LCOS device and light adjustment apparatus

Abstract

An LCOS device and a light adjustment apparatus, relating to the technical field of light. In the LCOS device, a first film layer is configured to receive a light beam incident at a first angle and transmit the light beam to a second film layer; the second film layer is configured to enable the light beam passing through the first film layer to be incident on the first film layer at a second angle; the first film layer is further configured to reflect, to the second film layer, the light beam that sequentially passes through the first film layer and the second film layer; the second film layer is further configured to enable the light beam that sequentially passes through the first film layer, the second film layer, and the first film layer to be incident on the first film layer at the first angle; the first film layer is further configured to output, from a side away from the second film layer, the light beam that sequentially passes through the first film layer, the second film layer, the first film layer, and the second film layer; and a liquid crystal layer is configured to perform phase adjustment on the light beam transmitted between the first film layer and the second film layer under an action of an electric field. The present application can improve the speed at which an LCOS device adjusts the transmission direction of a light beam, and is applicable to LCOS devices.

Description

LCOS devices and light adjustment devices

[0001] This application claims priority to Chinese patent application filed on January 22, 2025, with application number 202510112896.0 and entitled "LCOS device and light adjustment device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optical technology, and in particular to an LCOS device and an optical adjustment device. Background Technology

[0003] A wavelength selective switch (WSS) is a common device in optical network systems. A WSS has an input port and multiple output ports, and can switch the light input at the input port to any output port.

[0004] Liquid crystal on silicon (LCOS device) is an important component of WSS. An LCOS device includes a liquid crystal layer, which can adjust the phase of the light beam incident on the LCOS device under the action of an electric field, so as to adjust the transmission direction of the light beam.

[0005] The speed at which an LCOS device adjusts the direction of light beam propagation is negatively correlated with the thickness of the liquid crystal layer. However, in related technologies, the thickness of the liquid crystal layer is relatively thick, resulting in a lower speed at which the LCOS device adjusts the direction of light beam propagation. Summary of the Invention

[0006] This application provides an LCOS device and an optical adjustment apparatus, which can solve the problem of low adjustment speed of the beam transmission direction by LCOS devices in related technologies. The solution provided by this application is as follows.

[0007] In a first aspect, an LCOS device is provided, comprising: a first film layer and a second film layer, and a liquid crystal layer located between the first film layer and the second film layer; wherein the first film layer is used to receive a light beam incident at a first angle from a side away from the second film layer, and transmit the light beam to the second film layer; the second film layer is used to incident the light beam passing through the first film layer onto the first film layer at a second angle, the first angle being different from the second angle; the first film layer is also used to reflect the light beam passing sequentially through the first film layer and the second film layer to the second film layer; the second film layer is also used to incident the light beam passing sequentially through the first film layer, the second film layer, and the first film layer onto the first film layer at the first angle; the first film layer is also used to output the light beam passing sequentially through the first film layer, the second film layer, the first film layer, and the second film layer from a side away from the second film layer; and the liquid crystal layer is used to perform phase adjustment on the light beam transmitted between the first film layer and the second film layer under the action of an electric field.

[0008] The LCOS device provided in this application includes a liquid crystal layer and a first film layer and a second film layer located on opposite sides of the liquid crystal layer. By designing the first and second film layers, a light beam incident at a first angle is transmitted into the LCOS device and travels back and forth twice between the first and second film layers, achieving four passes through the liquid crystal layer before output. This enables phase adjustment of the light beam after passing through the liquid crystal layer four times. Given a fixed phase adjustment amount, the LCOS device provided in this application can achieve this fixed phase adjustment amount using a thinner liquid crystal layer. Furthermore, since the switching speed of the liquid crystal in the LCOS device is negatively correlated with the thickness of the liquid crystal layer, the LCOS device provided in this application has a higher switching speed, resulting in a higher switching speed in the WSS (Wide Side Switch) containing the LCOS device. For example, in related technologies, the light beam passes through the liquid crystal layer twice. Given a fixed phase adjustment amount, compared to LCOS devices in related technologies, the LCOS device provided in this application has a halved thickness of the liquid crystal layer, resulting in a fourfold increase in the switching speed of the liquid crystal in the LCOS device.

[0009] Furthermore, as the thickness of the liquid crystal layer decreases in the embodiments of this application, the impact of the backflow effect on the switching speed of the liquid crystal also decreases.

[0010] Furthermore, given a fixed liquid crystal layer thickness, the LCOS device provided in this application embodiment can perform more phase adjustments on the light beam. For example, compared to LCOS devices in related technologies, the phase adjustment amount of the LCOS device provided in this application embodiment is doubled.

[0011] The first and second angles mentioned above can be implemented in various ways. For example, in one alternative implementation, the first angle is less than 90 degrees, and the second angle is 90 degrees. When the first angle A is less than 90 degrees, the first angle A can be any acute angle such as 20 degrees, 25 degrees, 30 degrees, or 40 degrees.

[0012] The aforementioned first film layer 01 can be implemented using any of a variety of optional implementation methods. In one optional implementation method of the first film layer 01, the first film layer includes: multiple first sub-film layers and multiple second sub-film layers; the first sub-film layers and second sub-film layers are arranged alternately in the thickness direction of the first film layer; the refractive indices of the first sub-film layers and the second sub-film layers are different. For example, the material of the first sub-film layer 011 includes silicon dioxide (SiO2), and the material of the second sub-film layer 012 includes tantalum pentoxide (Ta2O5).

[0013] When the first film layer includes multiple first sub-film layers and multiple second sub-film layers, the first film layer can also be used to receive and reflect a light beam incident at a second angle from the side away from the second film layer. The light beam incident at a second angle from the side of the first film layer away from the second film layer can be referred to as the second light beam, and the light beam incident at a first angle from the side of the first film layer away from the second film layer in the aforementioned embodiments can be referred to as the first light beam. Because the first film layer reflects the second light beam, the second light beam cannot be transmitted to the LCOS device provided in this application embodiment, making the optical paths of the second light beam and the first light beam different, thus reducing crosstalk caused by the second light beam to the first light beam. The wavelength range of the second light beam can be the same as or different from the wavelength range of the first light beam.

[0014] The second film layer described above can be implemented using any of a variety of alternative implementation methods. In one alternative implementation method, the second film layer includes a blazed grating layer. In another alternative implementation method, the second film layer includes a metasurface structure layer.

[0015] The wavelength of the light beam can be any wavelength. For example, the wavelength of the light beam can belong to the C+L band, where the wavelength range of the C band is 1530 nm to 1565 nm, and the wavelength range of the L band is 1565 nm to 1625 nm. Therefore, the wavelength of the light beam is greater than or equal to 1530 nm and less than or equal to 1625 nm. Of course, the wavelength of the light beam can also be less than 1530 nm or greater than 1625 nm; this application does not limit this.

[0016] Furthermore, the LCOS device provided in this application embodiment may also include a component for applying an electric field to the liquid crystal layer. For example, the LCOS device further includes: a transparent electrode layer, a bottom electrode layer, and a driving circuit layer; the transparent electrode layer is located on the side of the first film layer away from the second film layer, the bottom electrode layer is located on the side of the second film layer away from the first film layer, and the driving circuit layer is located on the side of the bottom electrode layer away from the second film layer; the driving circuit layer is used to: apply a voltage to the transparent electrode layer and the bottom electrode layer to form an electric field between the transparent electrode layer and the bottom electrode layer. The component for applying an electric field to the liquid crystal layer includes the transparent electrode layer, the bottom electrode layer, and the driving circuit layer.

[0017] Optionally, the surface of the bottom electrode layer near the liquid crystal layer is a reflective surface. For example, the bottom electrode may be made of metal to give it this reflective surface; or, the bottom electrode layer may include a base electrode layer and a reflective layer, with the reflective layer located between the base electrode layer and the liquid crystal layer, and the reflective surface being the surface of the reflective layer near the liquid crystal layer. The reflective surface of the bottom electrode layer can reflect the light beam transmitted through the second film layer, thereby improving the light beam utilization rate of the LCOS device provided in this application embodiment and reducing light leakage of the LCOS device.

[0018] Secondly, a light adjustment device is provided, comprising: a beam providing component, and any of the LCOS devices provided in the embodiments of this application, wherein the beam providing component is used to provide a beam, and the LCOS device is used to perform phase adjustment on the beam provided by the beam providing component.

[0019] For example, the optical adjustment device may be a WSS, in which case the beam providing component is the input port of the WSS, and the WSS also includes multiple output ports; the LCOS device is used to perform phase adjustment on the beam provided by the input port so that the beam is transmitted to any of the multiple output ports. Attached Figure Description

[0020] Figure 1 is a schematic diagram of the structure of an LCOS device provided in an embodiment of this application;

[0021] Figure 2 is a schematic diagram of a liquid crystal in a non-rotating state provided in an embodiment of this application;

[0022] Figure 3 is a schematic diagram of a liquid crystal rotation state provided in an embodiment of this application;

[0023] Figure 4 is a schematic diagram of a liquid crystal blazed grating provided in an embodiment of this application;

[0024] Figure 5 is a schematic diagram of a descent return zone provided in an embodiment of this application;

[0025] Figure 6 is a schematic diagram of another LCOS device provided in an embodiment of this application;

[0026] Figure 7 is a schematic diagram of a light beam passing through a liquid crystal layer for the first time according to an embodiment of this application;

[0027] Figure 8 is a schematic diagram of a light beam passing through a liquid crystal layer for the second time according to an embodiment of this application;

[0028] Figure 9 is a schematic diagram of a light beam passing through a liquid crystal layer for the third time according to an embodiment of this application;

[0029] Figure 10 is a schematic diagram of a light beam passing through a liquid crystal layer for the fourth time according to an embodiment of this application;

[0030] Figure 11 is a schematic diagram of the structure of a first membrane layer provided in an embodiment of this application;

[0031] Figure 12 is a schematic diagram of the transmittance of a first film layer to light beams incident at different angles according to an embodiment of this application;

[0032] Figure 13 is a schematic diagram of a blazed grating layer provided in an embodiment of this application;

[0033] Figure 14 is a schematic diagram of a metasurface structure layer provided in an embodiment of this application;

[0034] Figure 15 is a schematic diagram of another LCOS device provided in an embodiment of this application. Detailed Implementation

[0035] This application provides a WSS, which includes one or more inlet ports, multiple outlet ports, and a liquid crystal on silicon (LCOS) device. The LCOS device is used to adjust the phase of a light beam from the inlet port so that the light beam is transmitted to any one of the multiple outlet ports.

[0036] The LCOS device in this application embodiment is a phase-type LCOS device. A phase-type LCOS device is a liquid crystal optical phased array device, which is a hybrid optoelectronic chip composed of a silicon-based circuit backplane and liquid crystal optical elements. It can achieve high-resolution spatial light phase modulation.

[0037] The structure of an LCOS device is shown in Figure 1. The LCOS device includes a liquid crystal layer 11, a silicon-based backplane 12, and an indium tin oxide (ITO) transparent electrode cover plate 13. The silicon-based backplane 12 and the ITO transparent electrode cover plate 13 can apply a voltage (or an electric field) to the liquid crystal layer 11. When there is no voltage on the liquid crystal layer 11, as shown in Figure 2, the liquid crystals in the liquid crystal layer 11 are aligned in parallel. As the voltage on the liquid crystal layer 11 gradually increases to the threshold voltage Vc, as shown in Figure 3, the liquid crystals in the liquid crystal layer 11 will rotate at a certain angle, and different electric field intensities will cause the liquid crystals to rotate to different degrees.

[0038] By controlling the rotation of the liquid crystal, its refractive index can be changed, allowing the liquid crystal to modulate the phase of a light beam. Utilizing this property, a voltage can be applied to the liquid crystal layer through a silicon-based backplane and an ITO transparent electrode cover plate to control the liquid crystal layer to simulate a stepped blazed grating with a controllable wedge angle (as shown in Figure 4). The effect of the stepped blazed grating simulated by the liquid crystal layer on the light beam is equivalent to the effect of a grating on the light beam. By using this stepped blazed grating to adjust the phase of the light beam, the propagation direction of the beam can be controlled. Furthermore, the LCOS device only modulates the spatial phase of the incident light, without affecting the amplitude of the beam; therefore, the energy of the beam is theoretically not lost.

[0039] WSS can be applied in all-optical communication networks, such as in reconfigurable optical add / drop multiplexers (ROADMs) to control the transmission paths of light at different wavelengths within the ROADM. WSS using LCOS devices supports a higher number of ports, significantly increasing the transmission capacity of all-optical communication networks.

[0040] Furthermore, with the evolution of communication technology, the requirements for optical layer protection switching have become more explicit. Optical layer protection switching refers to the process of transferring the optical signal from the working optical path to a fault-free protection optical path when the working optical path for optical signal transmission fails, thereby ensuring the continued transmission of the optical signal. Optical layer protection switching requires the WSS (Wireless Switching Shield) to complete the port switching of the optical signal within milliseconds. In other words, optical layer protection switching requires the WSS to switch the optical signal from one port to another within milliseconds, thus achieving uninterrupted service and seamless user experience. Therefore, to meet this requirement, the switching speed of the WSS needs to be significantly improved. Thus, how to achieve fast switching has always been a crucial problem that LCOS devices and related application fields have been striving to solve.

[0041] The improvement in the switching speed of WSS depends on the improvement in the speed at which the LCOS device adjusts the beam transmission direction. The improvement in the speed at which the LCOS device adjusts the beam transmission direction depends on the speed at which the liquid crystal in the LCOS device switches from the unrotated state shown in Figure 2 to the rotated state shown in Figure 3 (referred to as the liquid crystal switching speed).

[0042] On the one hand, the switching speed of liquid crystal in LCOS devices is negatively correlated with the viscosity coefficient of liquid crystal materials. However, the reduction of viscosity coefficient often depends on new liquid crystal materials. Therefore, the space for reducing viscosity coefficient is limited, which limits the improvement of the switching speed of liquid crystal in LCOS devices, and also limits the improvement of the switching speed of WSS.

[0043] On the other hand, the switching speed of liquid crystal in LCOS devices is negatively correlated with the thickness of the liquid crystal layer. However, in related technologies, there is a theoretical lower limit to the thickness of this liquid crystal layer, resulting in a relatively thick layer and a low switching speed in LCOS devices, leading to a slow switching speed of the WSS (Wide Slip Switch). For example, the minimum phase modulation amount for the light beam in an LCOS device is proportional to the thickness of the liquid crystal layer. To meet the function of adjusting the transmission direction of the light beam, the LCOS device needs at least a phase modulation amount of 2π (pi). Therefore, the thickness of the liquid crystal layer also has a theoretical lower limit. Thus, traditional LCOS devices cannot significantly reduce the thickness of the liquid crystal layer to improve the switching speed of the liquid crystal and the switching speed of the WSS.

[0044] Furthermore, when a voltage is applied to the liquid crystal, its phase cannot be quickly reset from 2π back to 0. Instead, a falling back region is generated, as shown in Figure 5. The horizontal axis of Figure 5 represents the distance between any position in a series of positions arranged sequentially in a certain direction within the liquid crystal layer and the initial position, while the vertical axis represents the phase of the liquid crystal at that position. Moreover, the greater the thickness of the liquid crystal layer, the more pronounced the back region effect becomes, which significantly impacts the switching speed of the liquid crystal in LCOS devices. However, since there is a theoretical lower limit to the thickness of the liquid crystal layer, related technologies cannot reduce the impact of the back region effect on the switching speed of the liquid crystal by decreasing the thickness of the liquid crystal layer.

[0045] Based on this, this application provides an LCOS device. Under the same phase modulation amount (such as 2π), the thickness of the liquid crystal layer in the LCOS device can be reduced by half, and the switching speed of the WSS in which the LCOS device is located is four times faster than the switching speed of the WSS in related technologies.

[0046] For example, FIG6 is a schematic diagram of an LCOS device provided in an embodiment of the present application. As shown in FIG6, the LCOS device includes: a first film layer 01 and a second film layer 02, and a liquid crystal layer 03 located between the first film layer 01 and the second film layer 02.

[0047] In this embodiment, a light beam is transmitted between the first film layer 01 and the second film layer 02. When the light beam is transmitted between the first film layer 01 and the second film layer 02, it passes through the liquid crystal layer 03. The liquid crystal layer 03 is used to adjust the phase of the light beam transmitted between the first film layer 01 and the second film layer 02 under the action of an electric field.

[0048] For example, the first film layer 01 is used to receive a light beam incident at a first angle A from the side away from the second film layer 02, and transmit the light beam to the second film layer 02. The second film layer 02 is used to incident the light beam passing through the first film layer 01 at a second angle B onto the first film layer 01. The second angle B is different from the first angle A. The first film layer 01 is also used to reflect the light beam that passes through the first film layer 01 and the second film layer 02 in sequence to the second film layer 02; the second film layer 02 is used to incident the light beam that passes through the first film layer 01, the second film layer 02 and the first film layer 01 in sequence onto the first film layer 01 at the first angle A. The first film layer 01 is also used to output the light beam that passes through the first film layer 01, the second film layer 02, the first film layer 01 and the second film layer 02 in sequence from the side away from the second film layer 02.

[0049] Based on the functions of each of the above-mentioned film layers, it can be seen that the beam undergoes four phase adjustments in the LCOS device. These four phase adjustments are explained below.

[0050] (1) As shown in Figure 7, the light beam is incident from the side of the first film layer 01 away from the second film layer 02 at a first angle A. Then, the first film layer 01 transmits the light beam so that the light beam is transmitted to the second film layer 02. During this process, the light beam passes through the liquid crystal layer 03 for the first time and is phase-adjusted by the liquid crystal layer 03 for the first time.

[0051] After the phase of the light beam is adjusted by the liquid crystal layer 03, the transmission direction of the light beam will change. Therefore, after the first phase adjustment by the liquid crystal layer 03, the transmission direction of the light beam changes, so that the incident angle on the second film layer 02 when the light beam first reaches the second film layer 02 may be different from the first angle A.

[0052] (2) As shown in Figure 8, after the light beam reaches the side of the second film layer 02 close to the first film layer 01, the second film layer 02 will change the transmission direction of the received light beam so that the light beam is incident on the first film layer 01 at a second angle B. During this process, the light beam passes through the liquid crystal layer 03 for the second time and is phase-adjusted by the liquid crystal layer 03 for the second time.

[0053] After the second phase adjustment in the liquid crystal layer 03, the transmission direction of the light beam also changes. In this embodiment, the incident angle (second angle B) of the light beam on the first film layer 01 when it first transmits from the second film layer 02 to the first film layer 01, and the change in the transmission direction of the light beam during the second phase adjustment in the liquid crystal layer 03, can be designed to make the exit angle of the light beam on the second film layer 02 when it first transmits from the second film layer 02 to the first film layer 01.

[0054] Furthermore, in this embodiment, the second film layer 02 can be designed based on the incident angle of the light beam on the second film layer 02 when it is first transmitted to the second film layer 02, and the exit angle of the light beam on the second film layer 02 when it is first transmitted from the second film layer 02 to the first film layer 01.

[0055] (3) As shown in Figure 9, after the light beam reaches the first film layer 01 from the second film layer 02, it will be reflected by the first film layer 01 back to the second film layer 02. During this process, the light beam passes through the liquid crystal layer 03 for the third time and is phase-adjusted by the liquid crystal layer 03 for the third time.

[0056] (4) As shown in Figure 10, after the second beam reaches the second film layer 02, it will be incident on the first film layer 01 by the second film layer 02 at a first angle A. During this process, the beam passes through the liquid crystal layer 03 for the fourth time and is phase-adjusted by the liquid crystal layer 03 for the fourth time.

[0057] After the third and fourth phase adjustments of the liquid crystal layer 03, the transmission direction of the light beam changes. In this embodiment, the incident angle of the light beam on the second film layer 02 when it is transmitted to the first film layer 01 for the first time can be determined based on the exit angle of the light beam on the second film layer 02 when it is transmitted from the second film layer 02 to the first film layer 01 for the first time, and the change in the transmission direction of the light beam during the third phase adjustment in the liquid crystal layer 03.

[0058] This embodiment of the application can also determine the exit angle of the light beam on the second film layer 02 when it travels from the second film layer 02 to the first film layer 01 for the second time, based on the change in the transmission direction of the light beam during the fourth phase adjustment in the liquid crystal layer 03, and the incident angle (first angle A) of the light beam on the first film layer 01 when it travels from the second film layer 02 to the first film layer 01 for the second time. Furthermore, this embodiment of the application can also design the second film layer 02 based on the incident angle of the light beam on the second film layer 02 when it travels from the second film layer 02 to the first film layer 01 for the second time.

[0059] As can be seen, the light beam undergoes four phase adjustments within the LCOS device. Afterward, the beam is incident on the first film layer 01 at a first angle A and transmitted through the first film layer 01 to the side away from the second film layer 02. The output position of the light beam on the side of the first film layer 01 away from the second film layer 02 is related to these four phase adjustments. With each of these four phase adjustments, the output position of the light beam on the side of the first film layer 01 away from the second film layer 02 changes, thus enabling adjustment of the light beam's optical path.

[0060] For example, the beam is the beam that the LCOS device needs to modulate. The beam originates from the inlet port of the WSS and, after passing through the LCOS device, is transmitted to any one of the multiple outlet ports of the WSS. By adjusting the phase of the beam through the LCOS device, the output position of the beam on the side of the first film layer 01 away from the second film layer 02 is changed, thereby changing the outlet port to which the beam is transmitted among the multiple outlet ports of the WSS, thus achieving the switching of outlet ports.

[0061] Furthermore, the wavelength of the light beam can be any wavelength. For example, the wavelength of the light beam can belong to the C+L band, where the wavelength range of the C band is 1530 nm to 1565 nm, and the wavelength range of the L band is 1565 nm to 1625 nm. Therefore, the wavelength of the light beam is greater than or equal to 1530 nm and less than or equal to 1625 nm. Of course, the wavelength of the light beam can also be less than 1530 nm or greater than 1625 nm; this application does not limit this.

[0062] In summary, the LCOS device provided in this application includes a liquid crystal layer and a first film layer and a second film layer located on opposite sides of the liquid crystal layer. By designing the first and second film layers, a light beam incident at a first angle passes through the LCOS device and travels back and forth twice between the first and second film layers, achieving four passes of the light beam before output. This enables phase adjustment of the light beam after passing through the liquid crystal layer four times. Given a fixed phase adjustment amount, the LCOS device provided in this application can achieve this fixed phase adjustment amount using a thinner liquid crystal layer. Furthermore, since the switching speed of the liquid crystal in the LCOS device is negatively correlated with the thickness of the liquid crystal layer, the LCOS device provided in this application has a higher switching speed, resulting in a higher switching speed in the WSS (Wide Side Switch) of the LCOS device. For example, in related technologies, the light beam passes through the liquid crystal layer twice in the LCOS device. With a fixed phase adjustment amount, compared to the LCOS devices in related technologies, the LCOS device provided in this application has a halved thickness of the liquid crystal layer, resulting in a fourfold increase in the switching speed of the liquid crystal in the LCOS device.

[0063] Furthermore, as the thickness of the liquid crystal layer decreases in the embodiments of this application, the impact of the backflow effect on the switching speed of the liquid crystal also decreases.

[0064] Furthermore, given a fixed liquid crystal layer thickness, the LCOS device provided in this application embodiment can perform more phase adjustments on the light beam. For example, compared to LCOS devices in related technologies, the phase adjustment amount of the LCOS device provided in this application embodiment is doubled.

[0065] The aforementioned first angle A and second angle B can be implemented in several ways. For example, in one alternative implementation, the first angle A is less than 90 degrees, and the second angle B is 90 degrees. When the first angle A is less than 90 degrees, the first angle A can be any acute angle such as 20 degrees, 25 degrees, 30 degrees, or 40 degrees. Yet another alternative implementation is that both the first angle A and the second angle B are less than 90 degrees.

[0066] The first film layer 01 mentioned above can be implemented by any of a variety of optional implementation methods.

[0067] In one optional implementation of the first film layer 01, as shown in Figure 11, the first film layer 01 may include: multiple first sub-film layers 011 and multiple second sub-film layers 012. Figure 11 illustrates an example where the first film layer 01 includes four first sub-film layers 011 and four second sub-film layers 012. Optionally, the number of first sub-film layers 01 and the number of second sub-film layers 012 may not be four; for example, the number of first sub-film layers 01 and the number of second sub-film layers 012 may both be 3, 5, 6, 7, etc. The number of first sub-film layers 011 and the number of second sub-film layers 012 are the same.

[0068] In the thickness direction of the first film layer 01 (i.e., the arrangement direction of the first film layer 01 and the second film layer 02), the first sub-film layer 011 and the second sub-film layer 012 are arranged alternately. The sub-film layer of the first film layer 01 closest to the liquid crystal layer 03 can be either the first sub-film layer 011 or the second sub-film layer 012. In Figure 11, the first sub-film layer 011 is taken as the sub-film layer of the first film layer 01 closest to the liquid crystal layer 03. Therefore, from the liquid crystal layer 03 away from the second film layer 02, the four first sub-film layers 011 and the four second sub-film layers 012 in Figure 11 are arranged in the following order: first sub-film layer 011, second sub-film layer 012, first sub-film layer 011, second sub-film layer 012, first sub-film layer 011, second sub-film layer 012, first sub-film layer 011 and second sub-film layer 012.

[0069] The refractive index of the first sub-layer 011 is different from that of the second sub-layer 012. For example, the material of the first sub-layer 011 may include silicon dioxide (SiO2), and the material of the second sub-layer 012 may include tantalum pentoxide (Ta2O5). It is understood that the first sub-layer 011 and the second sub-layer 012 can be any two materials with different refractive indices. In this embodiment, silicon dioxide and tantalum pentoxide are used as examples. Of course, there are other possibilities for the materials of the first sub-layer 011 and the second sub-layer 012. For example, the material of the first sub-layer 011 may be silicon dioxide, and the material of the second sub-layer 012 may be silicon or titanium dioxide.

[0070] When the first film layer 01 includes multiple first sub-film layers 011 and multiple second sub-film layers 012, the first film layer 01 can also be used to receive and reflect a light beam incident at a second angle from the side away from the second film layer 02. The light beam incident at a second angle from the side of the first film layer 01 away from the second film layer 02 can be referred to as the second light beam, and in the aforementioned embodiments, the light beam incident at a first angle from the side of the first film layer 01 away from the second film layer 02 can be referred to as the first light beam. Because the first film layer 01 reflects the second light beam, the second light beam cannot be transmitted to the LCOS device provided in this application embodiment, making the optical paths of the second light beam and the first light beam different, thus reducing crosstalk caused by the second light beam to the first light beam. The wavelength range of the second light beam can be the same as or different from the wavelength range of the first light beam.

[0071] When the first film layer 01 includes multiple first sub-film layers 011 and multiple second sub-film layers 012, for a light beam incident on the first film layer 01, the first film layer 01 can reflect light in the beam with a wavelength greater than or equal to the cutoff wavelength and transmit light in the beam with a wavelength less than the cutoff wavelength. Furthermore, as the incident angle of the light beam on the first film layer 01 increases, the cutoff wavelength undergoes a blue shift (i.e., the cutoff wavelength gradually approaches the wavelength of blue light). Therefore, when both the wavelengths of the light beam and the second light beam belong to the C+L band, as shown in FIG12, this application can design the number and material properties of the first sub-film layers 011 and the second sub-film layers 012 to enable the first film layer 01, which includes multiple first sub-film layers 011 and multiple second sub-film layers 012, to transmit C+L band light beams incident at a first angle and reflect C+L band light beams incident at angles other than the first angle (such as the second angle).

[0072] It is understandable that the first membrane layer 01 can also be implemented in other ways. For example, the first membrane layer 01 may include at least three types of sub-membrane layers (such as three types of sub-membrane layers, four types of sub-membrane layers, etc.), and these at least three types of sub-membrane layers are also arranged alternately in the thickness direction of the first membrane layer 01. In this case, the first membrane layer includes multiple sub-membrane layer groups arranged sequentially along the thickness direction, and each sub-membrane layer group includes at least three different sub-membrane layers arranged sequentially in the thickness direction, with the sub-membrane layers and their arrangement order being the same in different sub-membrane layer groups.

[0073] The aforementioned second film layer 02 can be implemented using any of a variety of optional implementation methods.

[0074] In one optional implementation of the second film layer 02, the second film layer 02 includes a blazed grating layer. The structure of the blazed grating layer is shown in Figure 13. The surface of the blazed grating layer near the liquid crystal layer 03 is a sawtooth surface. The deflection angle of the light beam by the blazed grating layer is determined by the period of the sawtooth in the sawtooth surface, and the diffraction efficiency of the blazed grating layer for the light beam is determined by the shape of the sawtooth (such as the wedge angle of the sawtooth). By designing the period and shape of the sawtooth, the blazed grating layer can achieve the function of the second film layer 02.

[0075] In another optional implementation of the second film layer 02, the second film layer 02 includes a metasurface structure layer. As shown in Figure 14, the metasurface structure layer includes multiple subwavelength structures spaced apart in a plane parallel to the first film layer 01, with the maximum size of each subwavelength structure being smaller than the wavelength of the light beam. Figure 14 uses a columnar subwavelength structure as an example, but the subwavelength structures can also be other shapes, such as cubes or irregular shapes. The second film layer 02 can achieve the aforementioned effect on the light beam by adjusting its phase. By designing the size and arrangement of the subwavelength structures, the phase adjustment amount of the metasurface structure layer on the light beam can cover the range of 0 to 2π, thereby enabling the metasurface structure layer to achieve the aforementioned function of the second film layer 02.

[0076] The dimensions of multiple subwavelength structures can gradually change along a direction (called the gradient direction). For example, assuming the gradient direction is from left to right in Figure 14, and taking the diameter D of the first subwavelength structure in this gradient direction as 120 nm, the diameter of the subwavelength structures gradually increases along this gradient direction, with the diameter D of the last subwavelength structure in this gradient direction potentially being 174 nm. Furthermore, the spacing between the subwavelength structures (the distance between the centers of the subwavelength structures) can be 300 nm. And the subwavelength structures are distributed within a 3-micrometer region along this gradient direction.

[0077] Furthermore, the LCOS device provided in this application embodiment may also include components for applying an electric field to the liquid crystal layer. For example, as shown in FIG15, the LCOS device further includes a transparent electrode layer 04, a bottom electrode layer 05, and a driving circuit layer 06; the components for applying an electric field to the liquid crystal layer include the transparent electrode layer 04, the bottom electrode layer 05, and the driving circuit layer 06. The transparent electrode layer 04 may be an ITO layer.

[0078] For example, the transparent electrode layer 04 is located on the side of the first film layer 01 away from the second film layer 02, the bottom electrode layer 05 is located on the side of the second film layer 02 away from the first film layer 01, and the driving circuit layer 06 is located on the side of the bottom electrode layer 05 away from the second film layer 02. The driving circuit layer 06 is used to apply a voltage to the transparent electrode layer 04 and the bottom electrode layer 05 to form an electric field between them. Optionally, the transparent electrode layer 04 may also be located between the first film layer 01 and the liquid crystal layer 03. When the bottom electrode layer 05 is made of a transparent material, it may also be located between the liquid crystal layer 03 and the second film layer 02.

[0079] In this embodiment, the component that applies an electric field to the liquid crystal layer is an LCOS device. Optionally, the component may not be an LCOS device, but may be disposed outside the LCOS device. This embodiment does not limit this.

[0080] Optionally, the surface of the bottom electrode layer 05 near the liquid crystal layer 03 is a reflective surface. For example, the bottom electrode 05 may be made of metal to give it this reflective surface; or, the bottom electrode layer 05 may include a base electrode layer and a reflective layer, with the reflective layer located between the base electrode layer and the liquid crystal layer, and the reflective surface being the surface of the reflective layer near the liquid crystal layer. The reflective surface of the bottom electrode layer 05 can reflect the light beam transmitted through the second film layer 02, thereby improving the light beam utilization rate of the LCOS device provided in this embodiment and reducing light leakage of the LCOS device.

[0081] Optionally, the bottom electrode layer 05 may also be made of the same material as the transparent electrode layer 04 to reduce the fabrication complexity of the LCOS device. This application does not limit this aspect.

[0082] The first film layer 01 described above can be formed by deposition, therefore the first film layer 01 can be called a deposition layer. The function of the second film layer 02 described above is similar to that of a blazed grating, therefore the second film layer 02 can be called a grating layer or a grating functional layer. The transparent electrode layer 04 described above can be called a transparent electrode cover glass. The bottom electrode layer 05 and the driving circuit layer 06 described above can be collectively referred to as a silicon-based backplane or a backplane.

[0083] This application also provides a light adjustment device, which includes a beam providing component and any of the LCOS devices provided in this application. The beam providing component is used to provide a beam, and the LCOS device is used to perform phase adjustment on the beam provided by the beam providing component.

[0084] For example, the optical adjustment device may be a WSS, in which case the beam providing component is the input port of the WSS, and the WSS also includes multiple output ports; the LCOS device is used to perform phase adjustment on the beam provided by the input port so that the beam is transmitted to any of the multiple output ports.

[0085] As another example, the light adjustment device can be a spatial light modulator or a display device, in which case the beam providing component can be a light source for providing the beam.

[0086] In this application, the terms "first" and "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more. Different embodiments provided in this application can be referenced mutually, and this application does not limit the scope of the embodiments. The above descriptions are merely implementation methods of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered 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 silicon-based liquid crystal LCOS device, characterized in that, include: A first film layer and a second film layer, and a liquid crystal layer located between the first film layer and the second film layer; The first film layer is used to receive a light beam incident at a first angle from a side away from the second film layer, and to transmit the light beam to the second film layer; The second film layer is used to direct the light beam that has passed through the first film layer onto the first film layer at a second angle, wherein the first angle is different from the second angle; The first film layer is used to reflect the light beam that passes through the first film layer and the second film layer in sequence to the second film layer; The second film layer is used to direct the light beam that has passed through the first film layer, the second film layer and the first film layer in sequence to the first film layer at the first angle; The first film layer is used to output the light beam that passes through the first film layer, the second film layer, the first film layer and the second film layer in sequence from the side away from the second film layer; The liquid crystal layer is used to adjust the phase of the light beam transmitted between the first film layer and the second film layer under the action of an electric field.

2. The LCOS device according to claim 1, characterized in that, The first angle is less than 90 degrees, and the second angle is 90 degrees.

3. The LCOS device according to claim 2, characterized in that, The first angle is 20 degrees.

4. The LCOS device according to any one of claims 1 to 3, characterized in that, The first membrane layer includes: a plurality of first sub-membrane layers and a plurality of second sub-membrane layers; In the thickness direction of the first film layer, the first sub-film layer and the second sub-film layer are arranged alternately. The refractive index of the first sub-film layer is different from that of the second sub-film layer.

5. The LCOS device according to claim 4, characterized in that, The first sub-film layer is made of silicon dioxide, and the second sub-film layer is made of tantalum pentoxide.

6. The LCOS device according to any one of claims 1 to 5, characterized in that, The second film layer includes a blazed grating layer.

7. The LCOS device according to any one of claims 1 to 5, characterized in that, The second film layer includes a metasurface structure layer.

8. The LCOS device according to any one of claims 1 to 7, characterized in that, The wavelength of the light beam is greater than or equal to 1530 nanometers and less than or equal to 1625 nanometers.

9. The LCOS device according to any one of claims 1 to 8, characterized in that, The thickness of the liquid crystal layer is greater than or equal to 2 micrometers and less than or equal to 3 micrometers.

10. The LCOS device according to any one of claims 1 to 9, characterized in that, The LCOS device further includes: a transparent electrode layer, a bottom electrode layer, and a driving circuit layer; The transparent electrode layer is located on the side of the first film layer away from the second film layer, the bottom electrode layer is located on the side of the second film layer away from the first film layer, and the driving circuit layer is located on the side of the bottom electrode layer away from the second film layer; The driving circuit layer is used to: apply a voltage to the transparent electrode layer and the bottom electrode layer to form the electric field between the transparent electrode layer and the bottom electrode layer.

11. The LCOS device according to claim 10, characterized in that, The surface of the bottom electrode layer near the liquid crystal layer is a reflective surface.

12. A light adjustment device, characterized in that, include: A beam providing component and an LCOS device according to any one of claims 1 to 11, wherein the beam providing component is used to provide a beam and the LCOS device is used to perform phase adjustment on the beam provided by the beam providing component.

13. The light adjustment device according to claim 12, characterized in that, The light adjustment device is a wavelength selective switch (WSS), the beam providing component is an input port, and the WSS also includes multiple output ports; The LCOS device is used to adjust the phase of the beam provided by the beam providing component so that the beam is transmitted to any one of the plurality of output ports.

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