (for example, R, Burnham and ,D,
Hays, Opt, Lett, 14°27 (
1989); M, K., Reed, W. J.
Koxlovsky, R.L.

Byer, G. L., Harnagel, and
P, S, Cross, Opt.

Lett, 1:l, 204 (198B), etc.)
.

The present invention was made in view of this situation, and it focuses a large number of beams with a large divergence angle emitted from a multi-striped array semiconductor laser, and excite the spatial mode of the solid-state laser oscillation with the semiconductor laser output light. An object of the present invention is to provide a semiconductor laser-excited solid-state laser that efficiently generates solid-state laser output light so as to match.

[Means for Solving the Problem] In order to achieve the above object, as a means of this invention,
In an array semiconductor laser excitation solid-state laser that focuses the array semiconductor laser output and optically pumps the solid-state laser element, distributed index lenses are arranged corresponding to each stripe of the array semiconductor laser to focus and collimate the array semiconductor laser output. An optical coupler includes a lens array and a second lens used as a focusing lens for collectively condensing each collimated stripe light and superimposing it on one spot to excite the solid-state laser element at the end face. It is something.

[Operation] In the case of an end-pumped solid-state laser, the transverse mode characteristics of a semiconductor laser-pumped solid-state laser are determined by the shape of the optical pumping space within the solid-state laser element. Therefore, in order to obtain a single fundamental transverse mode, it is preferable to make the intensity distribution of the focused excitation light as close to a Gaussian distribution as possible, and to stably create a beam spot of a certain size within the solid-state laser element. .

When used as an optical coupler for a semiconductor laser-pumped solid-state laser, a distributed index lens, which is a cylindrical optical glass body whose refractive index is distributed radially from the central axis to the outer circumferential surface and differs, has a large divergence angle. Semiconductor laser light can be easily focused.

Taking advantage of the fact that laser light from each stripe can be focused using a distributed index lens with such characteristics, the light emitted from each stripe of an array semiconductor laser is focused using a distributed index lens array. High-quality transverse mode light can be obtained by focusing the entire light into a single beam spot using the second lens and exciting the solid-state laser element.

[Example] The present invention will be explained below based on Examples.

FIG. 1 is a schematic diagram of a solid-state laser that focuses array semiconductor laser light and excites a solid-state laser element at its end face. As shown in FIG. 1, an Nd:YAG laser is used as the solid-state laser element 4, and one end face is coated with dichroic
d: YAG laser oscillation wavelength 11064n and high reflection (
HR), high transmittance at semiconductor laser light wavelength of 808nm (AR
)"), and the surface is used as an excitation surface, and the output mirror 5 constitutes a resonator. The array semiconductor laser 1 used
is 7 or 20 active layer stripes with a width of 1100uL or 50
It consists of an array arranged at 0 pm intervals. The condenser lens array 2 is composed of 20 distributed index lenses each having a radiation of 500 uLm, and condenses and collimates each of the light emitted from the 20 stripes. The 20 laser beams are connected to the second lens 3.
Focus and overlap in one place, Nd:YA
The solid-state laser device 4 consisting of G lots is end-face excited.

In the semiconductor laser-excited solid-state laser end-pumped in this manner, high-output oscillation of the Nd:YAG laser fundamental wave (wavelength: 101,064 nm, output: 1.5 W) was obtained by outputting a semiconductor laser of 5 W (wavelength: 808 nm).

[Effect of the invention] As explained above, as the present invention, as an optical coupler,
A semiconductor laser-pumped solid-state laser having the above configuration enables end-face pumping, which has been difficult with conventional array semiconductor lasers, and can realize a high-output solid-state laser with high efficiency and good beam power.

[Brief explanation of drawings]

Figure 1 shows a semiconductor laser-pumped solid-state laser in which light emitted from each stripe of an array semiconductor laser is collected and collimated using a distributed index lens array, focused by a second lens, and superimposed at one location for optical excitation. FIG. In the figure. Array semiconductor laser distributed refractive index lens array lens solid state laser element output mirror output light active layer stripe

Claims (1)

[Claims] In an array semiconductor laser excitation solid-state laser that focuses the array semiconductor laser output and optically pumps the solid-state laser element, distributed index lenses are arranged corresponding to each stripe of the array semiconductor laser to focus and collimate the array semiconductor laser output. Equipped with an optical coupler consisting of a lens array and a second lens used as a focusing lens for collectively condensing each commated stripe light and superimposing them on one spot to excite the solid-state laser element at the end face. An array semiconductor laser edge-pumped solid-state laser characterized by: