Folding electro-optic modulator

Abstract

Provided is a folded electro-optical modulator, comprising: a first main electrode, a first waveguide arm, a second main electrode, a second waveguide arm and a third main electrode arranged in sequence without crossing; and the following structure arranged in a radio frequency modulation region at any even sequence position: a plurality of first sub-electrodes, each connected to one side of the first main electrode close to the second main electrode through a first connecting arm crossing the first waveguide arm insulatively; a plurality of second sub-electrodes, each connected to one side of the second main electrode close to the first main electrode through a second connecting arm crossing the first waveguide arm insulatively; a plurality of third sub-electrodes, each connected to one side of the second main electrode close to the third main electrode through a third connecting arm crossing the second waveguide arm insulatively; and a plurality of fourth sub-electrodes, each connected to one side of the third main electrode close to the second main electrode through a fourth connecting arm crossing the second waveguide arm insulatively. The embodiment scheme of the present disclosure can take into account the performance requirement and size requirement of the device.

Description

Technical Field

[0001] This disclosure relates to the field of optical communication technology, and in particular to a folded electro-optic modulator. Background Technology

[0002] In recent years, with the rapid development of emerging network applications such as the Internet of Things, autonomous driving, telemedicine, and distance education, higher demands have been placed on high-speed, high-capacity communication technologies. Optical communication, due to its large bandwidth, high reliability, low cost, and strong anti-interference capabilities, has achieved rapid development in the field of high-speed, high-capacity communication. How to load high-speed electrical signals onto optical carriers is a core research topic.

[0003] An electro-optic modulator is a type of modulator based on the electro-optic effect of electro-optic materials. The electro-optic effect refers to the phenomenon where, when a voltage is applied to an electro-optic material such as lithium niobate crystal, gallium arsenide crystal, or lithium tantalate crystal, the refractive index of the material changes, thereby altering the characteristics of the light wave passing through it. Utilizing the electro-optic effect, it is possible to modulate parameters such as the phase, amplitude, intensity, and polarization state of an optical signal.

[0004] A Mach-Zehnder modulator is a type of electro-optic modulator that splits an input optical signal into two branches, each branch entering a separate waveguide arm. These waveguide arms are made of electro-optic materials whose refractive index varies with the applied modulation voltage. This change in refractive index causes a phase shift in the branched optical signal; therefore, the combined output signal is an interference signal whose intensity varies with the modulation voltage. In short, by controlling the modulation voltage applied to the two waveguide arms, a Mach-Zehnder modulator can modulate different sidebands. As a device that converts electrical signals into optical signals, the Mach-Zehnder modulator is a common core component in optical interconnects, optical computing, and optical communication systems.

[0005] With the increasing demand for high-speed, high-capacity communication technologies, higher requirements are being placed on the device performance and size of electro-optic modulators. Summary of the Invention

[0006] This disclosure provides a foldable electro-optic modulator to achieve miniaturization of the device while meeting device performance requirements.

[0007] The folded electro-optic modulator provided in this disclosure includes: a first waveguide arm and a second waveguide arm that are folded in shape and do not intersect each other; a first main electrode, a second main electrode, and a third main electrode that are folded in shape and do not intersect each other; the first waveguide arm is located between the first main electrode and the second main electrode; the second waveguide arm is located between the second main electrode and the third main electrode; the first main electrode and the third main electrode are ground electrodes for radio frequency (RF) signals; and the second main electrode is a signal electrode for RF signals; and the following structure is provided in the RF modulation region of any even-numbered position of the folded electro-optic modulator along the transmission direction of the first waveguide arm and the second waveguide arm:

[0008] A plurality of first sub-electrodes, each first sub-electrode being connected to the side of a first main electrode near the second main electrode via a first connecting arm that is insulated from and intersects with the first waveguide arm; a plurality of second sub-electrodes, each second sub-electrode being connected to the side of a second main electrode near the first main electrode via a second connecting arm that is insulated from and intersects with the first waveguide arm; a plurality of third sub-electrodes, each third sub-electrode being connected to the side of a second main electrode near the third main electrode via a third connecting arm that is insulated from and intersects with the second waveguide arm; and a plurality of fourth sub-electrodes, each fourth sub-electrode being connected to the side of a third main electrode near the second main electrode via a fourth connecting arm that is insulated from and intersects with the second waveguide arm.

[0009] In some embodiments, each first sub-electrode and its corresponding first connecting arm form a first T-shaped structure, each second sub-electrode and its corresponding second connecting arm form a second T-shaped structure, and multiple first T-shaped structures and multiple second T-shaped structures are alternately arranged along the extension direction of the radio frequency modulation region, wherein the gap between adjacent first sub-electrodes is smaller than the length of the second sub-electrode, and the gap between adjacent second sub-electrodes is smaller than the length of the first sub-electrode; and each third sub-electrode and its corresponding third connecting arm form a third T-shaped structure, each fourth sub-electrode and its corresponding fourth connecting arm form a fourth T-shaped structure, and multiple third T-shaped structures and multiple fourth T-shaped structures are alternately arranged along the extension direction of the radio frequency modulation region, wherein the gap between adjacent third sub-electrodes is smaller than the length of the fourth sub-electrode, and the gap between adjacent fourth sub-electrodes is smaller than the length of the third sub-electrode.

[0010] In some embodiments, each first sub-electrode and its corresponding first connecting arm form a first L-shaped structure, each second sub-electrode and its corresponding second connecting arm form a second L-shaped structure, and a plurality of first L-shaped structures and a plurality of second L-shaped structures are alternately arranged along the extension direction of the radio frequency modulation region, and the orthographic projections of each first sub-electrode and a second sub-electrode in the extension direction of the radio frequency modulation region overlap; and each third sub-electrode and its corresponding third connecting arm form a third L-shaped structure, each fourth sub-electrode and its corresponding fourth connecting arm form a fourth L-shaped structure, and a plurality of third L-shaped structures and a plurality of fourth L-shaped structures are alternately arranged along the extension direction of the radio frequency modulation region, and the orthographic projections of each third sub-electrode and a fourth sub-electrode in the extension direction of the radio frequency modulation region overlap.

[0011] In some embodiments, the folded electro-optic modulator includes a substrate, an isolation layer, a waveguide layer, an insulating layer, and an electrode layer disposed sequentially, wherein a first waveguide arm and a second waveguide arm are located in the waveguide layer; a first main electrode, a second main electrode, a third main electrode, a first sub-electrode, a first connecting arm, a second sub-electrode, a second connecting arm, a third sub-electrode, a third connecting arm, a fourth sub-electrode, and a fourth connecting arm are located in the electrode layer; and the first connecting arm and the second connecting arm are insulated from the first waveguide arm by the insulating layer, and the third connecting arm and the fourth connecting arm are insulated from the second waveguide arm by the insulating layer.

[0012] In some embodiments, the waveguide layer is a ridge patterned layer; or, the waveguide layer is a ridge waveguide layer, including a planar layer and a ridge patterned layer located on the side of the planar layer away from the substrate, with a first waveguide arm and a second waveguide arm located in the ridge patterned layer.

[0013] In some embodiments, the waveguide layer is a ridge waveguide layer, including a planar layer and a ridge protrusion pattern layer located on the side of the planar layer away from the substrate, with a first waveguide arm and a second waveguide arm located on the ridge protrusion pattern layer; and an insulating layer covers the ridge protrusion pattern layer and exposes at least a portion of the planar layer, with a first main electrode, a second main electrode, and a third main electrode formed on the surface of the planar layer exposed by the insulating layer; or, an insulating layer covers the ridge protrusion pattern layer and covers at least a portion of the planar layer, with a first main electrode, a second main electrode, and a third main electrode formed on the surface of the portion of the insulating layer covering the planar layer.

[0014] In some embodiments, the protrusion structure formed by the portion of the insulating layer covering the first waveguide arm is located between the first sub-electrode and the first main electrode, and between the second sub-electrode and the second main electrode; and the protrusion structure formed by the portion of the insulating layer covering the second waveguide arm is located between the third sub-electrode and the second main electrode, and between the fourth sub-electrode and the third main electrode.

[0015] In some embodiments, a first sub-electrode and a second sub-electrode are formed on the surface of a protrusion structure formed on the portion of the insulating layer covering the first waveguide arm; and a third sub-electrode and a fourth sub-electrode are formed on the surface of a protrusion structure formed on the portion of the insulating layer covering the second waveguide arm.

[0016] In some embodiments, the folded electro-optic modulator further includes at least one of the following structures disposed in at least one odd-numbered radio frequency modulation region of the folded electro-optic modulator:

[0017] Multiple fifth sub-electrodes, each fifth sub-electrode is located between the first main electrode and the first waveguide arm and is connected to the side of the first main electrode near the first waveguide arm via a fifth connecting arm;

[0018] Multiple sixth sub-electrodes, each sixth sub-electrode is located between the second main electrode and the first waveguide arm and is connected to the side of the second main electrode closest to the first waveguide arm via a sixth connecting arm;

[0019] Multiple seventh sub-electrodes, each seventh sub-electrode located between the second main electrode and the second waveguide arm and connected to the side of the second main electrode closest to the second waveguide arm via a seventh connecting arm; and

[0020] Multiple eighth sub-electrodes, each eighth sub-electrode is located between the third main electrode and the second waveguide arm and is connected to the side of the third main electrode closest to the second waveguide arm via an eighth connecting arm.

[0021] In some embodiments, the substrate has a groove structure.

[0022] According to one or more embodiments of this disclosure, the folded electro-optic modulator, due to its folded design, can significantly reduce its length compared to conventional electro-optic modulators. To achieve better device performance, the length of the waveguide arm can be increased as needed, with minimal impact on the overall length of the device.

[0023] In addition, the first waveguide arm, the second waveguide arm, the first main electrode, the second main electrode, and the third main electrode all adopt a non-crossing design. Compared with some related technologies that use insulated crossings and are bridged by vias, the structural design is simpler and the requirements for manufacturing precision control are relatively lower, which helps to improve production efficiency and product yield, and reduce production costs.

[0024] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0025] Further details, features, and advantages of this disclosure are disclosed in the following description of exemplary embodiments in conjunction with the accompanying drawings, in which:

[0026] Figure 1 This is a simplified top view of a traditional electro-optic modulator;

[0027] Figure 2 This is a simplified top view of a folded electro-optic modulator according to some exemplary embodiments of the present disclosure;

[0028] Figure 3 This is a simplified top view of a folded electro-optic modulator according to some exemplary embodiments of the present disclosure;

[0029] Figure 4 This is a partial structural perspective view of a folded electro-optic modulator according to some exemplary embodiments of the present disclosure;

[0030] Figure 5 This is a partial structural perspective view of a folded electro-optic modulator according to some exemplary embodiments of the present disclosure;

[0031] Figure 6 This is a partial structural perspective view of a folded electro-optic modulator according to some exemplary embodiments of the present disclosure;

[0032] Figure 7 This is a partial structural perspective view of a folded electro-optic modulator according to some exemplary embodiments of the present disclosure;

[0033] Figure 8 This is a partial structural perspective view of a folded electro-optic modulator according to some exemplary embodiments of the present disclosure;

[0034] Figure 9 This is a partial structural perspective view of a folded electro-optic modulator according to some exemplary embodiments of the present disclosure; and

[0035] Figure 10 This is a partial structural perspective view of a folded electro-optic modulator according to some exemplary embodiments of the present disclosure. Detailed Implementation

[0036] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this disclosure. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0037] like Figure 1The diagram shows a schematic of a conventional Mach-Zehnder modulator. Ideally, the two waveguide arms 02 of the Mach-Zehnder modulator 001 are identical. When the Mach-Zehnder modulator 001 is not operating, neither waveguide arm 02 exhibits an electro-optic effect. The input light is split into two equal branches after passing through the beam splitter 01. The two branches remain in phase after passing through their respective waveguide arms 02. Therefore, a coherently enhanced signal from the beam combiner 05 is output from the beam combiner 05. When the Mach-Zehnder modulator 001 is working, the modulation electrode 04 (e.g., including signal electrode 040, first ground electrode 041 and second ground electrode 042) applies a modulation voltage to the two waveguide arms 02. After the two branch optical signals pass through one waveguide arm 02 respectively, their phases can differ by an odd multiple or an even multiple of Π. When the phase difference is an even multiple of Π, the optical combining element 05 outputs a coherent enhancement signal of the two branch optical signals. When the phase difference is an odd multiple of Π, the optical combining element 05 outputs a coherent cancellation signal of the two branch optical signals.

[0038] As shown in the figure, this traditional Mach-Zehnder modulator is characterized by its elongated structure, typically in the millimeter or centimeter range in length, while its width is usually in the hundreds of micrometers range. Furthermore, to minimize the driving voltage, the length of the two waveguide arms is often increased. Although the width of the Mach-Zehnder modulator is relatively small, its overall size is still primarily determined by its length. Therefore, achieving miniaturization of the device without compromising its performance is a crucial technical challenge for those skilled in the art.

[0039] This disclosure provides a foldable electro-optic modulator that enables miniaturization of the device while meeting performance requirements.

[0040] like Figure 2As shown, some embodiments of this disclosure provide a folded electro-optic modulator 100, including N radio frequency modulation regions 10 and N-1 turning regions 20, wherein N≥2. The folded electro-optic modulator 100 includes: a first waveguide arm 30 and a second waveguide arm 40 that are folded in shape and do not intersect each other; a first main electrode 111, a second main electrode 112, and a third main electrode 113 that are folded in shape and do not intersect each other; the first waveguide arm 30 is located between the first main electrode 111 and the second main electrode 112, and the second waveguide arm 40 is located between the second main electrode 112 and the third main electrode 113; the first main electrode 111 and the third main electrode 113 are ground electrodes for radio frequency signals, and the second main electrode 112 is a signal electrode for radio frequency signals; in addition, the folded electro-optic modulator 100 also includes a plurality of first sub-electrodes 1a, a plurality of second sub-electrodes 1b, a plurality of third sub-electrodes 1c, and a plurality of fourth sub-electrodes 1d disposed in radio frequency modulation regions 10 at any even-numbered position along the transmission direction of the first waveguide arm 30 and the second waveguide arm 40 (as shown by the dotted arrow in the figure). The sequence of each radio frequency modulation region 10 is arranged sequentially according to the transmission direction of the first waveguide arm 30 and the second waveguide arm 40.

[0041] like Figure 2 As shown, each first sub-electrode 1a is connected to the side of the first main electrode 111 near the second main electrode 112 via a first connecting arm 2a that crosses the first waveguide arm 30 insulated from it; each second sub-electrode 1b is connected to the side of the second main electrode 112 near the first main electrode 111 via a second connecting arm 2b that crosses the first waveguide arm 30 insulated from it; each third sub-electrode 1c is connected to the side of the second main electrode 112 near the third main electrode 113 via a third connecting arm 2c that crosses the second waveguide arm 40 insulated from it; and each fourth sub-electrode 1d is connected to the side of the third main electrode 113 near the second main electrode 112 via a fourth connecting arm 2d that crosses the second waveguide arm 40 insulated from it.

[0042] In this embodiment, to realize the input and output of optical signals, the folded electro-optic modulator 100 further includes an input element (e.g., a beam splitter 50) and an output element (e.g., a beam combiner 60). In this embodiment, the beam splitter 50 serves as the input element of the folded electro-optic modulator 100, including one input terminal and two output terminals. The beam combiner 60 serves as the output element of the folded electro-optic modulator 100, including two input terminals and one output terminal. A first waveguide arm 30 connects one output terminal of the beam splitter 50 and one input terminal of the beam combiner 60, and a second waveguide arm 40 connects the other output terminal of the beam splitter 50 and the other input terminal of the beam combiner 60. The structure of the input and output elements is not limited to the three-port element shown in the figure, and can be selected and designed according to the actual needs of the folded electro-optic modulator 100.

[0043] In this embodiment of the disclosure, N is a natural number and N≥2. It can be understood that when the number of RF modulation regions 10 is even (e.g., Figure 2 As shown (when N=2), the beam splitter 50 and the beam combiner 60 are located on the same side of the folded electro-optic modulator. When the number of radio frequency modulation zones is odd, the beam splitter and the beam combiner should be located on opposite sides of the folded electro-optic modulator.

[0044] The materials of the first waveguide arm 30 and the second waveguide arm 40 include electro-optic materials, such as lithium niobate, lithium tantalate, or potassium titanium phosphate. When radio frequency signals are input to the first main electrode 111, the second main electrode 112, and the third main electrode 113, in each radio frequency modulation region 10, the first waveguide arm 30 is in the electric field formed by multiple first sub-electrodes 1a and multiple second sub-electrodes 1b, and the second waveguide arm 40 is in the electric field formed by multiple third sub-electrodes 1c and multiple fourth sub-electrodes 1d, with the directions of the electric fields as shown by the dashed arrows in the figure.

[0045] Since the refractive index change of electro-optic materials is related to the direction of the electric field, if the electric field direction of the even-numbered RF modulation region is not reversed, the electric field direction of the even-numbered RF modulation region will be exactly opposite to that of the odd-numbered RF modulation region. This will cause the phase difference generated by the two waveguide arms in the odd-numbered RF modulation region to cancel each other out in the next even-numbered RF modulation region, thus making it impossible to achieve the optical modulation function.

[0046] Based on the above problems, the present disclosure provides an embodiment with the structure of the sub-electrode and connecting arm described above. For example... Figure 2 As shown, the electric fields formed by multiple first sub-electrodes 1a and multiple second sub-electrodes 1b, and the electric fields formed by multiple third sub-electrodes 1c and multiple fourth sub-electrodes 1d, are respectively indicated by the dashed arrows in the figure. It can be seen that the electric field directions of the first waveguide arm 30 in the first RF modulation region (i.e., the RF modulation region 10 located at the top in the figure) and the second RF modulation region (i.e., the RF modulation region 10 located at the bottom in the figure) are the same, and the electric field directions of the second waveguide arm 40 in the first RF modulation region and the second RF modulation region are the same.

[0047] The folded electro-optic modulator 100 provided in this disclosure, due to its folded design, can significantly reduce its length compared to traditional electro-optic modulators. To obtain better device performance, the length of the waveguide arm can be increased as needed, with minimal impact on the overall length of the device.

[0048] In addition, the first waveguide arm 30, the second waveguide arm 40, the first main electrode 111, the second main electrode 112 and the third main electrode 113 all adopt a non-crossing design. Compared with some related technologies that adopt an insulated cross and are bridged by vias, the structural design is simpler and the manufacturing precision control requirements are relatively lower, which helps to improve production efficiency and product yield and reduce production costs.

[0049] like Figure 2 As shown, in some embodiments of this disclosure, each first sub-electrode 1a and its corresponding first connecting arm 2a form a first T-shaped structure, and each second sub-electrode 1b and its corresponding second connecting arm 2b form a second T-shaped structure. Multiple first T-shaped structures and multiple second T-shaped structures are alternately arranged along the extension direction of the radio frequency modulation region 10 (which is also the extension direction of the two waveguide arms in the radio frequency modulation region 10). The gap between adjacent first sub-electrodes 1a is smaller than the length of the second sub-electrode 1b, and the gap between adjacent second sub-electrodes 1b is smaller than the length of the first sub-electrode 1a. The portions of the multiple first sub-electrodes 1a and multiple second sub-electrodes 1b arranged opposite each other can form an electric field, thereby enabling phase modulation of the light transmitted in the first waveguide arm 30.

[0050] Similarly, each third sub-electrode 1c and its corresponding third connecting arm 2c form a third T-shaped structure, and each fourth sub-electrode 1d and its corresponding fourth connecting arm 2d form a fourth T-shaped structure. Multiple third T-shaped structures and multiple fourth T-shaped structures are arranged alternately along the extension direction of the RF modulation region 10. The gap between adjacent third sub-electrodes 1c is smaller than the length of the fourth sub-electrode 1d, and the gap between adjacent fourth sub-electrodes 1d is smaller than the length of the third sub-electrode 1c. The opposing portions of the multiple third sub-electrodes 1c and multiple fourth sub-electrodes 1d can form an electric field, thereby enabling phase modulation of the light transmitted in the second waveguide arm 40.

[0051] like Figure 3 As shown, in some other embodiments of this disclosure, each first sub-electrode 1a and its corresponding first connecting arm 2a form a first L-shaped structure, and each second sub-electrode 1b and its corresponding second connecting arm 2b form a second L-shaped structure. Multiple first L-shaped structures and multiple second L-shaped structures are alternately arranged along the extension direction of the radio frequency modulation region 10, and the orthographic projections of each first sub-electrode 1a and a second sub-electrode 1b in the extension direction of the radio frequency modulation region 10 overlap. The portions of the multiple first sub-electrodes 1a and multiple second sub-electrodes 1b disposed opposite to each other can form an electric field, thereby enabling phase modulation of the light transmitted in the first waveguide arm 30.

[0052] Similarly, each third sub-electrode 1c and its corresponding third connecting arm 2c form a third L-shaped structure, and each fourth sub-electrode 1d and its corresponding fourth connecting arm 2d form a fourth L-shaped structure. Multiple third L-shaped structures and multiple fourth L-shaped structures are arranged alternately along the extension direction of the RF modulation region 10, and the orthographic projections of each third sub-electrode 1c and a fourth sub-electrode 1d in the extension direction of the RF modulation region 10 overlap. The opposing portions of the multiple third sub-electrodes 1c and multiple fourth sub-electrodes 1d can form an electric field, thereby enabling phase modulation of the light transmitted in the second waveguide arm 40.

[0053] The overall structure of the sub-electrode and connecting arm described above can be symmetrical or asymmetrical. This disclosure does not limit the specific shape of the sub-electrode and connecting arm, and is not limited to the above embodiments.

[0054] In the embodiments disclosed herein, such as Figure 4 As shown, the layer structure of the folded electro-optic modulator includes a substrate 151, an isolation layer 152, a waveguide layer 153, an insulating layer 154, and an electrode layer 155 arranged sequentially. The first waveguide arm 30 and the second waveguide arm 40 are located in the waveguide layer 153. The aforementioned first main electrode 111, second main electrode 112, third main electrode 113, first sub-electrode 1a, first connecting arm 2a, second sub-electrode 1b, second connecting arm 2b, third sub-electrode 1c, third connecting arm 2c, fourth sub-electrode 1d, and fourth connecting arm 2d are located in the electrode layer 155. The first connecting arm 2a and the second connecting arm 2b are insulated from the first waveguide arm 30 by the insulating layer 154, and the third connecting arm 2c and the fourth connecting arm 2d are insulated from the second waveguide arm 40 by the insulating layer 154. Some layer structures of the folded electro-optic modulator can be fabricated using mask patterning technology, and the specific materials used for each layer are not limited and can be selected according to actual needs.

[0055] like Figure 4 As shown, in some embodiments of this disclosure, the waveguide layer 153 is a ridge waveguide layer, including a planar layer 1531 and a ridge-protrusion patterned layer 1532 located on the side of the planar layer 1531 away from the substrate 151, with the first waveguide arm 30 and the second waveguide arm 40 located in the ridge-protrusion patterned layer 1532. In other embodiments of this disclosure, the waveguide layer 153 may also include only the ridge-protrusion patterned layer 1532 without including the planar layer 1531, and the first waveguide arm 30 and the second waveguide arm 40 are at least a portion of the ridge-protrusion patterned layer 1532.

[0056] like Figure 4 , Figure 5 , Figure 6 and Figure 7As shown, in this embodiment, the insulating layer 154 covers the ridge pattern layer 1532 and exposes at least a portion of the flat plate layer 1531, and the first main electrode 111, the second main electrode 112, and the third main electrode 113 are formed on the surface of the flat plate layer 1531 exposed by the insulating layer 154.

[0057] like Figure 8 and Figure 9 As shown, in some other embodiments of this disclosure, the insulating layer 154 covers the ridge pattern layer 1532 and at least a portion of the planar layer 1531, and the first main electrode 111, the second main electrode 112, and the third main electrode 113 are formed on the surface of the portion of the insulating layer 154 covering the planar layer 1531. In this embodiment, the insulating layer 154 covers the entire planar layer 1531, that is, the insulating layer 154 covers the entire waveguide layer 153.

[0058] like Figure 4 and Figure 5 As shown, in some embodiments of this disclosure, the protrusion 3a formed by the portion of the insulating layer 154 covering the first waveguide arm 30 is located between the first sub-electrode 1a and the first main electrode 111, and between the second sub-electrode 1b and the second main electrode 112. The protrusion 3b formed by the portion of the insulating layer 154 covering the second waveguide arm 40 is located between the third sub-electrode 1c and the second main electrode 112, and between the fourth sub-electrode 1d and the third main electrode. That is, each connecting arm spans the aforementioned protrusion structure of the insulating layer 154.

[0059] like Figure 6 , Figure 7 , Figure 8 and Figure 9 As shown, in some other embodiments of this disclosure, the first sub-electrode 1a and the second sub-electrode 1b are formed on the surface of the protrusion 3c formed on the portion of the insulating layer 154 covering the first waveguide arm 30, and the third sub-electrode 1c and the fourth sub-electrode 1d are formed on the surface of the protrusion 3d formed on the portion of the insulating layer 154 covering the second waveguide arm 40. That is, each connecting arm does not completely cross the aforementioned protrusion structure of the insulating layer 154.

[0060] Regardless of whether the connecting arm completely crosses the aforementioned protrusion structure of the insulating layer 154, the connecting arm is insulated from the waveguide arm, so that the sub-electrode and the corresponding main electrode are located on both sides of the waveguide arm, thereby ensuring the consistency of the electric field direction applied to the waveguide arm.

[0061] like Figure 3 As shown, in some embodiments of this disclosure, the folded electro-optic modulator 100 further includes at least one of the following structures disposed in at least one odd-numbered radio frequency modulation region 10:

[0062] Multiple fifth sub-electrodes 1e, each fifth sub-electrode 1e is located between the first main electrode 111 and the first waveguide arm 30 and is connected to the side of the first main electrode 111 near the first waveguide arm 30 through a fifth connecting arm 2e;

[0063] Multiple sixth sub-electrodes 1f, each sixth sub-electrode 1f is located between the second main electrode 112 and the first waveguide arm 30 and is connected to the side of the second main electrode 112 near the first waveguide arm 30 through a sixth connecting arm 2f;

[0064] Multiple seventh sub-electrodes 1g, each seventh sub-electrode 1g located between the second main electrode 112 and the second waveguide arm 40 and connected to the side of the second main electrode 112 closest to the second waveguide arm 40 via a seventh connecting arm 2g; and

[0065] Multiple eighth sub-electrodes 1h, each eighth sub-electrode 1h is located between the third main electrode 113 and the second waveguide arm 40 and is connected to the side of the third main electrode 113 near the second waveguide arm 40 through an eighth connecting arm 2h.

[0066] The fifth sub-electrode 1e, the sixth sub-electrode 1f, the seventh sub-electrode 1g, and the eighth sub-electrode 1h can be selected and configured as needed, and their number and shape can also be designed accordingly. By selecting and configuring these sub-electrodes, impedance mismatches that may exist in different regions of the folded electro-optic modulator 100 can be mitigated, and microwave reflections of electrical signals can be reduced, thereby further improving the device's performance. Furthermore, since the speed of light transmission is generally greater than the speed of electrical transmission, the design of these sub-electrodes can, to some extent, compensate for the difference in transmission speeds between optical and electrical signals, ensuring a better match between the transmission of the optical and electric fields, thus further improving the device performance of the folded electro-optic modulator.

[0067] Similarly, such as Figure 10 As shown, the fifth sub-electrode 1e and the sixth sub-electrode 1f can be disposed on the surface of the protruding structure 3e shown in the figure, and the seventh sub-electrode 1g and the eighth sub-electrode 1h can be disposed on the surface of the protruding structure 3f shown in the figure. In some other embodiments, the fifth and sixth sub-electrodes can also be disposed on both sides of the protruding structure, and the fifth and sixth connecting arms do not cross the protruding structure; similarly, the seventh and eighth sub-electrodes can also be disposed on both sides of the protruding structure, and the seventh and eighth connecting arms do not cross the protruding structure.

[0068] like Figure 5 , Figure 7 and Figure 8 As shown, in some embodiments of this disclosure, the substrate 151 has a groove structure 1510 formed toward the isolation layer 152.

[0069] Since the speed of light transmission is generally greater than the speed of electrical transmission, the groove structure 1510 on the substrate 151 in this embodiment can reduce the propagation constant of the electrical signal to a certain extent, thereby increasing the transmission speed of the electrical signal to compensate for the difference in transmission speed. This allows the transmission of the optical field and the electric field in the radio frequency modulation region to be matched as much as possible, thereby further improving the device performance of the folded electro-optic modulator. In other embodiments of this disclosure, the groove structure may also be designed with other orientations according to actual needs, and this disclosure does not specifically limit it in this regard.

[0070] In some embodiments of this disclosure, such as Figure 3 As shown, the folded electro-optic modulator 100 further includes a phase compensation modulation module 70 disposed between the aforementioned electrode structure and the beam combining element 60. The phase compensation modulation module 70 can modulate the first waveguide arm 30 and the second waveguide arm 40 as needed, thereby compensating for the inherent phase difference between the two waveguide arms and further improving the accuracy of the modulation output of the electro-optic modulator. The phase compensation modulation module 70 is not limited to the aforementioned location; for example, it can also be disposed between the beam splitting element 50 and the aforementioned electrode structure.

[0071] The specific type of the phase compensation modulation module 70 is not limited. For example, it can be an electro-optic phase compensation modulation module based on the electro-optic effect, or a thermo-optic phase compensation modulation module based on the thermo-optic effect, and so on. When the phase compensation modulation module 70 is an electro-optic phase compensation modulation module based on the electro-optic effect, some of its layer structures can be fabricated in the same layer as some of the layer structures of the aforementioned folded electro-optic modulator to simplify the process and reduce manufacturing costs.

[0072] In some embodiments, the phase compensation modulation module 70 may be omitted as needed.

[0073] In summary, the foldable electro-optic modulator 100 provided in this embodiment can achieve miniaturized device design while meeting device performance requirements, thus making it easier to integrate into a hardware system.

[0074] It should be understood that in this specification, the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship or dimensions based on the orientation or positional relationship or dimensions shown in the accompanying drawings. These terms are used only for ease of description and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this disclosure.

[0075] Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0076] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0077] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0078] This specification provides many different implementations or examples that can be used to implement this disclosure. It should be understood that these different implementations or examples are entirely exemplary and are not intended to limit the scope of this disclosure in any way. Those skilled in the art will be able to conceive of various variations or substitutions based on the disclosure of this specification, and these should all be covered within the scope of this disclosure. Therefore, the scope of this disclosure should be determined by the scope defined in the appended claims.

Claims

1. A folded electro-optic modulator, comprising: The first and second waveguide arms are folded in shape and do not intersect each other. The materials of the first and second waveguide arms include electro-optic materials. The first, second, and third main electrodes are folded in shape and do not intersect each other. The first waveguide arm is located between the first and second main electrodes, and the second waveguide arm is located between the second and third main electrodes. The first and third main electrodes are ground electrodes for radio frequency signals, and the second main electrode is the signal electrode for radio frequency signals. as well as Along the transmission directions of the first and second waveguide arms, the following structure is provided in the radio frequency modulation region of any even-numbered position of the folded electro-optic modulator: Multiple first sub-electrodes, each first sub-electrode being connected to the side of the first main electrode near the second main electrode via a first connecting arm that is insulated from and intersects with the first waveguide arm; Multiple second sub-electrodes, each second sub-electrode being connected to the side of the second main electrode closest to the first main electrode via a second connecting arm that intersects with and is insulated from the first waveguide arm; Multiple third sub-electrodes, each third sub-electrode being connected to the side of the second main electrode near the third main electrode via a third connecting arm that crosses and is insulated from the second waveguide arm; as well as Multiple fourth sub-electrodes, each fourth sub-electrode being connected to the side of the third main electrode closest to the second main electrode via a fourth connecting arm that intersects with and is insulated from the second waveguide arm. The electric field directions of the first waveguide arm in the odd-numbered RF modulation region and the even-numbered RF modulation region are the same. Furthermore, the electric field directions of the second waveguide arm in the odd-numbered RF modulation region and the even-numbered RF modulation region are the same.

2. The folded electro-optic modulator according to claim 1, wherein, Each first sub-electrode and its corresponding first connecting arm form a first T-shaped structure, and each second sub-electrode and its corresponding second connecting arm form a second T-shaped structure. Multiple first T-shaped structures and multiple second T-shaped structures are arranged alternately along the extension direction of the radio frequency modulation region. The gap between adjacent first sub-electrodes is smaller than the length of the second sub-electrode, and the gap between adjacent second sub-electrodes is smaller than the length of the first sub-electrode. as well as Each third sub-electrode and its corresponding third connecting arm form a third T-shaped structure, and each fourth sub-electrode and its corresponding fourth connecting arm form a fourth T-shaped structure. Multiple third T-shaped structures and multiple fourth T-shaped structures are arranged alternately along the extension direction of the RF modulation region. The gap between adjacent third sub-electrodes is smaller than the length of the fourth sub-electrode, and the gap between adjacent fourth sub-electrodes is smaller than the length of the third sub-electrode.

3. The folded electro-optic modulator according to claim 1, wherein, Each first sub-electrode and its corresponding first connecting arm form a first L-shaped structure, and each second sub-electrode and its corresponding second connecting arm form a second L-shaped structure. Multiple first L-shaped structures and multiple second L-shaped structures are arranged alternately along the extension direction of the radio frequency modulation region. The orthographic projections of each first sub-electrode and a second sub-electrode in the extension direction of the radio frequency modulation region overlap. as well as Each third sub-electrode and its corresponding third connecting arm form a third L-shaped structure, and each fourth sub-electrode and its corresponding fourth connecting arm form a fourth L-shaped structure. Multiple third L-shaped structures and multiple fourth L-shaped structures are arranged alternately along the extension direction of the radio frequency modulation region, and the orthogonal projections of each third sub-electrode and a fourth sub-electrode in the extension direction of the radio frequency modulation region overlap.

4. The folded electro-optic modulator according to claim 1, wherein, The folded electro-optic modulator comprises a substrate, an isolation layer, a waveguide layer, an insulating layer, and an electrode layer arranged sequentially, wherein... The first and second waveguide arms are located in the waveguide layer; The first main electrode, the second main electrode, the third main electrode, the first sub-electrode, the first connecting arm, the second sub-electrode, the second connecting arm, the third sub-electrode, the third connecting arm, the fourth sub-electrode, and the fourth connecting arm are located in the electrode layer; and The first connecting arm and the second connecting arm are insulated from the first waveguide arm by an insulating layer, and the third connecting arm and the fourth connecting arm are insulated from the second waveguide arm by an insulating layer.

5. The folded electro-optic modulator according to claim 4, wherein, The waveguide layer is a ridge patterned layer; or, the waveguide layer is a ridge waveguide layer, comprising a planar layer and a ridge patterned layer located on the side of the planar layer away from the substrate, with a first waveguide arm and a second waveguide arm located in the ridge patterned layer.

6. The folded electro-optic modulator according to claim 4, wherein, The waveguide layer is a ridge waveguide layer, including a flat plate layer and a ridge protrusion pattern layer located on the side of the flat plate layer away from the substrate, with the first waveguide arm and the second waveguide arm located in the ridge protrusion pattern layer. as well as An insulating layer covers the ridge pattern layer and exposes at least a portion of the flat plate layer, with a first main electrode, a second main electrode, and a third main electrode formed on the surface of the flat plate layer exposed by the insulating layer; or, an insulating layer covers the ridge pattern layer and covers at least a portion of the flat plate layer, with a first main electrode, a second main electrode, and a third main electrode formed on the surface of the portion of the insulating layer covering the flat plate layer.

7. The folded electro-optic modulator according to claim 4, wherein, The protruding structure formed by the portion of the insulating layer covering the first waveguide arm is located between the first sub-electrode and the first main electrode, and between the second sub-electrode and the second main electrode; as well as The protruding structure formed by the portion of the insulating layer covering the second waveguide arm is located between the third sub-electrode and the second main electrode, and between the fourth sub-electrode and the third main electrode.

8. The folded electro-optic modulator according to claim 4, wherein, The first sub-electrode and the second sub-electrode are formed on the surface of the protrusion structure formed on the portion of the insulating layer covering the first waveguide arm; as well as The third and fourth sub-electrodes are formed on the surface of the raised structure formed on the portion of the insulating layer covering the second waveguide arm.

9. The folded electro-optic modulator according to any one of claims 1 to 8, further comprising at least one of the following structures disposed in at least one odd-numbered radio frequency modulation region of the folded electro-optic modulator: Multiple fifth sub-electrodes, each fifth sub-electrode is located between the first main electrode and the first waveguide arm and is connected to the side of the first main electrode near the first waveguide arm via a fifth connecting arm; Multiple sixth sub-electrodes, each sixth sub-electrode is located between the second main electrode and the first waveguide arm and is connected to the side of the second main electrode closest to the first waveguide arm via a sixth connecting arm; Multiple seventh sub-electrodes, each seventh sub-electrode is located between the second main electrode and the second waveguide arm and is connected to the side of the second main electrode near the second waveguide arm via a seventh connecting arm; as well as Multiple eighth sub-electrodes, each eighth sub-electrode is located between the third main electrode and the second waveguide arm and is connected to the side of the third main electrode closest to the second waveguide arm via an eighth connecting arm.

10. The folded electro-optic modulator according to any one of claims 1 to 8, wherein, The substrate has a groove structure.

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