Electro-optical modulator and optical chip
Patent Information
- Application Number
- PCT/CN2025/111961
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-04-27
- Filing Date
- 2025-07-31
- Publication Date
- 2026-10-22
Smart Images
Figure CN2025111961_22102026_PF_FP_ABST
Abstract
Description
Electro-optic modulators and optical chips
[0001] Cross-reference to related applications
[0002] This application claims priority to patent application 2025104888208, filed on April 17, 2025, entitled "Electro-optic modulator chip, optical communication device and method for fabricating electro-optic modulator chip", and patent application 2025105457986, filed on April 27, 2025, entitled "Electro-optic modulator chip, optical communication device and method for fabricating electro-optic modulator chip", the entire contents of which are incorporated herein by reference. Technical Field
[0003] This application relates to the field of chips, and more specifically, to an electro-optic modulator and an optical chip. Background Technology
[0004] Electro-optic modulators play a crucial role in modern high-speed communication and numerous optoelectronic applications. They convert electrical signals into optical signals, enabling high-speed, long-distance information transmission and greatly driving the rapid development of optical communication technology. However, with the development of applications such as artificial intelligence, 5G communication, and big data, data transmission volumes are increasing dramatically. Optical communication, as the primary information transmission method, requires higher transmission efficiency. Existing electro-optic modulators are insufficient to meet the future demands of high-speed optical communication for large modulation bandwidths. Summary of the Invention
[0005] In view of this, the purpose of this application is to provide an electro-optic modulator and an optical chip that can improve the modulation bandwidth and reduce the group delay difference of the signal, so as to meet the future demand for large modulation bandwidth in high-speed optical communication.
[0006] In a first aspect, embodiments of this application provide an electro-optic modulator, comprising: an optical modulation unit; the optical modulation unit comprising: a modulation optical path; the optical modulation unit being divided into a plurality of electro-optic modulation regions along the direction of extension of the modulation optical path; the modulation optical path including at least one optical delay line; wherein the optical delay line is disposed between two adjacent electro-optic modulation regions; wherein the refractive index of the optical path material in at least one electro-optic modulation region changes with the modulation voltage in a trend opposite to the refractive index of the optical path material in the other electro-optic modulation regions.
[0007] In the above implementation process, by setting an inverse modulation region and optical delay lines in the electro-optic modulator, the modulation response of low-frequency signals can be reduced. For high-frequency signals, the optical delay lines can induce a phase shift, reducing the phase cancellation effect of modulation on high-frequency signals, thereby reducing attenuation and increasing modulation bandwidth. Furthermore, by setting multiple optical delay lines and multiple inverse modulation regions, the group delay difference introduced by the optical delay lines can be compensated, reducing the group delay difference of the signal and thus minimizing the impact of the optical delay lines on signal transmission, improving signal transmission performance.
[0008] In one embodiment, the modulation optical path includes: a first modulation optical path and a second modulation optical path; the optical delay line includes: a first optical delay line and a second optical delay line; the first modulation optical path includes at least one segment of the first optical delay line; wherein the first optical delay line is disposed between two adjacent electro-optic modulation regions; the second modulation optical path includes at least one segment of the second optical delay line; wherein the second optical delay line is disposed between two adjacent electro-optic modulation regions.
[0009] In one embodiment, the optical modulation unit includes: a first modulation electrode and a second modulation electrode; the first modulation electrode is disposed on the side of the first modulation optical path away from the second modulation optical path; the second modulation electrode is disposed on the side of the second modulation optical path away from the first modulation optical path; wherein the first modulation electrode and the second modulation electrode are configured to receive a pair of differential signals with the same amplitude and a phase difference of φ.
[0010] In the above implementation process, by setting the first modulation electrode and the second modulation electrode to receive a pair of differential signals with the same amplitude and a phase difference of φ, the anti-interference characteristics of differential signals and the phase-opposite design can be fully utilized to improve the signal integrity, modulation efficiency and reliability of the electro-optic modulator.
[0011] In one embodiment, the optical modulation unit includes multiple segments, and the electro-optic modulator chip further includes: a zigzag optical path and a zigzag electrode; the two ends of the zigzag electrode are respectively connected to one end of a first modulation electrode and one end of a second modulation electrode of two adjacent segments; the two ends of the zigzag optical path are respectively connected to one end of the first modulation optical path and one end of the second modulation optical path of two adjacent segments; wherein, the multiple segments are configured to be folded through the zigzag optical path and the zigzag electrode.
[0012] In the above implementation process, when there are many segments of the optical modulation unit, by setting up a tortuous optical path and tortuous electrodes, the multiple optical modulation units can be folded and arranged, which can reduce the size requirements of the electro-optic modulator chip for the multiple optical modulation units. This increases the application scenarios of the electro-optic modulator chip while reducing its size.
[0013] In one embodiment, the electric field direction of the modulation electrode in at least one segment is opposite to the electric field direction of the modulation electrode in other segments; the optical delay line is disposed in an insulating layer between the zigzag electrode and the substrate between two adjacent segments with opposite electric field directions.
[0014] In the above implementation process, by setting the electric field direction of the modulation electrode in at least one segment to be opposite to the electric field direction of the modulation electrode in other segments, the opposite electric field direction can realize the reversal of electrode polarity. In addition, by setting an optical delay line in the insulating layer between the tortuous electrode and the substrate between two adjacent segments with opposite electric field directions, a three-segment superposition effect of high-frequency microwave signal can be formed by the optical delay line and the opposite electric field direction, which further expands the modulator bandwidth and improves the modulation efficiency.
[0015] In one embodiment, the optical modulation unit further includes: a first modulation sub-electrode, a first modulation second sub-electrode, a second modulation first sub-electrode, a second modulation second sub-electrode, a first bridging electrode, and a second bridging electrode; the first modulation first sub-electrode and the second modulation second sub-electrode are located on opposite sides of the first modulation optical path extension direction, and the first modulation second sub-electrode and the second modulation first sub-electrode are located on opposite sides of the second modulation optical path extension direction; the first modulation electrode is connected to the first modulation first sub-electrode and the first modulation second sub-electrode via the first bridging electrode; the second modulation electrode is connected to the second modulation first sub-electrode and the second modulation second sub-electrode via the second bridging electrode; wherein the first modulation electrode and / or the second modulation electrode are configured to modulate the light in the first modulation optical path and / or the second modulation optical path through part or all of the first modulation first sub-electrode, the first modulation second sub-electrode, the second modulation first sub-electrode, and the second modulation second sub-electrode.
[0016] In one embodiment, the optical modulation unit includes multiple modulation sub-units; the modulation sub-units configured with the first modulation sub-electrode, the first modulation sub-electrode, the second modulation sub-electrode, the second modulation sub-electrode, the first bridging electrode, and the second bridging electrode are different from the modulation sub-units configured with the first optical delay line and the second optical delay line.
[0017] In the above implementation process, by setting the modulation sub-units of the first modulation sub-electrode, the first modulation sub-electrode, the second modulation sub-electrode, the second modulation sub-electrode, the first bridging electrode, and the second bridging electrode to be different from the modulation sub-units of the first optical delay line and the second optical delay line, the design and fabrication difficulty of the first optical delay line and the second optical delay line in the modulation sub-unit can be simplified.
[0018] In one embodiment, the length of the first modulation electrode is configured to control the cumulative modulation response of the first modulation electrode corresponding to the electro-optic modulation region; and the length of the second modulation electrode is configured to control the cumulative modulation response of the second modulation electrode corresponding to the electro-optic modulation region.
[0019] In the above implementation process, by setting the length of the first modulation electrode to control the cumulative modulation response of the corresponding electro-optic modulation region of the first modulation electrode, and by setting the length of the second modulation electrode to control the cumulative modulation response of the corresponding electro-optic modulation region of the second modulation electrode, the flexibility and controllability of the modulation response of the electro-optic modulation region can be improved.
[0020] In one embodiment, the optical modulation unit includes a third modulation electrode and a common ground level; the third modulation electrode is disposed between the first modulation optical path and the second modulation optical path; the common ground level is disposed on the side of the first modulation optical path away from the second modulation optical path, and on the side of the second modulation optical path away from the first modulation optical path; wherein, the third modulation electrode is configured to receive a modulation signal, and the common ground level is configured to share a common ground.
[0021] In the above implementation process, by setting a third modulator between the first and second modulation optical paths and a common ground level on both sides of the first and second modulation optical paths, the modulation electrodes, modulation optical paths and other structures in the optoelectronic modulator can share the same potential reference point, avoiding signal distortion caused by ground potential differences, and improving the anti-interference capability and system reliability of the optoelectronic modulator.
[0022] In one embodiment, the first modulation optical path and the second modulation optical path in at least one of the electro-optic modulation regions intersect; the refractive index of the optical path material in the electro-optic modulation region before and after the first modulation optical path and the second modulation optical path intersect changes with the modulation voltage in opposite directions.
[0023] In the above implementation process, by setting at least one intersection of the first and second modulation optical paths in the electro-optic modulation region, the electrode signal can be reverse-driven, thereby forming a "reverse modulation region" in the electro-optic modulation region following the intersection. For low-frequency signals, the modulation response of the low-frequency signal can be reduced through this reverse modulation region. For high-frequency signals, the phase shift of the high-frequency signal can be generated through the reverse modulation region and the optical delay line, reducing the effect of phase cancellation on the modulation of the high-frequency signal, thereby reducing the attenuation of the high-frequency signal and increasing the modulation bandwidth.
[0024] In one embodiment, at least one of the electro-optic modulation regions is modulated based on an applied reverse modulation electric field; wherein the refractive index of the optical path material in the electro-optic modulation region modulated by the reverse modulation electric field changes with the modulation voltage in the opposite direction to the refractive index of the optical path material in the other electro-optic modulation regions.
[0025] In the above implementation process, by applying a reverse modulation electric field in at least one electro-optic modulation region, the sign of the change in the refractive index of the optical waveguide can be reversed, thus forming a "reverse modulation region" in the electro-optic modulation region to which the reverse modulation electric field is applied. For low-frequency signals, the modulation response of the low-frequency signal can be reduced through this reverse modulation region. For high-frequency signals, the phase shift of the high-frequency signal can be generated through the reverse modulation region and the optical delay line, reducing the effect of phase cancellation on the modulation of the high-frequency signal, thereby reducing the attenuation of the high-frequency signal and increasing the modulation bandwidth.
[0026] In one embodiment, the delay of all the optical delay lines is a set multiple of one bit period of the modulation signal corresponding to the optical delay line.
[0027] In the above implementation process, by setting the delay of all optical delay lines to a set multiple of one bit period of the modulation signal corresponding to the optical delay line, a signal of a specific frequency can be made to produce an α phase shift.
[0028] In one embodiment, the electro-optic modulator is made of lithium niobate, silicon, or indium phosphide.
[0029] In the above implementation process, by setting the materials of the optoelectronic modulator to include lithium niobate, silicon, indium phosphide, etc., the optoelectronic modulator can be applied in a variety of scenarios, thus increasing the application scenarios of the optoelectronic modulator.
[0030] Secondly, embodiments of this application also provide an optical chip, including: a laser, a detector, and an electro-optic modulator as described in the first aspect above, or in any possible implementation of the first aspect; the electro-optic modulator is coupled to the laser; wherein the laser is configured to emit an optical signal; the electro-optic modulator is configured to receive and modulate the optical signal; and the detector is configured to detect the modulated optical signal.
[0031] Thirdly, embodiments of this application also provide an optical communication device, including: the electro-optic modulator described in the first aspect above, or in any possible implementation of the first aspect.
[0032] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description
[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0034] Figure 1 is a schematic diagram of an electro-optic modulator including a reverse modulation region provided in an embodiment of this application;
[0035] Figure 2 is a schematic diagram comparing the normalized electro-optic response results of three schemes provided in the embodiments of this application: reverse modulation region + optical delay, reverse modulation region only, and "no optical delay and reverse modulation region".
[0036] Figure 3 is a schematic diagram comparing the unnormalized electro-optic response results of three schemes provided in the embodiments of this application: reverse modulation region + optical delay, reverse modulation region only, and "no optical delay and reverse modulation region".
[0037] Figure 4 is a schematic diagram of a modulator including multiple inverse modulation regions and multiple optical delay lines provided in an embodiment of this application;
[0038] Figure 5 is a schematic diagram of the optical modulation unit provided in an embodiment of this application, which includes two segments;
[0039] Figure 6 is a schematic diagram of the optical modulation unit provided in an embodiment of this application, which includes three segments;
[0040] Figure 7 is a schematic diagram of an optical modulation unit provided in an embodiment of this application, including a third modulation electrode and a common-ground electro-optic modulator;
[0041] Figure 8 is a schematic diagram of an electro-optic modulator with an applied reverse modulation electric field provided in an embodiment of this application.
[0042] Figure descriptions: 200-Optical modulation unit, 211-First modulation electrode, 212-Second modulation electrode, 213-Third modulation electrode, 214-Common ground electrode, 221-First modulation optical path, 222-Second modulation optical path, 2231-First optical delay line, 2232-Second optical delay line, 223-Turbulent optical path, 241-First modulation sub-electrode, 242-First modulation sub-electrode, 243-Second modulation sub-electrode, 244-Second modulation sub-electrode, 245-First bridging electrode, 246-Second bridging electrode, 247-Turbulent electrode, 20-Electro-optic modulation region, 21-Reverse modulation region. Embodiments of the present invention
[0043] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.
[0044] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0045] With the rapid development of technologies such as cloud computing, 5G / 6G communication, and artificial intelligence, global data traffic is growing exponentially, placing higher demands on the transmission rate and bandwidth of optical communication systems. As a core component in optical communication links, the electro-optic modulator is responsible for converting electrical signals into optical signals, and its modulation bandwidth directly determines the system's data transmission capability.
[0046] However, existing optoelectronic modulator technologies often require extremely high driving voltages and significant power consumption to meet the demands of large modulation bandwidth, or they may sacrifice device size, integration, and cost-effectiveness. This irreconcilable contradiction between modulation bandwidth and performance, power consumption, size, and cost has become one of the key bottlenecks restricting the development of cutting-edge technologies such as ultra-high-speed optical communication, optical interconnects, microwave photonics, and quantum information processing.
[0047] In view of this, this application proposes an electro-optic modulator that improves modulation bandwidth while maintaining a low modulation voltage by adding an inverse modulation region and an optical delay line to the optoelectronic modulator, thereby improving modulation efficiency. Furthermore, this electro-optic modulator is applicable to platforms such as silicon, lithium niobate, and indium phosphide, and can be integrated into optical chips to form optical transmitters, meeting the future demand for large modulation bandwidth in high-speed optical communication.
[0048] To facilitate understanding of this embodiment, a detailed description of an electro-optic modulator disclosed in this application embodiment will be provided first.
[0049] Please refer to Figure 1, which is a schematic diagram of an electro-optic modulator provided in an embodiment of this application, including: an optical modulation unit 200.
[0050] The optical modulation unit 200 includes a modulation optical path.
[0051] The optical modulation unit 200 here is divided into multiple electro-optic modulation regions 20 along the direction of the modulation optical path.
[0052] The aforementioned modulation optical path includes at least one optical delay line; wherein the optical delay line is disposed between two adjacent electro-optic modulation regions 20.
[0053] Among them, the trend of the refractive index of the optical path material in at least one electro-optic modulation region 20 changing with the modulation voltage is opposite to the trend of the refractive index of the optical path material in other electro-optic modulation regions 20 changing with the modulation voltage.
[0054] It should be understood that if the trend of the refractive index of the optical path material in a certain electro-optic modulation region 20 changing with the modulation voltage is opposite to the trend of the refractive index of the optical path material in other electro-optic modulation regions 20 changing with the modulation voltage, then the electro-optic modulation region 20 can be identified as the reverse modulation region 21.
[0055] Optionally, there can be one or more reverse modulation regions 21, and the number of reverse modulation regions 21 can be selected according to the actual situation.
[0056] The materials used in the aforementioned modulation optical path are those exhibiting electro-optic effects. Examples include lithium niobate, lithium titanate, barium titanate, or lead zirconate titanate. The specific materials used in this modulation optical path can be selected based on the actual situation.
[0057] An optical delay line is a device that achieves time delay by adjusting the length of the optical signal transmission path or changing the propagation speed of the optical signal. This optical delay line is used to adjust the transmission time of the optical signal.
[0058] Understandably, since the modulation phase change of the inverse modulation region 21 is opposite to that of its electro-optic modulation region 20, it can achieve the effect of modulation phase subtraction for low-frequency signals, thereby reducing the modulation response of low-frequency signals. For high-frequency signals, adding an optical delay line can induce a phase shift in the high-frequency signal, reducing the effect of modulation phase cancellation on the high-frequency signal, and even preventing cancellation at certain frequencies. Therefore, the attenuation of high-frequency signals is smaller, and the modulator bandwidth can be greatly increased.
[0059] For example, as shown in Figure 3, a comparison in Figure 3 shows that by setting optical delay lines and the inverse modulation region 21, the modulator bandwidth can be significantly improved. Figure 2 below shows a comparison of the normalized electro-optical response results of three schemes: inverse modulation region + optical delay, only inverse modulation region, and "no optical delay and inverse modulation region". For a 224G baud rate signal, two optical delay lines with a baud rate of 0.5 were set. By comparison, the scheme in this embodiment has the largest 3dB bandwidth. Figure 3 below calculates the electro-optical response without normalization. Compared with the scheme with only inverse modulation, this scheme has less attenuation of high-frequency components and higher modulation efficiency.
[0060] Understandably, optical delay lines typically introduce group delay differences to signals of different frequencies, thereby affecting signal transmission quality. Group delay difference refers to the difference in group delay between different frequency components of the same signal on the same transmission line.
[0061] In one embodiment, as shown in FIG1, the total electro-optic response of the two electro-optic modulation regions 20 is: .in, The electro-optic response of the forward modulation region. For the electro-optic response of the inverse modulation region 21, For frequency, This is the time delay of the optical delay line.
[0062] when When the imaginary part of the total electro-optic response is not zero, the optical delay line will introduce different phase shifts for signals of different frequencies, increasing the group delay difference.
[0063] By setting multiple optical delay lines and multiple reverse modulation regions, the phase shift introduced by the optical delay lines can be offset, reducing the impact of the optical delay lines on signal transmission.
[0064] In another embodiment, as shown in Figure 4, the total electro-optic response of the three electro-optic modulation regions 20 can be written as: .in, For the electro-optic response of the inverse modulation region 21, The electro-optic response of the forward modulation region. This represents the electro-optic response of the inverse modulation region 21. When = The imaginary part of the total electro-optic response is 0, meaning that the phase shifts generated by the two optical delay lines can cancel each other out, thus not affecting the group delay difference.
[0065] In the above implementation process, by setting an inverse modulation region 21 and an optical delay line in the electro-optic modulator, the modulation response of low-frequency signals can be reduced. For high-frequency signals, the optical delay line can induce a phase shift in the high-frequency signal, reducing the phase cancellation effect of modulation on the high-frequency signal, thereby reducing the attenuation of the high-frequency signal and increasing the modulation bandwidth. In addition, by setting multiple optical delay lines and multiple inverse modulation regions 21, the group delay difference introduced by the optical delay line can be compensated, reducing the group delay difference of the signal, thereby reducing the impact of the optical delay line on signal transmission and improving the signal transmission effect.
[0066] In one possible implementation, as shown in Figure 4, the modulation optical path includes: a first modulation optical path 221 and a second modulation optical path 222; the optical delay line includes: a first optical delay line 2231 and a second optical delay line 2232.
[0067] The first modulation optical path 221 here includes at least one first optical delay line 2231; the second modulation optical path 222 includes at least one second optical delay line 2232.
[0068] The first optical delay line 2231 is disposed between two adjacent electro-optic modulation regions 20, and the second optical delay line 2232 is disposed between two adjacent electro-optic modulation regions 20. The first optical delay line 2231 and the second optical delay line 2232 can be used to adjust the transmission time of the optical signal.
[0069] In one possible implementation, the optical modulation unit 200 includes a first modulation electrode 211 and a second modulation electrode 212.
[0070] The first modulation electrode 211 is disposed on the side of the first modulation optical path 221 away from the second modulation optical path 222; the second modulation electrode 212 is disposed on the side of the second modulation optical path 222 away from the first modulation optical path 221.
[0071] The first modulation electrode 211 and the second modulation electrode 212 are configured to receive a pair of differential signals with the same amplitude and a phase difference of φ.
[0072] Understandably, the out-of-phase characteristic of differential signals causes external noise to generate interference of the same amplitude on both modulation electrodes, which is automatically canceled out during difference calculation, ensuring signal integrity. Additionally, voltage causes a change in the waveguide refractive index, resulting in a phase shift in the optical wave. When the phase difference between the two modulation electrodes is π, destructive interference occurs after beam combining, resulting in minimum output light intensity; when the phase difference is 0, constructive interference occurs, resulting in maximum output light intensity. This design optimizes modulation depth and linearity.
[0073] In the above implementation process, by setting the first modulation electrode 211 and the second modulation electrode 212 to receive a pair of differential signals with the same amplitude and a phase difference of φ, the anti-interference characteristics of differential signals and the phase-opposite design can be fully utilized to improve the signal integrity, modulation efficiency and reliability of the electro-optic modulator.
[0074] The first modulation electrode 211 and the second modulation electrode 212 are used to transmit microwave signals, and the modulation optical path is used to transmit optical signals.
[0075] Optionally, the first modulation signal and the second modulation signal can be a pair of differential signals with the same amplitude and a phase difference of φ.
[0076] In one embodiment, the electro-optic modulator further includes a first resistor and a second resistor.
[0077] Here, the first resistor and the second resistor are connected in series between the first modulation electrode 211 and the second modulation electrode 212.
[0078] In one possible implementation, the optical modulation unit 200 may further include multiple segments, and the electro-optic modulator chip may further include a zigzag optical path 223 and a zigzag electrode 247.
[0079] The two ends of the zigzag electrode 247 are respectively connected to one end of the first modulation electrode 211 and one end of the second modulation electrode 212 of two adjacent segments; the two ends of the zigzag optical path 223 are respectively connected to one end of the first modulation optical path 221 and one end of the second modulation optical path 222 of two adjacent segments.
[0080] The multiple segments here are configured by folding through the zigzag optical path 223 and the zigzag electrode 247.
[0081] In one embodiment, the first modulation optical path 221 and the second modulation optical path 222 are optical waveguides, and the tortuous optical path 223 is a tortuous waveguide.
[0082] It should be understood that the shape of the optical modulation unit 200 may differ depending on the number of segments it includes. For example, it may be U-shaped or S-shaped. The shape of the optical modulation unit 200 can be selected according to the actual situation.
[0083] For example, as shown in FIG5, the optical modulation unit 200 may be a structure comprising two segments, namely, a first optical modulation section M1 and a second optical modulation section M2. The first optical modulation section M1 and the second optical modulation section M2 may be connected by a tortuous optical path 223 and a tortuous electrode 247. The lengths of the first optical modulation section M1 and the second optical modulation section M2 may be equal (shown in FIG5) or unequal.
[0084] As shown in Figure 6, the optical modulation unit 200 can be a structure comprising three segments: a first optical modulation section M1, a second optical modulation section M2, and a third optical modulation section M3. The first optical modulation section M1 and the second optical modulation section M2 can be connected via a zigzag optical path 223 and a zigzag electrode 247, and the second optical modulation section M2 and the third optical modulation section M3 can also be connected via a zigzag optical path 223 and a zigzag electrode 247. The lengths of the first optical modulation section M1, the second optical modulation section M2, and the third optical modulation section M3 can be equal (as shown in Figure 6) or unequal.
[0085] The structure of the optical modulation unit 200 described above is merely exemplary, and the optical modulation unit 200 can be any number of folded structural segments. The specific structure of the optical modulation unit 200 can be adjusted according to actual circumstances.
[0086] It should be understood that when there are many segments in the optical modulation unit 200, by setting up the tortuous optical path 223 and the tortuous electrode 247, the multi-segment optical modulation unit 200 can be folded, which can reduce the size requirements of the multi-segment optical modulation unit 200 on the electro-optic modulation chip, thereby increasing the application scenarios of the electro-optic modulation chip and reducing its size.
[0087] Optionally, the tortuous optical path 223 may include a curved optical path or a zigzag optical path; the tortuous electrode 247 may include a curved electrode or a zigzag electrode. The specific structure of the tortuous optical path 223 and the tortuous electrode 247 can be adjusted according to actual conditions.
[0088] In the above implementation process, when there are many segments in the optical modulation unit 200, by setting up the tortuous optical path 223 and the tortuous electrode 247, the multi-segment optical modulation unit 200 can be folded, which can reduce the size requirements of the multi-segment optical modulation unit 200 on the electro-optic modulator chip, thereby increasing the application scenarios of the electro-optic modulator chip and reducing the size of the electro-optic modulator chip.
[0089] In one possible implementation, the electric field direction of the modulation electrode in at least one segment is opposite to the electric field direction of the modulation electrodes in other segments.
[0090] The modulation electrodes here include a first modulation electrode 211 and / or a second modulation electrode 212. That is, the electric field direction of the first modulation electrode 211 and / or the second modulation electrode 212 in at least one segment is opposite to the electric field direction of the first modulation electrode 211 and / or the second modulation electrode 212 in other segments.
[0091] In one embodiment, the electric field direction of the first modulation electrode 211 and / or the second modulation electrode 212 in the last segment of the optical modulation unit 200 is opposite to the electric field direction of the first modulation electrode 211 and / or the second modulation electrode 212 in other segments besides the last segment.
[0092] The optical delay line is set in the insulating layer between the tortuous electrode 247 and the substrate between two adjacent segments with opposite electric field directions.
[0093] The optical delay lines here include a first optical delay line 2231 and a second optical delay line 2232. The first optical delay line 2231 is disposed in an insulating layer between a first zigzag electrode 247 and the substrate, located between two adjacent segments with opposite electric field directions. The second optical delay line 2232 is disposed in an insulating layer between a second zigzag electrode 247 and the substrate, located between two adjacent segments with opposite electric field directions.
[0094] In the above implementation process, by setting the electric field direction of the modulation electrode in at least one segment to be opposite to the electric field direction of the modulation electrode in other segments, and by setting an optical delay line in the insulating layer between the zigzag electrode 247 and the substrate between two adjacent segments with opposite electric field directions, a three-segment superposition effect of high-frequency signal can be formed by the optical delay line and the opposite electric field direction, which further expands the modulator bandwidth and improves the modulation efficiency.
[0095] In one possible implementation, as shown in FIG8, the optical modulation unit 200 further includes: a first modulation sub-electrode 241, a first modulation sub-electrode 242, a second modulation sub-electrode 243, a second modulation sub-electrode 244, a first bridging electrode 245, and a second bridging electrode 246.
[0096] The first modulation sub-electrode 241 and the second modulation sub-electrode 244 are located on both sides of the extension direction of the first modulation optical path 221, and the first modulation sub-electrode 242 and the second modulation sub-electrode 243 are located on both sides of the extension direction of the second modulation optical path 222. The first modulation electrode 211 is connected to the first modulation sub-electrode 241 and the first modulation sub-electrode 242 through the first bridging electrode 245. The second modulation electrode 212 is connected to the second modulation sub-electrode 243 and the second modulation sub-electrode 244 through the second bridging electrode 246.
[0097] The first modulation electrode 211 and / or the second modulation electrode 212 are configured to modulate the light in the first modulation optical path 221 and / or the second modulation optical path 222 by some or all of the first modulation sub-electrode 241, the first modulation sub-electrode 242, the second modulation sub-electrode 243, and the second modulation sub-electrode 244.
[0098] For example, the first modulation electrode 211 and the second modulation electrode 212 are configured to regulate the light in the first modulation optical path 221 via the first modulation sub-electrode 241 and the second modulation sub-electrode 244. The first modulation electrode 211 and the second modulation electrode 212 are configured to regulate the light in the second modulation optical path 222 via the first modulation sub-electrode 242 and the second modulation sub-electrode 243.
[0099] The first modulation sub-electrode 241, the first modulation second sub-electrode 242, the second modulation first sub-electrode 243, the second modulation second sub-electrode 244, the first bridging electrode 245, and the second bridging electrode 246 are made of conductive materials, such as metals or transparent conductive oxides. The specific materials of these materials can be selected based on actual conditions.
[0100] It should be understood that since both metals and transparent conductive oxides have good conductivity, by setting the materials of the first modulation sub-electrode 241, the first modulation sub-electrode 242, the second modulation sub-electrode 243, the second modulation sub-electrode 244, the first bridging electrode 245, and the second bridging electrode 246 to metals or transparent conductive oxides, the conductivity of the first modulation sub-electrode 241, the first modulation sub-electrode 242, the second modulation sub-electrode 243, the second modulation sub-electrode 244, the first bridging electrode 245, and the second bridging electrode 246 can be improved, thereby improving the modulation efficiency of the electro-optic modulator chip.
[0101] In one possible implementation, the optical modulation unit 200 includes multiple modulation sub-units.
[0102] The modulation sub-units provided by the first modulation sub-electrode 241, the first modulation sub-electrode 242, the second modulation sub-electrode 243, the second modulation sub-electrode 244, the first bridging electrode 245, and the second bridging electrode 246 are different from the modulation sub-units provided by the first optical delay line 2231 and the second optical delay line 2232.
[0103] Understandably, among multiple modulation sub-units, only some sub-units may be configured. Therefore, when configuring the optical modulation unit 200, for modulation sub-units with optical delay lines, the first modulation sub-electrode 241, the first modulation sub-electrode 242, the second modulation sub-electrode 243, the second modulation sub-electrode 244, the first bridging electrode 245, and the second bridging electrode 246 are not configured. For modulation sub-units with the first modulation sub-electrode 241, the first modulation sub-electrode 242, the second modulation sub-electrode 243, the second modulation sub-electrode 244, the first bridging electrode 245, and the second bridging electrode 246, the optical delay line is not configured.
[0104] In the above implementation process, by setting the modulation sub-units of the first modulation sub-electrode 241, the first modulation sub-electrode 242, the second modulation sub-electrode 243, the second modulation sub-electrode 244, the first bridging electrode 245, and the second bridging electrode 246 to be different from the modulation sub-units of the first optical delay line 2231 and the second optical delay line 2232, the design and fabrication difficulty of the first optical delay line 2231 and the second optical delay line 2232 in the modulation sub-unit can be simplified.
[0105] In one possible implementation, the length of the first modulation electrode 211 is configured to control the cumulative modulation response of the corresponding electro-optic modulation region 20 of the first modulation electrode 211; the length of the second modulation electrode 212 is configured to control the cumulative modulation response of the corresponding electro-optic modulation region 20 of the second modulation electrode 212.
[0106] Understandably, since the modulation response is the integral of the voltage signal applied to the light wave with respect to length, the modulation response can be changed by changing the length of the modulation electrode.
[0107] In one embodiment, since the modulation unit is divided into multiple electro-optic modulation regions 20, the cumulative modulation response in each electro-optic modulation region 20 can be controlled by the length of the first modulation electrode 211 and / or the second modulation electrode 212 in the electro-optic modulation region 20.
[0108] In the above implementation process, by setting the length of the first modulation electrode 211 to control the cumulative modulation response of the corresponding electro-optic modulation region 20 of the first modulation electrode 211, and by setting the length of the second modulation electrode 212 to control the cumulative modulation response of the corresponding electro-optic modulation region 20 of the second modulation electrode 212, the flexibility and controllability of the modulation response of the electro-optic modulation region 20 can be improved.
[0109] In one possible implementation, as shown in FIG7, the optical modulation unit 200 includes a third modulation electrode 213 and a common ground electrode 214.
[0110] The third modulation electrode 213 is disposed between the first modulation optical path 221 and the second modulation optical path 222; the common ground electrode 214 is disposed on the side of the first modulation optical path 221 away from the second modulation optical path 222, and on the side of the second modulation optical path 222 away from the first modulation optical path 221.
[0111] The third modulation electrode 213 here is configured to receive and transmit the modulation signal.
[0112] The aforementioned common-ground stage 214 refers to the collaborative operation of multiple circuits or modulation electrodes by sharing the same reference ground, thereby ensuring signal integrity, anti-interference capability, and system reliability. This common-ground stage 214 is configured with a common ground. That is, all modulation electrodes, modulation optical paths, etc., share the same potential reference point, avoiding signal distortion caused by ground potential differences.
[0113] Optionally, the optical modulation unit 200 includes a third modulation electrode 213 and two common ground electrodes 214. The number of the third modulation electrode 213 and the common ground electrodes 214 in the optical modulation unit 200 can be adjusted according to actual conditions.
[0114] In the above implementation process, by setting a third modulator between the first modulation optical path 221 and the second modulation optical path 222, and setting a common ground level 214 on both sides of the first modulation optical path 221 and the second modulation optical path 222, the modulation electrodes, modulation optical paths and other structures in the optoelectronic modulator can share the same potential reference point, avoid signal distortion caused by ground potential differences, and improve the anti-interference capability and system reliability of the optoelectronic modulator.
[0115] In one possible implementation, the first modulation optical path 221 and the second modulation optical path 222 in at least one electro-optic modulation region 20 intersect.
[0116] Among them, the refractive index of the optical path material in the electro-optic modulation region 20 before and after the intersection of the first modulation optical path 221 and the second modulation optical path 222 changes with the modulation voltage in opposite ways.
[0117] Understandably, by setting the first modulation optical path 221 and the second modulation optical path 222 to cross, the phase difference and the reverse drive of the electrode signal can be introduced, thereby forming the "reverse modulation region 21" in the electro-optic modulation region 20 after the cross.
[0118] Among them, the trend of the refractive index of the optical path material in the reverse modulation region 21 with the modulation voltage is opposite to the trend of the refractive index of the optical path material in the other electro-optic modulation region 20 with the modulation voltage.
[0119] In the above implementation process, by setting at least one intersection of the first modulation optical path 221 and the second modulation optical path 222 in the electro-optic modulation region 20, the electrode signal can be reversed, thereby forming a "reverse modulation region 21" in the electro-optic modulation region 20 after the intersection. For low-frequency signals, the modulation response of the low-frequency signal can be reduced through the reverse modulation region 21. For high-frequency signals, the phase shift of the high-frequency signal can be generated through the reverse modulation region 21 and the optical delay line, reducing the effect of phase cancellation of the modulation of the high-frequency signal, thereby reducing the attenuation of the high-frequency signal and increasing the modulation bandwidth.
[0120] In one possible implementation, as shown in Figure 8, at least one electro-optic modulation region 20 is modulated based on an applied reverse modulation electric field.
[0121] Among them, the trend of the refractive index of the optical path material in the electro-optic modulation region 20 modulated by the reverse modulation electric field is opposite to the trend of the refractive index of the optical path material in the other electro-optic modulation regions 20.
[0122] Understandably, by applying a reverse modulation electric field to the electro-optic modulation region 20 and actively controlling the direction of the electric field, the sign of the change in the refractive index of the optical waveguide is reversed, thereby constructing an optical response region at the physical level that is opposite to the effect of the previous modulation region, namely "reverse modulation region 21".
[0123] Among them, only the photoelectric modulation region with the applied reverse modulation electric field forms the reverse modulation region 21.
[0124] Optionally, the inverse modulation region 21 in the electro-optic modulator may include one or more, and the number of inverse modulation regions 21 in the electro-optic modulation region 20 can be selected according to the actual situation.
[0125] In the above implementation process, by applying a reverse modulation electric field in at least one electro-optic modulation region 20, the sign of the change in the refractive index of the optical waveguide can be reversed, thereby forming a "reverse modulation region 21" in the electro-optic modulation region 20 with the applied reverse modulation electric field. For low-frequency signals, the modulation response of the low-frequency signal can be reduced by the reverse modulation region 21. For high-frequency signals, the phase shift of the high-frequency signal can be generated by the reverse modulation region 21 and the optical delay line, reducing the effect of phase cancellation of the modulation of the high-frequency signal, thereby reducing the attenuation of the high-frequency signal and increasing the modulation bandwidth.
[0126] In one possible implementation, the delay of all optical delay lines is a set multiple of one bit period of the modulation signal corresponding to the optical delay line.
[0127] All optical delay lines here refer to the sum of optical delay lines in multiple electro-optic modulation regions 20. The delay of the multiple optical delay lines in these multiple electro-optic modulation regions 20 is a set multiple of one bit period of the corresponding modulation signal.
[0128] In one embodiment, the set factor can be between 0.5 and 1.5.
[0129] Understandably, since the optical delay lines include a first optical delay line 2231 and a second optical delay line 2232, and the modulation electrodes include a first modulation electrode 211 and a second modulation electrode 212, the delay of all first optical delay lines 2231 is a first predetermined multiple of one bit period of the modulation signal received by the corresponding first modulation electrode 211. The delay of all second optical delay lines 2232 is a second predetermined multiple of one bit period of the modulation signal received by the corresponding second modulation electrode 212.
[0130] Optionally, the first set multiple and the second set multiple can be the same or different, and the first set multiple and the second set multiple can be selected according to the actual situation.
[0131] The first set multiplier can be between 0.5 and 1.5, and the second set multiplier can also be between 0.5 and 1.5.
[0132] In the above implementation process, by setting the delay of all optical delay lines to a set multiple of one bit period of the modulation signal corresponding to the optical delay line, a signal of a specific frequency can be made to produce an α phase shift.
[0133] In one possible implementation, the electro-optic modulator is made of materials including lithium niobate, silicon, and indium phosphide.
[0134] Lithium niobate exhibits excellent electro-optic effects; by applying an external electric field, the refractive index of a lithium niobate optical waveguide can be rapidly changed, thereby achieving efficient optical signal modulation. Furthermore, the large refractive index difference between the core and cladding of lithium niobate optical waveguides results in strong signal confinement and low bending loss. This helps reduce signal loss during transmission and improve device performance.
[0135] Silicon is the cornerstone of the semiconductor industry, boasting extremely mature, standardized, and large-scale complementary metal-oxide-semiconductor (CMOS) manufacturing processes and a vast ecosystem. It offers advantages such as low manufacturing costs and high integration.
[0136] Indium phosphide and its alloys possess high absorption coefficients, high responsivity, and high-speed response characteristics, making them a primary material for manufacturing high-performance photodetectors. Furthermore, the operating wavelength of indium phosphide naturally covers the low-loss window of optical fiber communication, making it suitable as a core light source and receiver device for long-distance, high-speed optical communication systems.
[0137] In the above implementation process, by setting the materials of the optoelectronic modulator to include lithium niobate, silicon, indium phosphide, etc., the optoelectronic modulator can be applied in a variety of scenarios, thus increasing the application scenarios of the optoelectronic modulator.
[0138] Furthermore, this application also provides an optical chip, including a laser, a detector, and the electro-optic modulator described in the above embodiments. The electro-optic modulator is coupled to the laser.
[0139] The laser here is configured to emit optical signals; the electro-optic modulator is configured to receive and modulate optical signals; and the detector is configured to detect the modulated optical signals.
[0140] This application also provides an optical communication device, including: the electro-optic modulator chip in the above embodiments.
[0141] The electro-optic modulator in this embodiment can be prepared by the electro-optic modulator preparation method described in the following embodiment.
[0142] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0143] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. An electro-optic modulator, characterized in that, include: Optical modulation unit; The optical modulation unit includes: a modulation optical path; The optical modulation unit is divided into multiple electro-optic modulation regions along the direction of the modulation optical path; The modulation optical path includes at least one optical delay line; wherein the optical delay line is disposed between two adjacent electro-optic modulation regions; In this case, the refractive index of the optical path material in at least one of the electro-optic modulation regions changes with the modulation voltage in a trend opposite to that of the refractive index of the optical path material in the other electro-optic modulation regions.
2. The electro-optic modulator according to claim 1, characterized in that, The modulation optical path includes: a first modulation optical path and a second modulation optical path; The optical delay line includes: a first optical delay line and a second optical delay line; The first modulation optical path includes at least one first optical delay line; wherein the first optical delay line is disposed between two adjacent electro-optic modulation regions; The second modulation optical path includes at least one second optical delay line; wherein the second optical delay line is disposed between two adjacent electro-optic modulation regions.
3. The electro-optic modulator according to claim 2, characterized in that, The optical modulation unit includes: a first modulation electrode and a second modulation electrode; The first modulation electrode is disposed on the side of the first modulation optical path that is away from the second modulation optical path; The second modulation electrode is disposed on the side of the second modulation optical path away from the first modulation optical path; The first modulation electrode and the second modulation electrode are configured to receive a pair of differential signals with the same amplitude and a phase difference of φ.
4. The electro-optic modulator according to claim 3, characterized in that, in, The length of the first modulation electrode is configured to control the cumulative modulation response of the corresponding electro-optic modulation region of the first modulation electrode; The length of the second modulation electrode is configured to control the cumulative modulation response of the corresponding electro-optic modulation region of the second modulation electrode.
5. The electro-optic modulator according to claim 2, characterized in that, The optical modulation unit includes a third modulation electrode and a common ground electrode; The third modulation electrode is disposed between the first modulation optical path and the second modulation optical path; The common ground level is located on the side of the first modulation optical path away from the second modulation optical path, and on the side of the second modulation optical path away from the first modulation optical path; The third modulation electrode is configured to receive modulation signals, and the common ground level is configured to share a common ground.
6. The electro-optic modulator according to claim 2, characterized in that, in, At least one of the first modulation optical paths and the second modulation optical path in the electro-optic modulation region intersects; The refractive index of the optical path material in the electro-optic modulation region before and after the first modulation optical path and the second modulation optical path intersects shows opposite trends with the modulation voltage.
7. The electro-optic modulator according to claim 1, characterized in that, At least one of the electro-optic modulation regions is modulated based on an applied reverse modulation electric field; The refractive index of the optical path material in the electro-optic modulation region modulated by the reverse modulation electric field changes with the modulation voltage in the opposite direction to the refractive index of the optical path material in the other electro-optic modulation regions.
8. The electro-optic modulator according to any one of claims 1-7, characterized in that, The delay of all optical delay lines is a set multiple of one bit period of the modulation signal corresponding to the optical delay line.
9. The electro-optic modulator according to any one of claims 1-7, characterized in that, The materials used in the electro-optic modulator include lithium niobate, silicon, and indium phosphide.
10. An optical chip, characterized in that, include: Laser, detector, and electro-optic modulator as described in any one of claims 1-9; The electro-optic modulator is coupled to the laser; The laser is configured to emit an optical signal; the electro-optic modulator is configured to receive and modulate the optical signal; and the detector is configured to detect the modulated optical signal.