Electro-optical modulator combining slow light waveguide and capacitive load type traveling wave

Abstract

The invention provides an electro-optical modulator combining a slow light waveguide and a capacitive load type traveling wave. The electro-optical modulator comprises the slow light waveguide, a capacitive load type traveling wave electrode, a multi-mode interferometer, a mixed single-mode waveguide, a micro-ring structure and a micro-ring upper phase adjusting electrode. Capacitive load type traveling wave electrodes are arranged between and on the side edges of a pair of slow light waveguides which are arranged in parallel, the two ends of the slow light waveguides are connected to one end of a multimode interferometer through mixed single-mode waveguides respectively, the other end of the multimode interferometer is provided with two ports, one port is used for being connected with a micro-ring structure, and the other port is used for being connected with a micro-ring structure. The other port is used as the input end or the output end of the electro-optical modulator, and the two sides of the micro-ring structure are provided with micro-ring upper phase adjusting electrodes. The group refractive index and the working bandwidth of light can be regulated and controlled by adjusting the geometric parameters of the slow light waveguide, and low dispersion and high group refractive index can be realized in a wide optical bandwidth range; through a sectional capacitance load type slow wave electrode structure, the regulation and control of the microwave refractive index are realized, and the electro-optical modulation bandwidth is improved.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technologies, and in particular, to an electro-optic modulator that combines a slow light waveguide and a capacitively loaded traveling wave. More particularly, it relates to a microring-assisted electro-optic modulator that combines a phase-shifted Bragg grating waveguide and a capacitively loaded traveling wave electrode. Background Art

[0002] In recent years, with the advent of the big data and cloud computing era, and the rapid development of fields such as artificial intelligence technologies and Internet technologies represented by ChatGPT, the global data traffic has shown an explosive growth, driving a sharp increase in the demand for computing power. However, the rapid growth of optical power consumption has become a bottleneck restricting the development of the industry, and there is an urgent need to improve the high-speed and low-power optical interconnection capabilities. Silicon photonics technology, with its advantages of low power consumption, high-speed data transmission capabilities, low-cost mass production, miniaturization and integration characteristics, and excellent compatibility, has become one of the key technologies to solve this problem and has received extensive attention.

[0003] In optical communication technologies, an electro-optic modulator converts a high-speed electrical signal to be transmitted into a high-speed optical signal through the electro-optic effect, and uses an optical fiber as the transmission medium to achieve low-loss and crosstalk-free data transmission. As an important unit for realizing electro-optic conversion and information processing, the electro-optic modulator is a core device in the entire optical communication system. An electro-optic modulator with large bandwidth, low power consumption, and low half-wave voltage characteristics can significantly improve the overall performance of a silicon photonics chip, effectively meet the increasing computing power requirements, and provide guarantee for the stable operation of a high-speed optical communication system.

[0004] From the perspective of device structure, the electro-optic modulator can adopt different design schemes, including Mach-Zehnder interferometers, Michelson interferometers, microring resonators, microdisk resonators, and photonic crystals. Among them, Mach-Zehnder interferometers and Michelson interferometers belong to interferometric modulators, while microring resonators, microdisk resonators, and photonic crystals belong to resonant modulators. Interferometric modulators can generally achieve a relatively high modulation rate and have good performance in terms of process stability and thermal stability. However, their relatively large size is not conducive to large-scale integration. In contrast, resonant modulators have a smaller size, but their process stability and temperature stability are poor, and they are easily affected by the external environment. Therefore, a dedicated temperature control system is required for feedback control. In addition, resonant modulators have a strong dependence on wavelength and it is difficult to work efficiently within a wide spectral range.

[0005] The bandwidth performance of a Mach-Zehnder Modulator (MZM) is mainly determined by its electrode structure. Specifically, the electrode structure of an MZM can be divided into two categories: lumped electrodes and traveling-wave electrodes. In lumped electrodes, the applied radio-frequency signal is usually assumed to be uniformly distributed in time and space, that is, at all positions and moments of the electrode, the amplitude and phase of the radio-frequency signal are the same. In traveling-wave electrodes, considering the time-varying characteristics of the electromagnetic wave propagation on the electrode, the amplitude and phase of the radio-frequency signal will vary with different positions and times on the electrode, thus affecting the performance of the electro-optic modulator. This structural design enables the traveling-wave electrode to provide better modulation performance at higher frequencies, meeting the requirements of high-speed communication and higher bandwidth.

[0006] Currently, most electro-optic modulators are based on the thin-film lithium niobate platform. However, the electro-optic coefficient of lithium niobate material is small, resulting in a large footprint of the modulator, and the trade-off between voltage and bandwidth limits the further improvement of the modulator performance. These problems restrict the wide application of the lithium niobate platform in the field of high-performance electro-optic modulators. Barium titanate, as an emerging electro-optic thin-film material, has an electro-optic coefficient significantly superior to that of lithium niobate, and its low birefringence difference makes it an ideal choice for realizing high-performance integrated electro-optic modulators. The excellent electro-optic characteristics of barium titanate material show great application potential in the field of electro-optic modulators, and it is expected to become the basic platform for the next generation of high-performance electro-optic devices, promoting the development of optical communication technology towards higher speed and lower power consumption. Summary of the Invention

[0007] Aiming at the defects in the prior art, the purpose of the present invention is to provide an electro-optic modulator combining a slow light waveguide and a capacitive load traveling-wave.

[0008] An electro-optic modulator combining a slow light waveguide and a capacitive load traveling-wave according to the present invention includes: a slow light waveguide, a capacitive load traveling-wave electrode, a multimode interferometer, a hybrid single-mode waveguide, a micro-ring structure, and a phase adjustment electrode on the micro-ring;

[0009] A capacitive load traveling-wave electrode is arranged between and on the sides of a pair of parallel slow light waveguides. Both ends of the slow light waveguide are respectively connected to one end of the multimode interferometer through the hybrid single-mode waveguide. The other end of the multimode interferometer is provided with two ports, one port is used to connect the micro-ring structure, and the other port serves as the input end or output end of the electro-optic modulator. Phase adjustment electrodes on the micro-ring are arranged on both sides of the micro-ring structure.

[0010] Preferably, the slow light waveguide, the capacitive load traveling-wave electrode, the multimode interferometer, the hybrid single-mode waveguide, the micro-ring structure, and the phase adjustment electrode on the micro-ring are arranged on the same side of the thin-film barium titanate layer;

[0011] On the other side of the thin film barium titanate layer, a silicon oxide layer is provided, and the silicon oxide layer is provided on the substrate silicon layer.

[0012] Preferably, the slow light waveguide includes: an upper cladding and a periodic fishbone waveguide array structure;

[0013] The periodic fishbone waveguide array structure is coated with an upper cladding on the outside, and both ends of the periodic fishbone waveguide array structure are connected to a hybrid single-mode waveguide. The periodic fishbone waveguide array structure includes: a tooth-like structure and a first straight waveguide;

[0014] Tooth-like structures are provided on both sides of the first straight waveguide.

[0015] Preferably, the micro-ring structure includes: two semi-circular bent waveguides and a second straight waveguide;

[0016] One end of the second straight waveguide is respectively connected to one end of a semi-circular bent waveguide, and the other end of the semi-circular bent waveguide is connected to the multimode interferometer.

[0017] Preferably, the capacitive load traveling-wave electrode includes: a strip electrode and a double-layer T-shaped structure array;

[0018] The double-layer T-shaped structure array is periodically arranged side by side on one side or both sides of the strip electrode.

[0019] Preferably, each sub-period of the periodic fishbone waveguide array structure is composed of a first straight waveguide with tooth-like structures provided on both sides and a phase shifter waveguide connected thereto.

[0020] Preferably, the thickness of the thin film barium titanate layer is 300 nm, the refractive index of the thin film barium titanate layer is 2.38, a 150-nm-thick amorphous silicon thin film is deposited on the thin film barium titanate layer, the refractive index of the amorphous silicon thin film is 3.49, and the amorphous silicon thin film is etched into a slow light waveguide and a hybrid single-mode waveguide;

[0021] The thickness of the silicon oxide layer is 4.7 μm, and the refractive index is 1.44.

[0022] Preferably, the upper cladding is air, and the refractive index is 1.

[0023] Preferably, micro-ring upper phase adjustment electrodes are arranged in parallel on both sides of the second straight waveguide.

[0024] Preferably, a tapered waveguide with a width of 1 - 1.1 μm is used for connection at the connection between the multimode interferometer and the hybrid single-mode waveguide.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. By selecting slow light waveguides with different geometric parameters, the present application can effectively regulate the group refractive index and operating bandwidth of light, achieving low dispersion and high group refractive index within a wide optical bandwidth range;

[0027] 2. By adopting a segmented capacitive load type slow wave electrode structure, the present application can achieve the regulation of the microwave refractive index, thereby weakening the influence of the mismatch between the electro-optic velocity and impedance, and significantly improving the electro-optic modulation bandwidth;

[0028] 3. The introduction of the micro-ring structure enables the modulator to select a specific wavelength for modulation, thereby improving the modulation efficiency;

[0029] 4. Under a 400μm long modulation arm, the 3dB electro-optic bandwidth simulated by the present application can exceed 100GHz, meeting the requirements of high-speed optical communication. Brief Description of the Drawings

[0030] By reading the following detailed description of the non-limiting embodiments with reference to the accompanying drawings, other features, objectives, and advantages of the present invention will become more apparent:

[0031] Figure 1 It is a schematic structural diagram of the electro-optic modulator of the present application;

[0032] Figure 2 It is a partial structural diagram of the slow light waveguide and the capacitive load type traveling wave electrode;

[0033] Figure 3 It is the energy band diagram of the slow light waveguide;

[0034] Figure 4 It is the light transmission spectrum line of the slow light waveguide;

[0035] Figure 5 It is the characteristic impedance, microwave refractive index, loss diagram of the capacitive load type traveling wave electrode, and the corresponding electro-optic response bandwidth diagram of the modulator;

[0036] Figure 6 It is the simulated modulation transmission spectrum line;

[0037] As shown in the figure:

[0038] Detailed Embodiments

[0039] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those of ordinary skill in the art can make several changes and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0040] Embodiment 1

[0041] This embodiment provides a novel electro-optic modulator structure. This electro-optic modulator is based on a barium titanate-insulated silicon oxide platform. Based on the traditional Mach-Zehnder modulator, it is designed by combining a slow light waveguide 1 and a microring structure 7, aiming to enhance the resonance effect of light in the waveguide, thereby improving the modulation efficiency. At the same time, in this embodiment, by introducing a capacitive load traveling wave electrode 2, the electro-optic modulation bandwidth is increased to meet the growing demand for high-speed communication.

[0042] This embodiment includes: a microring structure 7, in which the coupling region is composed of a Mach-Zehnder modulator structure. The Mach-Zehnder modulator structure includes: a pair of parallel slow light waveguides 1, three capacitive load traveling wave electrodes 2 respectively arranged in the middle and outside of the slow light waveguide 1, and both ends of the pair of slow light waveguides 1 are respectively connected to the corresponding multimode interferometers 3.

[0043] The slow light waveguide 1 includes: an upper cladding, a first straight waveguide 102, tooth-shaped structures 101 distributed on both sides of the first straight waveguide 102, and a phase shifter waveguide 103 connecting the first straight waveguide 102.

[0044] The capacitive load traveling wave electrode 2 includes: a strip electrode and an array of double-layer T-shaped structures 201 arranged side by side and periodically on at least one side of the strip electrode.

[0045] One end of the multimode interferometer 3 is respectively connected to one end of a pair of slow light waveguides 1 through two hybrid single-mode waveguides 6, and the other end is provided with two ports, one of which is used as the input or output port of the microring structure 7, and the other port is used as the input end 4 or output end 5 of the entire structure.

[0046] The microring structure 7 includes: two semicircular bent waveguides, which are respectively connected to one port of the multimode interferometer 3, and the other ports of the two semicircular bent waveguides are connected through a second straight waveguide. Strip electrodes are arranged on both sides of the second straight waveguide and are used as phase adjustment electrodes.

[0047] Specifically, as Figure 1 shown, it includes: a slow light waveguide 1, a capacitive load traveling wave electrode 2, a multimode interferometer 3, a hybrid single-mode waveguide 6, a microring structure 7, and a phase adjustment electrode 8 on the microring; capacitive load traveling wave electrodes 2 are arranged between and on the sides of a pair of parallel slow light waveguides 1, both ends of the slow light waveguide 1 are respectively connected to one end of the multimode interferometer 3 through the hybrid single-mode waveguides 6, the other end of the multimode interferometer 3 is provided with two ports, one port is used to connect the microring structure 7, and the other port is used as the input end 4 or output end 5 of the electro-optic modulator, and phase adjustment electrodes 8 on the microring are arranged on both sides of the microring structure 7. The connection between the multimode interferometer 3 and the hybrid single-mode waveguide 6 is made by a tapered waveguide with a width of 1 - 1.1 μm.

[0048] The microring structure 7 includes: two semicircular bent waveguides and a second straight waveguide; both ends of the second straight waveguide are respectively connected to one end of a semicircular bent waveguide, and the other end of the semicircular bent waveguide is connected to the multimode interferometer 3. On both sides of the second straight waveguide, microring upper phase adjustment electrodes 8 are arranged in parallel.

[0049] The slow light waveguide 1, the capacitive load type traveling wave electrode 2, the multimode interferometer 3, the hybrid single mode waveguide 6, the microring structure 7 and the microring upper phase adjustment electrode 8 are arranged on the same side of the barium titanate thin film layer 9; on the other side of the barium titanate thin film layer 9, a silicon oxide layer 10 is arranged, and the silicon oxide layer 10 is arranged on the substrate silicon layer 11. The thickness of the barium titanate thin film layer 9 is 300 nm, the refractive index of the barium titanate thin film layer 9 is 2.38, a 150 nm thick amorphous silicon thin film is deposited on the barium titanate thin film layer 9, the refractive index of the amorphous silicon thin film is 3.49, and the amorphous silicon thin film is etched into the slow light waveguide 1 and the hybrid single mode waveguide 6; the thickness of the silicon oxide layer 10 is 4.7 um, and the refractive index is 1.44.

[0050] As Figure 2 As shown, the slow light waveguide 1 includes: an upper cladding and a periodic fishbone waveguide array structure; the periodic fishbone waveguide array structure is coated with an upper cladding on the outside, and the upper cladding is air with a refractive index of 1. Both ends of the periodic fishbone waveguide array structure are connected to the hybrid single mode waveguide 6, and the periodic fishbone waveguide array structure includes: a tooth-shaped structure 101, a first straight waveguide 102 and a phase shifter waveguide 103. The tooth-shaped structure 101 is arranged on both sides of the first straight waveguide 102, and the first straight waveguide 102 is connected to the phase shifter waveguide 103. The capacitive load type traveling wave electrode 2 includes: a strip electrode and a double-layer T-shaped structure array 201; the double-layer T-shaped structure array 201 is arranged periodically side by side on one side or both sides of the strip electrode.

[0051] Embodiment 2

[0052] Embodiment 2 is a preferred example of Embodiment 1.

[0053] As Figure 1-2 As shown, this embodiment includes: a capacitive load type traveling wave electrode 2 and a pair of parallel slow light waveguides 1 located thereon, wherein: multimode interferometers 3 are respectively arranged at both ends of the slow light waveguide 1.

[0054] The slow light waveguide 1 includes: an upper cladding, and a periodic fishbone waveguide array structure arranged between the hybrid single mode waveguides 6 at both ends, wherein: each sub-period of the periodic fishbone waveguide array structure is composed of a first straight waveguide 102 with tooth-shaped structures 101 arranged on both sides connected to a phase shifter waveguide 103.

[0055] Two waveguides with different widths are set to have the same length l, different widths w1 and w2, and the length of the phase shifter waveguide remains constant. As Figure 4As shown, the transmission spectrum is calculated using the transfer matrix method, and the maximum group refractive index obtained is 6.3.

[0056] The slow light waveguide 1 realizes the function of regulating the group refractive index of light, and at the same time can reduce the modulator length, achieve a multiple increase in the modulation efficiency, and the shortening of the modulator length reduces the microwave loss.

[0057] The capacitive load type traveling wave electrode 2 includes: a plurality of strip electrodes arranged in parallel and a double-layer T-shaped structure array arranged side by side on the strip electrodes, as Figure 5 shown. As the frequency of the radio frequency signal increases, the characteristic impedance of the electrode and the effective refractive index of the radio frequency signal first rapidly decrease and then tend to be stable; while the transmission loss continues to increase. According to the above characteristic data, it can be calculated that the electro-optic bandwidth (3dB) of this structure exceeds 100GHz. Through the finite element simulation method, by adjusting parameters such as the period and horizontal length of the T-shaped structure, the microwave refractive index (index>3) is regulated to match the group refractive index of light, realizing the electro-optic velocity matching and improving the modulation bandwidth.

[0058] The multimode interferometer 3 is of the 2×2 type. Two ports at one end of the multimode interferometer 3 are respectively connected to different slow light waveguides 1 through the hybrid single-mode waveguides 6. One of the ports at the other end is used as the input end 4 or the output end 5, and the other port is used as the input port or the output port of the micro-ring structure 7.

[0059] The micro-ring structure 7 includes: two semi-circular arc waveguides and a second straight waveguide connecting the two semi-circular arc waveguides. One ends of the two semi-circular arc waveguides are respectively used as the input port and the output port and are connected to the two multimode interferometers 3.

[0060] The phase adjustment electrode 8 on the micro-ring includes: strip electrodes arranged in parallel on both sides of the second straight waveguide in the micro-ring structure 7, as Figure 6 shown. By adjusting the voltage of the phase adjustment electrode 8 on the micro-ring, different wavelengths can be selected for modulation, and the modulation depth exceeds 20dB.

[0061] This embodiment relates to a method for implementing the above electro-optic modulator. The electro-optic modulator is realized by depositing and processing silicon on a barium titanate insulating silicon oxide platform, specifically including:

[0062] 1) Set the thickness of the thin film barium titanate layer 9 on the top of the barium titanate insulating silicon oxide platform to be 300nm, the refractive index to be 2.38, the thickness of the silicon oxide layer 10 to be 4.7um, the refractive index to be 1.44, the upper cladding to be air with a refractive index of 1, and deposit a 150nm thick amorphous silicon thin film with a refractive index of 3.49 on the thin film barium titanate layer 9; the width of the conventional hybrid single-mode waveguide 6 is set to 1μm to support the propagation of the TE mode.

[0063] 2) The slow light waveguide 1 is formed by etching a 150-nm-thick amorphous silicon thin film. The period P of a section of the periodic fishbone waveguide array structure is 310 nm. The widths of two groups of waveguides with different widths are 800 nm and 550 nm respectively, and the lengths are both 155 nm. The length of the phase shifter waveguide is 160 nm, and the total length of the slow light waveguide 1 is 400 μm.

[0064] 3) The capacitive load traveling wave electrodes 2 are placed on both sides of the same plane of the 150-nm-thick slow light waveguide 1. The distance between the capacitive load traveling wave electrodes 2 is 5 μm. The T-shaped period of the double-layer T-shaped structure array 201 is 50 μm. The side length at the connection with the strip electrode is 5 μm. The horizontal length of the T-shaped is 45 μm, and the width of the T-shaped is 2 μm.

[0065] The rectangular multimode interference region of the multimode interferometer 3 is 27 μm long and 6 μm wide, and is connected to the hybrid single-mode waveguide 6 by a tapered waveguide with a width ranging from 1.1 μm to 1 μm.

[0066] For the electro-optic modulator, the relationship between its wave vector and normalized frequency is calculated by a finite element simulation software. As Figure 3 shown, there is a 10-nm-wide photonic bandgap near the wavelength of 1550 nm. For the transmission spectrum line of the slow light waveguide 1, as Figure 4 shown, there is a transmission spectrum with a width of about 10 nm at 1550 nm. A large group refractive index is obtained in this transmission window. where λ is the central wavelength, L is the length of one long period of the slow light waveguide 1, and Δλ is the bandwidth of the transmission peak. Substituting the data to calculate n g = 6.3, and a large group refractive index is obtained. Its modulation efficiency V π L calculation formula is where V π is the half-wave voltage of the modulator, L is the modulation arm length, λ is the working wavelength, g is the electrode gap, σ is the overlap factor of the electric field and the optical field, n g is the group refractive index of light, n is the material refractive index of the barium titanate thin film layer 9, and γ BTO is the effective electro-optic coefficient of the barium titanate thin film layer 9. Therefore, the introduction of the slow light effect increases n g , effectively reduces V π L, and greatly improves the modulation efficiency.

[0067] For the capacitive load traveling wave electrodes 2, the relationships between its characteristic impedance, microwave refractive index and loss and frequency are calculated by a finite element simulation software, and finally the electro-optic response curve is obtained, as Figure 5As shown, the use of the slow light waveguide 1 can effectively reduce the length of the waveguide, thereby effectively reducing the microwave signal loss. At the same time, the use of the capacitive load type traveling wave electrode 2 can weaken the influence of the speed mismatch between the electrical signal and the optical signal, thereby greatly increasing the electro-optic bandwidth. The simulated predicted bandwidth can exceed 100 GHz.

[0068] The propagation spectrum of the micro-ring structure 7 is calculated by the transfer function method, as Figure 6 shown. By adjusting the voltage on the phase electrode 8 on the micro-ring, wavelength selection modulation is achieved, thereby optimizing the extinction ratio to be maintained above 20 dB. At the same time, the modulation efficiency can be further increased through the resonance effect of the micro-ring structure 7.

[0069] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present application.

[0070] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. An electro-optic modulator combining a slow light waveguide and a capacitively loaded traveling wave, characterized in that Comprising: Slow optical waveguide (1), capacitively loaded traveling-wave electrode (2), multimode interferometer (3), hybrid single-mode waveguide (6), micro-ring structure (7), and phase adjustment electrode on the micro-ring (8); Between a pair of parallel slow optical waveguides (1) and on the sides thereof, a capacitively loaded traveling-wave electrode (2) is arranged in parallel. Both ends of the slow optical waveguide (1) are respectively connected to one end of the multimode interferometer (3) through the hybrid single-mode waveguide (6). The other end of the multimode interferometer (3) is provided with two ports, one port is used to connect the micro-ring structure (7), and the other port serves as the input end (4) or output end (5) of the electro-optic modulator. On both sides of the micro-ring structure (7), phase adjustment electrodes on the micro-ring (8) are arranged.

2. The electro-optic modulator combining a slow light waveguide and a capacitive load type traveling wave according to claim 1, wherein: The slow optical waveguide (1), capacitively loaded traveling-wave electrode (2), multimode interferometer (3), hybrid single-mode waveguide (6), micro-ring structure (7), and phase adjustment electrode on the micro-ring (8) are arranged on the same side of the thin film barium titanate layer (9); On the other side of the thin film barium titanate layer (9), a silicon oxide layer (10) is arranged, and the silicon oxide layer (10) is arranged on the silicon substrate layer (11).

3. The electro-optic modulator combining a slow light waveguide and a capacitive load type traveling wave according to claim 1, characterized in that, The slow optical waveguide (1) includes: an upper cladding and a periodic fishbone-shaped waveguide array structure; The periodic fishbone-shaped waveguide array structure is coated with an upper cladding on the outside. Both ends of the periodic fishbone-shaped waveguide array structure are connected to the hybrid single-mode waveguide (6). The periodic fishbone-shaped waveguide array structure includes: a tooth-shaped structure (101) and a first straight waveguide (102); Tooth-shaped structures (101) are arranged on both sides of the first straight waveguide (102).

4. The electro-optic modulator combining a slow light waveguide and a capacitive load type traveling wave according to claim 1, characterized in that, The micro-ring structure (7) includes: two semi-circular bent waveguides and a second straight waveguide; Both ends of the second straight waveguide are respectively connected to one end of a semi-circular bent waveguide, and the other end of the semi-circular bent waveguide is connected to the multimode interferometer (3).

5. The electro-optic modulator combining a slow light waveguide and a capacitive load type traveling wave according to claim 1, characterized in that, The capacitively loaded traveling-wave electrode (2) includes: a strip electrode and a double-layer T-shaped structure array (201); Double-layer T-shaped structure arrays (201) are arranged side by side periodically on one side or both sides of the strip electrode.

6. The electro-optic modulator combining a slow light waveguide and a capacitive load type traveling wave according to claim 3, characterized in that: Each sub-period of the periodic fishbone-shaped waveguide array structure is composed of a first straight waveguide (102) with tooth-shaped structures (101) arranged on both sides and connected to a phase shifter waveguide (103).

7. The electro-optic modulator combining a slow light waveguide and a capacitive load type traveling wave according to claim 2, characterized in that: The thickness of the thin film barium titanate layer (9) is 300 nm, the refractive index of the thin film barium titanate layer (9) is 2.

38. A 150-nm-thick amorphous silicon thin film is deposited on the thin film barium titanate layer (9), and the refractive index of the amorphous silicon thin film is 3.

49. The amorphous silicon thin film is etched into the slow optical waveguide (1) and the hybrid single-mode waveguide (6); The thickness of the silicon oxide layer (10) is 4.7 μm, and the refractive index is 1.

44.

8. The electro-optic modulator combining a slow light waveguide and a capacitive load type traveling wave according to claim 3, characterized in that: The upper cladding is air, and the refractive index is 1.

9. The electro-optic modulator combining a slow light waveguide and a capacitive load type traveling wave according to claim 4, characterized in that: Phase adjustment electrodes on the micro-ring (8) are arranged in parallel on both sides of the second straight waveguide.

10. The electro-optic modulator combining a slow light waveguide and a capacitive load traveling wave according to claim 1, characterized in that: At the connection between the multimode interferometer (3) and the hybrid single-mode waveguide (6), a tapered waveguide with a width of 1 - 1.1 μm is used for connection.

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