Phase shifter, optical device, modulator, and optical apparatus

Abstract

The embodiment of the invention provides a phase shifter, an optical device, a modulator and optical equipment, and relates to the technical field of optical communication, and the phase shifter is simple in structure, has non-volatility, and is not sensitive to polarization. The phase shifter comprises a lower wrapping layer, a waveguide layer and an upper wrapping layer covering the waveguide layer and the lower wrapping layer which are sequentially arranged in the stacking direction. The phase-change material layer is arranged between the waveguide layer and the upper cladding; when the first optical signal and the second optical signal input to the phase shifter are equal in phase and the crystallinity of the phase change material layer is a set value, the phase difference between the first optical signal and the second optical signal output by the phase shifter is less than or equal to 1 degree / micron; wherein the polarization direction of the first optical signal is a first polarization direction, the polarization direction of the second optical signal is a second polarization direction, and the first polarization direction is different from the second polarization direction.

Description

Technical Field

[0001] This application relates to the field of optical communication technology, and in particular to a phase shifter, optical device, modulator and optical equipment. Background Technology

[0002] Due to the demands for transmission rate, capacity, and miniaturization in fiber optic communication systems, optical signal processing devices have evolved from spatial optical paths to waveguide optical paths. Because of the inherent properties of the materials, the waveguide cross-section of some optical signal processing devices is rectangular. For example, silicon-based single-mode waveguides typically have a width of 500 nanometers and a height of 220 nanometers. Such silicon-based single-mode waveguides are polarization-sensitive, therefore, polarization dependence is often introduced into optical signal processing devices based on silicon-based single-mode waveguides. The output performance of the horizontally polarized portion of the optical signal from the optical signal processing device differs from that of the vertically polarized portion.

[0003] To avoid the adverse effects of polarization dependence, an increasing number of optical signal processing devices are opting for polarization-splitting processing. Taking a polarization-splitting phase shifter as an example, the phase shifter requires a polarization beam splitter to divide the incident optical signal into a first part with horizontal polarization (TE) and a second part with vertical polarization (TM). The phase shifter also needs two different sub-phase shifters to shift the first and second parts of the optical signal respectively. Finally, a polarization beam combiner is required to combine the phase-shifted first and second parts of the optical signal. As can be seen, polarization-splitting phase shifters have complex structures and introduce additional insertion losses. Summary of the Invention

[0004] Embodiments of this application provide a phase shifter, an optical device, a modulator, and an optical apparatus. The phase shifter has a simple structure, is non-volatile, and is polarization insensitive.

[0005] In a first aspect, a phase shifter is provided, comprising: a lower cladding layer, a waveguide layer, and an upper cladding layer arranged sequentially along a stacking direction; the phase shifter further comprises: a phase change material layer disposed between the waveguide layer and the upper cladding layer; when the phases of a first optical signal and a second optical signal input to the phase shifter are equal, and the crystallinity of the phase change material layer is a set value, the phase difference between the first optical signal and the second optical signal output by the phase shifter is less than or equal to 1 degree / micrometer; wherein, the polarization direction of the first optical signal is a first polarization direction, the polarization direction of the second optical signal is a second polarization direction, and the first polarization direction and the second polarization direction are different. In this phase shifter, since the first and second optical signals input to the phase shifter are in phase, and the crystallinity of the phase change material layer is a set value, the phase difference between the first and second optical signals output by the phase shifter is less than or equal to 1 degree / micrometer. The polarization direction of the first optical signal is the first polarization direction, and the polarization direction of the second optical signal is the second polarization direction. Since the first and second polarization directions are different, this phase shifter is a polarization-independent phase shifter, requiring no polarization separation processing, and the introduced polarization loss is negligible; that is, this phase shifter does not introduce additional insertion loss. Furthermore, this phase shifter includes a lower cladding layer, a waveguide layer, an upper cladding layer covering the waveguide layer and the lower cladding layer, and a phase change material layer disposed between the waveguide layer and the upper cladding layer. The structure of this phase shifter is simpler than that of a phase shifter requiring polarization separation processing. Furthermore, the phase shifter includes a phase change material layer. Adjusting the crystallinity of the phase change material layer can achieve phase shifting of the first or second optical signal. The change in crystallinity of the phase change material layer is non-volatile, therefore the phase shifter is also non-volatile.

[0006] Optionally, the phase change material layer includes a first layer structure; the first layer structure is located on the side of the waveguide layer away from the lower cladding.

[0007] Optionally, the dimension of the first layer structure along the first direction is greater than 0 and less than or equal to the dimension of the waveguide layer along the first direction; the first direction is perpendicular to the optical transmission direction and perpendicular to the stacking direction of the phase shifter; the dimension of the first layer structure along the stacking direction is greater than 1 nanometer.

[0008] Optionally, the dimension of the first layer structure along the first direction is greater than 0 and smaller than the dimension of the waveguide layer along the first direction, and the center of the first layer structure along the first direction and the center of the waveguide layer along the first direction are located at the same position in the first direction.

[0009] Optionally, the side of the waveguide layer near the first layer structure is planar, and the side of the first layer structure near the waveguide layer is planar; or, the side of the waveguide layer near the first layer structure includes at least one first recess, and the side of the first layer structure near the waveguide layer includes at least one first protrusion, with at least one first recess corresponding to at least one first protrusion; or, the side of the waveguide layer near the first layer structure includes at least one second protrusion, and the side of the first layer structure near the waveguide layer includes at least one second recess, with at least one second recess corresponding to at least one second protrusion.

[0010] Optionally, the phase change material layer includes a second layer structure and a third layer structure; the second layer structure is disposed on the first side of the waveguide layer along the first direction, and the third layer structure is disposed on the second side of the waveguide layer along the first direction; the first direction is perpendicular to the optical transmission direction and perpendicular to the stacking direction of the phase shifter.

[0011] Optionally, the dimension of the second layer structure along the stacking direction is greater than 0, less than or equal to the sum of the dimension of the waveguide layer along the stacking direction and a first threshold. Wherein, if the phase change material layer does not include the first layer structure, the first threshold is 0; if the phase change material layer includes the first layer structure, the first threshold is the dimension of the first layer structure along the stacking direction. The dimension of the second layer structure along the first direction is greater than 1 nanometer. The dimension of the third layer structure along the stacking direction is equal to the dimension of the second layer along the stacking direction, and the dimension of the third layer structure along the first direction is equal to the dimension of the second layer along the first direction.

[0012] Optionally, the dimension of the second layer structure along the stacking direction is smaller than the sum of the dimension of the waveguide layer along the stacking direction and the first threshold. The second layer structure is separated from the side of the waveguide layer near the lower cladding by a first target distance, and the third layer structure is separated from the side of the waveguide layer near the lower cladding by a first target distance. The first target distance is greater than or equal to 0.

[0013] Optionally, the phase shifter may also include an electrode layer disposed on the side of the upper cladding away from the waveguide layer; the electrode layer is used to adjust the crystallinity of the phase change material layer.

[0014] Optionally, the phase change material layer includes multiple substructures arranged sequentially along the light transmission direction, and the electrode layer includes multiple sub-electrodes arranged sequentially along the light transmission direction; one sub-electrode is used to adjust the crystallinity of one substructure.

[0015] Optionally, the dimension L of the phase change material layer along the light transmission direction satisfies the following relationship: Where λ is the wavelength of the first or second optical signal, and Δn eff This represents the effective refractive index difference across the cross-section of the phase shifter when the phase change material layer switches between two different crystallinities. This refers to the phase change of the first or second optical signal output by the phase shifter when the phase change material layer switches between two different crystallinities.

[0016] Optionally, the phase change material layer may include one or more of the following: chalcogenide phase change materials (such as antimony selenide, antimony trisulfide, antimony telluride, germanium germanium, antimony selenide telluride, etc.), vanadium dioxide, organic phase change materials, etc., which are materials whose refractive index changes due to phase change induced by stimuli such as light, heat, sound, and electricity.

[0017] Optionally, the phase shifter further includes a protective layer disposed between the phase change material layer and the upper cladding layer, the protective layer being used to restrict the flow of the phase change material layer.

[0018] Optionally, the phase change material layer further includes a thermally conductive layer disposed between the electrode layer and the upper cladding layer.

[0019] Optionally, the dimension of the lower cladding layer along the stacking direction is greater than or equal to 0.3 micrometers.

[0020] Optionally, the dimension of the upper cladding layer along the stacking direction is greater than or equal to 0.01 micrometers.

[0021] Optionally, the electrode layer may be made of one or more of the following materials: titanium, gold, platinum, chromium, or tungsten.

[0022] In a second aspect, an optical device is provided, comprising: a first beam splitter, a second beam splitter, and at least one phase shifter, wherein the at least one phase shifter is connected between the first beam splitter and the second beam splitter; the phase shifter is the phase shifter described in any one of the first aspects above.

[0023] In a first optional example, at least one phase shifter includes a first phase shifter and a first beam splitter, configured to receive a first transmitted optical signal, transmit a first portion of the first transmitted optical signal to the first phase shifter, and transmit a second portion of the first transmitted optical signal to the second beam splitter; the first phase shifter is configured to shift the phase of the first portion of the optical signal; and the second beam splitter is configured to output the first transmitted optical signal when the phase difference between the first portion of the optical signal and the second portion of the optical signal is 0, and not output the first transmitted optical signal when the phase difference between the first portion of the optical signal and the second portion of the optical signal is π.

[0024] In some examples, at least one phase shifter further includes a second phase shifter, wherein the first phase shifter is connected between a first output of the first beam splitter and a first input of the second beam splitter; the second phase shifter is connected between a second output of the first beam splitter and a second input of the second beam splitter; the first beam splitter is specifically used to transmit a second portion of the optical signal in the first transmitted optical signal to the second phase shifter; the second phase shifter is used to shift the phase of the second portion of the optical signal.

[0025] In a second optional example, at least one phase shifter includes a first phase shifter and a first beam splitter, configured to receive a second transmitted optical signal through a third input terminal of the first beam splitter, transmit a first portion of the second transmitted optical signal to the first phase shifter, and transmit a second portion of the second transmitted optical signal to the second beam splitter; the first phase shifter is configured to shift the phase of the first portion of the optical signal; the second beam splitter is configured to output the second transmitted optical signal through a fourth output terminal of the second beam splitter when the phase difference between the first portion of the optical signal and the second portion of the optical signal is 0, and to output the second transmitted optical signal through a third output terminal of the second beam splitter when the phase difference between the first portion of the optical signal and the second portion of the optical signal is π, wherein the third input terminal of the first beam splitter and the fourth output terminal of the second beam splitter are centrally symmetrical.

[0026] In some examples, at least one phase shifter further includes a second phase shifter, wherein the first phase shifter is connected between a first output of the first beam splitter and a first input of the second beam splitter; the second phase shifter is connected between a second output of the first beam splitter and a second input of the second beam splitter; the first beam splitter is specifically used to transmit a second portion of the optical signal in the first transmitted optical signal to the second phase shifter; the second phase shifter is used to shift the phase of the second portion of the optical signal.

[0027] In a third alternative example, at least one phase shifter includes a first phase shifter and a first beam splitter, for receiving a carrier optical signal, transmitting a first portion of the carrier optical signal to the first phase shifter, and transmitting a second portion of the carrier optical signal to the second beam splitter; the first phase shifter is used to shift the phase of the first portion of the carrier optical signal according to an electrical signal and output a first portion of the modulated optical signal; the second beam splitter is used to interfere with the first portion of the modulated optical signal and the second portion of the optical signal to output a modulated optical signal.

[0028] In some examples, at least one phase shifter further includes a second phase shifter, wherein the first phase shifter is connected between the first output terminal of the first beam splitter and the first input terminal of the second beam splitter; the second phase shifter is connected between the second output terminal of the first beam splitter and the second input terminal of the second beam splitter; the first beam splitter is specifically used to transmit a second portion of the carrier optical signal in the carrier optical signal to the second phase shifter; the second phase shifter is used to shift the phase of the second portion of the carrier optical signal according to the electrical signal, and output a second portion of the modulated optical signal; the second beam splitter is specifically used to interfere with the first portion of the modulated optical signal and the second portion of the modulated optical signal to output a modulated optical signal.

[0029] Thirdly, a modulator is provided, comprising: a first input / output waveguide, a ring waveguide, and at least one phase shifter disposed on the ring waveguide; the first input / output waveguide is coupled to the ring waveguide; the phase shifter is the phase shifter described in any one of the first aspects above.

[0030] Optionally, the modulator may also include a second input / output waveguide; the second input / output waveguide is coupled to a ring waveguide.

[0031] Fourthly, an optical device is provided, including a light source and an optical component as described in the third optional example of the second aspect above, wherein the light source is used to output a carrier optical signal to the optical component.

[0032] Fifthly, an optical device is provided, including a light source and a modulator as described in any of the third aspects above, wherein the light source is used to output a carrier optical signal to the modulator.

[0033] In a sixth aspect, an optical device is provided, including a detection device and an optical device as described in the second optional example of the second aspect above, wherein a third output terminal of a second beam splitter in the optical device is connected to the detection device; the optical device is used to transmit an optical signal received at a third input terminal of a first beam splitter to the detection device, or to transmit an optical signal received at a fourth input terminal of the first beam splitter to the detection device; the detection device is used to detect parameters of the received optical signal.

[0034] The technical effects of any of the possible implementations of aspects two through six can be found in the technical effects of different implementations of aspect one above, and will not be repeated here. Attached Figure Description

[0035] Figure 1 A schematic diagram of the phase shifter provided in this application;

[0036] Figure 2 A three-dimensional structural schematic diagram of a phase shifter provided for an embodiment of this application;

[0037] Figure 3 for Figure 2 Cross-sectional view along AA';

[0038] Figure 4 A schematic cross-sectional view of the waveguide layer and phase change material layer provided for embodiments of this application;

[0039] Figure 5 An optical field distribution diagram of the optical signal output by the phase shifter provided in an embodiment of this application;

[0040] Figure 6 A three-dimensional structural schematic diagram of a phase shifter provided for another embodiment of this application;

[0041] Figure 7 A schematic cross-sectional view of a phase shifter provided for yet another embodiment of this application;

[0042] Figure 8 A schematic diagram of the structure of an optical device provided for an embodiment of this application;

[0043] Figure 9 A schematic diagram of the structure of an optical device provided in another embodiment of this application;

[0044] Figure 10 for Figure 9 The diagram shows the optical field transmission distribution of the optical device.

[0045] Figure 11 for Figure 9 The graph shows the relationship between the insertion loss of the optical device and the wavelength of the optical signal.

[0046] Figure 12 A schematic diagram of the structure of an optical device provided in another embodiment of this application;

[0047] Figure 13 A schematic diagram of the modulator structure provided for an embodiment of this application;

[0048] Figure 14 A schematic diagram of the structure of an optical device provided for an embodiment of this application;

[0049] Figure 15 A schematic diagram of the structure of an optical device provided in another embodiment of this application;

[0050] Figure 16 This is a schematic diagram of the structure of an optical device provided in another embodiment of this application. Detailed Implementation

[0051] The technical solutions in the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0052] Unless otherwise defined, all technical terms used herein have the same meaning as those known to one of ordinary skill in the art. In the embodiments of this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, a and b, a and c, b and c, or a, b, and c, where a, b, and c can be single or multiple. In addition, in the embodiments of this application, the words "first," "second," etc., do not limit the quantity or order.

[0053] Furthermore, in the embodiments of this application, directional terms such as "upper" and "lower" are defined relative to the orientation in which the components are schematically placed in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and can change accordingly depending on the orientation in which the components are placed in the accompanying drawings.

[0054] In the embodiments of this application, the words "exemplary" or "for example" are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Specifically, the use of the words "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0055] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0056] Due to the demands for transmission rate, capacity, and miniaturization in fiber optic communication systems, optical signal processing devices have evolved from spatial optical paths to waveguide optical paths. Because of the inherent properties of the materials, the waveguide cross-section of some optical signal processing devices is rectangular. For example, silicon-based single-mode waveguides typically have a width of 500 nanometers and a height of 220 nanometers. Such silicon-based single-mode waveguides are polarization-sensitive, therefore, optical signal processing devices based on silicon-based single-mode waveguides introduce polarization dependence. The output performance of horizontally polarized optical signals differs from that of vertically polarized optical signals.

[0057] To avoid the adverse effects of polarization dependence, an increasing number of optical signal processing devices are opting for polarization-splitting processing. Taking a polarization-splitting phase shifter as an example, the phase shifter requires a polarization beam splitter to divide the incident optical signal into a first part with horizontal polarization (TE) and a second part with vertical polarization (TM). The phase shifter also needs two different sub-phase shifters to shift the first and second parts of the optical signal respectively. Finally, a polarization beam combiner is required to combine the phase-shifted first and second parts of the optical signal. As can be seen, polarization-splitting phase shifters have complex structures and introduce additional insertion losses.

[0058] In addition, existing phase shifters typically use carrier injection and depletion methods, lithium niobate electro-optical effects, thermo-optical effects, or magneto-optical effects to achieve phase shifting. These methods usually require constant power input, which increases the energy consumption of the phase shifter and makes it volatile, meaning that the phase shifting effect will disappear when the constant power input stops.

[0059] In order to design non-volatile phase shifters, those skilled in the art have begun to focus on phase shifters based on phase change materials. Among them, the refractive index difference between the crystalline and amorphous states of phase change materials is large, and some phase change materials have relatively small absorption losses. Phase shifters based on these phase change materials achieve phase adjustment of the optical signal by adjusting the crystallinity of the phase change material, i.e., phase shifting.

[0060] Reference Figure 1 As shown in the diagram, an embodiment of this application provides a schematic structural diagram of a phase shifter 10 based on a phase change material. The phase shifter 10 includes a substrate layer 11, a waveguide layer 12 disposed on the substrate layer 11, and a phase change material layer 13 disposed on the waveguide layer 12. Wherein, Figure 1 The x-axis shown represents the stacking direction of the material layers, and the z-axis represents the optical transmission direction of the optical signal in the waveguide layer 12. The dimension of the waveguide layer 12 along the y-axis is smaller than the dimension of the substrate layer 11 along the y-axis. The dimension of the waveguide layer 12 along the y-axis is used to limit the dimension of the optical signal transmitted in the waveguide layer 12 along the y-axis. In other embodiments, a portion of the waveguide layer 12 has the same dimension along the y-axis as the substrate layer 11, and the waveguide layer 12 includes a ridge pattern for transmitting optical signals.

[0061] exist Figure 1 In the phase shifter 10 shown, the phase of the optical signal incident on the waveguide layer 12 is φ0. By adjusting the crystallinity of the phase change material layer 13, the phase of the optical signal output through the waveguide layer 12 is made to be φ0+φ1, thereby realizing the phase shifting function.

[0062] In some embodiments, refer to Figure 1 As shown, the phase shifter 10 also includes a capping layer 14 covering the substrate layer 11, the waveguide layer 12, and the phase change material layer 13. The refractive index of the capping layer 14 is lower than that of the phase change material layer 13, and the capping layer 14 is used to limit the changes in the phase change material layer 13.

[0063] in, Figure 1 The phase shifter 10 shown is designed solely to be non-volatile, without addressing how to design a polarization-independent phase shifter. According to existing technology, phase shifters based on phase change materials typically require polarization separation to achieve non-volatility and polarization independence.

[0064] Therefore, embodiments of this application provide a phase shifter based on a phase change material, which has a simple structure, is non-volatile, and is insensitive to polarization.

[0065] For example, Figure 2A three-dimensional structural schematic diagram of the phase shifter 20 provided for an embodiment of this application. Figure 3 for Figure 2 A cross-sectional view along AA', where, Figure 3 Also known as a cross-sectional diagram. Figure 2 and Figure 3 In the diagram, the x-axis is the stacking direction of the material layers, the z-axis is the light transmission direction, the y-axis is the first direction, the y-axis is perpendicular to the x-axis and the z-axis, the dimension in the y-axis direction is usually called the width, and the dimension in the x-axis direction is usually called the height.

[0066] Reference Figure 2 and Figure 3 As shown, the phase shifter 20 includes a lower cladding layer 21, a waveguide layer 22, and an upper cladding layer 23, which are sequentially arranged along the stacking direction. For example, the refractive index of the lower cladding layer 21 is less than that of the waveguide layer 22, and the refractive index of the upper cladding layer 23 is less than that of the waveguide layer 22. For instance, the lower cladding layer 21 and the upper cladding layer 23 can be made of the same material with the same refractive index. The lower cladding layer 21 and the upper cladding layer 23 are used to confine the optical signal received by the phase shifter 20 within the waveguide layer 22 for continuous reflection and transmission along the z-axis. In some embodiments, the lower cladding layer 21 and the upper cladding layer 23 are collectively referred to as cladding layers, and the waveguide layer 22 is referred to as the core layer.

[0067] Figure 2 and Figure 3 The upper cladding 23 shown covers both the waveguide layer 22 and the lower cladding 21. In some embodiments, the upper cladding 23 may also cover a portion of the waveguide layer 22.

[0068] in, Figure 2 and Figure 3 The phase shifter 20 shown also includes a phase change material layer 24 disposed between the waveguide layer 22 and the upper cladding layer 23.

[0069] exist Figure 2 and Figure 3In the phase shifter 20 shown, when the first optical signal and the second optical signal input to the phase shifter 20 are in phase, and the crystallinity of the phase change material layer 24 is a set value, the phase difference between the first optical signal and the second optical signal output by the phase shifter 20 is less than or equal to 1 degree / micrometer; wherein, the polarization direction of the first optical signal is the first polarization direction, the polarization direction of the second optical signal is the second polarization direction, and the first polarization direction and the second polarization direction are different. For example, the first polarization direction is horizontal polarization TE, and the second polarization direction is vertical polarization TM. Therefore, the phase shifter 20 is a polarization-independent phase shifter, does not require polarization separation processing, and the introduced polarization loss is negligible; that is, the phase shifter 20 does not introduce additional insertion loss. Secondly, the phase shifter 20 includes a lower cladding layer 21, a waveguide layer 22, an upper cladding layer 23 covering the waveguide layer 22 and the lower cladding layer 21, and a phase change material layer 24 disposed between the waveguide layer 22 and the upper cladding layer 23. This phase shifter 20 has a simpler structure compared to phase shifters that perform polarization separation. Thirdly, the phase shifter 20 includes a phase change material layer 24. Adjusting the crystallinity of the phase change material layer 24 can achieve phase shifting of either the first or second optical signal. Since the change in crystallinity of the phase change material layer 24 is non-volatile, the phase shifter 20 also possesses non-volatility.

[0070] For example, refer to Figure 4 As shown, embodiments of this application provide cross-sectional schematic diagrams of the waveguide layer 22 and the phase change material layer 24. Figure 4 In the waveguide layer 22, the phase change material layer 24 includes a first layer structure 241; the first layer structure 241 is located on the side of the waveguide layer 22 away from the lower cladding layer 21; or, the phase change material layer 24 includes a second layer structure 242 and a third layer structure 243; the second layer structure 242 is disposed on the first side of the waveguide layer 22 along the y-axis direction, and the third layer structure 243 is disposed on the second side of the waveguide layer 22 along the y-axis direction; or, the phase change material layer 24 includes a first layer structure 241, a second layer structure 242 and a third layer structure 243; the second layer structure 242 is disposed on the first side of the waveguide layer 22 along the y-axis direction, and the third layer structure 243 is disposed on the second side of the waveguide layer 22 along the y-axis direction.

[0071] In this structure, the dimension of the first layer 241 along the y-axis is greater than 0 and less than or equal to the dimension of the waveguide layer 22 along the y-axis. (Refer to...) Figure 4 As shown in (a), the dimension c of the first layer structure 241 along the y-axis is equal to the dimension b of the waveguide layer 22 along the y-axis. (Refer to...) Figure 4As shown in (b), the dimension c of the first layer structure 241 along the y-axis is smaller than the dimension b of the waveguide layer 22 along the y-axis, and the center of the first layer structure 241 along the y-axis and the center of the waveguide layer 22 along the y-axis are located at the same position along the y-axis. In other embodiments, when the dimension c of the first layer structure 241 along the y-axis is smaller than the dimension b of the waveguide layer 22 along the y-axis, the center of the first layer structure 241 along the y-axis and the center of the waveguide layer 22 along the y-axis are located at different positions along the y-axis.

[0072] For example, Figure 4 (a) and Figure 4 In (b) shown, the side of waveguide layer 22 closest to the first layer structure 241 is planar, and the side of the first layer structure 241 closest to the waveguide layer 22 is planar. Figure 4 As shown in (c), the waveguide layer 22 near the first layer structure 241 includes a first recess, and the first layer structure 241 near the waveguide layer 22 includes a first protrusion, with the first recess corresponding to the first protrusion. In some embodiments, the waveguide layer 22 near the first layer structure 241 includes two or more first recesses, and the first layer structure 241 near the waveguide layer 22 includes two or more first protrusions, with the two or more first recesses corresponding to the two or more first protrusions one-to-one. Figure 4 As shown in (d), the waveguide layer 22 near the first layer structure 241 includes a second protrusion, and the first layer structure 241 near the waveguide layer 22 includes a second recess, with the second recess corresponding to the second protrusion. In some embodiments, the waveguide layer 22 near the first layer structure 241 includes two or more second protrusions, and the first layer structure 241 near the waveguide layer 22 includes two or more second recesses, with the two or more second recesses corresponding to the two or more second protrusions one-to-one.

[0073] Among them, Figure 4 (a) Figure 4 (b) Figure 4 (c) and Figure 4 In (d), the dimension of the first layer structure 241 along the x-axis is d, and the dimension of the first layer structure 241 along the x-axis is the distance between the top of the waveguide layer 22 and the top of the first layer structure 241. The dimension of the first layer structure 241 along the x-axis is greater than 1 nanometer.

[0074] In some embodiments, refer to Figure 4 (e) and Figure 4 As shown in (f), the phase change material layer 24 includes a second layer structure 242 and a third layer structure 243; refer to Figure 4 (e) in Figure 4 The placement of (f) in the diagram is such that the second layer structure 242 is positioned to the right of the waveguide layer 22 along the y-axis, and the third layer structure 243 is positioned to the left of the waveguide layer 22 along the y-axis.

[0075] Wherein, the dimension e of the second layer structure 242 along the x-axis is greater than 0, and less than or equal to the sum of the dimension b of the waveguide layer 22 along the x-axis and the first threshold, wherein, Figure 4 (e) and Figure 4 The phase change material layer 24 shown in (f) does not include the first layer structure 241, therefore the first threshold is 0, meaning the dimension e of the second layer structure 242 along the x-axis is greater than 0 and less than or equal to the dimension b of the waveguide layer 22 along the x-axis. The dimension g of the second layer structure 242 along the y-axis is greater than 1 nanometer. Figure 4 As shown in (e), the dimension e of the second layer structure 242 along the x-axis is equal to the dimension b of the waveguide layer 22 along the x-axis; as Figure 4 As shown in (f), the dimension e of the second layer structure 242 along the x-axis is smaller than the dimension b of the waveguide layer 22 along the x-axis.

[0076] The dimension of the third layer structure 243 along the x-axis is equal to the dimension of the second layer structure 242 along the x-axis, and the dimension of the third layer structure 243 along the y-axis is equal to the dimension of the second layer structure 242 along the y-axis.

[0077] For example, refer to Figure 4 As shown in (f), when the dimension e of the second layer structure 242 along the x-axis is smaller than the dimension b of the waveguide layer 22 along the x-axis, the side of the second layer structure 242 near the lower cladding layer 21 is separated from the side of the waveguide layer 22 near the lower cladding layer 21 by a first target distance f, and the side of the third layer structure 243 near the lower cladding layer 21 is separated from the side of the waveguide layer 22 near the lower cladding layer 21 by a first target distance f, where the first target distance f is greater than 0. Wherein, when the first target distance f is 0, it means that the side of the second layer structure 242 near the lower cladding layer 21 and the side of the waveguide layer 22 near the lower cladding layer 21 are located in the same plane, and the side of the third layer structure 243 near the lower cladding layer 21 and the side of the waveguide layer 22 near the lower cladding layer 21 are located in the same plane. When the first target distance f is be, it means that the side of the second layer structure 242 away from the lower cladding layer 21 and the side of the waveguide layer 22 away from the lower cladding layer 21 are located in the same plane, and the side of the third layer structure 243 away from the lower cladding layer 21 and the side of the waveguide layer 22 away from the lower cladding layer 21 are located in the same plane. When the first target distance f is (be) / 2, it means that the center of the second layer structure 242 along the x-axis and the center of the waveguide layer 22 along the x-axis are located at the same position along the x-axis, and the center of the third layer structure 243 along the x-axis and the center of the waveguide layer 22 along the x-axis are located at the same position along the x-axis.

[0078] In some embodiments, refer to Figure 4 (g) and Figure 4 As shown in (h), the phase change material layer 24 includes not only the first layer structure 241, but also the second layer structure 242 and the third layer structure 243; refer to Figure 4 (g) in Figure 4 The placement of (h) is as follows: the second layer structure 242 is positioned to the right of the waveguide layer 22 along the y-axis, and the third layer structure 243 is positioned to the left of the waveguide layer 22 along the y-axis.

[0079] Wherein, the dimension e of the second layer structure 242 along the x-axis is greater than 0, and less than or equal to the sum of the dimension b of the waveguide layer 22 along the x-axis and the first threshold, wherein, Figure 4 (g) and Figure 4 The phase change material layer 24 shown in (h) includes a first layer structure 241. Therefore, the first threshold is the dimension d of the first layer structure 241 along the x-axis, meaning the dimension e of the second layer structure 242 along the x-axis is greater than 0 and less than or equal to the sum of the dimension b of the waveguide layer 22 along the x-axis and the dimension d of the first layer structure 241 along the x-axis. The dimension g of the second layer structure 242 along the y-axis is greater than 1 nanometer. For example... Figure 4 As shown in (g), the dimension e of the second layer structure 242 along the x-axis is equal to the sum of the dimension b of the waveguide layer 22 along the x-axis and the dimension d of the first layer structure 241 along the x-axis; as Figure 4 As shown in (h), the dimension e of the second layer structure 242 along the x-axis is greater than 0 and less than the sum of the dimension b of the waveguide layer 22 along the x-axis and the dimension d of the first layer structure 241 along the x-axis.

[0080] The dimension of the third layer structure 243 along the x-axis is equal to the dimension of the second layer structure along the x-axis, and the dimension of the third layer structure along the y-axis is equal to the dimension of the third layer structure along the y-axis.

[0081] For example, refer to Figure 4As shown in (h), when the dimension e of the second layer structure 242 along the x-axis is less than the sum of the dimension b of the waveguide layer 22 along the x-axis and the dimension d of the first layer structure 241 along the x-axis, the second layer structure 242 and the side of the waveguide layer 22 near the lower cladding layer 21 are separated by a first target distance f, and the third layer structure 243 and the side of the waveguide layer 22 near the lower cladding layer 21 are separated by a first target distance f, where the first target distance f is greater than 0. Wherein, when the first target distance f is 0, it means that the side of the second layer structure 242 near the lower cladding layer 21 and the side of the waveguide layer 22 near the lower cladding layer 21 are located in the same plane, and the side of the third layer structure 243 near the lower cladding layer 21 and the side of the waveguide layer 22 near the lower cladding layer 21 are located in the same plane. When the first target distance f is b+de, it means that the side of the second layer structure 242 away from the lower cladding layer 21 and the side of the waveguide layer 22 away from the lower cladding layer 21 are located in the same plane, and the side of the third layer structure 243 away from the lower cladding layer 21 and the side of the waveguide layer 22 away from the lower cladding layer 21 are located in the same plane. When the first target distance f is (b+de) / 2, it means that the center of the second layer structure 242 along the x-axis and the center of the waveguide layer 22 along the x-axis are located at the same position along the x-axis, and the center of the third layer structure 243 along the x-axis and the center of the waveguide layer 22 along the x-axis are located at the same position along the x-axis.

[0082] For example, Figure 4 The schematic phase change material layer 24 has many deformable structures. The purpose is to change the phase change material layer 24 so that the difference in effective refractive index between the first optical signal and the second optical signal transmitted in the phase shifter 20 satisfies the following condition: when the first optical signal and the second optical signal input to the phase shifter 20 are in phase, and the crystallinity of the phase change material layer 24 is a set value, the phase difference between the first optical signal and the second optical signal output by the phase shifter 20 is less than or equal to 1 degree / micrometer.

[0083] In the first specific example, a schematic cross-sectional view of the waveguide layer 22 and the phase change material layer 24 is shown below. Figure 3 or Figure 4As shown in (f), the upper cladding layer 23 is made of silicon dioxide (SiO2), the lower cladding layer 21 is made of silicon dioxide (SiO2), the waveguide layer 22 is made of silicon nitride (SiN), and the phase change material layer 24 is made of antimony selenide (Sb2Se3). The waveguide layer 22 has a dimension of 800 nanometers along the y-axis and a dimension of 800 nanometers along the x-axis. The phase change material layer 24 includes a first layer structure 241, a second layer structure 242, and a third layer structure 243. The first layer structure 241 has a dimension d of 8 nanometers along the x-axis and a dimension c of 800 nanometers along the y-axis. The second layer structure 242 has a dimension e of 558 nanometers along the x-axis and a dimension g of 8 nanometers along the y-axis. The second layer structure 242 is separated from the waveguide layer 22 near the lower cladding layer 21 by a first target distance f of 800 + 8 - 558 = 250 nanometers. The third layer structure 243 has a dimension e of 558 nanometers along the x-axis and a dimension g of 8 nanometers along the y-axis. The third layer structure 243 is separated from the waveguide layer 22 near the lower cladding layer 21 by a first target distance f of 800 + 8 - 558 = 250 nanometers.

[0084] The dimension L of the phase change material layer 24 along the z-axis satisfies the following relationship: λ is the wavelength of the first or second optical signal, and Δn eff The effective refractive index difference of the cross section of the phase shifter 20 when the phase change material layer 24 switches between two different crystallinities; The phase change of the first or second optical signal output by the phase shifter 20 when the phase change material layer 24 switches between two different crystallinities.

[0085] The phase shifter 20 is fabricated according to the parameters in the first specific example above. When the phase change material layer 24 in the phase shifter 20 switches between two states with crystallinity of crystalline and crystallinity of amorphous, the effective refractive index difference of the cross section corresponding to the phase shifter 20 transmitting the first optical signal is 0.000034, which is different from the effective refractive index difference of the cross section corresponding to the phase shifter 20 transmitting the second optical signal. With wavelengths of 1.55 micrometers (μm) for the first and second optical signals, and a dimension L of 1 micrometer along the z-axis for the phase change material layer 24, and the effective refractive index difference between the cross-section corresponding to the transmission of the first optical signal and the cross-section corresponding to the transmission of the second optical signal in the phase shifter 20 being 0.000034, it can be calculated using Formula 1 that, under the condition that the phases of the first and second optical signals input to the phase shifter 20 are equal and the crystallinity of the phase change material layer 24 remains unchanged, the phase difference between the first and second optical signals output by the phase shifter 20 is approximately 0.0078968 degrees / micrometer, which is less than or equal to 1 degree / micrometer.

[0086] Furthermore, in the first specific example above, the dimension L of the phase change material layer 24 along the z-axis is 54.3 micrometers. When the phase change material layer 24 switches between crystalline and amorphous states, the effective refractive index difference of the cross-section of the phase shifter 20 is approximately 0.0143. According to Formula 1, the phase change of the first or second optical signal with a wavelength of 1.55 micrometers output by such a phase shifter 20 is approximately π. For example, if the phase change material layer 24 is initially crystalline and then switches to an amorphous state, the phase change of both the first and second optical signals output before and after the switch is π. Similarly, if the phase change material layer 24 is initially amorphous and then switches to a crystalline state, the phase change of both the first and second optical signals output before and after the switch is π.

[0087] Reference Figure 5 As shown, Figure 5 This is the optical field distribution diagram of the optical signal output by the phase shifter 20 in the above example. Wherein, Figure 5 (a) shows the optical field distribution of the first optical signal in the waveguide layer 22 when the phase change material layer 24 is amorphous. Figure 5 (b) shows the optical field distribution of the second optical signal in the waveguide layer 22 when the phase change material layer 24 is amorphous. Figure 5 (a) and Figure 5 As shown in (b), when the phase change material layer 24 is amorphous, the light field distribution diagram of the first optical signal in the waveguide layer 22 is approximately the same as that of the second optical signal in the waveguide layer 22. This also confirms that when the phase change material layer 24 is amorphous, the phase difference between the first optical signal and the second optical signal output by the phase shifter 20 is less than or equal to 1 degree / micrometer. Figure 5 (c) shows the optical field distribution of the first optical signal in the waveguide layer 22 when the phase change material layer 24 is in a crystalline state. Figure 5 (d) in the diagram represents the optical field distribution of the second optical signal in the waveguide layer 22 when the phase change material layer 24 is crystalline. Figure 5 (c) and Figure 5 As shown in (d), when the phase change material layer 24 is crystalline, the light field distribution diagram of the first optical signal in the waveguide layer 22 is approximately the same as that of the second optical signal in the waveguide layer 22. This also confirms that when the phase change material layer 24 is crystalline, the phase difference between the first optical signal and the second optical signal output by the phase shifter 20 is less than or equal to 1 degree / micrometer.

[0088] In the second specific example, the cross-sectional schematic diagram of the waveguide layer 22 and the phase change material layer 24 is shown below. Figure 4As shown in (h), the upper cladding layer 23 is made of silicon dioxide (SiO2), the lower cladding layer 21 is made of silicon dioxide (SiO2), the waveguide layer 22 is made of silicon nitride (SiN), and the phase change material layer 24 is made of antimony selenide (Sb2Se3). The waveguide layer 22 has a dimension of 800 nm along the y-axis and a dimension of 1000 nm along the x-axis. The phase change material layer 24 includes a first layer structure 241, a second layer structure 242, and a third layer structure 243. The first layer structure 241 has a dimension d of 10 nanometers along the x-axis and a dimension c of 800 nanometers along the y-axis. The second layer structure 242 has a dimension e of 1010 nanometers along the x-axis and a dimension g of 10 nanometers along the y-axis. The second layer structure 242 is separated from the waveguide layer 22 near the lower cladding layer 21 by a first target distance f of 0. The third layer structure 243 has a dimension e of 1010 nanometers along the x-axis and a dimension g of 10 nanometers along the y-axis. The third layer structure 243 is separated from the waveguide layer 22 near the lower cladding layer 21 by a first target distance f of 0.

[0089] The phase shifter 20 is fabricated according to the parameters in the second specific example above. When the phase change material layer 24 in the phase shifter 20 switches between two states with crystallinity of crystalline and crystallinity of amorphous, the effective refractive index difference of the cross section corresponding to the phase shifter 20 transmitting the first optical signal is 0.018484, and the effective refractive index difference of the cross section corresponding to the phase shifter 20 transmitting the second optical signal is 0.018851. The difference between 0.018851 and 0.018484 is 0.000367. With wavelengths of 1.55 micrometers (μm) for the first and second optical signals, and a dimension L of 1 micrometer along the z-axis for the phase change material layer 24, and a difference of 0.0000367 between the effective refractive index difference of the cross-section corresponding to the transmission of the first optical signal and the effective refractive index difference of the cross-section corresponding to the transmission of the second optical signal by the phase shifter 20, it can be calculated using Formula 1 that, under the condition that the phases of the first and second optical signals input to the phase shifter 20 are equal and the crystallinity of the phase change material layer 24 remains unchanged, the phase difference between the first and second optical signals output by the phase shifter 20 is approximately 0.088 degrees / micrometer, which is less than or equal to 1 degree / micrometer.

[0090] In the third specific example, a schematic diagram of the cross-section of the waveguide layer 22 and the phase change material layer 24 is shown below. Figure 4As shown in (a), the upper cladding layer 23 is made of silicon dioxide (SiO2), the lower cladding layer 21 is made of silicon dioxide (SiO2), the waveguide layer 22 is made of silicon nitride (SiN), and the phase change material layer 24 is made of antimony selenide (Sb2Se3). The waveguide layer 22 has a dimension a along the y-axis of 800 nm and a dimension b along the x-axis of 750 nm. The phase change material layer 24 includes a first layer structure 241; the first layer structure 241 has a dimension d along the x-axis of 5 nm and a dimension c along the y-axis of 800 nm.

[0091] The phase shifter 20 is fabricated according to the parameters in the third specific example above. When the phase change material layer 24 in the phase shifter 20 switches between two states of crystallinity (crystalline and amorphous), the effective refractive index difference of the cross section corresponding to the phase shifter 20 transmitting the first optical signal is 0.0052, and the effective refractive index difference of the cross section corresponding to the phase shifter 20 transmitting the second optical signal is 0.0027. The difference between 0.0052 and 0.0027 is 0.0025. With wavelengths of 1.55 micrometers (μm) for the first and second optical signals, and a dimension L of 1 micrometer along the z-axis for the phase change material layer 24, and a difference of 0.0025 between the effective refractive index difference of the cross-section corresponding to the transmission of the first optical signal and the effective refractive index difference of the cross-section corresponding to the transmission of the second optical signal by the phase shifter 20, it can be calculated using Formula 1 that, under the condition that the phases of the first and second optical signals input to the phase shifter 20 are equal and the crystallinity of the phase change material layer 24 remains unchanged, the phase difference between the first and second optical signals output by the phase shifter 20 is approximately 0.6 degrees / micrometer, which is less than or equal to 1 degree / micrometer.

[0092] In the fourth specific example, a schematic cross-sectional view of the waveguide layer 22 and the phase change material layer 24 is shown below. Figure 4 As shown in (b), the upper cladding layer 23 is made of silicon dioxide (SiO2), the lower cladding layer 21 is made of silicon dioxide (SiO2), the waveguide layer 22 is made of silicon nitride (SiN), and the phase change material layer 24 is made of antimony selenide (Sb2Se3). The waveguide layer 22 has a dimension a along the y-axis of 800 nm and a dimension b along the x-axis of 750 nm. The phase change material layer 24 includes a first layer structure 241; the first layer structure 241 has a dimension d along the x-axis of 5 nm and a dimension c along the y-axis of 400 nm.

[0093] The phase shifter 20 is fabricated according to the parameters in the fourth specific example above. When the phase change material layer 24 in the phase shifter 20 switches between two states with crystallinity of crystalline and crystallinity of amorphous, the effective refractive index difference of the cross section corresponding to the phase shifter 20 transmitting the first optical signal is 0.00285, and the effective refractive index difference of the cross section corresponding to the phase shifter 20 transmitting the second optical signal is 0.00172. The difference between 0.00285 and 0.00172 is 0.00113. With wavelengths of 1.55 micrometers (μm) for the first and second optical signals, and a dimension L of 1 micrometer along the z-axis for the phase change material layer 24, and the effective refractive index difference between the cross-section corresponding to the transmission of the first optical signal and the cross-section corresponding to the transmission of the second optical signal in the phase shifter 20 being 0.00113, it can be calculated using Formula 1 that, under the condition that the phases of the first and second optical signals input to the phase shifter 20 are equal and the crystallinity of the phase change material layer 24 remains unchanged, the phase difference between the first and second optical signals output by the phase shifter 20 is approximately 0.2625 degrees / micrometer, which is less than or equal to 1 degree / micrometer.

[0094] In the fifth specific example, a schematic cross-sectional view of the waveguide layer 22 and the phase change material layer 24 is shown below. Figure 4 As shown in (e), the upper cladding layer 23 is made of silicon dioxide (SiO2), the lower cladding layer 21 is made of silicon dioxide (SiO2), the waveguide layer 22 is made of silicon nitride (SiN), and the phase change material layer 24 is made of antimony selenide (Sb2Se3). The waveguide layer 22 has a dimension a of 800 nm along the y-axis and a dimension b of 800 nm along the x-axis. The phase change material layer 24 includes a second layer structure 242 and a third layer structure 243; the second layer structure 242 has a dimension e of 800 nm along the x-axis and a dimension g of 5 nm along the y-axis, and the second layer structure 242 is separated from the waveguide layer 22 near the lower cladding layer 21 by a first target distance f of 0; the third layer structure 243 has a dimension e of 800 nm along the x-axis and a dimension g of 5 nm along the y-axis, and the third layer structure 243 is separated from the waveguide layer 22 near the lower cladding layer 21 by a first target distance f of 0.

[0095] The phase shifter 20 is fabricated according to the parameters in the fifth specific example above. When the phase change material layer 24 in the phase shifter 20 switches between two states with crystallinity of crystalline and crystallinity of amorphous, the effective refractive index difference of the cross section corresponding to the phase shifter 20 transmitting the first optical signal is 0.00461, and the effective refractive index difference of the cross section corresponding to the phase shifter 20 transmitting the second optical signal is 0.00855. The difference between 0.00855 and 0.00461 is 0.00394. With wavelengths of 1.55 micrometers (μm) for the first and second optical signals, and a dimension L of 1 micrometer along the z-axis for the phase change material layer 24, and the effective refractive index difference between the cross-section corresponding to the transmission of the first optical signal and the cross-section corresponding to the transmission of the second optical signal in the phase shifter 20 being 0.00394, it can be calculated using Formula 1 that, under the condition that the phases of the first and second optical signals input to the phase shifter 20 are equal and the crystallinity of the phase change material layer 24 remains unchanged, the phase difference between the first and second optical signals output by the phase shifter 20 is approximately 0.9151 degrees / micrometer, which is less than or equal to 1 degree / micrometer.

[0096] For example, refer to Figure 2 or Figure 3 As shown, the phase shifter 20 also includes an electrode layer 25 disposed on the side of the upper cladding 23 away from the waveguide layer 22. The electrode layer 25 is used to adjust the crystallinity of the phase change material layer 24.

[0097] In the first specific example described above, the phase change material layer 24 has a dimension L of 54.3 micrometers along the z-axis. When the phase change material layer 24 switches between crystalline and amorphous states, the effective refractive index difference of the cross-section of the phase shifter 20 is approximately 0.0143. According to Formula 1, the phase change of the first or second optical signal with a wavelength of 1.55 micrometers output by such a phase shifter 20 is approximately π. However, the crystallinity of the phase change material 24 can have various different crystal states, such as 10% crystalline and 90% amorphous, or 20% crystalline and 80% amorphous, or 30% crystalline and 70% amorphous, etc. In some embodiments, when the crystallinity of the phase change material layer 24 switches from amorphous to the first crystalline state, the phase change of the output first or second optical signal is... The crystallinity of the phase change material layer 24 changes from an amorphous state to a second crystalline state, and the phase change of the output first or second optical signal is: The crystallinity of the phase change material layer 24 changes from an amorphous state to a third crystalline state, and the phase change of the output first or second optical signal is: When the crystallinity of the phase change material layer 24 switches from an amorphous state to a crystalline state, the phase change of the output first or second optical signal is π. Similarly, the crystallinity of the phase change material layer 24 can switch between any two crystalline states, thus allowing the phase change of the output first or second optical signal to be any value.

[0098] In other embodiments, in order to ensure that the phase change of the first or second optical signal output by the phase shifter 20 is Reference Figure 6 As shown, the phase change material layer 24 includes multiple substructures 240 arranged sequentially along the z-axis, and the electrode layer 25 includes multiple sub-electrodes 250 arranged sequentially along the z-axis; each sub-electrode 250 is used to adjust the crystallinity of a substructure 240. Specifically, Figure 6 The phase change material layer 24 shown includes substructures 240-1, 240-2, 240-3, and 240-4 arranged sequentially along the z-axis. The electrode layer 25 includes sub-electrodes 250-1, 250-2, 250-3, and 250-4 arranged sequentially along the z-axis. Sub-electrode 250-1 is used to adjust the crystallinity of substructure 240-1; sub-electrode 250-2 is used to adjust the crystallinity of substructure 240-2; sub-electrode 250-3 is used to adjust the crystallinity of substructure 240-3; and sub-electrode 250-4 is used to adjust the crystallinity of substructure 240-3. Each of substructures 240-1, 240-2, 240-3, and 240-4 has a dimension of 13.575 micrometers along the z-axis. In summary, the crystallinity of substructure 240-1 in phase change material layer 24 changes from amorphous to crystalline, while the crystallinity of substructures 240-2, 240-3, and 240-4 remains amorphous. The phase change of the output first or second optical signal is... In the phase change material layer 24, the crystallinity of substructures 240-1 and 240-2 changes from amorphous to crystalline, while the crystallinity of substructures 240-3 and 240-4 remains amorphous. The phase change of the output first or second optical signal is... The crystallinity of substructures 240-1, 240-2, and 240-3 in the phase change material layer 24 switches from amorphous to crystalline, while the crystallinity of substructure 240-4 remains amorphous. The phase change of the output first or second optical signal is... The crystallinity of substructures 240-1, 240-2, 240-3 and 240-4 in the phase change material layer 24 changes from amorphous to crystalline, and the phase change of the output first or second optical signal is π.

[0099] exist Figure 6In the phase shifter 20 shown, the cross-sectional view of substructure 240-1 along BB' is as follows. Figure 3 or Figure 4 As shown in (f), the cross-sectional view of substructure 240-2 along CC' is as follows. Figure 3 As shown, the cross-sectional view of substructure 240-3 along DD' is as follows. Figure 3 As shown, the cross-sectional view of substructure 240-4 along EE' is as follows. Figure 3 As shown. The upper cladding layer 23 is made of silicon dioxide (SiO2), the lower cladding layer 21 is made of silicon dioxide (SiO2), the waveguide layer 22 is made of silicon nitride (SiN), and the phase change material layer 24 is made of antimony selenide (Sb2Se3). The waveguide layer 22 has a square cross-section with a cross-sectional dimension of 800 nanometers (nm). Each substructure 240 includes a first layer structure 241, a second layer structure 242, and a third layer structure 243. The first layer structure 241 has a dimension d of 8 nanometers along the x-axis and a dimension c of 800 nanometers along the y-axis. The second layer structure 242 has a dimension e of 550 nanometers along the x-axis and a dimension g of 8 nanometers along the y-axis. The second layer structure 242 is separated from the waveguide layer 22 near the lower cladding layer 21 by a first target distance f of 250 nanometers. The third layer structure 243 has a dimension e of 550 nanometers along the x-axis and a dimension g of 8 nanometers along the y-axis. The third layer structure 243 is separated from the waveguide layer 22 near the lower cladding layer 21 by a first target distance f of 250 nanometers.

[0100] Similarly, the phase change material layer 24 can include more or fewer substructures 240, and the electrode layer 25 can include more or fewer subelectrodes 250, thereby making the phase change of the output first optical signal or second optical signal arbitrary.

[0101] For example, in the above embodiments, the material of the phase change material layer 24 is antimony selenide Sb₂Se₃. The material of the phase change material layer 24 includes one or more of the following: antimony selenide Sb₂Se₃, antimony trisulfide Sb₂S₃, germanium-antimony-tellurium (GST), germanium-antimony-tellurium selenide (GSST), vanadium dioxide (VO₂), organic phase change materials, etc., which undergo refractive index changes due to phase transitions induced by stimuli such as light, heat, sound, and electricity. The molecular formulas of germanium-antimony-tellurium and germanium-antimony-tellurium selenide can be changed, and the ratio of each component can be varied according to requirements. When the material of the phase change material layer 24 is different, Δn in the above formula one... eff It will change, and then be determined according to Formula 1 above. And the specific value of L.

[0102] In some embodiments, refer to Figure 7As shown, the phase shifter 20 also includes a protective layer 26, which is disposed between the phase change material layer 24 and the upper cladding layer 23. The protective layer 26 is used to restrict the flow of the phase change material layer 24. For example, when the phase change material layer 24 is amorphous, it has fluidity, and the protective layer 26 can restrict its flow. The phase shifter 20 also includes a thermally conductive layer 27, which is disposed between the electrode layer 25 and the upper cladding layer 23. The thermally conductive layer 27 is a common material layer that increases the thermal conductivity between the electrode layer 25 and the phase change material layer 24.

[0103] For example, the lower cladding layer 21 has a dimension greater than or equal to 0.3 micrometers along the x-axis. The upper cladding layer 23 has a dimension greater than or equal to 0.01 micrometers and less than or equal to 3 micrometers along the x-axis. The electrode layer 25 is made of one or more of the following materials: titanium (Ti), gold (Au), platinum (Pt), chromium (Cr), and tungsten (W). For example, the electrode layer 25 can be made of titanium, gold, tungsten, etc., stacked together.

[0104] In some embodiments, refer to Figure 8 or Figure 9 or Figure 12 As shown, embodiments of this application also provide an optical device 30, which includes: a beam splitter 31, a beam splitter 32, and at least one phase shifter 20; the beam splitter 31 is also referred to as a first beam splitter, and the beam splitter 32 is also referred to as a second beam splitter. At least one phase shifter 20 is connected between the beam splitter 31 and the beam splitter 32. The phase shifter 20 is... Figure 2 or Figure 6 The phase shifter 20 shown.

[0105] exist Figure 8 In the example, at least one phase shifter 20 includes a phase shifter 20-1, also referred to as the first phase shifter, which is connected between the first output terminal o1 of the beam splitter 31 and the first input terminal i1 of the beam splitter 32. The second output terminal o2 of the beam splitter 31 is connected to the second input terminal i2 of the beam splitter 32. The beam splitter 31 includes an input terminal i2, and the beam splitter 32 includes an output terminal o3. In this case, the beam splitter 31 is used to receive the transmitted optical signal O1, also known as the first transmitted optical signal. It transmits the first part of the transmitted optical signal O1, O11, to the phase shifter 20-1 and the second part of the transmitted optical signal O1, O12, to the beam splitter 32. The phase shifter 20-1 is used to shift the phase of the first part of the optical signal O11. The beam splitter 32 is used to output the transmitted optical signal O1 when the phase difference between the first part of the optical signal O11 and the second part of the optical signal O12 is 0, and not output the transmitted optical signal O1 when the phase difference between the first part of the optical signal O11 and the second part of the optical signal O12 is π.

[0106] in, Figure 8 The optical device shown can specifically be a 1*1 optical switch, where the phase change of the first part of the optical signal O11 output by the phase shifter 20-1 is either 0 or π. For example, if the phase change of the first part of the optical signal O11 output by the phase shifter 20-1 is 0, the beam splitter 32 outputs the transmission optical signal O1 based on the phase difference between the first part of the optical signal O11 and the second part of the optical signal O12 being 0, and the optical switch is turned on; if the phase change of the first part of the optical signal O11 output by the phase shifter 20-1 is π, the beam splitter 32 does not output the transmission optical signal O1 based on the phase difference between the first part of the optical signal O11 and the second part of the optical signal O12 being π, and the optical switch is turned off.

[0107] In some embodiments, refer to Figure 8 As shown, at least one phase shifter also includes a phase shifter 20-2, also referred to as the second phase shifter. The phase shifter 20-2 is connected between the second output terminal o2 of the beam splitter 31 and the second input terminal i2 of the beam splitter 32. The beam splitter 31 transmits the first part of the transmitted optical signal O11 to the phase shifter 20-1 and the second part of the transmitted optical signal O12 to the phase shifter 20-2. The phase shifter 20-1 is used to shift the phase of the first part of the optical signal O11; the phase shifter 20-2 is used to shift the phase of the second part of the optical signal O12. The beam splitter 32 is used to output the transmitted optical signal O1 when the phase difference between the first part of the optical signal O11 and the second part of the optical signal O12 is 0, and not output the transmitted optical signal O1 when the phase difference between the first part of the optical signal O11 and the second part of the optical signal O12 is π.

[0108] Furthermore, since phase shifters 20-1 and 20-2 are polarization-independent phase shifters, when beam splitters 31 and 32 are also polarization-independent beam splitters, the polarization direction of the transmitted optical signal O1, whether it is the first polarization direction or the second polarization direction, conforms to the above-mentioned output rules.

[0109] exist Figure 9 In the example, at least one phase shifter 20 includes a phase shifter 20-1, also referred to as the first phase shifter. Phase shifter 20-1 is connected between the first output terminal o1 of beam splitter 31 and the first input terminal i1 of beam splitter 32. The second output terminal o2 of beam splitter 31 is connected to the second input terminal i2 of beam splitter 32. Beam splitter 31 includes two input terminals, a third input terminal i3 and a fourth input terminal i4; beam splitter 32 includes two output terminals, a third output terminal o3 and a fourth output terminal o4. Figure 9As shown, in the optical device 30, the third input terminal i3 of the beam splitter 31 is centrally symmetrical with the fourth output terminal o4 of the beam splitter 32, and the fourth input terminal i4 of the beam splitter 31 is centrally symmetrical with the third output terminal o3 of the beam splitter 32. In this case, the beam splitter 31 is used to receive the transmitted optical signal O2 through its third input terminal i3. The transmitted optical signal O2 is also called the second transmitted optical signal. The first part of the transmitted optical signal O2, O21, is transmitted to the phase shifter 20-1, and the second part of the transmitted optical signal O2, O22, is transmitted to the beam splitter 32. The phase shifter 20-1 is used to shift the phase of the first part of the optical signal O21. The beam splitter 32 is used to output the transmitted optical signal O2 through its fourth output terminal o4 based on the phase difference between the first part of the optical signal O21 and the second part of the optical signal O22 being 0, and to output the transmitted optical signal O2 through its third output terminal o3 based on the phase difference between the first part of the optical signal O21 and the second part of the optical signal O22 being π.

[0110] Among them, the beam splitter 31 is also used to receive the transmitted optical signal O3 through the fourth input terminal i4 of the beam splitter 31. The transmitted optical signal O3 is also called the third transmitted optical signal. The first part of the transmitted optical signal O3, O31, is transmitted to the phase shifter 20-1, and the second part of the transmitted optical signal O3, O32, is transmitted to the beam splitter 32. The phase shifter 20-1 is used to shift the phase of the first part of the optical signal O31. The beam splitter 32 is used to output the transmitted optical signal O3 through the third output terminal o3 of the beam splitter 32 according to the phase difference between the first part of the optical signal O31 and the second part of the optical signal O32 being 0, and to output the transmitted optical signal O3 through the fourth output terminal o4 of the beam splitter 32 according to the phase difference between the first part of the optical signal O31 and the second part of the optical signal O32 being π.

[0111] in, Figure 9 The optical device shown can specifically be a 2*2 optical switch, where the phase change of the optical signal output by phase shifter 20-1 is either 0 or π. For example, if the phase change of the first part of the optical signal O21 output by phase shifter 20-1 is 0, the beam splitter 32 outputs the transmitted optical signal O2 through its fourth output terminal o4 based on the 0 phase difference between the first part of the optical signal O21 and the second part of the optical signal O22; if the phase change of the first part of the optical signal O21 output by phase shifter 20-1 is π, the beam splitter 32 outputs the transmitted optical signal O2 through its third output terminal o3 based on the π phase difference between the first part of the optical signal O21 and the second part of the optical signal O22.

[0112] For example, if the phase change of the first part of the optical signal O31 output by the phase shifter 20-1 is 0, the beam splitter 32 outputs the transmission optical signal O3 through its third output terminal o3 based on the phase difference between the first part of the optical signal O31 and the second part of the optical signal O32 being 0; if the phase change of the first part of the optical signal O31 output by the phase shifter 20-1 is π, the beam splitter 32 outputs the transmission optical signal O3 through its fourth output terminal o4 based on the phase difference between the first part of the optical signal O31 and the second part of the optical signal O32 being π.

[0113] In some embodiments, refer to Figure 9 As shown, at least one phase shifter also includes a phase shifter 20-2, which is also referred to as a second phase shifter. The phase shifter 20-2 is connected between the second output terminal o2 of the beam splitter 31 and the second input terminal i2 of the beam splitter 32. Optical splitter 31 receives the transmitted optical signal O2 through its third input terminal i3, transmits the first part of the transmitted optical signal O21 to phase shifter 20-1, and transmits the second part of the transmitted optical signal O22 to phase shifter 20-2; phase shifter 20-1 is used to shift the phase of the first part of the optical signal O21; phase shifter 20-2 is used to shift the phase of the second part of the optical signal O22; optical splitter 32 is used to output the transmitted optical signal O2 through its fourth output terminal o4 based on the phase difference between the first part of the optical signal O21 and the second part of the optical signal O22 being 0, and to output the transmitted optical signal O2 through its third output terminal o3 based on the phase difference between the first part of the optical signal O21 and the second part of the optical signal O22 being π.

[0114] The beam splitter 31 also receives the transmitted optical signal O3 through its fourth input terminal i4, transmits the first part of the transmitted optical signal O31 to the phase shifter 20-1, and transmits the second part of the transmitted optical signal O32 to the phase shifter 20-2; the phase shifter 20-1 is used to shift the phase of the first part of the optical signal O31; the phase shifter 20-2 is used to shift the phase of the second part of the optical signal O32; the beam splitter 32 is used to output the transmitted optical signal O3 through its third output terminal o3 according to the phase difference between the first part of the optical signal O31 and the second part of the optical signal O32 being 0, and to output the transmitted optical signal O3 through its fourth output terminal o4 according to the phase difference between the first part of the optical signal O31 and the second part of the optical signal O32 being π.

[0115] Furthermore, since phase shifters 20-1 and 20-2 are polarization-independent phase shifters, when beam splitters 31 and 32 are also polarization-independent beam splitters, the polarization direction of the transmitted optical signal O2, whether it is the first polarization direction or the second polarization direction, conforms to the above-mentioned output rules. (Refer to...) Figure 10 As shown, Figure 10 It shows Figure 9 The optical field transmission distribution diagram of the optical device 30 is shown.

[0116] Reference Figure 10 As shown in (a) in the figure, Figure 10 In the optical device 30 shown in (a), the third input terminal i3 of the beam splitter 31 receives a transmitted optical signal O2 with a first polarization direction, which is horizontally polarized TE. Figure 10 In the optical device 30 shown in (a), the phase difference between the first part of the optical signal O21 and the second part of the optical signal O22 received by the beam splitter 32 is 0. Therefore, the transmitted optical signal O2 with the polarization direction of the first polarization direction will be output through the fourth output terminal o4 of the beam splitter 32.

[0117] Reference Figure 10 As shown in (b) in the figure, Figure 10 In the optical device 30 shown in (b), the third input terminal i3 of the beam splitter 31 receives a transmitted optical signal O2 with a second polarization direction, which is vertically polarized TM. Figure 10 In (b) shown in the image, the phase difference between the first part of the optical signal O21 and the second part of the optical signal O22 received by the beam splitter 32 in the optical device 30 is 0. Therefore, the transmitted optical signal O2 with the polarization direction of the second polarization direction will be output through the fourth output terminal o4 of the beam splitter 32.

[0118] Reference Figure 10 As shown in (c) in the figure, Figure 10 In the optical device 30 shown in (c), the third input terminal of the beam splitter 31 receives a transmitted optical signal O2 with a first polarization direction, which is horizontally polarized TE. Figure 10 In the optical device 30 shown in (c), the phase difference between the first part of the optical signal O21 and the second part of the optical signal O22 received by the beam splitter 32 is π. Therefore, the transmitted optical signal O2 with the polarization direction of the first polarization direction will be output through the third output terminal o3 of the beam splitter 32.

[0119] Reference Figure 10 As shown in (d) in the figure, Figure 10 In the optical device 30 shown in (d), the third input terminal of the beam splitter 31 receives a transmitted optical signal O2 with a second polarization direction, which is vertically polarized TM. Figure 10 In the optical device 30 shown in (d), the phase difference between the first part of the optical signal O21 and the second part of the optical signal O22 received by the beam splitter 32 is π. Therefore, the transmitted optical signal O2 with the polarization direction of the second polarization direction will be output through the third output terminal o3 of the beam splitter 32.

[0120] Reference Figure 11 As shown, Figure 11 It shows Figure 9 The graph shows the relationship between the insertion loss of the optical device 30 and the wavelength of the optical signal. (Refer to...) Figure 11 As shown in (a) in the figure, Figure 11 Curve 1 in (a) represents the relationship between the insertion loss of the optical device 30 and the wavelength of the transmitted optical signal O2 when the polarization direction of the transmitted optical signal O2 is the first polarization direction, the crystallinity of phase shifter 20-1 is amorphous, the crystallinity of phase shifter 20-2 is amorphous, and the phase difference between the first part of the optical signal O21 and the second part of the optical signal O22 received by the beam splitter 32 is 0. Figure 11 Curve 2 in (a) shows the relationship between the insertion loss of the optical device 30 and the wavelength of the transmitted optical signal O2 when the polarization direction of the transmitted optical signal O2 is the first polarization direction, the crystallinity of phase shifter 20-1 is amorphous, the crystallinity of phase shifter 20-2 is crystalline, and the phase difference between the first part of the optical signal O21 and the second part of the optical signal O22 received by the beam splitter 32 is π. Figure 11 As can be seen from curves 1 and 2 in (a), changing the crystallinity of phase shifter 20 does not have a significant impact on the insertion loss of optical device 30.

[0121] Reference Figure 11 As shown in (b) in the figure, Figure 11 Curve 3 in (b) represents the relationship between the insertion loss of the optical device 30 and the wavelength of the transmitted optical signal O2, assuming the polarization direction of the transmitted optical signal O2 is the second polarization direction, the crystallinity of phase shifter 20-1 is amorphous, the crystallinity of phase shifter 20-2 is amorphous, and the phase difference between the first part of the optical signal O21 and the second part of the optical signal O22 received by the beam splitter 32 is 0. Figure 11 Curve 4 in (b) shows the relationship between the insertion loss of the optical device 30 and the wavelength of the transmitted optical signal O2 when the polarization direction of the transmitted optical signal O2 is the second polarization direction, the crystallinity of phase shifter 20-1 is amorphous, the crystallinity of phase shifter 20-2 is crystalline, and the phase difference between the first part of the optical signal O21 and the second part of the optical signal O22 received by the beam splitter 32 is π. Figure 11 As can be seen from curves three and four in (b), changing the crystallinity of the phase shifter does not have a significant impact on the insertion loss of the optical device 30.

[0122] Reference Figure 11As shown, by comparing curve 1 with curve 3 and curve 2 with curve 4, it can be seen that the polarization direction of the transmitted optical signal O2 affects the insertion loss of the optical device 30. When the wavelength of the transmitted optical signal does not change and the crystallinity of phase shifter 20-1 and phase shifter 20-2 does not change, the change in polarization direction will cause the insertion loss to change by less than 0.05dB.

[0123] For example, refer to Figure 12 As shown, Figure 12 The optical device 30 shown is specifically a Mach-Zehnder (MZ) modulator. At least one phase shifter 20 includes a phase shifter 20-1, also referred to as the first phase shifter. The phase shifter 20-1 is connected between the first output terminal o1 of the beam splitter 31 and the first input terminal i1 of the beam splitter 32. The second output terminal o2 of the beam splitter 31 is connected to the second input terminal i2 of the beam splitter 32. The phase shifter 20-1 is also referred to as the first modulation arm. The beam splitter 31 includes an input terminal i3, and the beam splitter 32 includes an output terminal o3. (Refer to...) Figure 12 As shown, beam splitter 31 receives carrier optical signal O4 through its input terminal i3, transmits the first part of carrier optical signal O41 to phase shifter 20-1, and transmits the second part of carrier optical signal O42 to beam splitter 32; phase shifter 20-1 shifts the phase of the first part of carrier optical signal O41 according to electrical signal S1, and outputs the first part of modulated optical signal O41'; beam splitter 32 interferes with the first part of modulated optical signal O41' and the second part of optical signal O42, and outputs the modulated optical signal O4' through its output terminal o3. The input to... Figure 11 The electrical signal of the optical device 30 shown carries the transmission information. The optical device 30 realizes electro-optic modulation, which ultimately makes the modulated optical signal O4' output by the optical device 30 carry the transmission information.

[0124] And in Figure 12 In the optical device 30 shown, the phase change of the first portion of the carrier optical signal O41' output by the phase shifter 20-1 includes multiple orders of magnitudes such as 0, π, and 0 to π. Specifically, the phase change of the phase shifter 20-1 can be set according to modulation requirements. In this case, the crystallinity of the phase change material layer 24 in the phase shifter 20-1 includes multiple different crystal states.

[0125] In some embodiments, refer to Figure 10As shown, at least one phase shifter also includes a phase shifter 20-2, which is also referred to as a second phase shifter and a second modulation arm. The phase shifter 20-2 is connected between the second output terminal o2 of the beam splitter 31 and the second input terminal i2 of the beam splitter 32. Beam splitter 31 transmits the first part of the carrier optical signal O41 to phase shifter 20-1, and transmits the second part of the carrier optical signal O42 to phase shifter 20-2; phase shifter 20-1 is used to shift the phase of the first part of the carrier optical signal O41 according to electrical signal S1, and output the first part of the modulated optical signal O41'; phase shifter 20-2 is used to shift the phase of the second part of the carrier optical signal O42 according to electrical signal S1, and output the second part of the modulated optical signal O42'; beam splitter 32 is used to interfere the first part of the modulated optical signal O41' and the second part of the modulated optical signal O42', and output the modulated optical signal O4' through the output terminal o3 of beam splitter 32.

[0126] in, Figure 12 The modulator shown is specifically an MZ modulator, and in some embodiments, refer to Figure 13 As shown, the modulator can also be a micro-ring modulator. Figure 13 The micro-ring modulator 40 shown includes: an input / output waveguide 41, a ring waveguide 42, and at least one phase shifter 20 disposed on the ring waveguide 42; the input / output waveguide 41 is coupled to the ring waveguide 42; the phase shifter 20 is... Figure 2 or Figure 6 The phase shifter shown.

[0127] exist Figure 13 In the micro-ring modulator 40 shown, the input / output waveguide 41 is used to receive the carrier optical signal O5 through its first end, and couple the first portion of the carrier optical signal O51 into the ring waveguide 42. At least one phase shifter 20 is used to adjust the phase change (also called circumferential phase shift) of the first portion of the optical signal O51 transmitted within the ring waveguide 42 to generate the modulated optical signal O51'. The input / output waveguide 21 is also used to interfere the modulated optical signal O51' with the second portion of the carrier optical signal O52, and output the modulated optical signal O5' from the second end of the input / output waveguide 41.

[0128] In other embodiments, reference is made to Figure 13As shown, the modulator 40 also includes an input / output waveguide 43; the input / output waveguide 41 is coupled to a ring waveguide 42; and the input / output waveguide 43 is coupled to the ring waveguide 42. The input / output waveguide 41 is used to output the modulated optical signal O5' from its second end; the input / output waveguide 45 is used to receive a portion of the modulated optical signal O511 from the modulated optical signal O51' generated in the ring waveguide 42, and output the portion of the modulated optical signal O511 through the third end of the input / output waveguide 43. The first end of the input / output waveguide 41 and the third end of the input / output waveguide 43 are located on the same side of the ring waveguide 42.

[0129] Reference Figure 14 As shown, embodiments of this application also provide an optical device 50, which may specifically be an optical transmitting device. The optical device 50 includes a light source 51 and, as shown in the figure, an optical device 50. Figure 12 The light source 51 is used to output a carrier optical signal O4 to the optical device 30 shown.

[0130] Reference Figure 15 As shown, compared to Figure 14 The optical device 50 shown is... Figure 15 The optical device 50 shown includes a light source 51 and, as shown in the figure, ... Figure 13 The modulator 40 shown has a light source 51 for outputting a carrier optical signal O5 to the modulator 40.

[0131] Reference Figure 16 As shown, embodiments of this application also provide an optical device 60, which includes a detection device 61 and, as shown in the figure, an optical device 60. Figure 9 The optical device 30 shown has a third output terminal of the beam splitter 32 connected to the detection device 61. The optical device 30 is used to transmit the transmitted optical signal O2 received at the third input terminal of the beam splitter 31 to the detection device 61, or to transmit the transmitted optical signal O3 received at the fourth input terminal of the beam splitter 31 to the detection device 61. The detection device 61 is used to detect the parameters of the received optical signal.

[0132] In other embodiments, Figure 9 The cascaded optical devices 30 shown can realize an m*n optical switch. The target output terminal of the m*n optical switch is connected to the detection device 61. After any input terminal of the m*n optical switch is connected to the target output terminal, the detection device 61 can detect the parameters of the optical signal input to any input terminal of the m*n optical switch.

[0133] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and modifications.

Claims

1. A phase shifter, characterized in that, include: The lower cladding layer, waveguide layer, and upper cladding layer are arranged sequentially along the stacking direction; The phase shifter further includes a phase change material layer disposed between the waveguide layer and the upper cladding layer; When the phase of the first optical signal and the phase of the second optical signal input to the phase shifter are equal, and the crystallinity of the phase change material layer is a set value, the phase difference between the first optical signal and the second optical signal output by the phase shifter is less than or equal to 1 degree / micrometer. Wherein, the polarization direction of the first optical signal is the first polarization direction, the polarization direction of the second optical signal is the second polarization direction, and the first polarization direction is different from the second polarization direction.

2. The phase shifter according to claim 1, characterized in that, The phase change material layer includes a first layer structure; the first layer structure is located on the side of the waveguide layer away from the lower cladding layer.

3. The phase shifter according to claim 2, characterized in that, The dimension of the first layer structure along the first direction is greater than 0 and less than or equal to the dimension of the waveguide layer along the first direction; the first direction is perpendicular to the optical transmission direction and perpendicular to the stacking direction of the phase shifter; The dimensions of the first layer along the stacking direction are greater than 1 nanometer.

4. The phase shifter according to claim 3, characterized in that, The dimension of the first layer structure along the first direction is greater than 0 and smaller than the dimension of the waveguide layer along the first direction. The center of the first layer structure along the first direction and the center of the waveguide layer along the first direction are located at the same position in the first direction.

5. The phase shifter according to any one of claims 2-4, characterized in that, The waveguide layer is planar on the side closest to the first layer structure, and the first layer structure is planar on the side closest to the waveguide layer. Alternatively, the waveguide layer may include at least one first recess on the side near the first layer structure, and the first layer structure may include at least one first protrusion on the side near the waveguide layer, with the at least one first recess and the at least one first protrusion being provided in a one-to-one correspondence. Alternatively, the waveguide layer may include at least one second protrusion on the side near the first layer structure, and the first layer structure may include at least one second recess on the side near the waveguide layer, with the at least one second recess corresponding to the at least one second protrusion.

6. The phase shifter according to any one of claims 1-5, characterized in that, The phase change material layer includes a second layer structure and a third layer structure; the second layer structure is disposed on the first side of the waveguide layer along a first direction, and the third layer structure is disposed on the second side of the waveguide layer along the first direction; the first direction is perpendicular to the optical transmission direction and perpendicular to the stacking direction of the phase shifter.

7. The phase shifter according to claim 6, characterized in that, The dimension of the second layer structure along the stacking direction is greater than 0 and less than or equal to the sum of the dimension of the waveguide layer along the stacking direction and a first threshold; wherein, if the phase change material layer does not include the first layer structure, the first threshold is 0; if the phase change material layer includes the first layer structure, the first threshold is the dimension of the first layer structure along the stacking direction. The second layer structure has a dimension greater than 1 nanometer along the first direction; The third layer structure has the same dimensions as the second layer along the stacking direction, and the third layer structure has the same dimensions as the second layer along the first direction.

8. The phase shifter according to claim 7, characterized in that, The dimension of the second layer structure along the stacking direction is smaller than the sum of the dimension of the waveguide layer along the stacking direction and the first threshold. The side of the second layer structure near the lower cladding layer is separated from the side of the waveguide layer near the lower cladding layer by a first target distance. The side of the third layer structure near the lower cladding layer is separated from the side of the waveguide layer near the lower cladding layer by the first target distance. The first target distance is greater than or equal to 0.

9. The phase shifter according to any one of claims 1-8, characterized in that, The phase shifter also includes an electrode layer disposed on the side of the upper cladding away from the waveguide layer; The electrode layer is used to adjust the crystallinity of the phase change material layer.

10. The phase shifter according to claim 9, characterized in that, The phase change material layer includes a plurality of substructures arranged sequentially along the light transmission direction, and the electrode layer includes a plurality of sub-electrodes arranged sequentially along the light transmission direction. One of the sub-electrodes is used to adjust the crystallinity of one of the substructures.

11. The phase shifter according to any one of claims 1-10, characterized in that, The dimension L of the phase change material layer along the light transmission direction satisfies the following relationship: Where λ is the wavelength of the first optical signal or the second optical signal, and Δn eff The effective refractive index difference of the cross-section of the phase shifter when the phase change material layer switches between two different crystallinities. The phase change of the phase change material layer is the amount of phase change of the first optical signal or the second optical signal output by the phase shifter when the two different crystallinities are switched.

12. The phase shifter according to any one of claims 1-11, characterized in that, The phase change material layer comprises one or more of the following: antimony selenide, antimony trisulfide, antimony telluride germanium, and antimony germanium selenide telluride.

13. The phase shifter according to any one of claims 1-12, characterized in that, The phase shifter further includes a protective layer disposed between the phase change material layer and the upper cladding layer, the protective layer being used to restrict the flow of the phase change material layer.

14. An optical device, characterized in that, include: A first beam splitter, a second beam splitter, and at least one phase shifter, wherein the at least one phase shifter is connected between the first beam splitter and the second beam splitter; The phase shifter is the phase shifter according to any one of claims 1-13.

15. The optical device according to claim 14, characterized in that, The at least one phase shifter includes a first phase shifter; The first beam splitter is used to receive a first transmitted optical signal, transmit a first portion of the first transmitted optical signal to the first phase shifter, and transmit a second portion of the first transmitted optical signal to the second beam splitter. The first phase shifter is used to shift the phase of the first portion of the optical signal; The second optical splitter is used to output the first transmitted optical signal when the phase difference between the first part of the optical signal and the second part of the optical signal is 0, and not to output the first transmitted optical signal when the phase difference between the first part of the optical signal and the second part of the optical signal is π.

16. The optical device according to claim 14, characterized in that, The at least one phase shifter includes a first phase shifter; The first optical splitter is used to receive a second transmitted optical signal through the third input terminal of the first optical splitter, transmit a first part of the optical signal in the second transmitted optical signal to the first phase shifter, and transmit a second part of the optical signal in the second transmitted optical signal to the second optical splitter. The first phase shifter is used to shift the phase of the first portion of the optical signal; The second beam splitter is used to output the second transmitted optical signal through the fourth output terminal of the second beam splitter when the phase difference between the first part of the optical signal and the second part of the optical signal is 0, and to output the second transmitted optical signal through the third output terminal of the second beam splitter when the phase difference between the first part of the optical signal and the second part of the optical signal is π. The third input terminal of the first beam splitter and the fourth output terminal of the second beam splitter are centrally symmetrical.

17. The optical device according to claim 14, characterized in that, The at least one phase shifter includes a first phase shifter; The first optical splitter is used to receive a carrier optical signal, transmit a first portion of the carrier optical signal to the first phase shifter, and transmit a second portion of the carrier optical signal to the second optical splitter. The first phase shifter is used to shift the phase of the first portion of the carrier optical signal according to the electrical signal and output the first portion of the modulated optical signal; The second beam splitter is used to interfere with the first portion of the modulated optical signal and the second portion of the optical signal to output a modulated optical signal.

18. A modulator, characterized in that, include: A first input / output waveguide, a ring waveguide, and at least one phase shifter disposed on the ring waveguide; The first input / output waveguide is coupled to the ring waveguide; the phase shifter is the phase shifter according to any one of claims 1-13.

19. The modulator according to claim 18, characterized in that, The modulator further includes a second input / output waveguide; the second input / output waveguide is coupled to the ring waveguide.

20. An optical device, characterized in that, Includes a light source and the optical device as described in claim 17. The light source is used to output a carrier light signal to the optical device.

21. An optical device, characterized in that, Includes a light source and a modulator as described in claim 18 or 19. The light source is used to output a carrier light signal to the modulator.

22. An optical device, characterized in that, Includes a detection device and an optical device as described in claim 16, wherein the third output terminal of the second beam splitter in the optical device is connected to the detection device; The optical device is used to transmit the optical signal received at the third input terminal of the first beam splitter to the detection device, or to transmit the optical signal received at the fourth input terminal of the first beam splitter to the detection device. The detection device is used to detect the parameters of the received optical signal.

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