High-isolation integrated optical array chip and manufacturing method thereof
By setting isolation trenches and forming optical isolation layers and isolation metal layers in the lithium niobate integrated optical array chip, the problem of crosstalk between optical and electrical signals is solved, achieving higher isolation and independence.
Patent Information
- Application Number
- CN202510976947.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-16
- Publication Date
- 2025-10-28
AI Technical Summary
In existing lithium niobate integrated optical array chips, crosstalk between optical and electrical signals occurs between integrated optical units, affecting system performance.
An isolation trench is set in the integrated optical array chip, and an optical isolation layer and an isolation metal layer are formed on its bottom and sidewalls. The optical isolation layer absorbs the optical signal radiation mode, and the isolation metal layer absorbs the electrical signal, thereby enhancing the isolation effect between units.
It effectively reduces crosstalk between optical and electrical signals, improves the isolation of the integrated optical array chip, and ensures that each integrated optical unit works independently.
Smart Images
Figure CN120848050A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of microwave photonics and optical sensing, and in particular relates to a high-isolation integrated optical array chip and its fabrication method. Background Technology
[0002] Lithium niobate is widely used in integrated optical devices due to its low material cost, stable mechanical / chemical properties, and good electro-optical properties. It can enhance the optical refractive index of the waveguide region through proton exchange or metal diffusion to form an on-chip weakly confined waveguide. Based on the linear electro-optic effect of lithium niobate, the change in the refractive index of the waveguide caused by the change in the strength of the applied electric field can cause a phase change in the light wave due to the change in refractive index, thereby realizing functions such as electro-optic modulation.
[0003] With the rapid development of applications such as optical communication, optical sensing, and microwave photonics, multi-channel, array-integrated optical chips have become the key to further improving the performance and integration of high-capacity optical communication systems, high-performance optical sensing systems, and broadband microwave photonics systems.
[0004] Lithium niobate integrated optical array chips comprise multiple integrated optical units. Each integrated optical unit needs to maintain independent operating states and characteristics; that is, optical and electrical signals must not crosstalk between different integrated optical units. However, due to the weak confinement characteristics of integrated optical waveguides and the propagation characteristics of alternating electrical signals in the on-chip metal electrode region, the internal optical and electrical signals of an integrated optical unit can radiate and propagate to other units, interfering with their operating states. This disrupts the independence of each integrated optical unit on the array chip and affects system performance. Summary of the Invention
[0005] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a high-isolation integrated optical array chip and its fabrication method.
[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:
[0007] A method for fabricating a high-isolation integrated optical array chip includes the following steps:
[0008] S100, Take a substrate;
[0009] S200: Divide a plurality of optical unit regions on the substrate along a first direction, and divide isolation channel regions between adjacent optical unit regions; the optical unit regions are used to form integrated optical units, and the isolation channel regions are used to form isolation channels;
[0010] S300, forming an isolation trench in the isolation channel region on the substrate;
[0011] S400: Photolithographically pattern the optical isolation layer in the isolation trench area, and use proton exchange or metal ion diffusion process to form the optical isolation layer at the bottom and sidewalls of the isolation trench.
[0012] S500: Photolithographically print the pattern of the isolation metal layer in the isolation channel region, and form the isolation metal layer by depositing a metal film on the optical isolation layer.
[0013] Furthermore, the substrate is a lithium niobate wafer substrate.
[0014] Furthermore, the width of the isolation trench is 5μm to 300μm, and the depth of the isolation trench is 0.1μm to 200μm.
[0015] Furthermore, in step S400, the depth of proton exchange or metal ion diffusion is 2 μm to 10 μm; the width of the formed optical isolation layer is 6 μm to 400 μm.
[0016] Furthermore, in step S500, the thickness of the deposited metal film is 0.1 μm to 50 μm.
[0017] Furthermore, the integrated optical unit includes an integrated optical waveguide and a metal electrode. In step S400, the pattern of the integrated optical waveguide is simultaneously photolithographically etched in the optical unit region during photolithography; when the optical isolation layer is formed using proton exchange or metal ion diffusion processes, the integrated optical waveguide is simultaneously formed in the optical unit region.
[0018] In step S500, the pattern of the metal electrode is simultaneously photolithographically formed in the optical unit region during photolithography; while forming the isolation metal layer by depositing the metal film layer, the metal electrode is simultaneously formed in the optical unit region.
[0019] Furthermore, the width of the integrated optical waveguide is 2μm to 15μm, the depth of the integrated optical waveguide is 2μm to 10μm, and the width of the metal electrode is 1μm to 100μm.
[0020] A high-isolation integrated optical array chip includes a substrate, a plurality of integrated optical units sequentially disposed on the substrate along a first direction, and an isolation channel disposed between adjacent integrated optical units; the isolation channel includes an isolation trench formed on the substrate, an optical isolation layer formed on the bottom and sidewalls of the isolation trench, and an isolation metal layer formed on the optical isolation layer.
[0021] Furthermore, the substrate is a lithium niobate substrate, the width of the isolation trench is 5μm to 300μm, the depth of the isolation trench is 0.1μm to 200μm, the width of the optical isolation layer is 6μm to 400μm, and the isolation metal layer includes a first metal layer covering the bottom of the isolation trench on the optical isolation layer, a second metal layer covering the sidewall of the isolation trench on the optical isolation layer, and a third metal layer extending outward from the upper end of the second metal layer, wherein the thickness of the first metal layer, the second metal layer, and the third metal layer is 0.1μm to 50μm.
[0022] Furthermore, the integrated optical unit includes an integrated optical waveguide and a metal electrode. The width of the integrated optical waveguide is 2μm to 15μm, and the depth of the integrated optical waveguide is 2μm to 10μm. The width of the metal electrode is 1μm to 100μm, and the layer thickness of the metal electrode is 0.1μm to 50μm.
[0023] In this invention, an isolation channel is formed using an optical isolation layer and an isolation metal layer. The optical isolation layer absorbs the radiation modes generated by the integrated optical waveguides in adjacent integrated optical units, thereby significantly reducing the interference of these radiation modes on the optical signals of other integrated optical units in the integrated optical array chip. Similarly, the isolation metal layer absorbs and attenuates the radiated electrical signals from the metal electrodes in adjacent integrated optical units, thereby significantly reducing the interference of these radiated electrical signals on the electrical signals of other integrated optical units in the integrated optical array chip. Furthermore, by first creating isolation trenches and then forming the optical isolation layer and isolation metal layer based on these trenches, the depth of the isolation channel can be increased, resulting in better isolation performance. Moreover, the optical isolation layer and integrated optical waveguides can be formed simultaneously, as can the isolation metal layer and metal electrodes, without requiring additional processing steps. Attached Figure Description
[0024] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:
[0025] Figure 1 This is a schematic diagram of the structure of an existing lithium niobate integrated optical array chip.
[0026] Figure 2 This is a flowchart of an embodiment of the method for fabricating a high-isolation integrated optical array chip according to the present invention.
[0027] Figure 3 This is a schematic diagram showing the division of the optical unit region and the isolation channel region on the substrate.
[0028] Figure 4 This is a schematic diagram after the isolation trenches have been formed on the substrate.
[0029] Figure 5 This is a schematic diagram showing the formation of the optical isolation layer and integrated optical waveguide.
[0030] Figure 6 This is a schematic diagram showing the formation of the insulating metal layer and the metal electrode.
[0031] The diagrams in the instruction manual are labeled as follows:
[0032] Substrate-100; Optical unit region-110; Isolation channel region-120; Isolation channel-200; Isolation trench-210; Optical isolation layer-220; Isolation metal layer-230; First metal layer-231; Second metal layer-232; Third metal layer-233; Integrated optical unit-300; Integrated optical waveguide-310; Metal electrode-320; Input fiber optic assembly-400; Output fiber optic assembly-500. Detailed Implementation
[0033] The following specific examples illustrate the implementation of the present invention. The illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0034] like Figure 1 As shown, the lithium niobate integrated optical array chip includes multiple integrated optical units 300 formed on a lithium niobate substrate 100. Each integrated optical unit 300 realizes the input and output of optical signals through an input optical fiber assembly 400 and an output optical fiber assembly 500, respectively. Each integrated optical unit 300 is relatively independent, and its structure and function can be different. Each integrated optical unit 300 includes an integrated optical waveguide 310 with a specific pattern and a metal electrode 320, thereby constituting each integrated optical unit 300 with relatively independent functions.
[0035] Please see Figure 2 , Figure 2 This is a flowchart illustrating an embodiment of the fabrication method for the high-isolation integrated optical array chip of the present invention. The fabrication method of the high-isolation integrated optical array chip in this embodiment includes the following steps:
[0036] S100, Take a substrate 100. In this embodiment, the substrate 100 is a lithium niobate wafer substrate.
[0037] S200, please refer to Figure 3 A plurality of optical unit regions 110 are divided on the substrate 100 along a first direction, and isolation channel regions 120 are divided between adjacent optical unit regions 110. The optical unit regions 110 are used to form integrated optical units 300, and the isolation channel regions 120 are used to form isolation channels 200.
[0038] S300, please refer to Figure 4 An isolation trench 210 is formed in the isolation channel region 120 on the substrate 100. By providing the isolation trench 210, the depth of the isolation channel 200 can be increased, thereby achieving better isolation between adjacent integrated optical units 300. The isolation trench 210 is generally formed by precision etching or cutting processes, and the width of the isolation trench 210 is generally 5μm to 300μm, and the depth of the isolation trench 210 is generally 0.1μm to 200μm.
[0039] S400, please refer to Figure 5 In the isolation channel region 120, the pattern of the optical isolation layer 220 is photolithographically etched, and the optical isolation layer 220 is formed on the bottom and sidewalls of the isolation trench 210 using proton exchange or metal ion diffusion processes. By using proton exchange or metal ion diffusion processes, the optical refractive index of the relevant region can be increased by changing the chemical composition and ratio of the lithium niobate material, thereby forming the integrated optical waveguide 310 and the optical isolation layer 220 in the integrated optical waveguide 310 region and the isolation channel region 120, respectively. Of course, after this step, the photoresist will be removed; the photolithography process is existing technology and will not be described in detail here.
[0040] In this step, the depth of proton exchange or metal ion diffusion is generally 2 μm to 10 μm; the width of the formed optical isolation layer 220 is generally 6 μm to 400 μm. Of course, since the integrated optical unit 300 includes an integrated optical waveguide 310 and a metal electrode 320, the integrated optical waveguide 310 can also be formed simultaneously in this step. The specific method is as follows:
[0041] During the patterning of the optical isolation layer 220, the pattern of the integrated optical waveguide 310 is simultaneously patterned in the optical unit region 110. When the optical isolation layer 220 is formed using proton exchange or metal ion diffusion processes, the integrated optical waveguide 310 is simultaneously formed in the optical unit region 110. The width of the integrated optical waveguide 310 is 2 μm to 15 μm, and the depth of the integrated optical waveguide 310 is determined by the depth of the proton exchange or metal ion diffusion process.
[0042] S500, please refer to Figure 6The isolation metal layer 230 is patterned by photolithography in the isolation trench region 120, and the isolation metal layer 230 is formed on the optical isolation layer 220 by depositing a metal film layer; the isolation trench 210, the optical isolation layer 220, and the isolation metal layer 230 form an isolation channel 200. Of course, the photoresist will be removed after this step. The isolation metal layer 230 includes a first metal layer 231 covering the bottom of the optical isolation layer 220, a second metal layer 232 covering the sidewalls of the optical isolation layer 220, and a third metal layer 233 extending outward from the upper end of the second metal layer 232. A metal electrode 320 can also be formed in this step. The specific method is as follows:
[0043] During the photolithography of the isolation metal layer 230, the pattern of the metal electrode 320 is simultaneously photolithographically formed in the optical unit region 110. After depositing the metal film, the metal film deposited at the pattern of the isolation metal layer 230 forms the isolation metal layer 230, and the metal film deposited at the pattern of the metal electrode 320 forms the metal electrode 320. The integrated optical waveguide 310 and the metal electrode 320 form the integrated optical unit 300. The width of the metal electrode 320 is 1 μm to 100 μm, and the thickness of the metal film is the thickness of the metal electrode 320.
[0044] In this step, the thickness of the deposited metal film is 0.1 μm to 50 μm, that is, the thickness of the first metal layer 231, the second metal layer 232, the third metal layer 233, and the metal electrode 320 is all 0.1 μm to 50 μm. Since the second metal layer 232 is vertically arranged, the thickness of the second metal layer 232 refers to its thickness in the horizontal direction, while the thickness of the first metal layer 231, the third metal layer 233, and the metal electrode 320 refers to their thickness in the vertical direction.
[0045] Following this step, an input fiber optic assembly 400 and an output fiber optic assembly 500 will be installed at both ends of each integrated optical unit 300. These are existing process steps and will not be described in detail here.
[0046] In this embodiment, an optical isolation layer 220 and an isolation metal layer 230 are used to form the isolation channel 200. The optical isolation layer 220 can absorb the radiation mode generated by the integrated optical waveguide 310 in the adjacent integrated optical unit 300, thereby significantly reducing the interference of the radiation mode on the optical signals of other integrated optical units 300 in the integrated optical array chip. The isolation metal layer 230 can absorb and attenuate the radiated electrical signal of the metal electrode 320 in the adjacent integrated optical unit 300, thereby significantly reducing the interference of the radiated electrical signal on the electrical signals of other integrated optical units 300 in the integrated optical array chip. In addition, by first setting the isolation trench 210 and then forming the optical isolation layer 220 and the isolation metal layer 230 based on the isolation trench 210, the depth of the isolation channel 200 can be increased, thereby achieving a better isolation effect. Moreover, the optical isolation layer 220 and the integrated optical waveguide 310 can be formed simultaneously, and the isolation metal layer 230 and the metal electrode 320 can be formed simultaneously without the need for additional process steps.
[0047] Please continue reading. Figure 6 The present invention also discloses a high-isolation integrated optical array chip. The high-isolation integrated optical array chip of this embodiment includes a substrate 100, a plurality of integrated optical units 300 sequentially disposed on the substrate 100 along a first direction, and an isolation channel 200 disposed between adjacent integrated optical units 300. The substrate 100 is a lithium niobate substrate 100.
[0048] The integrated optical unit 300 includes an integrated optical waveguide 310 and a metal electrode 320. The width of the integrated optical waveguide 310 is 2 μm to 15 μm, and the depth of the integrated optical waveguide 310 is 2 μm to 10 μm. The width of the metal electrode 320 is 1 μm to 100 μm, and the layer thickness of the metal electrode 320 is 0.1 μm to 50 μm. The shapes of the integrated optical waveguide 310 and the metal electrode 320 in each integrated optical unit 300 can be different.
[0049] The isolation channel 200 includes an isolation trench 210 formed on the substrate 100, an optical isolation layer 220 formed on the bottom and sidewalls of the isolation trench 210, and an isolation metal layer 230 formed on the optical isolation layer 220. The isolation trench 210 is generally formed by precision etching or cutting processes, and the width of the isolation trench 210 is generally 5μm to 300μm, and the depth of the isolation trench 210 is generally 0.1μm to 200μm.
[0050] The integrated optical waveguide 310 and the optical isolation layer 220 are formed on the bottom and sidewalls of the isolation trench 210 using a combination of photolithography and proton exchange or metal ion diffusion processes. The width of the optical isolation layer 220 is 6 μm to 400 μm; the depth of the proton exchange or metal ion diffusion is generally 2 μm to 10 μm.
[0051] The metal electrode 320 and the isolation metal layer 230 are formed by a metal film deposition process. The isolation metal layer 230 includes a first metal layer 231 covering the optical isolation layer 220 at the bottom of the isolation trench 210, a second metal layer 232 covering the optical isolation layer 220 on the sidewall of the isolation trench 210, and a third metal layer 233 extending outward from the upper end of the second metal layer 232. The thickness of the first metal layer 231, the second metal layer 232 and the third metal layer 233 are all 0.1 μm to 50 μm.
[0052] In this embodiment, an isolation channel 200 can be formed by the optical isolation layer 220 and the isolation metal layer 230, thereby absorbing the radiation mode generated by the integrated optical waveguide 310 in the adjacent integrated optical unit 300, and absorbing and attenuating the radiated electrical signal of the metal electrode 320 in the integrated optical unit 300, thereby significantly reducing the crosstalk between the optical signals and radiated electrical signals between the integrated optical units 300 in the integrated optical array chip; and achieving a higher degree of isolation between the integrated optical units 300.
[0053] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.
Claims
1. A method for fabricating a high-isolation integrated optical array chip, characterized in that, Includes the following steps: S100, Take a substrate; S200: Divide a plurality of optical unit regions on the substrate along a first direction, and divide isolation channel regions between adjacent optical unit regions; the optical unit regions are used to form integrated optical units, and the isolation channel regions are used to form isolation channels; S300, forming an isolation trench in the isolation channel region on the substrate; S400: Photolithographically pattern the optical isolation layer in the isolation trench area, and use proton exchange or metal ion diffusion process to form the optical isolation layer at the bottom and sidewalls of the isolation trench. S500: Photolithographically print the pattern of the isolation metal layer in the isolation channel region, and form the isolation metal layer by depositing a metal film on the optical isolation layer.
2. The method for fabricating a high-isolation integrated optical array chip as described in claim 1, characterized in that: The substrate is a lithium niobate wafer substrate.
3. The method for fabricating a high-isolation integrated optical array chip as described in claim 1, characterized in that: The width of the isolation trench is 5μm to 300μm, and the depth of the isolation trench is 0.1μm to 200μm.
4. The method for fabricating a high-isolation integrated optical array chip as described in claim 1, characterized in that: In step S400, the depth of proton exchange or metal ion diffusion is 2 μm to 10 μm; the width of the formed optical isolation layer is 6 μm to 400 μm.
5. The method for fabricating a high-isolation integrated optical array chip as described in claim 1, characterized in that: In step S500, the thickness of the deposited metal film is 0.1 μm to 50 μm.
6. The method for fabricating a high-isolation integrated optical array chip as described in any one of claims 1 to 5, characterized in that: The integrated optical unit includes an integrated optical waveguide and a metal electrode. In step S400, the pattern of the integrated optical waveguide is simultaneously photolithographically etched in the optical unit region during photolithography. When the optical isolation layer is formed using proton exchange or metal ion diffusion processes, the integrated optical waveguide is simultaneously formed in the optical unit region. In step S500, the pattern of the metal electrode is simultaneously photolithographically formed in the optical unit region during photolithography; while the isolation metal layer is formed by depositing a metal film layer, the metal electrode is simultaneously formed in the optical unit region.
7. The method for fabricating a high-isolation integrated optical array chip as described in claim 6, characterized in that: The width of the integrated optical waveguide is 2μm to 15μm, the depth of the integrated optical waveguide is 2μm to 10μm, and the width of the metal electrode is 1μm to 100μm.
8. A high-isolation integrated optical array chip, characterized in that: The device includes a substrate, a plurality of integrated optical units sequentially disposed on the substrate along a first direction, and an isolation channel disposed between adjacent integrated optical units; the isolation channel includes an isolation trench formed on the substrate, an optical isolation layer formed on the bottom and sidewalls of the isolation trench, and an isolation metal layer formed on the optical isolation layer.
9. The high-isolation integrated optical array chip as described in claim 8, characterized in that: The substrate is a lithium niobate substrate, the width of the isolation trench is 5μm to 300μm, and the depth of the isolation trench is 0.1μm to 200μm; The width of the optical isolation layer is 6μm to 400μm; the isolation metal layer includes a first metal layer covering the bottom of the isolation trench, a second metal layer covering the sidewall of the isolation trench, and a third metal layer extending outward from the upper end of the second metal layer, wherein the thickness of the first metal layer, the second metal layer, and the third metal layer is 0.1μm to 50μm.
10. The high isolation integrated optical array chip as described in claim 8, characterized in that: The integrated optical unit includes an integrated optical waveguide and a metal electrode. The width of the integrated optical waveguide is 2μm to 15μm and the depth of the integrated optical waveguide is 2μm to 10μm. The width of the metal electrode is 1μm to 100μm and the layer thickness of the metal electrode is 0.1μm to 50μm.