Optical waveguide package and light emitting device

Abstract

The optical waveguide package of the present application has a substrate (1) having a first surface, and an optical waveguide layer (5) having a cladding layer (3) on the first surface and a core (4) in the cladding layer. The substrate (1) has a first portion (31) and a second portion (32) in contact with the cladding layer (3), the second portion having a higher adhesion strength to the cladding layer than the first portion.

Description

Technical Field

[0001] This disclosure relates to optical waveguide packages and light-emitting devices. Background Technology

[0002] Patent document 1 describes an example of prior art.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 4215764 Summary of the Invention

[0006] The optical waveguide package disclosed herein includes:

[0007] A substrate having a first side;

[0008] The optical waveguide layer has a cladding layer located on the first surface and a core located within the cladding layer.

[0009] The substrate has a first portion and a second portion that are in contact with the cladding layer.

[0010] The second part has a higher bonding strength with respect to the cladding than the first part has a higher bonding strength with respect to the cladding.

[0011] The light-emitting device disclosed herein includes: the optical waveguide package and a light-emitting element connected to the optical waveguide package. Attached Figure Description

[0012] The purpose, features, and advantages of this disclosure become more apparent from the following detailed description and accompanying drawings.

[0013] Figure 1 This is an exploded perspective view showing a light-emitting device having the optical waveguide package according to the first embodiment of the present disclosure.

[0014] Figure 2 yes Figure 1 The perspective view of the light-emitting device shown is omitted, omitting the sealing cover.

[0015] Figure 3 From Figure 1 A cross-sectional view of the light-emitting device observed along section line III-III.

[0016] Figure 4 It is an enlarged cross-sectional view of a portion near the recess of the light-emitting device.

[0017] Figure 5 This is an electron microscope image of the surface of substrate 1.

[0018] Figure 6AThis is an enlarged view of a portion of the light-emitting device according to the second embodiment of this disclosure, and a cross-sectional view of a portion of the light-emitting element viewed from the side.

[0019] Figure 6B This is an enlarged view of a portion of the light-emitting device according to the second embodiment of this disclosure, and a top view of a portion of the substrate viewed from above.

[0020] Figure 7A This is an enlarged view of a portion of the light-emitting device according to the third embodiment of this disclosure, and a cross-sectional view of a portion of the light-emitting element viewed from the side.

[0021] Figure 7B This is an enlarged view of a portion of the light-emitting device according to the third embodiment of this disclosure, and a top view of a portion of the substrate viewed from above.

[0022] Figure 8A This is an enlarged view of a portion of the light-emitting device according to the fourth embodiment of this disclosure, and a cross-sectional view of a portion of the light-emitting element viewed from the side.

[0023] Figure 8B This is an enlarged view of a portion of the light-emitting device according to the fourth embodiment of this disclosure, and a top view of a portion of the substrate viewed from above.

[0024] Figure 9A This is an enlarged view of a portion of the light-emitting device according to the fifth embodiment of this disclosure, and a cross-sectional view of a portion of the light-emitting element viewed from the side.

[0025] Figure 9B This is an enlarged view of a portion of the light-emitting device according to the fifth embodiment of this disclosure, and is a top view of a portion of the substrate viewed from above.

[0026] Figure 10A This is an enlarged view of a portion of the light-emitting device according to the sixth embodiment of this disclosure, and a cross-sectional view of a portion of the light-emitting element viewed from the side.

[0027] Figure 10B This is an enlarged view of a portion of the light-emitting device according to the sixth embodiment of this disclosure, and is a top view of a portion of the substrate viewed from above.

[0028] Figure 11A This is an enlarged view of a portion of the light-emitting device according to the seventh embodiment of this disclosure, and a cross-sectional view of a portion of the light-emitting element viewed from the side.

[0029] Figure 11B This is an enlarged view of a portion of the light-emitting device according to the seventh embodiment of this disclosure, and is a top view of a portion of the substrate viewed from above.

[0030] Figure 12AThis is an enlarged view of a portion of the light-emitting device according to the eighth embodiment of this disclosure, and a cross-sectional view of a portion of the light-emitting element viewed from the side.

[0031] Figure 12B This is an enlarged view of a portion of the light-emitting device according to the eighth embodiment of this disclosure, and is a top view of a portion of the substrate viewed from above.

[0032] Figure 13A This is an enlarged view of a portion of the light-emitting device according to the ninth embodiment of this disclosure, and a cross-sectional view of a portion of the light-emitting element viewed from the side.

[0033] Figure 13B This is an enlarged view of a portion of the light-emitting device according to the ninth embodiment of this disclosure, and is a top view of a portion of the substrate viewed from above. Detailed Implementation

[0034] In the structure of the optical waveguide package and the light-emitting device using the same described in Patent Document 1, a polymer waveguide substrate is included. This polymer waveguide substrate has, on the same substrate, a first region having an optical waveguide composed of or primarily composed of a polymer layer, and a second region not having an optical waveguide. On the surface of this substrate, an adhesive layer for improving the adhesion or bonding between the polymer layer and the substrate is provided in the first and second regions.

[0035] At this point, the adhesive layer in region 1 is not etched, but the adhesive layer in region 2 is etched, and a polymer layer is formed on the entire surface of the substrate to fabricate the optical waveguide. Then, the polymer layer at the boundary between region 1 and region 2 is cut off, and the polymer layer in region 2 is peeled off from the substrate and removed, thereby exposing the electrodes.

[0036] The adhesive layer comprises any one or a combination of polyimide silicone resin, fluorine-free polyimide resin, organoaluminum compound, organozirconia compound, and organotitanium compound. Thus, in the structure described in Patent Document 1, the waveguide is bonded to the substrate via the adhesive layer, thereby reducing substrate peeling from the waveguide and maintaining sufficient practical adhesive strength over a long period.

[0037] However, in the structure described in Patent Document 1, the waveguide and substrate are bonded together with a high adhesive strength via an adhesive layer, thus lacking a portion capable of mitigating the thermal stress generated by the light emission of the light-emitting element. Therefore, the adhesive layer sandwiched between the optical waveguide and the substrate results in high overall thermal stress, which, through repeated generation, could potentially lead to the substrate peeling off from the optical waveguide. Therefore, there is a need for further mitigation of thermal stress and a reduction in the peeling off of the optical waveguide.

[0038] Hereinafter, embodiments of the light-emitting device of this disclosure will be described with reference to the accompanying drawings.

[0039] (First Embodiment)

[0040] Figure 1 This is an exploded perspective view showing a light-emitting device equipped with the optical waveguide package according to the first embodiment of the present disclosure. Figure 2 yes Figure 1 The perspective view of the light-emitting device shown is omitted, omitting the sealing cover. Figure 3 From Figure 1 A cross-sectional view of the light-emitting device observed along section line III-III.

[0041] The optical waveguide package 50 of this embodiment includes: a substrate 1, an optical waveguide layer 5 having a cladding layer 3 located on the upper surface 2 of the substrate 1 and a core 4 located within the cladding layer 3. The cladding layer 3 has: an upper surface 6, a lower surface 7, and a recess 8 extending from the upper surface 6 toward the substrate 1 to the lower surface 7. The upper surface 2 of the substrate 1 faces the recess 8, and a sealing cover 11 is stacked on the upper surface 6 of the cladding layer 3 to cover the recess 8. Between the lower surface 11a of the sealing cover 11 and the upper surface 2 of the substrate 1, a receiving space for accommodating the light-emitting element 10 is defined by the inner wall surface 13 of the cladding layer 3 facing the recess 8.

[0042] In the optical waveguide package 50 of this embodiment, there are multiple (three in this embodiment) recesses 8 that respectively accommodate light-emitting elements 10, and each light-emitting element 10 is included to form a light-emitting device 20. A laser diode or the like is used as the light-emitting element 10. The optical waveguide layer 5 is formed by integrally bonding the core 4 and the cladding 3. The substrate 1 can be formed by stacking multiple dielectric layers. The light-emitting elements 10 can be mounted according to the markings recorded on the upper surface 2 of the substrate 1 and by passive alignment using image recognition.

[0043] Substrate 1 may be a ceramic wiring substrate in which the dielectric layer contains a ceramic material. Examples of ceramic materials used in ceramic wiring substrates include alumina sintered bodies, mullite sintered bodies, silicon carbide sintered bodies, aluminum nitride sintered bodies, and glass-ceramic sintered bodies. When substrate 1 is a ceramic wiring substrate, the dielectric layer is provided with connection pads for electrical connections between the light-emitting element and the light-receiving element and external circuitry, internal wiring conductors, external connection terminals, etc.

[0044] The material of substrate 1 can be, for example, an organic wiring substrate in which the dielectric layer contains an organic material. Organic wiring substrates include, for example, printed wiring substrates, multilayer wiring substrates, and flexible wiring substrates. Examples of organic materials used in organic wiring substrates include epoxy resin, polyimide resin, polyester resin, acrylic resin, phenolic resin, and fluoropolymer resin.

[0045] The waveguide layer 5 can be, for example, glass such as quartz, resin, etc. The lower surface 11a of the sealing cover 11 is bonded to the upper surface 2 of the substrate 1 by a bonding layer 55 such as metal or glass, thus sealing the recess 8 hermetically. As a result, the recess 8 has high gas barrier properties, blocking the intrusion of gases such as air with different refractive indices and foreign objects from the outside. The sealing cover 11 can, for example, contain the same material as the cladding layer 3.

[0046] In the optical waveguide layer 5, the materials constituting the core 4 and the cladding 3 can both be glass or resin, or one can be glass and the other resin. In this case, the core 4 and the cladding 3 have different refractive indices, with the core 4 having a higher refractive index than the cladding 3. Total internal reflection is achieved by utilizing this difference in refractive index. That is, if the path is made of a material with a high refractive index and surrounded by a material with a low refractive index, light can be confined within the core 4, which has a high refractive index.

[0047] The light-emitting device of the embodiment includes a common structure in which three light-emitting elements emitting red (R) light, green (G) light, and blue (B) light are respectively housed in the recess 8 and mounted on the upper surface 2 of the substrate 1. Therefore, the structure of one of the three light-emitting elements 10 will be described here. In addition, the suffixes a, b, and c may be omitted for the reference numerals corresponding to the above-described parts unless special identification is required. The core 4 is configured to connect the multiple incident surfaces 4a, 4b, and 4c to one exit surface 42 via a wave-combining section 43 that converges the multiple segmented paths 41a, 41b, and 41c with the incident surfaces 4a to 4c as one end, and a unifying path 44 that connects the multiple incident surfaces 4a, 4b, and 4c to one exit surface 42 with the exit surface 42 as one end.

[0048] Multiple condenser lenses 45 are provided corresponding to multiple incident end faces 4a, 4b, and 4c. The condenser lenses 45 are arranged opposite to the incident end faces 4a, 4b, and 4c of the core 4. The optical axis of the condenser lenses 45 is arranged on the central axis of the incident end faces 4a, 4b, and 4c.

[0049] The red (R) light, green (G) light, and blue (B) light emitted from each of the light-emitting elements 10 are incident from the incident end faces 4a, 4b, and 4c onto the dividing paths 41a, 41b, and 41c, and then focused and emitted through the focusing lens 45 via the combining section 43 and the unifying path 44.

[0050] The condenser lens 45 is, for example, a dry convex lens with a plane incident surface and a convex exit surface. The waveguide layer 5, the light-emitting element 10 and the condenser lens 45 are assembled such that the optical axes of each of the segmented paths 41a, 41b, and 41c are aligned with the center of the light-emitting part of each light-emitting element 10.

[0051] Figure 4It is an enlarged cross-sectional view of a portion near the recess of the light-emitting device. Figure 5 This is an electron microscope image of the surface of substrate 1. Substrate 1 includes a first part 31 and a second part 32. The first part 31 is a low-density bonding region where the upper surface 2 is in contact with the cladding layer 3. The second part 32 is a high-density bonding region located within the first part 31, where the upper surface 2 is exposed from the first part 31, and is configured to be in contact with the cladding layer 3 and have a higher bonding strength relative to the cladding layer 3 than the first part 31.

[0052] Part 1, 31, includes, for example, aluminum nitride (AlN), boron nitride (BN), zirconium carbide (ZrC), diamond (C), and fluorine resins. Part 2, 32, includes alumina (Al₂O₃), zirconium oxide (ZrO₂), magnesium oxide (MgO), titanium dioxide (TiO₂), barium titanate (BaTiO₃), quartz glass, silicon dioxide (SiO₂), and silicon resins, the proportions of which can be appropriately selected by combining them with other conditions.

[0053] By configuring the substrate 1 to include a first part 31 and a second part 32, the adhesion strength between the second parts 32 and between the first part 31 and the second part 32 can be enhanced, reducing the decrease in thermal conductivity caused by peeling due to thermal expansion. Furthermore, the adhesion strength can be evaluated, for example, by measuring the amount of residue of the first part 31 and the second part 32 relative to the cladding 3, the residual area, and the residual area relative to the original adhesive area when stretched from the lower surface of the substrate 1 or the upper surface of the cladding 3, at the boundary between the lower surface of the cladding 3 and the upper surface 2 of the substrate 1.

[0054] (Second Implementation)

[0055] Figure 6A , Figure 6B This is an enlarged view of a portion of the light-emitting device according to the second embodiment of this disclosure. Figure 6A This is a cross-sectional view of a portion of the light-emitting element viewed from the side. Figure 6B This is a top view of a portion of the substrate 1 as seen from above. Furthermore, the same reference numerals are used for portions corresponding to the embodiments described above, and repeated descriptions are omitted. The upper surface 2 of the substrate 1 is made mirror-like through a grinding process or the like. This improves the flatness of the interface between the substrate 1 and the optical waveguide layer 5 through grinding, thereby improving the planarity of the optical waveguide layer 5 formed thereon and increasing light propagation efficiency. Furthermore, by making the upper surface 2 of the substrate 1 mirror-like, light leakage caused by reflection can be reduced. The higher the reflectivity of the substrate 1, the greater the reduction rate. A mirror-like surface is obtained by processing the surface of a metal or coated surface into a mirror-like surface that reflects objects.

[0056] (Third Implementation)

[0057] Figure 7A , Figure 7B This is an enlarged view of a portion of the light-emitting device according to the third embodiment of this disclosure. Figure 7A This is a cross-sectional view of a portion of the light-emitting element viewed from the side. Figure 7B This is a top view of a portion of the substrate 1 viewed from above. Furthermore, the same reference numerals are used for portions corresponding to the embodiments described above, and repeated descriptions are omitted. The second part 32 includes granular bodies 33, which have a main portion and protrusions 33a extending from and continuously disposed with the main portion. Granular bodies 33 refer to granular objects dispersed within the first part 31. The shape of the main portion can be, for example, a cylinder, cone, frustum of a cone, prism, pyramid, frustum of a pyramid, sphere, ellipsoid, etc. Protrusions 33a refer to portions where smaller particles integrally protrude from the surface of the main portion. By including the granular bodies 33 with protrusions 33a in the second part 32, the bonding strength between the second parts 32 and between the first part 31 and the second part 32 can be enhanced, reducing the decrease in thermal conductivity caused by peeling due to thermal expansion. For example, the radius of curvature of the protrusion 33a can be about 0.01 to 5 μm, and the shape can be, for example, a cylinder, a cone, a frustum of a cone, a prism, a pyramid, a frustum of a pyramid, a sphere, an ellipsoid, etc.

[0058] (Fourth implementation)

[0059] Figure 8A , Figure 8B This is an enlarged view of a portion of the light-emitting device according to the fourth embodiment of this disclosure. Figure 8A This is a cross-sectional view of a portion of the light-emitting element viewed from the side. Figure 8B This is a top view of a portion of the substrate 1 as seen from above. Furthermore, the same reference numerals are used for portions corresponding to the embodiments described above, and repeated descriptions are omitted. The second part 32 includes a plurality of columnar bodies 34 extending in the thickness direction of the substrate 1. By including such a plurality of columnar bodies 34 in the second part 32, the area of ​​the bonding interface with the first part 31 can be increased, thereby increasing the bonding strength between the waveguide layer 5 and the wiring layers such as electrodes, and the substrate 1 as a whole. Furthermore, since the number of interfaces passing from the waveguide layer 5, the wiring layers such as electrodes, to the back surface of the substrate 1 is reduced, heat dissipation can be effectively achieved. A columnar body is a columnar object, which, when viewed from above, is, for example, circular or rectangular in shape, and has thickness in the thickness direction of the substrate 1; it is a cylindrical or prismatic object.

[0060] (Fifth Embodiment)

[0061] Figure 9A , Figure 9B This is an enlarged view of a portion of the light-emitting device according to the fifth embodiment of this disclosure. Figure 9A This is a cross-sectional view of a portion of the light-emitting element viewed from the side. Figure 9BThis is a top view of a portion of the substrate 1 as seen from above. Furthermore, the same reference numerals are used for portions corresponding to the embodiments described above, and repeated descriptions are omitted. The optical waveguide package 50 of this embodiment includes a cylindrical heat sink 35, at least a portion of which is located within the substrate 1 and whose end face protrudes from the bottom surface of the recess 8. The heat sink 35 uses a material with a higher thermal conductivity than the first portion 31, such as an Al alloy or a Cu alloy. By embedding a heat sink 35 with a higher thermal conductivity than the substrate 1 directly below the light-emitting element 10 in the substrate 1, heat emitted from the light-emitting element 10 can be effectively dissipated. Furthermore, since a second portion 32, serving as a high-density bonding layer, is distributed on the side of the heat sink 35, the bonding strength between the electrode 15 mounted on the light-emitting element 10 and the substrate 1 can be increased. Additionally, the heat sink 35 can also be connected to at least a portion of the second portion 32, in which case heat dissipation and bonding strength are further improved. In addition, thermal conductivity can be measured and evaluated according to relevant specifications using methods such as hot plate method, probe method, heat flow method, and laser flash method.

[0062] (Sixth Embodiment)

[0063] Figure 10A , Figure 10B This is an enlarged view of a portion of the light-emitting device according to the sixth embodiment of this disclosure. Figure 10A This is a cross-sectional view of a portion of the light-emitting element viewed from the side. Figure 10B This is a top view of a portion of the substrate 1 as seen from above. Furthermore, the same reference numerals are used for portions corresponding to the embodiments described above, and repeated descriptions are omitted. The substrate 1 has a lower surface 16 located on the opposite side of the upper surface 2. The heat sink 35 has an embedded portion 35a and a plate-shaped portion 35b. The embedded portion 35a protrudes from the bottom surface of the recess 8 and extends from the bottom surface of the recess 8 to the lower surface 16. The plate-shaped portion 35b is connected to the embedded portion 35a and is located on the lower surface 16. Thus, by also providing the plate-shaped portion 35b as a bonding layer on the lower surface 16 of the substrate 1, and bonding it to the electrode 15 via the embedded portion 35, the bonding strength between the electrode 15 and the substrate 1 as a whole can be increased.

[0064] (Seventh Embodiment)

[0065] Figure 11A , Figure 11B This is an enlarged view of a portion of the light-emitting device according to the seventh embodiment of this disclosure. Figure 11A This is a cross-sectional view of a portion of the light-emitting element viewed from the side. Figure 11BThis is a top view of a portion of the substrate 1 as seen from above. Furthermore, the same reference numerals are used for portions corresponding to the embodiments described above, and repeated descriptions are omitted. In this embodiment, the plate-like portion 35b of the lower surface 16 of the substrate 1 of the optical waveguide package 50 is divided by a gap 36. This mitigates thermal stress and reduces breakage and light propagation loss caused by deformation of the substrate 1. Furthermore, when the substrate 1 is an insulator and the heat sink 35 contains a metallic material, power for driving the light-emitting element 10 can be provided from the lower surface 16.

[0066] (Eighth Embodiment)

[0067] Figure 12A , Figure 12B This is an enlarged view of a portion of the light-emitting device according to the eighth embodiment of this disclosure. Figure 12A This is a cross-sectional view of a portion of the light-emitting element viewed from the side. Figure 12B This is a top view of a portion of the substrate 1 as seen from above. Furthermore, the same reference numerals are used for portions corresponding to the embodiments described above, and repeated descriptions are omitted. The substrate 1 has a side surface 17 connected to the upper surface 2, and the cladding 3 further includes a covered portion 37 located on the side surface 17. This covered portion 37 allows the cladding 3 of the optical waveguide layer 5 to be extended to the side surface 17 of the substrate 1, thereby improving the adhesion strength of the optical waveguide layer 5 to the substrate 1.

[0068] (9th embodiment)

[0069] Figure 13A , Figure 13B This is an enlarged view of a portion of the light-emitting device according to the ninth embodiment of this disclosure. Figure 13A This is a cross-sectional view of a portion of the light-emitting element viewed from the side. Figure 13B This is a top view of a portion of the substrate 1 as seen from above. Furthermore, the same reference numerals are used for portions corresponding to the embodiments described above, and repeated descriptions are omitted. The substrate 1 has: a lower surface 16 located on the opposite side of the upper surface 2, and a side surface 17 connecting the upper surface 2 and the lower surface 16. The cladding 3 includes a covering portion 38 located on the side surface 17 and the lower surface 16, and covers the side surface 17 and the lower surface 16. Through this covering portion 38, the cladding 3 of the optical waveguide layer 5 can be extended to the side surface 17 and the lower surface 16 of the substrate 1, thereby improving the adhesion strength of the optical waveguide layer 5 to the substrate 1.

[0070] In further embodiments of this disclosure, the light-emitting element 10 is not limited to a light-emitting diode (LED), but may also be an LD (Laser Diode), VCSEL (Vertical Cavity Surface Emitting Laser), etc.

[0071] As described above, the optical waveguide package of this disclosure includes a substrate and an optical waveguide layer, the substrate having a first portion and a second portion exposed at least on the upper surface of the substrate. Furthermore, the second portion has a higher adhesion strength to the cladding layer than the first portion has to the cladding layer. Additionally, the light-emitting device of this disclosure includes the optical waveguide package and a light-emitting element housed in the recess of the optical waveguide package.

[0072] According to the optical waveguide package and light-emitting device disclosed herein, since the substrate has a first part and a second part, the thermal stress generated by the heat of the light-emitting element can be mitigated by the first part, and a higher bonding strength can be obtained by the second part. As a result, thermal stress can be mitigated, thereby reducing the peeling of the substrate from the optical waveguide layer.

[0073] The embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the embodiments described above, and various changes and improvements can be made without departing from the spirit of this disclosure. Of course, all or part of the embodiments described above can be appropriately combined within a non-contradictory scope.

[0074] Symbol Explanation

[0075] 1 substrate

[0076] 2. Upper surface

[0077] 3. Cladding

[0078] 4 cores

[0079] 4a, 4b, 4c Incident end faces

[0080] 5. Optical waveguide layer

[0081] 6. Top surface

[0082] 7. Lower surface

[0083] 8 concavity

[0084] 11 Sealing cover

[0085] 11a Lower surface of sealing cover 11

[0086] 13 Inner wall surface

[0087] 15 electrodes

[0088] 16 Lower surface

[0089] 17. Side view

[0090] 10 Light-emitting elements

[0091] 20 Light-emitting devices

[0092] 31 Part 1

[0093] 32 Part 2

[0094] 33 Granular bodies

[0095] 33a protrusion

[0096] 34 columnar bodies

[0097] 35 Radiator

[0098] 35a Installation Section

[0099] 35b plate-shaped part

[0100] 36 gaps

[0101] 37, 38 covered part

[0102] 41a, 41b, 41c Segmentation Paths

[0103] 42 Exit end face

[0104] 43 Combined Wave Department

[0105] 44 Integration Path

[0106] 45 Condensing Lens

[0107] 50 Optical Waveguide Package

[0108] 55. Bonding layer.

Claims

1. An optical waveguide package, comprising: A substrate having a first surface serving as a mirror, the substrate being made of a dielectric; and The optical waveguide layer has a cladding layer located on the first surface and a core located within the cladding layer. The substrate has a first portion and a second portion that are in contact with the cladding layer. The second part has a higher adhesion strength relative to the cladding than the first part has a higher adhesion strength relative to the cladding. The second part comprises a plurality of granular bodies dispersed within the first part, the granular bodies having protrusions. The surface of the substrate in the first surface that is in contact with the cladding is composed of the surface of the first part that is in contact with the cladding and the surface of the second part that is in contact with the cladding.

2. The optical waveguide package according to claim 1, wherein, The radius of curvature of the protrusion is 0.01 to 5 μm.

3. The optical waveguide package according to claim 1, wherein, The second part includes a columnar body extending in the thickness direction of the substrate.

4. The optical waveguide package according to claim 1 or 2, wherein, The optical waveguide package also includes: a heat sink, at least a portion of which is located within the substrate. The cladding further includes a recess, from which the heat sink protrudes from the bottom surface of the recess. The thermal conductivity of the radiator is higher than that of the first part.

5. The optical waveguide package according to claim 4, wherein, The substrate also has a second surface located on the opposite side of the first surface. The radiator has: an embedded portion that protrudes from the bottom surface of the recess and extends from the bottom surface of the recess to the second surface; and a plate-shaped portion located on the second surface.

6. The optical waveguide package according to claim 1 or 2, wherein, The substrate also has a third surface connected to the first surface. The cladding also includes a portion located on the third surface.

7. The optical waveguide package according to claim 1 or 2, wherein, The substrate further comprises: a second surface located on the opposite side of the first surface, and a third surface connecting the first surface and the second surface. The cladding also includes portions located on the third surface and the second surface.

8. The optical waveguide package according to claim 1, wherein, The substrate is formed by stacking multiple dielectric layers. The first part and the second part are each part of the dielectric layer.

9. The optical waveguide package according to claim 1, wherein, The first part is composed of aluminum nitride, boron nitride, zirconium carbide, diamond, and fluorine resin. The second part is composed of aluminum oxide, zirconium oxide, magnesium oxide, titanium dioxide, barium titanate, quartz glass, silicon dioxide, and silicon-based resin.

10. A light-emitting device, comprising: The optical waveguide package according to any one of claims 1 to 9; and The light-emitting element is connected to the optical waveguide package.

11. The light-emitting device according to claim 10, wherein, The cladding has a recess. The light-emitting element comprises three light-emitting elements that emit red light, green light, and blue light respectively. The three light-emitting elements are housed in the recess.

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