JPH10142457A - Optical element module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cooling efficiency and reduce a shift of laser beam of a laser diode due to the brazing of a case by forming the case of specific alloy. SOLUTION: The case 11 has a case main body 13 and a bottom plate 16. The case main body 13 is provided with an optical fiber fitting member 12. On the top surface of the bottom plate 16, a chip carrier 19 is fixed which is formed of A/N, Cu, Cu/W, etc., so as to hold the laser diode 14 at constant temperature. On the top surface of a chip carrier 19, the laser diode 14 is provided and nearby the diode 14, a ball lens 22 is provided. The case main body 13 and bottom plate 16 is formed of alloy consisting of 1 to 4wt.% Cu, 1 to 5wt.% Ni, and 91 to 98wt.% W. The heat conductivity of this alloy is 120W/m.K and the coefficient of heat expansion is 4.4 to 5.7×10<-6> / deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element module such as a semiconductor laser module for optical communication, a semiconductor amplifier module, an external modulator module and a receiving module.

[0002]

2. Description of the Related Art The installation environment of this type of semiconductor laser module or the like, that is, the external atmosphere of the case of the laser module is 60 to 7 due to the generation of Joule heat of various electronic components.
A temperature of 0 ° C. is reached. The laser diode, which is widely used as a light source for high-speed optical fiber communication in this laser module, changes its optical characteristics such as its wavelength when the ambient temperature changes. Thermally shut off. That is, the conventional semiconductor laser module forms a hermetic package with a box-shaped case, and the interior of the package is filled with dry nitrogen gas to prevent the optical characteristics of the laser diode from changing due to a change in external temperature. doing.

[0003] As shown in FIG. 4, such a semiconductor laser module generally has a chip carrier 5 provided with a laser diode 4 fixed to the bottom of a case 1. A ball lens 9 held by a ball lens holder 8 is provided near the laser diode 4. A package 3 is provided between the bottom surface of the case 1 and the chip carrier 5.
A temperature control thermo module comprising a Peltier element for controlling the internal temperature of the device is interposed as required.

On the other hand, a glass plate 7a and a rod lens 7b, which are mounting members 7 for mounting the optical fiber 2 corresponding to the laser diode 4, are provided on one surface of the case 1, and the rod lens 7b is mounted on a rod lens holder 7c. The optical fiber 2 is held by the optical fiber holder 7d. As described above, since the glass plate 7a and the rod lens 7b are provided on one surface of the case 1, the case 1 of the conventional semiconductor laser module has the same thermal expansion coefficient as the glass plate 7a and the rod lens 7b. Fe
Consists of 54%, 29% Ni, 17% Co alloys (trade name: Kovar, hereinafter referred to as "Kovar") or 58% Fe, 42% Ni alloys (trade name: 42 alloy, hereinafter referred to as "42 alloy") Is done.

However, since Kovar or 42 alloy generally has a relatively low thermal conductivity, if the entire case is made of Kovar or 42 alloy, the temperature release inside the case is not effective, and the thermo module is not used. However, there is a problem that the cooling efficiency of the semiconductor laser module cannot be sufficiently increased even when the semiconductor laser module is used. In this case, it is conceivable to increase the number of semiconductor compound elements constituting the thermo module, but there is a problem that the semiconductor laser module becomes large.

To solve this problem, as shown in the figure, an optical fiber attaching member 7 is provided on a case body 1a made of Kovar or 42 alloy, and this case body 1a is mounted on a plate 1b made of a copper-tungsten alloy. A case of an optical element module to be attached is known. The thermal conductivity of copper-tungsten alloy (180 W / m · K) is about 10 times that of Kovar and 42 alloys (10-20 W / m · K). And has the property of being excellent in brazeability with 42 alloy. For this reason,
By mounting the laser diode 4 on the plate 1b made of the copper-tungsten alloy and brazing the case body 1a, the heat radiation from the plate 1b can be increased as compared with the case where Kovar or 42 alloy is used. It is expected that the cooling efficiency of the optical element module will be sufficiently increased by attaching a heat sink or the like having a high heat radiation effect to the plate 1b.

[0007]

As described above, copper-
Although the thermal conductivity of the tungsten alloy is higher than the thermal conductivity of Kovar or 42 alloy, at the same time, the average thermal expansion coefficient of the copper-tungsten alloy at 30 to 400 ° C. (7.5 × 10 ⁻⁶ /
° C) is the thermal expansion coefficient (4.5-5.
(1 × 10 ⁻⁶ / ° C.). For this reason, when the case body 1a and the plate 1b are brazed, the heat shrinkage of the case body 1a and the plate 1b during cooling after brazing cannot be ignored, and the thermo module 6, the chip carrier 5, and the laser diode 4 are optical fibers. There is a problem that it is easily displaced with respect to the mounting member 7.

That is, in the case of the optical element module shown in FIG.
Is much smaller than the case body 1a, and the case itself is deformed. Along with this deformation, the height of the laser diode 4 is displaced, and the light beam is displaced in the y-direction, which may cause the optical axis z of the rod lens 7b to not accurately coincide with the optical axis z. An object of the present invention is to provide an optical element module that can increase cooling efficiency and reduce a shift of laser light in a laser diode due to brazing of a case.

[0009]

The invention according to claim 1 is
As shown in FIG.
2, a case 11 facing the mounting member 12
Is an improvement of the optical element module in which the laser diode 14 is mounted. Its characteristic configuration is the case 11
Is 1 to 4% by weight of Cu, 1 to 5% by weight of Ni,
９８98% by weight of an alloy consisting of W.

In the optical element module according to the first aspect, the thermal conductivity of an alloy comprising 1 to 4% by weight of Cu, 1 to 5% by weight of Ni, and 91 to 98% by weight of W constituting the case 11 is described. Is 120 W / m · K. Compared to the case where the entire case is made of Kovar or 42 alloy, the heat inside the case is effectively transmitted to the outside, and the optical element is mounted on the case 11 by attaching it to a heat sink having a high heat radiation effect. Increase the cooling efficiency of the module. On the other hand, 1 to 4% by weight of Cu and 1 to 5%
The thermal expansion coefficient of an alloy consisting of Ni of 91 wt% and W of 91 to 98 wt% is 4.4 to 5.7 × 10 ⁻⁶ / ° C., and the thermal expansion coefficient of Kovar or 42 alloy is 4.5 to 4.5. 5.1 ×
10 ⁻⁶ / ° C.), and the deformation of the case 11 due to the difference in the heat shrinkage ratio when brazing by forming the case 11 from the same material is extremely small and can be ignored.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a first embodiment. The case 11 of the optical element module 10 according to this embodiment includes a case body 13 and a bottom plate 16. An optical fiber attachment member 12 is provided on the case body 13, and a laser diode 14 is mounted on the bottom plate 16. The optical fiber mounting member 12 is a glass plate 12a, a rod lens 12
b, rod lens holder 12c and optical fiber holder 1
2d. The rod lens 12b of the optical fiber mounting member 12 is held by a rod lens holder 12c, and the optical fiber 17 is held by an optical fiber holder 12d.

On the other hand, on the upper surface of the bottom plate 16, AlN, Cu, Cu /
A chip carrier 19 made of W or the like is fixed. The laser diode 14 is provided on the upper surface of the chip carrier 19, and a ball lens 22 held by a ball lens holder 21 is provided near the laser diode 14.
The lower peripheral edge of the case body 13 is brazed to the bottom plate 16, and the upper end is covered with a cover 23 made of the same material. The airtight package 24 is formed by covering the lower end and the upper end of the case body 13 in this way, and the inside of the package 24 is filled with dry nitrogen gas.

A feature of the present invention is that the case body 13 and the bottom plate 16 as the case 11 are made of Cu of 1 to 4% by weight.
And 1 to 5% by weight of Ni and 91 to 98% by weight of W (brand name: Ambiloy). This alloy has a thermal conductivity of 120 W / m · K and a coefficient of thermal expansion of 4.4 to 5.7 × 10 ⁻⁶ / ° C.

In the optical element module thus configured, the case body 13 and the bottom plate 16 as the case 11
4 wt% Cu, 1-5 wt% Ni, 91-98
Since it is composed of an alloy composed of W in weight%, its thermal conductivity becomes 120 W / m · K, and the bottom plate 16 effectively transmits the amount of heat released from the lower surface of the chip carrier 19 to the outside. The cooling efficiency of the optical element module can be sufficiently increased by attaching it to a highly effective heat sink or the like. On the other hand, 1 to 4% by weight of Cu,
Since the alloy composed of -5% by weight of Ni and 91-98% by weight of W has a thermal expansion coefficient of 4.4-5.7 × 10 ⁻⁶ / ° C., the thermal expansion coefficient of Kovar or 42 alloy (4 .5-
(5.1 × 10 ⁻⁶ / ° C.), and the deformation of the case 11 caused by the difference in the heat shrinkage ratio between the case body 13 and the bottom plate 16 made of the same material and brazed can be ignored.

FIG. 2 shows a second embodiment. 2, the same reference numerals as those in FIG. 1 denote the same components. Case body 33 of optical element module 30 in this embodiment
The five surfaces constituting the case 31 are integrally formed, and a side plate 36 constituting one side surface of the case 31 is brazed to the case body 33. Case body 33 and side plate 36
Is 1 to 4% by weight of Cu, 1 to 5% by weight of Ni,
The case body 33 is manufactured by a so-called powder metallurgy method of molding and sintering such an alloy powder. The optical fiber mounting member 12 is provided on the case body 33, and the chip carrier 19 is mounted on the side plate 36. The laser diode 14 is provided at a position facing the mounting member 12 of the chip carrier 19, and silver brazing is used for brazing the case body 33 and the side plate 36. The operation of the optical element module configured as described above is the same as that of the first embodiment, and the description thereof will not be repeated.

In the embodiment shown in FIG. 1 or FIG. 2, 1 to 4% by weight of Cu, 1 to 5% by weight of Ni,
The chip carrier 19 was directly mounted on the bottom plate 16 or the side plate 36 made of an alloy consisting of W of about 98% by weight, but as shown in FIG. 3, a Peltier element was provided on the upper surface of the bottom plate 16 or the side plate (not shown). The chip carrier 19 may be fixed via a thermo module 18 made of. That is, 1-4
A chip carrier 19 is provided on a bottom plate 16 or a side plate made of an alloy (trade name: Ambiloy) composed of weight% of Cu, 1 to 5 weight% of Ni, and 91 to 98 weight% of W via a thermo module 18. The laser diode 14 is fixed to the upper surface of the chip carrier 19 and the case body 13 is fixed.
Can be provided to face the fiber mounting member 12.

A thermo module 18 generally used for an optical element module includes a plurality of N-type semiconductor compound elements and a P-type semiconductor compound element.
The N-type semiconductor compound element is electrically connected in series in the order of N, P, N, and P, and a lead wire is connected to each of the N-type semiconductor compound and the P-type semiconductor compound at the end. When a positive voltage of the DC power supply is applied to the N-side terminal and a negative voltage is applied to the P-side terminal, current flows from the N-type of each element to the P-type,
The heat absorbed at the top is transported down through each element in parallel. As a result, heat is absorbed by the upper surface of the module 18 and is released to the lower surface of the module 18.

Therefore, in the optical element module to which the chip carrier 19 is fixed via the thermo module 18, the bottom plate 16 effectively transmits the amount of heat released from the lower surface of the thermo module 18 to the outside, and the bottom plate 16 has a high heat radiation effect. By attaching the optical element module to a heat sink or the like, the cooling efficiency of the optical element module can be further increased.

[0019]

As described above, in the optical element module according to the present invention, the case is made of 1 to 4% by weight of Cu and 1 to 5% by weight.
The thermal conductivity of the case is 120 W / m · Si because it is composed of an alloy consisting of Ni of 91 wt% and W of 91 to 98 wt%.
It becomes K. This thermal conductivity is higher than Kovar or 42 alloy, and effectively transfers the heat inside the case to the outside compared to the case where the entire case is made of Kovar or 42 alloy. As a result, in the optical element module of the present invention, the cooling efficiency of the optical element module can be increased and the optical element module can be made compact.

In addition, by increasing the cooling efficiency, when a thermo module is mounted inside the optical element module, the number of semiconductor compound elements constituting the thermo module can be reduced and power consumption can be reduced. Can reduce the resonance caused by the high frequency transmitted by the optical fiber.

Further, in the optical element module according to the present invention, the case has a thermal expansion coefficient of 4.4 to 5.7 × 10 ⁻⁶ / ° C.
This coefficient of thermal expansion is close to that of Kovar or 42 alloy (4.5 to 5.1 × 10 ⁻⁶ / ° C.). Therefore, the difference in the heat shrinkage ratio when the case is brazed can be ignored by making the entire case from the same material without lowering the reliability of attaching the glass plate or the rod lens to the case. As a result of ignoring the difference in the thermal shrinkage in this manner, in the optical element module of the present invention, the lens fixed to the case is also displaced by the same degree in the same direction due to the thermal shrinkage. The displacement can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical element module according to a first embodiment in which a chip carrier is mounted on a bottom plate of a case according to the present invention.

FIG. 2 is a sectional view of an optical element module according to a second embodiment in which a chip carrier is mounted on a side plate of a case according to the present invention.

FIG. 3 is a sectional view of an optical element module in which a thermo module is mounted on a bottom plate of a case according to the present invention.

FIG. 4 is a sectional view of a conventional optical element module corresponding to FIG.

[Explanation of symbols]

 10, 30 Optical element module 11, 31 Case 12 Optical fiber mounting member 14 Laser diode

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[Procedure amendment]

[Submission date] November 27, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

In the optical element module according to the first aspect, the thermal conductivity of an alloy comprising 1 to 4% by weight of Cu, 1 to 5% by weight of Ni, and 91 to 98% by weight of W constituting the case 11 is described. Is 120 W / m · K. Compared to the case where the entire case is made of Kovar or 42 alloy, the heat inside the case is effectively transmitted to the outside, and the optical element is mounted on the case 11 by attaching it to a heat sink having a high heat radiation effect. Increase the cooling efficiency of the module. On the other hand, 1 to 4% by weight of Cu and 1 to 5%
% By weight of Ni, the thermal expansion coefficient of the alloy comprising 91 to 98 wt% of W is 4.4~5.7 × 10 ^-6 / ℃, brazing by forming the case 11 from the same material In this case, the deformation of the case 11 due to the difference in the heat shrinkage is extremely small and can be ignored.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

In the optical element module thus configured, the case body 13 and the bottom plate 16 as the case 11
4 wt% Cu, 1-5 wt% Ni, 91-98
Since it is composed of an alloy composed of W in weight%, its thermal conductivity becomes 120 W / m · K, and the bottom plate 16 effectively transmits the amount of heat released from the lower surface of the chip carrier 19 to the outside. The cooling efficiency of the optical element module can be sufficiently increased by attaching it to a highly effective heat sink or the like. On the other hand, it is possible to ignore deformation of the case 11 due to the difference in the thermal shrinkage ratio in brazing the case body 13 and the bottom plate 16 is a same material.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction contents]

Further, in the optical element module according to the present invention, the case has a thermal expansion coefficient of 4.4 to 5.7 × 10 ⁻⁶ / ° C.
To become, to case without lowering the reliability of the mounting of the glass plate or rod lens, by constituting the entire case of the same material, the negligible difference of thermal shrinkage at the time of brazing the case I do. As a result of ignoring the difference in the thermal shrinkage in this manner, in the optical element module of the present invention, the lens fixed to the case is also displaced by the same degree in the same direction due to the thermal shrinkage. The displacement can be reduced.

Claims (1)

[Claims] An optical fiber mounting member (1) is attached to a case (11, 31).
2) provided, the case facing the mounting member (12)
In the optical element module in which the laser diode (14) is mounted inside (11, 31), the case (11, 31)) has 1 to 4% by weight of Cu, 1 to 5% by weight of Ni, An optical element module comprising an alloy comprising up to 98% by weight of W.