JPH01261604A - Optical coupler - Google Patents

Abstract

PURPOSE:To easily realize low-loss optical coupling between an optical waveguide and optical fibers by finishing at least part of the waveguide-side end faces of the optical fibers to have oblique faces. CONSTITUTION:V-grooves 6-8 are formed on a crystal base plate 1, on which an optical circuit constituted of optical waveguides 3-5 is formed by a crystal anisotropic etching process and optical fibers 9, 11, 13 respectively provided with obliquely finished faces at, at least, part of the waveguide-side end faces are optically coupled with the waveguides 3-5 by closely putting the fibers 9, 11, and 13 in the grooves 6-8. Since the V-grooves 6-8 are formed monolithically on the base plate 1, necessity of complicated optical axis adjustment is eliminated and, moreover, since the crystal anisotropic etching process applied to the grooves 6-8 can be carried out collectively on the plural grooves with an inexpensive device, the productivity and economical efficiency of this optical coupler are improved. In addition, since the end faces of the optical fibers 9, 11, and 13 are finished to have the oblique faces, the end faces of the optical fibers 9, 11, and 13 can be brought nearer to the optical waveguide to prescribed intervals. Thus low-loss optical coupling can be realized between the waveguides 3-5 and fibers 9, 11, and 13.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an optical coupling device for optically coupling an optical waveguide and an optical fiber, and particularly to an optical coupling device suitable for easily performing low-loss optical coupling. Regarding equipment.

[Conventional technology]

The following techniques are known for conventional optical coupling devices.

(1) Separately from the substrate on which the optical waveguide is formed, prepare a Si plate in which a V-groove is formed by crystal anisotropic etching,
The optical fiber is supported by this groove and optically coupled to the optical waveguide (Japanese Patent Laid-Open No. 60-95410, etc.).

(2) A rectangular groove is formed on the optical waveguide substrate by reactive dry etching, and an optical fiber is installed in the rectangular groove to perform optical coupling between the leading waveguide and the optical fiber. (Unexamined Japanese Patent Publication No. 56-146107, etc.).

(3) GaAq or I n P with a leading wavepath formed
A (1) groove is formed on a manufactured substrate (crystal plane orientation (100)) by ion beam dry etching, and an optical fiber is installed in this V groove (Japanese Patent Laid-Open No. 60-83006, etc.).

(4) A V-groove with a (111) crystal plane is formed by crystal anisotropic etching on the Si crystal substrate (crystal plane orientation (100)) on which a leading waveguide is formed, and an optical fiber is inserted into this V-groove. (Japanese Patent Application Laid-Open No. 61-267010, etc.).

[The invention tries to solve ii! Problem) The above conventional technology (1) requires complicated optical axis adjustment in order to optically couple the leading waveguide and the optical fiber, and therefore has a problem in terms of productivity.

The prior art (2) above differs from the technology (1) in that seven rectangular grooves are formed on the optical waveguide substrate. Therefore, there is no need to particularly adjust the optical axis, and optical coupling can be achieved simply by installing the optical fiber in the rectangular groove. However, since the shape of the groove is rectangular, the position of the optical fiber cannot be determined uniquely, and there is a problem that the optical coupling efficiency varies due to the error between the width of the groove and the outer diameter of the optical fiber.

Since the prior art (3) above uses a V-groove, the position of the optical fiber is uniquely determined, and variations in optical coupling efficiency as in the technology (2) do not occur. However, since the groove processing method is dry etching, an expensive vacuum device is required, which is a heavy economic burden.

Further, in order to install an optical fiber with an outer diameter of 125 .mu.m inside the shell, the depth of the (1) groove is about 100 .mu.m, but dry etching takes several tens of hours to process one groove of about 100 .mu.m. Therefore, there was a problem in terms of productivity.

In the prior art (4) above, since the V-groove is monolithically formed on the guiding waveguide substrate, there is no need for optical axis adjustment. Moreover, since it is a groove, the position of the optical fiber is uniquely determined. (2) Since the grooves are processed by crystal anisotropic wet etching, it is economical to use an inexpensive constant-temperature solution bath as the processing equipment.

In addition, even if there are multiple grooves, it can be processed all at once, resulting in good productivity.

However, although the technique (4) has many advantages, it has a fatal drawback. This will be explained with reference to FIG. In FIG. 14, an optical waveguide 201 and a crystal plane orientation (100) are placed on a Si substrate 20 (crystal plane orientation (100)).
11) A V-groove 202 consisting of a plane is monolithically formed.

In the technique (4), since the VR 202 is processed by crystal anisotropic etching, the crystal 203 consisting of the crystal plane orientation (111) is also formed at the same time as the ViN 202. When the optical fiber 204 is installed in the V-groove 202, the end face of the optical fiber 204 collides with the surface 203, so this surface 203
There was a problem in that the optical fiber 204 could not be brought close to the leading waveguide 201 due to the obstruction. When using a commercially available optical fiber with an outer diameter of 125 μm, the optical waveguide 201
The distance d between the end face of the optical fiber 204 and the end face of the optical fiber 204 is about 40 μm.
It is not possible to perform low-loss optical coupling between the two.

As mentioned above, conventional optical coupling devices have low productivity.

There were problems in terms of economy and optical coupling efficiency.

An object of the present invention is to provide an optical coupling device that can easily perform low-loss optical coupling between an optical waveguide and an optical fiber.

[Means to solve the problem]

The above purpose is to form a V-groove by crystal anisotropic etching on a crystal substrate on which an optical circuit having an optical waveguide as a coupled element is formed, and at least part of the light from the end surface of the photosensitive waveguide is formed in this V-groove. This is achieved by placing obliquely processed optical fibers closely together and optically coupling the optical waveguide and the optical fiber.

[Effect]

Since the groove is monolithically formed on the optical waveguide substrate, there is no need for complicated optical axis adjustment.

Crystal anisotropic etching is highly productive and economical because multiple V-grooves can be processed at once using inexpensive equipment.

Since the end face of the optical fiber is processed diagonally, the 14th
The end face of the optical fiber 204 no longer collides with the plane 203 in the figure, making it possible to bring the end faces of the optical waveguide and the optical fiber close to each other to a predetermined distance. That is, low-loss optical coupling between the guide waveguide and the optical fiber can be realized.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of an optical coupling device according to a first embodiment of the present invention. Further, FIG. 2 is a partially enlarged side view of the vicinity of the V-groove 8 in FIG. 1.

In FIG. 1, a substrate 1 is monolithically formed with an optical circuit 2 consisting of an optical waveguide shown by a solid line in the drawing, and grooves 6, 7.8. Optical fiber 9.11. ．． 13 are placed 8 in close contact with the V-grooves 6, 7.8, respectively, and are optically coupled to the optical waveguides 3, 4.5 at the ends of the optical circuit 2. A portion of the end surfaces of the optical waveguides 3, 4, and 5 of the optical fibers 9, 11, and 13 are each processed to be oblique as shown at 10 degrees per side.

The substrate 1 is a Si single crystal substrate with a (100) crystal plane orientation. The thickness used was 300 μm.

The optical circuit 2 is an optical multiplexing/demultiplexing device that is an integrated combination of three three-dimensional optical waveguide type directional couplers. Optical multiplexing/demultiplexing devices are essential devices in optical wavelength division multiplexing communications in optical subscriber networks. The dimensions of the element part are width 1
The length was 40 meters. A wavelength of 1.3 μm and 1.
When two lights with a wavelength of 55 μm propagate through the optical fiber 9 and enter the optical waveguide 3, these lights are wavelength-separated by the optical circuit 2, and the light with a wavelength of 1.3 μm passes through the leading waveguide 4 and is transmitted to the optical fiber 11. , light with a wavelength of 1.55 μm is transmitted through the optical waveguide 5 to the optical fiber 13.

Conversely, light with a wavelength of 1.3 μm enters the optical waveguide 4 from the optical fiber 11, and light with a wavelength of 1.55 μm enters the optical fiber 13.
These lights are wavelength-combined by the optical circuit 2, and then pass through the optical waveguide 3 to the optical fiber 9
It is transmitted to

The optical waveguides (optical waveguides 3, 4 and 5) constituting the optical circuit 2 are single mode waveguides made of silica glass. The cross section of the core is 10 μm wide x 8 μm high, the thickness of the cladding layer is 10 μm, and the relative refractive index difference Δn between the core and cladding is 0.25.
%. The propagation loss was 0.1 dB/m. The end faces of the optical waveguides 3, 4.5 are etched vertically.

■ Grooves 6, 7.8 are composed of planes with crystal plane orientation (111), and the groove direction is (110>). ■ The abutting plane of groove 6° 7.8 (plane 15 in Figure 2) is also a crystal plane. The plane direction is (111)
The ■grooves 6, 7.8 were collectively machined as follows. First, a 5-ins film is formed on the substrate 1 by thermal oxidation. This SiOz film is patterned into lines by photolithography. Using the patterned 5iOz film as an etching mask, KOH40w
About 5% Si in a t% aqueous solution (constant temperature solution M at 60°C)
Time etching. Since the etching rate of the (111) plane is the slowest, the (1,11) plane remains, and the final V-groove 6 has a groove angle of 70.5°, a depth of 94.3 μm, and a length of 11.
7 and 8 were obtained. The processing accuracy was ±0.2μm.
The angle of surface 15 (θ in FIG. 2) was 54.7''.

The optical fibers 9, 11, and 13 are silica-based single mode optical fibers. The outer diameter is 125 μm, the diameter is 9 μm, and the spot size is 5 μm. The end faces of optical fibers 9, 11, and 13 were ground obliquely at points 10, 12, and 14.

During processing, the processing speed is set to WALLL to prevent the end face of optical fiber 9.11.13 from cracking. The end surfaces other than surfaces 10, 12, and 14 are polished perpendicular to the optical axis. What is the grinding angle?

In order to prevent the end faces of the optical fibers 9, 11, 13 from colliding with the abutting surfaces of the V-grooves 6, 7°8 (surface 15 in FIG. 2), the angle was set to be larger than l1l=54.76. Then 1
0,12.14 is 10 μm away from the center of the optical fiber 9°11.13.

(2) If the optical fibers 9, 11 and 13 processed as described above are installed in close contact with the grooves 6, 7, and 8.

Optical axes of optical fibers 9, 11.13 and optical waveguide 3°4.5
Since the optical axes of the two coincide with each other with an accuracy of ±0.5 μm (dotted chain line in Figure 2), there is no need to adjust the optical axis.
End face 10, 1.2.1 of optical fiber 9, 11.13
Since it is machined as shown in 4, it does not collide with the abutting surface of V16, 7, and 8 (surface 15 in Figure 2).
Optical waveguide 3° 4.5 core and optical fiber 9, 1.1.1
The core of No. 3 can be directly end-face connected (coupling portion 16 in FIG. 2). The optical coupling loss at this time was 1 dB.

According to the first embodiment, the optical fibers 9 and 11°13 are connected to V
By simply placing the optical waveguides 3, 4, 5 in close contact with the grooves 6, 7.8, the optical fibers 9° 11.13 could be optically coupled with a coupling loss as low as 1 dB. That is, low-loss optical coupling can be easily achieved without adjusting the optical axis, which has the effect of improving productivity. Multiple V-grooves can be processed all at once in an inexpensive constant temperature solution bath.

It is advantageous in terms of productivity and economy.

In addition, in order to perform optical coupling with even lower loss, this
Leading waveguides 3, 4.5 and optical fibers 9.11, 1 of the embodiment
When anti-reflection coating was applied to the end face of No. 3, the optical coupling loss was improved to 0.8 dB.

In addition, optical waveguides 3, 4.5 and optical fibers 9, 11° 13
When the end faces of the core are bonded together using an ultraviolet curable resin with a refractive index equal to the core's refractive index, the optical coupling loss is 0.6 dB.
is obtained. Guide wavepaths 3, 4.5 and optical fibers 9,
A carbon dioxide laser is irradiated to the end face joint part (joint part 16) of 11.13, and the optical waveguide 3°4.5 and the optical fibers 9 and 11 are connected.
．． When 13 is glass fused, 0.5 dB
A very low optical coupling loss can be obtained, and the improvement effect is remarkable.

In addition, in order to maintain the stability of optical coupling loss, the optical fiber 9
, 11.13 and the surfaces of the V-grooves 6, 7.8, the optical fibers 9, 11, 1.3 are connected to the V-grooves 6, 7.8, respectively.
7.8 was fixed with solder. After fixation, a temperature cycle test (-45 to 80°C) was conducted, but no detectable change in optical coupling loss was observed.

Next, a second embodiment of the present invention will be described using FIG. 3. FIG. 3 is a perspective view of an optical coupling device according to a second embodiment of the present invention.

In FIG. 3, an optical circuit 21 is formed on a substrate 20. The optical circuit 21 includes four optical waveguides 22°23.24,
This is a complete lattice type 4×4 optical switch circuit in which 25 and four leading wave paths 26 and 27°28.29 intersect with each other. The leading wavepaths 22, 23, 24° 25, 26, 27, 28, 29 are optical fibers 31, 32, 33, 34, 36, respectively.
It is optically coupled to 37°38.39. The optical fibers 31° 32. 33, 34, 36, 37, 38, 39 are connected to the substrate 2.
0 (not visible in the shadow of the optical fiber in Fig. 3). Tape type 4-core optical fiber 3
0.35 is the optical fiber 31, 32, 33, 3, respectively.
4 and optical fibers 36°37, 38.39.

Substrate 20. is an InP single crystal substrate (thickness: 300 μm) with crystal plane orientation (100).

Optical switch circuits such as optical circuit 21 are used in optical switchboards of optical subscriber networks.

Optical waveguides 22, 23, 24, 25, 26, 27°28.
No. 29 was created as follows. First, an InGaAsP optical waveguide layer (bandgap long wavelength 1.
15 pm, thickness 1.0 pm), InP cladding layer (thickness 0.5 pm), InGaAsP cap layer (thickness 0.5 pm).
μm) was grown as a multilayer crystal.

Next, a width of 5 mm was processed using a reactive ion beam etching jig.
μm, height 1.5 μm ridge type single mode optical waveguide (
A propagation wavelength of 1.3 μm) was formed.

Optical waveguides 22, 23, 24, 25 and optical waveguides 26° 27
．． At the 16 intersections of 28 and 29, carrier injection regions were formed by Zn diffusion. When a current is passed through the intersection, the refractive index of the optical waveguide changes and total reflection occurs, thereby switching the path of light.

Optical fiber 31, 32, 33, 34, 36°37.38
, 39 are silica-based single mode optical fibers. Each has an outer diameter of 125 μm and a core diameter of 9 μm.

The spot size is 5 μm. Optical fiber 31°32.
The optical fibers 33, 34 and the optical fibers 36, 37, 38, and 39 are respectively exposed by peeling off the resin coating of the tape-type four-core optical fiber core wires 30, 35.

Optical fiber 31, 32, 33, 34, 36°37.38
, 39 and optical waveguides 22, 23, 24° 25. 26, 27
, 28, 29.

Each has a similar structure. As this representative.

An optical coupling portion between the optical fiber 39 and the optical waveguide 29 is shown in FIG.

In FIG. 4, an optical waveguide 29 and a groove 42 are provided on the substrate 20.
is formed. The optical fiber 39 is installed in the V-groove 42 and is optically coupled to the optical waveguide 29. ■ Groove 42 is composed of crystal plane orientation (111) B plane, and the groove direction is <110>. ■ The abutting surface 43 of groove 42 has crystal plane orientation (
211) Consists of surfaces. (2) The groove 42 was formed as follows.

First, a glass film is formed on the surface of the substrate 20 by vapor phase chemical deposition. This glass film was patterned by photolithography, and using this as an etching mask, InP was etched in an HCQ-HaPO4 solution. As a result, crystal anisotropic etching is performed,
(111) The V-groove 42 consisting of the B surface was machined with high precision (processing accuracy ±0.2 μm).
The V-grooves in which the 32, 33, 34, 36, and 37.38 grooves were installed were also machined all at once using the same method as above.

A tip spherical lens 40 is formed at the tip of the optical fiber 39 in order to reduce optical coupling loss.

The front lens 40 connects the optical fiber 39 to HF-NH4F
Processed by etching in solution.

Ge0z contained in 5ins of the material of the optical fiber 39
Since the etching rate differs depending on the dopant such as BzOa (for the core) and BzOa (for the cladding), the core portion protrudes spherically to form the tip spherical lens 40. The lens was processed to have a radius of 13 μm.

A part of the end face of the optical fiber 39 is processed obliquely on one side 41 . The processing was carried out by grinding in the same manner as in the first example. First, tape type 4-core optical fiber 30.3
After removing the coating No. 5, the tips of the four optical fibers are cut to the same length, and the four optical fibers are lined up and ground simultaneously using a jig. Incidentally, the diagonal processing can also be performed by etching the SiOx material of the optical fiber with a hydrofluoric acid solution. In this case, the tips of four optical fibers were aligned and immersed in the etching solution.

By processing the first side 41 diagonally in this way,
The end face of the optical fiber 39 does not collide with the surface 43.
Therefore, it has become possible to bring the distance between the tip spherical lens 40 and the end face of the optical waveguide 29 close to the position of 20 μm where the optical coupling loss is lowest.

In addition, the optical fibers 31, 32, 33, 34 and the optical fiber 3
The tip spherical lens processing and diagonal processing for 6, 37, 38, and 39 were performed at once for each 30.35 tape-type four-core optical fiber.

The optical fiber 39 processed as described above is vi? 142
If the front lens 40 and the end face of the optical waveguide 29 are placed in close contact with each other, the distance between the tip lens 40 and the end face of the optical waveguide 29 is set at a predetermined position.

Low-loss optical coupling (coupling loss 1
．． 1dB) was achieved. As shown by the dashed line in FIG. 4, the optical axes of the leading waveguide 29 and the optical fiber 39 are aligned (optical axis alignment accuracy: ±0.5 μm).

Of course, other optical fibers 31, 32, 33, 34°36.
The optical coupling of 37 and 38 is similarly performed at once. That is, according to the second embodiment, there is an effect that low-loss optical coupling between the optical circuit 20 and the tape-type four-core optical fiber 30, 35 can be easily performed. The processing of the V-groove of the substrate, the tip lens of the optical fiber end face, and the sloped surface can all be done in one batch.
It has the effect of improving productivity.

Although the present invention has been described above using the first and second embodiments, the present invention can also be implemented with the following configuration.

FIG. 5 is a diagram showing a third embodiment of the present invention.

An optical waveguide 51 and a V-groove 53 are formed on the substrate 50 . A lens 52 is formed on the end face of the optical waveguide 51 by melting the surface by local heating such as laser irradiation or infrared heating. ■In the groove 53, there is an optical fiber 55.
are placed closely together. The end face of the optical fiber 55 is V
5 on one side so as not to hit the groove 54 at the end of the groove 53.
7 is processed diagonally. A spherical lens 56 is formed at the tip of the optical fiber 55 in order to reduce optical coupling damage. According to the third embodiment, the lens 52 and the spherical lens 56 form a confocal optical system. Therefore, optical coupling can be performed with extremely low loss.

FIG. 6 is a diagram showing a fourth embodiment of the present invention.
0, an optical waveguide 61 and a V-groove 62 are formed. ■
An optical fiber 64 is installed closely in the groove 62 . The end surface of the optical fiber 64 is the abutment surface 6 of the V-groove 62
The surface 66 is processed diagonally so as not to collide with the surface 3. Moreover, since the surface 65 is also processed diagonally, the tip of the optical fiber 64 is a model. According to the fourth embodiment, the optical fiber 64 and the optical waveguide 61 are directly optically coupled at the end face.
7) is also processed diagonally, which has the effect of making it easier to observe the optical coupling portion when the end faces of the optical fiber 64 and the optical waveguide 61 are butted together.

FIG. 7 is a diagram showing a fifth embodiment of the present invention.

An optical waveguide 71 and a V-groove 72 are formed on the substrate 70 . (2) An optical fiber 74 is installed closely in the groove 72. Make sure that the end surface of the optical fiber 74 does not collide with the abutment surface 73 of the V-groove 72.

The entire end face of the optical fiber 74 is processed diagonally (
surface 75) and the end surface of the optical waveguide 71 are also obliquely processed at a similar angle. The optical fiber 74 and the optical waveguide 71 are directly optically coupled at the end face.

According to the fifth embodiment, compared to processing only a portion of the end face of the optical fiber as in the previous embodiment, diagonal processing is easier to perform and workability is improved.

FIG. 8 is a diagram showing a sixth embodiment of the present invention.

An optical waveguide 81 and a V-groove 82 are formed in the substrate 80 . (2) An optical fiber 84 is left in close contact with the groove 82. In order to prevent the end face of the optical fiber 84 from colliding with the end surface 83 of the V-groove 82, the entire end face of the optical fiber 84 is processed obliquely (surface 86). In order to reduce coupling loss,
A tip spherical lens 85 is formed by etching after diagonal processing. This spherical tip lens 85 has different lens radii in the vertical and horizontal directions (x and y axis directions in the drawing). According to the sixth embodiment, even if the spot size of the optical waveguide 81 differs in the X+Y axis directions, low-loss optical coupling can be performed by adjusting the lens radius of the spherical tip lens 85.

By the way, the present invention can be applied not only to optical circuits but also to electronic integrated circuits. One example of its application is shown in the seventh embodiment shown in FIG.

FIG. 9 is a perspective view of interconnection (signal connection) of an electronic integrated circuit using optical wiring.

In FIG. 9, an electronic integrated circuit 101, leading waveguides (102, 103, etc.) and optical elements (105, 10, etc.) are disposed on a substrate 100.
6, 107, 108, etc.) are formed. Further, on the substrate 100, optical fibers 113, 114, 115, 1
V grooves (109, 110, 111°, 112, etc.) for installing 16 are machined.

The substrate 100 is a Si single crystal substrate (crystal plane orientation (100
), thickness 300um). However, electronic integrated circuit 1
In order to improve the device characteristics of 01, the plane orientation is actually slightly tilted (~4'') from the (100) axis.

The optical waveguides (102, 103, etc.) are composed of nine quartz-based three-dimensional optical waveguides. depositing a quartz glass film on the substrate 100;
This was created by patterning it by dry etching. The wavelength of the guided light is 0.8 μm. At the bent portions (104, etc.) of the optical waveguide, the guided light is totally reflected and the traveling direction of the light changes.

Among the optical elements (105, 106, 107, 108, etc.),
The optical elements (105, 107, etc.) are AQGaAs semiconductor lasers (oscillation wavelength 0.8 μm).These are made by first growing a GaAs layer by heteroepitaxial crystal growth on a Zoo (Si) substrate, and then growing an AQGaAs laser active layer v.
After sequentially growing a GaAs cap layer, the laser end face was processed by dry etching.

Among the optical elements (105, 106, 107, 108, etc.),
The optical elements (106, 108, etc.) are PIN type Si photodiodes. It was created by diffusing impurities into a substrate 100 (Si) to form a pn junction.

Note that the optical elements (105, 106, 107, 108, etc.) and the electronic integrated circuit 101 are electrically connected and can exchange signals.

Optical fiber (113, 114, 115, 116° 117
．． 118, 119, 120) are silica-based optical fibers (for wavelength 0.8 μm).

■ Grooves (109, 110, 111, 112, etc.) are the first
Processing was performed by a method similar to that described in the Examples. ■
Optical fibers (113, 114, etc.) in which the planes forming the grooves (109, 110, 111, 112, etc.) have a plane orientation of (111).
, 115, 116) are installed closely together, optical waveguides (102, 103, etc.) and optical elements (105, 106, 1
07, 108, etc.) so that the optical axis is aligned with the ■ groove (109,
110°, 111, 112, etc.) are adjusted and machined with high precision.

The electronic integrated circuit 101 includes an optical element (105, 106°10
7, 108, etc.), optical waveguides (102, 103, etc.), and optical fibers 113, 114, 115, 116, and are connected to the outside by optical wiring. In electrical wiring, signal delay due to capacitive loads is a problem, but in optical wiring,
Since there is no optical signal guidance and the signal propagation speed is very high, the optical coupling device of the present invention, which can perform high-speed signal connections, is used at such signal connection points (optical coupling points) of optical wiring.

Typical optical coupling locations in the seventh embodiment shown in FIG. 9 will be explained using FIGS. 10.11 and 12.13.

In FIG. 10, an electronic integrated circuit 10 is mounted on a substrate 100.
1. Optical waveguide 102. Optical element 105. A V-groove 109 is formed. Since the end face 121 of the optical fiber 117 is processed obliquely, the end face can be directly coupled to the leading waveguide 102 .

If the optical fiber 117 is installed closely in the groove 109,
Optical coupling with low loss is realized. The calculation processing results of the electronic integrated circuit 101 are calculated by the optical elements 1o5. Optical waveguide 102. The signal is transmitted to the outside via an optical fiber 117.

In FIG. 11, an electronic integrated circuit 10 is mounted on a substrate 100.
1. Optical waveguide 103. Optical element 106. A V groove 111 is formed. Since the end surface 122 of the optical fiber 119 is processed obliquely, the end surface can be directly coupled to the optical waveguide 103.

If the optical fiber 119 is installed closely in the V-groove 111,
Optical coupling with low loss is realized. Optical signals from the outside are transmitted through optical fiber 119. After propagating through the optical waveguide 103, the surface 123
It is reflected by the optical element 106 and enters the electronic integrated circuit 101.
can be conveyed to.

In FIG. 12, an electronic integrated circuit 10 is mounted on a substrate 100.
1. Optical element 107. A V-groove 110 is formed. A tip spherical lens 125 is formed at the tip of the optical fiber 118 . This is because the end surface 124 of the optical fiber 118 is processed obliquely.

The distance between the optical element 107 and the front lens 125 can be set to an optimal distance. Optical fiber 118 into V groove 110
Low-loss optical coupling can be achieved by placing them close to each other6.
The calculation processing results of the electronic integrated circuit 101 are calculated by the optical elements 1o7.
The signal is transmitted to the outside via an optical fiber 118.

In FIG. 13, an electronic integrated circuit 10 is mounted on a substrate 100.
1. Optical element 108. A V groove 112 is formed. Since the end surface 126 of the optical fiber 120 is processed obliquely, the end surface can be directly coupled to the optical element 108.

If the optical fiber 120 is installed closely in the V-groove 112,
Optical coupling with low loss is realized. An optical signal from the outside is transmitted through the optical fiber 120 and directly enters the optical element 108,
The information is transmitted to the electronic integrated circuit 101.

According to the optical interconnection of the seventh embodiment, high-speed, large-capacity signal connection between the electronic integrated circuit and the outside is possible, so that the calculation processing capacity of the electronic integrated circuit can be greatly improved.

As described above, a requirement of the present invention is that at least a part of the end face of the optical fiber is processed obliquely. This makes it possible to bring the end faces of the optical waveguide and the optical fiber closer to each other to a predetermined distance, thereby achieving low-loss optical coupling. Conventional optical coupling devices have the disadvantage that this interval cannot be brought close to a predetermined distance, resulting in large optical coupling loss. Note that the present invention is not limited by the configuration of the optical circuit, the material of the optical fiber, the number of cores, etc. described in the embodiments, but is applicable to an optical coupling device between an optical waveguide formed on a crystal substrate and a fiber. Take full advantage of its effects.

〔Effect of the invention〕

According to the optical coupling device of the present invention, there is an effect that low-loss optical coupling between an optical waveguide and an optical fiber can be easily realized. Therefore, the optical coupling device can be efficiently produced, which has the effect of improving economic efficiency.

Since optical coupling devices are used in various fields such as optical communication, optical information processing, optical application equipment, and optical wiring for computers, the present invention has a very large ripple effect on optical technology as a whole.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an optical coupling device according to a first embodiment of the present invention, and FIG. 2 is a partially enlarged view of the first embodiment. FIG. 3 is a perspective view of the optical coupling device of the second embodiment, and FIGS. 4, 5, 6, 7, 8, and 10. FIGS. 11, 12, and 13 are cross-sectional views showing optical coupling portions of other embodiments. FIG. 9 is a perspective view of still another embodiment as an application example of the optical coupling device of the present invention. FIG. 14 is a sectional view of a conventional optical coupling device. 1.20, 50, 60, 70, 80, 100...Substrate, 3, 4, 5, 22, 23, 24, 25, 26° 27.
28, 29, 51, 61, 71, 81゜102.103
...Optical waveguide, 6,7,8,42゜53.62,72
,82. 109, 110, 111° 112...V groove, 9, 11, 13, 31, 32° 33, 34, 36.
37, 38, 39, 55°64.74, 84. 11
3. 114. 115°116...Optical fiber, 1
0,12,14,41゜57.66.75,86. 1
21, 122, 124° 126... face, 101...
Electronic integrated circuit, 1o5゜￥, 2nd 4th concave 8th color 5J10 1wa) 11th Fig. 117, llq u1-near rl, ノ (early) 2 mouth/DO 13th ward 118, +20 7T on la Ino\”124, 1
24th side 14 tZl

Claims (1)

[Scope of Claims] 1. A crystal substrate on which an optical circuit including an optical waveguide is formed, a groove processed in the crystal substrate by crystal anisotropic etching, and a groove for optically coupling to the optical waveguide. 1. An optical coupling device comprising an optical fiber set in a groove, characterized in that at least a portion of an end surface of the optical fiber on the optical waveguide side is processed obliquely. 2. Claim 1, wherein the crystal substrate is a (100) crystal plane orientation substrate made of Si, CaAs, or InP, and the groove is a V-groove consisting of a (111) crystal plane orientation. Optical coupling device as described in . 3. The crystal substrate is made of Si and has a (100) crystal plane, and the groove has a (111) crystal plane.
2. The optical coupling device according to claim 1, wherein the optical coupling device is a groove, and the optical waveguide is made of a silica-based optical waveguide. 4. An electronic integrated circuit and an optical element are formed on the crystal substrate, and an optical fiber installed in the same V-groove as above is optically connected to the optical element. The optical coupling device according to item 1. 5. The optical coupling according to any one of claims 1, 2, 3, and 4, wherein heteroepitaxial crystal growth is performed on the crystal substrate. Device. 6. The optical coupling device according to claim 1, wherein the end face of the optical fiber is obliquely processed by grinding or etching. 7. The optical coupling device according to claim 1, wherein a spherical tip lens is formed on the end face of the optical waveguide and the optical fiber. 8. Claim 1, characterized in that the end faces of the optical waveguide and the optical fiber are fused or bonded to each other.
Optical coupling device as described in . 9. The optical coupling device according to claim 1, wherein the end face of the optical waveguide is vertically processed by etching. 10. The optical coupling device according to claim 1, wherein an anti-reflection coating is applied to at least one end face of the optical waveguide and the optical fiber. 11. Claim 1, wherein the optical fiber is fixed to the groove with solder or adhesive.
Optical coupling device as described in . 12. The method according to claim 1, wherein there is a plurality of optical fibers, and the plurality of optical fibers are tape-type multi-core optical fibers in which a plurality of coated optical fibers are collectively coated. Optical coupling device.