Waveguide terminator and optical module

Abstract

The present application relates to the technical field of optical communications, and in particular to a waveguide terminator and an optical module. The waveguide terminator comprises an optical absorber and a transmission waveguide that are stacked and spaced apart, wherein the transmission waveguide comprises a first waveguide section and a second waveguide section, and the second waveguide section is located within a projection area of the optical absorber and is used for diverging an optical field. One end of the first waveguide section is connected to the second waveguide section, and the other end of the first waveguide section extends out of the projection area of the optical absorber and is used for transmitting incident light, that is inputted from the outside, to the second waveguide section. The included angle between the tangent line of the first waveguide section at the boundary of the projection area of the optical absorber and the boundary is less than 90°, so that a small amount of light reflected at the boundary where the refractive index suddenly changes can enter a cladding and be dissipated, thereby minimizing additional return loss as much as possible, and further reducing the return loss of an optical chip.

Description

Waveguide terminator and optical module

[0001] This application claims priority to Chinese Patent Application No. 202520454501.0, filed on March 14, 2025, entitled "Waveguide Terminal and Optical Module", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optical communication technology, and in particular to a waveguide terminator and an optical module. Background Technology

[0003] A waveguide terminator is an optical device used to absorb or dissipate optical signals in an optical waveguide in order to effectively terminate the transmission of the waveguide.

[0004] Return loss is an important metric in the field of communications, used to evaluate the performance of lines and equipment. Excessive return loss can lead to signal attenuation, interference, and other problems, affecting communication quality. Therefore, controlling return loss plays a crucial role in ensuring stable and reliable signal transmission.

[0005] Optical chip links contain some branches that do not require detection. At the ends of these branches, optical waveguide terminators are typically connected to absorb or dissipate the residual light output from these branches, thereby reducing the return loss of the optical chip. However, optical signals usually enter the waveguide terminator through the waveguide in a perpendicular manner. This incident manner causes significant reflection at interfaces with large changes in refractive index. This reflected light will return along the original waveguide path, generating additional return loss. Utility Model Content

[0006] This application provides a waveguide terminator and an optical module to solve the technical problem that existing waveguide terminators generate additional return loss.

[0007] This application provides a waveguide terminator, comprising:

[0008] Cladding;

[0009] The light absorber is located within the cladding.

[0010] A transmission waveguide is disposed within the cladding and is spaced from the optical absorber in a direction perpendicular to the cladding surface.

[0011] The transmission waveguide includes a first waveguide segment and a second waveguide segment. The second waveguide segment is located within the projection area of ​​the optical absorber and is used to diffuse the light field. One end of the first waveguide segment is connected to the second waveguide segment, and the other end extends beyond the projection area of ​​the optical absorber to transmit externally input incident light to the second waveguide segment.

[0012] The incident light is transmitted from the first waveguide section to the second waveguide section and is diverged by the second waveguide section. The light absorber is used to absorb the diverged light. The incident light transmitted in the first waveguide section will be partially reflected at the boundary of the projection area to form reflected light.

[0013] The angle between the tangent of the first waveguide segment at the boundary of the projection area of ​​the optical absorber and the boundary is less than 90°, so that the reflected light is reflected out of the transmission waveguide to the cladding.

[0014] The projection area of ​​the optical absorber is the projection of the optical absorber onto the waveguide layer where the transmission waveguide is located.

[0015] In one embodiment of this application, the included angle is α, which satisfies: 20°≤α≤40°.

[0016] In one embodiment of this application, the first waveguide segment is a multimode waveguide.

[0017] In one embodiment of this application, the width of the multimode waveguide is W1, which satisfies: 1.5μm ≤ W1 ≤ 3μm.

[0018] In one embodiment of this application, the two ends of the second waveguide segment are a first end and a second end, respectively, and the first end is connected to the first waveguide segment; the width of the second waveguide segment at each position in its extension direction gradually decreases along the direction toward the second end, and the width of the second end is 200nm to 400nm.

[0019] In one embodiment of this application, the second waveguide segment is wound inward from the first end.

[0020] In one embodiment of this application, the second waveguide segment is an Archimedes spiral waveguide.

[0021] In one embodiment of this application, the second waveguide segment is a multimode waveguide structure with abrupt changes or a fan-shaped focusing grating waveguide structure.

[0022] In one embodiment of this application, the spacing is greater than or equal to 80 nm and less than or equal to 300 nm.

[0023] In one embodiment of this application, the transmission waveguide is one of silicon nitride waveguide, lithium niobate waveguide, or silicon oxynitride waveguide.

[0024] In one embodiment of this application, the first waveguide segment is a curved waveguide, which includes one of Euler curved waveguide, Bessel curved waveguide, cosine curved waveguide, and sine curved waveguide.

[0025] In one embodiment of this application, the absorber includes a first semiconductor layer and a second semiconductor layer, the second semiconductor layer being an absorption layer, and the second semiconductor layer being stacked on the side of the first semiconductor layer facing away from the transmission waveguide.

[0026] In one embodiment of this application, the material of the second semiconductor layer includes germanium, doped silicon, indium phosphide, and indium gallium arsenide.

[0027] In one embodiment of this application, the material of the first semiconductor layer includes intrinsic silicon and doped silicon.

[0028] In one embodiment of this application, the thickness of the second semiconductor layer is greater than or equal to 300 nm.

[0029] In one embodiment of this application, the absorber includes a doped silicon layer for absorbing the emitted light.

[0030] Accordingly, this application also provides an optical module, including the waveguide terminator described in the above embodiments.

[0031] One of the above technical solutions has the following advantages or beneficial effects:

[0032] In this application, the angle between the tangent of the first waveguide segment at the boundary of the projection area of ​​the optical absorber and the boundary is less than 90°. By setting the first waveguide segment to cross the boundary of the abrupt change in refractive index of the waveguide terminator at an angle, the reflected light formed after a small amount of reflection at the boundary of the abrupt change in refractive index when the light enters the waveguide terminator can enter the cladding and be dissipated, instead of returning along the original path. This minimizes the generation of additional return loss and further reduces the return loss of the optical chip, thereby ensuring the stability and reliability of signal transmission. Attached Figure Description

[0033] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0034] Figure 1 is a cross-sectional schematic diagram of a waveguide terminator provided in an embodiment of this application;

[0035] Figure 2 is a schematic diagram of the structure of a waveguide terminator provided in an embodiment of this application;

[0036] Figure 3 is a schematic diagram of optical field simulation of a waveguide terminator provided in an embodiment of this application;

[0037] Figure 4 is a schematic diagram of the structure of a waveguide terminator provided in another embodiment of this application;

[0038] Figure 5 is a schematic diagram of the structure of a waveguide terminator provided in another embodiment of this application;

[0039] Figure 6 is a cross-sectional schematic diagram of a waveguide terminator provided in another embodiment of this application. Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0041] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document, unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship.

[0042] A waveguide terminator is an optical device used to absorb or dissipate optical signals in an optical waveguide to effectively terminate waveguide transmission. There are two existing technical solutions for waveguide terminators: dissipative and absorptive. Dissipative waveguide terminators utilize the curvature mismatch between the straight and curved waveguides at the interface, as well as the scattering phenomenon caused by the curved waveguide structure, to dissipate the optical signal. Absorptive waveguide terminators use a specific coupling structure with strong absorptive properties to guide the optical signal into the material for absorption. Comparatively, dissipative waveguide terminators have a larger footprint and are more likely to affect other photonic devices in the vicinity, causing signal crosstalk. Absorptive waveguide terminators, on the other hand, suffer from abrupt changes in the effective refractive index of the waveguide. Since the optical signal typically enters the terminator perpendicularly through the waveguide, significant reflection occurs at the interface where the refractive index changes, resulting in additional return loss.

[0043] Therefore, this application provides a waveguide terminator that helps reduce additional return loss and ensures the stability and reliability of signal transmission.

[0044] Specifically, referring to Figures 1 to 3, Figure 1 is a cross-sectional schematic diagram of a waveguide terminator provided in an embodiment of this application, Figure 2 is a structural schematic diagram of a waveguide terminator provided in an embodiment of this application, and Figure 3 is a schematic diagram of an optical field simulation of a waveguide terminator provided in an embodiment of this application. The waveguide terminator is disposed on a substrate 10 and includes a cladding layer 20, a light absorber 30, and a transmission waveguide 40. The light absorber 30 and the transmission waveguide 40 are disposed within the cladding layer 20 and are spaced 70 apart from the light absorber 30 in a direction perpendicular to the surface of the cladding layer 20. In this embodiment, the spacing 70 is greater than or equal to 80 nm and less than or equal to 300 nm. Specifically, the cladding layer 20 is disposed on one side surface of the substrate 10. The substrate 10 can be made of silicon, sapphire, quartz, or other materials, and is not limited thereto; the cladding layer 20 can be made of silicon dioxide. The direction perpendicular to the surface of the cladding layer 20 can be understood as the stacking direction of the cladding layer 20 and the substrate 10.

[0045] The transmission waveguide 40 includes a first waveguide segment 410 and a second waveguide segment 420. The second waveguide segment 420 is located within the projection region 340 of the optical absorber 30 and is used to diverge the light field. One end of the first waveguide segment 410 is connected to the second waveguide segment 420, and the other end extends beyond the projection region of the optical absorber 30, used to transmit externally input incident light 51 to the second waveguide segment 420. The externally input incident light 51 can refer to light outside the waveguide terminator within the optical chip; for example, this light can be transmitted from other waveguides within the optical chip and coupled to the transmission waveguide 40 of the waveguide terminator. The incident light 51 is transmitted from the first waveguide segment 410 to the second waveguide segment 420 and is diverged by the second waveguide segment 420. The optical absorber 30 is used to absorb the diverged light.

[0046] The incident light 51 transmitted within the first waveguide segment 410 will be partially reflected at the boundary 341 of the projection region 340 to form reflected light 52. Here, the projection region 340 of the light absorber 30 is the projection of the light absorber 30 onto the waveguide layer 60 where the transmission waveguide 40 is located. The angle between the tangent P of the first waveguide segment 410 at the boundary 341 of the projection region 340 of the light absorber 30 and the boundary 341 is α, which is less than 90°, so that the reflected light 52 is reflected out of the transmission waveguide 40 to the cladding 20. Specifically, during the process of the externally input incident light 51 entering the waveguide terminator through the first waveguide segment 410, it will be partially reflected at the interface where the effective refractive index of the waveguide changes abruptly, which is the boundary 341 of the projection region 340 of the light absorber 30. In this embodiment, the angle α between the tangent P of the first waveguide segment 410 at the boundary 341 of the projection region 340 of the light absorber 30 and the boundary 341 is less than 90°. That is, by setting the first waveguide segment 410 to cross the boundary of the abrupt change in refractive index of the waveguide terminator in an inclined manner, the reflected light formed after being reflected in a small amount at the boundary of the abrupt change in refractive index when the light enters the waveguide terminator can enter the cladding 20 and be dissipated, instead of returning along the original path. This avoids generating additional return loss as much as possible, and can further reduce the return loss of the optical chip to ensure the stability and reliability of signal transmission.

[0047] In one embodiment, the angle α between the tangent P of the first waveguide segment 410 at the boundary 341 of the projection region 340 of the optical absorber 30 and the boundary 341 further satisfies: 20°≤α≤40°, that is, the size of the angle α is preferably in the range of 20° to 40°. It is understood that the angle α can be reasonably adjusted according to the material of the optical absorber 30 to achieve better return loss. When different materials are selected for the optical absorber 30, the specific value of the angle α will also be different.

[0048] In one embodiment, the first waveguide segment 410 is a multimode waveguide. The width of this multimode waveguide is W1, satisfying: 1.5μm≤W1≤3μm. It is understood that multimode waveguides made of different materials may have different widths. Compared to single-mode waveguides, the effective refractive index change at the interface of a multimode waveguide is smaller, which reduces light reflection at the interface and helps to further reduce return loss, ensuring the stability and reliability of signal transmission.

[0049] In some embodiments, the first waveguide segment 410 is a curved waveguide, which can be one of an Euler curved waveguide, a Bessel curved waveguide, a cosine curved waveguide, or a sine curved waveguide. In other embodiments, the first waveguide segment 410 can also be a straight waveguide, or a combination of a straight waveguide and a curved waveguide. For example, the contact portion between the first waveguide segment 410 and the boundary 341 of the projection region 340 is straight, and the angle α between the straight portion and the boundary 341 of the projection region 340 is an acute angle. The connection portion between the first waveguide segment 410 and the second waveguide segment 420 is curved to achieve a smooth transition between the first waveguide segment 410 and the second waveguide segment 420.

[0050] Further, referring to Figure 2, the two ends of the second waveguide segment 420 are a first end 421 and a second end 422, respectively. The first end 421 is connected to the first waveguide segment 410. The width of the second waveguide segment 420 at various positions along its extension direction gradually decreases towards the second end 422. In this embodiment, the width at the connection point between the second waveguide segment 420 and the first waveguide segment 410 is the same as the width of the first waveguide segment 410, and the width of the second end 422 of the second waveguide segment 420 is 200nm to 400nm. In other embodiments, the width of the first end 421 of the second waveguide segment 420 and the first waveguide segment 410 may be different, and the first waveguide segment 410 can be thermally connected to the second waveguide segment 420 through a mode converter. Thus, the gradually decreasing width of the second waveguide segment 420 can effectively disperse the light field, allowing the light absorber 30 to better absorb the light signal and minimize return loss.

[0051] In one embodiment, the second waveguide segment 420 is coiled inward from the first end 421. Specifically, the second waveguide segment 420 can be an Archimedes spiral waveguide or the like. Of course, in other embodiments of this application, the second waveguide segment 420 can also be other divergent waveguide structures, such as the abrupt multimode waveguide structure shown in Figure 4, or the fan-shaped focusing grating waveguide structure shown in Figure 5, etc., and is not limited here.

[0052] In this embodiment, the transmission waveguide 40 is a silicon nitride waveguide. In other embodiments, the transmission waveguide 40 may also be made of other materials capable of achieving low-loss optical signal transmission, such as lithium niobate waveguides or silicon oxynitride waveguides, etc., and is not limited here.

[0053] In one embodiment, the absorber 30 includes a first semiconductor layer 310 and a second semiconductor layer 320, the second semiconductor layer 320 being an absorption layer, and stacked on the side of the first semiconductor layer 310 facing away from the transmission waveguide 40. For example, the second semiconductor layer 320 may be partially embedded in the side of the first semiconductor layer 310 facing away from the transmission waveguide 40, or the second semiconductor layer 320 may be stacked on the surface of the first semiconductor layer 310 facing away from the transmission waveguide 40, without being embedded in the first semiconductor layer 310.

[0054] In this embodiment, the first semiconductor layer 310 can be made of silicon, such as intrinsic silicon or doped silicon. The second semiconductor layer 320 is made of germanium and can be grown on the first semiconductor layer 310, for example, using an epitaxial growth process. In this embodiment, the orthographic projection of the first semiconductor layer 310 onto the cladding 20 surface is greater than or equal to the orthographic projection of the second semiconductor layer 320 onto the cladding 20 surface, and the orthographic projection of the first semiconductor layer 310 onto the cladding 20 surface covers the orthographic projection of the first semiconductor layer 310 onto the cladding 20 surface, thereby providing sufficient epitaxial growth space for the second semiconductor layer 320. Taking the second semiconductor layer 320 embedded on the side of the first semiconductor layer 310 facing away from the transmission waveguide 40 as an example, a groove can be formed on the side of the first semiconductor layer 310 facing away from the transmission waveguide 40, and then the second semiconductor layer 320 can be epitaxially grown inside and outside the groove. Alternatively, the second semiconductor layer 320 can be directly epitaxially grown on the surface of the first semiconductor layer 310 facing away from the transmission waveguide 40.

[0055] In this embodiment, the thickness of the second semiconductor layer 320 is greater than or equal to 300 nm. By reasonably setting the thickness of the second semiconductor layer 320, this embodiment facilitates more complete light absorption by the second semiconductor layer 320.

[0056] In this embodiment, the transmission waveguide 40 is made of silicon nitride and is integrated into the first semiconductor layer 310 on the side facing away from the second semiconductor layer 320 using a back-facing process. In the front-facing integration process of the waveguide terminator, since an electrode structure needs to be laid above the second semiconductor layer 320, the transmission waveguide 40 cannot overlap with the second semiconductor layer 320. Therefore, silicon nitride waveguide terminators using a front-facing integration process are generally dissipative. If a front-facing integrated waveguide terminator is to be made absorbing, the optical signal can only be guided into the silicon waveguide and then transmitted from the silicon waveguide to the germanium material region for absorption. The coupling structure from silicon nitride to the silicon waveguide introduces new return loss. In this application, the second semiconductor layer 320 is stacked on the side of the first semiconductor layer 310 facing away from the transmission waveguide 40. That is, the transmission waveguide 40 is fabricated on the side of the first semiconductor layer 310 facing away from the second semiconductor layer 320 using a back-to-back integration process. This avoids the problem of silicon nitride not overlapping with germanium material regions and does not affect the electrode structure on the side of the second semiconductor layer 320 facing away from the transmission waveguide 40, making metal wiring more convenient. With this arrangement, electricity and light can be distributed on different sides of the light absorber 30 without interference. Furthermore, light can be directly emitted from the second waveguide segment 420 of the transmission waveguide 40 and absorbed by the light absorber 30, eliminating the need for additional coupling structures to affect return loss during light transmission.

[0057] In other embodiments, the transmission waveguide 40 can also be made of lithium niobate, silicon, silicon oxynitride, or other materials. The light absorber 30 can also be made of other materials suitable for photodetectors used in communication bands, such as doped silicon, indium phosphide, indium gallium arsenide, or other materials with high nk coefficients; this is not limited here. Here, the nk coefficient is a parameter describing the speed of light propagation in a material, where n represents the refractive index and k represents the absorption coefficient. By selecting appropriate materials and adjusting their nk values, the characteristics of light propagation speed and absorption capacity can be controlled, thereby achieving the desired optical function.

[0058] Please also refer to Figure 6, which is a cross-sectional schematic diagram of a waveguide terminator provided in another embodiment of this application.

[0059] Unlike the embodiments described above, the structure of the light absorber 30 in this embodiment differs. In this embodiment, the light absorber 30 includes only a doped silicon layer 330, which is used to absorb diffused light. The light absorber 30 provided in this embodiment only requires doping to form the doped silicon layer 330 on the silicon layer to absorb light. The manufacturing process of the light absorber 30 in this embodiment is simpler, and the transmission waveguide 40 can be integrated on one side of the doped silicon layer 330 using either forward or back integration processes, resulting in a wider range of applications and more flexible structural design for the waveguide terminator.

[0060] Furthermore, one embodiment of this application also provides an optical module including the waveguide terminator of any of the above embodiments. The waveguide terminator has been described in detail in the above embodiments and will not be repeated here. Specifically, the optical module may include a photonic integrated chip, which integrates the above-mentioned waveguide terminator and other optical links. The optical links may include semiconductor optical devices and other waveguides, and the waveguide terminator may be connected to the branch end of the optical link.

[0061] In addition, this application also provides a fabrication process for a waveguide terminator, including the following steps:

[0062] S1: Provide a semiconductor-on-insulator wafer, such as a silicon-on-insulator (SOI) wafer, which includes a substrate, a buried oxide layer and a silicon layer. A germanium-silicon light absorber is fabricated on the front side of the wafer through processes such as etching and epitaxial growth, and an upper cladding layer and other front-side structures are fabricated.

[0063] S2: Flip the wafer with the light absorber 30 and bond it to a new substrate 10, which can serve as a support substrate for the wafer to ensure the stability of the wafer.

[0064] S3: Grind away the original substrate and buried oxide layer of the wafer, leaving a thinner buried oxide film as part of the cladding layer, and polish it.

[0065] S4: The transmission waveguide 40 in the above embodiment is prepared on the buried oxide layer film, and the angle between the tangent P of the transmission waveguide 40 at the boundary 341 of the projection area 340 of the light absorber 30 and the boundary 341 is an acute angle, so as to ensure that the optical signal enters the waveguide terminator at an angle.

[0066] S5: A lower cladding layer is covered on the side of the transmission waveguide 40 facing away from the light absorber 30. This lower cladding layer, together with the buried oxide film and the upper cladding layer, forms the cladding layer 20.

[0067] It is understood that in step S1, the light absorber 30 can be made of other materials that can be used in photodetectors for communication bands, such as silicon, indium phosphide, indium gallium arsenide, etc., and is not limited here. In step S4, the material of the transmission waveguide 40 can be a material that can achieve low-loss transmission of optical signals, such as silicon nitride, lithium niobate, silicon, silicon oxynitride, etc., and is not limited here.

[0068] In summary, the angle between the tangent of the first waveguide segment at the boundary of the projection area of ​​the optical absorber and the boundary is less than 90°. By setting the first waveguide segment to cross the boundary of the abrupt change in refractive index of the waveguide terminator at an angle, the reflected light formed after a small amount of reflection at the boundary of the abrupt change in refractive index when the light enters the waveguide terminator can enter the cladding and be dissipated, instead of returning along the original path. This minimizes the generation of additional return loss and further reduces the return loss of the optical chip, thereby ensuring the stability and reliability of signal transmission.

[0069] The above description is only a partial implementation of the embodiments of this application and is not intended to limit the application in any way. The protection scope of the embodiments of this application is not limited thereto. Any simple modifications, equivalent changes and alterations that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A waveguide terminator, comprising: The waveguide terminal device comprises: a cladding layer; a light absorber arranged in the cladding layer; a transmission waveguide arranged in the cladding layer and having a spacing with the light absorber in a direction perpendicular to a surface of the cladding layer; wherein the transmission waveguide comprises a first waveguide segment and a second waveguide segment, the second waveguide segment is located in a projection area of the light absorber and is used for diverging a light field; one end of the first waveguide segment is connected to the second waveguide segment, and the other end of the first waveguide segment extends out of the projection area of the light absorber and is used for transmitting an incident light inputted from outside to the second waveguide segment; the incident light is transmitted from the first waveguide segment to the second waveguide segment and is diverged by the second waveguide segment, and the light absorber is used for absorbing the diverged light; the incident light transmitted in the first waveguide segment will be partially reflected at a boundary of the projection area to form a reflected light; an included angle between a tangent of the first waveguide segment at the boundary of the projection area of the light absorber and the boundary is less than 90°, so that the reflected light is reflected out of the transmission waveguide to the cladding layer; the projection area of the light absorber is a projection of the light absorber on a waveguide layer where the transmission waveguide is located.

2. The waveguide terminator of claim 1, wherein, The included angle is α, and the included angle satisfies 20°≤α≤40°.

3. The waveguide terminator of claim 1, wherein, The first waveguide segment is a multimode waveguide.

4. The waveguide terminal device according to claim 3, wherein a width of the multimode waveguide is W1, and the width satisfies 1.5 μm ≤W1≤3 μm.

5. The waveguide terminator of claim 3, wherein, two ends of the second waveguide segment are a first end and a second end respectively, the first end is connected to the first waveguide segment; a width of the second waveguide segment at each position in an extension direction of the second waveguide segment gradually decreases along a direction towards the second end; a width of the second end is 200 nm to 400 nm.

6. The waveguide terminal device according to claim 5, wherein the second waveguide segment is arranged in a spiral inward from the first end.

7. The waveguide terminal device according to claim 6, wherein the second waveguide segment is an Archimedes spiral waveguide.

8. The waveguide terminal device according to claim 1, wherein the second waveguide segment is a sudden multimode waveguide structure or a fan-shaped focusing grating waveguide structure.

9. The waveguide terminal device according to claim 1, wherein the spacing is greater than or equal to 80 nm and less than or equal to 300 nm.

10. The waveguide terminator of claim 1, wherein, the transmission waveguide is one of a silicon nitride waveguide, a lithium niobate waveguide, and a silicon oxynitride waveguide.

11. The waveguide terminator of claim 1, wherein, the first waveguide segment is a curved waveguide, and the curved waveguide comprises one of an Euler curved waveguide, a Bessel curved waveguide, a cosine curved waveguide, and a sine curved waveguide.

12. The waveguide terminator of claim 1, wherein, the absorber comprises a first semiconductor layer and a second semiconductor layer, the second semiconductor layer is an absorbing layer, and the second semiconductor layer is stacked on a side of the first semiconductor layer away from the transmission waveguide.

13. The waveguide terminator of claim 12, wherein, a material of the second semiconductor layer comprises one of germanium, doped silicon, indium phosphide, and indium gallium arsenide.

14. The waveguide terminator of claim 12, wherein, a material of the first semiconductor layer comprises one of intrinsic silicon and doped silicon.

15. The waveguide terminator of claim 12, wherein, a thickness of the second semiconductor layer is greater than or equal to 300 nm.

16. The waveguide terminal device according to claim 1, wherein The absorber includes a doped silicon layer for absorbing the diverging light.

17. An optical module characterized by comprising: The waveguide terminator includes any one of claims 1-16.

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