Electro-optical modulation structure with high modulation efficiency

Abstract

The invention discloses an electro-optical modulation structure with high modulation efficiency, which comprises a ground electrode, a signal electrode, an optical waveguide and a substrate, and is characterized in that the ground electrode, the signal electrode and the optical waveguide are all arranged on the substrate, the optical waveguide is positioned between the ground electrode and the signal electrode, and the electrode materials of the ground electrode and the signal electrode are near-zero refractive index electrode materials; the ground electrode and the signal electrode are used for generating an electric field acting on the optical waveguide, so that the electro-optical characteristic of the optical waveguide is changed. The embodiment of the invention is simple in structure, can effectively improve the electro-optical modulation efficiency, and can be widely applied to the technical field of electro-optical modulation.

Description

Technical Field

[0001] The present invention relates to the technical field of electro-optic modulation, and in particular to an electro-optic modulation structure with high modulation efficiency. Background Art

[0002] Electro-optic modulation is widely used in modern optoelectronic technology and is a key technology for integrated photonic chips. Its function is to control optical signals by applying electrical signals. The efficiency of electro-optic modulation determines the rate at which optical chips can process signals.

[0003] In electro-optic modulators, electrodes play a vital role. Electric fields are generated by applying voltage to the electrodes. Under the same voltage, the smaller the distance between the electrodes, the greater the electric field strength. The electric field acts on the electro-optic material. According to the linear electro-optic effect (Pockels effect) or the carrier dispersion effect, the electric field causes the refractive index of the material to change, thereby achieving the regulation of light-related properties. At the same time, the electrodes will affect the light waves propagating in the optical waveguide. The design of the electrodes, including their material, length and structure, has a direct impact on the modulation efficiency of the modulator.

[0004] The difficulty in electrode design in electro-optic modulators lies in the fact that there are many variable parameters of electrodes and optical waveguides, and in some parameters, low half-wave voltage and high electro-optical bandwidth are mutually constrained, making it difficult to improve modulation efficiency. The main constraints are: (1) When the optical waveguide structure is constant, reducing the distance between the signal electrode and the ground electrode can increase the electric field strength generated by the electrode and improve the modulation efficiency of the modulator. However, due to the limited restriction of the optical waveguide on light, part of the light will enter the electrode and cause absorption loss. Therefore, the electrode needs to maintain a certain distance from the optical waveguide, that is, the signal electrode and the ground electrode cannot be too close. (2) The electric field generated by the electrode is unevenly distributed, which will affect the electro-optical interaction and is not conducive to achieving high modulation efficiency. (3) Increasing the length of the modulation distance can reduce the half-wave voltage, but increasing the modulation distance means more microwave loss. In addition, when the electrode spacing is small, the width of the signal electrode needs to be reduced to meet the electrode impedance matching. The reduction in the cross-sectional area of ​​the electrode will lead to an increase in conductor loss, which further increases the microwave loss.

[0005] Currently, strong electro-optical interaction is mainly achieved by using electrodes with special structures to form a small electrode spacing, while almost no additional microwave loss is introduced. However, this type of solution requires electrodes with relatively complex structures and it is difficult to reduce absorption losses, which affects the electro-optical modulation efficiency. Summary of the invention

[0006] In order to solve the above technical problems, the object of the present invention is to provide an electro-optical modulation structure with simple structure and high electro-optical modulation efficiency.

[0007] The first technical solution adopted by the present invention is:

[0008] An electro-optical modulation structure with high modulation efficiency comprises a ground electrode, a signal electrode, an optical waveguide and a substrate, wherein:

[0009] The ground electrode, the signal electrode and the optical waveguide are all arranged on the substrate, the optical waveguide is located between the ground electrode and the signal electrode, the electrode materials of the ground electrode and the signal electrode are both near-zero refractive index electrode materials, and the ground electrode and the signal electrode are used to generate an electric field to act on the optical waveguide, so that the electro-optical characteristics of the optical waveguide are changed.

[0010] Furthermore, the optical waveguide is a ridge-shaped optical waveguide, which includes a convex ridge and a first side wing and a second side wing located on both sides of the convex ridge. The ridge-shaped optical waveguide is arranged on the upper surface of the substrate, the ground electrode is arranged on the upper surface of the first side wing, and the signal electrode is arranged on the upper surface of the second side wing.

[0011] Furthermore, the optical waveguide is a ridge-shaped optical waveguide, which includes a convex ridge and a first side wing and a second side wing located on both sides of the convex ridge. The ground electrode, the signal electrode and the ridge-shaped optical waveguide are all arranged on the upper surface of the substrate, the ground electrode is arranged close to the side of the first side wing, and the signal electrode is arranged close to the side of the second side wing.

[0012] Furthermore, the optical waveguide is a rectangular optical waveguide, the ground electrode, the signal electrode and the rectangular optical waveguide are all arranged on the upper surface of the substrate, the ground electrode is arranged close to the first side of the rectangular optical waveguide, and the signal electrode is arranged close to the second side of the rectangular optical waveguide.

[0013] Furthermore, the optical waveguide is a ridge-shaped optical waveguide, which includes a convex ridge and a first side wing and a second side wing located on both sides of the convex ridge. The ridge-shaped optical waveguide is arranged on the upper surface of the substrate, the upper surface of the first side wing is provided with a first buffer layer, the ground electrode is arranged on the first buffer layer, the upper surface of the second side wing is provided with a second buffer layer, and the signal electrode is arranged on the second buffer layer.

[0014] Furthermore, the refractive index of the first buffer layer and the second buffer layer are between the refractive index of the ridge optical waveguide and the refractive index of the ground electrode / the signal electrode, and the first buffer layer and the second buffer layer are used to achieve group refractive index matching of the ground electrode, the signal electrode and the ridge optical waveguide.

[0015] The beneficial effects of the present invention are as follows: the present invention provides an electro-optical modulation structure with high modulation efficiency, comprising a ground electrode, a signal electrode, an optical waveguide and a substrate, wherein the ground electrode, the signal electrode and the optical waveguide are all arranged on the substrate, the optical waveguide is located between the ground electrode and the signal electrode, the electrode materials of the ground electrode and the signal electrode are both near-zero refractive index electrode materials, the ground electrode and the signal electrode are used to generate an electric field acting on the optical waveguide, so that the electro-optical properties of the optical waveguide are changed. The embodiment of the present invention has a simple structure and adopts a near-zero refractive index material to make the electrode. The light propagating in the optical waveguide can enter the electrode only when it is perpendicular to the electrode surface. Therefore, most of the light in the optical waveguide cannot enter the electrode, which can greatly reduce the absorption loss of the electrode to the light, so that the ground electrode and the signal electrode can be very close to the optical waveguide without increasing the absorption loss of the electrode to the light, and there is no need to increase the thickness of the buffer layer to avoid excessive absorption loss, thereby effectively improving the electro-optical modulation efficiency; the high directional radiation of the near-zero refractive index material can concentrate the electric field in the direction perpendicular to the surface, provide a strong electric field, and further improve the electro-optical modulation efficiency; in order to meet the impedance matching, the electrode width needs to be reduced while the electrode spacing becomes smaller, and the near-zero refractive index material can achieve low-loss transmission. Therefore, the use of the near-zero refractive index material as the electrode can make the microwave loss not too large when the electrode width is small, further improving the electro-optical modulation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic structural diagram of an electro-optical modulation structure with high modulation efficiency provided by an embodiment of the present invention;

[0017] Figure 2 Another structural schematic diagram of an electro-optical modulation structure with high modulation efficiency provided by an embodiment of the present invention;

[0018] Figure 3 Another structural schematic diagram of an electro-optical modulation structure with high modulation efficiency provided by an embodiment of the present invention;

[0019] Figure 4 Another structural schematic diagram of an electro-optical modulation structure with high modulation efficiency provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The step numbers in the following embodiments are only provided for the convenience of explanation and description, and the order between the steps is not limited in any way. The execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0021] In the description of the present invention, the meaning of "a plurality" is more than two. If there is a description of "a first" or "a second", it is only used to distinguish the technical features, and it cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features. In addition, unless otherwise defined, all technical and scientific terms used in this article have the same meaning as those commonly understood by those skilled in the art. The terms used in this specification are only for describing specific embodiments, not for limiting the present invention.

[0022] First, the principle of electro-optical modulation is explained.

[0023] Electrodes of electro-optic modulators can be divided into lumped type and traveling wave type. Currently, metals (such as gold, aluminum, etc.) are commonly used as electrode materials in electro-optic modulators. Changes in the refractive index of the optical waveguide will cause changes in the phase, amplitude, polarization, etc. of the light waves propagating therein. Therefore, light can be regulated by regulating the refractive index of the optical waveguide. At present, on-chip electro-optic modulators can be realized on optoelectronic integrated platforms of different materials. According to the principle, they can be mainly divided into two types: one is to realize electro-optic modulation using the linear electro-optic effect, and the other is to realize electro-optic modulation using the carrier dispersion effect.

[0024] Based on the linear electro-optic effect: In non-centrosymmetric materials (such as certain crystals), an external electric field will cause the material's refractive index to change, and this change is proportional to the electric field strength. Therefore, light can be regulated by changing the external electric field. The lithium niobate electro-optic modulator that can currently achieve better modulation effects uses this principle.

[0025] Based on the carrier dispersion effect: the change in the concentration of free carriers in the material can lead to a change in the refractive index. By designing different electrical structures, the carrier concentration can be changed, and then the refractive index of the optical waveguide can be changed, thereby achieving the regulation of light in the optical waveguide. The currently common silicon-based electro-optical modulator uses this principle.

[0026] Reference Figures 1 to 4 The present invention provides an electro-optical modulation structure with high modulation efficiency, comprising a ground electrode, a signal electrode, an optical waveguide and a substrate, wherein:

[0027] The ground electrode, signal electrode and optical waveguide are all arranged on the substrate, and the optical waveguide is located between the ground electrode and the signal electrode. The electrode materials of the ground electrode and the signal electrode are both near-zero refractive index electrode materials. The ground electrode and the signal electrode are used to generate an electric field to act on the optical waveguide, so that the electro-optical properties of the optical waveguide change.

[0028] Specifically, the electro-optic modulation structure of the embodiment of the present invention includes a ground electrode (101), a signal electrode (102), an optical waveguide (103), and a substrate (201). The optical waveguide and the electrode are placed on the substrate. The electrode is used to generate the electric field required for electro-optic modulation. The electrode material is a near-zero refractive index material whose real part of the refractive index is close to zero, which is different from the currently commonly used metal electrode material.

[0029] Near-zero refractive index materials have broad application prospects in electromagnetic wave manipulation, new antennas and optical waveguide devices, nonlinear optics, optical absorption, electro-optical modulation and other fields due to their special electromagnetic / optical properties.

[0030] The electromagnetic / optical properties of a material are related to the dielectric constant, magnetic permeability and electrical conductivity of the material, which together determine the interaction between electromagnetic waves / light waves and the material. Near-zero refractive index materials can be divided into single near-zero materials and double near-zero materials. The dielectric constant or magnetic permeability of a single near-zero material is close to zero, while the dielectric constant and magnetic permeability of a double near-zero material are both close to zero. Complex dielectric constant of a medium Complex refractive index Depend on Knowable A near-zero index material has a real part of its refractive index close to zero.

[0031] Refraction and reflection characteristics of electromagnetic waves in near-zero refractive index materials:

[0032] 1) When light is incident from a near-zero refractive index material into air, that is, n i ≈0, n0=1, for any incident angle θ i All of them have θ0 = 0. If the wave source is placed in a near-zero refractive index material, the electromagnetic waves will be emitted vertically from the near-zero refractive index surface and maintain good directivity. This phenomenon is called the high directional radiation effect of near-zero refractive index materials.

[0033] 2) When light is incident from air to a material with a near-zero refractive index, n i =1 and n0≈0, then the critical angle of total reflection Only θ i An incident wave with a refractive index of ≈0, that is, incident perpendicularly to the surface of the near-zero refractive index material, can be transmitted into the near-zero refractive index material.

[0034] In summary, only light perpendicular to the interface can enter the near-zero refractive index material, and when light is emitted from the near-zero refractive index material, its emission direction is perpendicular to the surface.

[0035] Electromagnetic properties of near-zero refractive index materials: The wavelength of electromagnetic waves in near-zero refractive index materials is infinite, the propagation phase is close to zero, and the phase of electromagnetic waves is uniform throughout the material. Studies have shown that under certain conditions, this uniform phase distribution can cause the electromagnetic field to accumulate in certain areas of the material, thereby enhancing the electric field, which can be used to create high-density electric field areas, which is conducive to enhancing the interaction between light and matter.

[0036] Propagation loss of near-zero refractive index materials: Microwave transmission loss will significantly reduce the modulation bandwidth and modulation efficiency, especially for long traveling wave modulators. Microwave loss can be divided into conductor loss and dielectric loss, among which conductor loss is caused by the electrode. The skin effect of the conductor will produce large conductor loss. The skin effect refers to the uneven distribution of current density inside the conductor in a high-frequency electromagnetic field. The current is mainly concentrated in a thin layer near the surface of the conductor, while the current density inside the conductor is very small, almost zero. This uneven current distribution increases the propagation resistance of electromagnetic waves in the conductor. The effective propagation path of the electromagnetic wave is limited to a thin layer on the surface of the conductor, which is equivalent to shortening the propagation path of the electromagnetic wave in the conductor, thereby increasing the propagation loss per unit length. The conductor loss is determined by the electrode material and size. The width w of the signal electrode is s The smaller it is, the larger the electrode spacing d is, and the greater the loss is.

[0037] Near-zero refractive index materials can reduce radiation loss through special design. For example, by adjusting the geometric parameters and structure of the material, the coupling between the propagation mode and the radiation mode of the electromagnetic wave in the material can be weakened, thereby reducing the loss. In some near-zero refractive index materials, special modes such as bound states in the continuum can exist. These modes can propagate in the material without radiating to the external space, so very low propagation losses can be achieved. By precisely designing the microstructure of the near-zero refractive index material, the propagation path of the electromagnetic wave can be optimized, the electromagnetic wave can be evenly distributed, and the propagation loss can be reduced.

[0038] From the above content, it can be seen that since only light perpendicular to the electrode surface can enter the near-zero refractive index electrode, the two electrodes in the electro-optical modulation structure of the embodiment of the present invention can be very close, thereby generating a strong electric field and achieving high modulation efficiency. This is different from the existing electro-optical modulation structure in which the signal electrode and the ground electrode need to be at a certain distance from the optical waveguide to avoid excessive electrode absorption loss.

[0039] The near-zero refractive index electrode in the embodiment of the present invention can concentrate the electric field in a direction perpendicular to the electrode surface, so that a strong electric field between the two electrodes acts on the optical waveguide, thereby improving the electro-optical modulation efficiency.

[0040] When the electrode spacing is reduced, the width of the signal electrode needs to be reduced to meet the impedance matching of the traveling wave electrode, which reduces the cross-sectional area of ​​the electrode and increases the conductor loss. Through proper design and manufacturing, the near-zero refractive index material can achieve lower propagation loss than traditional materials. The near-zero refractive index electrode in the present invention can reduce the microwave loss of the electro-optical modulation structure.

[0041] The electro-optic modulation structure with high modulation efficiency of the embodiment of the present invention is applicable to both lumped electrodes and traveling wave electrodes.

[0042] The following is combined with Figures 1 to 4 The electro-optic modulation structure of the embodiment of the present invention is described in detail.

[0043] Reference Figure 1 As an optional embodiment, the optical waveguide is a ridge optical waveguide, the ridge optical waveguide includes a convex ridge (1033) and a first side wing (1031) and a second side wing (1032) located on both sides of the convex ridge (1033), the ridge optical waveguide is arranged on the upper surface of the substrate (201), the ground electrode (101) is arranged on the upper surface of the first side wing (1031), and the signal electrode (102) is arranged on the upper surface of the second side wing (1032).

[0044] Specifically, the embodiment of the present invention shows a schematic cross-sectional view perpendicular to the light propagation direction of the first electro-optical modulation structure with high modulation efficiency, comprising a substrate (201), a ground electrode (101), a signal electrode (102), and a ridge optical waveguide disposed on the substrate. The ridge optical waveguide has a limiting effect on light, so that the light is mainly concentrated on the ridge of the ridge optical waveguide for propagation. The signal electrode (102) and the ground electrode (101) are made of near-zero refractive index material. When the two electrodes are close to each other, the light propagating in the ridge optical waveguide can hardly enter the electrode, which effectively reduces the absorption loss of light and achieves high modulation efficiency. Applying a voltage to the near-zero refractive index signal electrode (102) can generate a strong electric field, which can change the electro-optical properties (mainly the refractive index for electro-optical modulation) of the optical waveguide (103) between the signal electrode (102) and the ground electrode (101), thereby changing the transmission properties of light in the optical waveguide and achieving efficient electro-optical modulation. The near-zero refractive index electrodes (101, 102) can achieve smaller microwave transmission loss, which is beneficial to improving the electro-optical modulation efficiency.

[0045] Reference Figure 2As an optional embodiment, the optical waveguide is a ridge optical waveguide, which includes a convex ridge (1033) and a first side wing (1031) and a second side wing (1032) located on both sides of the convex ridge (1033). The ground electrode (101), the signal electrode (102) and the ridge optical waveguide are all arranged on the upper surface of the substrate (201), the ground electrode (101) is arranged close to the side of the first side wing (1031), and the signal electrode (102) is arranged close to the side of the second side wing (1032).

[0046] Specifically, the embodiment of the present invention shows a schematic cross-sectional view perpendicular to the light propagation direction of a second electro-optical modulation structure with high modulation efficiency, comprising a substrate (201), a ground electrode (101) and a signal electrode (102) disposed on the substrate, and a ridge optical waveguide disposed between the two electrodes. The ridge optical waveguide has a limiting effect on light, so that the light is mainly concentrated on the ridge of the ridge optical waveguide for propagation. The signal electrode (102) and the ground electrode (101) are made of near-zero refractive index materials. When the distance between the two electrodes is relatively close, the light propagating in the ridge optical waveguide can hardly enter the electrodes, effectively reducing the absorption loss of light and achieving high modulation efficiency. Applying a voltage to the near-zero refractive index signal electrode (102) can generate a strong electric field, which can change the electro-optical properties (mainly the refractive index for electro-optical modulation) of the optical waveguide (103) between the signal electrode (102) and the ground electrode (101), thereby changing the transmission properties of light in the optical waveguide and achieving high-efficiency electro-optical modulation. The near-zero refractive index electrodes (101, 102) can achieve smaller microwave transmission loss, which is beneficial to improving the electro-optical modulation efficiency.

[0047] Reference Figure 3 As an optional embodiment, the optical waveguide is a rectangular optical waveguide (103), the ground electrode (101), the signal electrode (102) and the rectangular optical waveguide (103) are all arranged on the upper surface of the substrate (201), the ground electrode (101) is arranged close to the first side of the rectangular optical waveguide (103), and the signal electrode (102) is arranged close to the second side of the rectangular optical waveguide (103).

[0048] Specifically, the embodiment of the present invention shows a schematic cross-sectional view perpendicular to the light propagation direction of a third electro-optical modulation structure with high modulation efficiency, comprising a substrate (201), a ground electrode (101), a signal electrode (102), and a rectangular optical waveguide (103) disposed on the substrate. The rectangular optical waveguide (103) has a certain limiting effect on the light propagating therein. The signal electrode (102) and the ground electrode (101) are made of near-zero refractive index materials. When the two electrodes are close to each other, the light propagating in the rectangular optical waveguide (103) can hardly enter the electrodes, effectively reducing the absorption loss of light and achieving high modulation efficiency. Applying a voltage to the near-zero refractive index signal electrode (102) can generate a strong electric field, which can change the electro-optical properties (mainly the refractive index for electro-optical modulation) of the optical waveguide (103) between the signal electrode (102) and the ground electrode (101), thereby changing the transmission properties of light in the optical waveguide and achieving efficient electro-optical modulation. The near-zero refractive index electrodes (101, 102) can achieve smaller microwave transmission loss, which is beneficial to improving the electro-optical modulation efficiency.

[0049] Reference Figure 4 As an optional embodiment, the optical waveguide is a ridge optical waveguide, the ridge optical waveguide includes a convex ridge (1033) and a first side wing (1031) and a second side wing (1032) located on both sides of the convex ridge (1033), the ridge optical waveguide is arranged on the upper surface of the substrate (201), the upper surface of the first side wing (1031) is provided with a first buffer layer (2021), the ground electrode (101) is arranged on the first buffer layer (2021), the upper surface of the second side wing (1032) is provided with a second buffer layer (2022), and the signal electrode (102) is arranged on the second buffer layer (2022).

[0050] As a further optional embodiment, the refractive index of the first buffer layer and the second buffer layer are between the refractive index of the ridge optical waveguide and the refractive index of the ground electrode / signal electrode, and the first buffer layer and the second buffer layer are used to achieve group refractive index matching of the ground electrode, the signal electrode and the ridge optical waveguide.

[0051] Specifically, the embodiment of the present invention shows a schematic cross-sectional view perpendicular to the light propagation direction of the fourth electro-optical modulation structure with high modulation efficiency, including a substrate (201), a buffer layer (2021, 2022), a ridge optical waveguide disposed on the substrate, and a ground electrode (101) and a signal electrode (102) disposed on the buffer layer (2021, 2022). The ridge optical waveguide has a limiting effect on light, so that the light is mainly concentrated on the ridge of the ridge optical waveguide for propagation. The buffer layer is made of a material with a refractive index between the refractive index of the optical waveguide and the refractive index of the electrode, and is used to achieve group refractive index matching between the electrode and the optical waveguide. The signal electrode (102) and the ground electrode (101) are made of a near-zero refractive index material. When the distance between the two electrodes is relatively close, the light propagating in the ridge optical waveguide can hardly enter the electrode, which effectively reduces the absorption loss of light, and there is no need to increase the thickness of the buffer layer to avoid excessive absorption loss, thereby effectively improving the electro-optical modulation efficiency. Applying voltage to the near-zero refractive index signal electrode (102) can generate a strong electric field, which can change the electro-optical properties (mainly the refractive index for electro-optical modulation) of the optical waveguide (103) between the signal electrode (102) and the ground electrode (101), thereby changing the transmission properties of light in the optical waveguide and achieving efficient electro-optical modulation. The near-zero refractive index electrodes (101, 102) can achieve a smaller microwave transmission loss, which is conducive to improving the efficiency of electro-optical modulation.

[0052] The structure and working principle of the embodiment of the present invention are described above. It can be recognized that the embodiment of the present invention has a simple structure, and the electrode is made of near-zero refractive index material. The light propagating in the optical waveguide can enter the electrode only when it is perpendicular to the electrode surface, so most of the light in the optical waveguide cannot enter the electrode, which can greatly reduce the absorption loss of the electrode to the light, so that the ground electrode and the signal electrode can be very close to the optical waveguide without increasing the absorption loss of the electrode to the light, and there is no need to increase the thickness of the buffer layer to avoid excessive absorption loss, thereby effectively improving the electro-optical modulation efficiency; the high directional radiation of the near-zero refractive index material can make the electric field concentrate in the direction perpendicular to the surface, provide a strong electric field, and further improve the electro-optical modulation efficiency; in order to meet the impedance matching, the electrode spacing needs to be reduced while the electrode width needs to be reduced, and the near-zero refractive index material can achieve low-loss transmission, so the use of near-zero refractive index material as an electrode can make the microwave loss not too large when the electrode width is small, further improving the electro-optical modulation efficiency.

[0053] It should be noted that, unless the context clearly requires otherwise, the words "comprise", "include" and similar words throughout the specification and claims should be understood to mean inclusive, rather than exclusive or complete. That is, "including but not limited to". The terms "coupled" or "connected" generally used here refer to two or more elements that can be directly connected or connected through one or more intermediate elements. In addition, the words "herein", "above", "below" and words of similar meaning, when used in this application, should refer to the entirety of this application rather than a specific part of this application. If the context permits, detailed descriptions using the singular or plural may include the plural or singular, respectively. The word "or" is about a list containing two or more items, and refers to all of the following interpretations of this word: any item in the list, all items in the list, and all combinations of items in the list.

[0054] The above is only a preferred embodiment of the present invention. The present invention is not limited to the above implementation. As long as the technical effect of the present invention is achieved by the same means, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of protection of the present invention. Within the scope of protection of the present invention, its technical scheme and / or implementation method may have various modifications and changes.

Claims

1. An electro-optic modulation structure with high modulation efficiency, characterized in that: It includes a ground electrode, a signal electrode, an optical waveguide and a substrate, wherein: The ground electrode, the signal electrode and the optical waveguide are all arranged on the substrate, the optical waveguide is located between the ground electrode and the signal electrode, the electrode materials of the ground electrode and the signal electrode are both near-zero refractive index electrode materials, and the ground electrode and the signal electrode are used to generate an electric field to act on the optical waveguide, so that the electro-optical characteristics of the optical waveguide are changed.

2. The electro-optic modulation structure with high modulation efficiency according to claim 1, characterized in that: The optical waveguide is a ridge-shaped optical waveguide, comprising a convex ridge and a first side wing and a second side wing located on both sides of the convex ridge. The ridge-shaped optical waveguide is arranged on the upper surface of the substrate, the ground electrode is arranged on the upper surface of the first side wing, and the signal electrode is arranged on the upper surface of the second side wing.

3. The electro-optic modulation structure with high modulation efficiency according to claim 1, characterized in that: The optical waveguide is a ridge-shaped optical waveguide, which includes a convex ridge and a first side wing and a second side wing located on both sides of the convex ridge. The ground electrode, the signal electrode and the ridge-shaped optical waveguide are all arranged on the upper surface of the substrate, the ground electrode is arranged close to the side of the first side wing, and the signal electrode is arranged close to the side of the second side wing.

4. The electro-optic modulation structure with high modulation efficiency according to claim 1, characterized in that: The optical waveguide is a rectangular optical waveguide. The ground electrode, the signal electrode and the rectangular optical waveguide are all arranged on the upper surface of the substrate. The ground electrode is arranged close to the first side of the rectangular optical waveguide, and the signal electrode is arranged close to the second side of the rectangular optical waveguide.

5. The electro-optic modulation structure with high modulation efficiency according to claim 1, characterized in that: The optical waveguide is a ridge-shaped optical waveguide, comprising a convex ridge and a first side wing and a second side wing located on both sides of the convex ridge. The ridge-shaped optical waveguide is arranged on the upper surface of the substrate, a first buffer layer is arranged on the upper surface of the first side wing, the ground electrode is arranged on the first buffer layer, a second buffer layer is arranged on the upper surface of the second side wing, and the signal electrode is arranged on the second buffer layer.

6. The electro-optic modulation structure with high modulation efficiency according to claim 5, characterized in that: The refractive index of the first buffer layer and the second buffer layer are both between the refractive index of the ridge optical waveguide and the refractive index of the ground electrode / the signal electrode, and the first buffer layer and the second buffer layer are used to achieve group refractive index matching of the ground electrode, the signal electrode and the ridge optical waveguide.

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