JPH06307981A - Package for evaluating semiconductor optical modulator - Google Patents

Abstract

PURPOSE:To enhance the coupling efficiency between an optical fiber and a semiconductor optical modulator at the time of evaluation thereof. CONSTITUTION:Two alumina substrates 12 are bonded through an entirely metallized ground plane 16. A strip line 13 is made in any aluminum substrate 12 located oppositely to the ground plane 16. The alumina substrate 12 has a thickness (h) set equal to half of the element length of a semiconductor optical modulator 11. The semiconductor optical modulator 11 is bonded in a metal region 17 provided at the edge of the alumina substrate 12 and electrically connected with the ground plane 16 through the metal region 17. It is also connected with the strip line 13 through a bonding wire 14. The semiconductor optical modulator 11 has an edge 35 located substantially in parallel with the ground plane 16. This structure allows close arrangement of an optical fiber to the edge of the semiconductor optical modulator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package for evaluating a semiconductor optical modulator.

[0002]

2. Description of the Related Art FIG. 4 is a perspective view showing a package for evaluating a conventional semiconductor optical modulator. For example, the Institute of Electronics, Information and Communication Engineers, CI, No. 11, pp. 414-420
(November 1991).

An alumina substrate 30 is provided between the connectors 33, and a signal line 31 is provided on the upper surface of the alumina substrate 30.
And a ground plane 32 is formed. The signal line 31 is formed to have a length of 10 mm, for example. These form a coplanar waveguide with a characteristic impedance of 50Ω. The semiconductor optical modulator 11 is mounted on the signal line 31 at approximately the center of the coplanar waveguide.

FIG. 5 is an enlarged perspective view of the vicinity of the semiconductor optical modulator 11 having the configuration shown in FIG. In the semiconductor optical modulator 11, laser light 38 is made incident on the element modulation layer 37 from one cleaved end face 36, and modulated laser light 39 is obtained from the other cleaved end face 35. An optical fiber is generally used for the incidence of the laser light 38 on the end face 36 of the semiconductor optical modulator 11 and the extraction of the laser light 39 from the end face 35.

[0005]

The conventional semiconductor optical modulator evaluation package is constructed as described above, and when the coplanar waveguide is used, it is flush with the signal line 31 in order to maintain the characteristic impedance at 50Ω. Above it was necessary a ground plane 32 on both sides.

The ground plane 32 is the semiconductor optical modulator 11
Therefore, the optical fibers for guiding the laser beams 38 and 39 cannot be brought sufficiently close to the end faces 35 and 36 of the semiconductor optical modulator 11 because they are located outside the region where the semiconductor optical modulator 11 is mounted. The restriction on the position causes a problem that the coupling efficiency between the optical fiber and the semiconductor optical modulator 11 is lowered. Such a problem also occurs when a strip line is used instead of the coplanar waveguide.

The present invention has been made to solve the above-mentioned problems, and an optical fiber for inputting / outputting laser light is used as an end face of a semiconductor optical modulator while maintaining a characteristic impedance of a waveguide at a predetermined value. It is an object of the present invention to provide a semiconductor optical modulator evaluation package that can be brought even closer.

[0008]

A semiconductor optical modulator evaluation package according to the present invention evaluates a semiconductor optical modulator. The first and second dielectric layers, the conductive layer to be connected to the semiconductor optical modulator, and the first and second conductive bands to be connected to the semiconductor optical modulator are provided. The conductive layer is sandwiched between the first and second dielectric layers. The first and second conductive bands are selectively formed on the surface of each of the first and second dielectric layers opposite to the conductive layer.

Preferably, the first and second dielectric layers and the conductive layer have a notch for mounting the semiconductor optical modulator, and the first and second conductive bands pass in the vicinity of the notch.

[0010]

In the semiconductor optical modulator evaluation package according to the present invention, the semiconductor optical modulator to be evaluated is arranged so that its end face is substantially parallel to the conductive layer. Optical fibers for input and output can be arranged near the end face. Moreover, the characteristic impedance of the waveguide formed by the conductive layer, the first and second dielectric layers, and the first and second conductive bands can be appropriately designed.

[0011]

【Example】

First Embodiment: FIG. 1 is a perspective view showing the structure of a semiconductor optical modulator evaluation package according to the first embodiment of the present invention. The two alumina substrates 12 are bonded to each other via a ground surface 16 whose entire surface is metallized. A strip line 13 is provided on any of the alumina substrates 12 on the surface of the alumina substrate 12 opposite to the ground surface 16.

The thickness h of the alumina substrate 12 is set to half the element length of the semiconductor optical modulator 11. For example, if the element length of the semiconductor optical modulator 11 is 300 μm, the thickness h of the alumina substrate 12 is 150 μm. The width ω of the alumina substrate 12 is set to be sufficiently larger than the width d of the strip line 13. For example, the width ω of the alumina substrate 12
Is set to be sufficiently larger than 6 times the width d of the strip line 13. The width d of the strip line 13 is determined so that its characteristic impedance is 50Ω.

The semiconductor optical modulator 11 is bonded in the metal region 17 provided on the end face of the alumina substrate 12, and is electrically connected to the ground face 16 via the metal region 17. Further, it is connected to the strip line 13 by a bonding wire 14. Semiconductor optical modulator 11
End face 36 (not shown hidden in FIG. 1), 3
5 is positioned substantially parallel to the ground plane 16.

In the semiconductor optical modulator evaluation package having such a configuration, the characteristic impedance of the strip line 13 can be maintained at 50Ω up to the vicinity of the semiconductor optical modulator 11. Moreover, since the element length of the semiconductor optical modulator 11 and the thickness 2h of the two alumina substrates 12 are equal, the optical fiber 15 for inputting and outputting the laser light is positioned near the end faces 35 and 36 of the semiconductor optical modulator 11. be able to. Therefore, as compared with the conventional case, the coupling efficiency between the optical fiber 15 and the semiconductor optical modulator 11 can be improved.

Second Embodiment: FIG. 2 is a perspective view showing the structure of a semiconductor optical modulator evaluation package according to the second embodiment of the present invention. Compared with the first embodiment, two alumina substrates 12 are provided with notches 20 for mounting the semiconductor optical modulator 11.

In the notch 20, the semiconductor optical modulator 11
By mounting, there is a possibility that the bonding wire 14 connecting the semiconductor optical modulator 11 and the strip line 13 can be shortened. This is because the strip line 13 is the semiconductor optical modulator 11 in the first embodiment.
However, the strip line 13 is located on the side of the semiconductor optical modulator 11 in the second embodiment.

The second embodiment can achieve the same effects as the first embodiment, and is also effective from the viewpoint of reducing the inductance of the bonding wire 14.

Third Embodiment: FIG. 3 is a perspective view showing the structure of a semiconductor optical modulator evaluation package according to the third embodiment of the present invention. Compared with the first embodiment, two alumina substrates 12 are provided with a notch 21 for mounting the semiconductor optical modulator 11. Also, two alumina substrates 1
The strip line 13 provided in each of No. 2 is arranged in the direction perpendicular to the upper surface of the semiconductor optical modulator 11 in the first and second embodiments, but is arranged in parallel in the third embodiment. ing.

Moreover, although the strip lines 13 are opposed to each other in the first and second embodiments, they are not opposed to each other in the third embodiment. Since these are separated by the ground plane 16 which is a conductor, the positional relationship between the two hardly affects the characteristic impedance,
Even with such a configuration, the same effects as those of the first and second embodiments can be obtained. That is, in the present invention, the degree of freedom with respect to the position where the strip line 13 is formed is large.

[0020]

As described above, according to the semiconductor optical modulator evaluation package of the present invention, the semiconductor optical modulator can be provided between the optical fiber for optical input / output and the semiconductor optical modulator without deteriorating the characteristics of the waveguide. High coupling efficiency can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a first embodiment of the present invention.

FIG. 2 is a perspective view showing the configuration of a second embodiment of the present invention.

FIG. 3 is a perspective view showing the configuration of a third embodiment of the present invention.

FIG. 4 is a perspective view showing a conventional technique.

FIG. 5 is a perspective view showing a conventional technique.

[Explanation of symbols]

 11 Semiconductor Optical Modulator 12 Alumina Substrate 13 Stripline 16 Ground Surface 20, 21 Notch

Claims (2)

[Claims] 1. A semiconductor optical modulator evaluation package for evaluating a semiconductor optical modulator, wherein the semiconductor optical modulator evaluation package is sandwiched between first and second dielectric layers and the first and second dielectric layers. A conductive layer to be connected to the optical modulator, and a conductive layer that is selectively formed on a surface of each of the first and second dielectric layers opposite to the conductive layer and connected to the semiconductor optical modulator. A semiconductor optical modulator evaluation package comprising: a first conductive band and a second conductive band. 2. The first and second dielectric layers and the conductive layer have cutouts for mounting the semiconductor optical modulator, and the first and second conductive bands have cutouts. The semiconductor optical modulator evaluation package according to claim 1, which passes through the vicinity.