Spatial light modulators and wavelength selective switches

Abstract

This application provides a spatial light modulator and a wavelength-selective shape. The spatial light modulator includes a backplane with a built-in driving circuit, a phase adjustment unit, electrodes, and an electrical connection. The phase adjustment unit includes a lower cavity mirror, a cavity layer, and an upper cavity mirror, with the lower cavity mirror located between the cavity layer and the backplane. The electrodes include a first electrode and a second electrode, located in the phase adjustment unit on the side of the lower cavity mirror facing away from the backplane. The electrical connection electrically connects the electrodes and the driving circuit to form a driving electric field between the first and second electrodes, thereby adjusting the refractive index of the phase adjustment unit. This application can achieve low insertion loss, high-efficiency light conversion while increasing the duty cycle.

Description

Technical Field

[0001] This application relates to the field of optical communication, and in particular to a spatial light modulator and a wavelength selective switch. Background Technology

[0002] Optical networks are continuously evolving towards higher capacity, lower latency, and greater intelligence. Optical switching technologies such as ROADM (Reconfigurable Optical Add-Drop Multiplexer) and OXC (Optical Cross-Connect) not only support current commercial optical networks but are also key technologies for realizing next-generation optical networks. As a core device of OXC, the WSS (Wavelength Selective Switch) has an urgent need and practical value in port / channel expansion.

[0003] With the expansion of ports / channels, the trend in the industry is to achieve low insertion loss and high efficiency optical conversion while increasing the duty cycle, giving spatial light modulators and wavelength selective switches the advantages of small size and high performance. Summary of the Invention

[0004] This application provides a spatial light modulator and a wavelength selection switch that can achieve low insertion loss, high efficiency optical conversion, and increase duty cycle.

[0005] To achieve the above objectives, the embodiments of this application adopt the following technical solutions:

[0006] In a first aspect, embodiments of this application provide a spatial light modulator, including a backplate, a phase adjustment unit, electrodes, and an electrical connection portion. A driving circuit is disposed within the backplate. The phase adjustment unit includes a lower cavity mirror, a cavity layer, and an upper cavity mirror sequentially stacked on the backplate, with the lower cavity mirror located between the cavity layer and the backplate. The electrodes include a first electrode and a second electrode that are insulated from each other, located inside or on the surface of the phase adjustment unit, and on the side of the lower cavity mirror facing away from the backplate. Specifically, the electrodes are integrally formed with the phase adjustment unit, and the electrodes are fabricated inside or on the surface of the phase adjustment unit during fabrication. Alternatively, the electrodes can be disposed on the surface of a pre-fabricated phase adjustment unit. The electrical connection portion electrically connects the electrodes and the driving circuit to form a driving electric field between the first electrode and the second electrode, adjusting the refractive index of the phase adjustment unit, thereby modulating the phase of the optical signal. This application integrates the electrodes with the phase adjustment unit by forming the electrodes on the side of the lower cavity mirror away from the back plate. This means that the electrodes do not occupy the space of the back plate around the phase adjustment unit, which is beneficial to improving the duty cycle of the spatial light modulator and saving the space of the back plate.

[0007] Traditional spatial light modulator designs typically separate the electrodes from the phase correction unit on a backplane. The electrodes are positioned around the phase correction unit, occupying the area around the phase correction unit on the backplane. This not only results in a larger backplane area for the spatial light modulator but also means that the driving electric field generated by the electrodes can only act locally on the phase correction unit, with part of the electric field existing in the surrounding space and unable to act on the phase correction unit. Consequently, the voltage applied to the electrodes needs to be greater than the driving voltage required by the phase correction unit, which is detrimental to energy saving and results in low driving efficiency.

[0008] This application directly fabricates the electrodes on the phase adjustment unit. Only the driving voltage required by the phase adjustment unit needs to be applied to the electrodes, without the need for a large driving voltage. This results in advantages such as low insertion loss, low power consumption, and high-efficiency conversion.

[0009] In one possible implementation, the driving circuit, the phase adjustment unit, the electrode, and the connection portion together constitute a pixel unit. The spatial light modulator includes multiple pixel units, which are arranged in an array. The phase adjustment units of adjacent pixel units are seamlessly connected. In this embodiment, the multiple pixel units are arranged closely one after another on the backplane. The architecture of seamless connection between the phase adjustment units of adjacent pixel units makes it easy to miniaturize the spatial light modulator. Moreover, the architecture of seamless connection between adjacent phase adjustment units is also beneficial to manufacturing. During the manufacturing process, the phase adjustment units of the arrayed pixel units are manufactured simultaneously, and after manufacturing, it is not necessary to dig trenches between adjacent phase adjustment units, resulting in low manufacturing cost and high yield.

[0010] The phase adjustment unit in the spatial light modulator provided in this application has a solid-state layered structure architecture. In one embodiment, the phase adjustment unit is similar to an asymmetric FP (Fabry-Perot) microcavity structure. The lower cavity mirror, cavity layer, and upper cavity mirror of the phase adjustment unit are also architectures with multi-layered (or film) structures. The lower cavity mirror is a reflective layer composed of multi-layered (or film) structures or a metal reflective layer with a reflectivity close to or equal to 1. Corresponding layer structures between different pixels can be connected to the same layer. That is, during the fabrication of the lower cavity mirror on the backplane, a large-area reflective layer can be directly fabricated, which can cover multiple arrayed pixel units. The area corresponding to each pixel unit is the lower cavity mirror of that pixel unit. The cavity layer and upper cavity mirror are made of materials with electro-optic effects, such as BTO (BaTiO3, Barium titanate) and Si (silicon, such as Si nanomaterials). The response rates of such materials are on the order of GHz. To form the asymmetric architecture of the phase modulation unit in the FP microcavity structure, it can be formed by fabricating structures such as Si nanowires and nanopillars on the surface of the upper cavity mirror. Therefore, the phase modulation unit provided in this application can achieve phase modulation with near-zero wavefront amplitude variation in the optical signal. The spatial light modulation unit provided in this application can perform pure phase modulation on the optical signal without changing the light intensity.

[0011] The phase adjustment unit can be divided into a main region and an edge region. The edge region is located outside the main region and surrounds it. The main region is equivalent to the functional area of ​​the phase adjustment unit. Electrodes are set within the main region, while electrical connections can be located in the edge region. The phase adjustment unit provided in this application is an integrated structure. The division of the main region and the edge region does not mean that the phase adjustment unit can be divided into two parts. This embodiment emphasizes that the main region is the area where the electrodes are set. This can be understood as the electrode placement not covering all areas of the phase adjustment unit, but reserving the edge region. That is, no electrodes are set in the edge region, but electrical connections can be set in the edge region. When a voltage is applied to the electrodes, the resulting driving electric field is also located within the main region. This only changes the refractive index of the main region, and the main region performs phase adjustment on the optical signal. The edge region, since it does not have a driving electric field, will not affect the optical signal. In this way, the main regions of adjacent pixel units are separated by the edge regions, so that the phase adjustment of the optical signal between adjacent pixel units will not cause crosstalk.

[0012] In other embodiments, the electrodes may not only be arranged in the main body area, but may also extend to the edge area. However, through the configuration of the electrical connection, the driving electric field is generated only in the main body area when the electrodes are energized, which can also ensure the isolation of the driving electric field between adjacent pixel units, so that the phase adjustment of the optical signal between adjacent pixel units will not cause crosstalk.

[0013] The electrodes are made of a light-transmitting material, so that their placement within the main body region does not affect the light transmittance of the main body region. The electrodes can be in the form of nanowires; in one specific embodiment, the electrode material can be Si-doped. This application integrates the first and second electrodes with the phase adjustment unit, which can be understood as the first and second electrodes being formed on a certain layer of the cavity layer and upper cavity mirror structure of the phase adjustment unit. The first and second electrodes can be obtained by Si-doping and etching processes during the fabrication of the cavity layer and upper cavity mirror structure to obtain Si nanowires (as the first and second electrodes). One of the first and second electrodes is electrically connected to the reference voltage of the driving circuit, and the other is grounded, thus forming a driving electric field when a voltage is applied.

[0014] The electrical connection can be made of an opaque material, such as metal. Since the electrical connection is located in the edge area, its opaque material will not affect the light transmittance of the phase adjustment unit. The electrical connection can include a first electrical connection and a second electrical connection. The first electrical connection is electrically connected between the first electrode and the drive circuit, and the second electrical connection is electrically connected between the second electrode and the drive circuit. Specifically, the connection includes a pad and a conductive part electrically connected between the pad and the drive circuit. The pad can be located in the same layer as the electrode, and the conductive part can be in the form of a via lead. Specifically, during manufacturing, a via can be formed between the layer containing the pad and the backplate. A metal wire or a metal conductive pillar can be placed inside the via, or a metal layer can be formed on the inner wall of the via through electroplating to form the conductive part.

[0015] In one possible implementation, the electrodes are arranged on the first surface, meaning the first and second electrodes are coplanar, and during fabrication, the first and second electrodes are fabricated on the same layer structure. The phase adjustment unit includes multiple layer structures stacked sequentially, and the first surface is the surface of one of these layer structures. The first surface can be the surface of the upper laparoscope facing away from the cavity layer. Specifically, the lower laparoscope, cavity layer, and upper laparoscope can all be a structure of one or more layer structures stacked sequentially. As long as the first surface is not located in the lower laparoscope, it can be located in a layer structure of the cavity layer, a layer structure of the upper laparoscope, a layer structure between the cavity layer and the upper laparoscope, or a layer structure on the side of the upper laparoscope facing away from the cavity layer.

[0016] In one possible implementation, the electrodes are arranged in an interdigitated electrode architecture, specifically: the first electrode includes a first main line and at least two first branches extending from one side of the first main line, the second electrode includes a second main line and at least two second branches extending from one side of the second main line, the first main line and the second main line are arranged opposite to each other, and the first branches and the second branches constitute an interdigitated architecture.

[0017] In one possible implementation, the first branch and the second branch are in a straight line. Specifically, the first branch and the second branch can be arranged in parallel and both are perpendicular to the first main line or the second main line. The first branch and the second branch can also form an angle with the first main line and the second main line. When the angle is 90 degrees, it is the aforementioned perpendicular state. The angle can also be less than 90 degrees, such as 60 degrees, 75 degrees, etc. This application does not limit it.

[0018] In one possible implementation, the first branch and the second branch are curved, and their shapes can be S-shaped, C-shaped, arc-shaped, or other irregular curved shapes.

[0019] In one possible implementation, the electrical connection includes a first connection and a second connection that are insulated from each other. The first connection is connected to the first main line, and the second connection is connected to the second main line. The first and second connections are distributed on opposite sides of the electrode. Specifically, the first and second connections are located in the edge region of the phase adjustment unit. The first and second connections can be made of opaque materials, such as metal. Opaque materials have the advantage of low cost. By placing the electrical connections in the edge region, which serves as an isolation area between the main regions of adjacent phase adjustment units, and where the electrodes do not form a driving electric field, the edge region does not need to be transparent. Therefore, opaque electrical connections can be placed in the edge region. This ensures and improves the transmittance of the main region of the phase adjustment unit while achieving low cost for the spatial light modulator.

[0020] In one possible implementation, the first electrode and the second electrode extend side-by-side synchronously from a first position on the first surface to a second position on the first surface, with insulation between them. Specifically, the paths extending from the first electrode and the second electrode are zigzag, serpentine, or spiral. The paths extending from the first electrode and the second electrode include multiple consecutive straight segments or continuous curves. In this architecture, both the first and second connecting portions of the electrical connection can be located at the first position, which is located at the outer edge of the electrode. The first position is located in the edge region of the phase adjustment unit. In other implementations, the electrical connection can also be located at the second position; or the first and second electrical connections can be arranged at the first and second positions respectively. If the second position is located in the main body region of the phase adjustment unit, the electrical connection at the second position can be made of a light-transmitting material to avoid affecting light transmittance.

[0021] In one possible implementation, the lower laminar flow mirror, the cavity layer, and the upper laminar flow mirror are stacked sequentially along a first direction, which can be understood as a direction perpendicular to the backplate. The first electrode and the second electrode are alternately stacked along the first direction. That is, in this implementation, the first electrode and the second electrode are not located in the same layer (referring to the same layer of the phase adjustment unit), but are formed in different layers of the phase adjustment unit. This can be understood as follows: each first electrode and each second electrode is a film structure, distributed planarly within a certain layer of the cavity layer or a certain layer of the upper laminar flow mirror. Different electrodes are located in different layers, and adjacent electrodes are isolated by an insulating layer, which is a layer of the phase adjustment unit and can be an electro-optic dielectric. The first electrode and the second electrode are alternately stacked, meaning that a second electrode is disposed in a layer structure adjacent to one of the first electrodes, and a first electrode is disposed in a layer structure adjacent to one of the second electrodes. One first electrode can be sandwiched between two adjacent second electrodes.

[0022] In one possible implementation, the electrode is located within the cavity layer. The advantage of fabricating the electrode within the cavity layer is that the fabrication process is relatively simple. Because the cavity layer is made of a single material, there is no need to consider whether it generates transmittance or reflectance. For the cavity layer, transmittance is controlled by the material itself, not by its specific structure. Although the electrode alters the structure of the cavity layer, its impact on transmittance is minimal because transmittance is controlled by the material.

[0023] In one possible implementation, the electrodes are located inside the upper laparoscope, and the principle of fabricating the electrodes in the upper laparoscope is the same as the principle of fabricating the electrodes in the cavity layer. The upper laparoscope mainly forms an asymmetric structure, and the asymmetric structure is mainly formed at the top of the upper laparoscope, that is, the surface of the upper laparoscope away from the cavity layer.

[0024] In one embodiment, some electrodes are located in the cavity layer, and some electrodes are located in the upper endoscope.

[0025] For embodiments where the electrodes have a multi-layer structure, the specific architecture of the electrical connection portion can be as follows: the electrical connection portion includes a first connection portion and a second connection portion that are insulated from each other, the first electrode and the second electrode partially overlap, the portion of the first electrode that does not overlap with the second electrode is connected to the first connection portion, and the portion of the second electrode that does not overlap with the first electrode is connected to the second connection portion.

[0026] In one possible implementation, for a multi-layered electrode architecture, the number of first electrodes is two or more, and the number of second electrodes is two or more. Since the first and second electrodes generate an electric field when energized, setting the number of electrodes to two or more allows for the generation of the required electric field using a smaller voltage. The number of first or second electrodes can be controlled to 2-3 layers, because if the number of layers is too large, such as exceeding 3 layers, it becomes difficult to implement from a manufacturing perspective. Therefore, the maximum number of electrode layers is 6, with 3 layers for the first electrodes and 6 layers for the second electrodes.

[0027] The fabrication process for each electrode layer may include the following steps:

[0028] The sputtering process is used to fabricate an electrode layer on the surface of a certain layer of the phase adjustment unit by sputtering. The electrode layer can be made of doped silicon.

[0029] The photolithography process involves coating a photoresist layer onto an electrode layer and then using the photolithography process to form a preset pattern from the photoresist layer.

[0030] An etching process is used to form the preset pattern on the electrode layer;

[0031] Planarization is a process used to flatten patterned electrodes. This can be achieved through polishing, such as chemical mechanical polishing.

[0032] The number of layers of the first electrode and the second electrode is not necessarily the same. For example, in one possible implementation, the electrode includes one layer of the first electrode and two layers of the second electrode, or two layers of the second electrode and three layers of the first electrode.

[0033] In embodiments where the electrodes are located on the same surface, i.e., where the electrodes are formed on the first surface, the number of the first electrode and the second electrode can also be the same; for example, the number of the first electrode can be one, and the number of the second electrode can also be one. The number of the first electrode and the second electrode can also be two or more, and the number of corresponding electrical connections can increase accordingly. The number of the first electrode and the second electrode can also be different; for example, one first electrode paired with two second electrodes can form an electrode structure.

[0034] In one possible implementation, the phase adjustment unit has a protruding structure on the surface opposite to the backplate. This protruding structure is formed on the top layer of the upper cavity mirror (i.e., the layer opposite to the cavity layer of the upper cavity mirror). Alternatively, the protruding structure can be understood as being located on the side of the upper cavity mirror opposite to the cavity layer, meaning it is independent of the upper cavity mirror. The protruding structure enables the phase adjustment unit to form an asymmetric architecture, which is used to suppress modulation of the optical signal intensity, making the spatial light modulator provided in this application tend towards pure phase modulation.

[0035] In one possible implementation, the electrode is disposed on the surface of the upper cavity mirror away from the cavity layer, and the surface of the electrode is provided with a plurality of micropillar structures. The micropillar structures are used to suppress intensity modulation of the optical signal, so that the spatial light modulator provided in this application tends to pure phase modulation.

[0036] In one possible implementation, the electrodes are disposed on the surface of the upper laminar mirror away from the cavity layer, and an electro-optic medium is provided between the first electrode and the second electrode; alternatively, an electro-optic medium is provided both between the first electrode and the second electrode and around the electrodes. This embodiment places the electrodes on the surface of the upper laminar mirror away from the cavity layer. Through the structure of electrodes combined with an electro-optic medium, the aforementioned protruding structure can be formed on the surface of the upper laminar mirror while simultaneously creating the electrodes, i.e., constituting an asymmetric structure. This allows the phase adjustment unit to only adjust the phase of the optical signal without affecting its intensity.

[0037] Secondly, this application provides a wavelength selective switch, including an optical fiber array, a main lens, and a spatial light modulator as described in any possible embodiment of the first aspect. The light beam detected by the optical fiber array is transformed into collimated light after passing through the main lens. The collimated light enters the spatial light modulator, and the spatial light collimator is used to reflect and deflect the collimated light to form reflected light. The reflected light is focused onto the optical fiber array by the main lens. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of an optical switching node networking system;

[0039] Figure 2 This is a schematic diagram of a wavelength selective switch provided in an embodiment of this application;

[0040] Figure 3 This is a cross-sectional view of the backplate of a spatial light modulator provided in one embodiment of this application;

[0041] Figure 4 This is a plan view of the backplate of a spatial light modulator provided in one embodiment of this application;

[0042] Figure 5 This is a cross-sectional view of a spatial light modulator provided in one embodiment of this application;

[0043] Figure 6 This is a plan view of a spatial light modulator provided in one embodiment of this application;

[0044] Figure 7 This is a schematic diagram of a spatial light modulator provided in one embodiment of the present application, which includes three phase adjustment units;

[0045] Figure 8This is a schematic diagram of a spatial light modulator provided in one embodiment of the present application, which includes three phase adjustment units and schematically illustrates that the phase adjustment units include a multi-layer structure;

[0046] Figure 9 This is a schematic diagram of a spatial light modulator provided in one embodiment of this application;

[0047] Figure 10 This is a schematic diagram of a spatial light modulator provided in one embodiment of this application;

[0048] Figure 11 This is a schematic diagram of a spatial light modulator provided in one embodiment of this application;

[0049] Figure 12 This is a schematic diagram of a spatial light modulator provided in one embodiment of this application;

[0050] Figure 13 This is a schematic diagram of the electrode distribution of a spatial light modulator provided in one embodiment of this application;

[0051] Figure 14 This is a schematic diagram of the electrode distribution of a spatial light modulator provided in one embodiment of this application;

[0052] Figure 15 This is a schematic diagram of the electrode distribution of a spatial light modulator provided in one embodiment of this application;

[0053] Figure 16 This is a schematic diagram of a spatial light modulator provided in one embodiment of this application;

[0054] Figure 17 This is a schematic diagram of a spatial light modulator provided in one embodiment of this application;

[0055] Figure 18 This is a schematic diagram of the electrode portion in a spatial light modulator provided in one embodiment of this application, wherein the electrodes are provided with micropillar structures;

[0056] Figure 19 This is a schematic diagram of a spatial light modulator provided in one embodiment of this application;

[0057] Figure 20 This is a schematic diagram of the multilayer electrode architecture of a spatial light modulator provided in one embodiment of this application;

[0058] Figure 21 This is a schematic diagram of a spatial light modulator provided in one embodiment of this application;

[0059] Figure 22 This is a schematic diagram of a spatial light modulator provided in one embodiment of this application;

[0060] Figure 23 This is a schematic diagram of a spatial light modulator provided in one embodiment of this application;

[0061] Figure 24 This is a schematic diagram of the electric field distribution of the interdigitated electrode architecture of a spatial light modulator provided in one embodiment of this application;

[0062] Figure 25 This is a schematic diagram of the electric field distribution of the electrodes in a multilayer structure of a spatial light modulator provided in one embodiment of this application. Detailed Implementation

[0063] The embodiments of this application are described below with reference to the accompanying drawings.

[0064] The wavelength selective switch (WSS) provided in this application embodiment is used in an optical switching node networking system. Please refer to... Figure 1 The optical switching node networking system 1000 includes a wavelength selection switch group 1 connected between local A and the pass-through optical path B. Wavelength selection switch group 1 includes multiple wavelength selection switches 1' connected in parallel between local A and the pass-through optical path B. Wavelength selection switches 1' are used to download optical signals of a specific wavelength from the pass-through optical path B to local A, or to upload optical signals of a specific wavelength from local A to the pass-through optical path B. Local A can be understood as a local equipment room, containing equipment such as circuit boards and switches. The pass-through optical path B can be understood as an optical path formed by the interconnection of multiple WSS100s. Each WSS100 is connected to other nodes via optical fiber 2.

[0065] This application provides a wavelength selection switch that can be applied to ROADM (Reconfigurable Optical Add-Drop Multiplexer). Please refer to... Figure 2 The wavelength selection switch 100 includes an optical fiber array 20, a main lens 30, and a spatial light modulator (SLM) 10. The optical fiber array 20 includes input and output ports, such as... Figure 2 As shown, this schematically illustrates one output port I and four input ports O1, O2, O3, and O4. The positions of the output port I and each input port O1, O2, O3, and O4 can be designed according to specific application scenarios and are not limited to the following: Figure 2 The diagram shows a structure with output port I located in the middle and two input ports on each side of output port I. The optical signal emitted from output port I is the incident light (i.e., Figure 2The solid line between the fiber array 20 and the main lens 30, with the arrow pointing towards the main lens 30, represents the portion of the light rays. The main lens 30 is used to transform the incident light into collimated light (i.e., Figure 2 The solid line between the primary lens 30 and the spatial light modulator 10, with the arrow pointing towards the spatial light modulator 10, represents a portion of the light ray. The spatial light modulator 10 is a phase-type SLM used to change the phase of the optical signal. After the collimated light enters the spatial light modulator 10, the spatial light modulator 10 reflects and deflects the beam. The deflected and reflected light is the outgoing light (i.e.,...). Figure 2 The emitted light (the portion of the light rays between the main lens 30 and the spatial light modulator 10, with the arrow pointing towards the main lens 30) passes through the main lens 30 and is focused and coupled to the input port O4.

[0066] The spatial light modulator provided in this application can also be used in other application scenarios, such as: N×N WSS, ADWSS, LiDAR, laser display, etc.

[0067] The spatial light modulator provided in this application is a phase-type spatial light modulator, which adjusts the phase of the optical signal without changing the intensity of the optical signal. For example... Figures 3 to 6 As shown, Figure 3 and Figure 4 The cross-sectional and planar schematic diagrams of the backplate 110 are described respectively. Figure 5 and Figure 6 A cross-sectional view and a planar view of the spatial light modulator 10 are described respectively. The spatial light modulator 10 provided in this application includes a backplane 110 and a pixel array 120 formed on the backplane.

[0068] like Figure 3 and Figure 4 As shown, a plurality of driving circuits 111 arranged in an array are disposed within the backplate 110, for example, the driving circuits 111 are arranged in an M-row N-column configuration. The driving circuits 111 are circuit architectures fabricated within the backplate 110, which can be formed on one or more layers of the backplate 110, or they can be individual electronic components embedded within the backplate 110. The backplate 110 can be a ceramic substrate or a substrate of other materials. The backplate 110 includes a front side S1 and a back side S2 arranged opposite to each other. The front side S1 is used to form the pixel array 120, and can also be understood as the surface for fabricating the phase adjustment unit. The front side S1 is provided with an interface 112 for electrically connecting the driving circuits 111. Each driving circuit 111 corresponds to two interfaces 112. One interface 112 is electrically connected to the reference voltage of the driving circuit 111, and the other interface 112 is electrically connected to the ground of the driving circuit 111. This interface 112 can be a pad structure, and the surface of the pad can be coplanar with the front side S1, so that the front side S1 remains planar, making it easy to fabricate the pixel array 120.

[0069] Combination Figure 5 and Figure 6 The pixel array 120 includes a plurality of pixel units 121 arranged in an array (e.g., M rows and N columns). The pixel array 120 is fabricated on the front side S1 of the back plate 110. Each pixel unit 121 is interconnected as one unit, and adjacent pixel units 121 are seamlessly connected.

[0070] See Figure 7 and Figure 8 Each pixel unit 121 has the same architecture, including a driving circuit 111 (located within the backplate 110), a phase adjustment unit 20 (formed on the front side S1 of the backplate 110), an electrode 30 (formed in the phase adjustment unit 20), and an electrical connection portion 40 (formed in the phase adjustment unit 20). The phase adjustment unit 20 has a solid-state layer structure. Structurally, adjacent phase adjustment units 20 are interconnected as a single unit, with no gaps between them. Multiple arrayed phase adjustment units 20 are arranged closely side-by-side on the front side S1 of the backplate 110, facilitating the miniaturization of the spatial light modulator 10. In terms of manufacturing process, each phase adjustment unit 20 is formed through the same manufacturing steps, with each step simultaneously forming a certain layer of all phase adjustment units 20. Figure 8 The illustration schematically shows that each pixel unit 121 includes a multi-layer structure, and all pixel units 121 have the same number of layers. All layers are interconnected to form the same layer architecture. Notably, all electrodes 30 are located on the same layer. This architecture simplifies the fabrication process and reduces manufacturing costs. After fabricating the phase adjustment unit 20 on the backplane, this application eliminates the need to create channels between adjacent phase adjustment units 20, resulting in low manufacturing costs and high yield.

[0071] Since all pixel units 121 have the same architecture, the detailed architecture of one of the pixel units 121 will be described below.

[0072] See Figures 9 to 12The phase adjustment unit 20 includes a lower cavity mirror 21, a cavity layer 22, and an upper cavity mirror 23 sequentially stacked on the backplate 110. The lower cavity mirror 21 is located between the cavity layer 22 and the backplate 110. The phase adjustment unit 20 in the spatial light modulator provided in this application has a solid-state layered structure architecture. In one embodiment, the phase adjustment unit 20 is an asymmetric FP (Fabry-Perot) microcavity, in which the lower cavity mirror 21, cavity layer 22, and upper cavity mirror 23 are also architectures with multilayered structures (or film structures). The lower cavity mirror 21 is a reflective layer composed of multilayered structures (or film structures) or a metal reflective layer. The reflectivity of the lower cavity mirror 21 is close to or equal to 1. The corresponding layer structures between different pixel units 121 can be connected to form the same layer. In other words, during the fabrication of the lower cavity mirror 21 on the backplane 110, a large-area reflective layer can be directly fabricated. This large-area reflective layer can cover multiple arrayed pixel units 121, and a portion of the large-area reflective layer corresponding to each pixel unit 121 constitutes the lower cavity mirror 21 for that pixel unit. The cavity layer 22 and the upper cavity mirror 23 are made of materials with electro-optic effects, such as BTO (BaTiO3, Barium titanate) and Si (silicon, such as Si nanomaterials). The response rates of these materials are on the order of GHz. An asymmetric FP microcavity structure can be formed by fabricating Si nanowires, nanopillars, or other structures on the surface of the upper cavity mirror 23. By designing the structure of the asymmetric FP microcavity, phase modulation with near-zero wavefront amplitude variation of the optical signal can be achieved. The spatial light modulation unit provided in this application can perform pure phase modulation of the optical signal without changing the light intensity.

[0073] See Figure 5 and Figure 6 The phase adjustment unit 20 can be divided into a main region A and an edge region B. The edge region B is located outside the main region A and surrounds the main region A, such as... Figure 5 and Figure 6 As shown, the main area A is the part within the dashed box. Figure 6 As can be seen, the main area A is a square area, and the edge area B surrounds the main area A, forming a frame-shaped area outside the main area A.

[0074] The phase adjustment unit 20 provided in this application is an integral structure. The division of the main area A and the edge area B does not mean that the phase adjustment unit 20 can be divided into two parts. In one embodiment, it can be understood that the main area A is the area where the electrode 30 is set. The setting of the electrode 30 cannot cover all areas of the phase adjustment unit 20, but the edge area B should be reserved. That is, the edge area B is not set with the electrode 30, but the electrical connection part 40 can be set in the edge area B.

[0075] The main region A corresponds to the functional area of ​​the phase adjustment unit 20. The electrode 30 is disposed within the main region A, and the electrical connection portion 40 can be located in the edge region. When a voltage is applied to the electrode, the generated driving electric field is also located within the main region. This changes only the refractive index of the main region, allowing the main region to adjust the phase of the optical signal. The edge region, lacking a driving electric field, does not affect the optical signal. Thus, the main regions of adjacent pixel units are separated by the edge regions, preventing crosstalk between adjacent pixel units in adjusting the phase of the optical signal. In other embodiments, the electrode 30 can also be disposed in both the main region A and the edge region B, with the electrical connection portion 40 located in the edge region. The area between the electrical connection portions 40 is the main region A. When a voltage is applied, only a portion of the electrode 30 within the main region A generates a driving electric field. In summary, this application aims to ensure that the driving electric field is distributed within the main region A, while no driving electric field is distributed within the edge region B. This isolates the driving electric fields between adjacent pixel units, preventing crosstalk between adjacent pixel units to the optical signal.

[0076] In other embodiments, the electrode 30 may not only be arranged in the main body region A, but may also extend to the edge region B. However, by configuring the electrical connection part 40, the electrode 30 generates a driving electric field only in the main body region A when it is energized, which can also ensure the isolation of the driving electric field between adjacent pixel units, so that the phase adjustment of the light signal between adjacent pixel units will not cause crosstalk.

[0077] The electrode 30 includes a first electrode and a second electrode that are insulated from each other. The electrode 30 is located inside or on the surface of the phase adjustment unit 20, and is located on the side of the lower endoscope 21 opposite to the back plate 110. The electrode 30 can be formed in the phase adjustment unit 20. Specifically, the electrode 30 can be fabricated simultaneously during the fabrication of the phase adjustment unit 20. The electrode 30 can be formed in one or more layers of the phase adjustment unit 20, or on the surface of the phase adjustment unit 20, or it can be disposed on the fabricated phase adjustment unit 20. The electrical connection portion 40 includes a first electrical connection portion 41 and a second electrical connection portion 42. The electrical connection portion 40 electrically connects the electrode 30 and the driving circuit 111. The first electrical connection portion 41 is electrically connected between the first electrode and the driving circuit 111, and the second electrical connection portion 42 is electrically connected between the second electrode and the driving circuit 111, so as to form a driving electric field between the first electrode and the second electrode to adjust the refractive index of the phase adjustment unit 20.

[0078] For the configuration of electrode 30, it can be set to a single-layer architecture, such as... Figures 9 to 12 The illustrated embodiment.

[0079] For the single-layer structure of electrode 30, it can be understood that electrode 30 is arranged on the first surface S1, that is, coplanar. During the manufacturing process, the first electrode and the second electrode are fabricated on the same layer structure. The phase adjustment unit 20 includes multiple layer structures stacked sequentially, and the first surface S1 is the surface of one of the layer structures. Specifically, the lower laparoscope 21, the cavity layer 22, and the upper laparoscope 23 can all be a structure with one or more layers stacked sequentially, as long as the first surface S1 is not located in the lower laparoscope 21.

[0080] like Figure 9 As shown, the first surface S1 can be located in cavity layer 22. Figure 9 The first surface S1 shown is the surface of the bottom layer of the cavity layer 22, that is, the surface of the cavity layer 22 adjacent to the lower endoscope 21. Of course, the first surface S1 can also be the surface of other layers of the cavity layer 22. The electrode 30 is on the first surface S1. The electrode 30 can cover part of the first surface S1 or the entire first surface S1.

[0081] like Figure 10 The embodiment shown is similar to... Figure 9 The difference in the embodiment shown is that the first surface S1 is the surface of a certain intermediate layer of the cavity layer 22, and the electrode 30 is located in the intermediate layer of the cavity layer 22.

[0082] like Figure 11 The embodiment shown is similar to... Figure 9 The difference in the embodiment shown is that the first surface S1 is the bottom surface of the upper laminar mirror 23 (i.e. the surface of the upper laminar mirror 23 adjacent to the cavity layer 22), and the electrode 30 is located at the bottom layer of the upper laminar mirror 23.

[0083] like Figure 12 The embodiment shown is similar to... Figure 9 The difference in the embodiment shown is that: the first surface S1 is the surface on which the top layer of the upper laparoscope 23 is made, and the electrode 30 is located on the top layer of the upper laparoscope 23, that is, the electrode 30 is located in the layer structure of the upper laparoscope 23 on the side away from the cavity layer 22.

[0084] For a single-layer electrode 30, the specific structural form of the electrode 30 can be an interdigitated electrode architecture or a parallel line electrode architecture.

[0085] One possible implementation of electrode 30 as an interdigitated electrode structure is as follows: See Figure 13Electrode 30 is located in the main body region A, and electrical connection portion 40 is located in the edge region B. Electrode 30 includes a first electrode 31 and a second electrode 32, and electrical connection portion 40 includes a first electrical connection portion 41 and a second electrical connection portion 42. The pad portion of the first electrical connection portion 41 and the pad portion of the second electrical connection portion 42 are shown on the first surface S1. It can be understood that the first electrical connection portion 41 also includes a conductive portion. Figure 13 (Only the pad portion is shown, the conductive portion is not shown) It is connected between the pad and the driving circuit in a direction perpendicular to the first surface S1. Similarly, the second electrical connection portion 42 also includes a conductive portion that is electrically connected between the pad and the driving circuit in a direction perpendicular to the first surface S1. The first electrode 31 includes a first main line 311 and at least two first branches 312 extending from one side of the first main line 311. The second electrode 32 includes a second main line 321 and at least two second branches 322 extending from one side of the second main line 321. The first main line 311 and the second main line 321 are arranged opposite to each other. The first branch 312 and the second branch 322 form an interdigitated structure. The interdigitated structure can be understood as follows: the first branch 312 is inserted between two adjacent second branches 322, and the first branch 312 and the second branch 322 are arranged alternately. The arrangement pattern can be: one first branch 312, one second branch 322, one first branch 312, and so on. Figure 13 In the illustrated embodiment, there are five first branches 312 and five second branches. The first branches 312 and the second branches 322 are straight lines, with each first branch 312 parallel to and partially overlapping with the adjacent second branch 322. Specifically, the first branches 312 and the second branches 322 can be arranged in parallel and are both perpendicular to the first main line 311 or the second main line 321.

[0086] The first branch 312 and the second branch 322 can form an angle with the first main line 311 and the second main line 321. When the angle is 90 degrees, it is the aforementioned perpendicular state. The angle can also be less than 90 degrees, such as 60 degrees, 75 degrees, etc. This application does not limit it.

[0087] See Figure 14 , Figure 14 The implementation methods shown are the same as Figure 13 The difference in the implementation shown is that the first branch 312 and the second branch 322 are curved, and the shape of the first branch 312 and the second branch 322 can be S-shaped, C-shaped, arc-shaped, spiral-shaped or other irregular curved shapes.

[0088] In other embodiments, the first branch 312 and the second branch 322 can be a combination of multiple straight lines, such as an L-shape, or a combination of straight lines and curves, etc. This application does not limit the specific implementation.

[0089] See Figure 13 and Figure 14 The first connecting part 41 is connected to the first main line 311, and the second connecting part 42 is connected to the second main line 321. The first connecting part 41 and the second connecting part 42 are distributed on opposite sides of the electrode 30. Specifically, the first connecting part 41 and the second connecting part 42 are located in the edge region B of the phase adjustment unit 20. The first connecting part 41 and the second connecting part 42 can be made of opaque material, such as metal. Opaque material has the advantage of low cost. The electrical connecting part 40 is placed in the edge region B, which is the isolation area between the main regions A of adjacent phase adjustment units 20. When the electrode 30 is energized, no driving electric field is formed in the edge region B. Therefore, the edge region B does not need to be transparent. The opaque electrical connecting part 40 can be placed in the edge region B, avoiding the need to place the opaque electrical connecting part 40 in the main region A. This ensures the transmittance of the main region A of the phase adjustment unit 20, improves the transmittance, ensures the isolation between adjacent phase adjustment units, and achieves low cost of spatial light modulator.

[0090] One possible implementation of electrode 30 with a parallel line electrode structure is as follows: See Figure 15 The first electrode 31 and the second electrode 32 extend side by side from the first position L1 on the first surface S1 to the second position L2 on the first surface S1, with an insulating gap between the first electrode 31 and the second electrode 32. Figure 15 In the illustrated embodiment, both the first electrode 31 and the second electrode 32 are constructed along a single main line, without any other branches. To meet the requirements of the driving electric field, this application can also... Figure 15 Based on the illustrated embodiment, a branch design is added to the main line architecture of the first electrode 31 and the second electrode 32. Specifically, the paths extending from the first electrode 31 and the first electrode 32 are zigzag, serpentine, or spiral. The paths extending from the first electrode 31 and the second electrode 32 include multiple consecutive straight line segments or continuous curves. In this architecture, the first connection portion 41 and the second connection portion 42 of the electrical connection portion 40 can both be located at the first position L1, which is located at the outer edge of the electrode 30. The first position L1 is located within the edge region B of the phase adjustment unit 20.

[0091] In other embodiments, the electrical connection part 40 may be located at the second position L2. Since the second position L2 is within the main body area A, the electrical connection part 40 needs to be set to a light-transmitting state. Alternatively, although the electrical connection part 40 is made of an opaque material, its size may be appropriate and will not affect the light transmittance of the main body area A.

[0092] In other embodiments, the first electrical connection portion 41 and the second electrical connection portion 42 may be arranged at the first position L1 and the second position L2, respectively.

[0093] Figures 13 to 15 In the illustrated embodiment, the number of first electrode 31 and second electrode 32 is the same, one in each case. In other embodiments, for a coplanar single-layer electrode structure, the number of first electrode 31 and second electrode 32 can also be at least two, for example, two first electrodes paired with two second electrodes, and the number of corresponding electrical connection portions 40 can be increased accordingly. Alternatively, the number of first electrode 31 and second electrode 32 can also be different, for example, one first electrode 31 paired with two second electrodes 32 to form an electrode structure.

[0094] See Figure 16 In one possible implementation, the electrode 30 is disposed on the surface of the upper endoscope 23 opposite to the cavity layer 22. In this embodiment, the electrode 30 is an interdigitated electrode structure, with a specific structure similar to [other embodiments]. Figure 13 The example shown. Figure 16 In the illustrated embodiment, the first electrode 31 and the second electrode 32 protrude from the top surface of the upper endoscope 23, and the first electrical connection portion 41 and the second electrical connection portion 42 also protrude from the top surface of the upper endoscope 23. The area between the first electrode 31 and the second electrode 32 and the area surrounding the first electrode 31 and the second electrode 32 is filled with air.

[0095] See Figure 17 This implementation method is the same as Figure 16 The difference in the illustrated embodiment is that an electro-optic medium 50 is provided between the first electrode 31 and the second electrode 32. The material of the electro-optic medium 50 can be, for example, EO Polymer, LiNbO3, BTO, etc. The electro-optic medium 50 can also be provided around the first electrode 31 and the second electrode 32. In this embodiment, the first electrical connection portion 41 and the second electrical connection portion 42 are also surrounded by the electro-optic medium 50. It can be understood that the electrode 30 is embedded within the electro-optic medium 50, and the top surface of the electrode 30 and the top surface of the electro-optic medium 50 can be coplanar, or the top surface of the electrode 30 can protrude beyond the top surface of the electro-optic medium 50. The "top surface" refers to the surface of the electrode 30 and the electro-optic medium 50 that is away from the upper cavity mirror 23. In this embodiment, the electrode 30 is disposed on the surface of the upper cavity mirror 23 away from the cavity layer 22. Through the structure of the electrode 30 combined with the electro-optic medium 50, while the electrode 30 is formed on the surface of the upper cavity mirror 23, it can also have the function of "setting a protruding structure on the surface of the upper cavity mirror to achieve an asymmetric structure". That is, the electrode 30 and the electro-optic medium 50 constitute an asymmetric structure. Therefore, in this embodiment, the phase adjustment unit 20 can achieve phase adjustment only on the optical signal without affecting the intensity of the optical signal.

[0096] Figure 17The illustrated embodiment can be understood as follows: the upper cavity mirror 23 is a 100nm thick SiO2 layer. In this embodiment, the upper cavity mirror 23 can be considered as a layered structure made of a single SiO2 material. In other embodiments, the upper cavity mirror 23 can also be a multi-layered structure with different materials for adjacent layers, such as a SiO2 layer, a doped Si layer, another SiO2 layer, a doped Si layer, and so on. A 250nm thick doped Si layer is formed on the surface of the upper cavity mirror 23. The doped Si layer is used to fabricate the electrode 30. The doped Si layer is etched to obtain Si nanowires (i.e., the first and second branches in the electrode 30), with a width of 200nm and a length of 1.8µm. The center-to-center spacing between adjacent nanowires is 400nm. Then, EO-Polymer is filled into the center-to-center spacing between adjacent nanowires, completely filling the spaces between and around the Si nanowires. The EO-Polymer is also formed on the surface of the upper cavity mirror 23, with the Si nanowires and EO-Polymer forming the same layer. Adjacent nanowires are separated by compartments, with the EO-Polymers within these compartments exhibiting opposite polarization directions. Odd-numbered Si nanowires (1, 3, 5) (i.e., the first branches of the first electrode) are connected via horizontal lower Si strip structures (i.e., the first main line of the first electrode) (forming the first electrode) and contact the top electrode of the metal via (i.e., the pad of the first electrical connection). Even-numbered Si nanowires (2, 4, 6) (i.e., the second branches of the second electrode) are connected via horizontal upper Si strip structures (i.e., the second main line of the second electrode) (forming the second electrode) and contact the top electrode of another metal via (i.e., the pad of the second electrical connection). The horizontal Si strip structures (i.e., the first and second main lines) are 200 nm wide and 2 μm long. To avoid short circuits, the spacing between the odd-numbered (1,3,5) Si nanowires (i.e., the first branch) and the horizontal upper Si strip structure (i.e., the second main line) is 100 nm; the spacing between the even-numbered (2,4,6) Si nanowires (i.e., the second branch) and the horizontal lower Si strip structure (i.e., the first main line) is 100 nm.

[0097] See Figure 18 and Figure 19 When the electrode 30 is disposed on the surface of the upper cavity mirror 23 away from the cavity layer 22, the surface of the electrode 30 is provided with a plurality of micropillar structures 60. The micropillar structures 60 are used to suppress intensity modulation of the optical signal, so that the spatial light modulator provided in this application tends to pure phase modulation. Figure 18 A planar schematic diagram of a micropillar structure 60 for the first electrode 31 and the second electrode 32, wherein the first electrode 31 and the second electrode 32 are interdigitated electrode structures. Figure 19 In order to be in Figure 17 Based on the implementation method, a micro-pillar structure 60 was added to the architecture. Figure 19 In the illustrated embodiment, each micropillar structure 60 is block-shaped and distributed on the branches of each electrode. The micropillar structure 60 can also be other shapes, such as cylindrical or spherical. In one embodiment, the micropillar structures 60 can be uniformly distributed on the electrode 30. In other embodiments, the micropillar structures 60 can be distributed with different densities in different regions of the electrode 30; for example, the density of micropillar structures 60 near the center of the phase adjustment unit is lower than the density of micropillar structures 60 near the edge of the phase adjustment unit.

[0098] The first electrode 31 and the second electrode 32 of the single-layer structure electrode 30 can be nanowire structures, and the material can be doped Si.

[0099] In the foregoing embodiments, the phase adjustment unit may include a single-layer structure (e.g., an interdigitated electrode structure and a parallel-line electrode structure). This application does not limit the number of single-layer electrode layers; that is, a phase adjustment unit within a pixel unit may include only one single-layer electrode structure. This single-layer electrode structure can operate independently, generating a driving electric field to change the refractive efficiency or coupling efficiency of the phase correction unit, thereby adjusting the phase of the reflected light. A phase adjustment unit within a pixel unit may also include at least two single-layer electrode structures, each independent of the others. Multiple single-layer electrode structures can be electrically connected to the same driving circuit. The driving circuit can drive all single-layer electrode structures simultaneously, or selectively drive only some of the single-layer electrode structures as needed.

[0100] For the electric field distribution and refractive index variation of electrodes in a single-layer structure, please refer to [link to relevant documentation]. Figure 24 The diagram on the left shows one of the first and second electrodes connected to a reference voltage, while the other is grounded. When energized, a driving electric field is formed between the first and second electrodes. The arrowed line between the first and second electrodes in the diagram represents the electric field distribution. The diagram on the right is an enlarged view of the dashed circle portion of the diagram on the left, and it shows the refractive index ellipsoid, representing the change in the refractive index of the electro-optic medium in the phase adjustment unit. When no power is applied, the refractive index ellipsoid is essentially circular, as shown by the dashed line in the right diagram, with a refractive index of n. When the electrodes are energized, the refractive index ellipsoid is elongated, and the refractive index of the electro-optic medium becomes n+δn.

[0101] The electrode 30 can also be designed as a multi-layer architecture; see [reference needed]. Figures 20 to 23 The embodiments shown are as follows.

[0102] Figure 20 This is a schematic diagram of a multi-layered electrode 30. For a multi-layered electrode 30, "multi-layered" refers to at least two layers, and both the first electrode 31 and the second electrode 32 are planar, and along a first direction (e.g., ...). Figure 20 The first electrode 31 and the second electrode 32 are arranged in alternating layers (in the direction indicated by the double-headed arrows). The first direction is the direction in which the lower laparoscope, the cavity layer, and the upper laparoscope are arranged in alternating layers. The first direction can be understood as the direction perpendicular to the backplate. The first electrode 31 and the second electrode 32 are not located in the same layer, but are formed in different layers of the phase adjustment unit. It can be understood that each first electrode 31 and the second electrode 32 is a film structure, distributed in a planar manner in a certain layer of the cavity layer or a certain layer of the upper laparoscope. Different electrodes 30 are located in different layers. Moreover, the first electrode 31 and the second electrode 32 are arranged in alternating layers, that is, the second electrode 32 is disposed in the layer structure adjacent to one of the first electrodes 31, and one of the first electrodes 31 can be sandwiched between two adjacent second electrodes 32. The first electrical connection part 41 is electrically connected to the first electrode 31, and the second electrical connection part 42 is electrically connected to the second electrode 32, as shown. Figure 20 As shown, the first electrode 31 and the second electrode 32 partially overlap. The left edge region of the first electrode 31 does not overlap with the second electrode 32, and the right edge region of the second electrode 32 does not overlap with the first electrode 31. The first connecting portion 41 is connected to the leftmost edge of the first electrode 31, and the second connecting portion is connected to the rightmost edge of the second electrode 32. In summary: the portion of the first electrode 30 that does not overlap with the second electrode 30 is connected to the first connecting portion 41, and the portion of the second electrode 30 that does not overlap with the first electrode 30 is connected to the second connecting portion 42. The first electrode 31 and the second electrode 32 can be parallel layer structures.

[0103] See Figure 21 In one possible implementation, the electrode 30 is located within the cavity layer 22, and both the first electrode 31 and the second electrode 32 are disposed within the cavity layer 22. The advantage of fabricating the electrode 30 within the cavity layer 22 is that the fabrication process is relatively simple. Because the cavity layer 22 is made of a single material, there is no need to consider whether it generates transmittance or reflectance. For the cavity layer 22, transmittance is controlled by the material itself, not by its specific structure. Although the electrode 30 alters the structure of the cavity layer 22, its impact on transmittance is minimal because transmittance is controlled by the material of the cavity layer 22 itself. Figure 21 The lower endoscope 21 and cavity layer 22 shown are of different sizes in order to illustrate the structure of electrode 30. Figure 21 Only part of cavity layer 22 and part of the upper endoscope 23 are shown. Figure 21 The displayed status does not indicate that the dimensions of the lower laparoscope 21 and the cavity layer 22 in the phase adjustment unit are different.

[0104] Figure 21In the illustrated embodiment, a specific architecture is as follows: the cavity layer 22 includes alternating layers of two ITO films and two LiNbO3 films, specifically one LiNbO3 film, one ITO film, one LiNbO3 film, and one ITO film, in an alternating stacked distribution. In other embodiments, the cavity layer 22 can have three, four, or more layers, with adjacent layers made of different materials. The ITO film serves as the electrode 30, and the LiNbO3 film serves as the electro-optic medium between the electrodes 30. The thickness of each LiNbO3 film layer is 400 nm, and the thickness of each ITO film layer is 50 nm. The length (perpendicular to the paper) of the ITO film is 4 μm, and the width (parallel to the paper) is 2 μm. The odd-numbered ITO films (1, 3) (forming the first electrode) are connected to the vertical metal via (i.e., the first electrical connection) on the left; the even-numbered ITO film (2) (forming the second electrode) is connected to the vertical metal via (i.e., the second electrical connection) on the right. The region between ITO thin films is defined as the interlayer, and the polarization directions of the LiNbO3 thin films between adjacent layers are opposite.

[0105] Figure 21 In the illustrated embodiment, the upper cavity mirror 23, which faces away from the cavity layer 22 (i.e., the phase adjustment unit faces away from the backplate), has a protruding structure 70. This protruding structure 70 is formed on the top layer of the upper cavity mirror 23, or it can be understood as the protruding structure 70 being located on the side of the upper cavity mirror 23 facing away from the cavity layer 22; that is, the protruding structure 70 is a structure independent of the upper cavity mirror 23. The arrangement of the protruding structure 70 enables the phase adjustment unit to form an asymmetric architecture, used to suppress the modulation of the intensity of the optical signal, making the spatial light modulator provided in this application tend towards pure phase modulation. Figure 21 The protruding structure 70 shown is cuboid in shape, but it can also be in other shapes, such as cylindrical, blocky, spherical, etc. Figure 21 In the illustrated embodiment, the first electrical connection portion 41 and the second electrical connection portion 42 are located on opposite sides of the electrode 30. In this embodiment, the electrode 30 includes two first electrodes 31 and two second electrodes 32.

[0106] See Figure 22 In this embodiment, electrode 30 is fabricated inside the upper endoscope 23, based on the same principle as the fabrication of electrode 30 in cavity layer 22. In this embodiment, electrode 30 includes two first electrodes 31 and one second electrode 32. A first electrical connection portion 41 is electrically connected to the two first electrodes 31, and a second electrical connection portion 42 is electrically connected to the second electrode 32. Figure 21 The same implementation method is shown. In this embodiment, the surface of the upper endoscope 23 facing away from the cavity layer is also provided with a protruding structure 70.

[0107] See Figure 23In this embodiment, part of the electrode 30 is fabricated within the cavity layer 22, and part of the electrode 32 is fabricated within the upper endoscope 23. Specifically, as... Figure 23 As shown, the cavity layer 22 includes a first electrode 31 and a second electrode 32, and the upper endoscope 23 also includes a first electrode 31 and a second electrode 32. A first electrical connection 41 is electrically connected to all the first electrodes 31, and a second electrical connection 42 is electrically connected to all the second electrodes 32. Figure 21 The same implementation method is shown. In this embodiment, the surface of the upper endoscope 23 facing away from the cavity layer is also provided with a protruding structure 70.

[0108] In embodiments where the electrode 30 is located outside the surface of the upper laparoscope 23 (i.e., the electrode 30 of the single-layer structure is located in a layer within the upper laparoscope 23, a layer within the cavity layer 22, or a layer between the upper laparoscope 23 and the cavity layer 22), the surface of the upper laparoscope 23 facing away from the cavity layer 22 may also have a protruding structure (similar to...). Figures 21-23 The prominent structure shown also serves to make the phase adjustment unit 20 form an asymmetric architecture to suppress the modulation of the intensity of the optical signal, so that the spatial light modulator provided in this application tends to pure phase modulation.

[0109] In one possible implementation, for a multi-layered electrode structure, the number of first electrodes 30 and the number of second electrodes 30 are two or more. Since the first and second electrodes 30 generate an electric field when energized, setting the number of electrodes 30 to two or more allows for the generation of the required electric field using a smaller voltage. The number of first or second electrodes 30 can be controlled to 2-3 layers, because too many layers, such as more than 3, are difficult to manufacture. Therefore, the maximum number of electrode layers can be 6, with 3 layers for the first electrode and 3 layers for the second electrode.

[0110] The manufacturing process for each electrode layer 30 can be as follows:

[0111] The sputtering process is used to fabricate an electrode layer on the surface of a certain layer of the phase adjustment unit by sputtering. The electrode layer can be made of doped silicon.

[0112] The photolithography process involves coating a photoresist layer onto an electrode layer and then using the photolithography process to form a preset pattern from the photoresist layer.

[0113] An etching process is used to form the preset pattern on the electrode layer;

[0114] Planarization is a process used to flatten patterned electrodes. This can be achieved through polishing, such as chemical mechanical polishing.

[0115] The number of layers of the first electrode 31 and the second electrode 32 is not necessarily the same. For example, in one possible implementation, the electrode 30 includes one layer of the first electrode 31 and two layers of the second electrode 32, or two layers of the second electrode 32 and three layers of the first electrode 31.

[0116] Please refer to the schematic diagram of the electric field distribution and refractive index variation of the multilayer electrode 30. Figure 25 , Figure 25 The diagram schematically illustrates the architecture of two first electrodes and one second electrode. The two first electrodes are connected to the reference voltage of the driving circuit, and the second electrode is grounded. When energized, a driving electric field is formed in the interlayer between the two sides of the second electrode, and the driving electric fields in the two interlayers are in opposite directions.

[0117] The first electrical connection portion 41 and the second electrical connection portion 42 include a pad and a conductive portion connecting the pad and the drive circuit. The pad can be located in the same layer structure as the electrode 30, and the conductive portion can be in the form of a via lead. Specifically, during the manufacturing process, a via can be formed between the layer structure where the pad is located and the back plate 110. A metal wire or a metal conductive pillar can be provided in the via, or a metal layer can be formed on the inner wall of the via by electroplating to form the conductive portion.

[0118] In the spatial light modulator provided in this application, the electrode 30 and the electrical connection portion 40 connecting the electrode 30 and the driving circuit are both integrated within the phase correction unit. That is, during the fabrication of the phase correction unit, the electrode 30 and the electrical connection portion 40 can be fabricated simultaneously within the phase correction unit. The electrode 30 and the electrical connection portion 40 do not need to be fabricated separately outside the phase correction unit fabrication step, nor do they occupy space outside the phase correction unit. In this case, the phase correction units can be seamlessly connected as a whole. Furthermore, the electric field generated when the electrode 30 is energized is directly formed within the phase correction unit without loss, and the required electric field strength can be generated using a relatively small voltage.

[0119] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A spatial light modulator, characterized in that, include: Back panel, with built-in drive circuitry; The phase adjustment unit includes a lower cavity mirror, a cavity layer, and an upper cavity mirror, which are stacked sequentially on the back plate, with the lower cavity mirror located between the cavity layer and the back plate; The electrode includes a first electrode and a second electrode that are insulated from each other. The electrode is located inside or on the surface of the phase adjustment unit and on the side of the lower endoscope away from the back plate. The first electrode includes a first main line and at least two first branches extending from one side of the first main line. The second electrode includes a second main line and at least two second branches extending from one side of the second main line. The first main line and the second main line are arranged opposite to each other, and the first branches and the second branches form an interdigital structure. and An electrical connection portion electrically connects the electrode and the driving circuit to form a driving electric field between the first electrode and the second electrode, thereby adjusting the refractive index of the phase adjustment unit; The phase adjustment unit has a protruding structure on the surface opposite to the back plate, and the protruding structure is used to suppress intensity modulation of the optical signal.

2. The spatial light modulator according to claim 1, characterized in that... The driving circuit, the phase adjustment unit, the electrode, and the connection portion together constitute a pixel unit. The spatial light modulator includes multiple pixel units, which are arranged in an array. The phase adjustment units of adjacent pixel units are seamlessly connected.

3. The spatial light modulator according to claim 1 or 2, characterized in that, The electrodes are arranged on the first surface. The first surface is the surface of the upper endoscope that faces away from the cavity layer; or The phase adjustment unit includes multiple layer structures stacked sequentially, and the first surface is the surface of one of the layer structures.

4. The spatial light modulator according to claim 3, characterized in that, The first branch and the second branch are in a straight line; or, the first branch and the second branch are in a curved line.

5. The spatial light modulator according to claim 3, characterized in that, The electrical connection includes a first connection and a second connection that are insulated from each other. The first connection is connected to the first main line, and the second connection is connected to the second main line. The first connection and the second connection are distributed on opposite sides of the electrode.

6. The spatial light modulator according to claim 3, characterized in that, The first electrode and the second electrode extend side by side from a first position on the first surface to a second position on the first surface.

7. The spatial light modulator according to claim 6, characterized in that, The electrical connection includes a first connection and a second connection that are insulated from each other. Both the first connecting portion and the second connecting portion are located at the first position, which is located at the outer edge of the electrode.

8. The spatial light modulator according to claim 1 or 2, characterized in that, The lower laparoscope, the cavity layer, and the upper laparoscope are stacked sequentially along a first direction, and the first electrode and the second electrode are alternately stacked in the first direction.

9. The spatial light modulator according to claim 8, characterized in that, The electrode is located within the cavity layer.

10. The spatial light modulator according to claim 9, characterized in that, The electrical connection includes a first connection and a second connection that are insulated from each other. The first electrode and the second electrode partially overlap. The portion of the first electrode that does not overlap with the second electrode is connected to the first connection, and the portion of the second electrode that does not overlap with the first electrode is connected to the second connection.

11. The spatial light modulator according to claim 8, characterized in that, The number of the first electrode is two or more, and the number of the second electrode is two or more.

12. The spatial light modulator according to claim 1 or 2, characterized in that, The electrode is disposed on the surface of the upper cavity mirror away from the cavity layer, and the surface of the electrode is provided with a plurality of micropillar structures, which are used to suppress intensity modulation of the optical signal.

13. The spatial light modulator according to claim 1 or 2, characterized in that, The electrodes are disposed on the surface of the upper laminar mirror away from the cavity layer. An electro-optic medium is provided between the first electrode and the second electrode, or an electro-optic medium is provided between the first electrode and the second electrode and around the electrodes.

14. A wavelength selective switch, characterized in that, The device includes an optical fiber array, a main lens, and a spatial light modulator as described in any one of claims 1 to 13. The light beam detected by the optical fiber array is transformed into collimated light after passing through the main lens. The collimated light enters the spatial light modulator, which is used to reflect and deflect the collimated light to form reflected light. The reflected light is focused onto the optical fiber array by the main lens.

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