JPH05206522A - Optical semiconductor module - Google Patents

Abstract

PURPOSE:To substantially improve coupling efficiency by optically coupling a cap-sealed semiconductor laser and an optical fiber pigtail through the intermediary of a lens. CONSTITUTION:An aspherical lens 6 s used as a lens, the aspherical lens 6, which is fixed to a lens holder 7a, is resistance-welded (8) to a cap 9, a semiconductor laser 1 and an optical fiber pigtail 3 are optically coupled through the intermediary of the non-spherical lens 6, and an optical semiconductor module is constituted. As a result, coupling efficiency is sharply improved, and an optical semiconductor module, in which required coupling efficiency is sufficiently satisfied, can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor module, and more particularly, to an optical semiconductor module in which a cap-sealed semiconductor laser is optically coupled to an optical fiber pigtail via a lens. .

[0002]

2. Description of the Related Art A conventional optical semiconductor module will be described with reference to FIGS. FIG. 3 is a vertical cross-sectional view showing one example thereof, and FIG. 4 is a vertical cross-sectional view showing another conventional example. First, as shown in FIG. 3, a conventional optical semiconductor module is used.
Is a semiconductor laser with a cap 9 to which a glass plate 11 is fixed.
The laser 1 is hermetically sealed, and the semiconductor laser 1 is mounted on a holder 7 via a lens 6a, and an optical fiber pigtail 3
It has a structure optically coupled to.

Further, other conventional optical semiconductor modules are
As shown in FIG. 4, the semiconductor laser 1 is hermetically sealed with a cap 9 having a microlens 6b, and the semiconductor laser 1 is optically coupled to the optical fiber pigtail 3 via the microlens 6b. have. 3 and 4, 2 is a heat sink, 4 is a YAG welding point,
Reference numeral 5 is a slide ring, and 10 is a stem.

[0004]

By the way, the above-mentioned conventional optical semiconductor module has drawbacks and problems described in detail below. First, in the conventional optical semiconductor module shown in FIG. 3, since the glass plate 11 is interposed between the lens 6a and the semiconductor laser 1, the lens 6a cannot be brought close to the semiconductor laser 1. have. That is, considering the tolerance of the thickness of the cap 9 and the thickness of the glass plate 11 and the assembling machine precision, the limit is 1.13 mm. The magnification of the lens 6a is 2.54, which is the optimum magnification.
It cannot be 5.5, and the coupling efficiency is -7.
It was dB.

Next, the conventional optical semiconductor module shown in FIG. 4 has a structure in which the glass plate 11 of FIG. 3 is abolished and the microlens 6b is fixed to the cap 9. Therefore, the semiconductor laser 1 The distance between the microlens 6b and the microlens 6b is not restricted by the optical semiconductor module of FIG. However, in the manufacturing method of the microlens 6b, the glass plate is melted at a high temperature of 1000 ° C., and the surface tension is used for molding, so that the spherical aberration is large and the coupling efficiency is −10 dB even when optically coupled at the optimum magnification. Met. Since the required level of the product is -4 dB, there is a problem that the optical semiconductor module shown in FIG. 4 is not satisfactory.

Therefore, the present invention aims to solve the above-mentioned drawbacks and problems and to provide an optical semiconductor module having the above-mentioned required level, and in particular, the light whose coupling efficiency is greatly improved to -2 dB. An object is to provide a semiconductor module.

[0007]

The present invention is characterized in that an aspherical lens is used as a lens, and the aspherical lens is fixed to a cap or a lens holder / cap, whereby coupling efficiency is improved. Provides a significantly improved optical semiconductor module. That is, the present invention is an optical semiconductor module in which a semiconductor laser sealed with a cap and an optical fiber pigtail are optically coupled via a lens, wherein the lens is an aspherical lens, and The optical semiconductor module is characterized in that a spherical lens is fixed to the cap or the lens holder / cap.

[0008]

Embodiments of the present invention will now be described in detail with reference to FIGS. (Embodiment 1) FIG. 1 is a longitudinal sectional view of an optical semiconductor module showing an embodiment of the present invention, in which a semiconductor laser 1 is fixed to a heat sink 2 by soldering. Tosink 2
Is also fixed to the stem 10 with solder. On the other hand, the aspherical lens 6 is fixed to the lens holder 7a,
The lens holder 7a is fixed to the cap 9 by resistance welding 8, and the cap 9 and the stem 10 are fixed by resistance welding in a nitrogen atmosphere.

Due to this sealing, the semiconductor laser 1 is 1 ×
It is hermetically sealed at 10 ⁻⁸ atm · cc / sec or less, and the distance between the semiconductor laser 1 and the aspherical lens 6 can be made as short as 0.6 mm. Next, the tip portion of the optical fiber pigtail 3 is adjusted in position so that the light emitted from the semiconductor laser 1 is focused by the aspherical lens 6, and the YAG via the slide ring 5.
It is fixed by welding 4.

(Embodiment 2) FIG. 2 is a longitudinal sectional view of an optical semiconductor module according to another embodiment of the present invention, in which a semiconductor laser 1 is fixed to a heat sink 2 with solder. The heat sink 2 is also fixed to the stem 10 by soldering. On the other hand, the aspherical lens 6 has a lens holder 7b.
Fixed to the lens holder 7b and the stem 1
0 is fixed by resistance welding in a nitrogen atmosphere. The tip portion of the optical fiber pigtail 3 is adjusted in position so that the light emitted from the semiconductor laser 1 is focused by the aspherical lens 6, and is moved through the slide ring 5 to Y-axis.
It is fixed by AG welding 4.

The difference between the second embodiment and the first embodiment is that, in the second embodiment, as shown in FIG. 2, the lens holder 7b serves as a lens holder action and a cap for hermetically sealing a semiconductor laser. The lens holder 7a and the cap 9 of the first embodiment shown in FIG. 1 are integrated with each other. That is, the lens holder 7b according to the second embodiment is different from the first embodiment in that the lens holder 7b serves as a lens holder and a cap.

In both the first and second embodiments, the glass plate (see glass plate 11 in FIG. 3) of the cap that hermetically seals the semiconductor laser is abolished, whereby the semiconductor laser and the lens are removed. There is an effect that the constraint on the distance between them is eliminated and the optimum position can be fixed. Moreover, by using an aspherical lens as a lens for optical coupling,
A coupling efficiency of −2 dB is realized, and a coupling efficiency of the conventional optical semiconductor module is −7 dB (in the case of the conventional example of FIG. 3) and −10.
It is possible to provide an optical semiconductor module which is drastically improved as compared with dB (in the case of the other conventional example of FIG. 4) and the required coupling efficiency is sufficiently satisfied.

[0013]

As described in detail above, the present invention eliminates the restriction on the distance between the semiconductor laser and the lens by eliminating the glass plate for hermetically sealing the semiconductor laser.
Not only is it possible to fix the optimum position, but by using an aspherical lens as a lens for optical coupling,
It is possible to provide an optical semiconductor module in which the coupling efficiency is significantly improved and the required coupling efficiency is sufficiently satisfied.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an optical semiconductor module showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view of an optical semiconductor module showing another embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view of an optical semiconductor module showing a conventional example.

FIG. 4 is a longitudinal sectional view of an optical semiconductor module showing another conventional example.

[Explanation of symbols]

 1 Semiconductor Laser 2 Heat Sink 3 Optical Fiber Pigtail 4 YAG Welding Point 5 Slide Ring 6 Aspherical Lens 6a Lens 6b Micro Lens 7 Holder 7a Lens Holder 7b Lens Holder 8 Resistance Welding 9 Cap 10 Stem 11 Glass Plate

Claims (2)

[Claims] 1. An optical semiconductor module in which a semiconductor laser sealed with a cap and an optical fiber pigtail are optically coupled via a lens, wherein the lens is an aspherical lens, and the aspherical lens. An optical semiconductor module, wherein a lens is fixed to the cap. 2. An optical semiconductor module in which a semiconductor laser encapsulated with a cap and an optical fiber pigtail are optically coupled via a lens, wherein the lens is an aspherical lens, and the aspherical surface. An optical semiconductor module characterized in that the lens is fixed to the lens holder and cap.
Le.