JPH0653603A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To obtain a semiconductor laser device which does not generate noise by providing an external wall having a down-grade ahead under a main outgoing beam, and preventing the return light from penetrating into an optical component. CONSTITUTION:This device is provided with a photodetector 7, which is placed on the lead 1 having a positioning means, a semiconductor laser element 12, which is placed on the photodetector 7 or on the lead 1 in front of it and is provided to emit a main outgoing beam 13, and an insulating frame 21, which is formed around the lead 1. And, the insulating 21 has an inclined external wall 22 with a down-grade ahead under the main outgoing beam of the semiconductor laser element 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser device which does not generate noise.

[0002]

2. Description of the Related Art In recent years, many improvements have been made to semiconductor laser devices.
A semiconductor laser device filed in No. 138696 is shown in FIG. In this figure, the light receiving element 32 is mounted on the lead 31, and the semiconductor laser element 33 is mounted thereon. A transparent resin 35 covers the rear surface of the semiconductor laser element 33 and the P-type diffusion region 34 of the light receiving element 32. The other lead 36 is provided separately from the lead 31. A thin metal wire 37 is provided between the semiconductor laser element 33 and the other lead 36.
Is wired. An insulating frame 38 is provided so as to integrally hold the lead 31 and the other lead 36. This semiconductor laser device is fixed to a support 39, and an optical component 40 is fixed thereon.

[0003]

In the above-described semiconductor laser device, however, after the main emission light 41 enters the optical component 40 composed of a diffraction grating or the like, a part thereof is reflected by the optical component 40 and returns light. It becomes 42 and returns to the semiconductor laser element 33 again. Then, the return light 42 is reflected by the end surface of the semiconductor laser element 33, enters the optical component 40 again, and interferes with the main emission light 41, so that noise is generated. Therefore, the present invention has been made in view of the above-mentioned conventional drawbacks, and provides a semiconductor laser device which does not generate noise by preventing return light from entering an optical component.

[0004]

In order to solve the above-mentioned problems, the present invention mounts a light receiving element mounted on a lead having a positioning means, and a light receiving element mounted on or in front of the light receiving element. Further, a semiconductor laser element provided so as to emit the main emitted light forward and an insulating frame formed around the lead are provided. Then, the insulating frame is provided so as to have an outer wall that is inclined downward in the forward direction under the main emitted light of the semiconductor laser device.

[0005]

According to the present invention, as described above, the outer wall of the insulating frame is provided below the main emitted light of the semiconductor laser element and is inclined forward with a downward slope. Therefore, the main emitted light of the semiconductor laser device is reflected by the optical component, and the return light thereof is reflected upward by the inclined outer wall, so that it does not re-enter the optical component.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 is a side sectional view of a semiconductor laser device according to this embodiment, and FIG. 2 is a plan sectional view of the semiconductor laser device. In these figures, the lead 1 is made of a metal material such as copper having a thickness of 0.2 to 1.0 mm and is composed of a rectangular portion 2, a notch portion 3 and a terminal portion 4. The lead 1 has a positioning means 6 such as a V-shaped groove formed on the end face 5. In addition, the positioning means 6 may be a U-shaped groove, a concave portion having a substantially U-shaped cross section, or a convex portion having a V-shaped, U-shaped or substantially U-shaped cross section.

The light-receiving element 7 is, for example, a silicon crystal having a P-I-N structure provided with front electrodes 8 and 9 and a back electrode 10. The surface electrode 9 is formed in ohmic contact with the light receiving surface 11 formed of a P type diffusion region. The light receiving element 7 is fixed onto the lead 1 via a conductive adhesive such as silver paste.

The semiconductor laser device 12 is made of, for example, a GaAlAs light emitting layer composed of an active layer and a clad layer sandwiching the active layer. Both ends of the semiconductor laser element 12 are cleaved and a reflective film is formed on the cleaved surface. Semiconductor laser device 1
2 is fixed on the surface electrode 8 of the light receiving element 7 via silver paste or solder so that the main emitted light 13 is emitted forward. The semiconductor laser element 12 is formed so that the reflectance of the reflective film on the rear surface is higher than that on the front surface so that the secondary emission for monitoring is performed rearward. As described above, the optical axis center line 14 of the semiconductor laser element 12 is the light receiving surface 1 of the light receiving element 7.
It is installed so that it is higher than 1.

The other leads 15 and 16 are made of a metal material such as copper, are located in the notch 3 of the lead 1, and extend in the direction opposite to the direction of the main emission light 13 of the semiconductor laser element 12. The thin metal wire 17 and the other thin metal wire 18 are both made of gold or the like, and are configured to connect the semiconductor laser element 12 and the other lead 15 and the surface electrode 9 of the light receiving element 7 and the other lead 16, respectively. Is wired to. The other thin metal wire 19 is wired so as to connect the surface electrode 8 of the light receiving element 7 and the lead 1. The translucent resin 20 is made of, for example, an epoxy resin, and is formed so as to integrally cover the light receiving surface 11 of the light receiving element 7 from the vicinity of the rear surface of the semiconductor laser element 12.

The insulating frame 21 is made of, for example, a polycarbonate resin or an epoxy resin and has a substantially U-shaped plan view so as to expose the vicinity of the main emitted light 13 of the semiconductor laser device 12, and the lead 1 and the other leads 15 are formed. And 16 are formed by transfer molding so as to sandwich the front surface and the back surface. The insulating frame 21 is located below the main emitted light 13 of the semiconductor laser device 12 and has an outer wall 22 inclined forward and downward.
Has been formed. The opening 23 of the insulating frame 21 located in front of the semiconductor laser device 12 has a surface that is inclined so as to expand toward the front. In order to protect the semiconductor laser device 12, the opening 23 is preferably as small as possible. Further, since the main emission light 13 is radiated in a conical shape, it is necessary to prevent it from hitting the conical beam. These two
In order to satisfy one of the two conditions, the opening 23 is formed to have an inclined surface.

The front wall thickness A of the insulating frame 21 is relatively
The thickness is thin, for example, 0.3 mm. This is to prevent the emitted beam of the semiconductor laser device 12 from hitting the opening 23, and to bring the semiconductor laser device 12 and the optical component 24 as close as possible. The side wall thickness B of the insulating frame 21 is relatively thin, for example, 0.6 mm. This is to make the outer shape of the semiconductor device as small as possible. The rear wall thickness C of the insulating frame 21 is relatively large,
For example, it is formed to 1.5 mm. This is to secure the strength by integrally holding the lead 1 and the other leads 15 and 16. By forming the protruding portion D of the insulating frame 21 in front of the light receiving element 7, it is possible to prevent the light receiving element 7 and the semiconductor laser element 12 from being damaged during mounting or packaging. With these components, the semiconductor laser device 25
Is configured.

Then, the semiconductor laser device 25 is fixed to the support 26 so that the projection or the recess formed on the support 26 and the positioning means 6 formed on the end face 5 of the lead 1, that is, the recess or the projection are fitted to each other. Has been done. Optical components 26 such as a diffraction grating, a half mirror, and an objective lens are provided in the direction of the main emitted light 13 of the semiconductor laser element 12. The optical component 24 may be directly fixed to the opening 27 of the support 26.

In the semiconductor laser device 25, after the main emission light 13 enters the optical component 24 composed of a diffraction grating or the like, a part of the light is reflected by the optical component 24 to become the return light 28 and the semiconductor laser device 12 again. Return in the direction of. The return light 28 reflected by the outer wall 22 having a downward slope below the main emitted light 13 travels upward. Therefore return light 2
8 does not enter the optical component 24 again.

Next, a second embodiment in which the temperature rise of the light receiving element is lower than that of the first embodiment will be described with reference to the sectional view of FIG.
The light receiving element 7a is, for example, a silicon-based crystal having a P-I-N structure provided with a front surface electrode 9a and a back surface electrode 10a. The surface electrode 9a is formed in ohmic contact with the light receiving surface 11a formed of a P type diffusion region. The light receiving element 7a is fixed on the lead 1a via a conductive adhesive.

The submount 29 is made of, for example, silicon and provided with a front surface electrode 8a and a back surface electrode (not shown), and is fixed on the lead 1a with a conductive adhesive. The semiconductor laser device 12 is fixed by being alloyed with the surface electrode 8a of the submount 29.
Thus, the semiconductor laser device 12 is mounted on the lead 1a in front of the light receiving device 7a via the submount 29,
The optical axis center line 14 is at a position higher than the light receiving surface 11a and has a main emission surface in the front.

The transparent resin 20a is used for the semiconductor laser device 12
It is formed so as to cover from the vicinity of the rear surface to the light receiving surface 11a. The numbers in FIG. 3 and the same numbers in FIGS. 1 and 2 indicate the same parts. As described above, the semiconductor laser device 12
Since the light receiving element 7a and the light receiving element 7a are placed on the lead 1a,
Due to the temperature rise of the semiconductor laser element 12, the temperature of the light receiving element 7a does not rise so much. Therefore, the light receiving characteristic of the light receiving element 7a (the monitor current value with respect to the amount of received light) is stable, and the monitor current is also stable.

In the semiconductor laser device of this embodiment, the return light 28 is reflected by the outer wall 22a of the insulating frame 21a as in the first embodiment.
Is reflected upward by the optical axis and does not enter the optical component 24.

In addition to the present embodiment, a recess is formed in the lead, a light receiving element is placed on the recess, and the semiconductor laser element is directly placed on the lead in front of it. The center line of the optical axis is the light receiving surface. You may provide so that it may be in a higher position.

[0019]

As described above, according to the present invention, the outer wall of the insulating frame is provided below the main emitted light of the semiconductor laser element and is inclined forward with a downward slope. Therefore, after the main emitted light enters the optical component composed of the diffraction grating and the like, a part of the light is reflected by the optical component to become return light and returns to the semiconductor laser device again. Then, under the main emitted light, the return light reflected by the outer wall that is inclined downward in the forward direction travels upward. Therefore, the returning light does not enter the optical component again. Therefore, since only the main emitted light enters the optical component, a predetermined emitted light can be accurately supplied to the optical component, and noise due to the returning light does not occur.

Further, according to the present invention, the opening of the insulating frame located in front of the semiconductor laser device is formed so as to widen toward the front. Therefore, it is possible to prevent the conical beam of the main emitted light from hitting the opening, and to make the opening small to protect the semiconductor laser device.

Further, according to the present invention, by positioning the positioning means provided on the lead of the semiconductor laser device and the convex portion or the concave portion of the supporting member, the positional deviation of the semiconductor laser device is prevented, and the relationship between the emitted beam and the optical parts. The position can be held accurately.

[Brief description of drawings]

FIG. 1 is a side sectional view of a semiconductor laser according to a first embodiment of the present invention.

FIG. 2 is a plan sectional view of a semiconductor laser according to a first embodiment of the present invention.

FIG. 3 is a side sectional view of a semiconductor laser device according to a second embodiment of the present invention.

FIG. 4 is a side sectional view of a conventional semiconductor laser device.

[Explanation of symbols]

 1, 1a Lead 6 Positioning means 7, 7a Light receiving element 11, 11a Light receiving surface 12 Semiconductor laser element 13 Main emission light 21, 21a Insulating frame 22, 22a Outer wall

Claims (1)

[Claims] 1. A light-receiving element mounted on a lead having positioning means, and a light-receiving element mounted on the light-receiving element or on the lead in front of the light-receiving element so as to emit main emission light to the front. A semiconductor laser element and an insulating frame formed around the lead are provided, and the insulating frame has an outer wall that is inclined downward in a forward direction under the main emission light of the semiconductor laser element. Semiconductor laser device.