JPH08201660A - Optical coupling module and its manufacture - Google Patents

Abstract

PURPOSE: To precisely optically couple an optical guide such as an optical fiber with an optical element such as a light emitting element at a low cost. CONSTITUTION: A V groove 2 is formed preliminarily on an upper surface of a substrate 1 such as silicon substrate, and the terminal of the optical fiber 3 is fixed, and besides, the light emitting element 4 is fixed on its optical axis, that is, a Z axis at a relatively moderate precision. Then, the V groove 5 is formed on the Z axis so as to be crossed with the Z axis, to put in a spherical lens 6. When the spherical lens 6 is slid along the V grove 5 while operating the light emitting element 4, a light beam is adjusted into an optimum state while surveying the coupling with the optical fiber 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coupling module for connecting a light emitting element or a light receiving element to an optical guide for transmitting light when transmitting and receiving an optical signal.

[0002]

2. Description of the Related Art In an optical communication system or the like, a light emitting element or a light receiving element is used for transmitting and receiving an optical signal. In addition, an optical fiber or an optical waveguide formed on a substrate is used for transmitting an optical signal. For example, when coupling the light emitting element and the optical fiber, the end of the optical fiber is fixed in advance in the V groove or the like so that the height from the upper surface of the substrate coincides with the light emitting position of the light emitting element and faces the end surface of the optical fiber. Thus, the light emitting element is mounted on the substrate. Then, the position of the light emitting element is adjusted and positioned in the two-dimensional direction. In this case, if accurate positioning is not performed, the coupling loss becomes large, and an optical coupling module with sufficient characteristics cannot be obtained. Therefore, conventionally, a method of using an optical microscope for such a positioning process, or reading a mark for positioning and reading this as image data, and performing a position alignment using a pattern recognition technique have been adopted. On the other hand, in order to improve the optical coupling characteristic at the end face of the optical fiber, a method of processing the end face of the optical fiber into a lens shape to widen the aperture angle has been adopted.

[0003]

The conventional optical coupling module and the manufacturing method thereof as described above have the following problems to be solved. Positioning the light emitting element and the like by the optical microscope is a means that depends on the eyes and hands of the human, and variations occur depending on the skill level, and there is a limit to improvement in accuracy.

When pattern recognition is used, an expensive high-performance pattern recognition device is required to read and recognize minute marks. Moreover, since the pattern is recognized by the image processing, the data amount of the image data also increases in order to improve the accuracy. Therefore, it takes a long time to perform the arithmetic processing, and conventionally it takes several tens of seconds to complete the positioning. This increases the mass production cost of this type of module. Also,
Since the light emitting element cannot be operated during the positioning process of the light emitting element, it is not always easy to actually make the optical coupling optimum.

Further, the processing of processing the end surface of the optical fiber into a lens shape is likely to cause some variation, and since one processing step is added, the manufacturing cost is increased. Further, there is a problem in that it is difficult to process such a lens in the optical waveguide and the aperture angle is small, so that sufficient coupling efficiency cannot be obtained. The same problem occurs not only in the coupling between the light emitting element and the optical fiber, but also in the optical coupling between the light receiving element and the optical fiber or the optical waveguide.

[0006]

The present invention adopts the following constitution in order to solve the above points. An optical coupling module of the present invention optically couples a light guide and an optical element on a substrate, and a direction coinciding with an optical axis in the vicinity of a light input / output end face of the light guide is a Z axis. When a direction perpendicular to the Z-axis and perpendicular to the upper surface of the substrate is the Y-axis and a direction perpendicular to the Z-axis and the Y-axis is the X-axis, an optical guide fixed on the upper surface of the substrate with the Z-axis parallel to the upper surface of the substrate And on the Z-axis on the board,
An optical element arranged so that an optical path is directed to the light guide end face, and a V formed on the Z axis between the light guide end face and the optical element in the X axis direction so as to intersect the Z axis on the upper surface of the substrate.
And a spherical lens supported in the groove.

The light guide comprises, for example, an optical fiber,
This optical fiber terminal is supported and fixed in a V groove formed in the Z-axis direction on the upper surface of the substrate, and the optical fiber is positioned in the Y-axis direction with the upper surface of the substrate as a reference surface. The light guide is formed of, for example, an optical waveguide, and the light guide portion is positioned in the Y-axis direction with the upper surface of the substrate as a reference surface. It is preferable that the substrate is made of a silicon substrate and the V groove formed on the upper surface of the substrate is anisotropically etched.

Besides, the position of the light guide in the Y axis direction, the outer diameter of the spherical lens, the positioning accuracy of the optical element in the Y axis direction, and the processing accuracy of the V groove for supporting the spherical lens formed on the upper surface of the substrate. It is recommended to select the same level or higher. Further, a V groove for passing a light beam, which is shallower than the spherical lens supporting surface and oriented in the Z-axis direction, may be formed so as to intersect with the V groove that supports the spherical lens.

The optical element is mounted on the upper surface of the substrate with the light receiving surface facing the light reflecting surface formed at the end of the V groove for passing the light beam which intersects in the Z-axis direction. Composed of chips. The light reflection surface is formed by etching together with the V groove for passing the light beam. The optical element includes a light-receiving element chip and a carrier that supports the light-receiving element so that its light-receiving surface faces the light guide end surface. The light-receiving surface of the light-receiving element is the optical axis position in the Y axis direction on the substrate surface. Is selected sufficiently higher than the optical axis position in the Y-axis direction on the end face of the light guide so that the light beam effective for optical coupling between the light receiving element and the light guide via the spherical lens does not intersect the upper surface of the substrate.

Further, the light output of the light guide for fixing the light emitting element and the light receiving element on the substrate and for guiding the optical signal inputted from the external circuit, and the light output of the light guide for guiding the monitor light branched from the output light of the light emitting element. Both of the end faces are preferably opposed to the light receiving element via the spherical lens.

According to the method of the present invention, when the light guide and the optical element are optically coupled on the substrate, the Z axis is defined as a direction that coincides with the optical axis near the light input / output end face of the light guide.
A direction perpendicular to the Z axis and perpendicular to the upper surface of the substrate is defined as the Y axis, and Z
When the direction perpendicular to the axis and the Y-axis is the X-axis, the light input / output end face of the light guide is fixed to the upper surface of the substrate, and the optical element is arranged so that the optical path is directed to the end face of the light guide on the Z-axis on the substrate. Then, the spherical lens is supported in a V groove formed in the X axis direction on the Z axis between the light guide end face and the optical element so as to intersect the Z axis on the upper surface of the substrate, and the X axis is supported on the V groove. The spherical lens is moved in the direction to optimally select the path of the light beam effective for the optical coupling between the light guide and the optical element, and then the spherical lens is fixed to the V groove.

[0012]

According to the present invention, the V groove is formed in advance on the upper surface of the substrate such as a silicon plate to fix the end of the optical fiber, and the light emitting element is relatively gentle on the optical axis, that is, the Z axis. Will be fixed. Then, a V groove is formed so as to intersect with this on the Z axis, and the spherical lens is housed therein. By sliding the spherical lens along the V-groove while operating the light emitting element, it is possible to adjust to the optimum value while actually measuring the coupling with the optical fiber.

The V groove for supporting the optical fiber on the substrate and the V groove for supporting the spherical lens can be processed in advance with high accuracy. Both the outer diameter of the optical fiber and the outer diameter of the spherical lens can be processed with sufficiently high accuracy. A sufficient accuracy of the light emitting element in the Y-axis direction can be obtained depending on the accuracy of assembling the upper surface of the substrate and the light emitting element. Therefore, the accuracy in the Y-axis direction is originally sufficiently high. On the other hand, there is no problem in adjusting the Z-axis direction with relatively loose accuracy. Here, positioning in the X-axis direction is important,
In the present invention, the positioning of the light emitting element is performed with relatively loose accuracy, and the spherical lens is moved in the X-axis direction to adjust the light beam with high accuracy. It is relatively easy to slide the spherical lens, and since pattern recognition is not necessary, the adjustment time can be shortened.

In the present invention, the light guide means a device such as an optical fiber or an optical waveguide for transmitting light coupled with a light emitting element or a light receiving element. The optical element is a concept including a light receiving element and a light emitting element. Arranging the optical element so that the optical path is directed to the light guide end surface is sufficient if the light guide end surface and the light emitting surface or the light receiving surface of the optical element face each other substantially so as to be optically coupled to each other. It is a concept including a case where the optical path is appropriately turned back by providing.

In the present invention, the upper surface of the substrate serves as a reference surface, and the V groove formed here is mainly for positioning the optical fiber and the spherical lens in the Y-axis direction. Therefore, as long as the portion that contacts the optical fiber or the spherical lens forms a V-shaped valley, the other portion may be processed in any way. The anisotropic etching process refers to automatically and chemically forming a V-groove by utilizing the characteristics of a substrate in which the speed of etching is not isotropic. Further, the light-receiving element chip is an element itself in a bare state which is not mounted on a carrier or the like. In addition, the V-groove for passing the light beam may be substantially V-shaped because the purpose is to pass the light beam.
It can be either letter-shaped or rectangular in cross section.

[Coupling of optical fiber and light emitting element]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a perspective view of an embodiment of the optical coupling module of the present invention. The substrate 1 in the figure is made of a silicon plate used for manufacturing semiconductor applied products and the like. A V groove 2 is formed on the substrate 1 by etching. The terminal of the optical fiber 3 is supported and fixed here. In the present invention, in the end face 3A of the optical fiber 3, the direction that coincides with the optical axis is called the Z axis. Inside the optical fiber 3, the optical signal is transmitted in its longitudinal direction. Therefore, the Z axis is parallel to the upper surface 1A of the substrate and is in the same direction as the V groove 2. The end face 3A of the optical fiber 3 is
It is positioned so as to come to the edge of the groove 7 formed on the substrate 1.

On the other hand, on the Z axis of the substrate 1, a light emitting element 4 is arranged so as to face the end surface 3A of the optical fiber 3. That is, in this example, the light emitting direction of the light emitting element 4 is
The light emitting element 4 is fixed on the substrate 1 so as to face the end face 3A of the optical fiber 3 exactly. In the present invention, this Z
The direction perpendicular to the axis and perpendicular to the substrate upper surface 1A is called the Y axis, and the direction perpendicular to the Z axis and parallel to the substrate upper surface 1A, that is, the direction perpendicular to the Z axis and the Y axis is called the X axis. End face 3A of the optical fiber 3
Another V groove 5 is formed so as to intersect the Z axis between the light emitting element 4 and the light emitting element 4. In this V-shaped groove 5, a spherical lens 6
Initially, it is supported so as to freely roll in the X-axis direction.

When manufacturing the optical coupling module of the present invention,
Using the L-shaped adjusting arm 9 as shown in the figure, the spherical lens 6
Hold down. That is, the adjusting arm 9 first descends in the direction of arrow 11 to press the spherical lens 6 and slides in the direction of arrow 12 to move the spherical lens 6 in the X-axis direction. The spherical lens 6 is rolled as shown by an arrow 13, and the direction of the light beam effective for the optical coupling between the optical fiber 3 and the light emitting element 4 is selected in the optimum state. After that, the spherical lens 6 is fixed on the V groove 5.

The optical coupling module of the present invention having the above structure is housed in a package 15 as shown in FIG. 2, for example. FIG. 2 is an overall view of the optical coupling module of the present invention.
(A) is a plan view and (b) is a side sectional view thereof. As shown in the figure, the package 1 is made of a metal case or the like.
An optical fiber 3 having a coating terminated inside the sleeve 16 is inserted from the left side wall of the optical fiber 5. The end of the optical fiber 3 is supported and fixed in the V groove 2 on the substrate 1 fixed in the center of the package 15. The end of the optical fiber 3 is pressed onto the V groove 2 by a holding plate 17 or the like as shown in the figure.

On the other hand, the light emitting element 4 is fixed so as to face the end surface 3A of the optical fiber 3, and a V groove 5 is formed between them. The spherical lens 6 described above is supported by the V groove 5. A wiring board 18 is fixed to the right side wall of the package 15 so as to penetrate therethrough, and a wiring pattern 19 is formed therein. The wiring pattern 19 and the light emitting element 4 are electrically connected by a bond line or the like (not shown).

[Positioning Accuracy] FIG. 3 is an explanatory view of a method of positioning the light emitting element. The figure is a perspective view of the semiconductor light emitting device,
The state at the time of manufacture is shown in the upper left, and the state when fixed on the substrate is shown in the lower right. That is, the light emitting portion 4A of the light emitting element 4 is formed by stacking semiconductor films as in the case of manufacturing a transistor, an integrated circuit, or the like. Therefore, in the main body having a thickness of about 100 μm in the Y-axis direction in the drawing, for example, 5 μm from the surface
The light emitting portion 4A is formed at a depth of about m. And FIG.
On the substrate 1 shown in FIG. 3, the optical fiber 3 is turned over so that the optical axis can be easily aligned with the optical fiber 3 when viewed in the Y-axis direction, and the light emitting portion 4A is arranged at a position close to the upper surface of the substrate as shown in the lower right of FIG. To do. The position of the light emitting portion 4A in the Y-axis direction can be controlled with high accuracy by a semiconductor process.

For example, in the case of the optical coupling module as shown in FIG. 1, assuming that the spherical lens 6 is not provided, the light emitting element 4 is aligned by ± 0.5 in both the Y-axis direction and the X-axis direction.
An accuracy of about μm is required. An accuracy of about ± 5 μm is sufficient in the Z-axis direction. Since the light emitting element 4 as shown in FIG. 3 is formed by a semiconductor process, it is possible to control the position of the light emitting portion 4A in the Y axis direction with an accuracy of about 0.5 μm.

On the other hand, when the end of the optical fiber 3 shown in FIG. 1 is supported and fixed to the V groove 2 on the substrate 1, the same degree of accuracy can be achieved relatively easily. In this case, for example, a highly accurate mask is formed on the substrate 1 by using a photolithography process,
Etching is performed with an alkaline etching solution. At this time, it is possible to form the V groove having a constant etching angle and a high precision width due to the dependency of the crystal plane orientation of silicon. In the present invention, this method is called anisotropic etching processing. That is, if a mask having a window corresponding to the width and length of the V groove is used, the V groove having a constant and high precision is automatically formed by etching.

FIG. 4 shows a cross-sectional explanatory view of the V groove. This V
The groove is formed by anisotropic etching, and as shown in the figure, the angle between the side surfaces of the valley is 70.52 °. If an optical fiber with a circular cross section is housed here,
For example, if the radius is R and the width of the V groove is W, the height h of the core C of the optical fiber from the upper surface 1A of the substrate is as shown by the formula in this figure. Optical fiber outer diameter accuracy is usually ±
It is about 1 μm. Since the accuracy of the V groove can be set with higher accuracy, the positional accuracy of the core C of the optical fiber from the upper surface 1A of the substrate can be substantially selected with the same level of accuracy as the positioning of the light emitting element in the Y-axis direction. The same applies when a spherical lens is housed in the V groove instead of the optical fiber.

From the above, the optical fiber 1 shown in FIG.
Or the positioning accuracy of the light emitting element 4 in the Y-axis direction is required ±
No particularly complicated adjustments are required to set the thickness to about 0.5 μm. The same applies to the spherical lens 6. On the other hand, the positioning of the light emitting element 4 in the X-axis direction shown in FIG. Specifically, the level may be about ± 50 μm. Then, the spherical lens 6 is moved to X by the adjusting arm 9 described above.
Optimizing the direction of the light beam by moving it in the axial direction. Further, since these processes are performed with the substrate upper surface 1A as a reference, it is most preferable to use the substrate upper surface 1A as a reference surface.

[V-groove in Z-axis direction] FIG. 5 shows a coupling state diagram of the light emitting element and the optical fiber. (A) is its plan view,
FIG. 3B is a side sectional view of a main part of the module cut along a plane passing through the Z axis and the Y axis. In the embodiment shown in FIG. 10A, the core 3C of the optical fiber 3 and the light emitting element 4 are positioned so as to be coupled to the core 3C. In this embodiment, FIG.
In addition to the above embodiment, a V groove 22 for passing a light beam in the Z-axis direction is newly provided. As shown in (b) of the figure, the position of the core 3C of the optical fiber 3 is very close to the upper surface 1A of the substrate. Therefore, a shallow V groove 22 is formed in the Z-axis direction so as not to interfere with the light beam 23 reaching the optical fiber 3 from the optical element 4. The V groove 22 is shallower than the V groove 5 supporting the spherical lens 6, and is formed so as to intersect with the V groove 5. Therefore, the spherical lens 6 is X
When moving in the axial direction, the outer peripheral surface of the spherical lens 6 is always in contact with the wall surface of the V groove 5, and is not affected by the V groove 22. Since the V groove 22 for passing the light beam is not required to have high positioning accuracy, sandblasting, etc.
A suitable processing method can be adopted.

In the present invention, as shown in FIG. 5 (a), the positioning accuracy of the light emitting element 4 is made relatively gentle, and instead, the spherical lens 6 is formed on the V groove 5 by the arrow 1.
By moving in two directions, the light beam 23 emitted from the light emitting element 4 is accurately guided to the core 3C of the optical fiber 3. The optimum value in this case is selected by monitoring the output light of the optical fiber 3 while the light emitting element 4 is actually operating. This is an effect peculiar to the present invention in which the light emitting element 4 can be positioned and fixed on the substrate 1 and the final adjustment can be performed after the wiring is completed. At this time, as shown in the drawing, the height of the spherical lens 6 in the Y-axis direction and the position in the Z-axis direction are determined by the V groove 5
Are positioned more accurately, and the path of the light beam 23 is adjusted by moving only the position in the X-axis direction. Therefore, it is necessary to select the positioning accuracy of the light-emitting element 4 in the X-axis direction, which is a drawback of the related art, to be sufficiently loose. To enable.

[Optical Waveguide and Light-Emitting Element] FIG. 6 shows an overall view of an optical coupling module using the optical waveguide. (A) is the top view, (b) is the sectional side view. In the illustrated embodiment, the end face of the optical fiber 3 is supported and fixed on the substrate 1 by the left side portion of the package 15, and the optical waveguide 21 is formed in the central portion. That is, the optical waveguide 21 formed by the semiconductor process on the upper surface of the substrate 1 is connected to the optical fiber 3 and the light emitting element 4.
It is placed between and. Except for this part, there is no difference from the embodiment of FIG. Therefore, the same parts as those in FIG. 2 are designated by the same reference numerals, and the duplicated description will be omitted.

As shown in this figure, the end face 21A of the optical waveguide 21 is directed to the light emitting element 4 side, and the optical fiber 3 is just provided.
The light guide portion 21B is arranged so as to be coupled to the terminal. In this way, when the optical waveguide is formed on the upper surface of the substrate 1 by the semiconductor process, the positioning accuracy of the light guide path 21B can be selected at the same level as the semiconductor processing accuracy. In this case, when the portion corresponding to the clad of the optical fiber, the light guide portion 21B, and the portion corresponding to the clad covering the optical fiber are further sequentially formed on the substrate 1, the position of the light guide portion 21B is located on the upper surface of the substrate. With reference to the height of the thickness of the lower clad. The accuracy of the thickness of the clad is within ± 1 μm, and the light guide portion 21B can be formed at the same level as the accuracy of the fiber. When performing optical coupling with this and the light emitting element 4 described above, for example, the following conditions are set.

FIG. 7 is an explanatory view of an optical path between the light emitting element and the optical waveguide. For example, as shown in this figure, it is assumed that the light guide portion 21B of the optical waveguide 21 is positioned just above the upper surface of the substrate 1 at a height h corresponding to the thickness of the lower clad.
In this case, the light emitting portion of the light emitting element 4 is located very close to the upper surface of the substrate 1. Therefore, the light beam advances slightly obliquely from the light emitting element 4 as shown in the figure. In order to set such a direction of the light beam, the center position of the spherical lens 6 is obtained by the arithmetic expression shown in the figure. That is,
The distance from the light emitting element 4 to the center of the spherical lens 6 is L1,
When the distance from the center of the spherical lens 6 to the end face 21A of the optical waveguide 21 is L2, the height k of the spherical lens 6 from the upper surface of the substrate 1 is calculated as h × L1 / (L1 + L2). The V groove 5 that supports and fixes the spherical lens 6 is molded under such conditions. Unlike the conventional method of directly coupling the optical waveguide and the optical element, there is no problem in coupling even with such a step.

Also in this case, since the spherical lens 6 can be slid on the V groove 5 to adjust the light beam,
It is sufficient to select the positioning accuracy of the light emitting element 4 within about ± 50 μm in the X-axis direction. In addition, in the embodiments of FIGS. 1, 2, 5, and 6, the length of the V groove 5 is 100 in the X direction.
It is sufficient to select so that the spherical lens 6 can be moved by about μm. After the optimization adjustment is performed using the adjustment arm 9 shown in FIG. 1 and the optimum position of the spherical lens 6 is determined, the spherical lens 6 is fixed to the V groove 5 with an adhesive or the like in that state. Since the accuracy in the Z-axis direction between the optical fiber and the spherical lens may be about ± 50 μm, the end face 3A of the optical fiber 3 can be easily abutted against the wall surface of the groove 7 on the substrate 1 shown in FIG. Predetermined accuracy can be achieved. For the positioning of the light emitting element 4, it is possible to use positioning with a microscope using a marker or the like, or a very simple pattern recognition device with low accuracy.

Since the position of the spherical lens 6 can be adjusted in about 1 or 2 seconds, the optimum conditions can be set in a sufficiently shorter time than in the conventional case. Of course, it is not necessary to process the spherical lens on the end face of the optical fiber or the like. Positioning of the optical fiber in the Y-axis direction can be selected by the depth of the V groove. Therefore, as shown in FIG. 5B, when viewed in the Y-axis direction, the core position can be selected at the same height as the light emitting element. However, it is difficult to match the height of the light guide portion with the height of the light emitting portion of the light emitting element because the cladding layer, the light guide portion, and the like are sequentially formed on the substrate surface of the optical waveguide. Therefore, FIG.
It is also necessary to adjust the light beam in the height direction as shown in.

It should be noted that the spherical lens always acts as an optical lens having a constant property no matter how it is rolled on the V groove or from any direction, and has no directivity. Moreover, it can be processed with higher accuracy than a general disc-shaped lens. The processing accuracy is about ± 1 μm, and the manufacturing can be performed with the same accuracy as the outer diameter accuracy of the optical fiber. Therefore, it can be said that it is optimal for precise optical axis control of the final light beam as in the present invention. In particular, for the optical coupling between the light emitting element and the optical waveguide whose positions in the Y-axis direction are greatly different on the substrate, optimal coupling can be easily performed by using such a spherical lens as shown in FIG. Actually, even if there is a difference in height of about several tens of μm, absorption is possible sufficiently. In this case, the light beam has an inclination of about 2 to 3 °, but the characteristics are hardly affected. For this reason, there is an effect that complicated processing associated with alignment in the Y-axis direction becomes unnecessary.

[Coupling with light receiving element] In the above embodiment,
Although the embodiment relating to the optical coupling between the light emitting element and the optical fiber or the optical waveguide has been described, the present invention can be applied to the coupling between the light receiving element and these light guides. FIG. 8 shows a coupling state diagram (part 1) of the light receiving element and the optical fiber. The configurations of the optical fiber 3, the V groove 5, the spherical lens 6, the V groove 22 and the like shown in the figure are almost the same as those shown in FIG. A light receiving element chip 31 is mounted on the right end of the shallow V groove 22 formed in the Z-axis direction so that the light receiving surface faces the direction of the V groove 22. The light receiving element chip 31
The electrode is directly soldered and fixed to the wiring pattern 33 formed on the substrate. Also in such an optical coupling module, the spherical lens 6 is formed on the V groove 5 in the direction of arrow 12,
That is, the coupling state is optimally selected by moving in the X-axis direction.

As shown in (b), the light beam 23
Reaches the light reflecting surface 22A formed at the end of the V groove 22 from the optical fiber 3 through the spherical lens 6 along the V groove 22 in the Z axis direction. Here, the light beam 23 is reflected obliquely in the upper left direction and reaches the light receiving surface of the light receiving element chip 31. The above-mentioned structure is adopted because the light-receiving element chip 31 having a light-receiving surface on the surface on which the electrodes for attaching the solder balls 32 are provided is used and is fixed directly on the substrate 1. . Usually, the light-receiving element chip 31 is mounted on a carrier having an appropriate size for mechanical protection and lead wire drawing. However, in this example, since the light-receiving element chip 31 is directly fixed on the substrate 1 via the solder balls 32 without such a carrier, the light-receiving portion can be sufficiently miniaturized, and the carrier becomes unnecessary, which results in cost reduction. It can be significantly reduced. Further, since the wiring pattern 33 is directly soldered, there is an advantage that a bond line or the like is unnecessary. If this reflecting surface is formed by etching together with the V groove 22 for passing the light beam, it is possible to collectively perform the forming process in one step.

On the other hand, when the package has a sufficient margin, the light receiving element mounted on the carrier is fixed on the substrate. FIG. 9 shows a coupling state diagram (part 2) of such a light receiving element and an optical fiber. The configurations of the optical fiber 3, the V groove 5, the V groove 22, the spherical lens 6 and the like shown in the figure are exactly the same as those shown in FIG. On the other hand, the light receiving element chip 31 is the carrier 3 made of silicon as shown in the figure.
4 and is positioned at the right end portion of the V groove 22. A wiring pattern 35 is provided on the carrier 34, and the light-receiving element chip 31 is soldered and connected on an extension line of the wiring pattern 35. The wiring pattern 35 is electrically connected to the wiring board 18 shown in FIG. 2 by a bond line or the like.
In this case, the carrier 34 positions the light-receiving element chip 31 at a sufficiently high position on the substrate 1. Therefore,
For example, if the position of the core 3C of the optical fiber 3 is selected to be a sufficiently high position, the V groove 22 along the Z-axis direction becomes unnecessary. Therefore, there is an effect that the configuration of the substrate itself is simplified.

[Applied Product] The optical coupling module of the present invention is put into practical use, for example, in the following form. In FIG.
The optical coupling module Example top view is shown. In this embodiment, the optical fiber core 44-1 is connected to the package 40. The optical fiber core 44-1 is the package 4
Inside 0, it is connected to the waveguide 43-1 formed on the substrate 41. Further, the waveguide 43-1 is divided into two by the coupler 45 into the waveguides 43-2 and 43-3, and the waveguide 43-2 faces the light emitting element 51 and is optically coupled in the manner described above. That is, a V groove 48 for passing a light beam is formed in the Z axis direction between the light emitting element 51 and the waveguide 43-2, and a V groove 46 is further formed in the X axis direction. And that V
The spherical lens 47 is supported in the groove 46, and the optimization of the light beam described above is performed.

A light receiving element 52 is provided so as to receive the light output from the back surface of the light emitting element 51 in order to monitor the output light of the light emitting element 51. This is carrier 5
3 is mounted, and its output is taken out to an external circuit. The light receiving element 52 monitors the output of the light emitting element 51, and performs stabilization control of the output level of the light emitting element 51. Further, a light receiving element 54 is provided at the center of the right end of the substrate 41 to receive the optical signal guided by the waveguide 43-3. The optical coupling between the light receiving element 54 and the waveguide 43-3 is performed by the spherical lens 50 on the V groove 49 formed in the X axis direction.
Optimized by. The light receiving element 54 is mounted on a carrier 55, and the output thereof is guided to a preamplifier 56, amplified, and then taken out to an external circuit. A wiring board 57 is provided so as to penetrate a side wall of the package 40 shown on the right side of the drawing, and a wiring pattern 58 is formed therein. Such a configuration is similar to that of the embodiment already described.

With the above configuration, the light emitting element 51 transmits a constant signal to the waveguide 43-2, and conversely the waveguide 43-3 and the light receiving element 54 receive an optical signal. You can In addition, FIG.
The waveguide 43-3, the light receiving element 54, and the spherical lens 50.
It is a longitudinal cross-sectional view showing the relationship with. Further, (b) is a vertical cross-sectional view showing the relationship between the waveguide 43-2, the light emitting element 51, the spherical lens 47, and the like. Further, (c) shows the optical fiber 44.
Terminal cap 4 for guiding -1 through the package 40
2 and the holding plate 6 for fixing the end of the optical fiber on the substrate 41
It is a sectional view of a portion such as 0.

FIG. 12 is a plan view (No. 2) of the embodiment of the optical coupling module. In this embodiment, the same parts as those in FIG. 10 are designated by the same reference numerals. The difference between this embodiment and the embodiment of FIG. 10 is that the output light of the light emitting element 51 is monitored by the light receiving element 54. That is, in this example, one light receiving element 5
Reference numeral 4 serves to both receive a signal and monitor the output light of the light emitting element 51. Therefore, the output light of the light emitting element 51 is branched by the coupler 45-3 into the waveguide 43-2 and the monitoring waveguide 43-5. The output of the waveguide 43-5 is guided to the front of the spherical lens 50.
This light is incident on the light receiving element 54.

A light guide such as an optical fiber generally transmits an optical signal bidirectionally. Therefore, as shown in this figure, the light transmitted through the optical fiber 44-1 is received by using the waveguide 43-3, while the optical signal is transmitted in the opposite direction through the waveguide 43-2. . At this time, if a so-called ping-pong transmission method is used, transmission / reception timings are shifted from each other, and an optical signal is not received from the waveguide 43-3 while the light emitting element 51 is emitting light. On the other hand, the light emitting element 51 stops operating while the optical signal is received from the waveguide 43-3. In this way, since transmission and reception are performed with a time shift, respectively, when the signal is just received via the waveguide 43-3, the light receiving element 54 receives the optical signal for communication. The optical signal output from the light emitting element 51 can be received through the waveguide 43-5 and monitored while the signal is at rest. Due to such a relationship, if one light receiving element 54 is mounted, the monitor for stabilizing the transmission signal and the receiving operation can be used in common, and the substrate can be downsized and the cost can be reduced. Also in this embodiment, since the light beam can be guided to the light receiving element 54 by using the spherical lens 50 in an appropriate and appropriate state, the waveguide 43-3 positions and fixes the end faces of the waveguide 43-4 independently. It is possible to sufficiently simplify the adjustment and reduce the cost as compared with the case of performing.

The present invention is not limited to the above embodiments. In the above embodiments, the substrate is a silicon plate and the V groove is formed by anisotropic etching. However, any substrate can be used as long as it can process the V groove with the same accuracy. Good. Further, the outer diameter of the optical fiber, the outer diameter of the spherical lens, and the positioning accuracy of the optical element, that is, the light emitting element or the light receiving element in the Y-axis direction are substantially the same level as the processing accuracy of the V groove for supporting the spherical lens formed on the upper surface of the substrate. If selected, the above configuration is achieved. Of course, as long as either of them can be machined with a higher accuracy than that, it will not hurt. Therefore, the processing accuracy is preferably at least the same level or higher. In addition, the configuration of the module itself may be replaced with a configuration widely used in optical semiconductor modules and other circuits.

[0043]

The optical coupling module of the present invention described above is an optical guide having an optical input / output end face fixed to the upper surface of a substrate and an optical element arranged so that the optical path is directed to the end face of the optical guide on the Z axis on the substrate. And a spherical lens supported by a V groove formed in the X-axis direction so as to intersect with the Z-axis. Therefore, by moving the spherical lens along the X-axis, the optical element moves in the X-axis direction. Even if the positioning accuracy of is set to be sufficiently loose, optimal coupling conditions can be obtained. Moreover,
Optimum conditions can be selected by moving the spherical lens while the optical element is operating, and adjustment can be made in a sufficiently short time compared to conventional positioning processing, so it is possible to reduce the cost and improve the characteristics of the device in the mass production process. .

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of an optical coupling module of the present invention.

FIG. 2 is an overall view of the optical coupling module of the present invention.

FIG. 3 is an explanatory diagram of a light emitting element positioning method.

FIG. 4 is a cross-sectional explanatory view of a V groove.

FIG. 5 is a connection state diagram with a light emitting element.

FIG. 6 is an overall view of an optical coupling module using an optical waveguide.

FIG. 7 is an explanatory diagram of an optical path between a light emitting element and an optical waveguide.

FIG. 8 is a coupling state diagram (No. 1) with a light receiving element.

FIG. 9 is a coupling state diagram (No. 2) with the light receiving element.

FIG. 10 is a plan view (No. 1) of the embodiment of the optical coupling module.

FIG. 11 is a side sectional view of a main part of an optical coupling module.

FIG. 12 is a plan view (No. 2) of the embodiment of the optical coupling module.

[Explanation of symbols]

 1 substrate 1A substrate upper surface 2 V groove 3 optical fiber 3A end face of optical fiber 4 light emitting element 5 V groove 6 spherical lens 9 adjusting arm

Claims (11)

[Claims] 1. A device for optically coupling a light guide and an optical element on a substrate, wherein a direction coinciding with an optical axis in the vicinity of a light input / output end face of the light guide is defined as a Z axis. The direction perpendicular to the upper surface of the substrate and perpendicular to the upper surface of the substrate is the Y-axis, and the direction perpendicular to the Z-axis and the Y-axis is X.
When used as an axis, an optical guide having the Z axis fixed to the upper surface of the substrate parallel to the upper surface of the substrate, and an optical element arranged so that an optical path is directed to the end surface of the light guide on the Z axis on the substrate. An element, and a spherical lens supported on a V groove formed in the X axis direction on the Z axis between the light guide end surface and the optical element so as to intersect the Z axis on the upper surface of the substrate. An optical coupling module comprising: 2. The light guide comprises an optical fiber,
The optical fiber terminal is supported and fixed in a V groove formed in the Z-axis direction on the upper surface of the substrate, and the optical fiber is positioned in the Y-axis direction with the upper surface of the substrate as a reference surface. Item 2. The optical coupling module according to item 1. 3. The optical coupling module according to claim 1, wherein the light guide comprises an optical waveguide, and the light guide portion is positioned in the Y-axis direction with the upper surface of the substrate as a reference surface. 4. The substrate is made of a silicon substrate, and the V groove formed on the upper surface of the substrate is positioned in the Y-axis direction by anisotropic etching processing. The optical coupling module according to 1. 5. The position of the light guide in the Y-axis direction, the outer diameter of the spherical lens, and the positioning accuracy of the optical element in the Y-axis direction are defined by a V-shaped groove for supporting the spherical lens formed on the upper surface of the substrate. The optical coupling module according to claim 4, wherein the optical coupling module is selected to have substantially the same level of processing accuracy or higher. 6. A V-shaped groove for passing a light beam, which is shallower than a spherical lens supporting surface and is oriented in the Z-axis direction, is formed so as to intersect with the V-shaped groove for supporting the spherical lens. Item 6. The optical coupling module according to items 1 to 5. 7. The optical element faces the upper surface of the substrate with its light-receiving surface facing the light-reflecting surface formed at the end of a V-shaped groove for passing a light beam that intersects the Z-axis direction. 7. The optical coupling module according to claim 6, comprising a light-receiving element chip mounted. 8. The optical coupling module according to claim 7, wherein the light reflection surface is formed by etching together with the V groove for passing the light beam. 9. The optical element comprises a light-receiving element chip and a carrier that supports the light-receiving element so that its light-receiving surface faces the light guide end surface. The optical axis position in the axial direction is the optical axis position in the Y-axis direction on the end surface of the light guide so that a light beam effective for optical coupling between the light receiving element and the light guide that passes through the spherical lens does not intersect the upper surface of the substrate. The optical coupling module according to claim 1, wherein the optical coupling module is selected sufficiently higher. 10. A light guide for fixing a light emitting element and a light receiving element on the substrate and guiding an optical signal input from an external circuit, and an optical guide for guiding monitor light obtained by branching output light of the light emitting element. The optical coupling module according to claim 1, wherein both of the light output end faces are opposed to the light receiving element via the spherical lens. 11. When optically coupling a light guide and an optical element on a substrate, a direction coinciding with the optical axis in the vicinity of the light input / output end face of the light guide is defined as a Z axis, and is perpendicular to the Z axis. And the direction perpendicular to the upper surface of the substrate is the Y-axis, and the direction perpendicular to the Z-axis and the Y-axis is X-axis.
When the optical axis is an axis, the light input / output end face of the light guide is fixed to the upper surface of the substrate, and an optical element is arranged on the Z axis on the substrate so that an optical path is directed to the light guide end face. On the Z axis between the optical element and the optical element, the spherical lens is supported in a V groove formed in the X axis direction on the upper surface of the substrate so as to intersect the Z axis, and the X axis is supported on the V groove. Optical coupling characterized in that the spherical lens is fixed in the V-groove after the spherical lens is moved in the direction to optimally select the path of the light beam effective for optical coupling between the light guide and the optical element. Module manufacturing method.