JPH06308356A - Parallel transmission optical module - Google Patents

Abstract

PURPOSE:To provide a parallel transmission optical module capable of assembling without performing the work for adjusting an optical axis. CONSTITUTION:The parallel transmission optical module is constituted of a base substrate A forming pin guide parts 3a, 3b, a light receiving/light emitting element B whose electrode connected to a wiring circuit is patterned on a surface 4a opposite to the base substrate A and an optical fiber array C where plural pieces of optical fibers 9 are arranged, and the pin guide parts 10a, 10b are formed on both side parts and coinciding the optical axis of the optical fiber 9 with the optical axis of the light receiving/light emitting element B by arranging coupling pins 11a, 11b. Then, the minute recessed parts 12a making a pair each other are carved on respective opposing surfaces 1a, 4a in the base substrate A and the light receiving/light emitting element B, and the light receiving/light emitting element B is mounted on the base substrate A by interposing positioning members 13 on the minute recessed parts 12a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel transmission optical module, and more particularly to a parallel transmission optical module that does not require adjustment of the optical axes of the light receiving / light emitting element and the optical fiber array.

[0002]

2. Description of the Related Art Conventionally, a parallel transmission optical module used in the field of optical communication has a structure as shown in FIG. That is, in the module shown in FIG. 1, first, the heat sink 14 is provided with a laser die auto array (LD array) and a light emitting diode array (LE).
A light receiving / light emitting element 15 represented by a D array) is fixed. The optical fiber array 16 is arranged so as to face the light receiving / light emitting surface of the light receiving / light emitting element. At this time, the optical axes of the optical fibers of the optical fiber array and the optical axes of the light receiving / light emitting elements are aligned by using a fine movement adjusting device (not shown). Then, after the optical axes of both are adjusted, the heat sink 14 and the optical fiber array 1
A light receiving / light emitting element 1 is provided by interposing a connecting member 17 between 6 and joining them by a method such as adhesion, soldering or welding.
The positional relationship between the optical fiber array 5 and the optical fiber array 16 is fixed.

Besides the module of this structure, for example,
As disclosed in JP-A-1-291204,
There is also proposed a module having a structure in which an optical fiber array and a waveguide type optical component are connected by a connecting pin common to both. With this structure, the optical fiber array and the waveguide optical component are pre-positioned with pin guide grooves so that their optical axes coincide with each other when they are butted against each other. Since the optical axes of both of them coincide with each other only by inserting the connecting pin in common in the pin guide groove, there is an advantage that the module can be assembled without performing the optical axis adjustment work as described above. .

[0004]

By the way, in the former module, the adjustment of the optical axes of the light-receiving / light-emitting elements and the optical fiber array includes only one time when each element is set in the fine adjustment device. A working time of several minutes to ten and several minutes is required. In particular, when the light receiving / light emitting element is an LD array, there is a problem that a longer adjustment time is required because the allowable error when adjusting the optical axis is on the order of submicron.

The latter coupling method is a method of coupling the optical axes without adjustment. However, when this method is applied to the assembly of a parallel transmission optical module, it is necessary to mount the light receiving / light emitting element fixed on the heat sink with a high level of positional accuracy. If this positional accuracy is poor, the optical axes of the two cannot be coincident with each other as a practical problem.

The present invention solves the above-mentioned problems in assembling a parallel transmission optical module and improves the accuracy of the mounting position of the light receiving / light emitting element to perform the optical axis adjustment work of the light receiving / light emitting element and the optical fiber array. It is an object of the present invention to provide a parallel transmission module that can be assembled without performing the above, and can be manufactured at low cost and with high productivity, in particular, a parallel transmission optical module when the light receiving / light emitting elements are LD arrays.

[0007]

To achieve the above object, in the present invention, pin guide portions (I) are formed on both side portions of the surface on which a plurality of wiring circuits are patterned. A base substrate and a predetermined position on the surface of the base substrate are mounted by a flip chip method,
A light-receiving / light-emitting element in which electrodes connected to the wiring circuit are patterned, and a plurality of optical fibers are arranged on a surface facing the base substrate, and pin guide portions (II) are formed on both side portions thereof. An optical fiber array in which the optical axis of the optical fiber is aligned with the optical axis of the light receiving / light emitting element by disposing a connecting pin common to the pin guide portion (I) and the pin guide portion (II). In the parallel transmission optical module, the light-receiving / light-emitting element is formed by engraving minute recesses that form a pair on opposing surfaces of the base substrate and the light-receiving / light-emitting element, and interposing a positioning member in the minute recesses. Is provided on the base substrate, and a parallel transmission optical module is provided.

[0008]

When the base substrate and the light-receiving / light-emitting element are superposed on each other, the minute concave portions having the facing surfaces thereof are paired and overlap each other. Then, the minute recesses are formed with high precision by etching, for example. Therefore, when a positioning member, such as a sphere, which is common to the minute recesses is interposed and the two are superposed, the base substrate and the light-receiving / light-emitting element overlap with each other through the sphere. That is, the light receiving / light emitting element is mounted at a predetermined position on the base substrate.

Further, since the pin guide portion (I) of the base substrate and the pin guide portion (II) of the optical fiber array are formed in advance in a predetermined positional relationship calculated based on the design standard, these pins are formed. If the optical fiber array and the base substrate are coupled with the connecting pin common to the guide part (I) and the pin guide part (II), the optical fiber in the optical fiber array will have a predetermined position according to the design standard. Is located in.

Therefore, the optical axes of the light receiving / light emitting element at the predetermined position and the optical fiber at the predetermined position coincide with each other. That is, the optical axis-adjusted parallel transmission optical module can be obtained only by mechanically assembling the above-mentioned base substrate, light-receiving / light-emitting element, and optical fiber array without performing the optical-axis adjustment work.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical module of the present invention will be described below with reference to the drawings. FIG. 2 is an exploded perspective view showing an embodiment in which the light receiving / light emitting elements are LD arrays. In the figure, the base substrate A is usually composed of Si single crystal.
In order to supply an electric signal for driving an LD array described later from a drive circuit (not shown) to one surface 1a of the base substrate A, a plurality of wires (four wires in the figure) made of, for example, aluminum. The circuit 2 is patterned in a desired pattern. Grooves 3a and 3b each having a V-shaped cross section are formed as pin guide portions (I) on the surfaces 1a on both sides of the wiring circuit 2.

At a predetermined position A ₁ on the surface 1a of the base substrate A, the LD array B is mounted by the flip chip method. In this LD array B, the surface 4a on the side opposite to the surface 1a of the base substrate A, that is, the epitaxial crystal growth surface, is formed by metallizing, for example, Au as shown in FIG. 4) electrode 5
, And four light emitting portions 6 are formed at intervals of, for example, 250 μm on the surface 4b on the side optically coupled with the optical fiber described later.

When this LD array B is mounted on a predetermined position A ₁ of the base substrate A by the flip chip method, the surface 1b of the base substrate A and the surface 4b of the LD array B are formed on the same surface, and at the same time as the wiring circuit 2. The electrode 5 is connected, and the light emitting section 6 can emit light by an electric signal from a drive circuit (not shown). On the other hand, in the optical fiber array C,
4 on one surface 7a with a predetermined depth, a predetermined width, and a predetermined interval.
A groove 8 of a book is engraved, and an optical fiber 9 is arranged in each groove. Grooves 10a and 10b having V-shaped cross sections are formed as pin guide portions (II) on the surfaces 7a of both sides of the optical fibers 9, respectively. This V
Connection pins 11a, 1 described later are provided in the character grooves 10a, 10b.
The optical fiber 9 and the connecting pins 11a and 11b are arranged at predetermined positions on the surface 7a of the optical fiber array C by placing the optical fiber 9 and the connecting pins 11a and 11b on the entire surface of the optical fiber array C by disposing the pressing cover C'on the entire surface. It is fixed to.

In the present invention, a plurality of (four in the figure) minute recesses 12a are formed in a predetermined position A ₁ of the base substrate A, and the LD array B mounted at the predetermined position A ₁ is formed. Similarly, four minute recesses 12b are formed in the surface 4a. Micro recess 12a and LD on the base substrate A side
The arrays 12b on the side of the array B have a pair of shapes, and at the same time, when these minute recesses are overlapped facing each other, the LD array B is mounted at the above-mentioned predetermined position A ₁ , that is, the light emitting section 6 is formed. Are engraved so as to be arranged at a predetermined position based on the design standard.

These minute recesses 12a and 12b are usually formed by combining photolithography technology and etching. Accordingly, the size and shape of the minute recesses 12a and 12b themselves have a very high accuracy in accordance with the dimensional accuracy of the mask material used, and the error in the engraving position from the design reference position is very small. can do.

A positioning member 13 is provided in each of the minute recesses 12a and 12b, and a predetermined position A of the base substrate A is provided.
_The LD array B is mounted on ₁ . Specifically, the positioning member 13 is put in the minute recess 12 a of the base substrate A, and the minute recess 12 b of the LD array B is placed on the positioning member 13.
It is implemented by fitting. Since these minute recesses are formed with high positional accuracy based on the design standard, the mounted LD array B is arranged at the predetermined position A ₁ based on the design standard.

Here, the positioning member 13 provided in the minute recess has a diameter error of 1% or less, such as a quartz glass ball used as a spacer for a liquid crystal panel. It is preferably a sphere having accuracy. Further, it is preferable that the minute recesses are pyramid-shaped recesses into which about ⅓ of the diameter of the sphere is fitted when the sphere is used as the positioning member.

When the minute recesses are pyramidal and the positioning member is a sphere, for example, the minute recesses 1 on the base substrate A are used.
FIG. 4 shows a state in which the sphere 13 is fitted in 2a. The V-shaped grooves 3a and 3b of the base substrate A are formed by the above-mentioned minute recesses 12
After engraving a by etching, it is preferable to engrave by etching again with the minute recesses masked. This is because it is possible to improve the positional accuracy of the V-shaped groove. However, if it is not desired to repeat the photolithography and etching processes twice, for example, even if the minute recess 12a is engraved and then the minute recess 12a is used as a position reference, machining is performed on the surface 1a in a submicron range. It is also possible to provide position accuracy on the order.

The V-shaped groove 8 in the optical fiber array C is also preferably engraved by combining photolithography technology and etching. The positional accuracy of the optical fibers 9 arranged in the V-shaped groove 8 can be increased, and as a result,
This is because these optical fibers 9 can be arranged at positions based on the design criteria. The V-shaped grooves 10a and 10b in the optical fiber array C are the V-shaped grooves of the base substrate A.
It may be carved in the same manner as the character grooves 3a and 3b.

The optical fibers 9 to be arrayed may have a polished tip shape, but in order to improve the optical coupling efficiency with the LD array B, the tip is lens-processed, or the tip is lens-finished. Further, a lens such as a spherical lens or an array lens may be added. The parallel transmission optical module of the present invention is assembled as follows.

First, a pyramid shape as shown in FIG. 4 was formed.
Minute recess 12a and V-shaped groove 3 that is the pin guide portion (I)
a and 3b are engraved on the surface 1a as shown in FIG.
A base substrate A is prepared. As this base substrate A
Is a predetermined position A in the wiring circuit 2. ₁Is, for example, 15
Flip chip supplied with solder of about 20 μm
It is preferable that the solder pad 2a for bonding is used.
Good

The base substrate A is then set on the heating table. Then, a sphere 13 having a predetermined diameter is picked up by a vacuum suction tool, and these are placed in all the minute recesses 12a. At this time, the sphere 13 becomes the minute recess 12
In the case where the protrusion from a occurs, for example, the spheres 13 are coated with a thermosetting adhesive in advance, and when the spheres 13 are placed in the minute recesses 12a, the base substrate A is tens of tens with a heating table. The spheres 13 may be bonded and fixed in the minute recesses 12a by heating to a temperature of ° C to cure the thermosetting adhesive.

Then, the LD array B as shown in FIG.
Is picked up by a vacuum suction tool with the surface 4a facing down, and the minute recesses 12b are the minute recesses 1 of the base substrate A.
The LD array B is placed on the base substrate A so as to wrap the spheres 13 projecting from the 2a by, for example, about 2/3, and the whole is heated. At this time, the fine concave portion 12b and the spherical body 13 may be aligned with each other by performing image recognition on both by using a highly accurate image recognition device.

At this time, as shown in FIG. 5, for some reason, the alignment between the minute concave portion 12b and the spherical body 13 may be displaced. However, also in this case, the solder of the solder pad 2a adheres to the electrode 5 in a molten state.
Then, at that time, a force in the direction indicated by the arrow p acts on the LD array B due to the surface tension of the molten solder. As a result, LD array B moves slightly to the left in the figure,
As shown in FIG. 6, the alignment of the sphere 13 and the minute recess 12b is realized, and at the same time, the solder of the solder pad 2a can be solidified in a regular state. Thus, if the portion of the wiring circuit 2 at the predetermined position A ₁ is configured as a solder pad for flip-chip bonding, it is effective because the self-alignment function can be exhibited.

After mounting the LD array B on the predetermined position A ₁ of the base substrate A in this manner, the connecting pins 11a and 11b protruding from the optical fiber array C are respectively connected to the V-shaped grooves 3a and 3a of the base substrate A. 3b, the base substrate A and the optical fiber array C are connected to each other, and a solder having a melting point lower than that of the solder used in the adhesive or the solder pad is used to join the two to assemble the optical module of the present invention. Complete.

In the embodiment, the LD array B is 4
Although the description has been made using the one in which the LDs are arranged in parallel, for example, 8
When mounting an LD array of more than channels, since it is elongated, a minute recess in the center of the LD array-
A spherical structure may be formed to prevent the entire deflection. Further, in the embodiment, the pin guide portion (I) and the pin guide portion (II) are both V-shaped grooves, but these pin guide portions are not limited to this shape. It may be a hole formed in the thickness portion of the base substrate and the optical fiber array.

[0027]

As is apparent from the above description, the parallel transmission optical module of the present invention can be assembled without performing the optical axis adjusting work as in the prior art, and therefore the productivity at the time of manufacturing is increased, Therefore, the cost is low,
Its industrial value is great.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a conventional parallel transmission optical module.

FIG. 2 is an exploded perspective view showing an example of a parallel transmission optical module of the present invention.

FIG. 3 is a perspective view showing an LD array of the present invention.

FIG. 4 is a perspective view showing an example of a minute recess and a positioning member of the present invention.

FIG. 5 is a partial cross-sectional view showing a state in which the base substrate and the LD array are displaced when the parallel transmission optical module of the present invention is assembled.

FIG. 6 is a partial cross-sectional view showing a state where regular alignment is performed between the base substrate and the LD array.

[Explanation of symbols]

A base substrate B LD array (light receiving / light emitting element) C optical fiber array C'holding cover for optical fiber array 1a surface of base substrate A 1b joint surface of base substrate A with optical fiber array C 2 wiring circuit 2a flip chip joining Solder pad 3a, 3b V-shaped groove (pin guide portion (I)) 4a Surface of LD array B (epitaxial crystal growth surface) 4b Bonding surface with optical fiber of LD array B 5 Electrode 6 Light emitting portion 7a Optical fiber array C Surface 7b Joint surface of optical fiber array C with base substrate 8 Optical fiber array V-shaped groove 9 Optical fibers 10a, 10b V-shaped groove (pin guide part (II)) 11a, 11b Connecting pin 12a Base substrate A Side minute recess 12b LD array B side minute recess 13 Sphere (positioning member) 14 Heat sink 15 Light reception / light emission Child 16 optical fiber array 17 connecting member

Claims (2)

[Claims] 1. A base substrate having pin guide portions (I) formed on both sides of a surface on which a plurality of wiring circuits are patterned, and a flip-chip mounting method at a predetermined position on the surface of the base substrate. And a plurality of optical fibers are arranged on a surface facing the base substrate, the light receiving / light emitting element having electrodes connected to the wiring circuit patterned, and pin guide portions (II) on both sides thereof. An optical fiber in which the optical axis of the optical fiber is aligned with the optical axis of the light-receiving / light-emitting element by arranging a connecting pin common to the pin guide portion (I) and the pin guide portion (II). In a parallel transmission optical module including an array, minute recesses that make a pair with each other are engraved on the respective facing surfaces of the base substrate and the light receiving / light emitting element, and the minute recesses are positioned in the minute recesses. Interposed member decided to the light receiving /
A parallel transmission optical module in which a light emitting element is mounted on the base substrate. 2. The positioning member is a sphere.
Parallel transmission optical module.