JPH06289258A - Semiconductor laser device - Google Patents

Abstract

PURPOSE:To eliminate the need for using low melting solder by forming a lens by direct molding on a laser carrier, then fixing a laser element onto the laser carrier. CONSTITUTION:The lens 2 is previously directly molded on the laser carrier 1. A laser sub-mounted fixed with a semiconductor laser element 3 atop this mount and a PD sub-mount 10 fixed with a photodiode (PD) 6 are aligned in optical axis to the lens 2 and are then fixed by soldering onto the laser carrier 1. Since the lens 2 is directly molded on the carrier 1, the assembly of the device is executed simply by aligning the optical axes of the semiconductor laser 3 and the lens 2, then directly fixing the semiconductor laser to the laser carrier 1 by the high melting solder, such as Au/Sn. The joint part by low melting solder is, therefore, eliminated and the generation of optical axis mis- alignment by moving of the lens by the fatigue of the low melting solder after assembly does not arise any more.

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 in which a semiconductor laser element is integrated with a lens and a photodiode (hereinafter referred to as "PD"), which is present in a conventional device by directly molding the lens into a laser carrier. It is characterized by eliminating solder joints with weak strength and improving reliability.

The semiconductor laser device according to the present invention can be used as a light source in the fields of optical communication and optical measurement, and has higher reliability than conventional devices.

[0003]

2. Description of the Related Art As a conventional example, JP-A-58-21890
The invention described in the publication is shown in FIG. In the conventional structure shown in FIG. 4, the semiconductor laser 3 and the lens 2 are separated into separate carriers 1 and 7.
After fixing each of them and moving the lens carrier 7 to align the optical axes of the lens 2 and the semiconductor laser 3,
And the laser carrier 1 was fixed by soldering.

[0004]

In the conventional example of FIG. 4, the lens carrier 7 is fixed to the laser carrier 1 by soldering. In that case, in the structure of FIG.
Is fixed with a high melting point solder (melting point of 200 ° C. or higher) such as Au / Sn, and then Pb /
There is no choice but to use a low melting point solder such as Sn (melting point 200 ° C. or lower). In general, low melting point solder has low strength and is susceptible to cracks and creeps due to temperature fluctuations and deterioration over time. As a result, there is a problem that the lens carrier 7 moves after assembly and the optical axis shifts, resulting in low reliability. .

[0005]

The above problems are caused by fixing the laser carrier and the lens carrier as separate members by soldering. Therefore, in the present invention, the lens and the laser element are mounted on the same carrier. Specifically, as described in the literature (Asahi Glass Co., Ltd. aspherical glass mold lens material), it is now possible to directly form a minute lens for a semiconductor laser on a metal member. A lens was formed by direct molding on the substrate, and then the laser element was fixed on the laser carrier.

[0006]

According to the present invention, since the lens is directly molded on the laser carrier, the device can be assembled simply by aligning the optical axis of the semiconductor laser with the lens and then directly fixing it to the laser carrier with a high melting point solder such as Au / Sn. good. Therefore, the above-mentioned problem that the joint between the laser carrier and the lens carrier due to the low melting point solder is eliminated in the conventional device and the lens moves due to fatigue of the low melting point solder after assembly to cause the optical axis shift is solved.

[0007]

FIG. 5 and FIG. 6 are perspective views of an embodiment of the present invention,
FIG. The lens 2 is directly formed on the laser carrier 1 in advance. The laser submount 9 having the semiconductor laser element 3 fixed to the upper surface and the PD submount 10 having the PD 6 fixed thereto are aligned with the lens 2 in the optical axis. Soldered on top.

Each member and the assembling process will be described below. Laser carrier 1 shown in FIG. 7, lower Kovar or Cu-W alloy or the like having a linear expansion coefficient (both linear expansion coefficient ⁶ × 10¯ 6
Approximately) is used as a material, and the dimensions are about several mm square. As shown in the figure, it has a vertical wall plate and the surface is plated with Au for soldering. A hole 13 having a diameter of about 1 mm is formed in the wall plate for lens molding.

Next, as shown in FIG. 8A, a lens mold 14 is disposed so as to sandwich the hole 13 of the laser carrier 1, and a lens material 15 is filled so as to fill the hole 13 therebetween. Then, the lens 2 is formed into a laser carrier 1 by firing, as shown in FIG.

On the other hand, as shown in FIGS. 8 (c) and 8 (d), P
D6 is soldered and fixed to the PD submount 10 made of ceramic, and the semiconductor laser element 3 is soldered and fixed to the laser submount 9 made of ceramic as shown in FIGS. For soldering these, Au / Sn (melting point 280
Use a high melting point solder such as (° C). Then, first, the PD submount 10 of (d) is arranged on the laser carrier 1 so that the optical axis of the PD submount 10 is aligned with the lens 2, and is fixed with a high melting point solder such as Au / Sn.

Next, the laser submount 9 of (f) is fixed on the laser carrier 1 with a high melting point solder such as Au / Sn after aligning the optical axes of the laser element 3 and the lens 2. At the time of soldering, the Au / Sn solder between the laser 3 and the laser submount 9 and the PD 6 and the PD submount 10 which are previously fixed melts, but the laser element 3 and the PD 6 move largely due to the viscosity of the molten solder. Therefore, it does not hinder the alignment. Thus, the semiconductor laser device described in the present invention is completed.

In the present invention, since the lens is directly molded on the laser carrier, it is not necessary to use the low melting point solder as in the conventional example, and the optical axis deviation between the lens and the laser element is unlikely to occur.

By the way, in the direct molding of the lens, if the linear expansion coefficient of the lens and the metal base for molding the lens are largely different from each other, the lens may be cracked during molding. Therefore, the linear expansion coefficient of the metal base is the linear expansion coefficient of the lens. It is necessary to make it 0.8 to 1.2 times the coefficient. As described above, the thermal conductivity of the metal material limited by the value of the linear expansion coefficient cannot be expected to be necessarily high, but the semiconductor laser emits heat of several tens mW to several hundreds mW at the time of oscillation, which improves the exhaust heat. Therefore, it is desirable that the metal base on which the laser is mounted has high thermal conductivity.

In order to satisfy these conditions, a lens base 18 having a linear expansion coefficient matched to that of a lens and a laser base 19 having a high thermal conductivity are vertically brazed and integrated into a laser carrier 1. An example of this is shown in FIG. In an embodiment, Fe-Ni alloy (coefficient of linear expansion 8 × 10¯ ⁶ as a lens base 18, the thermal conductivity of 0.03 [Cal / c
The msec ℃]), Cu-W alloy (coefficient of linear expansion ⁶ × 10¯ 6 as a laser base 19, the thermal conductivity of 0.7 [Cal
/ Cmsec ° C]) is used.

In the above embodiments, the laser device 3 and the PD
Both of 6 are once soldered to the submount and the positioning is performed by operating the submount. However, if the semiconductor element is directly grasped and moved, there is a possibility that the semiconductor element may be broken due to a work mistake. Because there is.

The present invention can be basically realized without a submount. In FIGS. 1, 2 and 3, the laser element 3 and the PD 6 are directly mounted on the laser carrier 1 without using the submount. An example of soldering is shown. In this case, as the material of the laser carrier, Kovar or Cu-W alloy having a low linear expansion coefficient is used as in the previous case.

On the other hand, as described above, when the matching of the linear expansion coefficient with the lens and the exhaust heat of the laser pose a problem, the linear expansion coefficient is adjusted to the lens as shown in FIG. A lens base made of metal and a laser base made of metal having a high thermal conductivity are brazed and integrated to be used as a laser carrier. The materials of the lens base and the laser base are the same as above.

[0018]

According to the present invention, since the lens is directly molded on the laser carrier, there is an effect that it is not necessary to use a low melting point solder.

[Brief description of drawings]

FIG. 1 is a perspective view of a semiconductor laser device according to the present invention.

FIG. 2 is a top view of a semiconductor laser device according to the present invention.

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

FIG. 4 is a perspective view of a semiconductor laser device according to a conventional technique.

FIG. 5 is a perspective view of an embodiment according to the present invention.

FIG. 6 is a sectional view of an embodiment according to the present invention.

FIG. 7 is an explanatory diagram of a laser carrier by a trigonometric method.

FIG. 8 is an assembly process diagram of a semiconductor laser device according to the present invention.

FIG. 9 is an explanatory diagram of an embodiment in which a lens carrier is brazed to a lens base and a laser base.

FIG. 10 is an explanatory diagram of an embodiment in which a lens carrier is brazed to a lens base and a laser base, and a submount is not used.

[Explanation of symbols]

1 ... Laser carrier, 2 ... Lens, 3 ... Semiconductor laser element, 6 ... PD (photodiode), 9 ... Laser submount, 10 ... PD submount.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuo Kumazawa 502 Kintatemachi, Tsuchiura, Ibaraki Prefecture

Claims (5)

[Claims] 1. A laser carrier made of metal, which has a vertical wall plate, a hole is formed in the wall plate, and a glass lens is directly molded so as to fill the hole, and at least one It consists of a semiconductor laser element whose surface is metallized and a photodiode whose back surface of the light-receiving surface is metallized, and the metallized surface of the semiconductor laser element and the metallized surface of the photodiode are soldered to the surface of the laser carrier, A semiconductor laser device characterized in that laser light emitted from the front surface of the semiconductor laser element is condensed by a lens, and monitor light emitted from the rear surface is received by a photodiode. 2. A metal laser carrier having a vertical wall plate, a hole formed in the wall plate, and a glass lens formed by direct molding so as to fill the hole, and at least one laser carrier. A metallized semiconductor laser device consisting of a semiconductor laser device whose surface is metallized, a photodiode whose back surface is metallized, and a laser submount and a photodiode submount which are metallized on multiple surfaces. Surface and the metallized surface of the laser submount are soldered, the other metallized surface of the laser submount is soldered to the surface of the laser carrier, and the metallized surface of the photodiode is soldered to the metallized surface of the photodiode submount. Attached, the other metallized surface of the photodiode submount It is soldered on the surface of the laser carrier, and the laser light emitted from the front surface of the semiconductor laser device is condensed by the lens, and the monitor light emitted from the rear surface is received by the photodiode. Semiconductor laser device. 3. A semiconductor laser device according to claim 1, wherein Kovar or a Cu—W alloy is used as a material for the laser carrier. 4. The lens base according to claim 1, which is a metal plate having a linear expansion coefficient of 0.8 to 1.2 times the linear expansion coefficient of the lens, and a metal having a higher thermal conductivity than the lens base. A laser base, which is a plate made by, is vertically brazed and integrated to form a laser carrier, a lens is formed on the lens base, and a laser submount with a semiconductor laser element fixed and a photodiode with a photodiode fixed. A semiconductor laser device with a diode submount fixed on a laser base. 5. The Fe-Ni alloy as a lens base material and Cu as a laser base material according to claim 4.
-A semiconductor laser device using a W alloy.