JPH04330795A - Semiconductor laser light source - Google Patents

Abstract

PURPOSE:To improve a semiconductor laser light source. CONSTITUTION:A semiconductor laser diode 4, a wavelength converting member 5 made of a nonlinear optical crystal for generating a wavelength converted light by exciting by an output light of the diode 4, and a filter 6 for selectively transmitting only a special wavelength component of the converted light, are provided in the same packages 1, 7. Here, a light incident end face of the member 5 is finished in a convexly curved surface to condense the output light of the diode 4 near the end face of the member.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser light source.

0002

2. Description of the Related Art Semiconductor laser light sources are compact and capable of low-voltage operation, and are therefore widely used in optical communications, optical measurement, optical disk devices, and the like. Incidentally, since a semiconductor laser diode is manufactured using a III-V group compound semiconductor or the like, its output light is limited to a long wavelength. Therefore, as a semiconductor laser light source that can obtain short wavelength light such as in the blue region, for example,
No. 89183 is known. In this semiconductor laser light source, a second harmonic generating element (SHG element) having an optical waveguide structure is coupled to the light emitting end face side of the semiconductor laser diode. According to this, the output light of the semiconductor laser diode is converted into light with half the wavelength, and therefore it becomes possible to output laser light with a short wavelength.

0003

However, since the conventional device described above employs an optical waveguide structure, the beam pattern of the output light is not good. In addition, since light other than the second harmonic is output, and the wavelength of the second harmonic itself is broadened corresponding to the wavelength spread of the output light of the semiconductor laser diode, only a specific wavelength (narrow band) is output. Can't get any light. Furthermore, in the above-mentioned conventional technology, even if an output with a shorter wavelength than the output light of the semiconductor laser diode can be obtained, an output light with a longer wavelength cannot be obtained.

The present invention has been made in view of the drawbacks of the prior art, and uses a laser with a short wavelength or long wavelength compared to the output wavelength of a semiconductor laser diode, a good beam pattern, and a narrow band. An object of the present invention is to provide a semiconductor laser light source that can obtain output.

[0005]

[Means for Solving the Problems] A semiconductor laser light source according to the present invention includes a semiconductor laser diode and a wavelength conversion member made of a nonlinear optical crystal that is excited by the output light to generate wavelength-converted light in the same package. and a filter that selectively transmits only a specific wavelength component of the wavelength-converted light. Here, the light incident end face of the wavelength converting member may be finished into a convex curved surface so that the output light of the semiconductor laser diode is focused near the light emitting end face of the wavelength converting member.

[0006]

[Operation] According to the structure of the present invention, when the output light of the semiconductor laser diode is incident on the wavelength conversion member, second harmonic generation or optical parametric oscillation occurs in the nonlinear optical crystal, and short wavelength or long wavelength light is generated. is converted to Then, by passing through the filter, only the specific wavelength light is selectively output.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a partially broken perspective view showing the structure of a semiconductor laser light source according to an embodiment. As shown in the figure, lead terminals 2 extend on the back surface of the base plate 1.
A substrate 3 is fixed to the front surface. A semiconductor laser diode 4, a nonlinear optical crystal 5, and a wavelength selection filter 6 are sequentially arranged and fixed on the upper surface of the substrate 3, and these are covered with a cap 7 fixed to the base plate 1. A light output window 8 is fixed to the front surface of the cap 7. The electrode of the semiconductor laser diode 4 is connected to the lead terminal 2 via a lead wire 9.

FIG. 2 shows the structure of the above semiconductor laser light source.
Shown in side view. As shown in the figure, the light incident end face of the nonlinear optical crystal 5, that is, the end face on the semiconductor laser diode 4 side, is finished into a convex curved surface. Therefore, the laser light output from the active layer 41 of the semiconductor laser diode 4 is condensed near the light emitting end face of the nonlinear optical crystal 5. Therefore, the effective length of wavelength conversion becomes longer, and the conversion efficiency improves. Then, the light from the light emitting end face passes through the wavelength selection filter 6 and is converted into narrow band short wavelength light.

FIG. 3 shows the structure of a modified example. That is, in FIG. 5A, the nonlinear optical crystal 5 has a convexly curved surface not only on the light incident end face but also on the light emitting end face. Further, in FIG. 2B, the light emitting end face of the nonlinear optical crystal 5 is processed into a concave curved surface. If you do this,
Adjustment of the focal point of the output light of the semiconductor laser diode 4,
Beam pattern shaping can be performed. Also,
The nonlinear optical crystal 5 can also function as a laser medium by mirror-finishing the end face of the nonlinear optical crystal 5 or by providing a suitable mirror to form a resonator structure.

In wavelength conversion, a second harmonic generation process or an optical parametric oscillation process can be applied. When using the second harmonic generation process, the LNO crystal, that is, the nonlinear optical crystal 5 is cut at a specific angle, and the laser light (wavelength input) from the semiconductor laser diode 4 is made incident. Then, light with a wavelength of λ/2 (second harmonic) is generated. For example, if the output wavelength of the semiconductor laser diode 4 is λ
= 850 nm, and a BBO crystal (
When β-BaB2 O4 ) is used, the second harmonic is obtained at a crystal cut angle Θ=27.5 (deg), and its wavelength is 425 nm. The phase matching curve of the second harmonic is as shown in FIG.

When using optical parametric oscillation (OPO), a laser beam of λ=850 nm is used as the excitation light, and an LN crystal (LiNbO3) is used as the nonlinear optical crystal 5.
Use. Then, at Θ=46.1 (deg), signal light=1300 nm and idler light=2456 nm are generated. The phase matching curve of optical parametric oscillation is as shown in FIG.

0012

[Effects of the Invention] As described above, in the present invention, the output light of the semiconductor laser diode is incident on the wavelength conversion member.
Second harmonic generation or optical parametric oscillation occurs in the nonlinear optical crystal and is converted into short or long wavelength light. Then, by passing through the filter, only the specific wavelength light is selectively output. Therefore, it is possible to obtain a laser output with a shorter wavelength or longer wavelength than the output wavelength of the semiconductor laser diode, a good beam pattern, and a narrow band.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a semiconductor laser light source according to an embodiment.

FIG. 2 is a side view of the semiconductor laser light source of FIG. 1;

FIG. 3 is a side view of a modified semiconductor laser light source.

FIG. 4 is a phase matching curve of the second harmonic.

FIG. 5 is a phase matching curve of optical parametric oscillation.

[Explanation of symbols]

1...Base board 2...Lead terminal 3...Substrate 4...Semiconductor laser diode 5...Nonlinear optical crystal 6...Wavelength selection filter 7...Cap 8...Light output window 9...Lead wire 41...Active layer

Claims (2)

[Claims] 1. In the same package, a semiconductor laser diode, a wavelength conversion member made of a nonlinear optical crystal that is excited by the output light of the semiconductor laser diode to generate a wavelength-converted light, and a wavelength-converting member comprising a semiconductor laser diode and a wavelength-converted member comprising a nonlinear optical crystal that is excited by the output light of the semiconductor laser diode to generate a wavelength-converted light; A semiconductor laser light source characterized by being provided with a filter that selectively transmits only wavelength components. 2. The semiconductor laser according to claim 1, wherein the light incident end face of the wavelength converting member is finished with a convex curved surface, and the output light of the semiconductor laser diode is focused near the light emitting end face of the wavelength converting member. -The Light Source.