Folding Mach-Zehnder modulation device and electro-optical modulator
By designing a folded Mach-Zehnder modulation device, group velocity matching between optical and radio frequency signals was achieved, solving the problems of limited modulation efficiency and bandwidth in optical communication, and realizing the miniaturization and high-efficiency modulation of the device.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- NANJING LYCORE TECH CO LTD
- Filing Date
- 2025-04-02
- Publication Date
- 2026-04-17
AI Technical Summary
In existing optical modulators for optical communication, the difference in group velocity matching characteristics between the RF electrodes and the optical waveguide leads to an unstable phase relationship between the modulated signal and the optical wave, resulting in decreased modulation efficiency, limited bandwidth, and signal distortion. Furthermore, the increased loss in the high-frequency range exacerbates these problems.
A folded Mach-Zehnder modulation device is adopted, with the first and second waveguide arms arranged in a folded and non-overlapping sequence. Combined with the configuration of the radio frequency electrodes, the transmission distance of the optical signal and the radio frequency signal is adjusted by the turning zone to achieve secondary matching of the group velocity.
It improves modulation bandwidth and efficiency, reduces device length, avoids losses and crosstalk caused by waveguide crossings, improves electro-optic response at high frequencies, and enhances signal quality.
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Figure CN224137576U_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of optical communications, and in particular to a folded Mach-Zehnder modulation device and an electro-optic modulator. Background Technology
[0002] In optical communication, the operating bandwidth and modulation efficiency of optical modulators are primarily limited by the group velocity matching characteristics between the RF electrodes and the optical waveguide. Because the propagation speed of the RF signal in the metal electrodes differs from that of the optical signal in the waveguide, group velocity mismatch can occur within the modulation region. This makes it difficult to maintain a stable phase relationship between the modulated signal and the optical wave across the entire frequency band, leading to reduced modulation efficiency, limited bandwidth, and signal distortion. Furthermore, in the high-frequency range, both conductor losses and dielectric losses increase significantly with increasing frequency, further exacerbating the impact of group velocity mismatch on bandwidth and signal quality.
[0003] Existing modulator technologies have yet to provide a satisfactory solution to the group velocity mismatch problem within the modulation region. Because the group velocities of the radio frequency signal and the optical signal cannot maintain high consistency throughout the entire modulation region, modulation bandwidth and efficiency are limited. Utility Model Content
[0004] In view of the above problems, this disclosure provides a folded Mach-Zehnder modulation device, which can improve modulation bandwidth and modulation efficiency. This disclosure also provides an electro-optic modulator.
[0005] According to a first aspect of this disclosure, a folded Mach-Zehnder modulation device is provided, comprising a first modulation region, a turning region, and a second modulation region extending sequentially along the optical signal transmission direction, wherein the turning region connects the first modulation region and the second modulation region. The folded Mach-Zehnder modulation device includes: a first waveguide arm and a second waveguide arm, the first and second waveguide arms being folded in an integral shape and arranged sequentially without crossing in the turning region, the first and second waveguide arms having optical signal modulation sections; and radio frequency electrodes, comprising a plurality of strip electrodes being folded in an integral shape and arranged sequentially without crossing, configured to apply a radio frequency voltage to the first waveguide arm and / or the second waveguide arm. Along the direction of optical signal transmission, the optical signal modulation section includes a basic modulation section, an in-phase modulation section, and an out-of-phase modulation section in sequence. The basic modulation section is located in the first modulation region, and the out-of-phase modulation section is located in the second modulation region. The first waveguide arm and the second waveguide arm generate a certain phase difference in the basic modulation section. The first waveguide arm and the second waveguide arm generate a phase difference in the in-phase modulation section that is in phase with the phase difference generated in the basic modulation section. The first waveguide arm and the second waveguide arm generate a phase difference in the out-of-phase modulation section that is out of phase with the phase difference generated in the basic modulation section.
[0006] In some embodiments, the in-phase modulation segment and the out-of-phase modulation segment are of equal length.
[0007] In some embodiments, the radio frequency electrode includes: an outer ground electrode, a negative signal electrode, a middle ground electrode, a positive signal electrode, and an inner ground electrode arranged in sequence without crossing.
[0008] In some embodiments, the radio frequency electrode includes a first spacing group and a second spacing group among a plurality of strip electrodes, either adjacent or spaced apart from each other. Specifically, in a direction perpendicular to the optical signal transmission direction, the first spacing group includes a first spacing located above the positive signal electrode and below the negative signal electrode, and the second spacing group includes a second spacing located below the positive signal electrode and above the negative signal electrode. Specifically, in the basic modulation section and the in-phase modulation section, a first waveguide arm is arranged within any first spacing of the first spacing group, and a second waveguide arm is arranged within any second spacing of the second spacing group; and in the in-phase modulation section, a first waveguide arm is arranged within any second spacing of the second spacing group, and a second waveguide arm is arranged within any first spacing of the first spacing group.
[0009] In some embodiments, the in-phase modulation section is located in the second modulation region, such that the optical signal enters the in-phase modulation section from the basic modulation section via the turning region, and then enters the out-of-phase modulation section.
[0010] In some embodiments, the in-phase modulation section is located in the first modulation region, such that the optical signal enters the in-phase modulation section from the basic modulation section and then enters the out-of-phase modulation section via the turning region.
[0011] In some embodiments, the first waveguide arm and the second waveguide arm turn synchronously with the RF electrode; or the first waveguide arm and the second waveguide arm lag behind the RF electrode in turning; or the first waveguide arm and the second waveguide arm lead the RF electrode in turning.
[0012] In some embodiments, the folded Mach-Zehnder modulation device further includes: a beam splitter for splitting the input optical signal into two paths and then feeding them into the first waveguide arm and the second waveguide arm respectively; and a beam combiner for combining the two optical signals from the first waveguide arm and the second waveguide arm and then outputting them.
[0013] In some embodiments, the folded Mach-Zehnder modulation device includes a substrate, an isolation layer, a waveguide layer, an electrode layer, and an insulating material layer disposed sequentially, wherein a first waveguide arm and a second waveguide arm are located in the waveguide layer, and an RF electrode is located in the electrode layer, wherein, in a projection in a direction perpendicular to the substrate, the first waveguide arm and the second waveguide arm overlap with the electrode in the RF electrode in the turning region, or the first waveguide arm and the second waveguide arm overlap with the RF electrode in the region between the in-phase modulation segment and the out-of-phase modulation segment.
[0014] According to a second aspect of this disclosure, an electro-optic modulator is provided, including the folded Mach-Zehnder modulation device described in the above embodiments.
[0015] According to one or more embodiments of this disclosure, the folded design significantly reduces the length dimension compared to conventional Mach-Zehnder modulators. The first and second waveguide arms are arranged sequentially without crossing in the turning region, avoiding losses and crosstalk caused by waveguide crossings.
[0016] In the technical solution of this embodiment, a turning region is provided between the first modulation region and the second modulation region. In this design, the transmission distance of the optical signal and the radio frequency signal can be adjusted by configuring the respective turning curvatures of the waveguide arm and the strip electrode. Given the difference between the propagation speed of the radio frequency signal in the metal electrode and the propagation speed of the optical signal in the waveguide, the beneficial effects of this design are: achieving secondary group velocity matching between the optical signal and the radio frequency signal, maintaining a stable phase relationship between the modulation signal and the light wave within the modulation region, and improving the modulation bandwidth and modulation efficiency.
[0017] It should be understood that the above description is only an overview of the technical solution of this disclosure. In order to better understand the technical means of this disclosure and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of this disclosure more obvious and understandable, specific embodiments of this disclosure are given below. Attached Figure Description
[0018] It should be noted that the accompanying drawings are for illustrative purposes only and should not be considered as limiting the scope of this disclosure. The drawings are not necessarily drawn to scale, and the dimensions of some features may be exaggerated for clarity. The same reference numerals denote the same parts throughout the drawings. For clarity, the same parts may not be shown in all drawings.
[0019] In the attached diagram:
[0020] Figures 1a-1c A schematic diagram of the structure of a folded Mach-Zehnder modulator according to some embodiments of the present disclosure is shown;
[0021] Figures 2a-2b A schematic diagram of the structure of a folded Mach-Zehnder modulator according to other embodiments of the present disclosure is shown;
[0022] Figure 3 A schematic diagram of the structure of a folded Mach-Zehnder modulator according to other embodiments of the present disclosure is shown.
[0023] The reference numerals in the detailed embodiments are as follows:
[0024] 100-fold Mach-Zehnder Modulation Device
[0025] 1. Input terminal
[0026] 2 Output terminal
[0027] 10 First Waveguide Arm
[0028] 20 Second Waveguide Arm
[0029] 30 optical signal modulation sections
[0030] 301 basic modulation segment
[0031] 302 In-phase modulation section
[0032] 303 Switching Transition Section
[0033] 304 Inverting Modulation Section
[0034] 40 beam splitters
[0035] 50 RF electrodes
[0036] 510 outer ground electrode
[0037] 520 negative signal electrode
[0038] 530 intermediate ground electrode
[0039] 540 positive signal electrode
[0040] 550 inner ground electrode
[0041] 60-in-1 optical element
[0042] U1, U2, U3, U4 First Interval
[0043] D1, D2, D3, D4 Second Interval
[0044] S1 First Modulation Region
[0045] ST Turning Area
[0046] S2 Second Modulation Region Detailed Implementation
[0047] The embodiments of the technical solutions disclosed herein will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solutions disclosed herein and are therefore intended to limit the scope of protection of this disclosure.
[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure; the terms “comprising” and “having”, and any variations thereof, in the specification, claims and foregoing description of the drawings of this disclosure are intended to cover non-exclusive inclusion.
[0049] In the description of the embodiments of this disclosure, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.
[0050] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0051] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.
[0052] In the description of the embodiments of this disclosure, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).
[0053] In the description of the embodiments of this disclosure, the technical terms "center," "longitudinal," "lateral," "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 based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this disclosure.
[0054] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" 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 or an electrical 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 the embodiments of this disclosure according to the specific circumstances.
[0055] Existing Mach-Zehnder modulators are typically characterized by their elongated structure, with lengths usually on the order of millimeters or centimeters and widths typically on the order of hundreds of micrometers. 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 performance is a pressing technical problem for those skilled in the art. On the other hand, due to the difference in propagation speed between the radio frequency signal in the metal electrodes and the optical signal in the waveguide, the transmission paths of the radio frequency and optical signals are roughly the same for this type of linear modulator. Therefore, avoiding the decrease in modulation efficiency, bandwidth limitation, and signal distortion caused by group velocity mismatch in the modulation region is also a pressing technical problem for those skilled in the art.
[0056] This disclosure provides a folded Mach-Zehnder modulation device that can improve modulation bandwidth and modulation efficiency. The folded Mach-Zehnder modulation device of this disclosure can be used in electro-optic modulators.
[0057] Figures 1a-1c A schematic diagram of the structure of a folded Mach-Zehnder modulator 100 according to some embodiments of the present disclosure is shown. (Refer to...) Figure 1a and Figure 1bThe folded Mach-Zehnder modulation device 100 includes a first modulation region S1, a turning region ST, and a second modulation region S2 extending sequentially along the optical signal transmission direction. The turning region ST connects the first modulation region S1 and the second modulation region S2. The folded Mach-Zehnder modulation device 100 includes a first waveguide arm 10, a second waveguide arm 20, and an RF electrode 50. The first waveguide arm 10 and the second waveguide arm 20 are folded in shape and arranged sequentially without crossing at the turning region ST. The first waveguide arm 10 and the second waveguide arm 20 have optical signal modulation sections. The RF electrode 50 includes multiple strip electrodes 510, 520, 530, 540, and 550 that are folded in shape and arranged sequentially without crossing, configured to apply an RF voltage to the first waveguide arm 10 and / or the second waveguide arm 20. Along the optical signal transmission direction, the optical signal modulation section sequentially includes a basic modulation section 301, an in-phase modulation section 302, and an out-of-phase modulation section 304. The basic modulation segment 301 is located in the first modulation region S1, and the inverted modulation segment 304 is located in the second modulation region S2. The first waveguide arm 10 and the second waveguide arm 20 generate a certain phase difference ΔΦ1 in the basic modulation segment 301. The first waveguide arm 10 and the second waveguide arm 20 generate a phase difference ΔΦ2 in the in-phase modulation segment 302 that is in phase with the phase difference ΔΦ1 generated in the basic modulation segment 301. The first waveguide arm 10 and the second waveguide arm 20 generate a phase difference ΔΦ3 in the inverted modulation segment 304 that is out of phase with the phase difference ΔΦ1 generated in the basic modulation segment 301.
[0058] The folded Mach-Zehnder modulator 100 provided in the embodiments of this disclosure, due to its folded design, can significantly reduce its length dimension compared to conventional Mach-Zehnder 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.
[0059] Both the first waveguide arm 10 and the second waveguide arm 20 are made of electro-optic materials, such as lithium niobate, lithium tantalate, or potassium titanium phosphate. The first waveguide arm 10 and the second waveguide arm 20 are folded and arranged sequentially without crossing in the turning region ST, which avoids transmission loss and crosstalk caused by crossing structures. The first waveguide arm 10 and the second waveguide arm 20 are curved in a concentric arc shape in the turning region ST, which facilitates manufacturing and minimizes electrical transmission loss. Of course, this disclosure does not impose specific limitations, and the first waveguide arm 10 and the second waveguide arm 20 can be designed with other shapes in the turning region ST as needed.
[0060] A turning zone ST is provided between the first modulation zone S1 and the second modulation zone S2. In this design, the transmission distances of the optical signal and the radio frequency signal can be changed by configuring the respective turning curvatures of the waveguide arms 10, 20 and the strip electrode 50, thereby achieving secondary matching of the group velocity, stabilizing the phase relationship between the modulation signal and the optical wave in the modulation zones S1 and S2, and improving the modulation bandwidth and modulation efficiency.
[0061] In some embodiments of this disclosure, the in-phase modulation section 302 and the out-of-phase modulation section 304 are of equal length. Since the phase difference ΔΦ3 generated by waveguide arms 10 and 20 in the out-of-phase modulation section 304 is out of phase with the phase difference ΔΦ2 generated in the in-phase modulation section 302, at low frequencies, due to low RF transmission loss, the modulation electric field strength in the second modulation region S2 decreases very little, and the phase differences ΔΦ3 and ΔΦ2 can cancel each other out. In this case, the optical signal is mainly modulated by the basic modulation section 301. At high frequencies, the RF transmission loss increases along the optical signal transmission direction, and the modulation electric field strength in the second modulation region S2 weakens. The phase difference ΔΦ3 generated by the out-of-phase modulation section 304 and the phase difference ΔΦ2 generated by the in-phase modulation section 302 cannot cancel each other out. Furthermore, the higher the operating frequency, the less phase difference is canceled out. In this case, the optical signal is modulated not only by the basic modulation section 301 but also by the in-phase modulation section 302 and the out-of-phase modulation section 304. This differential modulator structure can improve the electro-optic response at high frequencies, has an optical bandwidth compensation effect, and can increase the modulator's operating bandwidth.
[0062] In some embodiments of this disclosure, the radio frequency electrode 50 includes an outer ground electrode 510, a negative signal electrode 520, a middle ground electrode 530, a positive signal electrode 540, and an inner ground electrode 550 arranged sequentially without crossing. Alternatively, the order of the negative signal electrode and the positive signal electrode can be interchanged, and this disclosure is not limiting in this regard. It should be understood that adjacent electrodes have different potentials, thus forming a modulation electric field between the electrodes.
[0063] In some embodiments of this disclosure, the radio frequency electrode 50 includes a first spacing group and a second spacing group between adjacent or spaced-apart adjacent strip electrodes. For example... Figure 1cAs shown, in a direction perpendicular to the optical signal transmission direction, the first spacing group includes first spacings U1, U2, U3, and U4 located above the positive signal electrode 540 and below the negative signal electrode 520, and the second spacing group includes second spacings D1, D2, D3, and D4 located below the positive signal electrode 540 and above the negative signal electrode 520. In the basic modulation section 301 and the in-phase modulation section 302, the first waveguide arm 10 is arranged within any first spacing in the first spacing group, and the second waveguide arm 20 is arranged within any second spacing in the second spacing group. In the out-of-phase modulation section 304, the first waveguide arm 10 is arranged within any second spacing in the second spacing group, and the second waveguide arm 20 is arranged within any first spacing in the first spacing group. Alternatively, the first and second waveguide arms can also be arranged in the reverse manner. Figure 1c As shown, within the first intervals U1, U2, U3, and U4, the electric field direction is upward, while within the second intervals D1, D2, D3, and D4, the electric field direction is downward.
[0064] Example 1
[0065] The following will combine Figures 1a-1c Some embodiments of this disclosure will be described. In the basic modulation section 301 and the in-phase modulation section 302, the first waveguide arm 10 is arranged within the second intervals D1 and D3, respectively, and the second waveguide arm 20 is arranged within the first intervals U1 and U3, respectively. In the out-of-phase modulation section 304, the first waveguide arm 10 is arranged within the first interval U4, and the second waveguide arm 20 is arranged within the second interval D4. The electric field directions applied by the radio frequency electrode 50 to the first waveguide arm 10 and the second waveguide arm 20 are always opposite.
[0066] In this embodiment, the in-phase modulation section 302 is located in the second modulation region S2, allowing the optical signal to enter the in-phase modulation section 302 from the basic modulation section 301 via the turning region ST, and subsequently enter the out-of-phase modulation section 304. The optical signal modulation section also includes a switching transition section 303 disposed between the in-phase modulation section 302 and the out-of-phase modulation section 304. In the switching transition section 303, each of the two waveguide arms switches from its original interval to another interval with the opposite electric field direction. Specifically, the first waveguide arm 10 enters the second interval D3 from the second interval D1 via the turning region ST. After folding through the turning region, the direction of the electric field of the first waveguide arm 10 does not change and remains the same as before the turn. Along the optical signal transmission direction, the first waveguide arm then switches from the second interval D3 located in the in-phase modulation section 302 to the first interval U4 located in the out-of-phase modulation section 304 via the switching transition section 303. After the switch, the direction of the electric field of the first waveguide arm 10 is opposite to that before. Similarly, the second waveguide arm 20 enters the first interval U3 from the first interval U1 via the turning zone ST. After folding through the turning zone, the direction of the electric field of the second waveguide arm 20 does not change. Following the optical signal transmission direction, the second waveguide arm then switches from the first interval U3 located in the in-phase modulation section 302 to the second interval D4 located in the out-of-phase modulation section 304 via the switching transition section 303. After the switch, the direction of the electric field of the second waveguide arm 20 is opposite to that before.
[0067] Example 2
[0068] The following will combine Figures 2a-2b Some other embodiments of this disclosure will be described. In the basic modulation section 301 and the in-phase modulation section 302, the first waveguide arm 10 is always arranged within the second interval D1, and the second waveguide arm 20 is always arranged within the first interval U2. In the out-of-phase modulation section 304, the first waveguide arm 10 is arranged within the first interval U4, and the second waveguide arm 20 is arranged within the second interval D3. The electric field directions applied by the radio frequency electrode 50 to the first waveguide arm 10 and the second waveguide arm 20 are always opposite.
[0069] In this embodiment, the in-phase modulation section 302 is also located in the first modulation region S1. The optical signal enters the in-phase modulation section 302 from the basic modulation section 301, and then enters the inverting modulation section 304 via the turning region ST. As described above... Figures 1a-1cCompared to the illustrated embodiment, in this embodiment, the optical signal modulation section does not require a switching transition section 303. Since the in-phase modulation section 302 is arranged in the first modulation region S1, the waveguide arm can switch its current interval while passing through the turning region ST. Figuratively, the turning region in this embodiment "acts" as a switching transition section. Specifically, the first waveguide arm 10 switches from the second interval D1 to the first interval U4 via the turning region ST, and after folding through the turning region, the direction of the electric field of the first waveguide arm 10 changes, becoming opposite to that before the turn. Similarly, the second waveguide arm 20 switches from the first interval U2 to the second interval D3 via the turning region ST, and after folding through the turning region, the direction of the electric field of the second waveguide arm 20 changes, becoming opposite to that before the turn.
[0070] In Embodiments 1 and 2 described above, the first waveguide arm 10 and the second waveguide arm 20 lead the turning of the RF electrode 50. This allows the optical signal to have a shorter transmission distance than the RF signal. Alternatively, in other embodiments of this disclosure, the first waveguide arm 10 and the second waveguide arm 20 may also be synchronized with the turning of the RF electrode 50. Alternatively, in other embodiments of this disclosure, the first waveguide arm 10 and the second waveguide arm 20 may also lag behind the turning of the RF electrode 50. The respective turning rates of the waveguide arms and the strip electrodes can be configured according to actual needs, thereby adjusting the transmission distances of the optical and RF signals. Given the difference between the propagation speed of the RF signal in the metal electrode and the propagation speed of the optical signal in the waveguide, the beneficial effects of this design are: achieving secondary group velocity matching between the optical and RF signals, maintaining a stable phase relationship between the modulation signal and the light wave within the modulation region, and improving modulation bandwidth and modulation efficiency.
[0071] Reference Figure 3 In some embodiments of this disclosure, the folded Mach-Zehnder modulation device 100 further includes a beam splitter 40 and a beam combiner 60. The beam splitter 40 is used to split the input optical signal from the input terminal 1 into two paths and then guide them to the first waveguide arm 10 and the second waveguide arm 20, respectively. The beam combiner 60 is used to combine the two optical signals from the first waveguide arm 10 and the second waveguide arm 20 and then output them to the output terminal 2.
[0072] In some embodiments of this disclosure, the folded Mach-Zehnder modulation device 100 further includes a substrate, an isolation layer, a waveguide layer, an electrode layer, and an insulating material layer disposed sequentially, wherein the first waveguide arm 10 and the second waveguide arm 20 are located in the waveguide layer, and the radio frequency electrode 50 is located in the electrode layer. In a projection perpendicular to the substrate, the first waveguide arm 10 and the second waveguide arm 20 overlap with the electrode in the radio frequency electrode 50 in the turning region ST, or the first waveguide arm and the second waveguide arm overlap with the radio frequency electrode 50 in the region between the in-phase modulation section 302 and the out-of-phase modulation section 304.
[0073] For example, in the case of the folded Mach-Zehnder modulation device 100 arranged in accordance with the above embodiment 1, since a switching transition section 303 is provided between the in-phase modulation section 302 and the out-of-phase modulation section 304, the first waveguide arm and the second waveguide arm overlap with the radio frequency electrode 50 in the switching transition section 303.
[0074] For example, if the first waveguide arm 10 and the second waveguide arm 20 turn ahead of or behind the RF electrode 50, the first waveguide arm 10 and the second waveguide arm 20 overlap with the electrodes in the RF electrode 50 in the turning region ST.
[0075] This disclosure also provides an electro-optic modulator, including the folded Mach-Zehnder modulation device 100 described in the above embodiments.
[0076] In summary, the folded Mach-Zehnder modulator provided in this disclosure can significantly reduce the length dimension while meeting device performance requirements, achieving miniaturized device design and making it easier to integrate into a hardware system. The first and second waveguide arms are arranged sequentially without crossing in the turning region, avoiding losses and crosstalk caused by waveguide crossings. A turning region is provided between the first and second modulation regions. By configuring the bending rates of the waveguide arms and strip electrodes, the transmission distance of the optical and radio frequency signals can be adjusted, thereby achieving secondary group velocity matching between the optical and radio frequency signals. This ensures a stable phase relationship between the modulated signal and the optical wave within the modulation region, improving modulation bandwidth and modulation efficiency.
[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and not to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure, and they should all be covered within the scope of the claims and specification of this disclosure. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. This disclosure is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
Claims
1. A folded Mach-Zehnder modulation device, comprising a first modulation region, a turning region, and a second modulation region extending sequentially along the optical signal transmission direction, wherein the turning region connects the first modulation region and the second modulation region, the folded Mach-Zehnder modulation device comprising: First waveguide arm and second waveguide arm, the first waveguide arm and the second waveguide arm are folded in a general shape and are arranged in sequence without crossing in the turning area, the first waveguide arm and the second waveguide arm have optical signal modulation section; as well as The radio frequency (RF) electrode comprises a plurality of strip-shaped electrodes arranged sequentially in a folded, non-intersecting manner, configured to apply an RF voltage to the first waveguide arm and / or the second waveguide arm; wherein, Along the optical signal transmission direction, the optical signal modulation section sequentially includes a basic modulation section, an in-phase modulation section, and an out-of-phase modulation section. The basic modulation section is located in the first modulation region, and the out-of-phase modulation section is located in the second modulation region. The first waveguide arm and the second waveguide arm generate a certain phase difference in the basic modulation section. The first waveguide arm and the second waveguide arm generate a phase difference in the in-phase modulation section that is in phase with the phase difference generated in the basic modulation section. The first waveguide arm and the second waveguide arm generate a phase difference in the out-of-phase modulation section that is out of phase with the phase difference generated in the basic modulation section.
2. The folded Mach-Zehnder modulating device according to claim 1, wherein The in-phase modulation segment and the out-of-phase modulation segment have equal lengths.
3. The folded Mach-Zehnder modulating device according to claim 1, wherein The radio frequency electrodes include: an outer ground electrode, a negative signal electrode, a middle ground electrode, a positive signal electrode, and an inner ground electrode arranged in sequence without crossing.
4. The folded Mach-Zehnder modulating device according to claim 3, wherein The radio frequency electrode includes a first spacing group and a second spacing group among a plurality of strip electrodes, either adjacent or spaced apart from each other. In a direction perpendicular to the optical signal transmission direction, the first spacing group includes a first spacing located above the positive signal electrode and below the negative signal electrode, and the second spacing group includes a second spacing located below the positive signal electrode and above the negative signal electrode. In the basic modulation segment and the in-phase modulation segment, the first waveguide arm is arranged in any first interval of the first interval group, and the second waveguide arm is arranged in any second interval of the second interval group; and in the out-of-phase modulation segment, the first waveguide arm is arranged in any second interval of the second interval group, and the second waveguide arm is arranged in any first interval of the first interval group.
5. The folded Mach-Zehnder modulating device according to claim 4, wherein The in-phase modulation section is located in the second modulation region, such that the optical signal enters the in-phase modulation section from the basic modulation section via the turning region, and then enters the out-of-phase modulation section.
6. The folded Mach-Zehnder modulating device according to claim 4, wherein The in-phase modulation section is located in the first modulation region, such that the optical signal enters the in-phase modulation section from the basic modulation section and then enters the out-of-phase modulation section via the turning region.
7. The folded Mach-Zehnder modulating device according to claim 3, wherein The first waveguide arm and the second waveguide arm turn synchronously with the turning of the radio frequency electrode; or the first waveguide arm and the second waveguide arm lag behind the turning of the radio frequency electrode; or the first waveguide arm and the second waveguide arm lead the turning of the radio frequency electrode.
8. The folded Mach-Zehnder modulating device according to claim 1, wherein The folded Mach-Zehnder modulation device further includes: a beam splitter for splitting the input optical signal into two paths and then feeding them into the first waveguide arm and the second waveguide arm respectively; and a beam combiner for combining the two optical signals from the first waveguide arm and the second waveguide arm and then outputting them.
9. The folded Mach-Zehnder modulating device according to claim 1, wherein The folded Mach-Zehnder modulation device includes a substrate, an isolation layer, a waveguide layer, an electrode layer, and an insulating material layer arranged sequentially. The first waveguide arm and the second waveguide arm are located in the waveguide layer, and the radio frequency electrode is located in the electrode layer. In a projection in a direction perpendicular to the substrate, the first waveguide arm and the second waveguide arm overlap with the electrode in the radio frequency electrode in the turning region, or the first waveguide arm and the second waveguide arm overlap with the radio frequency electrode in the region between the in-phase modulation segment and the out-of-phase modulation segment.
10. An electro-optic modulator, characterized by The electro-optic modulator includes a folded Mach-Zehnder modulation device according to any one of claims 1 to 9.