Optical waveguide package

Abstract

This optical waveguide package is provided with: a substrate (9) that has a first surface (8); a cladding (12) that is located on the first surface, has a second surface (10) facing the first surface and a third surface (11) located on the reverse side from the second surface, and has an element mounting region (3) opening on the third surface; a core (5) that is located within the cladding and has an incidence surface (13) fronting on the element mounting region and an emission surface (15) exposed from an end surface of the cladding; and a sidewall (16a) that surrounds the element mounting region on the substrate. The sidewall is provided with a sidewall comprising a plurality of materials having elastic moduli different from each other.

Description

Technical Field

[0001] The present disclosure relates to an optical waveguide package.

Prior Art Documents

Patent Documents

[0002]

Patent Document 1

Patent Document 2

Summary of the Invention

[0003] The optical waveguide package according to the present disclosure includes a substrate having a first surface, a clad located on the first surface, the clad having a second surface facing the first surface and a third surface located on the opposite side of the second surface, the clad having an element mounting region opening to the third surface, a core located within the clad and having an incident surface facing the element mounting region and an exit surface exposed from an end surface of the clad, and a side wall on the substrate at least partially surrounding the element mounting region, and the side wall is made of a plurality of materials having different elastic coefficients from each other.

Brief Description of the Drawings

[0004] The object, features, and advantages of the present disclosure will become clearer from the following detailed description and the drawings. [Figure 1] It is an exploded perspective view showing a light-emitting device including an optical waveguide package according to an embodiment of the present disclosure. [Figure 2] It is a plan view of the light-emitting device shown in FIG. 1. [Figure 3A] It is a cross-sectional view taken along the cutting plane line IIIA-IIIA of FIG. 2. [[ID=D46]] [Figure 3B] It is a cross-sectional view taken along the cutting plane line IIIB-IIIB of FIG. 2. [Figure 4] It is a partial perspective view showing an optical waveguide layer of the optical waveguide package shown in FIG. 1. [Figure 5]This is a plan view showing a light-emitting device of another embodiment of the present disclosure. [Figure 6] This is a plan view showing a light-emitting device of yet another embodiment of the present disclosure. [Figure 7] This is a plan view showing a light-emitting device of yet another embodiment of the present disclosure. [Figure 8] This is a plan view showing a light-emitting device of yet another embodiment of the present disclosure. [Figure 9] This is a cross-sectional view taken from the cross-section line IX-IX in Figure 8. [Figure 10] This is a plan view showing a light-emitting device of yet another embodiment of the present disclosure. [Modes for carrying out the invention]

[0005] A conventional optical waveguide package is described, for example, in Patent Document 1. Patent Document 1 discloses a configuration in which an optical waveguide is formed on a substrate, a groove is provided in a direction transverse to the optical waveguide, a light-shielding film is provided on the inner wall of the groove, and radiation modes generated within the optical waveguide element are prevented from leaking into the optical fiber facing the cladding mode light-emitting element.

[0006] Other conventional optical waveguide packages are described, for example, in Patent Document 2. Patent Document 2 discloses a configuration in which one end of the core and the gap in which the optical element is located are sealed hermetically by joining a cap to obtain gas barrier properties.

[0007] In the conventional technologies described in Patent Documents 1 and 2 above, a cover is bonded to the element mounting area. As a result, the mounting area deforms due to the stress during cover bonding, reducing the optical coupling efficiency between the light-emitting element and the waveguide. Therefore, there has been a need for an optical waveguide package that can reduce the decrease in optical coupling efficiency between the light-emitting element and the waveguide.

[0008] Figure 1 is an exploded perspective view showing a light-emitting device equipped with an optical waveguide package according to one embodiment of the present disclosure. Figure 2 is a plan view of the light-emitting device shown in Figure 1, Figure 3A is a cross-sectional view taken from the line IIIA-IIIA in Figure 2, and Figure 3B is a cross-sectional view taken from the line IIIB-IIIB in Figure 2. In the following embodiments, the materials constituting the side walls are described as having different elastic moduli and refractive indices.

[0009] The optical waveguide package 2 of this embodiment comprises a substrate 9 having a first surface 8, a cladding 12 located on the first surface 8 having a second surface 10 facing the first surface 8 and a third surface 11 located on the opposite side of the second surface 10, and having an element mounting region 3 opening to the third surface 11, a core 5 located within the cladding 12 and having an incident surface 13 facing the element mounting region 3 and an exit surface 15 exposed from the end surface 14 of the cladding 12, and side walls 16a on the substrate 9 that at least partially surround the element mounting region 3 and are made of a plurality of materials M1, M2 with different elastic moduli. The core 5 and the cladding 12 constitute an optical waveguide layer 19. In plan view, the substrate 9 is a rectangular plate-like body.

[0010] The light-emitting device 1 includes the aforementioned optical waveguide package 2, a light-emitting element 4 located within the element mounting area 3, a lens 6 located on the optical path of light emitted from the core 5, and a box-shaped cover 7, for example, with one side open, that covers the element mounting area 3. The cover 7 is not limited to a box shape, but may be plate-shaped, for example, and different shapes can be used as appropriate.

[0011] Figure 4 is a partial perspective view showing the optical waveguide layer of the optical waveguide package shown in Figure 1. The optical waveguide layer 19 may be made of glass such as quartz, resin, etc. The materials constituting the optical waveguide layer 19 may all be glass or resin, and one of the core 5 and cladding 12 may be glass and the other is resin. The refractive indices of the core 5 and cladding 12 are different, with the core 5 having a higher refractive index than the cladding 12. This difference in refractive index is used to cause total internal reflection of light at the interface between the core 5 and cladding 12. In other words, by creating an optical waveguide with a material with a high refractive index and surrounding it with a material with a low refractive index, light can be confined within the core 5 with a high refractive index.

[0012] The light-emitting device 1 is located within the element mounting area 3 and further comprises a first electrode 20 on which the light-emitting element 4 is mounted, and a second electrode 21 connected to the first electrode 20 and extending outward from the element mounting area 3. The lens 6 is located in the optical path of the light emitted from the core 5 and may parallelize or focus the light emitted from the core 5. The lens 6 may be, for example, a plano-convex lens with a planar incident surface and a convex exit surface.

[0013] The substrate 9 may be an organic wiring substrate in which the dielectric layer is made of an organic material, for example. Examples of organic wiring substrates include printed circuit boards, build-up wiring substrates, and flexible wiring substrates. Examples of organic materials used in organic wiring substrates include epoxy resins, polyimide resins, polyester resins, acrylic resins, phenolic resins, and fluororesins.

[0014] The substrate 9 may be a ceramic wiring substrate in which the dielectric layer is made of a ceramic material. Examples of ceramic materials used in ceramic wiring substrates include aluminum oxide sintered bodies, mullite sintered bodies, silicon carbide sintered bodies, aluminum nitride sintered bodies, and glass ceramic sintered bodies. The material of the substrate 9 may also be silicon, silicon dioxide, or silicon oxynitride (SiON).

[0015] The light-emitting element 4 includes a light-emitting element 4R that emits red light R, a light-emitting element 4G that emits green light G, and a light-emitting element 4B that emits blue light B. These light-emitting elements 4R, 4G, 4B may be, for example, light-emitting diodes (LEDs) or laser diodes (LDs). Each of the light-emitting elements 4R, 4G, 4B is arranged so that the light-emitting end of each color of light faces the incident surfaces 13R, 13G, 13B that are exposed facing the element mounting region 3 of the core 5. The core 5 may have a plurality of divided paths 41R, 41G, 41B having the incident surfaces 13R, 13G, 13B, a multiplexing section 17 where the plurality of divided paths 41R, 41G, 41B converge, and an integrated path 18 extending between the multiplexing section 17 and the exit surface 15. Each of the light-emitting elements 4R, 4G, 4B is positioned within the element mounting region 3 so that each optical axis of each of the light-emitting elements 4R, 4G, 4B coincides with the center of the incident end surfaces 4a, 4b, 4c of the divided optical path 41a, 41b, 41c of the optical axis.

[0016] The element mounting region 3 may be a recess or through-hole that opens to the third surface 11 of the cladding 12. In this embodiment, the element mounting region 3 is a through-hole that penetrates from the third surface 11 to the second surface 10 of the cladding 12. In a plan view, on the third surface 11 of the cladding 12, the bonding material 22 is located annularly so as to surround the opening of the element mounting region 3, and the lid body 7 is bonded to the third surface 11 of the cladding 12 by the bonding material 22. The inside of the element mounting region 3 is hermetically sealed by the lid body 7, and the light-emitting element 4 is protected.

[0017] The lid body 7 is made of, for example, a glass material such as quartz, borosilicate, or sapphire. The material of the bonding material may be any material that can bond the cladding 12 and the lid body 7 and can perform airtight sealing. For example, Au-Sn-based, Sn-Ag-Cu-based solder, metal-based nanoparticle paste such as Ag or Cu, or glass paste can be used.

[0018] The core 5 of this embodiment is made of silicon oxynitride (SiON), also referred to as silicon oxynitride, and the cladding 12 may be made of silicon dioxide (SiO2).

[0019] Multiple materials M1, M2, ..., M with different elastic moduli m-1 M m (where m is a positive integer) includes materials having the same refractive index difference Δn2 (=Δn1) as the refractive index difference Δn1 (=n11-n12) between core 5 (refractive index n11) and cladding 12 (refractive index n12). Multiple materials M1, M2, ..., M with different elastic moduli E from each other. m-1 M m This includes a first refractive index material M1 having a first refractive index n1 and a second refractive index material M2 having a second refractive index n2 that is lower than the first refractive index n1.

[0020] If the elastic modulus of core 5 is greater than that of cladding 12, the shape-retaining force of core 5 becomes dominant over the shape-restoring force of cladding 12, which is deformed by the pressing force applied to the remaining components excluding lid 7 due to the joining of lid 7, etc. Therefore, deformation of core 5 from the design shape is reduced, and the predetermined shape can be reliably achieved. Also, if the elastic modulus of core 5 is smaller than that of cladding 12, the deformation of cladding 12 due to the action of external forces is small, and as a result, the deformation transmitted from cladding 12 to core 5 is also small. By reducing the deformation of core 5, the decrease in optical transmission efficiency can be reduced. In this way, by constructing the side wall 16a with multiple materials M1, M2 with different elastic moduli, resistance to stress due to thermal deformation, for example, can be improved.

[0021] By using multiple materials with different elastic moduli, and materials having the same refractive index difference Δn2 as the refractive index difference Δn1 between the core 5 and the cladding 12, unwanted light such as reflected light within the element mounting region 3 can be emitted from the element mounting region 3 to the outside, preventing unwanted light from entering the core 5.

[0022] The first refractive index material M1 is located in a direction perpendicular to the first surface 8 and within the same height range as the incident surface 13 of the core 5. That is, the first refractive index material M1 is located at the center of the rear side wall 16a of the element mounting region 3. This allows unwanted light emitted from the light-emitting element 4 in the opposite direction to the incident surface of the core 5 to be emitted from the element mounting region 3 to the outside through the first refractive index material M1, thereby preventing unwanted light from being reflected by the inner surface of the side wall 16a and entering the core 5 from the incident surface 13. In this case, in order to emit such unwanted light from the element mounting region 3 to the outside, the first refractive index material M1 may be positioned so as to extend from the inner surface to the outer surface of the side wall 16a.

[0023] Since the side wall 16a is made up of multiple materials with different elastic moduli, even when a pressing force is applied from the lid 7 to the side wall 16a when the lid 7 is joined to the side wall 16a, that pressing force is distributed throughout the entire side wall 16a by traveling through the material with the higher elastic modulus, and the pressing force from the distributed material with the higher elastic modulus is absorbed by the material with the lower elastic modulus, thereby reducing deformation of the part that defines the element mounting area 3. This reduces deformation of the substrate 9, reduces the displacement of each light-emitting element 4R, 4G, 4B relative to the incident surfaces 13R, 13G, 13B, reduces the decrease in the amount of light incident from each light-emitting element 4R, 4G, 4B to each incident surface 13R, 13G, 13B, and reduces the decrease in light propagation efficiency.

[0024] Furthermore, the side wall 16a can be easily manufactured by forming at least one of the materials with different elastic moduli that make up the side wall 16a from the same material as the core 5 and cladding 12.

[0025] The aforementioned side wall 16a partially surrounds the element mounting area 3 and has a C-shape configuration at least in plan view. This allows the side wall 16a to be formed while avoiding the areas where the division paths 41R, 41G, and 41B of the core 5 are located. As a result, both circumferential ends of the side wall 16a are located on the end face 14 side of the incident surface 13 of the core 5. This prevents unwanted light that has passed through the first refractive index material M1 of the side wall 16a from entering the core 5 from the incident surface 13. Furthermore, the formation of the side wall 16a requires less influence from pressurization of the division paths 41R, 41G, and 41B, making the formation of the side wall 16a easier. Additionally, since the first refractive index material M1 is separated from the core 5, unwanted light that has passed through the first refractive index material M1 is less likely to enter the core 5 not only from the incident surface 13 but also from the sides.

[0026] Figure 5 is a plan view showing a light-emitting device of another embodiment of the present disclosure. The same reference numerals are used for parts corresponding to the previously described embodiments. In this embodiment, the optical waveguide package 2b has a side wall 16b that is formed in a closed loop shape in plan view, and the side wall 16b is provided around the entire circumference of the element mounting area 3. The material of the side wall 16b is the same as that of the side wall 16a described above. With this configuration, the side wall 16b is also interposed between each of the division paths 41R, 41G, and 41B of the core 5, which can mitigate the effects on each of the division paths 41R, 41G, and 41B, such as the pressing force when the cover 7 is joined.

[0027] Figure 6 is a plan view showing a light-emitting device of yet another embodiment of the present disclosure. The same reference numerals are used for parts corresponding to the previously described embodiments. In this embodiment, the optical waveguide package 2c is formed in a substantially closed loop shape in plan view, and multiple spacings ΔL are formed in the direction in which the side wall 16c extends, in the regions on both sides of the short side parallel to the direction in which each light-emitting element 4R, 4G, 4B is aligned, and in one region on the side facing the incident surfaces 13R, 13G, 13B in the long side. With this configuration, even if the side wall 16c expands due to heat from the light-emitting elements 4R, 4G, 4B, the strain due to thermal expansion can be absorbed by each spacing ΔL, thereby reducing deformation of the substrate 9 due to thermal expansion and reducing the decrease in optical coupling efficiency to the core 5.

[0028] Figure 7 is a plan view showing a light-emitting device of yet another embodiment of the present disclosure. The same reference numerals are used for parts corresponding to the previously described embodiments. The optical waveguide package 2d of this embodiment has a side wall 16c that is generally formed in a closed loop shape in plan view. The side wall 16c has a plurality of gaps 30 formed parallel to the long side direction in both regions of the short side direction parallel to the direction in which each light-emitting element 4R, 4G, 4B is arranged, and in one region of the long side direction facing the incident surfaces 13R, 13G, 13B. With this configuration, even if the side wall 16c expands due to heat from the light-emitting elements 4R, 4G, 4B, the distortion due to thermal expansion can be absorbed by each gap 30. This reduces deformation of the substrate 9 due to thermal expansion and reduces the decrease in optical coupling efficiency to the core 5.

[0029] Figure 8 is a plan view showing a light-emitting device of yet another embodiment of the present disclosure, and Figure 9 is a cross-sectional view taken from the line IX-IX of the cross section in Figure 8. The same reference numerals are used for parts corresponding to the previously described embodiments. The optical waveguide package 2e of this embodiment has a side wall 16e formed in a closed loop shape in plan view. The side wall 16e is positioned on the third surface 11 of the cladding 12 so as to surround the opening of the element mounting area 3. The thickness T of this side wall 16e is set to, for example, 0.1 μm or more and 10 μm or less. The side wall 16e may be joined to the third surface 11 by, for example, a bonding material. As the bonding material, for example, Au-Sn, Sn-Ag-Cu solder, a metal nanoparticle paste such as Ag or Cu, or a glass paste can be used. With such a configuration, it is possible to provide an optical waveguide package with excellent optical coupling efficiency and a light-emitting device using the same without significantly changing the configuration of existing optical waveguide packages.

[0030] Figure 10 is a plan view showing a light-emitting device of yet another embodiment of the present disclosure. The same reference numerals are used for parts corresponding to the previously described embodiments, and redundant descriptions are omitted. In this embodiment, the core 5 may consist of three independent cores 5R, 5G, and 5B. Similar to the embodiments described above, the incident surfaces 13R, 13G, and 13B of the three cores 5R, 5G, and 5B are positioned apart from each other, aligned with the position of each light-emitting element 4R, 4G, and 4B, such that the centers of the three incident surfaces 13R, 13G, and 13B coincide with the optical axes of each light-emitting element 4R, 4G, and 4B. The exit surfaces 15R, 15G, and 15B of the three cores 5R, 5G, and 5B are located close together, and the light emitted from the exit surfaces 15R, 15G, and 15B of each core 5R, 5G, and 5B may be emitted parallel to each other by, for example, a single lens 6. Between the incident surfaces 13R, 13G, 13B and the exit surfaces 15R, 15G, 15B, the three cores 5R, 5G, 5B may be brought together in close proximity and extend parallel to the exit surfaces 15R, 15G, 15B. In this case, images and the like from the light emitted from the three exit surfaces 15R, 15G, 15B may be combined, for example, by an external device.

[0031] In other embodiments, the light-emitting element 4 is not limited to a light-emitting diode, but may be, for example, an LD (Laser Diode), a VCSEL (Vertical Cavity Surface Emitting Laser), etc. That's fine.

[0032] In the embodiments described above, the case where two types of materials, a first refractive index material M1 and a second refractive index material M2, with different elastic moduli, are used as the materials constituting the side walls 16a to 16e was described. However, in other embodiments of this disclosure, three or more types of materials M1, M2, ..., Mm with different elastic moduli are used. -1 The side walls may be constructed using Mm (where m is a positive integer).

[0033] The optical waveguide package described herein provides an optical waveguide package in which the decrease in optical coupling efficiency between the light-emitting element and the waveguide is reduced.

[0034] This disclosure can be implemented in the following configurations (1) to (6).

[0035] (1) A substrate having a first surface, A cladding located on the first surface, having a second surface facing the first surface and a third surface located on the opposite side of the second surface, and having an element mounting region opening to the third surface, A core located within the cladding, having an incident surface facing the element mounting region and an exit surface exposed from the end face of the cladding, The substrate comprises a side wall that surrounds the element mounting area, The aforementioned sidewall is made of multiple materials with different elastic moduli, forming an optical waveguide package.

[0036] (2) The optical waveguide package according to (1) above, wherein at least one of the plurality of materials has a C-shaped portion in plan view.

[0037] (3) The plurality of materials having different elastic moduli include a material having the same refractive index difference as the refractive index difference between the core and the cladding. The plurality of materials with different elastic moduli include a first refractive index material having a first refractive index and a second refractive index material having a second refractive index lower than the first refractive index. The optical waveguide package according to (1) or (2) above, wherein the first refractive index material is located in a direction perpendicular to the first surface within the same height range as the incident surface of the core.

[0038] (4) The optical waveguide package described in (3) above, wherein the first refractive index material is located at a distance from the core.

[0039] (5) The side wall comprises a first material of the same material as the core and a second material of the same material as the cladding, disposed so as to sandwich the first material. The optical waveguide package according to any one of (1) to (4) above, wherein the first material has a higher elastic modulus than the second material.

[0040] (6) The side wall comprises a first material of the same material as the core and a second material of the same material as the cladding, disposed so as to sandwich the first material. The optical waveguide package according to any one of (1) to (4) above, wherein the first material has a lower elastic modulus than the second material.

[0041] Although embodiments of this disclosure have been described in detail above, this disclosure is not limited to the embodiments described above, and various modifications and improvements are possible without departing from the gist of this disclosure. It goes without saying that all or part of each of the above embodiments can be combined as appropriate and in a non-contradictory manner. [Explanation of symbols]

[0042] 1. Light-emitting device 2 Optical waveguide packages 3-element mounting area 4; 4R, 4G, 4B Electrolyte 5; 5R, 5G, 5B core 6 lenses 8 Front page 9 circuit boards 10 Side 2 11 Page 3 12 clad 13;13R,13G,13B Incidence surface 14 End face 15. Ejection surface 16a~16e side wall 17 Wave section 18 Integrated Road 19 Optical waveguide layer 20 1st electrode 21 2nd electrode 41R,41G,41B Divided road M1 First refractive index material M2 Second refractive index material

Claims

1. A substrate having a first surface, A cladding located on the first surface, having a second surface facing the first surface and a third surface located on the opposite side of the second surface, having an element mounting region opening to the third surface and a side surface surrounding the element mounting region, A core having an incident surface located within the cladding, exposed on the side surface and facing the element mounting area, and an exit surface exposed from the end face of the cladding, A side wall member is located at least partially within the cladding and surrounds the element mounting area at least partially, with a gap between it and the core. A cover located on the cladding and covering the element mounting area comprises, The cover overlaps with the side wall member and the core in a planar perspective view. An optical waveguide package wherein the elastic modulus of the side wall member is different from that of the cladding.

2. The optical waveguide package according to claim 1, wherein the side wall member includes a C-shaped portion in a plan view.

3. The optical waveguide package according to claim 1 or 2, wherein the side wall member is positioned in a closed loop around the element mounting area in a plan view.

4. The optical waveguide package according to claim 3, wherein the side wall members are intermittently located around the element mounting area.

5. The side wall member comprises a first material of the same material as the core, The optical waveguide package according to claim 1 or 2, wherein the first material has a higher elastic modulus than the material of the cladding.

6. The side wall member comprises a first material of the same material as the core, The optical waveguide package according to claim 1 or 2, wherein the first material has a lower elastic modulus than the material of the cladding.

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