Polymer optical waveguide and optical waveguide component

Abstract

To provide a polymer optical waveguide and optical waveguide component, which reduce inter-core crosstalk.SOLUTION: A polymer optical waveguide provided herein comprises multiple cores arranged in an imaginary plane, and a cladding provided around the multiple cores. The cladding has a groove formed between a pair of adjacent cores of the multiple cores, the groove having a first wall surface extending along the pair of cores and inclined from an imaginary surface perpendicular to the imaginary plane.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] TECHNICAL FIELD This disclosure relates to polymer optical waveguides and optical waveguide components. [Background technology]

[0002] In conventional multi-core polymer waveguides, the pitch between the input and output ends of the cores may vary, in which case the cores have a curved shape. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-014964 [Patent Document 2] International Publication No. 2019 / 111401 Summary of the Invention [Problem to be solved by the invention]

[0004] If the core has a curved shape, there is a risk that light propagating through the core will leak and cause crosstalk.

[0005] The present disclosure aims to provide polymer optical waveguides and optical waveguide components that can reduce crosstalk between cores. [Means for solving the problem]

[0006] According to one embodiment of the present disclosure, there is provided a polymer optical waveguide having a plurality of cores arranged on an imaginary plane and a cladding provided around the plurality of cores, wherein a groove is formed in the cladding located between two adjacent cores among the plurality of cores, the groove having a first wall surface extending along the two cores, and the first wall surface being inclined from an imaginary plane perpendicular to the imaginary plane. [Effects of the Invention]

[0007] According to the present disclosure, crosstalk between cores can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a top view illustrating the polymer optical waveguide according to the first embodiment. [Figure 2] 1 is a cross-sectional view illustrating a polymer optical waveguide according to a first embodiment. [Figure 3] 2A to 2C are cross-sectional views illustrating a method for manufacturing the polymer optical waveguide according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view illustrating a polymer waveguide according to a modified example of the first embodiment. [Figure 5] FIG. 10 is a top view illustrating an optical waveguide component according to a second embodiment. [Figure 6] FIG. 10 is a cross-sectional view illustrating an optical waveguide component according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description may be omitted.

[0010] (First embodiment) A first embodiment will be described. The first embodiment relates to a polymer optical waveguide.

[0011] [Structure of polymer optical waveguide] The structure of the polymer optical waveguide according to the first embodiment will be described. Fig. 1 is a top view illustrating the polymer optical waveguide according to the first embodiment. Fig. 2 is a cross-sectional view illustrating the polymer optical waveguide according to the first embodiment. Fig. 2(a) corresponds to the cross-sectional view taken along line IIa-IIa in Fig. 1, and Fig. 2(b) corresponds to the cross-sectional view taken along line IIb-IIb in Fig. 1.

[0012] As shown in FIGS. 1 and 2, the polymer optical waveguide 1 according to the first embodiment has a cladding 10 and a plurality of cores 20. The cladding 10 is provided around the plurality of cores 20. The cladding 10 has a first cladding layer 11 and a second cladding layer 12. The first cladding layer 11 and the second cladding layer 12 are stacked on top of each other. The first cladding layer 11 has a first main surface 16. The second cladding layer 12 has a second main surface 17 in contact with the first main surface 16 and a third main surface 18 opposite to the second main surface 17.

[0013] In this embodiment, for convenience, the second cladding layer 12 side is referred to as the upper side or one side, and the opposite side is referred to as the lower side or other side, with respect to the first cladding layer 11. The upper surface of each part is referred to as the one side or upper surface, and the lower surface is referred to as the other side or lower surface. However, the polymer optical waveguide 1 can be used upside down or positioned at any angle.

[0014] The multiple cores 20 are arranged on an imaginary plane 25. The imaginary plane 25 includes the first principal surface 16. The second cladding layer 12 is provided on the first principal surface 16 and covers the multiple cores 20. The multiple cores 20 are sandwiched between the first cladding layer 11 and the second cladding layer 12. Each of the multiple cores 20 has an input end 21 and an output end 22. For example, among the multiple cores 20, the input ends 21 are arranged at equal intervals of 50 μm, and the output ends 22 are arranged at equal intervals of 250 μm. In a plan view perpendicular to the imaginary plane 25, each of the multiple cores 20 has a curved shape with one inflection point between the input end 21 and the output end 22. In a plan view, the curvatures of the multiple cores 20 differ, but the curved sides are the same.

[0015] The material of the first cladding layer 11 is, for example, an organic resin such as an epoxy resin or a polyimide resin, etc. The thickness of the first cladding layer 11 is, for example, about 10 μm to 30 μm.

[0016] The material of the core 20 is, for example, an organic resin such as an epoxy resin or a polyimide resin. For example, the cross section of the core 20 perpendicular to the extension direction is rectangular. To obtain a single-mode optical waveguide, the core 20 may have a very small cross section. For example, the width of the core 20 is 5 μm to 10 μm, and the height is 5 μm to 10 μm.

[0017] The material of the second cladding layer 12 is, for example, an organic resin such as an epoxy resin or a polyimide resin, etc. The thickness of the second cladding layer 12 is, for example, about 10 μm to 30 μm.

[0018] In the polymer optical waveguide 1, the refractive index of the core 20 is higher than the refractive index of the first cladding layer 11 and the second cladding layer 12.

[0019] The cladding 10 has a groove 30 formed between two adjacent cores 20 among the multiple cores 20. The groove 30 penetrates the second cladding layer 12 and the first cladding layer 11. For example, air is present in the groove 30. The width of the groove 30 is, for example, approximately 10 μm to 30 μm. For example, the groove 30 is along the portion between the input end 21 and the inflection point of the two adjacent cores 20. The groove 30 has wall surfaces 31 and 32 extending along the two cores 20. The wall surfaces 31 and 32 face each other. The groove 30 is tapered. The wall surfaces 31 and 32 are inclined from an imaginary plane 35 perpendicular to the imaginary plane 25. For example, the wall surfaces 31 and 32 are inclined in opposite directions relative to the imaginary plane 35. The angle θ1 between the imaginary plane 35 and the wall surface 31 is approximately 7°. The interior angle θ2 between the wall surface 31 and the second main surface 17 of the second cladding layer 12 is an acute angle, and the interior angle θ3 between the wall surface 31 and the third main surface 18 of the second cladding layer 12 is an obtuse angle. The angle between the imaginary plane 35 and the wall surface 32 is approximately 7°. The interior angle between the wall surface 32 and the second main surface 17 of the second cladding layer 12 is an acute angle, and the interior angle between the wall surface 32 and the third main surface 18 of the second cladding layer 12 is an obtuse angle. The wall surface 31 is an example of a first wall surface, and the wall surface 32 is an example of a second wall surface.

[0020] [Method for manufacturing polymer optical waveguides] A method for manufacturing the polymer optical waveguide 1 will now be described. Figure 3 is a cross-sectional view illustrating a method for manufacturing the polymer optical waveguide according to the first embodiment.

[0021] 3(a), an intermediate structure 41 is formed having a cladding 10 and a plurality of cores 20. Specifically, the plurality of cores 20 are formed on a first cladding layer 11, and a second cladding layer 12 is formed on the first cladding layer 11 and the plurality of cores 20. In the intermediate structure 41, the cladding 10 is provided around the plurality of cores 20.

[0022] Next, as shown in FIG. 3(b), a plurality of grooves 30 are formed in the intermediate structure 41. To form the grooves 30, laser light 50 is irradiated onto the third main surface 18 of the second cladding layer 12. As the laser light 50, for example, excimer laser light is used. By irradiating the laser light 50, the grooves 30 having wall surfaces 31 and 32 are formed. When the excimer laser light serving as the laser light 50 is irradiated perpendicularly onto the third main surface 18, the angle between an imaginary plane 35 and the wall surface 31 and the angle between the imaginary plane 35 and the wall surface 32 are both approximately 7°.

[0023] In this manner, the polymer optical waveguide 1 according to the first embodiment can be manufactured.

[0024] In the polymer optical waveguide 1, light input to the input end 21 propagates through the core 20 and is output from the output end 22. Because the core 20 is curved, when light propagates through the core 20, the light leaks along the tangent of the core 20, which can result in leakage light L, as shown in Figures 1 and 2(b). When the leakage light L reaches another core 20, crosstalk occurs. Crosstalk can cause degradation of signal quality and erroneous transmission. Figure 2(a) shows a cross section perpendicular to the extension direction of the groove 30, and Figure 2(b) shows a cross section parallel to the propagation direction of the leakage light L.

[0025] In this embodiment, a groove 30 having wall surfaces 31 and 32 is formed in the cladding 10, and the wall surfaces 31 and 32 are inclined with respect to an imaginary plane 35. Therefore, the leaked light L travels parallel to the imaginary plane 25 within the cladding 10, is refracted at the wall surface 31 so as to move away from the imaginary plane 25, and travels within the groove 30. The leaked light L that travels within the groove 30 is refracted at the wall surface 32 and enters the cladding 10, but does not reach the core 20. Therefore, the polymer optical waveguide 1 can reduce crosstalk between the cores 20 due to the leaked light L.

[0026] The grooves 30 do not need to be formed over the entire space between two adjacent cores 20. For example, they are preferably formed in locations where leakage light L is likely to occur and where two adjacent cores 20 are close to each other. In other words, they are preferably formed near locations where the curvature of the cores 20 is large and where the distance between two adjacent cores 20 is small.

[0027] (Modification of the first embodiment) The shape of the groove 30 is not limited to the above. Fig. 4 is a cross-sectional view illustrating a polymer waveguide according to a modified example of the first embodiment.

[0028] In a polymer optical waveguide 1A according to a modification of the first embodiment, the groove 30 is formed in an inverse tapered shape, as shown in Fig. 4. That is, the interior angle between the wall surface 31 and the second main surface 17 of the second cladding layer 12 is an obtuse angle, and the interior angle between the wall surface 31 and the third main surface 18 of the second cladding layer 12 is an acute angle. Also, the interior angle between the wall surface 32 and the second main surface 17 of the second cladding layer 12 is an obtuse angle, and the interior angle between the wall surface 32 and the third main surface 18 of the second cladding layer 12 is an acute angle.

[0029] In the polymer optical waveguide 1A as well, crosstalk between the cores 20 can be reduced.

[0030] The angle between wall surface 31 and imaginary surface 35 and the angle between wall surface 32 and imaginary surface 35 do not have to be equal. In other words, the angle between wall surface 31 and imaginary surface 35 may be larger than the angle between wall surface 32 and imaginary surface 35, or may be smaller than the angle between wall surface 32 and imaginary surface 35.

[0031] The angle between imaginary plane 35 and wall surface 31 and the angle between imaginary plane 35 and wall surface 32 are not limited. In order to more reliably prevent leakage light L generated in one core 20 from reaching other cores 20, the angle between imaginary plane 35 and wall surface 31 and the angle between imaginary plane 35 and wall surface 32 are preferably 3° or greater. As described above, when excimer laser light is irradiated perpendicularly to third main surface 18 as laser light 50, the angle between imaginary plane 35 and wall surface 31 and the angle between imaginary plane 35 and wall surface 32 are both approximately 7°. Taking into account a slight deviation from 7°, the angle between imaginary plane 35 and wall surface 31 and the angle between imaginary plane 35 and wall surface 32 may be 4° or greater and 10° or less, 5° or greater and 9° or less, or 6° or greater and 8° or less.

[0032] (Second embodiment) A second embodiment will be described. The second embodiment relates to an optical waveguide component having the polymer optical waveguide according to the first embodiment. Fig. 5 is a top view illustrating an optical waveguide component according to the second embodiment. Fig. 6 is a cross-sectional view illustrating an optical waveguide component according to the second embodiment.

[0033] As shown in FIGS. 5 and 6, the optical waveguide component 2 according to the second embodiment includes a substrate 61, the polymer optical waveguide 1 according to the first embodiment, an optical semiconductor element 62, and a control element 63. The substrate 61 is, for example, a printed wiring board. The polymer optical waveguide 1 is provided on the substrate 61. The optical semiconductor element 62 and the control element 63 are mounted on the substrate 61. The optical semiconductor element 62 is configured using silicon photonics and includes, for example, a laser diode. The optical semiconductor element 62 is optically coupled to the polymer optical waveguide 1. The control element 63 controls the optical semiconductor element 62.

[0034] The optical waveguide component 2 according to the second embodiment has the polymer optical waveguide 1, and therefore can reduce crosstalk between the cores 20 due to leaked light.

[0035] Although the preferred embodiments have been described in detail above, the present disclosure is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims. [Explanation of symbols]

[0036] 1.1A Polymer Optical Waveguide 2. Optical waveguide components 10 Clad 11 First cladding layer 12 Second cladding layer 16 First main surface 17 Second main surface 18 Third main surface 20 cores 25 Virtual Plane 30 grooves 31, 32 Wall 35 Virtual Surface 50 Laser light 61 PCB

Claims

1. Multiple cores arranged on a virtual plane, a cladding disposed around the cores; and a groove is formed in the cladding, the groove being located between two adjacent cores among the plurality of cores; The groove has a first wall surface extending along the two cores, The polymer optical waveguide, wherein the first wall surface is inclined from an imaginary plane perpendicular to the imaginary plane.

2. the groove extends along the two cores and has a second wall surface opposite to the first wall surface; The polymer optical waveguide according to claim 1 , wherein the second wall surface is inclined from the imaginary plane.

3. The polymer optical waveguide according to claim 2 , wherein the first wall surface and the second wall surface are inclined in opposite directions relative to the imaginary plane.

4. 4. The polymer optical waveguide according to claim 2, wherein the angle between the imaginary plane and the second wall surface is 3 degrees or more.

5. 4. The polymer optical waveguide according to claim 1, wherein the angle between the imaginary plane and the first wall surface is 3 degrees or more.

6. The cladding is a first cladding layer having a first major surface; a second cladding layer provided on the first principal surface; and the imaginary plane includes the first main surface, The polymer optical waveguide according to claim 1 , wherein the plurality of cores are sandwiched between the first cladding layer and the second cladding layer.

7. the groove penetrates the second cladding layer; The second cladding layer is a second main surface in contact with the first main surface; a third major surface opposite the second major surface; and an interior angle between the first wall surface and the second main surface is an acute angle; The polymer optical waveguide of claim 6 , wherein an interior angle between the first wall surface and the third main surface is an obtuse angle.

8. A substrate; a polymer optical waveguide according to any one of claims 1 to 3 provided on the substrate; An optical waveguide component having:

Images