JPH03276134A - Light emitting device - Google Patents

Abstract

PURPOSE:To output a collimated short-wavelength laser beam and to miniaturize the above device by integrally housing a semiconductor laser, a condenser lens system, a wavelength converting element, and a collimating lens into a package. CONSTITUTION:The semiconductor laser 21 is fixed via a heat sink 12 to a stem 11 of the light emitting device. Focusing lenses 22, 23, the fiber type wavelength converting element 24 and the collimating lens 25 are disposed by aligning the optical axes to the exit optical axis of the semiconductor laser 21 and are respectively adhered and fixed by a VU curing resin, etc., to mounting parts 13, 14, 15 fixed to the stem 11. Further, a cap 10 is so provided as to house the semiconductor laser 21, the lenses 22, 23, the wavelength converting element 24, and the lens 25 therein. The cap 10 is fixed to the stem 11. A window 10a for passing the exit light is bored on the front surface of the cap 10.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a light emitting device that uses a semiconductor laser as a light source and emits laser light with a shorter wavelength than the output laser light of this semiconductor laser.

Prior art and its problems A semiconductor laser that oscillates at short wavelengths in the blue to green range has not yet been realized. Therefore, with the aim of oscillating such short wavelength laser light, attempts have been made to combine a semiconductor laser with a near-infrared oscillation wavelength with a nonlinear optical crystal (KTP, etc.) and generate internal resonance for output. Attempts have been made to combine channel-type guided waveguides (such as L i N b Os). For example, see Umegaki, “Nonlinear optical elements and their materials,” 1 Polymer, Vol. 39, July issue (19
1987) pp 498-501, L, However, the former attempt has the problem of increasing the size of the device, and the latter attempt has the problem that the output light pattern is complex and it is difficult to output collimated light. There is.

OBJECTS OF THE INVENTION The present invention provides a light emitting device that is capable of outputting collimated short wavelength laser light and is miniaturized.

Structure 9 of the Invention Functions and Effects The light emitting device according to the present invention includes a semiconductor laser, a condensing lens system for condensing the emitted light of the semiconductor laser, a laser beam condensed by the condensing lens system enters the laser beam, and the laser beam condensed by the condensing lens system enters. A fiber-type wavelength conversion element that generates a second harmonic with half the wavelength of light.

a collimating lens that collimates the second harmonic emitted from this wavelength conversion element, and the semiconductor laser,
It is characterized by having a package that integrally houses a condensing lens system, a wavelength conversion element, and a collimating lens.

The emitted light from the semiconductor laser is condensed by a condensing lens system and enters the fiber type wavelength conversion element. A second harmonic of the incident laser light is generated by the wavelength conversion element, and this second harmonic is collimated by a collimating lens and emitted.

Even if a semiconductor laser that generates near-infrared or red laser light is used, the wavelength can be reduced to 1/2 by a wavelength conversion element.
Therefore, it is possible to obtain light with wavelengths in the blue to ultraviolet range. And since a fiber type wavelength conversion element is used,
Optical power density is improved and highly efficient short wavelength light can be output.

Furthermore, since the second harmonic output cover turn is symmetrical about the fiber axis, collimated light can be output with a simple optical system. Since collimated light is output, there is no need for an external collimating optical system. Furthermore, since the semiconductor laser, condensing lens system, wavelength conversion element, and collimating lens are integrated into a package, it is possible to downsize and be easy to use.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 shows a light emitting device according to an embodiment of the invention.

A semiconductor laser 21 is fixed to the stem 11 of the light emitting device via a heat sink 12. With the optical axis aligned on the emission optical axis of this semiconductor laser 21, two focusing lenses 22, 23 . Fiber type wavelength conversion element 24
and a collimating lens 25 are arranged, and the stem 11
The mounting members 13, 14, and 15 are fixed to the mounting members 13, 14, and 15, respectively, by adhering them with ultraviolet curing resin or the like. Furthermore, these semiconductor lasers 21. Lens 22.23. A cap 10 is provided to house the wavelength conversion element 24 and the lens 25 therein, and this cap 10 is attached to the stem 1.
It is fixed at 1. A window 10a is opened in the front of the cab 10 to allow the emitted light to pass through. This window 10a
A transparent plate such as glass is provided if necessary. The stem 11 is further provided with an insulated external terminal 16 connected to a terminal of the semiconductor laser 21 .

FIG. 2 is a schematic configuration diagram of the fiber type wavelength conversion element 24, which consists of a central core part 31 and a cladding layer 32 surrounding it. The cladding layer 32 is made of lead glass, for example, and the core part 31 is made of a single crystal of a nonlinear optical material that exhibits a nonlinear optical effect.

Nonlinear optical materials include 2-methyl-4-nitroaniline (MNA), 4-dimethylamino-3-acetamidonitrobenzene (DAN), 2-(α-methylbenzylamino)-5-nitropyridine (MBANP), N
-(5-nitro-2-pyridyl)(S)-prolinol (PNP) and the like can be mentioned. Among these materials, MBANP and PNP have low absorption of blue light and good blue transparency, so they are preferably used in light-emitting devices that emit blue laser light.

In FIG. 1, laser light emitted from a semiconductor laser 21 is focused by focusing lenses 22 and 23, and enters the core portion of a fiber type wavelength conversion element 24. The laser light incident on the fiber-type wavelength conversion element 24 generates a second harmonic (SHG) due to the second-order nonlinear optical effect, and a ring-shaped second harmonic laser light is generated from the cladding part on the output side due to Cerenkov radiation. Emits light. In addition, the wavelength conversion element 2
From the core section 4, the incident fundamental wave is output as is. It is preferable to provide an absorbing portion on the surface of the central portion of the collimating lens 25 so as to absorb the fundamental wave output from the core portion of the laser light emitted from the fiber type wavelength conversion element 24. Thereby, only the second harmonic can be collimated and output by the collimating lens 25. The fundamental wave absorption section may be provided in a transparent plate provided in the window 10a.

An axicon lens is generally used as the collimating lens 25, as shown in FIG.

Same-periodic grating lens (serrated section Fresnel)
A lens) 26 can also be used. In Figure 3,
The other configurations are the same as those shown in FIG.

Next, I will give a specific example.

(1) In the configuration shown in Figure 1, the two oscillation wavelengths are 980 nm,
Semiconductor laser 21 with an output of 40a+W. A wavelength conversion element 24 whose core portion is filled with a single crystal of MNA. When the axicon lens 25 was used, a light emitting device having an overall size of 9 mm in diameter and 6 mm in length was obtained. This light emitting device outputs laser light with a wavelength of 490 rv and an output of 4 IIW.

(2) In the configuration shown in Figure 1, one oscillation wavelength is 860 nta
Semiconductor laser 21. When the wavelength conversion element 24 having a core of a single crystal of MBANP is used, collimated blue laser light with a wavelength of 430 nm can be obtained. The optical output at this time was about 3 mW, and high-power blue laser light was obtained.

(3) In the configuration shown in Figure 3, one oscillation wavelength is 980 nm,
Semiconductor laser 21 with an output of 40 mW. Wavelength conversion element 24 whose core portion is filled with DAN single crystal. When using a Fresnel lens 26, the overall size is 9 in diameter and 6 in length.
An am light emitting device was obtained. This light emitting device has a wavelength of 49
0n, outputs a laser beam with an output of 4a+V.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing a light emitting device according to an embodiment of the invention. FIG. 2 is a perspective view showing the configuration of a fiber type wavelength conversion element. FIG. 3 is a partially cutaway perspective view showing another embodiment of the light emitting device. 10... Cap. 10a... Output light window. 11... Stem. 21... Semiconductor laser. 22, 23... Lens during focusing. 24...Fiber type wavelength conversion element. 25...Collimating lens. that's all

Claims (1)

[Claims] A semiconductor laser, a condensing lens system that condenses the emitted light of this semiconductor laser, a second laser beam having a wavelength of 1/2 of this laser beam, into which the laser beam condensed by this condensing lens system enters.
A fiber-type wavelength conversion element that generates harmonics, a collimating lens that collimates the second harmonics emitted from this wavelength conversion element, and the above semiconductor laser, condensing lens system, wavelength conversion element, and collimating lens are integrated. A light-emitting device comprising a package containing a light emitting device.