Optical waveguide terminator, photonic integrated chip and optical module
By designing a spiral structure optical waveguide terminator, the optical coupling and absorption of the optical waveguide terminator are isolated from other surrounding waveguides, thus solving the problem of optical crosstalk between the optical waveguide terminator and nearby waveguides, and realizing the miniaturization of the optical waveguide terminator and the isolation of the optical field.
Patent Information
- Application Number
- CN202411091239.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-09
- Publication Date
- 2026-02-10
AI Technical Summary
Existing optical waveguide terminators are prone to causing optical crosstalk to other waveguides.
Design an optical waveguide terminator, including a transmission waveguide and an absorption waveguide. The transmission waveguide is wound at least one turn and coupled to the absorption waveguide. Light is coupled into the absorption waveguide through a spiral structure to prevent light leakage to the outer ring. The spiral structure of the transmission waveguide and absorption waveguide is used to isolate the optical waveguide terminator from other surrounding waveguides.
It effectively isolates the optical waveguide terminator from optical crosstalk to other nearby waveguides, avoids the influence of the absorbing waveguide on the optical field, and reduces the area occupied by the optical waveguide terminator.
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Figure CN121500480A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of optical communication technology, and in particular to an optical waveguide terminal, a photonic integrated chip, and an optical module. Background Technology
[0002] 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. Optical chip links contain some branches that do not require probes; at the ends of these branches, optical waveguide terminators are typically connected to reduce return loss.
[0003] Conventional optical waveguide terminators are dissipative, utilizing the curvature mismatch between straight and curved waveguides to increase propagation loss, causing most of the light to diverge. Ultimately, almost no light passes through the end of the terminator, thus reducing return loss. Ridge waveguide dissipative waveguide terminators can diverge the light field even better, but at the cost of requiring a larger footprint. Furthermore, in a compact optical chip layout, the light emitted by the waveguide terminator can cause additional crosstalk problems. Summary of the Invention
[0004] The purpose of this invention is to provide an optical waveguide terminator, a photonic integrated chip, and an optical communication device to solve the technical problem that existing optical waveguide terminators are prone to causing optical crosstalk to other waveguides.
[0005] To achieve the above objectives, the present invention provides an optical waveguide terminator, comprising a transmission waveguide and an absorption waveguide; wherein, the transmission waveguide includes a first transmission waveguide segment and a second transmission waveguide segment connected to each other, the first transmission waveguide segment having a port for receiving external incident light, the port being relatively far from the second transmission waveguide segment; the first transmission waveguide segment is wound inward at least one turn from the port, the second transmission waveguide segment being located within the coil of the first transmission waveguide segment, the second transmission waveguide segment being used for optical coupling with the absorption waveguide to couple the light transmitted within the transmission waveguide to the absorption waveguide; the orthographic projection of the absorption waveguide onto the plane of the transmission waveguide is located within the coil of the first transmission waveguide segment, the absorption waveguide being used to absorb the light it receives.
[0006] In some embodiments, the optical waveguide terminator includes a cladding and a first waveguide layer and a second waveguide layer stacked within the cladding, wherein the transmission waveguide is located in the first waveguide layer and the absorption waveguide is located in the second waveguide layer; the orthographic projection of the second transmission waveguide segment onto the second waveguide layer at least partially coincides with the absorption waveguide.
[0007] In some embodiments, the absorbing waveguide includes a first absorbing waveguide segment and a second absorbing waveguide segment connected to each other. The end of the first absorbing waveguide segment that is relatively far away from the second absorbing waveguide segment is the beginning of the absorbing waveguide, and the end of the second absorbing waveguide segment that is relatively far away from the first absorbing waveguide segment is the end of the absorbing waveguide. The projections of the first absorbing waveguide segment and the second transmission waveguide segment onto the second waveguide layer coincide. The waveguide width of the second transmission waveguide segment gradually decreases from its position near the beginning of the absorbing waveguide towards its end, while the waveguide width of the first absorbing waveguide segment gradually increases from its beginning towards its end near the second absorbing waveguide segment until it is the same size as the second absorbing waveguide segment, thereby achieving thermally insulating optical coupling between the second transmission waveguide segment and the first absorbing waveguide segment.
[0008] In some embodiments, the length of overlap between the projection of the second transmission waveguide segment and the first absorption waveguide segment ranges from 50 to 100 μm.
[0009] In some embodiments, the absorbing waveguide is wound inward from one end coupled to the second transmission waveguide; the cross-sectional dimensions of the second absorbing waveguide segment gradually decrease at the end away from the first absorbing waveguide segment.
[0010] In some embodiments, both the transmission waveguide and the absorption waveguide are helical structures, and the helical structure is composed of multiple curved waveguide segments connected in sequence. The multiple curved waveguide segments include one or more combinations of Euler curved waveguides, Bessel curved waveguides, sine curved waveguides, cosine curved waveguides, laterally offset curved waveguides, groove-etched curved waveguides, and center-widened curved waveguides.
[0011] In some embodiments, the absorbing waveguide includes a metal waveguide located on at least one side of the second transmission waveguide segment. The second transmission waveguide segment is connected to the metal waveguide through a plurality of metal vias, such that light transmitted in the second transmission waveguide segment is absorbed by the metal vias and transmitted to the metal waveguide.
[0012] In some embodiments, the absorbing waveguide includes a transition waveguide and a metal waveguide. The transition waveguide includes a coupled transmission section and a metal contact section connected together. The coupled transmission section is used to optically couple the second transmission waveguide section to receive and transmit light from the second transmission waveguide section. The metal contact section is a doped waveguide located on at least one side of the metal contact section and connected to the metal contact section through a plurality of metal vias, so that light transmitted within the metal contact section is absorbed by the metal vias and transmitted to the metal waveguide.
[0013] The transition waveguide is a ridge waveguide, which includes a ridge and a flat plate portion; wherein, the width of the ridge of the coupling transmission section adjacent to the metal contact section gradually decreases along the extension direction of the transition waveguide toward the metal contact section, forming a ridge tip; the metal contact section includes the flat plate portion but does not include the ridge.
[0014] In some embodiments, the spacing between the transmission waveguide and the absorption waveguide is 10–300 nm; the refractive index of the transmission waveguide is less than that of the absorption waveguide.
[0015] In some embodiments, the absorbing waveguide includes a first absorbing waveguide segment and a second absorbing waveguide segment connected to each other, wherein the second transmitting waveguide segment extends side by side with the first absorbing waveguide segment.
[0016] In some embodiments, the transmission waveguide is a strip waveguide.
[0017] In some embodiments, the transmission waveguide is made of any one of lithium niobate, silicon nitride, silicon, germanium, gallium arsenide, indium phosphide, gallium nitride, zinc oxide, aluminum nitride, and silicon carbide; the absorption waveguide is a doped silicon waveguide.
[0018] To achieve the above objectives, the present invention also provides a photonic integrated chip, including the aforementioned optical waveguide terminator.
[0019] To achieve the above objectives, the present invention also provides an optical communication device, including the aforementioned optical waveguide terminator.
[0020] The technical advantage of this invention is that the optical waveguide terminator of this application has at least one conventional transmission waveguide coiled around its absorbing waveguide and transmission waveguide coupling section with the absorbing waveguide, so as to isolate the optical coupling and optical absorption of the waveguide terminator from other surrounding waveguides, thereby playing a certain isolation role, solving the technical problem of optical crosstalk caused by the terminator to other nearby waveguides, and at the same time avoiding the absorbing waveguide from affecting the optical field of nearby optical waveguides. Attached Figure Description
[0021] 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.
[0022] Figure 1 This is a top view of the optical waveguide terminator provided in Embodiment 1 of this application.
[0023] Figure 2 This is a schematic diagram of the transmission waveguide provided in Embodiment 1 of this application.
[0024] Figure 3 This is a schematic diagram of the absorbing waveguide provided in Embodiment 1 of this application.
[0025] Figure 4 for Figure 1 A cross-sectional view along the AA direction.
[0026] Figure 5 This application provides a schematic diagram of optical field transmission in a transmission waveguide according to Embodiment 1.
[0027] Figure 6 This application provides a schematic diagram of optical field transmission in an absorbing waveguide according to Embodiment 1.
[0028] Figure 7 This is a schematic diagram of the structure of the optical waveguide terminator provided in Embodiment 2 of this application.
[0029] Figure 8 This is an exploded view of the optical waveguide terminator provided in Embodiment 2 of this application.
[0030] Figure 9 This is a schematic diagram of the structure of the optical waveguide terminator provided in Embodiment 3 of this application.
[0031] Figure 10 This is a schematic diagram of the structure of the photonic integrated chip provided in Embodiment 4 of this application.
[0032] The components in the attached diagram are labeled as follows:
[0033] 1-Transmission waveguide; 11-First transmission waveguide segment; 12-Second transmission waveguide segment; 121-Starting position; 122-Ending position;
[0034] 2-Absorbing waveguide; 21-First absorbing waveguide segment; 22-Second absorbing waveguide segment; 210-Starting end; 220-Ending end;
[0035] 100-port;
[0036] 10 - First waveguide layer; 20 - Second waveguide layer; 30 - Cladding;
[0037] 31 - Buried oxygen layer; 32 - First capping layer; 33 - Second capping layer;
[0038] 201 - Transition waveguide; 202 - Metal waveguide; 203 - Metal via;
[0039] 2011 - Coupled transmission section; 2012 - Metal contact section;
[0040] 40-substrate. Detailed Implementation
[0041] 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.
[0042] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.
[0043] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0044] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0045] This application addresses the problem that existing optical waveguide terminators in photonic integrated chips easily cause optical crosstalk to other nearby waveguides, and proposes an optical waveguide terminator, such as... Figure 1 As shown, the optical waveguide terminator includes a transmission waveguide 1 and an absorption waveguide 2. At least one loop of conventional transmission waveguide is wound around the absorption waveguide 2 and the coupling section between the transmission waveguide 1 and the absorption waveguide 2. This isolates stray light that may diffuse when light is coupled from the transmission waveguide 1 to the absorption waveguide 2 and when it propagates within the absorption waveguide 2 within the loop wound around the first transmission waveguide section 11. This avoids optical crosstalk between the optical waveguide terminator and nearby optical waveguide devices, and also prevents the absorption waveguide 2 from affecting the optical field of nearby optical waveguides. Specifically, this will be described in detail in the following embodiments.
[0046] Example 1
[0047] like Figures 1 to 4 As shown, the optical waveguide terminator of this embodiment includes a cladding 30, a first waveguide layer 10 and a second waveguide layer 20 stacked within the cladding 30, a transmission waveguide located in the first waveguide layer 10, and an absorption waveguide 2 located in the second waveguide layer 20.
[0048] In this embodiment, the optical waveguide terminator is disposed in a photonic integrated chip. The cladding 30 includes a buried oxide layer 31 and a first capping layer 32, which are stacked on a substrate 40. A second waveguide layer 20 is disposed on the buried oxide layer 31, a first waveguide layer 10 is disposed on the second waveguide layer 20, and the first capping layer 32 covers both the first waveguide layer 10 and the second waveguide layer 20. In this embodiment, the spacing between the first waveguide layer 10 and the second waveguide layer 20 ranges from 10 to 300 nm, that is, the spacing between the transmission waveguide 1 and the absorption waveguide 2 is 10 to 300 nm, for example, 10 nm, 50 nm, 100 nm, 110 nm, 150 nm, 200 nm, 210 nm, 250 nm, or 300 nm, which can be selected according to the actual needs of the product or the manufacturing process capability.
[0049] Specifically, such as Figure 1 and Figure 2 As shown, the transmission waveguide 1 includes a first transmission waveguide segment 11 and a second transmission waveguide segment 12 connected to each other. Figure 2The dashed line X is the dividing line between the first transmission waveguide segment 11 and the second transmission waveguide segment 12. This dividing line is a virtual boundary, and the actual transmission waveguide 1 is a continuous waveguide. The first transmission waveguide segment 11 is provided with a port 100 for receiving external incident light, which is relatively far away from the second transmission waveguide segment 12. The first transmission waveguide segment 11 is coiled inward from the port 100 at least one turn. In this embodiment, the first transmission waveguide segment 11 is coiled inward one and a half turns. The second transmission waveguide segment 12 is located inside the coil of the first transmission waveguide segment 11. The second transmission waveguide segment 12 is used for optical coupling with the absorption waveguide 2, and the orthographic projection of the second transmission waveguide segment 12 on the second waveguide layer 20 at least partially coincides with the absorption waveguide 2, so as to couple the light transmitted in the transmission waveguide 1 to the absorption waveguide 2. The orthographic projection of the absorption waveguide 2 on the plane where the transmission waveguide 1 is located is located inside the coil of the first transmission waveguide segment 11. The absorption waveguide 2 is used to absorb the light it receives.
[0050] In this embodiment, the first transmission waveguide segment 11 of the transmission waveguide 1 is coiled around the two waveguide coupling segments and the absorption waveguide 2. This isolates stray light that may diverge when light is coupled from the transmission waveguide 1 to the absorption waveguide 2 and when it is transmitted within the absorption waveguide 2 within the coil of the first transmission waveguide segment 11. This avoids the problem of optical crosstalk caused by the light field leaked during the coupling and absorption process within the optical waveguide terminator to nearby optical waveguide devices or other waveguides. At the same time, it avoids the absorption waveguide 2 from affecting the light field of nearby optical waveguides.
[0051] like Figure 1 and Figure 3 As shown, in this embodiment, the absorbing waveguide 2 includes a first absorbing waveguide segment 21 and a second absorbing waveguide segment 22 connected to each other. Figure 3 The dashed line Y in the diagram is the dividing line between the first absorbing waveguide segment 21 and the second absorbing waveguide segment 22. This dividing line is a virtual boundary; in reality, the absorbing waveguide 2 is a continuous waveguide. The end of the first absorbing waveguide segment 21 that is relatively far from the second absorbing waveguide segment 22 is the beginning 210 of the absorbing waveguide 2, and the end of the second absorbing waveguide segment 22 that is relatively far from the first absorbing waveguide segment 21 is the end 220 of the absorbing waveguide 2.
[0052] In this embodiment, the second transmission waveguide segment and the first absorption waveguide segment 21 are two gradient waveguides with opposite gradient trends. In the same plane parallel to the first waveguide layer 10 or the second waveguide layer 20, the orthographic projection of the second transmission waveguide segment 12 and the orthographic projection of the first absorption waveguide segment 21 at least partially overlap, so as to thermally couple the light transmitted in the transmission waveguide 1 to the absorption waveguide 2 for absorption, reduce stray light generated when the transmission waveguide and the absorption waveguide are coupled, and further reduce optical crosstalk to other nearby waveguides.
[0053] like Figure 1As shown, in the same plane parallel to the second waveguide layer 20, the overlap length between the orthographic projection of the second transmission waveguide section 12 and the orthographic projection of the first absorption waveguide section 21 ranges from 50 to 100 μm, for example (unit: μm) 50, 60, 70, 80, 90 or 100. The specific overlap length is designed according to the condition that the second transmission waveguide section 12 and the first absorption waveguide section 21 can better achieve thermally insulating optical coupling.
[0054] Specifically, such as Figures 1 to 4 As shown, the projections of the first absorbing waveguide segment 11 and the second transmitting waveguide segment 12 on the second waveguide layer 20 coincide. The waveguide width of the second transmitting waveguide segment 12 gradually decreases from one end near the first transmitting waveguide segment 11 to the other end. The waveguide width of the first absorbing waveguide segment 21 gradually increases from its beginning to the end near the second absorbing waveguide segment 22 until it is the same size as the second absorbing waveguide segment 22, so that the second transmitting waveguide segment 12 and the first absorbing waveguide segment 21 achieve thermally insulating optical coupling.
[0055] The “waveguide width” mentioned above refers to the width of the cross-sectional dimensions of an optical waveguide.
[0056] like Figure 3 As shown, the waveguide width of the second absorbing waveguide section 22 gradually decreases at the end away from the first absorbing waveguide section 21 to accelerate the consumption of light waves, while reducing light reflection at the tail of the second absorbing waveguide section 22 to prevent reflected light from returning to the transmission waveguide 1.
[0057] like Figures 1 to 4 As shown, in the same plane parallel to the first waveguide layer 10 or the second waveguide layer 20, at the starting position 121 where the orthographic projections of the second transmission waveguide segment 12 and the first absorption waveguide segment 21 overlap, the cross-sectional dimension of the second transmission waveguide segment 12 is larger than the cross-sectional dimension farther from the first absorption waveguide segment 21; at the ending position 122 where the orthographic projections of the second transmission waveguide segment 12 and the first absorption waveguide segment 21 overlap, the cross-sectional dimension of the second transmission waveguide segment 12 is smaller than the cross-sectional dimension of the first absorption waveguide segment 21. Here, "starting position 121" can be understood as the location where the first transmission waveguide segment 11 and the second transmission waveguide segment 12 connect. Here, "ending position 122" can be understood as the end of the second transmission waveguide segment 12.
[0058] Therefore, the optical waveguide terminator provided in this application embodiment can thermally couple the optical field from the second transmission waveguide section 12 to the first absorption waveguide section 21, so that the optical waves are transmitted to the absorption waveguide 2 as much as possible, and are absorbed and annihilated by the absorption waveguide 2 located in the loop of the transmission waveguide.
[0059] In this embodiment, the second transmission waveguide segment 12 and the first absorption waveguide segment 21 are located in the first waveguide layer 10 and the second waveguide layer 20, respectively, and extend side by side vertically. In other embodiments, the second transmission waveguide segment 12 and the first absorption waveguide segment 21 may also extend side by side horizontally in the same waveguide layer.
[0060] In this embodiment, the refractive index of the transmission waveguide 1 is less than that of the absorption waveguide 2, which enables the light wave to be quickly guided into the absorption waveguide 2.
[0061] Specifically, the transmission waveguide 1 can be made of any one of lithium niobate, silicon nitride, silicon, germanium, gallium arsenide, indium phosphide, gallium nitride, zinc oxide, aluminum nitride, and silicon carbide.
[0062] The material of the absorbing waveguide 2 can be a doped silicon waveguide or a metal waveguide. In this embodiment, the absorbing waveguide 2 is a heavily doped waveguide, and the type of the heavily doped waveguide can be N-type or P-type.
[0063] In this embodiment, the absorbing waveguide winds inward from the end coupled to the second transmission waveguide. Thus, the aperture D1 of the transmission waveguide 1 gradually decreases from its outer circle to its inner circle (i.e., in a counter-clockwise direction), and the aperture D2 of the absorbing waveguide 2 also gradually decreases from its outer circle to its inner circle. This arrangement guides the light field to a smaller inner circle region, preventing the area outside the outer circle from being affected by the light field and avoiding optical crosstalk problems caused by the terminator.
[0064] In this embodiment, the transmission waveguide adopts a strip waveguide, which has a stronger ability to confine the optical field. The cross-sectional size of the strip waveguide is smaller, which can reduce the area occupied by the entire optical waveguide terminal.
[0065] like Figures 1 to 3 As shown, in this embodiment, both the transmission waveguide 1 and the absorption waveguide 2 are helical structures. The helical structure is composed of multiple curved waveguide segments connected sequentially. These curved waveguide segments include one or more combinations of Euler curved waveguides, Bessel curved waveguides, sinusoidal curved waveguides, cosine curved waveguides, laterally offset curved waveguides, groove-etched curved waveguides, and centrally widened curved waveguides. These types of curved waveguides, compared to quarter-circular waveguides, can reduce the overall footprint of the device, thus enabling small-sized optical waveguide terminators. Specifically, the laterally offset curved waveguide has a certain misalignment between the input and output of the waveguide (such as transmission waveguide 1 and absorption waveguide 2) and the centrally curved portion; the groove-etched curved waveguide removes the buried layer on one side of the centrally curved portion of the waveguide (such as transmission waveguide 1 and absorption waveguide 2); and the centrally widened curved waveguide gradually increases the waveguide aperture at the centrally curved portion of the waveguide (such as transmission waveguide 1 and absorption waveguide 2).
[0066] In this embodiment, both the transmission waveguide 1 and the absorption waveguide 2 employ multiple sequentially connected Euler bent waveguides. Compared to traditional semi-circular bent waveguides, this allows for a smaller aperture. Specifically, the transmission waveguide 1 is composed of four 180° Euler bent waveguides; the absorption waveguide 2 is composed of five 180° Euler bent waveguides. The use of Euler bent waveguides further reduces the overall footprint of the optical waveguide terminator, thus enabling its miniaturization.
[0067] The optical waveguide terminator of this embodiment uses a transmission waveguide and an absorption waveguide constructed from Euler bent waveguides, which allows the aperture D1 of the transmission waveguide 1 to reach the range of 10 to 15 μm, for example (unit: μm) 10, 11, 12, 13, 14 or 15; the aperture D2 of the absorption waveguide 2 can reach the range of 2 to 10 μm, for example (unit: μm) 2, 3, 4, 5, 6, 7, 8, 9 or 10.
[0068] like Figure 1 , Figure 2 , Figure 3 , Figure 5 and Figure 6 As shown, the transmission of light waves in an optical waveguide terminator can be divided into three stages:
[0069] In the first stage, port 100 of transmission waveguide 1 receives light waves from an external optical waveguide port (not shown) and transmits them stably in the first transmission waveguide segment 11. At this time, the height and width of the first transmission waveguide segment 11 remain constant. Although the first transmission waveguide segment 11 has a bend, its impact on the effective refractive index of the waveguide is minimal. This first transmission waveguide segment 11 acts as a guide to transmit the light waves. The spiral structure of the first transmission waveguide segment 11 guides the light field to the inner region of the spiral structure, preventing the light field from leaking to areas outside the outer ring and causing optical crosstalk.
[0070] In the second stage, light is coupled from transmission waveguide 1 to absorption waveguide 2. Specifically, the first transmission waveguide segment 11 guides the light to the second transmission waveguide 1 located in the inner circle, and then, through the second transmission waveguide 1, it is thermally coupled to the absorption waveguide 2 located in the inner circle. The second transmission waveguide 1 and absorption waveguide 2 are thermally coupled, allowing light waves to gradually couple from the second transmission waveguide segment 12 to the first absorption waveguide segment 21. The first absorption waveguide segment 21 simultaneously transmits and absorbs the light waves, guiding most of the light waves to the second absorption waveguide segment 22, which is located in a smaller area within the inner circle, for absorption. This prevents the leaked light field from causing optical crosstalk to areas outside the outer circle.
[0071] In the third stage, the light wave is transmitted and absorbed in the second absorption waveguide section 22 of the absorption waveguide 2. As the transmission distance increases, the energy of the light wave decreases rapidly, causing the light wave to annihilate and disappear in the second absorption waveguide section 22, thereby eliminating the problem of light wave crosstalk.
[0072] Example 2
[0073] This embodiment provides an optical waveguide terminator, which includes most of the schemes of Embodiment 1. The difference from Embodiment 1 is that in this embodiment, the absorbing waveguide 2 includes a transition waveguide 201 and a metal waveguide 202, and the metal waveguide 202 and the transition waveguide 201 are connected through a plurality of metal vias 203.
[0074] Specifically, such as Figures 7 to 8 As shown, the absorbing waveguide 2 includes a transition waveguide 201 and a metal waveguide 202. The transition waveguide 201 includes a coupled transmission section 2011 and a metal contact section 2012 connected to each other. The coupled transmission section 2011 is used for optical coupling of the second transmission waveguide section 12 to receive and transmit light from the second transmission waveguide section 12. The metal contact section 2012 is a doped waveguide. The metal waveguide 202 is located on at least one side of the metal contact section 201 and is connected to the metal contact section 2012 through a plurality of metal vias 203, so that the light transmitted in the metal contact section 2012 is absorbed by the metal vias 203 and transmitted to the metal waveguide 202. Figure 7 and Figure 8 The diagram shows the metal waveguide 202 located on the lower side of the metal contact section 201. In other embodiments, the metal waveguide 202 may also be located on the upper side or the left and right sides of the metal contact section 201, without any particular limitation.
[0075] Therefore, when the light received by the absorbing waveguide 2 from the transmission waveguide 1 is transmitted through the transition waveguide 201, it will be absorbed by the metal contact section 2012 and the metal via 203 of the transition waveguide 201. The light waves that are not completely absorbed by the metal via 203 will be absorbed by the metal waveguide 202.
[0076] The transition waveguide 201 is a ridge waveguide, comprising a ridge and a planar section. The width of the ridge of the coupling transmission section 2011 adjacent to the metal contact section 2012 gradually decreases along the extension direction of the transition waveguide 201 towards the metal contact section 2012, forming a ridge tip. The metal contact section 2012 includes a planar section but does not have a ridge. It is understood that the ridge ends before the metal via 203, leaving only a thin planar section in contact with the metal via 203. The planar section is relatively thin, resulting in weaker light confinement. Combined with the absorption effect of the metal, the light field is more easily transmitted into the metal via 203, where it is absorbed by both the metal via 203 and the metal waveguide 202.
[0077] Example 3
[0078] This embodiment provides an optical waveguide terminator, which includes most of the solutions in Embodiment 1. The difference from Embodiment 1 is that, in this embodiment, as shown... Figure 9As shown, the absorbing waveguide 2 includes a metal waveguide 202, and the second transmission waveguide segment 12 is connected to the metal waveguide 202 through multiple metal vias 203.
[0079] The absorbing waveguide 2 receives light from the transmission waveguide 1 through the metal via 203, and absorbs the received light through the metal via 203 and the metal waveguide 202. This embodiment omits the transition waveguide, simplifying the structure of the optical waveguide terminator.
[0080] Example 4
[0081] This application also provides a photonic integrated chip, which includes the optical waveguide terminator of the above embodiments. Specifically, as shown... Figure 10 As shown, taking the optical waveguide terminator of Embodiment 2 as an example, the photonic integrated chip includes a first cover layer 32, a first waveguide layer 10, a second waveguide layer 20, and a second cover layer 33. The transmission waveguide 1 of the optical waveguide terminator is located in the first waveguide layer 10, the absorption waveguide 2 is located in the second waveguide layer 20, and the metal waveguide is located within the second cover layer. The first waveguide layer 10 and the second waveguide layer 20 are stacked within the first cover layer 32, with the second waveguide layer relatively adjacent to the metal waveguide. The metal waveguide layer 202 is connected to the absorption waveguide 2 of the second waveguide layer 20 through a metal via 203. The second cover layer 33 covers the metal waveguide layer 202 and is disposed on the first cover layer 32. This photonic integrated chip integrates the optical waveguide terminator of this application, which can effectively solve the problem of optical crosstalk caused by stray light from waveguide termination within the photonic integrated chip. Moreover, the photonic integrated chip process is flexible, facilitating the fabrication of waveguide terminators with various hybrid structures, and is conducive to realizing the waveguide terminator structures of the above embodiments.
[0082] Example 5
[0083] This application also provides an optical module, which includes the photonic integrated chip described in the above embodiments, and can realize a small-sized optical communication device.
[0084] The foregoing has provided a detailed description of an optical waveguide terminal, a photonic integrated chip, and an optical module provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. An optical waveguide terminator, characterized in that, Including transmission waveguides and absorption waveguides; The transmission waveguide includes a first transmission waveguide segment and a second transmission waveguide segment connected to each other. The first transmission waveguide segment is provided with a port for receiving external incident light, and the port is relatively far away from the second transmission waveguide segment. The first transmission waveguide segment is wound inward from the port at least one turn, and the second transmission waveguide segment is located inside the loop wound by the first transmission waveguide segment. The second transmission waveguide segment is used to optically couple with the absorption waveguide to couple the light transmitted in the transmission waveguide to the absorption waveguide. The orthographic projection of the absorbing waveguide onto the plane of the transmission waveguide is located within the loop around which the first transmission waveguide segment is coiled, and the absorbing waveguide is used to absorb the light it receives.
2. The optical waveguide terminator according to claim 1, characterized in that, The optical waveguide terminator includes a cladding and a first waveguide layer and a second waveguide layer stacked within the cladding. The transmission waveguide is located in the first waveguide layer, and the absorption waveguide is located in the second waveguide layer. The orthographic projection of the second transmission waveguide segment onto the second waveguide layer at least partially coincides with the absorption waveguide.
3. The optical waveguide terminator according to claim 2, characterized in that, The absorbing waveguide includes a first absorbing waveguide segment and a second absorbing waveguide segment connected to each other. The end of the first absorbing waveguide segment that is relatively far away from the second absorbing waveguide segment is the beginning of the absorbing waveguide, and the end of the second absorbing waveguide segment that is relatively far away from the first absorbing waveguide segment is the end of the absorbing waveguide. In this configuration, the projections of the first absorbing waveguide segment and the second transmitting waveguide segment onto the second waveguide layer coincide. The waveguide width of the second transmitting waveguide segment gradually decreases from its position near the beginning of the absorbing waveguide to its end, while the waveguide width of the first absorbing waveguide segment gradually increases from its beginning to its end near the second absorbing waveguide segment until it is the same size as the second absorbing waveguide segment. This allows the second transmitting waveguide segment and the first absorbing waveguide segment to achieve thermally insulating optical coupling.
4. The optical waveguide terminator according to claim 3, characterized in that, The length of the projection of the second transmission waveguide segment that overlaps with the first absorption waveguide segment is in the range of 50 to 100 μm.
5. The optical waveguide terminator according to claim 3, characterized in that, The absorbing waveguide is coiled inward from the end coupled to the second transmission waveguide; The cross-sectional dimensions of the second absorbing waveguide segment gradually decrease at the end furthest from the first absorbing waveguide segment.
6. The optical waveguide terminator according to claim 5, characterized in that, Both the transmission waveguide and the absorption waveguide are spiral structures. The spiral structure is composed of multiple curved waveguide segments connected in sequence. The multiple curved waveguide segments include one or more combinations of Euler curved waveguides, Bessel curved waveguides, sine curved waveguides, cosine curved waveguides, laterally offset curved waveguides, groove-etched curved waveguides, and center-widened curved waveguides.
7. The optical waveguide terminator according to claim 1, characterized in that, The absorbing waveguide includes a metal waveguide located on at least one side of the second transmission waveguide segment. The second transmission waveguide segment is connected to the metal waveguide through a plurality of metal vias, so that the light transmitted in the second transmission waveguide segment is absorbed by the metal vias and transmitted to the metal waveguide.
8. The optical waveguide terminator according to claim 2, characterized in that, The absorbing waveguide includes a transition waveguide and a metal waveguide. The transition waveguide includes a coupled transmission section and a metal contact section connected together. The coupled transmission section is used for optical coupling of the second transmission waveguide section to receive and transmit light from the second transmission waveguide section. The metal contact section is a doped waveguide. The metal waveguide is located on at least one side of the metal contact section and is connected to the metal contact section through a plurality of metal vias, so that the light transmitted in the metal contact section is absorbed by the metal vias and transmitted to the metal waveguide.
9. The optical waveguide terminator according to claim 8, characterized in that, The transition waveguide is a ridge waveguide, which includes a ridge and a flat plate portion; wherein, the width of the ridge of the coupling transmission section adjacent to the metal contact section gradually decreases along the extension direction of the transition waveguide toward the metal contact section, forming a ridge tip; the metal contact section includes the flat plate portion but does not have a ridge.
10. The optical waveguide terminator according to claim 2, characterized in that, The spacing between the transmission waveguide and the absorption waveguide is 10–300 nm. The refractive index of the transmission waveguide is less than that of the absorption waveguide.
11. The optical waveguide terminator according to claim 1, characterized in that, The absorbing waveguide includes a first absorbing waveguide segment and a second absorbing waveguide segment connected to each other, with the second transmitting waveguide segment extending side by side with the first absorbing waveguide segment.
12. The optical waveguide terminator according to claim 1, characterized in that, The transmission waveguide is a strip waveguide.
13. The optical waveguide terminator according to claim 1, characterized in that, The transmission waveguide is made of any one of lithium niobate, silicon nitride, silicon, germanium, gallium arsenide, indium phosphide, gallium nitride, zinc oxide, aluminum nitride, and silicon carbide. The absorbing waveguide is a silicon-doped waveguide.
14. A photonic integrated chip, characterized in that, Includes the optical waveguide terminator as described in any one of claims 1-13.
15. An optical module, characterized in that, Includes the optical waveguide terminator as described in any one of claims 1 to 13.