JP3149965B2 - Optical semiconductor module - Google Patents

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 having a structure in which a semiconductor laser and an optical fiber pigtail are optically adjusted and mounted on a package. Related to

[0002]

2. Description of the Related Art Optical semiconductor modules used for optical fiber communication and the like have been conventionally provided as modules having an optical fiber pigtail for optical output. In many cases, the optical semiconductor module has a structure in which a semiconductor laser is optically adjusted to an optical fiber via a lens.

A conventional optical semiconductor module of this type will be described with reference to FIG. FIG. 2 is a longitudinal sectional view of a conventional optical semiconductor module, which includes a semiconductor laser 1, a heat sink 2, a chip carrier 3, a monitor photo diode 4, a selfoc microlens 21, It comprises a holder 22, a slide ring 8, a ferrule 9, an optical fiber 10, a Peltier element 12, and a package 13.

The selfoc microlens 21
Are fixed to a holder 22 by a hard solder 20. The semiconductor laser 1 is optically adjusted to a ferrule 9 via a SELFOC microlens 21, and the ferrule 9 is a slide ring. 8 and the holder 7 and Y
It is fixed by AG welding. Further, the holder 7
Is fixed to the package 13 by soldering with the Peltier element 12 interposed therebetween, and the ferrule 9 is
It is fixed to the side surface of the package 13 by the solder 11, and has a structure hermetically sealed at the same time.

[0005]

As shown in FIG. 2, a conventional optical semiconductor module generally has a holder 22 for holding a semiconductor laser 1, a selfoc microlens 21 and a ferrule 9. have. Incidentally, the coefficient of thermal expansion of the SELFOC microlens 21 is 115 × 10 ⁻⁷ deg ⁻¹ for the H lens. When fixing the SELFOC microlens 21 having such a coefficient of thermal expansion to the holder 22, in order to prevent the lens 21 from cracking, the materials of the hard solder 20 and the holder 22 have the above-mentioned coefficients of thermal expansion. A lens having a coefficient of thermal expansion close to that of the lens 21 is selected and used.

Conventionally, SS41 having a thermal expansion coefficient of 117 × 10 ⁻⁷ deg ⁻¹ has been used as a material of the selected holder 22. However, SS22 holder 22
The conventional optical semiconductor module using the above has a problem that the ambient temperature of the cooling capacity is 65 ° C. and cannot be adapted to the environmental temperature 70 ° C. required from the market.

Therefore, the present invention has a technical object to solve the above-mentioned problems, and in particular, to reduce cracks in an aspherical lens.
It is an object of the present invention to provide an optical semiconductor module that can prevent the occurrence of a cooling problem and improve the cooling capacity.

[0008]

According to the present invention, there is provided an optical semiconductor module in which an optical axis is adjusted via a lens in which a semiconductor laser and an optical fiber pigtail are fixed to a holder , wherein the holder is made of CuW. Comprising and said lens
So that the coefficient of thermal expansion takes a value close to that of CuW.
Heat of the lens and the holder
Prevent lens cracks caused by differences in expansion coefficients
In addition, the cooling capacity of the optical semiconductor module is improved.

That is, the present invention provides an optical semiconductor module in which the optical axis is adjusted via a lens in which a semiconductor laser and an optical fiber pigtail are fixed to a holder.
CuW and the lens has a coefficient of thermal expansion of Cu
An aspherical lens that takes a value close to the coefficient of thermal expansion of W
An optical semiconductor module, characterized in that the.

[0010]

The conventional optical semiconductor module uses the SELFOC microlens as described above. Since the coefficient of thermal expansion is 115 × 10 ⁻⁷ deg ⁻¹ , the coefficient of thermal expansion is An approximate SS41 (coefficient of thermal expansion 117 × 10 ⁻⁷ deg ⁻¹ ) holder must be used.

On the other hand, the present invention uses CuW instead of the conventional SS41 as the material of the holder, and this CuW has a thermal expansion coefficient of 70 ×.
Because it is 10 ^{@ 7 deg-1,} compared to the SS41, has excellent thermal conductivity, therefore, the heat of the holder can be efficiently released, it acts to improve the cooling capacity of the optical semiconductor module is produced Along with the lens crack
Can be prevented. In the present invention, this CuW
Of the lens holder to prevent cracking of the lens.
The reason for this is that an aspheric lens is used instead of the conventional Selfoc microlens. That is, the coefficient of thermal expansion of the aspherical lens can be adjusted by selecting the material component of the lens.
This is because the coefficient of thermal expansion of W can be approximated.

[0012]

Next, the present invention will be described in detail with reference to FIG. FIG. 1 is a longitudinal sectional view of an optical semiconductor module according to an embodiment of the present invention. A semiconductor laser 1 is fixed to a heat sink 2 using AuSn.
Are fixed to the chip carrier 3 with AuSn. On the other hand, an aspherical lens 6 is used as a lens, and this aspherical lens 6 is fixed to a CuW holder 7 with a low melting point glass 5.

Next, the chip carrier 3 is fixed to the CuW holder 7 by PbSn and YAG welding, and the monitor photodiode 4 is also fixed to the CuW holder 7 using PbSn. The ferrule 9 which is the tip of the optical fiber 10 is optically adjusted with the CuW holder 7 via the slide ring 8 and fixed by YAG welding. Peltier device 12
Is fixed to the package 13 with InSn, and the CuW holder 7 is fixed on the Peltier element 13 with InSn. The ferrule 9 is fixed by the package 12 and the solder 11, and is hermetically sealed at the same time.

The coefficient of thermal expansion of the aspherical lens is determined by selecting the material component of the lens.
Can be made close to 7 × 10 ⁻⁷ deg ⁻¹ , and by using the CuW holder 7, the cooling capacity as an optical semiconductor module is remarkably improved. That is, when compared at an environmental temperature of 70 ° C., the current consumption of the Peltier element is reduced by 5% to 10%, and the limit of the cooling capacity is improved from 70 ° C. to 75 ° C. further,
The thermal expansion coefficient of the aspherical lens is CuW for the holder made of CuW.
Aspherical lens that takes a value close to the coefficient of thermal expansion of
Is caused by the difference in the thermal expansion coefficient between the lens and the holder.
Cracks in the lens can be prevented.

[0015]

As described above, the present invention makes it possible to use a holder made of CuW by employing an aspherical lens. Compared to SS41, which is a material limited by the use of lenses, its heat conductivity is excellent, so it is possible to efficiently release the heat of the holder, which is the largest heat mass on the Peltier element, and therefore, as an optical semiconductor module This has the effect of improving the cooling capacity of the device. Furthermore, the coefficient of thermal expansion of the aspherical lens is
Take a value close to the thermal expansion coefficient of CuW of the CuW holder
By using an aspheric lens like this, the lens and holder
To prevent lens cracking due to the difference in thermal expansion coefficient between
It has an excellent effect that it can be performed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an optical semiconductor module according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a conventional optical semiconductor module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor laser 2 Heat sink 3 Chip carrier 4 Monitor photo diode 5 Low melting glass 6 Aspherical lens 7 CuW holder 8 Slide ring 9 Ferrule 10 Optical fiber 11 Solder 12 Peltier element 13 Package 20 Hard solder 21 Selfoc microlens 22 Holder

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-305587 (JP, A) JP-A-1-261601 (JP, A) JP-A-3-120884 (JP, A) 63669 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01S 5/00-5/50

Claims (1)

(57) [Claims] 1. A semiconductor laser and an optical fiber pigtail are
In an optical semiconductor module whose optical axis has been adjusted via a lens fixed to a holder , the holder is made of CuW
And the lens has a coefficient of thermal expansion of CuW.
An optical semiconductor module comprising an aspheric lens having a value close to a number .