JPH0634424B2 - Optical coupling device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optical coupling device that couples emitted light of a semiconductor laser element used for optical communication to an optical fiber.

[Conventional technology]

FIG. 2 is a sectional view showing a conventional semiconductor laser device and an optical coupling device for an optical fiber. As shown in the figure, the semiconductor laser device 1 is fixed on the chip carrier 2. The periphery of the optical fiber 3 is filled with solder 4, and the optical fiber 3 is fixed on the chip carrier 2 by aligning the tip of the optical fiber 3 so that the tip of the optical fiber 3 faces the light emitting portion of the semiconductor laser element 1. Parts are made up. The laser coupling portion is hermetically sealed in the package 5, and the optical fiber 3 is taken out through the side surface of the package 5 at the end opposite to the side facing the semiconductor laser device 1 to the outside of the package 5 and the side surface of the package 5. The optical fiber 3 is fixed to.

In the method of fixing the optical fiber 3, first, the solder 4 is heated to a temperature equal to or higher than the melting point and melted so that the optical fiber 3 can freely move in the solder 4. In this state, the optical fiber 3 is held and the axial alignment of the optical fiber 3 is adjusted in order to efficiently combine the optical fiber 3 and the emitted light 6 of the semiconductor laser element 1. The adjustment work is completed at the position where the coupling efficiency is maximized, the solder 4 is cooled and hardened, and the optical fiber 3 is fixed onto the chip carrier 2. Here, in many cases, the surface of the optical fiber 3 is coated with a metal thin film in order to increase the adhesive force with the solder 4. Further, the tip of the optical fiber 3 is often processed into a spherical shape in order to efficiently couple the emitted light 6 of the semiconductor laser element 1.

The chip carrier 2 is attached to the package 5 via the cooling element 7. The temperatures of the semiconductor laser device 1 and the chip carrier 2 can be controlled regardless of the temperature of the package 5. The electrical wiring for driving the semiconductor laser device 1 is composed of the input terminal A8a, the input terminal B8b and the thin gold wire A9.
a, the thin gold wire B9b is used. Here, the wiring to one input terminal B8b is often performed through the chip carrier 2 and the package 5. The other input terminal A8a is insulated from the package 5 by using an insulating material 10 such as glass.

[Problems to be solved by the invention]

In the conventional optical coupling device as described above, the equivalent circuit on the input side of the semiconductor laser device 1 can be simplified as shown in FIG. FIG. 3 is a diagram showing an equivalent circuit on the input side of the semiconductor laser device in the optical coupling device of FIG. In FIG. 3, Z _LD is the impedance of the semiconductor laser device 1, L _a is the inductance of the gold wire A 9 a, L _b is the inductance of the gold wire _{B 9 b} , and C _p is the capacitance of the cooling element 7. The equivalent circuit shown in FIG. 3 is a kind of filter circuit, and has an inductance L _b at a certain frequency.
And the capacitance C _p cause parallel resonance. Even if the semiconductor laser device 1 is driven at a high frequency for the purpose of using such an optical coupling device for high-speed optical communication, the amplitude and phase of the signal transmitted to the semiconductor laser device 1 are greatly changed, and the signal is used for communication. Is not suitable.

In order to reduce such a problem, the inductance L
Either or both of _b and the capacitance C _p may be reduced to increase the frequency band in which the influence of the filter circuit is large, to reduce the influence in the frequency band used for communication. However, since the capacitance C _p of the cooling element 7 is considered to be peculiar to the cooling element 7, the thin gold wire B9
It may be considered to reduce the inductance L _b of _b .

It is generally known that in order to reduce the inductance of the wire material, the diameter of the wire may be increased. However, if the thin gold wire B9b is made thicker, heat can be easily transferred, so that there is a problem in that a disconnection between the package 5 and the chip carrier 2 cannot be made, and the cooling capacity is lowered by the cooling element 7.

The present invention has been made to solve the above problems, and reduces the inductance of the wiring so that the semiconductor laser device can be driven at a high frequency.
An object of the present invention is to obtain an optical coupling device in which the cooling capacity of the cooling element does not decrease.

[Means for solving problems]

In the optical coupling device according to the present invention, the electrical wiring between the chip carrier and the package is made of a heat insulating material having a conductive metal plating on the surface, and the electrical wiring is performed by this.

[Action]

In the optical coupling device of the present invention, the heat insulation between the chip carrier and the package is maintained because the electric wiring is performed by using the heat insulating material having the surface provided with the conductive metal plating. Therefore, the cooling capacity of the cooling element is about the same as that of the above-described conventional device in which wiring is performed using the thin gold wire. On the other hand, since the inductance is reduced by increasing the cross-sectional area of the heat insulating material, the semiconductor laser device can be driven at a high frequency.

〔Example〕

FIG. 1 is a sectional view showing the configuration of an optical coupling device according to an embodiment of the present invention. Reference numerals 1 to 8, 9a and 10 in the drawing are the same as those of the conventional device shown in FIG. Also, the input terminal B8
Wiring between b and the chip carrier 2 is performed by using a ceramic 11 with gold plating.

By the way, the size of ceramics 11 with gold plating is
Since it can be made as large as the size of the chip carrier 2, the inductance corresponding to L _b shown in FIG. 3 becomes extremely small. Therefore, the input terminal A8a and the input terminal B
The semiconductor laser device 1 can be driven at a high frequency from 8b. On the other hand, the heat insulation between the package 5 and the chip carrier 2 is maintained to the same extent as in the conventional device, so that the cooling capacity of the cooling element 7 is not impaired.

In the above embodiment, as the heat insulating material having the surface coated with the conductive metal, the ceramics 11 coated with the gold plating is used.
However, the same effect as that of the above-described embodiment can be obtained by using another conductive metal plating or by using another heat insulating material.

Further, in the above embodiment, the emitted light 6 of the semiconductor laser device 1 is
Although the description has been given of the case where the optical fiber 3 is directly coupled to the optical fiber 3, the optical system such as a lens may be arranged between the semiconductor laser device 1 and the optical fiber 3, and the same effect as that of the above-described embodiment can be obtained.

Further, in the above-described embodiment, the case where the semiconductor laser device 1 is used has been described, but another light-emitting semiconductor device such as a light emitting diode may be used, and the same effect as that of the above-described embodiment is obtained.

〔The invention's effect〕

As described above, the present invention provides an optical coupling device,
Between the chip carrier and the package, electrical wiring was done using a heat insulating material with a conductive metal plating on the surface, so without impairing the cooling capacity by the cooling element,
The excellent effect that an optical coupling device capable of driving a semiconductor laser element at a high frequency can be obtained is obtained.

[Brief description of drawings]

FIG. 1 is a sectional configuration diagram showing an optical coupling device according to an embodiment of the present invention, FIG. 2 is a sectional configuration diagram showing a conventional semiconductor laser device and an optical coupling device of an optical fiber, and FIG. It is a figure which shows the equivalent circuit by the side of the input of the semiconductor laser element in the optical coupling apparatus of the figure. In the figure, 1 ... Semiconductor laser element, 2 ... Chip carrier, 3 ... Optical fiber, 4 ... Solder, 5 ... Package, 6 ... Emitted light, 7 ... Cooling element, 8a ... Input terminal A, 8b: input terminal B, 9a: thin gold wire A, 9b
...... Gold wire B, 10 …… Insulating material, 11 …… Ceramics. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Rumiko Suganuma 5-1-1, Ofuna, Kamakura-shi, Kanagawa Mitsubishi Electric Corporation Information Electronics Laboratory (72) Inventor Akihiro Adachi 5-1-1, Ofuna, Kamakura-shi, Kanagawa No. MITSUBISHI ELECTRIC CO., LTD. Information & Electronics Laboratory (56) References JP-A-62-112389 (JP, A)

Claims (3)

[Claims] 1. A semiconductor laser element, an optical fiber optically coupled to the semiconductor laser element, a chip carrier for holding the semiconductor laser element and the optical fiber, a cooling element for mounting the chip carrier, and the four elements described above. In an optical coupling device for accommodating elements, the package including the optical fiber from one end to the outside, wherein the chip carrier and the package also serve as a part of a power transmission line of the semiconductor laser device, the space between the chip carrier and the package. An optical coupling device characterized in that a heat insulating material having a conductive metal plating on its surface is used as the electric wiring. 2. The optical coupling device according to claim 1, wherein ceramics is used as the heat insulating material. 3. The optical coupling device according to claim 1, wherein a gold plating is used as the conductive metal plating.