JPH11174280A - Semiconductor laser module and metallic ferrule - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solder adhesion property of the inside of a package and the outside, the softness capable of lessening optical axis misalignment and a technique capable of performing soldering work at low temp. relating to hermetic soldering of the ferrule of an optical fiber pigtail and the package. SOLUTION: This semiconductor laser module has a semiconductor laser 1 housed in the package 5 for shutting off the same from the outside and the optical fiber pigtail 4 for introducing the laser beam from the semiconductor laser 1 to the outside through a hole formed in the wall part of the package 5. The module is constituted as the structure which has a metallic ferrule 3 in at least the part penetrating the hole of the surface part of the optical fiber pigtail 4 and hermetically holds the through-part by soldering the metallic ferrule 3 to the package at the part of the hole. In such a case, the surface of the metallic ferrule 3 is provided with metallic layers consisting of a Sn metal film covering the surface thereof and an Au metal film covering the Sn metal film and the metallic ferrule 3 is soldered to the package 5 via the Au metal film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser module used for optical fiber communication and the like, and a metal ferrule used therefor.

[0002]

2. Description of the Related Art Semiconductor laser modules are generally
In order to suppress deterioration of characteristics of the semiconductor laser due to oxidation or the like, a structure is adopted in which outside air and the semiconductor laser are shut off.

FIG. 3 shows an example of the structure of a conventional semiconductor laser module. A cooling element 7 for cooling the semiconductor laser 1, a substrate 8 with a lens, a heat sink 10 for fixing the semiconductor laser 1, a chip-on carrier 9, a lens 2, and an optical fiber pigtail 4 for fixing the semiconductor laser 1 inside the package 5. A holder 11 and an optical fiber pigtail 4 are provided.

[0004] Laser light emitted from the semiconductor laser 1 is condensed by a lens 2 and is incident on an optical fiber. The upper part of the package 5 is sealed by a cap 6 resistance welding or the like.

There is a hole in the side wall of the package 5 for drawing the optical fiber pigtail 4 out of the package. A metal ferrule 3 is attached near the light incident end face of the optical fiber, and the inside and the outside of the package 5 are shut off by soldering a gap between the metal ferrule 3 and a hole in a side wall of the package.

[0006]

In the prior art, gold plating was applied to the surface of the metal ferrule 3 to facilitate soldering. Although a solder material such as PbSn has been used as a solder material for fixing the ferrule to the hole in the side wall of the package, since the hardness of PbSn is high, the light of the optical fiber pigtail 4 against the distortion due to the aging of the package 5 is increased. There has been a reliability problem that an axis shift occurs and the optical output from the fiber fluctuates.

Furthermore, the melting point of PbSn solder is about 18
3 ° C. and 200 to prevent thermal degradation of the fiber.
It was necessary to complete the work in a short time at a high temperature of 5 ° C. for 5 seconds, and there was a problem in the workability of assembly.

When In solder is used as a solder material, the melting point of which is lower than that of PnSn and which is softer, Ni and Au are used.
Poor adhesion between plated ferrule and In solder,
In a He leak test at a rate of 20 to 30%, there is a problem that a product which is not completely airtight exceeding 10-9 is generated.

Therefore, the present invention can reduce the solder adhesiveness for sufficiently shutting off the inside and the outside of the package and the optical axis deviation with respect to the conventional hermetic sealing soldering between the ferrule of the optical fiber pigtail and the package. It is an object of the present invention to provide a solder material which can be worked at a low temperature with softness and a technique for soldering.

[0010]

In order to solve the above-mentioned problems, according to the present invention, a semiconductor laser housed in a package for shielding from outside air and a laser beam from the semiconductor laser are provided on a wall of the package. An optical fiber pigtail that penetrates through the hole and leads to the outside, and at least a portion of the surface of the optical fiber pigtail that penetrates the hole has a metal ferrule, and the metal ferrule is soldered to the package at the hole. In the semiconductor laser module having a structure for maintaining the airtightness of the penetrating portion by attaching, a Sn metal film covering the surface and an Au metal film covering the Sn metal film are provided on the surface of the metal ferrule, and the Au metal film is interposed therebetween. It was configured to be soldered to the package. In this case, it is very preferable to use In (indium) for the solder for bonding the metal ferrule and the package.
Also, the Sn metal film and the Au metal film can be formed by metallizing Sn on the surface of the metal ferrule and metallizing Au on the surface. Further, the thickness of the Sn metal film may be about 4 μm and the thickness of the Au metal film may be about 1 μm. Further, the metal ferrule may have one end and the other end, and one end may penetrate the wall of the package and protrude to the outside of the package. on the other hand,
In the present invention, a metal disposed between the optical fiber pigtail and the hole for guiding a laser beam from a semiconductor laser housed in the package for shielding from outside air through a hole provided in a wall of the package to the outside. A ferrule,
It has a Sn metal film covering the surface and an Au metal film covering the Sn metal film.

By using In as the solder material,
Workability can be improved because work can be performed at a lower temperature than before.
Also, by metallizing Sn before metallizing Au as a metallization of the metal ferrule, solder adhesion to In is increased and the inside and outside of the package can be sufficiently isolated.

Further, by using In solder,
Since In is softer than PnSn, it is possible to suppress the distortion of the metal ferrule against the distortion of the package due to aging, to suppress the fluctuation of the light intensity from the optical fiber pigtail, and to improve the reliability. Can be.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. 1 and 2
It is a block diagram of the semiconductor laser module concerning this Embodiment.

In this example, a cooling element 7, a substrate with a lens 8, a chip-on-carrier 9, a heat sink 10, and a semiconductor laser 1 are mounted on the bottom surface inside a package 5 by soldering. The lens 2 is fitted in the substrate 8 with a lens.

The laser light emitted from the semiconductor laser 1 is condensed by a lens 2, and an optical fiber pigtail 4 attached to an emission side of the lens 2 via a holder 11.
He is incident.

FIG. 2 is a sectional view of the optical fiber pigtail 4 and the metal ferrule 3 used in the present embodiment. A metal ferrule 3 having a length of about 20 mm is attached to a light incident end of the optical fiber pigtail 4.

The metal ferrule 3 is about 5 m from the light incident end.
m, the metal ferrule 3 and the holder 11
Are not plated for the purpose of YAG welding, and a metal layer 15 is formed in other portions.

The metal layer 15 is formed by Sn plating (Sn metal film) having a thickness of about 4 μm in order from the surface of the metal ferrule 3.
And Au plating (Au metal film) having a thickness of about 1 μm to prevent oxidation of Sn plating.

The vicinity of the light incident end face of the optical fiber pigtail core wire 12 is plated with Au with a length of about 3 mm, and is soldered inside the metal ferrule 3 with AuSn solder for airtightness.

The light incident end face is mirror-polished at an angle of about 8 degrees with respect to the central axis of the optical fiber core wire 12.

The package 5 is plated with Sn and Au like the metal ferrule 3.

The metal ferrule 3 passes through a through hole provided in the side wall of the package 5 and is arranged so that the position of the plated portion of the metal ferrule 3 and the position of the through hole in the side wall of the package coincide.

The package 5 and the metal ferrule 3 are made of In
The soldering condition of In at this time is performed at a temperature of about 165 ° C. for a time of 15 seconds or less.

The semiconductor laser module thus manufactured has been confirmed by a He leak test to have an airtightness of 10-9 or less at a rate of 98% or more. In addition, a temperature cycle test of -40 to 85 ° C or 85 ° C
It was confirmed by the high-temperature storage test that the fluctuation of the optical output from the optical fiber pigtail 4 was sufficiently small.

[0025]

As described above, according to the present invention, by using In as the solder material, the work can be performed at a lower temperature than in the past, so that the workability can be improved. Also, by metallizing Sn before metallizing Au as the metallization of the metal ferrule, solder adhesion to In is increased and the inside and outside of the package can be sufficiently isolated. Further, by using In solder, PnSn
Since In is softer than solder, it is possible to suppress the distortion of the metal ferrule against the distortion of the package due to aging, to suppress the fluctuation of the light intensity from the optical fiber pigtail, and to improve the reliability. Can be.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a semiconductor laser module according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a metal ferrule part of the semiconductor laser module according to the embodiment.

FIG. 3 is a configuration diagram of a semiconductor laser module for explaining a conventional example.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Lens 3 Metal ferrule 4 Optical fiber pigtail 5 Package 6 Cap 7 In solder 8 Substrate with lens 3 Chip on carrier 10 Heat sink 11 Holder 12 Optical fiber core 13 PnSn solder 15 Metal layer

Claims (6)

[Claims] 1. A semiconductor laser housed in a package for shielding air from outside air, and an optical fiber pigtail for guiding laser light from the semiconductor laser through a hole provided in a wall of the package to the outside. Of the surface portion of the optical fiber pigtail, at least a portion penetrating the hole has a metal ferrule, and the metal ferrule was soldered to the package at the hole portion to maintain the airtightness of the penetrating portion, In the semiconductor laser module, a Sn metal film covering the surface and an Au metal film covering the Sn metal film are provided on the surface of the metal ferrule.
A semiconductor laser module characterized by being configured to be soldered to a package via a u-metal film. 2. The semiconductor laser module according to claim 1, wherein In (indium) is used for solder for bonding the metal ferrule and the package. 3. The Sn metal film and the Au metal film are formed by metallizing Sn on the surface of a metal ferrule and forming A on the surface.
3. The semiconductor laser module according to claim 1, wherein u is formed by metallization. 4. When the thickness of the Sn metal film is about 4 μm,
characterized in that the thickness of the u metal film is around 1 μm,
The semiconductor laser module according to claim 3. 5. The metal ferrule according to claim 1, wherein the metal ferrule has one end and the other end, and one end protrudes outside the package through a wall of the package.
5. The semiconductor laser module according to any one of items 1 to 4. 6. An optical fiber pigtail, which guides laser light from a semiconductor laser housed in a package for shielding from outside air through a hole provided in a wall portion of the package to the outside and the hole, is disposed between the hole. A metal ferrule for a semiconductor laser module, comprising: a Sn metal film covering a surface; and an Au metal film covering a Sn metal film.