Thin-film lithium niobate electro-optical modulator and method based on electromagnetically-like induced transparency effect

Abstract

The invention provides a thin-film lithium niobate electro-optical modulator and method based on an electromagnetically-like induced transparency effect, and relates to the technical field of optical fiber communication. The thin film lithium niobate electro-optical modulator comprises a thin film lithium niobate substrate; the optical waveguide structure is formed on the thin-film lithium niobate substrate and comprises a direct light waveguide and an annular resonant cavity waveguide which are coupled with each other, and the annular resonant cavity waveguide is configured to be capable of supporting at least one first optical mode and at least one second optical mode which are different in optical mode; the first optical mode and the second optical mode can generate coherent coupling and interference, so that a transmission spectrum of the straight light waveguide forms an electromagnetically-induced transparent transmission peak in the micro-ring resonant cavity and generates high-dispersion optical response; the traveling wave electrode system is arranged on the annular resonant cavity waveguide and is used for applying a modulation electric field to the annular resonant cavity waveguide; and the direct current bias device is connected with the traveling wave electrode system and is used for superposing the direct current bias voltage and the radio frequency modulation voltage and then applying the superposed voltage to the traveling wave electrode system.

Description

Technical Field

[0001] This disclosure relates to the field of optical fiber communication technology, and more specifically, to a thin-film lithium niobate electro-optic modulator and method based on an electromagnetically induced transparency effect. Background Technology

[0002] High-efficiency electro-optic modulators are the core of modern optical communication networks. While traditional electro-optic modulators based on Mach-Zehnder interferometers offer stable performance, they typically require waveguide lengths on the order of centimeters to achieve sufficient phase modulation depth, hindering the miniaturization and high-density integration of photonic chips. Microring resonator modulators utilize the resonance enhancement effect to achieve effective modulation at the micrometer scale; however, the performance of traditional single-ring modulators is limited by the inherent characteristics of the Lorentz-type resonance peak, such as the need for critical coupling for high extinction ratios. This often leads to an irreconcilable contradiction between modulation efficiency and bandwidth.

[0003] In atomic physics, the electromagnetically induced transparency (EIT) effect can produce an extremely narrow transparent window against a broad absorption background, accompanied by steep dispersion. In integrated photonics, an "EIT-like" optical response can be simulated by designing multimode interference in coupled microrings. Combining this response with its sharp dispersion characteristics with thin-film lithium niobate, a highly electro-optic material, holds promise for achieving high-efficiency modulation. Summary of the Invention

[0004] In view of this, the present disclosure provides a thin-film lithium niobate electro-optic modulator and method based on an electromagnetically induced transparency effect, in order to at least partially solve at least one of the above-mentioned technical problems.

[0005] One aspect of this disclosure provides a thin-film lithium niobate electro-optic modulator based on an electromagnetically induced transparency-like effect, comprising: a thin-film lithium niobate substrate; an optical waveguide structure formed on the thin-film lithium niobate substrate, the optical waveguide structure including a straight waveguide and a ring resonant cavity waveguide coupled to each other, wherein the ring resonant cavity waveguide is configured to support at least one first optical mode and at least one second optical mode with different optical modes, the first optical mode and the second optical mode being coherently coupled and interfering, so that the transmission spectrum of the straight waveguide forms an electromagnetically induced transparency transmission peak in the micro-ring resonant cavity and generates a high-dispersion optical response; a traveling-wave electrode system disposed on the ring resonant cavity waveguide for applying a modulation electric field to the ring resonant cavity waveguide; and a DC biaser connected to the traveling-wave electrode system for applying a DC bias voltage and an RF modulation voltage superimposed on the traveling-wave electrode system; wherein the electrical signal applied to the traveling-wave electrode system can change the effective refractive index of the ring resonant cavity waveguide through the electro-optic effect of the thin-film lithium niobate, so as to shift the spectral position of the electromagnetically induced transparency transmission peak, thereby achieving intensity modulation of the output optical signal of the straight waveguide.

[0006] According to embodiments of this disclosure, a first optical mode characterizes a bright mode that can be directly coupled to a straight waveguide, and a second optical mode characterizes a dark mode that cannot be directly coupled to a straight waveguide but can be coupled to the bright mode through near-field interaction.

[0007] According to embodiments of this disclosure, the structure of the ring resonant cavity waveguide is configured as one of a racetrack-shaped, elliptical, or C-shaped structure, and the structure of the ring resonant cavity waveguide is configured as an asymmetric structure to enhance the coupling between the bright mode and the dark mode.

[0008] According to embodiments of this disclosure, the traveling wave electrode system is configured as a coplanar waveguide electrode structure, including a central signal electrode and two ground electrodes disposed on both sides of the central signal electrode. The electrode orientation of the coplanar waveguide electrode structure matches the geometry of the ring resonant cavity waveguide to achieve phase velocity matching between the radio frequency signal and the optical signal.

[0009] According to embodiments of this disclosure, a traveling wave electrode system is disposed above the region in the ring resonant cavity waveguide where the light field intensities of at least one first optical mode and at least one second optical mode overlap most, in order to maximize electro-optic interaction.

[0010] According to embodiments of this disclosure, a thin dielectric layer for isolation is provided between the traveling wave electrode system and the ring resonant cavity waveguide.

[0011] According to embodiments of this disclosure, the DC bias includes a capacitor, an inductor, a DC port, an RF port, and a combined output port.

[0012] According to embodiments of this disclosure, capacitors and inductors together form a filter network to filter out high-frequency noise and ensure signal stability; the input terminal of the DC port is connected to an external adjustable DC voltage source to provide a DC bias voltage; the input terminal of the RF port is connected to an external RF signal source to provide an RF modulation signal; and the combined output port is electrically connected to the center signal electrode of the traveling wave electrode system for tuning the operating point.

[0013] Another aspect of this disclosure provides a thin-film lithium niobate electro-optic modulation method based on an electromagnetically induced transparency-like effect, comprising: inputting a continuous laser into a straight optical waveguide, wherein the wavelength of the continuous laser is located near an electromagnetically induced transparency-like window; adjusting the DC bias voltage of a DC biaser so that the operating point of the thin-film lithium niobate electro-optic modulator is located at the steep edge of the electromagnetically induced transparency-like window; inputting an radio frequency modulation signal into the radio frequency port of the DC biaser; applying the DC bias voltage and the radio frequency modulation voltage to the center signal electrode of a traveling wave electrode system using the DC biaser, thereby causing a spectral shift in the electromagnetically induced transparency-like window through the electro-optic effect of the thin-film lithium niobate, causing the output light intensity at a fixed wavelength of the continuous laser to change with the radio frequency signal, thereby realizing the modulation and encoding of an electrical signal into an optical signal.

[0014] Another aspect of this disclosure provides an optical communication system, comprising: a light source module for providing a continuous optical carrier; a thin-film lithium niobate electro-optic modulator for generating a modulated optical signal carrying data information; and a driving circuit module for providing a radio frequency modulation signal and a DC bias voltage to drive the thin-film lithium niobate electro-optic modulator to achieve optical signal modulation.

[0015] Compared with the prior art, the thin-film lithium niobate electro-optic modulator and method based on electromagnetically induced transparency effect provided in this disclosure have at least the following beneficial effects:

[0016] (1) The thin-film lithium niobate electro-optic modulator and method based on electromagnetically induced transparency effect provided in this disclosure enhances electro-optic interaction by utilizing electromagnetically induced transparency effect on the thin-film lithium niobate platform. A small change in refractive index can trigger a huge change in light intensity, thereby achieving electro-optic modulation with high modulation efficiency, low driving voltage and high bandwidth under the size of micro-devices.

[0017] (2) The thin-film lithium niobate electro-optic modulator and method based on electromagnetically induced transparency effect provided in this disclosure has a modulation function with only one DC bias, and the operating point control circuit is simple. There is no need to configure an independent drive source and feedback loop for the operating point of a conventional modulator, which reduces the complexity and cost of the peripheral circuit. By adjusting the DC bias of the DC bias and the radio frequency signal, the operating point can be accurately set and adjusted. It is easy to compensate for the drift caused by the change of refractive index with temperature. The system response speed reaches the nanosecond or even picosecond level, which is more suitable for high-speed communication.

[0018] (3) The thin-film lithium niobate electro-optic modulator and method based on electromagnetically induced transparency effect provided in this disclosure synergistically utilize the “slow light” effect of EIT and the strong electro-optic effect of thin-film lithium niobate to achieve high extinction ratio and high efficiency modulation in a micro-ring with a micrometer size. At the same time, by optimizing the traveling wave electrode, the high bandwidth potential is retained, which is conducive to large-scale integration. Attached Figure Description

[0019] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0020] Figure 1 A schematic diagram of a thin-film lithium niobate electro-optic modulator based on an electromagnetically induced transparency effect according to an embodiment of the present disclosure is shown.

[0021] Figure label:

[0022] 1-Straight optical waveguide; 2-Ring resonant cavity waveguide; 3-Traveling wave electrode system; 4-DC biaser. Detailed Implementation

[0023] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0025] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0026] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0027] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0028] Figure 1 A schematic diagram of a thin-film lithium niobate electro-optic modulator based on an electromagnetically induced transparency effect according to an embodiment of the present disclosure is shown.

[0029] like Figure 1 As shown, the thin-film lithium niobate electro-optic modulator based on the electromagnetically induced transparency effect in this embodiment may include, for example, a thin-film lithium niobate substrate, an optical waveguide structure, a traveling wave electrode system 3, and a DC biaser (Bias-T) 4.

[0030] The optical waveguide structure is formed on a thin-film lithium niobate substrate and includes a straight optical waveguide 1 and a ring resonant cavity waveguide 2 (i.e., a micro-ring resonator waveguide) that are coupled to each other.

[0031] The straight waveguide 1 is used to couple external continuous laser light into the chip and to couple the modulated optical signal out.

[0032] The ring resonant waveguide 2 is spatially adjacent to the straight waveguide 1 and is laterally coupled. The ring resonant waveguide 2 is configured to support at least one first optical mode and at least one second optical mode with different optical modes. The first and second optical modes can coherently couple and interfere, so that the transmission spectrum of the straight waveguide 1 forms an electromagnetically induced transparent transmission peak in the micro-ring resonant cavity and generates a high-dispersion optical response.

[0033] The traveling wave electrode system 3 is disposed on the ring resonant cavity waveguide 2 and is used to apply a modulation electric field to the ring resonant cavity waveguide 2.

[0034] The DC bias 4 is connected to the traveling wave electrode system 3 and is used to apply the DC bias voltage and the radio frequency modulation voltage superimposed on the traveling wave electrode system 3. The electrical signal applied to the traveling wave electrode system 3 can change the effective refractive index of the ring resonant cavity waveguide 2 through the electro-optic effect of thin film lithium niobate, so as to shift the spectral position of the electromagnetically induced transparent transmission peak, thereby realizing the intensity modulation of the output optical signal of the straight optical waveguide 1.

[0035] In this embodiment, the straight waveguide 1, the ring resonant cavity waveguide 2, the traveling wave electrode system 3, and the DC biaser 4 are sequentially connected to form a complete electro-optic path.

[0036] According to embodiments of this disclosure, a first optical mode characterizes a bright mode that can be directly coupled to a straight waveguide, and a second optical mode characterizes a dark mode that cannot be directly coupled to a straight waveguide but can be coupled to the bright mode through near-field interaction.

[0037] For example, in this embodiment, the first optical mode is a bright mode directly coupled to the direct waveguide 1, which can be directly coupled to the incident light, but its Q value is low and its loss is high, corresponding to the excited state in the EIT atomic system. The second optical mode is a dark mode indirectly excited by the bright mode, which cannot be directly coupled to the incident light, but can be coupled to the bright mode through near-field interaction. Its Q value is high and its loss is extremely low, corresponding to the metastable state in the EIT atomic system. When these two modes are frequency-simple and coupled, they will interfere destructively, opening an extremely narrow transparent window in the originally broad absorption or reflection spectrum, accompanied by strong dispersion.

[0038] According to embodiments of this disclosure, the structure of the ring resonant cavity waveguide 2 is configured as one of a racetrack-shaped, elliptical, or C-shaped structure, and the structure of the ring resonant cavity waveguide is configured as an asymmetric structure to enhance the coupling between the bright mode and the dark mode.

[0039] For example, in the embodiments of this disclosure, the structure of the ring resonant cavity waveguide 2 can be designed in various shapes, including but not limited to racetrack-shaped, elliptical, or C-shaped, etc. Its structural asymmetry is used to support and couple bright modes and dark modes, such as a "bright mode" with a low quality factor and a "dark mode" with a high quality factor, thereby generating an electromagnetically induced transparency-like phenomenon.

[0040] According to an embodiment of the present disclosure, the traveling wave electrode system 3 is configured as a coplanar waveguide electrode structure (GSG), including a central signal electrode S and two ground electrodes G disposed on both sides of the central signal electrode. The electrode orientation of the coplanar waveguide electrode structure matches the geometry of the ring resonant cavity waveguide 2 to achieve phase velocity matching between the radio frequency signal and the optical signal.

[0041] For example, in this embodiment of the present disclosure, the orientation and size of the traveling wave electrode system 3 are optimized so that its characteristic impedance matches the external driving circuit and the phase velocity matching of the light wave and microwave is achieved as much as possible to support high-speed modulation. The center signal electrode S is located at the center of the ring resonant cavity waveguide 2 and receives the driving signal from the combined output port of the DC bias 4.

[0042] According to embodiments of this disclosure, the traveling wave electrode system 3 is disposed above the region in the ring resonant cavity waveguide 2 where the light field intensity of at least one first optical mode and at least one second optical mode overlaps the most, in order to maximize electro-optic interaction.

[0043] According to embodiments of this disclosure, a thin dielectric layer for isolation is provided between the traveling wave electrode system 3 and the ring resonant cavity waveguide 2 to reduce optical loss.

[0044] For example, in the embodiments of this disclosure, silicon dioxide (SiO2) or silicon nitride (Si3N4) can be used as a thin dielectric layer to act as an insulator, and its thickness can be designed according to specific needs to ensure a balance between electro-optical efficiency and optical loss.

[0045] According to embodiments of this disclosure, the DC bias 4 may include, for example, a capacitor, an inductor, a DC port, an RF port, and a combined output port.

[0046] The capacitor and inductor together form a filter network to filter out high-frequency noise and ensure signal stability.

[0047] The input of this DC port is connected to an external high-precision adjustable DC voltage source to provide DC bias voltage.

[0048] The input of this RF port is connected to an external high-speed RF signal source to provide RF modulation signals.

[0049] The combined output port is electrically connected to the center signal electrode of the traveling wave electrode system for tuning the operating point.

[0050] In this embodiment, the DC biaser 4 applies a DC bias voltage and an RF modulation voltage to the center signal electrode of the traveling wave electrode system. This causes a slight spectral shift in the electromagnetically induced transparent transmission window (EIT) due to the strong electro-optic effect of lithium niobate, resulting in a change in the output light intensity at the wavelength of the input continuous light. Simultaneously, the slow-light effect caused by the "EIT-like" effect further improves the electro-optic modulation efficiency. Specifically:

[0051] A DC bias voltage is applied to the lithium niobate material in the ring resonator waveguide 2 region through the central signal electrode. The electro-optic effect of lithium niobate causes its refractive index to change linearly with the DC bias, resulting in a translation of the entire EIT-like spectrum on the wavelength axis. The value of the DC bias voltage is finely adjusted, and when the optical power change is most sensitive, that is, at the midpoint of the linear region on the steep edge of the transmission curve, the adjustment is stopped. At this time, the operating point of the system has been precisely set. The DC bias plays the role of static wavelength tuning and operating point locking. The rapid change of the radio frequency modulation signal causes the total voltage to fluctuate rapidly, which causes a rapid and small change in the refractive index of the ring resonator waveguide 2 through the electro-optic effect. This causes the center wavelength of the EIT-like transparent peak to swing rapidly and slightly. Since the operating point is set on the steep edge, the small wavelength swing of the transparent peak will cause a large and rapid change in the output light intensity at a fixed wavelength. The intensity of the output light is precisely encoded by the radio frequency signal, thereby realizing efficient and high-speed intensity modulation from electrical signal to optical signal.

[0052] In this embodiment, a DC bias 4 is used instead of a traditional thermal tuner, simplifying the driving circuit and reducing the complexity and cost of the peripheral circuit. By adjusting the DC bias and the radio frequency signal, the operating point can be flexibly and precisely set and fine-tuned. Furthermore, the "slow light" effect caused by the "EIT-like" effect effectively prolongs the residence time of light in the modulation region, greatly improving the interaction between light and matter. Sufficient phase accumulation or modulation depth can be achieved without a long interaction length, which is beneficial for realizing an ultra-compact and efficient electro-optic modulator at the micrometer scale.

[0053] This disclosure also provides a thin-film lithium niobate electro-optic modulation method based on an electromagnetically induced transparency effect, including operations S1 to S4.

[0054] In operation S1, a continuous laser is input into the straight waveguide, wherein the wavelength of the continuous laser is located near the electromagnetically induced transparent window.

[0055] In operation S2, the DC bias voltage of the DC biaser is adjusted so that the operating point of the thin-film lithium niobate electro-optic modulator is located at the steep edge of the electromagnetically induced transparent window.

[0056] In operation S3, the RF modulation signal is input to the RF port of the DC bias.

[0057] In operation S4, a DC bias voltage and an RF modulation voltage are applied to the center signal electrode of the traveling wave electrode system using a DC biaser. The electro-optic effect of thin-film lithium niobate causes a spectral shift in the electromagnetically induced transparent window, causing the output light intensity at a fixed wavelength of the continuous laser to change with the RF signal, thereby realizing the modulation and coding of the electrical signal to the optical signal.

[0058] For example, in an embodiment of this disclosure, a continuous laser beam is first input into a straight waveguide, the wavelength of which corresponds to a wavelength near an electromagnetically induced transparent window.

[0059] Then, by adjusting the voltage output of the DC bias source, the static operating point of the electro-optic modulation chip is set at the steep edge of the electromagnetically induced transparent window.

[0060] Next, the radio frequency data signal is applied as a modulation voltage to the radio frequency signal source.

[0061] Finally, the DC bias voltage and the RF modulation voltage are applied to the center signal electrode of the traveling wave electrode system through the DC biaser. The electro-optic effect causes a slight shift in the spectrum of the electromagnetically induced transparent transmission window, resulting in a change in the output light intensity at the wavelength of the input continuous light, thereby efficiently encoding the modulation voltage signal onto the output light.

[0062] This disclosure also provides an optical communication system, which may include, for example, a light source module, a thin-film lithium niobate electro-optic modulator, and a driving circuit module.

[0063] The light source module is used to provide a continuous optical carrier.

[0064] Thin-film lithium niobate electro-optic modulators are used to generate modulated optical signals that carry data information.

[0065] The driving circuit module is used to provide radio frequency modulation signals and DC bias voltage to drive the thin-film lithium niobate electro-optic modulator to achieve optical signal modulation.

[0066] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions. Those skilled in the art will understand that the features described in the various embodiments of the present disclosure can be combined and / or combined in various ways, even if such combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments of this disclosure may be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0067] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A thin-film lithium niobate electro-optic modulator based on an electromagnetically induced transparency effect, characterized in that, include: Thin-film lithium niobate substrate; An optical waveguide structure is formed on the thin-film lithium niobate substrate. The optical waveguide structure includes a straight optical waveguide and a ring resonant cavity waveguide coupled to each other. The ring resonant cavity waveguide is configured to support at least one first optical mode and at least one second optical mode with different optical modes. The first optical mode and the second optical mode can coherently couple and interfere, so that the transmission spectrum of the straight optical waveguide forms an electromagnetically induced transparent transmission peak in the micro-ring resonant cavity and generates a high-dispersion optical response. A traveling wave electrode system is disposed on the annular resonant cavity waveguide and is used to apply a modulation electric field to the annular resonant cavity waveguide; A DC bias unit, connected to the traveling wave electrode system, is used to apply the superimposed DC bias voltage and the RF modulation voltage to the traveling wave electrode system. The electrical signal applied to the traveling wave electrode system can change the effective refractive index of the ring resonant cavity waveguide through the electro-optic effect of thin-film lithium niobate, thereby shifting the spectral position of the electromagnetically induced transparent transmission peak and thus achieving intensity modulation of the output optical signal of the straight waveguide.

2. The thin-film lithium niobate electro-optic modulator according to claim 1, characterized in that, The first optical mode represents a bright mode that can be directly coupled to the straight waveguide, and the second optical mode represents a dark mode that cannot be directly coupled to the straight waveguide but can be coupled to the bright mode through near-field interaction.

3. The thin-film lithium niobate electro-optic modulator according to claim 2, characterized in that, The ring resonant cavity waveguide is configured as one of a racetrack-shaped, elliptical, or C-shaped structure, and the ring resonant cavity waveguide is configured as an asymmetric structure to enhance the coupling between the bright mode and the dark mode.

4. The thin-film lithium niobate electro-optic modulator according to claim 3, characterized in that, The traveling wave electrode system is configured as a coplanar waveguide electrode structure, including a central signal electrode and two ground electrodes disposed on both sides of the central signal electrode. The electrode orientation of the coplanar waveguide electrode structure matches the geometry of the annular resonant cavity waveguide to achieve phase velocity matching between the radio frequency signal and the optical signal.

5. The thin-film lithium niobate electro-optic modulator according to claim 1, characterized in that, The traveling wave electrode system is positioned above the region in the annular resonant cavity waveguide where the light field intensities of at least one first optical mode and at least one second optical mode overlap most significantly, in order to maximize electro-optic interaction.

6. The thin-film lithium niobate electro-optic modulator according to claim 1, characterized in that, A thin dielectric layer for isolation is provided between the traveling wave electrode system and the annular resonant cavity waveguide.

7. The thin-film lithium niobate electro-optic modulator according to claim 1, characterized in that, The DC biaser includes a capacitor, an inductor, a DC port, an RF port, and a combined output port.

8. The thin-film lithium niobate electro-optic modulator according to claim 7, characterized in that, The capacitor and the inductor together form a filter network, which is used to filter out high-frequency noise and ensure signal stability; The input terminal of the DC port is connected to an external adjustable DC voltage source to provide a DC bias voltage. The input terminal of the radio frequency port is connected to an external radio frequency signal source to provide a radio frequency modulation signal; The merged output port is electrically connected to the center signal electrode of the traveling wave electrode system for tuning the operating point.

9. A thin-film lithium niobate electro-optic modulation method based on an electromagnetically induced transparency effect, applied to the thin-film lithium niobate electro-optic modulator as described in any one of claims 1 to 8, characterized in that, The method includes: A continuous laser is input into the straight waveguide, wherein the wavelength of the continuous laser is located near the electromagnetically induced transparent window; Adjust the DC bias voltage of the DC biaser so that the operating point of the thin-film lithium niobate electro-optic modulator is located at the steep edge of the electromagnetically induced transparent window; The radio frequency modulation signal is input to the radio frequency port of the DC bias; The DC bias voltage and the radio frequency modulation voltage are applied to the center signal electrode of the traveling wave electrode system using the DC biaser. The electro-optic effect of the thin-film lithium niobate causes a slight spectral shift in the electromagnetically induced transparent window, so that the output light intensity at a fixed wavelength of the continuous laser changes with the radio frequency signal, thereby realizing the modulation and encoding of the electrical signal to the optical signal.

10. An optical communication system, characterized in that, include: The light source module is used to provide a continuous optical carrier. A thin-film lithium niobate electro-optic modulator is used to generate a modulated optical signal carrying data information, wherein the thin-film lithium niobate electro-optic modulator is the thin-film lithium niobate electro-optic modulator as described in any one of claims 1 to 8; The driving circuit module is used to provide radio frequency modulation signals and DC bias voltage to drive the thin-film lithium niobate electro-optic modulator to achieve optical signal modulation.

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