JP2001188146A - Optical coupling method and optical circuit - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To improve the reliability of optical coupling by physically directly bonding a flexible optical waveguide and an optical component such as a planar optical device, and to improve the reliability of the optical waveguide and the planar optical device. An optical coupling method or device that can be used in an array to easily establish large-capacity information transmission. In an optical circuit in which a planar optical element is mounted directly on a first substrate or via a second substrate on which the planar optical element is mounted, a planar optical element and a core are provided. The surface optical element 109 and the flexible optical waveguide 202 are optically coupled by physically directly bonding the end of the processed flexible optical waveguide 202 to the end.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coupling method and an optical coupling device for easily and efficiently connecting optical components such as a light emitting element, a light receiving element, and an optical waveguide with a flexible optical waveguide.

[0002]

2. Description of the Related Art With the recent improvement in circuit processing speed, signal delay and waveform distortion have occurred in electrical wiring, and accurate signal transmission has become impossible. In order to solve such a problem, attention has been paid to a conventional optical interconnection for transmitting a signal by replacing an electric signal with light. By replacing the electric signal with the optical signal, it is possible to solve the electromagnetic interference which has recently become a problem.

[0003] In the future, electric wiring composed of metal used in current electric circuit boards will be replaced by optical waveguides formed on the board, and an optical circuit for transmitting and receiving signals by light will be realized. An important issue is optical connection between an optical waveguide provided on a substrate and an optical device such as a laser diode or a photodiode, and optical connection between optical devices.

Conventionally, Japanese Patent Application Laid-Open No. 05-88028 discloses a method for connecting an optical waveguide provided on a substrate to an optical device such as a laser or a photodetector for receiving and emitting light, or for connecting optical devices. As in the optical integrated circuit described above, a method has been proposed in which optical fibers are bonded one by one. In addition, as a method of coupling a surface-type optical element that receives and emits light perpendicular to the substrate and an optical waveguide, a 45-degree mirror is provided on the end surface of the optical waveguide and the optical waveguide end surface is disposed on the surface-type optical element. Japanese Patent Application Laid-Open No. 11-38270 proposes a method for optically coupling the optical waveguide units, such as an optical waveguide unit.

[0005]

However, in the first conventional example, since one optical fiber is joined to one optical element or optical waveguide, a large number of optical elements are mounted. In an optical circuit, the manufacturing process takes a long time, and as a result, the manufacturing cost also increases.

In the second conventional example, since the optical waveguide and the surface-type optical element are not physically bonded, the coupling efficiency changes in an environment where there is shock or vibration, and the reliability of the optical coupling is changed. There was also a problem that can not be maintained.

Accordingly, an object of the present invention is to improve the reliability of optical coupling by physically directly bonding an optical component such as a planar optical device to a flexible optical waveguide, and to improve the reliability of the optical waveguide and the planar optical device. It is an object of the present invention to provide an optical coupling method and an optical circuit or an optical coupling device which can be used in an array and can easily establish an optical coupling corresponding to transmitting a large amount of information at a time.

[0008]

According to the present invention, there is provided an optical coupling method or an optical circuit for achieving the above object, wherein a planar optical element is directly or directly mounted on a first substrate. In an optical circuit mounted via a substrate (in the embodiment described later, the surface-type optical element is mounted on the second substrate and mounted on the first substrate, but the surface-type optical element is mounted on the first substrate). The planar optical element can be directly provided on the first substrate by, for example, manufacturing a monolithic substrate, or removing the growth substrate after transferring the planar optical element to the first substrate. The surface optical element and the flexible optical waveguide are optically coupled by physically directly bonding the type optical element and the end of the flexible optical waveguide in which the core is terminated and processed. I do. Thereby, the optical coupling between the flexible optical waveguide and the planar optical element can be obtained by a simple process. The bonding method includes fusion performed by melting an end of a flexible optical waveguide having a melting point of 100 ° C. or less, or UV (ultraviolet).
Adhesion that cures by irradiating UV light after aligning the end of the flexible optical waveguide with the planar optical element using a cured resin, or adhesion using an epoxy-based adhesive or the like can be used. it can. In addition, by processing the end surface at which the core of the flexible optical waveguide terminates to have a desired angle, the end of the flexible optical waveguide and the surface-type optical element or the optical waveguide can be easily formed without passing through a lens or the like. Can be optically coupled.

The following forms are possible based on the above basic configuration. The end surface where the core of the flexible optical waveguide is terminated is processed perpendicularly to the waveguide direction (optical axis) near the end, and the vertical processed surface is abutted against the surface-type optical element, and physically. It can be directly bonded (for example, see FIG. 1). Alternatively, the end surface of the flexible optical waveguide where the core is terminated is processed so as to have an angle of 45 degrees with respect to the waveguide direction (optical axis) near the end portion, and the flexible optical waveguide has a 45 ° angle.
The side surface opposite to the 45 ° processed surface may be brought into direct contact with the surface type optical element so as to physically directly adhere to the surface type optical element so that the processed surface comes to a position substantially facing the surface type optical element (for example, FIG.
reference). The 45 degree processing surface of this flexible optical waveguide
In order to enhance the optical coupling efficiency, the surface is processed into a surface which is sufficiently smooth to totally reflect light, or a metal film is formed thereon.

[0010] The first substrate includes an optical waveguide,
In the flexible optical waveguide, a mode in which the optical waveguide is optically connected to the surface-type optical element is also possible. For this reason, for example, when mounting the substrate on which the surface-type optical element is mounted on the substrate having the optical waveguide, the flexible optical waveguide can bend flexibly and absorb the deviation later without performing accurate alignment. . In the optical coupling between the optical waveguide and the flexible optical waveguide, high optical coupling efficiency can be obtained by designing the core diameters of the optical waveguide and the flexible optical waveguide to be substantially the same.

An optical connection groove is provided on the first substrate near an end face of the optical waveguide, and an end of the flexible optical waveguide where the core is terminated is inserted into the groove.
The optical waveguide and the flexible optical waveguide may be optically connected. This makes it possible to easily and optically connect the optical waveguide and the flexible optical waveguide in a self-aligned manner. If the shape of the groove and the end of the flexible optical waveguide correspond to each other (for example, see FIG. 1), self-alignment can be performed more reliably and stably. The grooves can be formed by a method such as dry etching using a reactive gas, wet etching, physical cutting, and polishing.

An optical coupling groove is provided on the first substrate near the end face of the optical waveguide, and the end of the flexible optical waveguide where the core is terminated is disposed on the groove, so that the optical waveguide and the flexible waveguide are disposed. A form in which the flexible optical waveguide and the flexible optical waveguide are optically coupled may be employed. In this case, the end face of the flexible optical waveguide can be processed so as to have an angle suitable for optically coupling the optical waveguide and the flexible optical waveguide, and the flexible optical waveguide is arranged on the light extraction or reception groove. With only this, the flexible optical waveguide and the optical waveguide can be optically coupled by a simple process. The groove can be formed by a method such as wet etching, physical cutting, and polishing.

The groove is formed substantially at the end face of the optical waveguide in the groove regardless of whether the end of the flexible optical waveguide is inserted into the groove (for example, see FIG. 1) or the groove is disposed on the groove (see FIG. 6). A mode in which the facing surface is processed so as to have an angle of 45 degrees with respect to the waveguide direction (optical axis) near the end of the optical waveguide may be adopted. Thereby, efficient optical coupling can be realized.

The surface of the groove facing the end surface of the optical waveguide may be processed into a surface that is sufficiently smooth to totally reflect light,
Here, a metal film can be formed. In the former case, polishing,
A mirror surface treatment may be performed by wet etching or the like. Thereby, the optical path conversion can be performed with further low optical loss.

The end surface of the flexible optical waveguide at which the core is terminated has a width of 4 with respect to the waveguide direction (optical axis) near the end.
The form which processes so that it may have an angle of 5 degrees can be taken. This embodiment can be adopted both when the end of the flexible optical waveguide is inserted into the groove (for example, see FIG. 1) and when it is arranged on the groove (see FIG. 6). Thereby, efficient optical coupling can be realized.

The end surface where the core of the flexible optical waveguide is terminated can be processed into a surface which is sufficiently smooth to totally reflect light, or a metal film can be formed thereon. In the former case, the end surface of the flexible optical waveguide where the core is terminated is subjected to mirror finishing by polishing, wet etching or the like. In the latter case, metals such as Ag, Au, Pt, Cr,
A material having a high reflectance, such as Al, is used, and a metal film forming method may be an electrolytic plating method, an electroless plating method, a vacuum deposition method, or the like. Thereby, the optical path conversion can be performed with further low optical loss.

In order to align the end surface of the flexible optical waveguide at which the core terminates with the surface of the groove substantially facing the end surface of the optical waveguide, the first end of the flexible optical waveguide is abutted against the first end. The substrate or the step provided on the optical waveguide may be used. The flexible optical waveguide and the optical waveguide are optically coupled in a self-aligned manner by using the step provided on the substrate having the optical waveguide to align the groove for taking out or receiving the light with the flexible optical waveguide. it can. This step can be formed by a method such as wet etching, physical cutting, or polishing.

The optical coupling between the flexible optical waveguide and the optical waveguide may be performed through a 45-degree processed surface of the flexible optical waveguide or a 45-degree processed surface of the groove (for example, see FIG. 1). Flexible optical waveguide 4
This may be performed through a 5-degree machining surface, a space in the groove, and a 45-degree machining surface of the groove (see FIG. 6).

The surface type optical element is one of a surface type light emitting element and a surface type light receiving element. Since the surface optical device is a surface light emitting device or a surface light receiving device, a structure suitable for directly bonding the end surface of the flexible optical waveguide can be obtained.

The surface emitting device may be a surface emitting semiconductor laser. Since the surface-type optical element is a surface-emitting semiconductor laser, a structure suitable for directly bonding the end face of the flexible optical waveguide can be obtained, and optical information communication and the like can be performed with low power consumption. The surface emitting semiconductor laser includes an active layer, a semiconductor multilayer mirror, a dielectric multilayer mirror, and the like, and can achieve low current driving and low power consumption. Further, when the surface-type optical element is a surface-emitting semiconductor laser, the light-emitting area is one.
On the other hand, the core of the flexible optical waveguide has a size of about 40 to 50 μm, so that high-precision alignment is not required. However, the size of the core of the flexible optical waveguide and the size of the light emitting region of the surface emitting semiconductor laser are not limited to these.

The surface light receiving device may be a semiconductor light receiving device. Since the surface type optical element is a semiconductor light receiving element,
The size of the light-receiving region can be optimized according to the balance between the size of the core of the flexible optical waveguide and the alignment accuracy.

Another surface type optical device is mounted on the first substrate directly or via a third substrate on which the other surface type optical device is mounted, and the surface type optical device and the other surface type optical device are mounted on the first substrate. One is a surface light-emitting device, the other is a surface light-receiving device, and the flexible optical waveguide has its core end-terminated and processed ends respectively as the surface light-emitting device and the surface light-receiving device. It is also possible to adopt a form in which the two are optically connected by direct bonding. Since the flexible optical waveguide optically connects the surface light-emitting element and the surface light-receiving element, for example, when mounting a substrate on which a surface optical element is mounted on a substrate having an optical waveguide, accurate alignment is required. Without this, the flexible optical waveguide can be flexibly bent later to absorb the deviation. This form can of course be used in combination with the form in which the flexible optical waveguide optically connects the optical waveguide and the planar optical element.

A plurality of planar optical devices are mounted on the first substrate or the second substrate, and the flexible optical waveguides form an array, and the plurality of planar optical devices are connected to the flexible optical waveguide array. Alternatively, optical coupling may be employed. Since the flexible optical waveguides form an array, optical elements or optical waveguides can be mounted at a high density.

[0024] The planar optical elements may form an array. Since the surface type optical elements form an array, the optical elements can be mounted at a high density, and an optical coupling method or an optical circuit suitable for large-capacity signal transmission or the like can be obtained.

The surface type optical element is provided on the first substrate or the second substrate.
Can be monolithically integrated on a single substrate. Thereby, a more compact optical circuit can be realized.

[0026]

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

(First Embodiment) FIG. 1 is a sectional view of an optical coupling method or apparatus according to a first embodiment of the present invention. FIG. 2 is a perspective view thereof. 1 and 2, the structure is such that the planar optical element array 109 and the optical waveguide array 203 composed of the optical waveguide 201 are connected using the flexible optical waveguide array 202. The optical waveguide 201 includes a core 102 and clads 103 and 104, and each optical waveguide of the flexible optical waveguide array 202 has a core 105.
And claddings 106 and 107. In this embodiment, as the surface-type optical element array 109, a surface-emitting semiconductor laser whose light-emitting portion has a size of about 10 μmφ is used.
A Si substrate is used as the substrate 101 for the substrate 09 and the substrate 108 for the optical waveguide array 203.

The flexible optical waveguide array 202 and the planar optical element array 109 mounted on the substrate 108 are arranged such that the end face where the core 105 of the flexible optical waveguide array 202 is exposed is used as a light emitting portion of the planar optical element array 109. Optically coupled by directly abutting and bonding. An epoxy adhesive is used as the adhesive. An end face of the flexible optical waveguide array 202 which is coupled to the surface type optical element array 109 is mirror-finished by polishing.

The other end of the flexible optical waveguide array 202 and the inner end of the optical waveguide array 203 are connected by providing a groove 110 in the substrate 101 near the end of the array 203 and inserting the flexible optical waveguide array 202 into the groove 110. are doing. Optical waveguide array 2 of flexible optical waveguide 202
The end surface on the side optically coupled to the surface 03 is machined into a mirror surface having an angle of 45 degrees with respect to the optical axis. Correspondingly, the bottom surface of the groove 110 also corresponds to the optical waveguide 20.
It is processed so as to have an angle of 45 degrees with respect to one optical axis. In this manner, as shown in FIG. 1, the end of the 45-degree mirror surface of the flexible optical waveguide array 202 is stably fitted and fixed to the groove 110 having a triangular cross section.

The light transmitted through the flexible optical waveguide array 202 is reflected by the 45-degree mirror end face of the core 105, converts the optical path by 90 degrees, and is introduced into the array 203 through the vertical end face of the optical waveguide array 203. . Conversely, light transmitted through the optical waveguide array 203 is also reflected at the 45-degree mirror end of the core 105 of the flexible optical waveguide array 202 and introduced into the flexible optical waveguide array 202.

The groove 110 is formed by dry etching using a reactive gas. The bottom surface (the 45-degree mirror surface) and the side surface (the vertical end surface of the optical waveguide array 203) of the groove 110 are mirror-finished by polishing to reduce light coupling loss. An epoxy adhesive is used to couple the flexible optical waveguide array 202 and the groove 110.

The flexible optical waveguide array 202
As described above, the end face of the side to be inserted into the groove 110 is processed into a shape matching the groove 110 by cutting, and is mirror-finished by polishing. Further, a metal having a high reflectance, such as Al, Au, Ag, Pt, or Cr, is deposited on the end face by a vacuum deposition method.

Optical waveguide array 2 fabricated on substrate 101
The optical waveguide 201 constituting the core 1 is the core 1 as described above.
02 and claddings 103 and 104,
This is made as follows. That is, the optical waveguide 201
Consists of a patterning step by photolithography on the substrate 101, a step of forming a groove for forming an optical waveguide in the substrate 101 by reactive ion etching using CF ₄ or Cl ₂ , and a step of forming SiO ₂ by CVD, sputter deposition, or the like. It is manufactured through a film forming step of forming the core 102 and the claddings 103 and 104 made of SiO ₂ . The refractive index of SiO ₂ of the core 102 and the claddings 103 and 104 (increase the refractive index of the core 102) is adjusted by implanting impurities.

Next, a method of forming the groove 110 for inserting the flexible optical waveguide array 202 in the substrate 101 of FIG. 1 will be described in detail with reference to FIGS. 3 (a), 3 (b) and 3 (c). First, a photoresist 301 is applied to the substrate 101 on which the optical waveguide 201 is formed as shown in FIG. Next, the photoresist 301 is exposed to UV light using a photomask 302 having a gray scale 302a. Grayscale 302a photomask 3
02, the substrate 101 as shown in FIG.
It is possible to form a pattern of the photoresist 301 having an inclination with respect to. By applying dry etching or ion sputtering using a reactive gas to the resist pattern, a desired angle of a shape suitable for inserting the end of the flexible optical waveguide array 202 as shown in FIG. Can be formed.

Next, the flexible optical waveguide array 202
4 (a), (b), (c),
This will be described in detail with reference to FIG. As the material of the core and the clad of the flexible optical waveguide array 202, polyimide having flexibility is used. As shown in FIG. 4A, a core 10 is placed on a clad 106 made of a polyimide film.
After applying the polyimide 402 to be 5 on the entire surface, a photoresist 403 is applied. As a material of the polyimide 402 to be the core 105, a material having a higher refractive index than the polyimide film to be the clad 106 is used. Thereafter, desired patterning is performed on the photoresist 403 by photolithography with UV light using a photomask 404 provided with a desired pattern (light-transmitting portions and light-shielding portions are arranged in stripes). .

Next, as shown in FIG. 4B, a pattern serving as a core of the flexible optical waveguide is formed on the polyimide 402 by a reactive ion etching method using a reactive gas. Next, by removing the remaining photoresist 403 with a remover, as shown in FIG.
The core 105 composed of the polyimide 402 remains on the upper surface. Further, as shown in FIG.
The flexible optical waveguide can be formed by covering 5 with polyimide serving as the cladding 107.

The polyimide used as the clad 107 has a smaller refractive index than the polyimide 402 used as the core. Further, it is also possible to use an air clad layer without using the polyimide to be the clad 107.

As described above, in the present embodiment, the flexible optical waveguide array 202 is used for optical coupling between the planar optical element array 109 and the optical waveguide array 203. Accordingly, when the substrate (108 in FIG. 1) on which the surface-type optical element (109 in FIG. 1) is mounted is mounted on the substrate (101 in FIG. 1) including the optical waveguide (201 in FIG. 1), accurate alignment is performed. Even if this is not done, the flexible optical waveguide (202 in FIG. 1) can be curved later to absorb this shift. Further, in the future, an optical MCM (Multiple Chip M) will be formed on a substrate on which an optical waveguide is manufactured.
The optical coupling method and apparatus according to the present embodiment are practical when a plurality of substrates are mounted and an optical waveguide of the substrate is coupled to a planar optical element on the optical MCM.

In this embodiment, the surface type optical element array 10
9. Application is also possible when the flexible optical waveguide array 202 and the optical waveguide array 203 are not an array but a single unit. The substrate 108 and the planar optical element array 109 may be monolithically integrated. In addition, since the end face of the flexible optical waveguide 202 and the planar optical element array 109 are directly bonded and coupled, optical coupling between the flexible optical waveguide 202 and the planar optical element array 109 can be obtained in a simple process. Furthermore, the direct bonding makes the optical coupling method or apparatus less likely to change the optical coupling efficiency due to vibration and impact. The surface emitting semiconductor laser has a light emitting region of about 10 μm, whereas the core 105 of the flexible optical waveguide array 202 has a thickness of 40 to 50 μm.
Since it has a size of about μm, there is no need for highly accurate alignment between the two. Therefore, when the surface-type optical element array 109 is a surface-emitting semiconductor laser, a structure suitable for directly bonding the end surface of the flexible optical waveguide array 202 can be obtained. However, the size of the core 105 and the size of the surface emitting semiconductor laser are not limited thereto.

When the planar optical element 107 is a semiconductor light receiving element, the size of the light receiving region can be designed optimally in consideration of the size of the core 105 of the flexible optical waveguide array 202 and the alignment accuracy. become. The flexible optical waveguide 202 and the optical waveguide array 203 are provided with the groove 110 in the substrate 101,
Since the flexible optical waveguide 202 is connected by inserting the flexible optical waveguide 202 into the groove 110, it is possible to manufacture an optical transmission line that transmits a large amount of information at a time in a self-aligned manner.

The substrates 101 and 1 described in the above embodiment are used.
08 can be a semiconductor substrate, a glass substrate, an electric wiring substrate, or the like, but is not limited thereto. Optical waveguide 20
1 can be manufactured by the above method, but the manufacturing method and the material are not limited thereto. In addition, the groove 110 provided in the substrate 101 was formed by dry etching using a reactive gas.
It can also be manufactured by a method such as physical cutting or polishing. Although the mirror surface treatment of the side and bottom surfaces of the groove 110 is performed by polishing, wet etching or the like may be used.

The flexible optical waveguide array 202
The material and the manufacturing method of the core 105 and the claddings 106 and 107 described above can use the material and the manufacturing method, but are not limited thereto. In order to process the end face of the flexible optical waveguide array 202 where the core 105 is terminated to have a desired angle, dry etching using a reactive gas, polishing, physical cutting, or the like can be performed. Not exclusively. In addition, as a method of forming a metal film on the end face, an electroplating method, an electroless plating method, or the like can be used, but the method is not limited thereto. Further, an epoxy-based adhesive was used for bonding the flexible optical waveguide array 202 to the surface type optical element array 109 or the optical waveguide array 203, but the bonding method was to perform fusion by melting the flexible optical waveguide, or to perform UV bonding. After aligning the flexible optical waveguide and the planar optical element using the cured resin, U
Adhesion that cures by irradiating V light can also be used. The bonding method or the material of the adhesive is not limited to this.

In this embodiment, a surface emitting semiconductor laser and a semiconductor light receiving element are used for the surface type optical element array 109. However, an LED (Light Emitting Diode) may be used instead.
Etc. can also be used.

(Second Embodiment) FIG. 5 is a sectional view showing an optical coupling method or apparatus according to a second embodiment of the present invention. FIG.
Shows a structure in which the planar optical element array 109 and the optical waveguide array 203 composed of the optical waveguide 201 are coupled by using the flexible optical waveguide array 504.

The flexible optical waveguide array 504 includes a core 501 and clads 502 and 503.
The end face of the flexible optical waveguide array 504 on the side optically coupled to the planar optical element array 109 is processed into a mirror having an angle of 45 degrees with respect to the optical axis. This mirror is manufactured by forming a slope having an angle of 45 degrees on the end face of the flexible optical waveguide array 504 by cutting and polishing, and then forming an Al thin film on the slope by vacuum evaporation. As shown in FIG. 5, the planar optical element array 109 is bonded to the side surface of the cladding 503 of the flexible optical waveguide. An epoxy adhesive is used as the adhesive.

When the surface-type optical element array 109 is a surface-emitting semiconductor laser, the light emitted from the surface-emitting semiconductor laser is bent 90 degrees by a mirror formed on the 45-degree end face of the flexible optical waveguide array 504. The core 501 of the flexible optical waveguide array 504 efficiently.
Introduced within. When the surface-type optical element 109 is a semiconductor photodetector, the light propagating through the flexible optical waveguide array 504 has its optical path bent by 90 degrees by a mirror formed on the 45-degree end face of the flexible optical waveguide array 504, so that it is efficient. Is transmitted to the semiconductor light receiving element 109.

By directly bonding and bonding the flexible optical waveguide array 504 and the planar optical element array 109,
Optical coupling between the flexible optical waveguide array 504 and the planar optical element array 109 can be obtained by a simple process. When the surface-type optical element array 109 is a surface-emitting semiconductor laser,
A structure suitable for directly bonding the side surfaces of the cladding 503 of the flexible optical waveguide array 504 can be obtained,
Optical information communication can be performed with low power consumption. When the surface type optical element array 109 is a surface emitting semiconductor laser, the light emitting area is about 10 μm, whereas the core 501 of the flexible optical waveguide array 504 is
Since it has a size of about 0 to 50 μm, high-precision alignment is not required. Furthermore, the surface type optical element array 1
When 09 is a semiconductor light receiving element, the size of the light receiving region can be set to an optimal design by taking into account the size of the core 501 of the flexible optical waveguide array 504 and the alignment accuracy.

The method of coupling the flexible optical waveguide array 504 and the optical waveguide 201 is the same as in the first embodiment. The method of manufacturing the optical waveguide 201 provided on the substrate 101 is the same as that of the first embodiment.

(Third Embodiment) FIG. 6 is a sectional view showing an optical coupling method or apparatus according to a third embodiment of the present invention. FIG.
Shows a structure in which the planar optical element array 109 and the optical waveguide 201 are coupled using the flexible optical waveguide array 604.

The flexible optical waveguide array 604 includes a core 601 and clads 602 and 603.
Flexible optical waveguide array 604 and optical waveguide 201
Is formed by providing a groove 110 having a 45-degree mirror surface on the substrate 101 having the optical waveguide 201 and aligning the 45-degree end face of the flexible optical waveguide array 604 on the groove 110 as shown in FIG. are doing. For alignment, a step 605 (for example, provided on the substrate 101)
This is performed by abutting the tip of the 45-degree mirror end face of the flexible optical waveguide array 604 against the optical waveguide array 203). The step 605 is formed, for example, by performing a photolithography process on the substrate 101 and performing wet etching. The adhesive between the flexible optical waveguide array 604 and the substrate 101 uses an epoxy-based adhesive.

The method of forming the groove 110 is the same as the method of the first embodiment, except that the groove 110 is formed in order to further reduce optical loss.
Is mirror-finished by polishing. Thus, optical coupling between the optical waveguide 201 and the flexible optical waveguide array 604 is realized with high efficiency through the 45-degree mirror surface of the groove 110 and the 45-degree mirror end surface of the flexible optical waveguide array 604.

The optical coupling method between the planar optical element array 109 and the flexible optical waveguide array 604 is as follows.
It can be realized by the same method as the embodiment. The step 605 is
After a photolithography process, a new SiO ₂ film is formed on the optical waveguide 20.
It can also be manufactured by a method such as forming it on a substrate.

(Fourth Embodiment) FIG. 7 is a sectional view of an optical coupling method or apparatus according to a fourth embodiment of the present invention. FIG.
Surface type light emitting element array 705 and surface type light receiving element array 706
Are combined using a flexible optical waveguide array 704.

The flexible optical waveguide array 704 includes a core 701 and clads 702 and 703.
The optical coupling between the flexible optical waveguide array 704 and the planar light emitting element array 705 and the planar light receiving element array 706 is realized by the same method as in the first embodiment. By using the flexible optical waveguide array 704 for optical coupling between the planar light emitting element array 705 and the planar light receiving element array 706, the substrate 707 on which the planar light emitting element array 705 is mounted and the planar light receiving element array 706 are mounted. Even if the substrate 708 has a different thickness, the displacement can be absorbed by the flexible optical waveguide array 704.

(Fifth Embodiment) FIG. 8 is a sectional view of an optical coupling method or apparatus according to a fifth embodiment of the present invention. FIG.
Surface type light emitting element array 705 and surface type light receiving element array 706
Are combined using a flexible optical waveguide array 804.

The flexible optical waveguide array 804 includes a core 801 and clads 802 and 803.
Optical coupling between the flexible optical waveguide array 804 and the planar light emitting element array 705 and the planar light receiving element array 706 is realized by the same method as in the second embodiment. Also in this embodiment, by using the flexible optical waveguide array 804 for optical coupling between the surface light emitting element array 705 and the surface light receiving element array 706, the surface light emitting element array
705 on which substrate 05 is mounted and surface-type light receiving element array 706
Has a different thickness from the substrate 708 on which the
The shift can be absorbed by the flexible optical waveguide array 804.

[0057]

As described above, according to the optical coupling method and apparatus according to the present invention, the reliability of optical coupling is improved by physically directly bonding the flexible optical waveguide and the planar optical element. In addition, the flexible optical waveguide and the planar optical element can be used in an array, and an optical coupling that can cope with transmitting a large amount of information at a time can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an optical coupling method and an optical circuit according to a first embodiment of the present invention.

FIG. 2 is a perspective view of FIG.

FIG. 3 is a process sectional view showing an optical coupling method and a method of manufacturing an optical waveguide on a substrate used in an optical circuit according to the first embodiment of the present invention.

FIG. 4 is a process cross-sectional view showing an optical coupling method and a method of manufacturing a flexible waveguide used in an optical circuit according to the first embodiment of the present invention.

FIG. 5 is a sectional view showing an optical coupling method and an optical circuit according to a second embodiment of the present invention.

FIG. 6 is a sectional view showing an optical coupling method and an optical circuit according to a third embodiment of the present invention.

FIG. 7 is a sectional view showing an optical coupling method and an optical circuit according to a fourth embodiment of the present invention.

FIG. 8 is a sectional view showing an optical coupling method and an optical circuit according to a fifth embodiment of the present invention.

[Explanation of symbols]

101 substrate 102 core of optical waveguide 103, 104 cladding of optical waveguide 105, 501, 601, 701, 801 core of flexible optical waveguide 106, 107, 502, 503, 602, 603, 7
02, 703, 802, 803 Flexible optical waveguide cladding 108 Optical element substrate 109 Surface type optical element array 110 Groove 201 Optical waveguide 202, 504, 604, 704, 804 Flexible optical waveguide array 203 Optical waveguide array 301 Photoresist 302 Gray Photomask having scale 402 Polyimide 403 Photoresist 404 Photomask for forming flexible optical waveguide array 705 Surface light emitting element array 706 Surface light receiving element array 707 Substrate of light emitting element array 708 Substrate of light receiving element array

Claims (46)

[Claims] 1. A method for optically coupling an optical circuit in which a surface-type optical element is mounted on a first substrate directly or via a second substrate on which the surface-type optical element is mounted. An optical coupling method, wherein the planar optical element and the flexible optical waveguide are optically coupled by physically directly bonding the end of the flexible optical waveguide which is processed by terminating the surface optical element. 2. An end face at which a core of the flexible optical waveguide is terminated is processed perpendicularly to a waveguide direction (optical axis) near the end, and the vertical processed face is projected to the surface type optical element. 2. The optical coupling method according to claim 1, wherein the optical coupling is performed by direct physical contact. 3. An end face at which the core of the flexible optical waveguide terminates is positioned at 4 degrees with respect to the waveguide direction (optical axis) near the end.
The flexible optical waveguide is processed so as to have an angle of 5 degrees, and the side surface on the opposite side of the 45-degree processed surface is set to the surface-type light so that the 45-degree processed surface of the flexible optical waveguide comes to a position substantially facing the surface-type optical element. The optical coupling method according to claim 1, wherein the optical coupling is performed by physically directly bonding the element to the element. 4. The optical coupling method according to claim 3, wherein the 45-degree processing surface of the flexible optical waveguide is processed into a surface that is sufficiently smooth to totally reflect light. 5. The optical coupling method according to claim 3, wherein a metal film is formed on a 45 ° processed surface of the flexible optical waveguide. 6. The first substrate includes an optical waveguide,
2. The flexible optical waveguide according to claim 1, wherein the optical waveguide is optically connected to the planar optical element.
6. The optical coupling method according to any one of claims 1 to 5. 7. A groove for optical connection is provided near an end face of the optical waveguide on the first substrate, and an end of the flexible optical waveguide where a core is terminated is inserted into the groove.
7. The optical coupling method according to claim 6, wherein the optical waveguide is optically connected to the flexible optical waveguide. 8. The optical waveguide according to claim 1, wherein a groove for optical coupling is provided near an end face of the optical waveguide on the first substrate, and an end of the flexible optical waveguide where the core is terminated is disposed on the groove. 7. The optical coupling method according to claim 6, wherein the optical waveguide is optically coupled to the flexible optical waveguide. 9. A method in which a surface of the groove substantially facing the end face of the optical waveguide is processed so as to have an angle of 45 degrees with respect to a waveguide direction (optical axis) near an end of the optical waveguide. The optical coupling method according to claim 7 or 8, wherein: 10. The optical coupling method according to claim 9, wherein a surface of the groove facing the end face of the optical waveguide is processed into a surface that is sufficiently smooth to totally reflect light. 11. The optical coupling method according to claim 9, wherein a metal film is formed on a surface of said groove facing an end surface of said optical waveguide. 12. An end face at which a core of the flexible optical waveguide is terminated is processed so as to have an angle of 45 degrees with respect to a waveguide direction (optical axis) near the end. 12. The optical coupling method according to any one of 7 to 11. 13. The optical coupling method according to claim 12, wherein an end surface of the flexible optical waveguide at which the core is terminated is processed into a surface which is sufficiently smooth to totally reflect light. 14. The optical coupling method according to claim 12, wherein a metal film is formed on an end surface of the flexible optical waveguide where a core is terminated. 15. The flexible optical waveguide according to claim 1, wherein an end of said flexible optical waveguide is aligned with a surface of said groove which is substantially opposed to an end of said optical waveguide. 15. The optical coupling method according to claim 8, wherein a step provided on the first substrate or the optical waveguide is used. 16. An optical coupling between the flexible optical waveguide and the optical waveguide, wherein the optical coupling between the flexible optical waveguide and the flexible optical waveguide is 45 degrees.
The optical coupling method according to any one of claims 9 to 14, wherein the light coupling is performed through a 45 degree processing surface or a 45 degree processing surface of the groove. 17. An optical coupling between the flexible optical waveguide and the optical waveguide, wherein the optical coupling of the flexible optical waveguide
The optical coupling method according to any one of claims 9 to 15, wherein the optical coupling is performed through a degree processing surface, a space of the groove, and a 45 degree processing surface of the groove. 18. A surface light emitting device according to claim 1, wherein said surface light emitting device is one of a surface light emitting device and a surface light receiving device.
The optical coupling method according to any one of the above. 19. An optical coupling method according to claim 18, wherein said surface emitting device is a surface emitting semiconductor laser. 20. The optical coupling method according to claim 18, wherein said surface type light receiving element is a semiconductor light receiving element. 21. A planar optical device, wherein another planar optical element is mounted on the first substrate directly or via a third substrate on which the planar optical device is mounted. One of the elements is a surface light-emitting element, the other is a surface light-receiving element, and the flexible optical waveguides each have a core-terminated end processed with the surface light-emitting element and the surface light-receiving element. The optical coupling method according to any one of claims 1 to 5, wherein the two are optically connected by being physically directly bonded to the optical fiber. 22. A plurality of planar optical devices are mounted on the first substrate or the second substrate, and the flexible optical waveguide forms an array, and the plurality of planar optical devices are connected to the flexible optical waveguide. 22. The optical coupling method according to claim 1, wherein each of the optical couplings is optically coupled to the wave path array. 23. The optical coupling method according to claim 22, wherein said surface type optical elements form an array. 24. The optical coupling method according to claim 22, wherein said surface type optical element is monolithically integrated on said first substrate or said second substrate. 25. In an optical circuit in which a surface type optical element is mounted on a first substrate directly or via a second substrate on which the surface type optical element is mounted, the surface type optical element and a core are terminated. An optical circuit, wherein the planar optical element and the flexible optical waveguide are optically coupled by physically directly bonding the end of the processed flexible optical waveguide. 26. An end face at which the core of the flexible optical waveguide terminates is processed perpendicularly to the waveguide direction (optical axis) near the end, and the vertical processed face projects from the surface type optical element. 26. The optical circuit according to claim 25, wherein the optical circuit is physically directly adhered. 27. An end face at which a core of the flexible optical waveguide is terminated is processed so as to have an angle of 45 degrees with respect to a waveguide direction (optical axis) near the end, and the flexible optical waveguide has a 45 ° angle. The side surface opposite to the 45 ° processed surface is physically directly adhered to the surface type optical element so that the surface processed surface comes to a position substantially facing the surface type optical element. An optical circuit according to claim 25. 28. The optical circuit according to claim 27, wherein the 45-degree processed surface of the flexible optical waveguide is processed into a surface that is sufficiently smooth to totally reflect light. 29. The flexible optical waveguide according to claim 2, wherein a metal film is formed on a 45 ° processed surface.
7. The optical circuit according to 7. 30. The first substrate includes an optical waveguide, and the optical waveguide and the planar optical element are optically connected by the flexible optical waveguide. 30. The optical circuit according to any one of claims to 29. 31. A groove for optical connection is provided in the first substrate near an end face of the optical waveguide, and an end of the flexible optical waveguide where a core is terminated is inserted into the groove. 31. The optical circuit according to claim 30, wherein the optical waveguide and the flexible optical waveguide are optically connected. 32. An optical coupling groove is provided in the first substrate near an end face of the optical waveguide, and an end of the flexible optical waveguide where a core is terminated is disposed on the groove. 31. The optical circuit according to claim 30, wherein the optical waveguide and the flexible optical waveguide are optically coupled. 33. The surface of the groove substantially facing the end surface of the optical waveguide is processed so as to have an angle of 45 degrees with respect to the waveguide direction (optical axis) near the end of the optical waveguide. 33. The optical circuit according to claim 31, wherein: 34. The optical circuit according to claim 33, wherein the surface of the groove facing the end face of the optical waveguide is processed into a surface that is sufficiently smooth to totally reflect light. 35. A metal film is formed on a surface of the groove facing an end surface of the optical waveguide.
3. The optical circuit according to 3. 36. An end face where the core of the flexible optical waveguide is terminated is processed so as to have an angle of 45 degrees with respect to a waveguide direction (optical axis) near the end. The optical circuit according to any one of claims 31 to 35. 37. The optical circuit according to claim 36, wherein an end face of the flexible optical waveguide at which the core terminates is processed into a smooth surface sufficient to totally reflect light. 38. The optical circuit according to claim 36, wherein a metal film is formed on an end face of the flexible optical waveguide where the core is terminated. 39. An end face of the flexible optical waveguide is abutted to align an end face of the flexible optical waveguide where the core is terminated with a face of the groove substantially facing the end face of the optical waveguide. 39. The optical circuit according to claim 32, wherein a step is provided on the first substrate or the optical waveguide. 40. The surface type optical element is one of a surface type light emitting element and a surface type light receiving element.
10. The optical circuit according to any one of 9 above. 41. An optical circuit according to claim 40, wherein said surface light emitting device is a surface emitting semiconductor laser. 42. The optical circuit according to claim 40, wherein said surface light receiving element is a semiconductor light receiving element. 43. Another planar optical element is mounted on the first substrate directly or via a third substrate on which the planar optical element is mounted, and the planar optical element and the other planar optical element are mounted on the first substrate. One of the elements is a surface light-emitting element, the other is a surface light-receiving element, and the flexible optical waveguides each have a core-terminated end processed with the surface light-emitting element and the surface light-receiving element. The optical circuit according to any one of claims 25 to 29, wherein both are optically connected by being physically directly bonded to the optical circuit. 44. A plurality of planar optical devices are mounted on the first substrate or the second substrate, and the flexible optical waveguide forms an array, and the plurality of planar optical devices are connected to the flexible optical waveguide. The optical circuit according to any one of claims 25 to 43, wherein each of the optical circuits is optically coupled to the wave path array. 45. The optical circuit according to claim 44, wherein said surface type optical elements form an array. 46. The optical circuit according to claim 44, wherein the surface type optical element is monolithically integrated on the first substrate or the second substrate.