JP4308542B2 - Waveguide type optical coupling element, optical wiring, and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a waveguide type optical coupling element, an optical wiring, and a manufacturing method thereof.
[0002]
[Prior art]
As a method of optically coupling a light emitting side element that emits light and a light incident side element that enters light, no element for optical coupling is provided between the light emitting side element and the light incident side element. A method (generally called an end face connection or a direct connection) is known (see Patent Document 1). FIG. 17 is an invention disclosed in Patent Document 1, in which an optical element (laser diode) 103 is mounted on a sub-substrate 101 via bumps 102 and the optical element 103 is directly optically coupled to the optical fiber 104. . In the present invention, in order to eliminate the need for position control with a high-precision optical mounting machine at the time of mounting, the optical element 103 and the sub-board 101 are mounted by mounting the optical element 103 on the sub-board 101 via the bumps 102. Position control is performed. Further, the V-groove 105 formed by using the photolithography process is provided in the sub-substrate 101, and the optical fiber 104 and the optical element 103 are controlled by inserting the optical fiber 104 into the V-groove 105.
[0003]
Further, in direct coupling, there has been proposed an invention in which a liquid or an adhesive is interposed instead of air between a light emitting side element that emits light and a light incident side element that enters light (Patent Documents 2 and 3). reference). This adhesive has two functions of fixing the position and reducing the refractive index difference. In order to eliminate the presence of an air layer, the adhesive is in a liquid state at the time of dispensing. It can be changed to a high material or a highly elastic body.
[0004]
Further, an invention in which an optical coupling element is provided between a light emitting side element and a light incident side element has been proposed (see Patent Document 4). In the present invention, a light guide path filled with a flexible light transmitting member inside a tapered member is used as an optical coupling element, and the position control of the optical fiber is performed in a tapered shape.
[0005]
[Patent Document 1]
Japanese Patent No. 2616550
[Patent Document 2]
Japanese Patent Laid-Open No. 5-107425
[Patent Document 3]
Japanese Patent Laid-Open No. 7-27946
[Patent Document 4]
JP 2001-59919 A
[0006]
[Problems to be solved by the invention]
The invention disclosed in Patent Document 1 does not require a high-precision optical mounting machine at the time of mounting, but requires a sub-board 101 on which bumps 102 and V-grooves 105 are formed. It will never be cheaper.
[0007]
In the inventions disclosed in Patent Documents 2 and 3, a high-precision optical mounting machine is required for aligning the light emitting side element and the light incident side element, and the mounting cost also increases.
[0008]
In the invention disclosed in Patent Document 4, the alignment between the tapered member and the optical fiber can be performed without using an optical mounting machine, but the position of the tapered member and the light emitting side element (optical semiconductor). An optical mounting machine is required for matching, and the overall mounting cost increases.
[0009]
An object of the present invention is to eliminate the need for highly accurate alignment when optically coupling a light emitting side element and a light incident side element, and to reduce the cost when optically coupling.
[0010]
Another object of the present invention is to increase the optical coupling efficiency between the light emitting side element and the light incident side element.
[0011]
Another object of the present invention is to improve the mechanical strength and reliability of optical coupling between the light emitting side element and the light incident side element.
[0012]
Another object of the present invention is to reduce the loss in optical coupling between the light emitting side element and the light incident side.
[0013]
[Means for Solving the Problems]
The invention according to claim 1 optically couples the light emitting side element that emits light and the light incident side element that enters light.Using a core and clad waveguideIn the waveguide type optical coupling element, the waveguide type optical coupling element isElastic constant 10 ² dyn / cm ³ 10 or more ⁸ dyn / cm ³ IsIt consists of a low elastic body material, and can be self-supported in the state of a low elastic body material.
[0014]
Therefore, even when the optical axis of the light emitting side element and the optical axis of the light incident side element are deviated, the waveguide type optical coupling element is formed of a low elastic material, so that it deforms according to the deviation. Therefore, when optically coupling the light emitting side element and the light incident side element, high-accuracy alignment is unnecessary, and the cost for optical coupling is reduced. Furthermore, since the light travels in a state confined in the waveguide, the optical coupling efficiency between the light emitting side element and the light incident side element is increased.
[0015]
In the present invention, “low elasticity” is a state with respect to viscoelasticity possessed by soft and stretchable gels or rubbers or many polymer compounds, and is made of ceramics, glass or TiO 2.₂And SiO₂Such a state is different from the highly elastic state of the optical crystal. The hardness is low Vickers hardness, and the elastic constant and viscosity are small values. In addition, “low elasticity” here indicates that the waveguide type optical coupling element can be deformed while being self-supported without being destroyed by the action of a tensile force with respect to the amount of deviation of the optical axis. . More specifically, the elastic constant is 10²dyn / cm³10 or more⁸dyn / cm³It is as follows. 10²dyn / cm³Less than 10 and it is difficult to support itself.⁸dyn / cm³If the optical axis is larger, the waveguide type optical coupling element has an optical axis shift of 0.5 μm or more depending on the shape of the waveguide type optical coupling element and the characteristics and arrangement of the light receiving element and the light emitting element. It is difficult to realize sufficient optical axis deflection with respect to the waveguide. More preferably, 10³dyn / cm³10 or more⁶dyn / cm³As described below, sufficient self-supporting strength and high optical coupling efficiency due to deformation of the optical axis of the waveguide type optical coupling element corresponding to 1 μm or more can be realized. Moreover, in Vickers hardness, it is preferable that it is 5 or less.
[0016]
In addition, this departureClearlyIn this case, “self-supporting” means that it has a strength capable of maintaining its shape by supporting both ends even if it is not placed on the substrate.
[0017]
Further, in the present invention and each of the following inventions, the “waveguide” has an action of confining light in the inside thereof, unlike a simple adhesive. For this reason, the distance between the light emitting side element and the light incident side element does not need to be sufficiently small with respect to the cross-sectional area of the waveguide, and low-loss light is obtained even at a distance longer than the equivalent diameter given by the cross-sectional area. Bonding can be realized.
[0058]
The invention according to claim 2 is the waveguide type optical coupling element according to claim 1, whereinHigh elasticity relative to the low elastic materialA coating layer made of a highly elastic material is provided.
[0059]
Therefore, by providing this covering layer, the mechanical strength and reliability of the waveguide type optical coupling element are improved.
[0084]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic view showing an optical wiring having a light emitting element module 1, a light receiving element module 2, a lens 3, and a waveguide type optical coupling element 4 which are light emitting side elements. The light receiving element module 2 and the lens 3 are connected by connecting means (not shown) to form a light incident side element 14.
[0085]
The light emitting element module 1 includes a light emitting element substrate 5, a surface type light emitting element 6 mounted on the light emitting element substrate 5, a light emitting element case 7 surrounding the light emitting element 6, and an emission side surface of the light emitting element case 7. The glass window 8 is provided.
[0086]
The light receiving element module 2 is provided on a light receiving element substrate 9, a light receiving element 10 mounted on the light receiving element substrate 9, a light receiving element case 11 surrounding the light receiving element 10, and a light receiving side surface of the light receiving element case 1. And the glass window 12 formed.
[0087]
The lens 3 serves to form an image of light emitted from the light emitting element 6 on the light receiving element 10.
[0088]
The waveguide type optical coupling element 4 has a contact fixing part 4a that is closely fixed to the glass window 8 of the light emitting element module 1 at one end and a contact fixing part 4b that is closely fixed to the surface of the lens 3 at the other end. is doing. Here, the laser beam 13a emitted from the light emitting element 6 is optically coupled to the waveguide type optical coupling element 4 that is tightly fixed to the glass window 8, and propagates through the waveguide type optical coupling element 4 to be used for optical coupling. The light is condensed by the lens 3 and becomes a light-receiving light beam 13b propagating in space, which enters the light-receiving element 10 in the light-receiving element module 2 and is photoelectrically converted. At this time, information can be transmitted between the light emitting element module 1 and the light receiving element module 2 by modulating the laser beam 13a in accordance with the information.
[0089]
The waveguide type optical coupling element 4 is a self-supporting waveguide, and can be self-supported even if it is not provided on a substrate. The self-supporting waveguide here refers to a waveguide made of a waveguide material having a strength capable of maintaining the waveguide structure by supporting both ends. Therefore, the waveguide type optical coupling element 4 can be provided in the air with both ends supported by the glass window 8 and the lens 3.
[0090]
In addition, since this waveguide type optical coupling element 4 is a self-supporting waveguide as well as a waveguide, it has an action of confining light inside the adhesive, unlike an adhesive used between the waveguides. For this reason, the distance between the glass window 8 and the lens 3 need not be sufficiently small with respect to the cross-sectional area, and low-loss optical coupling can be realized even at a distance longer than the equivalent diameter given by the cross-sectional area. Can do.
[0091]
Further, the waveguide type optical coupling element 4 made of this self-supporting waveguide is made of a low elastic material. Since it is made of a low elastic material, it has shape deformability, and therefore, even when the optical axes of the light emitting element 6 and the lens 3 at both ends of the waveguide type optical coupling element 4 do not coincide with each other, the waveguide itself By deforming the shape and spontaneously deflecting the optical axis of the waveguide type optical coupling element 4 itself, high-efficiency optical coupling can be realized.
[0092]
In addition, even when the temperature changes and the position shifts due to the difference in expansion coefficient, the shape of the waveguide itself is deformable because it is made of a low elastic material. To achieve high-efficiency optical coupling.
[0093]
Low elasticity here is a state with respect to the viscoelasticity which soft and elastic gel or rubber or many high molecular compounds have, and is ceramic, glass, or TiO.₂And SiO₂Such a state is different from the highly elastic state of the optical crystal. The hardness is low Vickers hardness, and the elastic constant and viscosity are small values. The low elasticity here indicates that the waveguide type optical coupling element 4 can be deformed while being self-supported without being destroyed by the action of a tensile force with respect to the amount of deviation of the optical axis. More specifically, the elastic constant is 10²dyn / cm³10 or more⁸dyn / cm³It is as follows. 10²dyn / cm³Less than 10 is difficult to self-support.⁸dyn / cm³If it is larger, depending on the shape of the waveguide type optical coupling element 4 and the characteristics and arrangement of the light emitting element 6, the waveguide type optical coupling element 4 is not affected by the optical axis shift of 0.5 μm or more. It is difficult to realize sufficient optical axis deflection with respect to the waveguide. More preferably, 10³dyn / cm³10 or more⁶dyn / cm³As described below, sufficient self-supporting strength and high optical coupling efficiency due to deformation of the optical axis of the waveguide type optical coupling element 4 corresponding to 1 μm or more can be realized. Moreover, in Vickers hardness, it is preferable that it is 5 or less. At the same time, unlike conventional waveguide materials, it is preferable to have soft stretchability, and a material that does not break even when stretched to 120% or more is used.
[0094]
As this low elastic material, since it is also a waveguide, it is preferable that the material has a low loss, and as the gel, a material containing a solvent in which an acrylate material is polymerized or a material in which a solvent structure is polymerized, A silicone material having a siloxane bond can be used. Similarly, a normal rubber material can be used as the rubber material, and at the same time, a chicone material or the like can be used. Furthermore, as a soft polymer material, a polymer material having many amorphous portions can be used.
[0095]
The waveguide type optical coupling element 4 made of this low elastic material is self-supporting and also functions as a self-shaped waveguide. This is because, since the low elastic material has a deformability, the surface tension of the waveguide type optical coupling element 4 is smoothed by the surface tension, unlike the waveguide molded by the mold, so that the loss can be reduced. At the same time, the tension is applied to the light emitting element module 1 and the lens 3 supported at both ends, and the shape is controlled so that the distance of the optical axis is minimized. Thereby, a lower-loss waveguide can be realized. In addition to the physical property values related to the waveguide-type optical coupling element 4 such as the amount of the waveguide-type optical coupling element, the elastic constant, and the rheological characteristics, this self-molded shape is the shape of the support that supports this at both ends, Furthermore, the surface performance such as hydrophilicity and hydrophobicity can be controlled.
[0096]
Furthermore, since the waveguide type optical coupling element 4 made of the low elastic material has a tension acting on the supports at both ends thereof, the light emitting element module 1 that supports the waveguide type optical coupling element 4 at both ends or By providing mobility to at least one of the lenses 3, the position can be controlled. Thereby, highly accurate self-alignment can also be realized.
[0097]
Further, the waveguide type optical coupling element 4 made of this low elastic material can be provided with an action of assembling and installing the lens 3 itself by imparting adhesiveness. In the case of using a silicone material having a siloxane bond or the like, a good adhesive force can be obtained by performing a hydrophilic treatment in advance. By providing a precoat layer in addition to the hydrophilic treatment, good adhesive force can be obtained.
[0098]
Further, the waveguide type optical coupling element 4 may be provided alone without using the lens 3. That is, the waveguide type optical coupling element 4 may be supported at both ends by the glass window 8 of the light emitting element module 1 and the glass window 12 of the light receiving element module 2. At this time, light from the light emitting element 6 optically coupled to the waveguide type optical coupling element 4 is directly emitted from the glass window 12 of the light receiving element module 2 into the light receiving element module 2 and enters the light receiving element 10.
[0099]
The shape of the waveguide type optical coupling element 4 is not limited to the pincushion taper shape as shown in FIG. This shape is due to the shift of the optical axis between the light-emitting element module 1 and the light-receiving element module 2 in the case of self-alignment, the gap between the two spaces, the amount of material of the waveguide type optical coupling element 4, and the support at both ends. Depending on the method, etc.
[0100]
Here, as a material of the waveguide type optical coupling element 4, in addition to the materials described above, those described below can be used. For example, a material having a glass transition point of 0 degrees or less and capable of self-supporting above the glass transition point, a material composed of a thermoplastic low-elasticity material and capable of self-supporting in the state of the thermoplastic low-elasticity material, Materials that are self-supporting made of photosensitive low-elasticity material, materials that are low-elasticity material having a microphase-separated structure below the wavelength of light, materials that can be self-supporting in the state of this low-elasticity material, self-supporting Fluoro rubber, self-supporting acrylic acid or methacrylic acid copolymer.
[0101]
FIG. 2 explains the action of spontaneously deflecting the optical axis of the waveguide type optical coupling element 4 itself. FIG. 2A shows the case where the optical axes of the light emitting element module 1 and the lens 3 coincide with each other. (B) is a case where the optical axes of the light emitting element module 1 and the lens 3 do not coincide.
[0102]
2A, since the optical axes of the light emitting element module 1 and the lens 3 coincide with each other as described in FIG. 1, the taper shape of the waveguide type optical coupling element 4 and the lens curvature are expressed as follows. Highly efficient optical coupling can be realized by optimally designing in accordance with the distance between the light emitting element module 1 and the light receiving element module 2, the refractive index of the waveguide type optical coupling element 4 and the lens 3, and the like.
[0103]
On the other hand, FIG. 2B shows a case where the optical axes of the light emitting element module 1 and the lens 3 are shifted and do not coincide with each other because alignment is not performed with high accuracy. However, since the waveguide type optical coupling element 4 is made of a low elastic material, its shape is deformed corresponding to the deviation of the optical axis. At this time, the waveguide light is confined in the deformed waveguide because of the waveguide structure. Therefore, the main traveling direction (pointing vector) is deflected as the guided light in the waveguide type optical coupling element 4, so that the optical coupling to the light receiving element 10 in the light receiving element module 2 is high. Can be combined with efficiency.
[0104]
Furthermore, the waveguide type optical coupling element 4 using this low-elasticity material is not limited to the position adjustment at the time of assembly, and the positional deviation between the light emitting element module 1 and the lens 3 due to the thermal change after the assembly, Even when the light-emitting element module 1 and the lens 3 are displaced for a short time due to vibration, the shape of the waveguide-type optical coupling element 4 itself is deformed, so that a decrease in optical coupling efficiency can be reduced.
[0105]
FIG. 3 is a comparative example in which the waveguide type optical coupling element 4 is omitted from the configuration of FIG. FIG. 3A shows a state corresponding to FIG. 2A, and the optical axes of the light emitting element module 1 and the lens 3 coincide with each other. FIG. 3B is a state corresponding to FIG. 2B, and the optical axes of the light emitting element module 1 and the lens 3 are shifted and do not coincide with each other because alignment is not performed with high accuracy.
[0106]
In FIG. 3A, the laser light 13a emitted from the light emitting element 6 is favorably incident on the light receiving element 10 in the light receiving element module 2, and high optical coupling efficiency is obtained. On the other hand, in the case of 3 (b), the effective optical axis of the lens 3 is inclined, so that the light cannot be collected in the surface of the light receiving element 10 and the light coupling efficiency is low.
[0107]
A second embodiment of the present invention will be described with reference to FIG. The same parts as those described in FIGS. 1 to 3 are denoted by the same reference numerals, and description thereof is also omitted (the same applies to the following embodiments).
[0108]
In the present embodiment, a coating layer 15 made of a highly elastic material is provided around the waveguide type optical coupling element 4.
[0109]
By providing such a coating layer 15, the mechanical strength and reliability of the waveguide type optical coupling element 4 are improved.
[0110]
A third embodiment of the present invention will be described with reference to FIG. In this embodiment, the waveguide type optical coupling element 16 is not formed from a homogeneous constituent material, but is formed so as to have different refractive index distributions. In the waveguide type optical coupling element 15 of FIG. 5, the dark color portion near the optical axis has a high refractive index, and the light color portion near the interface has a low refractive index. The refractive index distribution is more preferably a distribution according to the square of the radius like a 50 um multimode fiber, but is not limited thereto. The refractive index distribution type waveguide optical coupling element 16 having a small refractive index near the interface is unlikely to cause an increase in propagation loss due to a shape change in the vicinity of the interface, so that a low loss waveguide type optical coupling element 16 is configured. Can do.
[0111]
A fourth embodiment of the present invention will be described with reference to FIG. In the optical wiring of the present embodiment, a waveguide optical wiring 17 is provided in place of the light receiving element module 2, and the light incident side element 14 is configured by the waveguide optical wiring 17 and the lens 3. The waveguide optical wiring 17 is composed of a core 17a having a large refractive index and a clad 17b having a small refractive index positioned surrounding the core 17a. A waveguide type optical coupling element 4 is provided between the light emitting element module 1 and the lens 3.
[0112]
In this optical wiring, the laser beam 13 a emitted from the light emitting element 6 is optically coupled to the waveguide type optical coupling element 4 in close contact with the glass window 8 of the light emitting element module 1, and then collected by the optical coupling lens 3. The received light beam 13b is transmitted and propagates in space, and this received light beam 13b can enter the core 17a of the waveguide optical wiring 17 and be optically coupled with high efficiency.
[0113]
In general, the optical wiring provided on the substrate shifts the optical axis between the light emitting element module 1 and the core 17a of the waveguide optical wiring 17 due to the positional deviation of the formed waveguide itself or the thermal expansion of the substrate. Easy to shift.
[0114]
However, in the present embodiment, as shown in FIG. 6, the light from the light emitting element module 1 can be optically coupled to the waveguide optical wiring 17 by the waveguide type optical coupling element 4 having a self-alignment function. A low-loss optical wiring can be realized.
[0115]
In addition, when the waveguide optical wiring 17 is a multimode waveguide, there are many modes unlike a single mode waveguide, so that mode conversion occurs on the curved surface serving as the interface of the waveguide type optical coupling element 4. Even in this case, since it is only necessary to convert to another mode, the loss is much lower than that of a single mode waveguide type optical coupling element.
[0116]
A fifth embodiment of the present invention will be described with reference to FIG. In the optical wiring of the present embodiment, a waveguide optical wiring 18 is provided instead of the light emitting element module 1 as a light emitting side element. The waveguide optical wiring 18 is composed of a core 18a having a high refractive index and a clad 18b having a low refractive index located across the core 18a. A waveguide type optical coupling element 4 is provided between the waveguide optical wiring 18 and the lens 3.
[0117]
In this optical wiring, the outgoing light beam from the waveguide optical wiring 18 is optically coupled to the waveguide type optical coupling element 4, and then condensed by the lens 3 for optical coupling to become a received light beam 13b propagating in space. This received light beam 13b can be optically coupled to the light receiving element 10 of the light receiving element module 2 with high efficiency.
[0118]
In general, the optical wiring provided on the substrate is likely to shift the optical axis or the distance between the waveguide optical wiring 18 and the lens 3 due to the positional shift of the formed waveguide itself or the thermal expansion of the substrate.
[0119]
However, in this embodiment, as shown in FIG. 7, the light from the core 18a of the waveguide optical wiring 18 can be optically coupled by the waveguide type optical coupling element 4 having a self-alignment function. It becomes possible to realize the optical wiring.
[0120]
A sixth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the waveguide optical wiring 20 that is the light emitting side element, the waveguide optical wiring 21 that is the light incident side wiring, and the waveguide optical wiring 20 and 21 are positioned between these waveguide optical wirings 20 and 21. The optical wiring 22 is disposed in the horizontal direction, and is bonded to the substrate 23 with an adhesive layer 24. These waveguide optical wirings 20, 21, and 22 are respectively composed of cores 20a, 21a, and 22a having a large refractive index and clads 20b, 21b, and 22b having a small refractive index that are positioned around the cores 20a, 21a, and 22a. It is configured.
[0121]
A waveguide type optical coupling element 4 is provided between the end face on the light emitting side of the waveguide optical wiring 20 and one end face of the waveguide optical wiring 22, and the other end face of the waveguide optical wiring 22 and the waveguide light. A waveguide type optical coupling element 4 is provided between the end face on the incident side of the wiring 21.
[0122]
Since the waveguide type optical coupling elements 4 are provided at both ends of the central waveguide optical wiring 22, the height of the optical axis of the waveguide optical wiring 22 on the substrate 23 from the substrate 23 is the other two waveguides. Even when the optical axes of the waveguide optical wirings 20 and 21 are deviated from each other, high coupling efficiency can be obtained between the waveguide optical wiring 20 and the waveguide optical wiring 21. Further, even if the optical axes of the waveguide optical wiring 20 and the waveguide optical wiring 21 are shifted from each other from the substrate 23, the production accuracy of the height of the optical axis of the waveguide optical wiring 22 from the substrate 23 is improved. The horizontal alignment accuracy of the plurality of waveguide optical wirings 20, 21, and 22 wired in the horizontal direction can be reduced. Furthermore, the manufacturing accuracy of the thickness of the adhesive layer 24 in the direction perpendicular to the substrate 23 can be reduced, and a high coupling efficiency can be obtained without increasing the alignment accuracy.
[0123]
Further, in the present embodiment, even when a light control element such as an optical switch, a wavelength conversion element, or a polarization conversion element is provided in the central waveguide optical wiring 22, the two waveguide optical wirings 20 and 21 at both ends are made highly efficient. And loss due to insertion of the light control element can be reduced. In addition, since it is not necessary to manufacture the light control element integrally with the waveguide optical wiring 20 or 21, the degree of freedom of materials and manufacturing processes is improved, and a highly functional light control element can be realized.
[0124]
Further, even if the optical axes of the waveguide optical wirings 20 and 21 are shifted from the substrate 23, the two waveguide optical coupling elements 4 are provided, so that high coupling efficiency can be realized. This can be realized by providing one waveguide type optical coupling element between the waveguide optical wirings 20 and 21 even when the central waveguide optical wiring 22 is not provided.
[0125]
A seventh embodiment of the present invention will be described with reference to FIG. The basic structure of the optical wiring of this embodiment is the same as that of the sixth embodiment (see FIG. 8), and the waveguide type optical coupling element 4 has a shape with a length of 1 or less with respect to the diameter. This is the case.
[0126]
According to this optical wiring, when the deviation of the waveguide optical wirings 20, 21, and 22 is smaller than the core diameter, high optical coupling efficiency can be obtained, and at the same time, the length of the waveguide type optical coupling element 4 can be increased. Since it is short, the waveguide loss of the waveguide type optical coupling element 4 itself is reduced, and higher coupling efficiency can be obtained.
[0127]
An eighth embodiment of the present invention will be described with reference to FIG. In the optical wiring of the present embodiment, the waveguide optical wiring 21 and the waveguide optical wiring 25 which are light incident side elements are bonded on the substrate 23, and the light output side is located at a position where it is optically coupled to the waveguide optical wiring 25. A light emitting element module 1 as an element is arranged. The waveguide optical wiring 25 is provided with an optical deflection element 26 that deflects the guided light by 90 degrees. The light deflection element 26 is formed by forming a portion bent at 90 degrees in the core 25a and providing an air layer 27 outside the core 25a in the bent portion. A waveguide type optical coupling element 4 that optically couples the light emitting element module 1 and the waveguide optical wiring 25 and a waveguide type optical coupling element 4 that optically couples the waveguide optical wiring 25 and the waveguide optical wiring 21 are provided. It has been. The direction in which the light emitting element module 1 and the waveguide optical wiring 25 are optically coupled is substantially perpendicular to the direction in which the waveguide optical wiring 25 and the waveguide optical wiring 21 are optically coupled.
[0128]
In this optical wiring, the laser light 13 a emitted from the light emitting element module 1 perpendicular to the direction of the substrate 23 is coupled to the core 25 a of the waveguide optical wiring 25 in the direction perpendicular to the substrate 23 by the waveguide type optical coupling element 4. . The guided light incident on the core 25a of the waveguide optical wiring 25 is deflected in the traveling direction in parallel with the substrate 23 by the optical deflecting element 26, and further exits from the right end face and enters the waveguide type optical coupling element 4. Then, the light enters from the waveguide type optical coupling element 4 to the core 21 a of the waveguide optical wiring 21.
[0129]
A conventional optical deflection unit that deflects the traveling direction of guided light by 90 degrees is formed by processing a core layer by 45 degrees on the waveguide optical wiring by dry etching or dicing, and has a structure integrated with the waveguide optical wiring. On the other hand, according to the optical wiring of the present embodiment, the optical deflection element 26 is provided on the waveguide optical wiring 25 having a waveguide structure different from the horizontal waveguide optical wiring 21 on the substrate 23. Therefore, a large amount of the waveguide optical wiring 25 having the optical deflection element 26 can be manufactured with high accuracy. For this reason, higher deflection efficiency and lower cost optical wiring can be realized.
[0130]
On the other hand, by providing the waveguide optical wiring 21 and the waveguide optical wiring 25 separately, generally, the necessity of high-precision alignment and coupling loss occur between the waveguide optical wirings 21 and 25. . However, in the present embodiment, by providing the waveguide type optical coupling element 4, high coupling efficiency can be realized by simple alignment. As a result, the light emitting element module 1 that emits light in the direction perpendicular to the substrate 23 and the substrate 23 are horizontal. The optical waveguide 21 can be easily optically coupled with high efficiency. When a surface light emitting device such as a VCSEL is mounted on the surface, light is emitted in a direction perpendicular to the substrate 23, so that the surface light emitting device such as a VCSEL can be easily mounted.
[0131]
A ninth embodiment of the present invention will be described with reference to FIG. In the optical wiring of the present embodiment, reference numerals 31 and 32 are multichip modules provided with the light emitting element module 1 or the light receiving element module 2, and are provided on the photoelectric composite substrate 35 by solder bumps 33a, 33b, 33c, and 33d. Are connected to horizontal copper wirings 36a and 36b. Further, two waveguide optical wirings 25 each having an optical deflection element 26 and a waveguide optical wiring 37 that optically couples these waveguide optical wirings 25 are bonded on the photoelectric composite substrate 35. The multi-chip modules 31 and 32 and the waveguide optical wiring 25 and the waveguide optical wiring 25 and the waveguide optical wiring 37 are optically coupled by the waveguide type optical coupling element 4, respectively. The horizontal copper wirings 36a and 36b are connected by through-hole copper wirings 38a and 38b.
[0132]
In this optical wiring, electrical signals and power to the multichip modules 31 and 32 are transmitted through the photoelectric composite substrate 35 through the horizontal copper wirings 36a and 36b and the through-hole copper wirings 38a and 38b in the vertical direction. Transmission can be performed on the electric composite substrate 35 using the solder bumps 33a, 33b, 33c, and 33d. Furthermore, electrical signal transmission between the multichip modules 31 and 32 can also be realized by using these horizontal copper wirings 36a and 36b and through-hole copper wirings 38a and 38b.
[0133]
At this time, optical signal transmission between the multi-chip modules 31 and 32 is performed by guiding the light flux from the light-emitting element module 1 of the multi-chip module 31 to the waveguide optical wiring 25 having a waveguide structure provided with the optical deflection element 26. By optically coupling with the waveguide optical coupling element 4 and further optically coupling with the waveguide optical interconnection 25, the core 37a of the waveguide optical interconnection 37, and the waveguide optical coupling element 4, the light can be obtained with high efficiency and low alignment accuracy. The electric composite substrate 35 can be transmitted in the horizontal direction and transmitted as an optical signal. Further, the guided light as the optical signal traveling in the horizontal direction on the photoelectric composite substrate 35 is guided by the waveguide optical wiring 25 having a waveguide structure provided with the optical deflection element 26 different from the light emitting element module 1. It can be optically coupled to the light receiving element module 2 of another multichip module 32 and transmitted between the multichip modules 31 and 32.
[0134]
Further, the waveguide optical wiring 25 having a waveguide structure provided with the optical deflecting element 26 may be configured to penetrate the photoelectric composite substrate 35, and the optical wiring may be provided below the photoelectric composite substrate 35. . Thereby, the upper side of the optoelectric composite substrate 35 can be separated vertically from the electrical mounting part and the lower side from the optical wiring part, and the optical wiring can be provided after the electrical mounting process by reflow. Therefore, it is possible to realize an inexpensive waveguide optical wiring with low loss.
[0135]
A tenth embodiment of the present invention will be described with reference to FIG. The present embodiment relates to a method for manufacturing the optical wiring described above. FIGS. 12A and 12B show low elasticity in which a waveguide type optical coupling element is formed between the light emitting element module 1 which is a light emitting side element and the lens 3 which is a part of the light incident side element 14. The process of providing the liquid material 41 used as the precursor material of a body material is shown. The liquid material 41 is stored in the dispenser 42, and the tip of the dispenser 42 is disposed or closely adhered to the vicinity of the glass window 8 of the light emitting element module 1 (FIG. 12A), and the liquid material 41 in the dispenser 42 is dropped. Then, the dispenser 42 is moved in the direction of the lens 3, and finally, the tip of the dispenser 42 moved in the direction of the lens 3 is disposed or brought into close contact with the lens 3 (FIG. 12B). Thereby, the liquid material 41 adhering to the glass window 8 in the first stage extends toward the lens 3 due to its own viscosity and surface tension as the dispenser 42 moves, and between the glass window 8 and the lens 3. A crosslinked structure is formed.
[0136]
Thereafter, the liquid material 41 having a crosslinked structure is irradiated with ultraviolet rays by an ultraviolet lamp 43 (FIG. 12C). By irradiation with the ultraviolet rays, the liquid material 41 is chemically changed to a low-elastic rubber state, and the waveguide type optical coupling element 4 is formed (FIG. 12D).
[0137]
As a result of this chemical change, it is not necessary to be in a rubber state, it may be in a gel state, and can be realized by mixing a monomer material having acrylate or methacrylate and a photoinitiator in the liquid material 41. A thermal polymerization initiator may be used. Further, as the liquid material 41, a physical gel that is in a sol state at a high temperature and a gel state at a low temperature, or a material that gels due to a change in the concentration of a solvent or contained ions may be used. Further, a siloxane material, an epoxy material, or an ethylene oxide material using a catalyst can be used.
[0138]
Further, this cross-linking structure can be adjusted not only by the material composition of the liquid material 41 but also by the viscosity, the dropping amount, the dropping moving speed, the interface characteristics of the glass window 8 and the lens 3 of the light emitting element module 1 and the viscosity, and has an appropriate configuration A cross-linked structure can be realized.
[0139]
An eleventh embodiment of the present invention will be described with reference to FIG. The present embodiment relates to a method for manufacturing the optical wiring described above. 13 (a) to 13 (d) of the manufacturing method of the present embodiment are the same as FIGS. 12 (a) to 12 (d) of the tenth embodiment, and the waveguide formed thereafter. The type optical coupling element 4 is made highly elastic by performing a thermosetting treatment (FIG. 13E). By applying this high elasticity treatment, the mechanical strength and reliability of the waveguide type optical coupling element 4 are improved.
[0140]
A twelfth embodiment of the present invention will be described with reference to FIG. The present embodiment relates to a method for manufacturing the optical wiring described above. FIGS. 14A to 14D of the manufacturing method of the present embodiment are the same as FIGS. 12A to 12D of the tenth embodiment, and then the formed waveguide. A coating layer 15 is formed from a highly elastic material around the optical coupling element 4 (FIG. 14E). This coating layer 15 is the same as the coating layer 15 described in the second embodiment (see FIG. 4). The coating layer 15 is formed by performing hydrophilic silane coupling on the formed waveguide type optical coupling element 4 with steam, and thereafter dropping a hydrophilic material onto the waveguide type optical coupling element 4. By doing so, the coating layer 15 which covers the waveguide type optical coupling element 4 can be formed with a film thickness corresponding to the viscosity of the hydrophilic material. This hydrophilic material contains an acrylate monomer in advance, and the formed coating layer 15 is gelled and rubberized to make it a hard material, so that it has relatively high elasticity relative to the inner low-elasticity material. It can be coated with a certain material.
[0141]
A thirteenth embodiment of the present invention will be described with reference to FIG. The present embodiment relates to a method for manufacturing the optical wiring 4 described above. FIG. 15A shows a process in which a hydrophilic coating film 51 is applied to the glass window 8 and the lens 3 which are locations where the waveguide type optical coupling element is optically coupled. The portions other than the portion where the hydrophilic coating film 51 is applied are previously hydrophobized with a silane coupling agent. Thereafter, the liquid material 41 serving as a precursor of the low-elastic material forming the waveguide type optical coupling element is dropped excessively by a dispenser (see FIG. 12). In the operation of dropping the liquid material 41, the liquid material 41 is first attached to the glass window 8 or the lens 3, and then the liquid material 41 is slowly dropped, whereby the dropped liquid material 41 has its own stickiness and surface tension. As a result, it gradually expands and eventually reaches the lens 3 or the glass window 8, and a cross-linking structure made of a large amount of the liquid material 41 is formed between the glass window 8 and the lens 3 (FIG. 15B). Thereafter, the whole or a light emitting element module 1 or the lens 3 is vibrated by an ultrasonic vibrator (not shown) to excite the fluid motion of the liquid material 41 and drop the excess of the liquid material 41. As a result, the remaining liquid material 41 has a cross-linked structure in which the central portion is thinned by its surface tension (FIG. 15C). Thereafter, the liquid material 41 having a crosslinked structure is irradiated with ultraviolet rays to reduce the liquid material 41 to form the waveguide type optical coupling element 4 (FIG. 15D).
[0142]
According to this manufacturing method, it is not necessary to move the dispenser between the glass window 8 and the lens 3, and the operation is simplified. Moreover, the waveguide type optical coupling element 4 can also be produced in a narrow gap where a dispenser cannot be inserted. As a method of exciting the fluid motion in the liquid material 41, it is effective to use a fan blower, a motor vibration device, or the like in addition to the ultrasonic vibrator.
[0143]
A fourteenth embodiment of the present invention will be described with reference to FIG. This embodiment relates to a method for manufacturing the above-described optical wiring. FIG. 16A shows a process in which a hydrophilic coating film 51 is applied to the glass window 8 and the lens 3 that are locations where the waveguide type optical coupling element is optically coupled. The portions other than the portion where the hydrophilic coating film 51 is applied are previously hydrophobized with a silane coupling agent. Further, the light emitting element module 1 and the lens 3 are arranged so as to have a short gap with respect to the optimum gap. Thereafter, an appropriate amount of a liquid material 41, which is a precursor of the low-elasticity material forming the waveguide type optical coupling element, is dropped by a dispenser (see FIG. 12), and the same process as in FIG. Then, a crosslinked structure made of a large amount of the liquid material 41 is formed between the glass window 8 and the lens 3 (FIG. 16B). After that, one of the light emitting element module 1 and the lens 3 is displaced in the separation direction by a piezo displacement machine (not shown) to obtain an appropriate gap. As a result, the liquid material 41 has a cross-linked structure in which the central portion is thinned by its surface tension (FIG. 16C). Thereafter, the liquid material 41 having a cross-linked structure is irradiated with ultraviolet rays to reduce the liquid material 41 to form the waveguide type optical coupling element 4 (FIG. 16D).
[0144]
When the light emitting element module 1 and the lens 3 are displaced, self-alignment by solder bumps may be used.
[0145]
【The invention's effect】
According to the waveguide type optical coupling element of the first aspect of the present invention, even when the optical axis of the light emitting side element and the optical axis of the light incident side element are shifted, the waveguide type optical coupling element is a low elastic material. Therefore, it is possible to deform according to the deviation, and high-precision alignment is not required when optically coupling the light emitting side element and the light incident side element, and the cost for optical coupling is eliminated. Can be reduced.
[0161]
Claim2According to the described invention, the claims1In the mounted waveguide type optical coupling element, since the coating layer made of a highly elastic material is provided in the periphery, the mechanical strength and reliability of the waveguide type optical coupling element can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an optical wiring according to a first embodiment of the present invention.
FIG. 2 is an explanatory view for explaining the action of spontaneously deflecting the optical axis of the waveguide type optical coupling element itself.
FIG. 3 is an explanatory diagram illustrating a comparative example in which a waveguide type optical coupling element is omitted from an optical wiring.
FIG. 4 is a schematic diagram showing an optical wiring according to a second embodiment of the present invention.
FIG. 5 is a schematic view showing an optical wiring according to a third embodiment of the present invention.
FIG. 6 is a schematic diagram showing an optical wiring according to a fourth embodiment of the present invention.
FIG. 7 is a schematic diagram showing an optical wiring according to a fifth embodiment of the present invention.
FIG. 8 is a schematic diagram showing an optical wiring according to a sixth embodiment of the present invention.
FIG. 9 is a schematic view showing an optical wiring according to a seventh embodiment of the present invention.
FIG. 10 is a schematic diagram showing an optical wiring according to an eighth embodiment of the present invention.
FIG. 11 is a schematic diagram showing an optical wiring according to a ninth embodiment of the present invention.
FIG. 12 is a schematic view showing the method of manufacturing the optical wiring according to the tenth embodiment of the present invention.
FIG. 13 is a schematic view showing a method of manufacturing an optical wiring according to the eleventh embodiment of the present invention.
FIG. 14 is a schematic view showing the method of manufacturing the optical wiring in the twelfth embodiment of the present invention.
FIG. 15 is a schematic view showing the method of manufacturing the optical wiring in the thirteenth embodiment of the present invention.
FIG. 16 is a schematic view showing a method of manufacturing an optical wiring according to a fourteenth embodiment of the present invention.
FIG. 17 is a cross-sectional view showing an example of a conventional optical wiring.
[Explanation of symbols]
1 Output side element
4 Waveguide type optical coupling element
4a, 4b Contact fixing part
14 Acquisition side element
15 Coating layer
16 Waveguide type optical coupling element
17 Waveguide optical wiring
18 Waveguide optical wiring
20 Incident side element
21 Output side element
22 Waveguide optical wiring
26 Light deflection element
35 substrates
36a, 36b Electrical wiring
41 Liquid material

Claims (2)

In a waveguide type optical coupling device using a waveguide composed of a core and a clad that optically couples a light emitting side device that emits light and a light incident side device that enters light, the waveguide type optical coupling device has an elastic constant. A waveguide-type optical coupling element that is made of a low-elasticity material that is 10 ² dyn / cm ³ or more and 10 ⁸ dyn / cm ³ or less and that can be self-supported in the state of the low-elasticity material. The waveguide type optical coupling element according to claim 1, wherein a coating layer made of a high elastic material that is relatively highly elastic with respect to the low elastic material is provided around.

Images