JP3327042B2 - Semiconductor laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to optical information processing, optical measurement,
And a semiconductor laser device used in the field of optical communication and the like.

[0002]

2. Description of the Related Art Conventional optical elements and semiconductor laser devices will be described below. FIG. 8 is an exploded perspective view of a conventional optical element and a semiconductor laser device. In FIG.
1 is a semiconductor laser chip, 2 is a heat sink, 3 is a light receiving element for signal detection, 4 is a light receiving element for monitoring, 5 is an optical element, 6 is a stem, 7 is an electrode terminal, 8 is an insulating member, and 9 is a chip mounting portion. is there. Reference numeral 10 denotes a cap, which is usually made of a metal material, but is not necessarily limited to the metal material.

As shown in FIG. 8, a stem 6 has a chip mounting portion 9 and electrode terminals 7 insulated by an insulating member 8.
Are mounted, and the monitor light receiving element 4 is mounted. The semiconductor laser chip 1 is mounted on the chip mounting portion 9 mounted on the stem 6 via the heat sink 2, and the signal detecting light receiving element 3 is further mounted. The semiconductor laser device is obtained by attaching the cap 10 to which the optical element 5 is attached to the stem 6 and surrounding the above-mentioned constituent members.

In a semiconductor laser device having such a structure,
Since the laser light emitted from the semiconductor laser chip 1 spreads radially, there is a problem that a part of the laser light is irregularly reflected on the metal surface inside the cap 10 and is incident on the light receiving element 4 to generate large stray light noise.

In order to solve this problem, an optical element having a structure in which a concave portion for providing a function as a cap to an optical element using a material such as glass, which is transparent to a laser beam, is provided. Semiconductor laser devices equipped with such devices have been developed. One example of the structure is shown in the cross-sectional view of FIG.

This semiconductor laser device has a structure in which an optical element is integrated with a cap, as shown in FIG. That is, the light receiving element 4 for monitoring a laser beam is mounted on the stem 6, the semiconductor laser chip 1 is mounted on the chip mounting portion 9 attached to the stem 6 via the heat sink 2, and the light receiving element for signal detection is provided. 3 has been implemented. Further, an optical element 11 having a concave portion is attached to the stem 6.

[0007]

However, in the above-mentioned conventional structure, the optical element 11 having the concave portion is usually formed with a taper on the inner surface of the concave portion so that the mold can be easily removed after molding. I do. Further, in order to prevent reflection, an anti-reflection coating film is formed on the laser beam passing surface of the optical element 11, but at this time, the thickness of the anti-reflection coating film becomes non-uniform on the inner side surface of the concave portion. A part of the laser beam emitted from the semiconductor laser chip 1 and spread radially reaches the inner surface of the concave portion of the optical element 11 and has a lower reflectance than the reflection by metal, but has a geometrical shape at the inner surface of the concave portion of the optical element 11. And is incident on the light receiving element 3. For this reason, there is a problem that stray light noise cannot be sufficiently reduced.

The present invention solves such a conventional problem,
An object is to provide a semiconductor laser device in which stray light noise is reduced.

[0009]

In order to achieve this object, a semiconductor laser device according to the present invention comprises a frame having a semiconductor laser.
A chip, a light receiving element, and a concave portion on the frame side;
Transparent to the laser light emitted from the semiconductor laser chip
Optical elements made of clear optical materials and molded with molds
A mounted semiconductor laser device, comprising:
The chip and the light receiving element are formed by the recess and the frame.
An optical axis of the laser light, which is provided in an enclosed space.
And at least one of the inner side surfaces of the concave portion
Substantially parallel and the outer surface of the optical element is tapered
It is configured to be shaped.

[0010]

According to this configuration, since the laser light emitted from the semiconductor laser chip is reflected on the inner surface of the concave portion of the optical element in the direction toward the outside of the semiconductor laser device, the light enters the light receiving element and becomes stray light noise. Can be prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical element and a semiconductor laser device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of this embodiment. In FIG. 1, 1 is a semiconductor laser chip, 12 is a silicon substrate for a heat sink, 3 is a light detecting element for signal detection, 4 is a light receiving element for monitoring, 11 is an optical element having a concave portion, 6 is a stem,
9 is a chip mounting portion.

As shown in FIG. 1, in the present embodiment, the optical element 11 having the concave portion has the optical axis substantially coincident with the optical axis of the incident laser light 13, and
3 has a concave portion whose inner surface is substantially parallel to the optical axis. The optical element 11 is mounted on the stem 6, and the optical axis of the laser beam 13 incident from the semiconductor laser chip 1 is substantially parallel to the inner surface of the optical element 11 having the concave part in a space surrounded by the concave part and the stem 6. The semiconductor laser chip 1 is mounted and arranged on the chip mounting portion 9 via the heat sink silicon substrate 12. Further, the light receiving element 3 for signal detection is mounted on the chip mounting section 9 and the light receiving element 4 for monitoring laser light is mounted on the stem 6 to constitute a semiconductor laser device.

In the optical element and the semiconductor laser device configured as described above, the laser light emitted from the semiconductor laser chip 1 spreads radially, and a portion thereof is formed on the inner surface of the concave portion of the optical element 11. Since the light is reflected in the direction toward the outside of the device, the light is prevented from being incident on the light receiving element 3 for signal detection and the light receiving element 4 for monitoring laser light, and stray light noise can be reduced.

Next, an embodiment in which a holographic grating and a diffraction grating are formed on an optical element having a concave portion will be described. FIG. 2 is a sectional view of an optical element having a holographic grating and a diffraction grating formed on an optical element having a concave portion, and a semiconductor laser device.

In the optical element and the semiconductor laser device shown in FIG. 2, a holographic grating 14 and a diffraction grating 15 are formed on an optical element 11 having a concave portion. Note that one of the holographic grating 14 and the diffraction grating 15 may be formed on the optical element 11. Further, a plurality of holographic gratings 14 and a plurality of diffraction gratings 15 may be formed. With such a configuration, functions such as beam splitting and focusing can be realized, and the functions can be easily controlled by the patterns of the holographic grating 14 and the diffraction grating 15.

Next, an embodiment in which the light receiving element is divided into multiple parts will be described. FIG. 3 is a cross-sectional view of a semiconductor laser device in which a light receiving area of a signal detecting light receiving element is divided into a plurality.

In the embodiment shown in FIG. 3, the light receiving area 16 of the signal detecting light receiving element 3 is divided into two or more. With such a configuration, the size, shape, and the like of the spot of the incident laser beam can be detected. The signal detecting light receiving element 3 and the laser light monitoring light receiving element 4
It is sufficient that at least one of them is mounted as necessary, and a plurality of each may be mounted. In the mounted light receiving element, the light receiving area of all the light receiving elements 4 may be multi-divided, or the light receiving area of a part of the light receiving element 4 may be multi-divided. Either one of the holographic grating and the diffraction grating may be formed on the optical element 11 having the concave portion, both may be formed, or a plurality of each may be formed. With such a configuration, beam split,
Functions such as light collection can be realized, and the functions can be easily controlled by the pattern of the holographic grating and the diffraction grating.

Next, an embodiment in which the semiconductor laser chip is a surface emitting laser will be described. FIG. 4 is a sectional view of this embodiment.

In the semiconductor laser device shown in FIG. 4, a monitor light receiving element 4 is formed on a silicon substrate 12 for heat sink, and a surface-emitting type semiconductor laser chip 17 is mounted on the stem 6 via the silicon substrate 12 for heat sink. Have been. With such a configuration, the semiconductor laser chip 17, the light receiving element 4 for monitoring laser light, and the light receiving element 3 for signal detection can be two-dimensionally arranged, so that the assembly can be easily performed. In the present embodiment, the light receiving element 4 for monitoring and the light receiving element 3 for signal detection are formed on the silicon substrate 12 for heat sink. However, a configuration in which a plurality of chips are mounted may be used. The signal detection light-receiving element 3 and the monitoring light-receiving element 4 may have at least one of them mounted as necessary.
In the mounted light receiving element 3, the light receiving areas of all the elements may be divided, or the light receiving areas of some of the elements may be divided. With such a configuration, the size, shape, and the like of the spot of the incident laser beam can be detected. Further, either one of the holographic grating and the diffraction grating may be formed in the optical element 11, or both may be formed. Further, a plurality of each may be formed. With such a configuration, functions such as beam splitting and condensing can be realized, and the functions can be easily controlled by the patterns of the holographic grating and the diffraction grating.

Next, a description will be given of an embodiment having a reflecting mirror for reflecting the laser light emitted from the semiconductor laser chip. FIG. 5 is a sectional view of this embodiment.

In the semiconductor laser device shown in FIG. 5, a light receiving element 4 for monitoring a laser beam, a light receiving element 3 for signal detection, and a reflecting mirror 18 are formed on a silicon substrate 12 for a heat sink. It is mounted on the stem 6 via the silicon substrate 12.

In this embodiment, a laser beam 13 emitted from a semiconductor laser chip 1 is reflected by a reflecting mirror 18 and enters an optical element 11 having a concave portion. By making the inner surface of the concave portion of the optical element 11 having the concave portion substantially parallel to the optical axis of the laser light 13 reflected by the reflecting mirror 18, the emitted laser light 13 is reflected by the inner surface of the concave portion of the optical element 11. Incident on the light receiving element 3 for signal detection.

In such a configuration, when the numerical aperture of the reflecting mirror 18 with respect to the laser beam from the semiconductor laser chip 1 is not sufficiently large, the laser beam having a relatively large light intensity is directly applied to the inner surface of the concave portion of the optical element 11. Since the light is incident, preventing the reflected light from being incident on the light receiving element 4 is very effective in reducing stray light noise. Further, the semiconductor laser chip 1, the light receiving element for monitoring 4, and the light receiving element 3 for signal detection can be two-dimensionally arranged, so that the assembling can be easily performed. In the present embodiment, the light receiving element 4 for monitoring laser light, the light receiving element 3 for signal detection, and the reflecting mirror 18 are formed on a silicon substrate for heat sink, but a configuration in which a plurality of chips are mounted may be used. If necessary, at least one of the signal detection light-receiving element 3 and the laser light monitoring light-receiving element 4 may be mounted, and a plurality of each may be mounted. In the mounted light receiving element 3, the light receiving area of all the elements may be divided, or the light receiving area of some of the elements may be divided.
With this configuration, it is possible to detect the size, shape, and the like of the spot of the incident laser light. Further, only one of the holographic grating and the diffraction grating may be formed in the optical element 11, or both of them may be formed, and furthermore, a plurality of each may be formed. . With such a configuration, functions such as beam splitting and condensing can be realized, and the functions can be easily controlled by the patterns of the holographic grating and the diffraction grating.

Next, an embodiment using a lead frame provided with a frame body made of an insulating material around it will be described. FIG.
(A) is a top view thereof, and FIG. 6 (b) is a sectional view.

In the embodiment shown in FIGS. 6A and 6B, a light receiving element 4 for monitoring a laser beam and a light receiving element 3 for detecting a signal are formed on the main surface of a silicon substrate 12 for a heat sink. A surface-emitting type semiconductor laser chip 1 is mounted on a chip mounting portion of a lead frame 20 provided with a frame 19 via a silicon substrate 12 for a heat sink. With such a configuration, a semiconductor laser device can be manufactured at lower cost than a configuration using a stem, and a large number of output terminals can be easily arranged. Also, the semiconductor laser chip 1, the monitoring light receiving element 4, and the signal detecting light receiving element 3
Can be two-dimensionally arranged, so that assembly is easy. In this embodiment, the light receiving element 4 for monitoring the laser beam and the light receiving element 3 for detecting the signal are formed on the silicon substrate for the heat sink. However, a configuration in which a plurality of chips are mounted may be used.
If necessary, at least one of the signal detection light receiving element 3 and the laser light monitoring light receiving element 4 may be mounted, and a plurality of each may be mounted. In the mounted light receiving element, the light receiving areas of all the light receiving elements may be multi-divided, or the light receiving areas of some light receiving elements may be multi-divided. With this configuration, the size, shape, and the like of the spot of the incident laser beam can be detected. Further, only one of the holographic grating and the diffraction grating may be formed on the optical element having the concave portion, or both may be formed, or a plurality of each may be formed. With such a configuration, functions such as beam splitting and focusing can be realized, and the functions can be easily controlled by the pattern of the holographic grating and the diffraction grating. Further, even when the semiconductor laser chip 1 and the light receiving element 3 are two-dimensionally arranged even when the reflecting mirror 18 and the semiconductor laser chip 1 are provided instead of the surface-emitting type semiconductor laser chip 1, assembly can be performed easily.

In the embodiment shown in FIG.
By using a resin material as the insulating material of the frame provided around the lead frame 20, the lead frame 20 provided with the frame around can be manufactured at low cost. Thus, a semiconductor laser device can be manufactured at low cost.

In the embodiments shown in FIGS. 1 to 6, the optical element having the concave portion may be made of a resin material transparent to laser light emitted from the semiconductor laser chip.
By using a resin for the optical element having the concave portion, the optical element can be manufactured at low cost. Thereby, a semiconductor laser device can also be manufactured at low cost.

[0029]

According to the present invention, the optical axis of the laser light when the laser light emitted from the semiconductor laser chip enters the optical element having the concave portion is substantially parallel to the inner surface of the concave portion of the optical element.
In addition, by providing a configuration in which the outer surface of the optical element has a tapered shape, it is possible to easily form the optical element and provide an excellent optical element and a semiconductor laser device that reduce stray light noise. .

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical element and a semiconductor laser device according to an embodiment of the present invention.

FIG. 2 is a sectional view of an optical element and a semiconductor laser device according to another embodiment of the present invention.

FIG. 3 is a sectional view of an optical element and a semiconductor laser device according to still another embodiment of the present invention.

FIG. 4 is a sectional view of an optical element and a semiconductor laser device according to still another embodiment of the present invention.

FIG. 5 is a sectional view of an optical element and a semiconductor laser device according to still another embodiment of the present invention.

FIG. 6A is a top view of a semiconductor laser device according to still another embodiment of the present invention, and FIG.

FIG. 7A is a top view of a semiconductor laser device according to still another embodiment of the present invention, and FIG.

FIG. 8 is an exploded perspective view of a conventional optical element and a semiconductor laser device.

FIG. 9 is a sectional view of an optical element and a semiconductor laser device using a resin.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 semiconductor laser chip 2 heat sink 3 signal detecting light receiving element 4 monitoring light receiving element 5 optical element 6 stem 7 electrode terminal 8 insulating member 9 chip mounting portion 10 cap 11 optical element 12 heat sink silicon substrate 13 laser light 14 holographic grating 15 Diffraction grating 16 Light receiving area 17 Surface-emitting type semiconductor laser chip 18 Reflector 19 Frame 20 Lead frame

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Akio Yoshikawa 1-1, Sachimachi, Takatsuki City, Osaka Prefecture Inside Matsushita Electronics Corporation (56) References JP-A-3-44992 (JP, A) JP-A Sho 63-62257 (JP, A) JP-A-63-197361 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01S 5/00-5/50 H01L 23/02-23 / 04

Claims (3)

(57) [Claims] A frame has a semiconductor laser chip, a light receiving element, and a concave portion on the side of the frame , and is made of an optical material transparent to laser light emitted from the semiconductor laser chip. Semiconductor mounted with an optical element molded in a mold
A laser device , wherein the semiconductor laser chip and the light receiving element are provided in the concave portion.
And an optical axis of the laser beam and at least one of the inner surfaces of the recess are substantially parallel to each other, and the optical element
A semiconductor laser device characterized in that the outer surface of the element is tapered . 2. One or more holographic gratings or one or more diffraction gratings or light comprising said holographic gratings and said diffraction gratings
The semiconductor laser device according to claim 1, further comprising a chemical element . 3. A frame is provided around a lead frame.
The semiconductor laser and the light receiving element
The semiconductor laser device according to claim 1 , wherein the semiconductor laser device is arranged in a room .