A low half-wave voltage lead niobate-lead magnesium niobate-lead titanate electro-optic modulator and a preparation method thereof

Abstract

The application discloses a low half-wave voltage lead niobate-lead magnesium niobate-lead titanate electro-optical modulator and a preparation method thereof. The electro-optical modulator comprises a substrate, an optical waveguide, a silicon dioxide film and a modulation electrode. The substrate is made of lead niobate-lead magnesium niobate-lead titanate single crystal material. The optical waveguide is formed by diffusing metal titanium from the upper surface of the substrate to the inside of the substrate. The silicon dioxide film is arranged on the upper surface of the substrate. The modulation electrode is arranged on the upper surface of the silicon dioxide film. The electric field direction of the modulation electrode is parallel to the core layer of the optical waveguide and perpendicular to the transmission direction of light. The application can effectively reduce the half-wave voltage of the electro-optical device, reduce the size of the device, and the preparation process is simple and easy to realize.

Description

Technical Field

[0001] This invention relates to the fields of optical fiber communication, optical fiber sensing, microwave optical fiber links, and quantum communication, and specifically to a low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator and its preparation method. Background Technology

[0002] Electro-optic modulators are core components of high-speed fiber optic communication networks, inertial navigation systems, and microwave photonics systems. Typically, electro-optic modulators rely on the interaction between light and chip materials—the electro-optic effect—to encode electrical signals into optical signals. However, with the continued rapid growth of global data traffic and the energy consumption issues arising from communication technologies, existing electro-optic modulators currently face limitations in achieving ultra-high capacity, ultra-high speed, ultra-long distance, and low-loss optical transmission.

[0003] Currently, the main device used for high-speed electro-optic modulation is the lithium niobate waveguide electro-optic modulator. However, this traditional bulk LiNbO3 modulator is composed of an optical waveguide with a low refractive index difference. The microwave electrode must be located far from the optical waveguide to minimize absorption loss, thus limiting further reductions in the driving voltage. Furthermore, there is always a trade-off between the device's interaction region length and half-wave voltage; existing bulk LiNbO3 modulators cannot simultaneously achieve low half-wave voltage, ultra-high bandwidth, and small device size.

[0004] To achieve high-performance LiNbO3 electro-optic modulators with wider bandwidth, lower power consumption, and more compact device structures, breakthroughs have been made in the performance of thin-film lithium niobate electro-optic modulators in recent years. Studies have shown that thin-film lithium niobate ridge waveguides with high refractive index differences can improve modulation efficiency and effectively reduce half-wave voltage. Harvard University reported a monolithically integrated thin-film lithium niobate electro-optic modulator that achieves a voltage-length product of 2.8 V·cm and a bandwidth of 45 GHz. However, although the performance of thin-film lithium niobate electro-optic modulators is improved compared to traditional LN modulators, the fabrication of thin-film modulators is very complex, especially the etching process, making it difficult to achieve low cost and meet the application requirements of long-distance fiber optic links. Currently, most commercial LN modulators are still based on titanium diffused or proton exchange waveguides, preventing the widespread application of thin-film lithium niobate electro-optic modulators. Therefore, developing novel high-performance electro-optic crystals and using advanced micro-nano fabrication techniques to fabricate electro-optic modulators with low driving voltages are urgent problems to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator and its fabrication method, so as to overcome the defects of the prior art, effectively reduce the half-wave voltage of the device, reduce the size of the device, and the fabrication process is simple and easy to implement.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator includes a substrate, an optical waveguide, a silicon dioxide thin film, and a modulation electrode;

[0008] The substrate is made of lead indium niobate-lead magnesium niobate-lead titanate single crystal material. The optical waveguide is formed by diffusing metallic titanium from the upper surface of the substrate into the interior of the substrate. The silicon dioxide thin film is disposed on the upper surface of the substrate. The modulation electrode is disposed on the upper surface of the silicon dioxide thin film. The electric field direction of the modulation electrode is parallel to the core layer of the optical waveguide and perpendicular to the light transmission direction.

[0009] Furthermore, the substrate is a trigonal single crystal material of lead indium niobate-lead magnesium niobate-lead titanate, and the thickness of the substrate is 0.1 mm to 1.5 mm.

[0010] Furthermore, the optical waveguide is a straight strip structure or an MZ structure, the width of the optical waveguide is 5μm to 20μm, and the light propagation direction along the optical waveguide is the

[100] direction.

[0011] Furthermore, the thickness of the silicon dioxide film is 0.1 μm to 2 μm.

[0012] Furthermore, the modulation electrode is a thin-film traveling wave electrode made of gold, and the thickness of the modulation electrode is 100nm to 300nm.

[0013] Furthermore, the spacing between the modulation electrode and the optical waveguide is 5μm to 15μm.

[0014] A method for fabricating a low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator includes the following steps:

[0015] Annealing treatment was performed on the substrate prepared using lead indium niobate-lead magnesium niobate-lead titanate single crystal material;

[0016] The annealed substrate is then optically polished.

[0017] Waveguide patterns are designed on a substrate using photolithography.

[0018] Optical waveguides are fabricated using a titanium diffusion process and installed inside a substrate.

[0019] Silicon dioxide thin films are prepared on the surface of a substrate containing optical waveguides using sputtering or PECVD processes.

[0020] The modulation electrode is prepared by evaporation or sputtering and mounted on the surface of a silicon dioxide thin film;

[0021] The substrate with the modulation electrodes installed is polarized using a high-temperature polarization process, and then sliced ​​and polished to obtain the modulator chip.

[0022] The chip is end-to-end coupled and fixed to the optical fiber;

[0023] The assembled and fixed chip is packaged into a housing to complete the fabrication of the electro-optic modulator.

[0024] Furthermore, the annealing temperature for the substrate annealing treatment is 650℃~750℃, and the holding time is 5h~10h.

[0025] Furthermore, when using titanium diffusion process to fabricate optical waveguides, the titanium diffusion temperature is 950℃~1050℃, and the holding time is 10h~15h.

[0026] Furthermore, the substrate with the modulation electrode mounted using a high-temperature polarization process includes:

[0027] The temperature is gradually increased to 110℃~140℃, and a DC voltage of 3 times the coercive field is applied to the substrate with the modulation electrode installed. The DC voltage is kept constant until the temperature cools down to room temperature, and polarization is completed.

[0028] Compared with the prior art, the present invention has the following beneficial technical effects:

[0029] This invention designs a low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator. By using lead indium niobate-lead magnesium niobate-lead titanate crystals with excellent linear electro-optic effects to fabricate a novel electro-optic modulator, the half-wave voltage of the device can be effectively reduced, while the size of the device can be reduced. Moreover, the fabrication process is simple and easy to implement, solving the problems of high driving voltage of traditional LN modulators and difficulty in fabricating thin-film electro-optic modulators mentioned in the background art. Specifically, in this invention, lead indium niobate-lead magnesium niobate-lead titanate single crystal material is used as the chip substrate. It has excellent optical and electro-optic properties, can achieve high transparency, and the polarized crystal exhibits good linear electro-optic effect. Its electro-optic coefficient is tens of times better than that of advanced LN and far higher than that of lithium niobate crystal. At the same time, an optical waveguide structure with a refractive index difference is prepared on the lead indium niobate-lead magnesium niobate-lead titanate substrate through titanium diffusion process, and the modulation electrode is designed on both sides of the optical waveguide so that the electric field direction is parallel to the waveguide core layer and perpendicular to the light transmission direction. The resulting electro-optic modulator can effectively reduce the half-wave voltage and device size of the electro-optic modulator, laying a solid foundation for its application in compact, low-voltage electro-optic modulators. Attached Figure Description

[0030] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0031] Figure 1 This is a front view cross-sectional schematic diagram of the lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator (straight waveguide structure) described in Embodiment 1 of the present invention;

[0032] Figure 2 This is a schematic diagram of the chip cross-sectional structure of the lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator (straight waveguide structure) described in Embodiment 1 of the present invention;

[0033] Figure 3 This is a front cross-sectional view of the lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator (MZ structure) described in Embodiment 3 of the present invention.

[0034] Figure 4 This is a flowchart illustrating the fabrication process of the lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator described in Embodiment 1 of the present invention.

[0035] Figure 5 This is a static EO performance diagram of the lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator described in Embodiment 1 of the present invention.

[0036] In the figure, the input fiber is 1, the modulator chip is 2, the optical waveguide is 3, the modulation electrode is 4, the output fiber is 5, the substrate is 6, and the silicon dioxide thin film is 7. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0039] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0040] Example 1

[0041] This embodiment provides a low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator, such as... Figure 1 and Figure 2 As shown, it includes a substrate 6, an optical waveguide 3, a silicon dioxide thin film 7, and a modulation electrode 4;

[0042] The substrate 6 is made of lead indium niobate-lead magnesium niobate-lead titanate single crystal material (i.e., PIN-PMN-PT single crystal material, the same below). The optical waveguide 3 is formed by diffusing metallic titanium from the upper surface of the substrate 6 into the interior of the substrate 6. The silicon dioxide thin film 7 is disposed on the upper surface of the substrate 6. The modulation electrode 4 is disposed on the upper surface of the silicon dioxide thin film 7 and is located on both sides of the optical waveguide 3. The electric field direction of the modulation electrode 4 is parallel to the core layer of the optical waveguide 3 and perpendicular to the light transmission direction.

[0043] In this first embodiment, the substrate 6 is a trigonal PIN-PMN-PT single crystal material with a thickness of 1 mm.

[0044] In this first embodiment, the optical waveguide 3 is fabricated using a titanium diffusion process, has a straight strip structure, and a waveguide width of 10 μm.

[0045] Preferably, the silicon dioxide thin film 7 is deposited on a PIN-PMN-PT substrate containing an optical waveguide 3 structure by sputtering, and has a thickness of 0.5 μm, which can effectively improve impedance matching and reduce velocity mismatch.

[0046] Preferably, the modulation electrode 4 is a thin-film traveling wave electrode made of gold, and the thickness of the modulation electrode 4 is 200 nm; the spacing between the modulation electrode 4 and the optical waveguide is 5 μm to reduce the absorption loss of the electrode to the waveguide.

[0047] The fabrication process of the low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator provided in this embodiment is as follows: Figure 4 As shown, the specific steps include:

[0048] S1. Select a trigonal PIN-PMN-PT single crystal as the substrate, with a thickness of 1mm;

[0049] S2. Anneal the PIN-PMN-PT substrate to eliminate internal stress. The annealing temperature is 700℃ and the holding time is 10 hours.

[0050] S3. The annealed PIN-PMN-PT substrate is optically polished using grinding and polishing processes.

[0051] S4. A straight-line waveguide structure with a width of 10μm is designed using photolithography.

[0052] S5. Optical waveguide 3 is formed by titanium diffusion process, with diffusion temperature of 1000℃ and heat preservation time of 10h;

[0053] S6. A silicon dioxide thin film 7 with a thickness of 0.5 μm is prepared on a PIN-PMN-PT substrate containing an optical waveguide 3 structure using sputtering or PECVD process;

[0054] S7. The modulation electrode 4 is formed by evaporation or sputtering process;

[0055] S8. The PIN-PMN-PT substrate is polarized using a high-temperature polarization method to improve the transmittance of the crystal. The polarization process is heated to 120°C, and a DC voltage of 3 times the coercive field is applied to the sample. The voltage is maintained until the temperature is slowly cooled to room temperature to obtain the modulator chip.

[0056] S9. Use precision diamond blades to precisely cut the chip, and design suitable fixtures to polish the chip's end face;

[0057] S10. Using a direct coupling docking method with end-face coupling, the two ends of the chip are docked and fixed to the input optical fiber 1 and the output optical fiber 5 respectively.

[0058] S11. Package the assembled chip into a housing to complete the device fabrication and obtain a low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate phase modulator.

[0059] like Figure 5 The figure shows the static EO performance of a lead indium niobate-lead magnesium niobate-lead titanate phase modulator with a straight waveguide structure as described in Embodiment 1. The half-wave voltage V of the lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator with an interaction region length of 9 mm is also shown. π The voltage is 2.3V, from which the compressibility product of the device (V) can be deduced. πThe voltage (·L) is only 2.03 V·cm. This also demonstrates the great potential of electro-optic modulators based on PIN-PMN-PT crystals in the field of miniaturization and low-actuation devices.

[0060] Example 2

[0061] This second embodiment provides another low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator, whose structure is the same as that of the first embodiment, including a substrate 6, an optical waveguide 3, a silicon dioxide thin film 7 and a modulation electrode 4;

[0062] The substrate 6 is made of lead indium niobate-lead magnesium niobate-lead titanate single crystal material. The optical waveguide 3 is formed by diffusing metallic titanium from the upper surface of the substrate 6 into the interior of the substrate 6. The silicon dioxide thin film 7 is disposed on the upper surface of the substrate 6. The modulation electrode 4 is disposed on the upper surface of the silicon dioxide thin film 7 and is located on both sides of the optical waveguide 3. The electric field direction of the modulation electrode 4 is parallel to the core layer of the optical waveguide 3 and perpendicular to the light transmission direction.

[0063] In this second embodiment, the substrate 6 is a trigonal PIN-PMN-PT single crystal material with a thickness of 0.1 mm.

[0064] In this second embodiment, the optical waveguide 3 is fabricated using a titanium diffusion process, has a straight strip structure, and a waveguide width of 20 μm.

[0065] Preferably, the silicon dioxide thin film 7 is deposited on a PIN-PMN-PT substrate containing an optical waveguide 3 structure using a PECVD process, and has a thickness of 2μm, which can effectively improve impedance matching and reduce velocity mismatch.

[0066] Preferably, the modulation electrode 4 is a thin-film traveling wave electrode made of gold, and the thickness of the modulation electrode 4 is 100 nm; the spacing between the modulation electrode 4 and the optical waveguide is 15 μm, and the larger electrode spacing can reduce the absorption loss of the electrode to the waveguide.

[0067] The fabrication process of the low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator provided in this embodiment includes the following steps:

[0068] S1. Select a trigonal PIN-PMN-PT single crystal as the substrate with a thickness of 0.1 mm;

[0069] S2. Anneal the PIN-PMN-PT substrate at a temperature of 650℃ for 5 hours.

[0070] S3. The annealed PIN-PMN-PT substrate is optically polished using grinding and polishing processes.

[0071] S4. A straight-line waveguide structure with a width of 20μm is designed using photolithography technology;

[0072] S5. Optical waveguide 3 is formed by titanium diffusion process, with diffusion temperature of 1050℃ and heat preservation time of 15h;

[0073] S6. A silicon dioxide thin film 7 with a thickness of 2μm is prepared on a PIN-PMN-PT substrate containing an optical waveguide 3 structure by sputtering or PECVD process;

[0074] S7. The modulation electrode 4 is formed by evaporation or sputtering process;

[0075] S8. The PIN-PMN-PT substrate is polarized using a high-temperature polarization method to improve the transmittance of the crystal. The polarization process is heated to 110°C, and a DC voltage of 3 times the coercive field is applied to the sample. The voltage is maintained until the temperature is slowly cooled to room temperature to obtain the modulator chip.

[0076] S9. Use precision diamond blades to precisely cut the chip, and design suitable fixtures to polish the chip's end face;

[0077] S10. Using a direct coupling docking method with end-face coupling, the two ends of the chip are docked and fixed to the input optical fiber 1 and the output optical fiber 5 respectively.

[0078] S11. Package the assembled chip into a housing to complete the device fabrication and obtain a phase modulator based on lead indium niobate-lead magnesium niobate-lead titanate.

[0079] Example 3

[0080] This embodiment three provides a low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate intensity modulator, such as... Figure 3 As shown, it includes a substrate 6, an optical waveguide 3, a silicon dioxide thin film 7, and a modulation electrode 4;

[0081] The substrate 6 is made of lead indium niobate-lead magnesium niobate-lead titanate single crystal material. The optical waveguide 3 is formed by diffusing metallic titanium from the upper surface of the substrate 6 into the interior of the substrate 6, and has an MZ structure. The silicon dioxide thin film 7 is disposed on the upper surface of the substrate 6, and the modulation electrode 4 is disposed on the upper surface of the silicon dioxide thin film 7. The electric field direction of the modulation electrode 4 is parallel to the core layer of the optical waveguide 3 and perpendicular to the light transmission direction.

[0082] In this third embodiment, the substrate 6 is a trigonal PIN-PMN-PT single crystal material with a thickness of 1.5 mm.

[0083] In this third embodiment, the optical waveguide 3 is an MZ structure, consisting of two Y-branch waveguides. The Y-branch is arc-shaped and is fabricated using a titanium diffusion process. The waveguide width is 5 μm.

[0084] In this third embodiment, the silicon dioxide thin film 7 is deposited on a PIN-PMN-PT substrate containing an optical waveguide 3 structure by sputtering or PECVD process, with a thickness of 0.1 μm, which can effectively improve impedance matching and reduce velocity mismatch.

[0085] In this third embodiment, the modulation electrode 4 includes a center electrode and two ground electrodes. The center electrode is located between the branches of the MZ-structured optical waveguide 3, and the ground electrodes are located on the outer sides of the branches of the MZ-structured optical waveguide 3. The modulation electrode 4 is a thin-film traveling wave electrode made of gold, with a thickness of 300 nm; the distance between the modulation electrode and the waveguide is 10 μm.

[0086] The fabrication process of the low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator provided in this embodiment includes the following steps:

[0087] S1. Select a trigonal PIN-PMN-PT single crystal as the substrate, with a thickness of 1.5mm;

[0088] S2. Anneal the PIN-PMN-PT substrate to eliminate internal stress. The annealing temperature is set to 750℃ and the holding time is 8 hours.

[0089] S3. The annealed PIN-PMN-PT substrate is optically polished using grinding and polishing processes.

[0090] S4. The MZ waveguide structure is designed using photolithography. The optical waveguide 3 of the MZ structure includes two Y-branch waveguides. The Y-branch is arc-shaped and the waveguide width is 5μm.

[0091] S5. Optical waveguide 3 is prepared using titanium diffusion process, with a diffusion temperature of 950℃ and a holding time of 12h.

[0092] S6. A silicon dioxide thin film 7 with a thickness of 0.1 μm is prepared on a PIN-PMN-PT substrate containing an optical waveguide 3 structure using sputtering or PECVD process;

[0093] S7. The modulation electrode 4 is formed by evaporation or sputtering process;

[0094] S8. The PIN-PMN-PT substrate is polarized using a high-temperature polarization method to improve the transmittance of the crystal. The polarization process is heated to 140°C, and a DC voltage of 3 times the coercive field is applied to the sample. The voltage is maintained until the temperature is slowly cooled to room temperature to obtain the modulator chip.

[0095] S9. Use precision diamond blades to precisely cut the chip, and design suitable fixtures to polish the chip's end face;

[0096] S10. Using a direct coupling docking method with end-face coupling, the two ends of the chip are docked and fixed to the input optical fiber 1 and the output optical fiber 5 respectively.

[0097] S11. Package the assembled chip into a housing to complete the device fabrication and obtain an intensity modulator based on lead indium niobate-lead magnesium niobate-lead titanate.

[0098] This invention designs a low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator. By using lead indium niobate-lead magnesium niobate-lead titanate crystals with excellent linear electro-optic effects to fabricate a novel electro-optic modulator, the half-wave voltage of the device can be effectively reduced, while the size of the device can be reduced. Moreover, the fabrication process is simple and easy to implement, solving the problems of high driving voltage of traditional LN modulators and difficulty in fabricating thin-film electro-optic modulators mentioned in the background art. Specifically, in this invention, lead indium niobate-lead magnesium niobate-lead titanate single crystal material is used as the chip substrate 6, which has excellent optical and electro-optic properties, can achieve high transparency, and the polarized crystal exhibits good linear electro-optic effect. Its electro-optic coefficient is tens of times better than that of advanced LN and far higher than that of lithium niobate crystal. At the same time, an optical waveguide 3 structure with a refractive index difference is prepared on the lead indium niobate-lead magnesium niobate-lead titanate substrate through diffusion process, and the modulation electrode 4 is designed on both sides of the optical waveguide 3 so that the electric field direction is parallel to the waveguide core layer and perpendicular to the light transmission direction. The resulting electro-optic modulator can effectively reduce the half-wave voltage and device size of the electro-optic modulator, laying a solid foundation for its application in compact, low-voltage electro-optic modulators.

[0099] Furthermore, in other application scenarios, improving the modulation efficiency of the electric field by etching a ridge waveguide structure, or constructing a single-drive push-pull device structure to achieve opposite phase shifts in the two arms, is expected to further reduce the half-wave voltage of the electro-optic modulator.

[0100] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator, characterized in that, It includes a substrate (6), an optical waveguide (3), a silicon dioxide thin film (7), and a modulation electrode (4); The substrate (6) is made of trigonal lead indium niobate-lead magnesium niobate-lead titanate single crystal material. The optical waveguide (3) is formed by diffusing metallic titanium from the upper surface of the substrate (6) into the interior of the substrate (6). The silicon dioxide thin film (7) is disposed on the upper surface of the substrate (6). The modulation electrode (4) is disposed on the upper surface of the silicon dioxide thin film (7). The electric field direction of the modulation electrode (4) is parallel to the core layer of the optical waveguide (3) and perpendicular to the light transmission direction. The light transmission direction along the optical waveguide is the [100] direction.

2. The low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator according to claim 1, characterized in that, The thickness of the substrate (6) is 0.1 mm to 1.5 mm.

3. A low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator according to claim 1, characterized in that, The optical waveguide (3) is a straight strip structure or an MZ structure, and the width of the optical waveguide (3) is 5μm to 20μm.

4. A low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator according to claim 1, characterized in that, The thickness of the silicon dioxide film (7) is 0.1 μm to 2 μm.

5. A low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator according to claim 1, characterized in that, The modulation electrode (4) is a thin-film traveling wave electrode made of gold, and the thickness of the modulation electrode (4) is 100 nm ~ 300 nm.

6. A low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator according to claim 1, characterized in that, The distance between the modulation electrode (4) and the optical waveguide (3) is 5μm to 15μm.

7. A method for fabricating a low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator according to any one of claims 1-6, characterized in that, Includes the following steps: Annealing treatment was performed on the substrate (6) prepared using lead indium niobate-lead magnesium niobate-lead titanate single crystal material; The annealed substrate (6) is optically polished; Waveguide patterns were designed on the substrate (6) using photolithography. An optical waveguide (3) is fabricated using a titanium diffusion process and installed inside a substrate (6); A silicon dioxide thin film (7) is prepared on the surface of a substrate (6) containing an optical waveguide (3) by sputtering or PECVD. The modulation electrode (4) is prepared by evaporation or sputtering and mounted on the upper surface of the silicon dioxide thin film (7); The substrate (6) with the modulation electrode (4) installed is polarized by high temperature polarization process and then sliced ​​and polished to obtain the modulator chip; The chip is end-to-end coupled and fixed to the optical fiber; The assembled and fixed chip is packaged into a housing to complete the fabrication of the electro-optic modulator.

8. A method for fabricating a low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator according to claim 7, characterized in that, The annealing temperature of the substrate (6) is 650℃~750℃, and the holding time is 5h~10h.

9. A method for fabricating a low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator according to claim 7, characterized in that, When the optical waveguide (3) is prepared by titanium diffusion process, the titanium diffusion temperature is 950℃~1050℃ and the heat preservation time is 10 h~15 h.

10. The method for fabricating a low half-wave voltage lead indium niobate-lead magnesium niobate-lead titanate electro-optic modulator according to claim 7, characterized in that, The substrate (6) with the modulation electrode (4) polarized using a high-temperature polarization process includes: The temperature is gradually increased to 110℃~140℃. A DC voltage of 3 times the coercive field is applied to the substrate (6) after the modulation electrode (4) is installed. The DC voltage remains unchanged until the temperature cools down to room temperature, and polarization is completed.

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