Optical switching system and method

Abstract

The invention discloses an optical switching system and method. The system comprises a collimation input optical fiber, a polarizer, a first ferroelectric optical switch, a first optical path sorting unit, a first quarter-wave plate, a second ferroelectric optical switch, a second optical path sorting unit and a collimation input optical fiber receiving array. Dynamic switching is achieved through the two stable states of the ferroelectric optical switch, compared with a traditional mechanical optical switch, the response speed is higher, the reliability is higher, port expansion can be achieved through the cascade ferroelectric optical switch and the optical path sorting unit, and therefore the optical communication optical switch can adapt to optical communication network applications of different scales.

Description

An optical switching system and method Technical Field

[0001] This invention relates to the field of optical communication technology, and more particularly to an optical switching system and method. Background Technology

[0002] As a core node in optical communication networks, the optical cross-connector plays a crucial role in the dynamic switching of multiple optical signals and the reconfiguration of the optical network. It can precisely distribute the optical channel signal or specific wavelength signal from any input port to any output port, enabling efficient communication between connected devices. The core components of this device include an optical cross-connect matrix, input / output interfaces, and a management and control module.

[0003] In traditional electrical switching architectures, signal processing requires optical-to-electrical-to-optical conversion, which introduces latency and severely hinders the efficiency of real-time tasks such as AI training by causing GPUs and other computing resources to wait for data. Simultaneously, optical-to-electrical-to-optical conversion consumes significant energy, making network equipment one of the main energy sources in data centers. As cluster size increases, power consumption and cooling costs grow exponentially. High-performance electrical switch chips are expensive, and building large-scale non-blocking networks requires stacking numerous devices, increasing both initial investment and cabling management complexity. Furthermore, high crosstalk and slow response time are performance bottlenecks in optical communication networks.

[0004] Optical switches are the core components of optical cross-connect matrices, acting as the "optical traffic police" in optical networks. They precisely select optical paths to switch and distribute signals, which is fundamental to the dynamic scheduling capabilities of optical cross-connects. Existing optical switching solutions have significant limitations. While traditional architectures based on wavelength-selective switches can achieve wavelength scheduling, their scalability is limited. Some mechanical optical switches, although offering low insertion loss, have slow response times.

[0005] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide an optical switching system and method to solve the problems of limited scalability and slow response speed of existing optical switching schemes.

[0007] The technical solution of the present invention is as follows: In a first aspect, the present invention provides an optical switching system, comprising: a collimated input fiber, a polarizer, a first ferroelectric optical switch, a first optical path sorting unit, a first quarter-wave plate, a second ferroelectric optical switch, a second optical path sorting unit, and a collimated input fiber receiving array; wherein, the collimated input fiber is located on the incident optical path of the polarizer and is used to connect to a laser source; the polarizer is located on the incident optical path of the first ferroelectric optical switch and is used to adjust the connected incident light into linearly polarized light and input it to the first ferroelectric optical switch; the first ferroelectric switch is used to convert the linearly polarized light into two orthogonally linearly polarized light states; the first optical path sorting unit ... connect the first ferroelectric optical switch into a laser source; the collimated input fiber is located on the incident optical path of the first ferroelectric optical switch and is used to connect the first ferroelectric optical switch into a laser source; the collimated input fiber is located on the incident optical path of the first ferroelectric optical switch and is used to connect the first ferroelectric optical switch into a laser source; the collimated input fiber is located on the incident optical path of the first ferroelectric optical switch and is used to connect the first ferroelectric optical switch into a laser source; the collimated input fiber is located on the incident optical path of the first ferroelectric optical switch and is used to connect the first ferroelectric optical switch into a laser source; the collimated input fiber is located on the incident optical path of the first ferroelectric optical switch and is used to connect the first ferroelectric optical The first quarter-wave plate is located on the incident light side and is used to convert two orthogonally linearly polarized light states into left-handed and right-handed circularly polarized light, which are then input into the first quarter-wave plate. The first quarter-wave plate is located on the incident light path of the second ferroelectric optical switch and is used to convert left-handed and right-handed circularly polarized light into linearly polarized light and input it into the second ferroelectric optical switch. The second ferroelectric optical switch is used to convert linearly polarized light into two orthogonally linearly polarized light states. The second optical path sorting unit is located on the incident light path of the collimated input fiber receiving array and is used to convert linearly polarized light into left-handed and right-handed circularly polarized light. The collimated input fiber receiving array is used to receive each circularly polarized light path.

[0008] In a further embodiment of the present invention, the first optical path sorting unit includes: a second quarter-wave plate and a first liquid crystal polarization grating; the second quarter-wave plate is located between the first ferroelectric optical switch and the first liquid crystal polarization grating, and is used to convert the two orthogonally linearly polarized light output by the first ferroelectric optical switch into left-handed circularly polarized light and right-handed circularly polarized light; the first liquid crystal polarization grating is used to output the left-handed circularly polarized light and right-handed circularly polarized light to the first quarter-wave plate.

[0009] In a further embodiment of the present invention, the second optical path sorting unit includes: a third quarter-wave plate and a second liquid crystal polarization grating; the third quarter-wave plate is located between the second ferroelectric optical switch and the second liquid crystal polarization grating, and is used to convert the orthogonally linearly polarized light output by the second ferroelectric optical switch into left-hand circularly polarized light and right-hand circularly polarized light; the second liquid crystal polarization grating is used to output the left-hand circularly polarized light and right-hand circularly polarized light to the collimated input fiber receiving array.

[0010] In a further embodiment of the present invention, the first ferroelectric optical switch and the second ferroelectric optical switch are controlled by a driving signal. By controlling the polarity switching of the driving signal, the incident linearly polarized light is converted into two orthogonally linearly polarized light states.

[0011] A further feature of the present invention is that when the first liquid crystal polarizing grating or the second liquid crystal polarizing grating is rotated by 90°, the one-dimensionally arranged output ports can be adjusted to a two-dimensionally distributed output port.

[0012] In a further embodiment of the present invention, the first ferroelectric optical switch includes: a conductive layer, an alignment layer, a liquid crystal molecule layer, and an encapsulation layer; the conductive layers are respectively located at the bottom and top of the first ferroelectric optical switch; the alignment layers are respectively located on one side of the top conductive layer and on one side of the bottom conductive layer; the liquid crystal molecule layer is located between the two alignment layers; the encapsulation layer is located between the two conductive layers and abuts against the alignment layer and the liquid crystal molecule layer.

[0013] In a further embodiment of the present invention, the conductive layer comprises: a glass substrate and a conductive thin film; the conductive thin film is disposed on the side of the glass substrate near the alignment layer.

[0014] A further embodiment of the present invention includes: a third ferroelectric optical switch, a fourth ferroelectric optical switch, a third optical path sorting unit, a fourth optical path sorting unit, a fourth quarter-wave plate, and a fifth quarter-wave plate; the fourth quarter-wave plate is located between the second optical path sorting unit and the third ferroelectric optical switch; the third optical path sorting switch is located between the third ferroelectric optical switch and the fifth quarter-wave plate; and the fourth ferroelectric optical switch is located between the fifth quarter-wave plate and the fourth optical path sorting unit.

[0015] In a further embodiment of the present invention, a plurality of collimated input fibers are provided, forming a collimated input fiber array; the optical switching system further includes a spliced ​​polarization grating obtained by splicing gratings of different periods in regions, the number of gratings of the spliced ​​polarization grating corresponding to the number of collimated fibers in the collimated input fiber array.

[0016] Secondly, the present invention also provides an optical switching method based on the optical switching system described above, comprising the steps of: controlling the polarity switching of the driving signals of the first ferroelectric optical switch and the second ferroelectric switch by a driving circuit to change the relative direction of the liquid crystal optical axis, thereby converting the incident linearly polarized light into two orthogonally linearly polarized light states; and controlling the first optical path sorting unit and the second optical path sorting unit by an electric field to output circularly polarized light of different polarization states to different ports, thereby realizing optical path sorting and port switching.

[0017] The present invention provides an optical switching system and method, the system comprising: a collimated input fiber, a polarizer, a first ferroelectric optical switch, a first optical path sorting unit, a first quarter-wave plate, a second ferroelectric optical switch, a second optical path sorting unit, and a collimated input fiber receiving array; wherein, the collimated input fiber is located on the incident optical path of the polarizer and is used to connect to a laser source; the polarizer is located on the incident optical path of the first ferroelectric optical switch and is used to adjust the connected incident light into linearly polarized light and input it to the first ferroelectric optical switch; the first ferroelectric switch is used to convert the linearly polarized light into two orthogonally linearly polarized states of light; the first optical path sorting unit is located on the incident optical path of the first quarter-wave plate, a first quarter-wave plate, a second ferroelectric optical switch, a second optical path sorting unit, and a collimated input fiber receiving array; wherein, the collimated input fiber is located on the incident optical path of the polarizer and is used to connect to a laser source; the polarizer is located on the incident optical path of the first ferroelectric optical switch and is used to adjust the connected incident light into linearly polarized light and input it to the first ferroelectric optical switch; the first ferroelectric optical switch is used to convert the linearly polarized light into two orthogonally linearly polarized states of light; the first optical path sorting unit is located on the incident optical path of the first quarter-wave plate, a first quarter-wave plate, a second ferroelectric optical switch, a second optical path sorting unit, and a collimated input fiber receiving array; wherein, the collimated input fiber is located on the incident optical path of the first ferroelectric optical switch and is used to connect to a laser source; the first ferroelectric optical switch ... The first quarter-wave plate, located on the incident light side, converts two orthogonally linearly polarized light states into left-handed and right-handed circularly polarized light, which are then input into the first quarter-wave plate. The first quarter-wave plate, situated on the incident light path of the second ferroelectric-optical switch, converts the left-handed and right-handed circularly polarized light into linearly polarized light and inputs it into the second ferroelectric-optical switch. The second ferroelectric-optical switch converts linearly polarized light into two orthogonally linearly polarized light states. The second optical path sorting unit, located on the incident light path of the collimated input fiber receiving array, converts linearly polarized light into left-handed and right-handed circularly polarized light. The collimated input fiber receiving array receives each path of circularly polarized light. This invention utilizes the two stable states of the ferroelectric-optical switch to achieve dynamic switching, offering faster response and higher reliability compared to traditional mechanical optical switches. Furthermore, by cascading ferroelectric-optical switches and optical path sorting units, port expansion can be achieved, thus adapting to optical communication network applications of different scales. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0019] Figure 1 is a schematic diagram of the optical switching system in one embodiment of the present invention.

[0020] Figure 2 is a morphological image of a uniformly oriented ferroelectric optical switching element sample under a transmission microscope in one embodiment of the present invention.

[0021] Figure 3 is a waveform diagram of a single ferroelectric liquid crystal switch under a driving voltage of 1kHz and ±6.5V in one embodiment of the present invention.

[0022] Figure 4 is a waveform diagram of the response of each output port when two ports of a 1×4 optical switching system switch to each other in one embodiment of the present invention.

[0023] Figure 5 is a topographic image of a liquid crystal polarization grating element sample under a transmission microscope in one embodiment of the present invention.

[0024] Figure 6 is a beam splitting effect diagram of circularly polarized light output by a single liquid crystal polarization grating (diffraction efficiency of 99%) in one embodiment of the present invention.

[0025] Figure 7 illustrates an embodiment of the present invention. Optical path diagram of the output port.

[0026] Figure 8 is a schematic diagram of the structure of a ferroelectric optical switch in one embodiment of the present invention.

[0027] Figure 9 is an exposure diagram of the orientation layer with phase-order design of the polarization grating in one embodiment of the present invention.

[0028] Figure 10 is a schematic diagram of the polarization state of the two-dimensional distributed output port when the second liquid crystal polarization grating is rotated 90 degrees in one embodiment of the present invention.

[0029] Figure 11 is a schematic diagram of a 4×4 optical switching system in one embodiment of the present invention.

[0030] Figure 12 is a schematic flowchart of an optical switching method in one embodiment of the present invention.

[0031] The labels in the attached diagram are as follows: 1. Collimating input fiber; 2. Polarizer; 3. First ferroelectric-optical switch; 31. Conductive layer; 311. Glass substrate; 312. Conductive thin film; 32. Alignment layer; 33. Liquid crystal molecule layer; 34. Encapsulation layer; 4. First optical path sorting unit; 41. Second quarter-wave plate; 42. First liquid crystal polarization grating; 5. First quarter-wave plate; 6. Second ferroelectric-optical switch; 7. Second optical path sorting unit; 71. Third quarter-wave plate; 72. Second liquid crystal polarization grating; 8. Collimating input fiber receiving array; 9. Third ferroelectric-optical switch; 10. Fourth ferroelectric-optical switch; 11. Third optical path sorting unit; 12. Fourth optical path sorting unit; 13. Fourth quarter-wave plate; 14. Fifth quarter-wave plate; 15. Collimating input fiber array; 16. Spliced ​​polarization grating. Detailed Implementation

[0032] This invention provides an optical switching system and method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0033] In the implementation methods and claims, unless otherwise specified in the text, the terms "a," "an," "the," and "the" may also include plural forms. If the embodiments of the present invention involve descriptions of "first," "second," etc., such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0034] It should be further understood that the term "comprising" as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when an element is referred to as "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements present. Furthermore, "connected" or "coupled" as used herein can include wireless connections or wireless coupling. The term "and / or" as used herein includes all or any of the units and all combinations thereof of one or more associatedly listed items.

[0035] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0036] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0037] The inventors discovered that optical switches are the core components of optical cross-connect matrices, acting as "optical traffic police" in optical networks. They precisely select optical paths to switch and distribute signals, fundamentally enabling the dynamic scheduling capabilities of optical cross-connects. Essentially, an optical switch is an optical device that physically switches or logically controls optical signals within optical transmission lines or integrated optical paths. Its core principle is to change the propagation path or on / off state of light through specific mechanisms, without requiring a light-to-electricity-to-light signal conversion process. In the data center field, scenarios such as large-scale AI model training and distributed computing have spurred massive data interaction demands. In AI supercomputing clusters centered around large-scale GPU clusters, the multi-level design of traditional electrical switching architectures leads to low communication efficiency. Optical switches, on the other hand, can directly route signals in the optical domain, providing low-latency, high-bandwidth interconnection channels for the cluster. Existing optical switching solutions have significant limitations. While traditional architectures based on wavelength selective switches can achieve wavelength scheduling, their scalability is limited and they rely on expensive M×N wavelength selective switch devices, which cannot meet the needs of progressive network upgrades. Some mechanical optical switches have the advantage of low insertion loss, but their response speed is slow. Electro-optical and thermo-optical switches are difficult to balance in terms of port density and stability, and cannot be adapted to large-scale application scenarios in backbone networks and data centers.

[0038] To address the aforementioned technical problems, this invention provides an optical switching system and method. The system includes: a collimated input fiber, a polarizer, a first ferroelectric optical switch, a first optical path sorting unit, a first quarter-wave plate, a second ferroelectric optical switch, a second optical path sorting unit, and a collimated input fiber receiving array. Dynamic switching is achieved using the two stable states of the ferroelectric optical switch, resulting in faster response speed and higher reliability compared to traditional mechanical optical switches. Furthermore, port expansion can be achieved through cascading ferroelectric optical switches and optical path sorting units, with relatively low cost, thus adapting to optical communication network applications of different scales.

[0039] Please refer to Figures 1 to 11 simultaneously. The present invention provides a preferred embodiment of an optical switching system and method.

[0040] In some embodiments, as shown in FIG1, the present invention provides an optical switching system, comprising: a collimated input fiber 1, a polarizer 2, a first ferroelectric optical switch 3, a first optical path sorting unit 4, a first quarter-wave plate 5, a second ferroelectric optical switch 6, a second optical path sorting unit 7, and a collimated input fiber receiving array 8. The collimated input fiber 1 is located on the incident optical path of the polarizer 2 and is used to connect to a laser source; the polarizer 2 is located on the incident optical path of the first ferroelectric optical switch 3 and is used to adjust the incoming incident light into linearly polarized light and input it to the first ferroelectric optical switch 3; the first ferroelectric switch is used to convert the linearly polarized light into two orthogonally linearly polarized light states; the first optical path sorting unit 4 is located on the incident light side of the first quarter-wave plate 5 and is used to convert the two orthogonally linearly polarized light states into left-handed circularly polarized light and right-handed circularly polarized light and input them to the first quarter-wave plate 5. The first quarter-wave plate 5 is located on the incident light path of the second ferroelectric optical switch 6, and is used to convert left-hand circularly polarized light and right-hand circularly polarized light into linearly polarized light and input it to the second ferroelectric optical switch 6; the second ferroelectric optical switch 6 is used to convert linearly polarized light into two orthogonal linearly polarized light states; the second optical path sorting unit 7 is located on the incident light path of the collimated input fiber receiving array 8, and is used to convert linearly polarized light into left-hand circularly polarized light and right-hand circularly polarized light; the collimated input fiber receiving array 8 is used to receive each path of circularly polarized light.

[0041] Specifically, ferroelectric optical switches refer to ferroelectric liquid crystal optical switches. Liquid crystals exhibit significant optical anisotropy. When a suitable electric field is applied to a transparent electrode structure holding the liquid crystal layer, the electric field exerts a torque on the permanent electric dipole moment of the molecules, driving the molecular orientation to reconfigure, such as changing from a twisted arrangement to a parallel arrangement, thus altering optical properties such as transmittance and polarization state. Ferroelectric liquid crystals are a special type of liquid crystal with a photoelectric response speed two to three orders of magnitude faster than nematic liquid crystals. Among them, electro-rotational ferroelectric liquid crystals can completely derotate the helical structure by applying forward and reverse voltages, obtaining bright and dark states with high orientation quality. Its alignment layer 32 can provide direction for the helical axis. The optimized anchoring energy is balanced with the helical elastic potential energy, allowing the liquid crystal cell to be driven to derotate with low voltage. When no voltage is applied, it maintains a partially derotated helical structure between the glass substrates. Electro-rotational ferroelectric liquid crystals can be used as fast-response optical switches for amplitude, phase, and polarization modulation. With a voltage less than 10V, the switching response time is less than 100 microseconds. It can function as two orthogonal circular polarization selectors with sub-millisecond response between a polarizer and a quarter-wave plate, enabling fast beam control when cascaded with a polarization grating.

[0042] Collimating optical fibers use optical elements such as lenses to convert diverging light emitted from the fiber into parallel light, reducing optical signal loss and distortion. A quarter-wave plate can switch between linearly polarized and circularly polarized light, while ferroelectric liquid crystals can act as high-speed polarization switches, rapidly switching the rotation direction of circularly polarized light incident on the liquid crystal polarization grating when paired with a quarter-wave plate. Polarizer 2 converts the incident laser source into linearly polarized light.

[0043] In this embodiment, the system input light source is a tunable laser source with a wavelength of 1310nm in the data center communication band. The collimating input fiber 1 connects the laser source to and inputs it to the polarizer 2. The polarizer 2 can convert the incident light into linearly polarized light and transmit it to the first ferroelectric optical switch 3. Under the control of the driving signal (the first ferroelectric optical switch 3 and the second ferroelectric optical switch 6 are controlled by the driving signal; by controlling the polarity switching of the driving signal, the incident linearly polarized light is converted into two orthogonal linearly polarized states), the first ferroelectric optical switch 3 can convert the incident linearly polarized light into two orthogonal linearly polarized states, enabling rapid switching of the linear polarization state. For example, when a beam of horizontally linearly polarized incident light passes through the first ferroelectric optical switch, the polarization direction of the light is parallel to the optical axis of the liquid crystal, so the polarization state remains unchanged. If the driving voltage is switched to the opposite polarity, the angle between the optical axis of the ferroelectric optical switch and the polarization direction of the incident light is 45°, and the horizontally linearly polarized light is converted into stable vertically linearly polarized light. Two linearly polarized lights with perpendicular polarization directions are converted into two stable circularly polarized lights with opposite rotation directions after passing through a quarter-wave plate. The frequency of the square wave signal is adjusted to meet the stable dwell time at the port, and the magnitude of the positive and negative levels is adjusted to meet the high-speed switching of the liquid crystal azimuth angle.

[0044] The first optical path sorting unit 4 converts the two orthogonally linearly polarized light emitted from the first ferroelectric optical switch 3 into left- and right-circularly polarized light, and then emits it to the first quarter-wave plate 5. The first quarter-wave plate 5 converts the two circularly polarized lights into linearly polarized light. The two linearly polarized lights obtained by the first quarter-wave plate 5 are incident on the second ferroelectric optical switch 6, which converts the two linearly polarized lights into two orthogonally polarized lights respectively. Subsequently, the second optical path sorting unit 7 converts the two orthogonally polarized lights into left- and right-circularly polarized lights, resulting in four circularly polarized lights, which are then output to different ports of the collimated input fiber receiving array 8, realizing optical path sorting and port switching. The light spot at the system output port can be detected by an infrared CCD camera, the output waveform is acquired by a photodetector and an oscilloscope, and the output power is detected by a spatial optical power meter. The free-space output light is matched with the mode field diameter of the optical fiber by a collimator, and after coupling, the power loss is measured at the output end of the single-mode fiber using a power meter, and communication tests are performed on the output of each fiber.

[0045] In the above technical solution, this invention utilizes two stable states of a ferroelectric optical switch to achieve rapid switching of dynamic linear polarization states. The microsecond-level response speed of the ferroelectric optical switch significantly improves port switching efficiency, making it suitable as a high-speed optical switch for high-speed optical communication or dynamic optical systems. The system achieves fully electrically controlled polarization modulation, is stable without mechanical movement, and can achieve dynamic switching without mechanical assistance, avoiding wear of mechanical components, improving reliability and lifespan. Compared with traditional mechanical optical switches, it has a faster response speed and higher reliability, meeting the high-speed and stable switching requirements of optical communication systems. Figure 2 shows the morphology of a uniformly oriented ferroelectric liquid crystal switch element sample under a transmission microscope. The molecular arrangement of the ferroelectric liquid crystal tends to be uniformly oriented under the action of an applied electric field. The morphology image can reveal the molecular arrangement of the liquid crystal, possible defects, and the uniformity of the liquid crystal layer. A uniformly oriented liquid crystal layer shows the consistency of the liquid crystal molecular arrangement, which helps to improve the switching speed and polarization state stability. If non-uniform arrangement or defects are observed, it may lead to slow response and increased device loss. If the image shows consistent contrast and texture, without obvious differences in brightness or stripes, it indicates that the orientation of the ferroelectric liquid crystal molecules is relatively uniform. This means that in the sample, the directores (major axis direction) of the liquid crystal molecules are roughly aligned in the same direction, which is beneficial for achieving stable performance and fast response characteristics of the ferroelectric liquid crystal switching element. Figure 3 shows the waveform of a single ferroelectric liquid crystal switch at 1kHz and ±6.5V driving voltage. The frequency of the square wave signal is adjusted to meet the port's stable dwell time, and the magnitude of the positive and negative levels is adjusted to meet the high-speed switching of the liquid crystal azimuth angle. As shown in Figure 4, the response waveforms of each output port when two ports of a 1×4 optical switching system switch to each other are shown. Due to device losses and driving voltage fluctuation errors, the response time increases to over 100 microseconds. The high-speed electro-optic modulation characteristics of ferroelectric liquid crystals enable optical switching systems to achieve high-speed port switching while ensuring stable output of port polarization states. This is crucial for accurate signal transmission and processing in high-speed optical communication networks. Furthermore, the output port can be flexibly selected by simply adjusting the polarity and amplitude of the electrical signal. The operation is convenient and can be expanded to multi-channel applications. Port expansion can be achieved by cascading ferroelectric optical switches and optical path sorting units. The number of ports can be flexibly increased or decreased according to actual needs, and the cost is relatively low, thus adapting to optical communication network applications of different scales.

[0046] In some embodiments, as shown in FIG1, the first optical path sorting unit 4 includes: a second quarter-wave plate 41 and a first liquid crystal polarization grating 42; the second quarter-wave plate 41 is located between the first ferroelectric optical switch 3 and the first liquid crystal polarization grating 42, and is used to convert the two orthogonally linearly polarized light output by the first ferroelectric optical switch 3 into left-handed circularly polarized light and right-handed circularly polarized light; the first liquid crystal polarization grating 42 is used to output the left-handed circularly polarized light and right-handed circularly polarized light to the first quarter-wave plate 5.

[0047] Further, the second optical path sorting unit 7 includes: a third quarter-wave plate 71 and a second liquid crystal polarization grating 72; the third quarter-wave plate 71 is located between the second ferroelectric optical switch 6 and the second liquid crystal polarization grating 72, and is used to convert the orthogonally linearly polarized light output by the second ferroelectric optical switch 6 into left-hand circularly polarized light and right-hand circularly polarized light; the second liquid crystal polarization grating 72 is used to output the left-hand circularly polarized light and right-hand circularly polarized light to the collimated input fiber receiving array 8.

[0048] In this embodiment, the first optical path sorting unit 4 and the second optical path sorting unit 7 have the same structure, both consisting of a quarter-wave plate and a liquid crystal polarization grating.

[0049] A liquid crystal polarization grating is a diffractive optical element that achieves selective beam splitting based on the polarization state of incident light. It can output circularly polarized light with different polarization directions to non-overlapping receivers. Figure 5 shows the morphology of a liquid crystal polarization grating element sample under a transmission microscope. Figure 6 shows the beam splitting effect of a single liquid crystal polarization grating (99% diffraction rate) outputting circularly polarized light. When the incident light is right-handed circularly polarized, it produces +1st order diffracted light, which is left-handed circularly polarized, after passing through the polarization grating. When the incident light is left-handed circularly polarized, it produces -1st order diffracted light, which is right-handed circularly polarized, after passing through the polarization grating. Therefore, by selecting the polarity of the driving voltage of the ferroelectric liquid crystal cell, the rotation direction of the output circularly polarized light can be selected and the high-speed switching of the receiver port can be achieved, realizing the function of light exchange. For example, when the diffraction angle of the first polarization grating is 2.5 degrees and the diffraction angle of the second polarization grating is 7.5 degrees, after cascading, the diffraction angle of the output light is 10 degrees.

[0050] Taking the first optical path sorting unit 4 as an example, the second quarter-wave plate 41 can convert the two orthogonal light states emitted from the first ferroelectric optical switch 3 into left-handed and right-handed circularly polarized light. The first liquid crystal polarization grating 42 is controlled by an electric field. By utilizing the diffraction and beam-splitting characteristics of the liquid crystal polarization grating, circularly polarized light of different polarization states is output to different ports, thereby realizing optical path sorting and port switching. The function is realized through liquid crystal polarization optical elements, which has a simple structure and is easy to integrate compactly with other optical systems.

[0051] In this embodiment, the number of output ports of the optical switching system increases exponentially with the cascading of more ferroelectric liquid crystal optical switches, quarter-wave plates, and liquid crystal polarization gratings. That is, the number of receiving ports equals 2 to the power of n, where n is the number of liquid crystal polarization gratings. The number of ferroelectric optical switches and quarter-wave plates increases with the number of liquid crystal polarization gratings. As shown in Figure 1, which has four output ports, two liquid crystal polarization gratings are required.

[0052] In some embodiments, as shown in FIG7, the optical switching system further includes: a third ferroelectric optical switch 9, a fourth ferroelectric optical switch 10, a third optical path sorting unit 11, a fourth optical path sorting unit 12, a fourth quarter-wave plate 13, and a fifth quarter-wave plate 14; the fourth quarter-wave plate 13 is located between the second optical path sorting unit 7 and the third ferroelectric optical switch 9; the third optical path sorting switch is located between the third ferroelectric optical switch and the fifth quarter-wave plate 14; and the fourth ferroelectric optical switch 10 is located between the fifth quarter-wave plate 14 and the fourth optical path sorting unit 12.

[0053] In this embodiment, by adding two sets of ferroelectric optical switches and liquid crystal polarization gratings to the system shown in Figure 1, the following can be achieved: Output port arrangement. In this process, the output of the front-end system (i.e., the combination of the previous stage ferroelectric optical switch and the liquid crystal polarizing grating) serves as the input of the subsequent system. By changing the arrangement direction of the grating fringes, the output ports are effectively expanded in a two-dimensional plane. Based on the above expansion idea, by continuously increasing the number of cascaded ferroelectric optical switches and liquid crystal polarizing gratings, the number of output ports can be continuously expanded to meet the port quantity requirements of optical communication applications.

[0054] In some embodiments, as shown in FIG8, the first ferroelectric optical switch 3 includes: a conductive layer 31, an alignment layer 32, a liquid crystal molecule layer 33, and an encapsulation layer 34; the conductive layer 31 is located at the bottom and top of the first ferroelectric optical switch 3; the alignment layer 32 is located on one side of the top conductive layer 31 and on one side of the bottom conductive layer 31; the liquid crystal molecule layer 33 is located between the two alignment layers 32; the encapsulation layer 34 is located between the two conductive layers 31 and abuts against the alignment layer 32 and the liquid crystal molecule layer 33.

[0055] Furthermore, the conductive layer 31 includes a glass substrate 311 and a conductive thin film 312; the conductive thin film 312 is disposed on the side of the glass substrate 311 near the alignment layer 32.

[0056] In this embodiment, the first ferroelectric optical switch 3 and the second ferroelectric optical switch 6 have the same structure and are prepared using the same method. Taking the first ferroelectric optical switch 3 as an example, the first ferroelectric optical switch 3 is composed of two conductive layers 31, two alignment layers 32, a liquid crystal molecule layer 33, and two encapsulation layers 34. The two conductive layers 31 are composed of a glass substrate 311 and a conductive film 312, and the conductive film 312 is composed of a silicon dioxide ion-barrier layer and an ITO transparent conductive layer. The two conductive layers 31 are located at the top and bottom of the first ferroelectric optical switch 3. The alignment layer 32 is composed of azo dye molecules SD1, and the two alignment layers 32 are connected to one side of one of the conductive layers 31. Traditional liquid crystal devices often use materials such as polyimide (PI) as alignment layers. The alignment effect usually depends heavily on high-temperature curing and mechanical friction alignment, resulting in generally uniform global alignment, weak patterning ability, and susceptibility to scratches and large thickness deviations due to friction. Using the azo dye SD1 as the alignment layer results in a thin and uniform film, which not only improves the sensitivity and stability of alignment but also reduces the impact of surface defects on the alignment of liquid crystal molecules, thus leading to a shorter device response time. The liquid crystal molecule layer 33 is composed of ferroelectric liquid crystal and E7 liquid crystal material and is located between the two alignment layers 32. The encapsulation layer 34, composed of polystyrene microspheres and sealant, is used to encapsulate the liquid crystal molecule layer 33.

[0057] The following describes the fabrication method of the ferroelectric optical switch, which includes the following steps: Glass Cleaning: The glass used for the liquid crystal cell fabrication is a 0.7mm thick ITO conductive glass substrate, one side of which is a thin film composed of a silicon dioxide ion barrier layer and an ITO transparent conductive layer. To effectively remove contaminants from the surface of the glass substrate, the cleaning process requires a combination of physical and chemical methods. This process first uses an ultrasonic cleaner to perform ultrasonic cleaning for 30 minutes in a 50°C water bath with added organic detergent, using high-frequency oscillation to remove large particulate contaminants from the glass substrate. After removing the glass from the ultrasonic cleaner, the substrate surface is cleaned with a pure water spray gun to remove any remaining detergent. After blowing off any remaining water droplets on the glass surface with a nitrogen gun, it is immersed in 50°C ultrapure water and ultrasonically cleaned for 30 minutes. After removing the glass from the ultrapure water, any remaining water droplets on the glass surface are blown off again with a nitrogen gun, and the surface liquid is dried in a 200°C oven for 30 minutes to prevent airborne particles from contaminating the glass substrate surface, until the oven emits a beeping warning; Glass Cutting and Ultraviolet (UV) Cleaning: The glass is cut in a cutting machine... Cutting operation of different sizes. After cutting, clean the glass surface with a nitrogen gun to remove any remaining glass fragments. Place the cut glass in a clean glass petri dish with the conductive side facing up, without touching the petri dish, and clean it in a UV cleaner for 10 minutes to improve the substrate's adsorption capacity for the alignment agent; spin-coating alignment layer 32: Sodium azobenzenesulfonate SD1 with a mass ratio of 1% is used as the alignment liquid crystal material for the liquid crystal cell. After connecting the negative pressure air pump to the air hole of the fixing stage, the conductive layer 31 to be spin-coated can be adsorbed at the air hole. The adsorption platform is designed with concentric circular grooves connecting the air holes, which can make the adsorption force on the conductive layer 31 more uniform and effectively prevent slippage. Apply the prepared SD1 solvent evenly to the conductive layer 31 with a dropper and spin-coat at a pre-speed of 500 r / min (5s) and a high speed of 3000 r / min (30s). Place the spin-coated glass substrate on a heating stage (90℃) and anneal for 10 min to evaporate excess solvent and form a stable alignment film on the substrate. The liquid crystal cell was fabricated using two spin-coated conductive layers 31 of SD1. For dispensing and curing: a mixture of 5-micron polystyrene microspheres and UV sealant was used as a spacer, uniformly mixed, and then applied to one conductive layer 31, leaving two notches on one pair of sides. The uncoated conductive layer 31 was offset and placed upside down on the conductive layer 31 with the spacer applied, then placed in a plastic bag and vacuum-sealed to ensure uniform cell thickness. After vacuuming, the area requiring exposure and alignment was covered with light-shielding black tape, and irradiated with a UV lamp for 1 minute to cure the adhesive, forming the liquid crystal cell. The thickness of the ferroelectric-optic switch was measured to be approximately 4.8 microns using a reflectometer connected to a spectrometer. For photoalignment: the liquid crystal cell was placed in a digital mask lithography machine based on a digitally controlled micromirror array (DMD), and the desired pattern was exposed using a 2x objective lens to complete the alignment of the alignment layer 32. Figure 9 shows the exposure image of alignment layer 32 with phase-order design of the polarization grating; Liquid crystal filling and liquid crystal cell sealing: A suitable amount of ferroelectric liquid crystal and E7 liquid crystal are poured into an uncoated notch of the ferroelectric optical switch until the liquid crystal covers the effective alignment area. After filling, the heating stage is turned off and the switch is allowed to cool naturally to room temperature. AB glue is mixed 1:1 and applied to the notch ends on both sides of the glass to seal the ferroelectric optical switch.

[0058] In the above-mentioned method for fabricating ferroelectric optical switches, by using an azo dye alignment layer and an optimized spin-coating process, liquid crystal molecules can be aligned more quickly and uniformly, reducing the device's response time and improving the light modulation effect.

[0059] Existing technologies mostly use traditional ultraviolet exposure methods for liquid crystal alignment, while this device employs digital mask lithography based on a numerically controlled micromirror array, providing higher exposure accuracy and flexible pattern design. This allows the device to be directly used in functional applications such as polarization control and beam deflection. It eliminates the need for physical masks, enabling flexible design changes. Real-time programmability ensures rapid exposure pattern generation. Pixel control precision reaches the micrometer level, making it suitable for fabricating micro / nano optical devices and achieving "what you see is what you get" alignment control.

[0060] Therefore, digital mask lithography technology enables liquid crystal devices to adapt to more complex designs and pattern requirements, providing greater design freedom. Ferroelectric liquid crystals, with their high-speed response and bistable characteristics, reduce power consumption and are suitable for high-speed optical communication scenarios: Ferroelectric liquid crystals have a response speed of 1-100μs, which is 10-1000 times faster than traditional nematic liquid crystals (millisecond level), avoiding inter-symbol interference in signal transmission and ensuring communication quality at high bit rates.

[0061] Ferroelectric liquid crystals (FLCs) exhibit bistable states, requiring only brief electric field pulses (microseconds) to switch molecular orientation states, enabling low-power operation. The ordered molecular arrangement and excellent optical uniformity of FLCs result in insertion losses of only 0.5-2 dB (far lower than the 3-5 dB of semiconductor modulators) when used as optical modulation materials, reducing signal attenuation, extending transmission distance, and decreasing reliance on optical amplifiers. FLC state switching relies on molecular polarization reversals rather than mechanical structural movement (such as the mechanical shutter of traditional optical switches), avoiding mechanical wear and extending lifespan. The layered structure of FLCs makes them less sensitive to temperature changes (-40-85℃) and vibrations than traditional liquid crystals, meeting the environmental adaptability requirements of industrial-grade optical communication equipment. Molecular polarization reversals have no irreversible losses, and performance does not significantly degrade after repeated switching (≥10¹² times), making them suitable for high-frequency state switching scenarios (such as optical switching nodes and dynamic wavelength allocation), and exhibiting good fatigue resistance.

[0062] Therefore, ferroelectric liquid crystals exhibit advantages such as extremely fast response speed and adaptability to high bit rate requirements in high-speed optical communication and other scenarios. Their bistable characteristics enable ultra-low power consumption. They possess excellent optical performance and low signal transmission loss. They are free from mechanical wear, resulting in a long service life. They have strong environmental adaptability, meeting industrial-grade standards. They also exhibit excellent fatigue resistance, making them suitable for high-speed switching scenarios.

[0063] In some embodiments, when the first liquid crystal polarizing grating 42 or the second liquid crystal polarizing grating 72 is rotated by 90°, the one-dimensionally arranged output ports can be adjusted to a two-dimensionally distributed output port.

[0064] In this embodiment, some of the liquid crystal polarization gratings in the system are rotated by 90 degrees, changing the arrangement direction of each diffraction order and resulting in output ports distributed along the y-axis. This distribution change expands the originally one-dimensional arrangement of output ports into a two-dimensional distribution, making it possible to achieve more complex optical signal transmission and processing. Taking a 1×4 system as an example, as shown in Figure 10, the system with the device order unchanged and the second grating rotated by 90 degrees achieves a two-dimensional distribution of output ports. The arrangement.

[0065] In some embodiments, as shown in FIG11, a plurality of collimated input fibers are provided to form a collimated input fiber array; the optical switching system further includes a spliced ​​polarization grating obtained by splicing gratings with gratings of different periods in a region, the number of gratings of the spliced ​​polarization grating corresponding to the number of collimated fibers in the collimated input fiber array.

[0066] In this embodiment, both the input and output ends of the system are fiber microlens collimating arrays, which allows for expansion of the number of input and output ports. Furthermore, the last polarization grating of the system is spliced ​​with gratings of different periods to match the number of output ports, for example, realizing a 4×4 optical switching system as shown in Figure 11.

[0067] In some embodiments, as shown in FIG12, the present invention also provides an optical switching method based on the optical switching system described above, which includes the following steps: S100, controlling the polarity switching of the driving signals of the first ferroelectric optical switch and the second ferroelectric switch through the driving circuit to change the relative direction of the liquid crystal optical axis and convert the incident linearly polarized light into two orthogonally linearly polarized light states; as described in an embodiment of an optical switching system, it will not be repeated here.

[0068] S200: By controlling the first and second optical path sorting units with an electric field, circularly polarized light with different polarization states is output to different ports to achieve optical path sorting and port switching. This is specifically described in an embodiment of an optical switching system and will not be repeated here.

[0069] In summary, the optical switching system and method provided by this invention have the following beneficial effects: Non-mechanical dynamic switching: Utilizing the two stable states of ferroelectric liquid crystals, dynamic switching can be achieved without mechanical assistance. Compared with traditional mechanical optical switches, it has a faster response speed and higher reliability, meeting the high-speed and stable switching requirements of optical communication systems; High-speed and stable output: The high-speed electro-optic modulation characteristics of ferroelectric liquid crystals enable the optical switching system to achieve high-speed port switching while ensuring stable output of the port polarization state. This is crucial for the accurate transmission and processing of signals in high-speed optical communication networks; High diffraction efficiency and extinction ratio: Through the phase-order design of the diffraction grating, a diffraction efficiency of up to 99% is achieved, thereby obtaining a high extinction ratio port output. This helps reduce crosstalk between optical signals and improves the performance and signal quality of the optical switching system; Port scalability: The optical path design of the system has good port scalability, allowing for flexible increases or decreases in the number of ports according to actual needs, adapting to optical communication network applications of different scales.

[0070] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An optical switching system, characterized in that, include: The system comprises a collimated input fiber, a polarizer, a first ferroelectric optical switch, a first optical path sorting unit, a first quarter-wave plate, a second ferroelectric optical switch, a second optical path sorting unit, and a collimated input fiber receiving array; wherein, the collimated input fiber is located on the incident optical path of the polarizer and is used to connect to a laser source; the polarizer is located on the incident optical path of the first ferroelectric optical switch and is used to adjust the incoming incident light into linearly polarized light and input it to the first ferroelectric optical switch; the first ferroelectric switch is used to convert the linearly polarized light into two orthogonally linearly polarized states; the first optical path sorting unit is located on the incident side of the first quarter-wave plate and is used to... Two orthogonally linearly polarized light states are converted into left-handed and right-handed circularly polarized light and input to the first quarter-wave plate; the first quarter-wave plate is located on the incident light path of the second ferroelectric optical switch and is used to convert the left-handed and right-handed circularly polarized light into linearly polarized light and input it to the second ferroelectric optical switch; the second ferroelectric optical switch is used to convert the linearly polarized light into two orthogonally linearly polarized light states; the second optical path sorting unit is located on the incident light path of the collimated input fiber receiving array and is used to convert the linearly polarized light into left-handed and right-handed circularly polarized light; the collimated input fiber receiving array is used to receive each path of circularly polarized light.

2. The optical switching system according to claim 1, characterized in that, The first optical path sorting unit includes: a second quarter-wave plate and a first liquid crystal polarization grating; the second quarter-wave plate is located between the first ferroelectric optical switch and the first liquid crystal polarization grating, and is used to convert the two orthogonally linearly polarized light output by the first ferroelectric optical switch into left-handed circularly polarized light and right-handed circularly polarized light; the first liquid crystal polarization grating is used to output the left-handed circularly polarized light and right-handed circularly polarized light to the first quarter-wave plate.

3. The optical switching system according to claim 2, characterized in that, The second optical path sorting unit includes: a third quarter-wave plate and a second liquid crystal polarization grating; the third quarter-wave plate is located between the second ferroelectric optical switch and the second liquid crystal polarization grating, and is used to convert the orthogonally linearly polarized light output by the second ferroelectric optical switch into left-hand circularly polarized light and right-hand circularly polarized light; the second liquid crystal polarization grating is used to output the left-hand circularly polarized light and right-hand circularly polarized light to the collimated input fiber receiving array.

4. The optical switching system according to claim 3, characterized in that, The first ferroelectric optical switch and the second ferroelectric optical switch are controlled by a driving signal. By controlling the polarity switching of the driving signal, the incident linearly polarized light is converted into two orthogonally linearly polarized light states.

5. The optical switching system according to claim 3, characterized in that, When the first liquid crystal polarizing grating or the second liquid crystal polarizing grating is rotated by 90°, the one-dimensionally arranged output ports can be adjusted to a two-dimensionally distributed output port.

6. The optical switching system according to claim 1, characterized in that, The first ferroelectric optical switch includes: a conductive layer, an alignment layer, a liquid crystal molecule layer, and an encapsulation layer; the conductive layers are located at the bottom and top of the first ferroelectric optical switch respectively; the alignment layers are located on one side of the top conductive layer and on one side of the bottom conductive layer respectively; the liquid crystal molecule layer is located between the two alignment layers; the encapsulation layer is located between the two conductive layers and abuts against the alignment layer and the liquid crystal molecule layer.

7. The optical switching system according to claim 6, characterized in that, The conductive layer includes a glass substrate and a conductive thin film; the conductive thin film is disposed on the side of the glass substrate near the alignment layer.

8. The optical switching system according to claim 1, characterized in that, Also includes: The third ferroelectric optical switch, the fourth ferroelectric optical switch, the third optical path sorting unit, the fourth optical path sorting unit, the fourth quarter-wave plate and the fifth quarter-wave plate; The fourth quarter-wave plate is located between the second optical path sorting unit and the third ferroelectric optical switch; The third optical path sorting switch is located between the third ferroelectric optical switch and the fifth quarter-wave plate; the fourth ferroelectric optical switch is located between the fifth quarter-wave plate and the fourth optical path sorting unit.

9. The optical switching system according to claim 1, characterized in that, The collimated input fiber is provided in several parts and forms a collimated input fiber array; the optical switching system also includes a spliced ​​polarization grating obtained by splicing gratings of different periods in regions, and the number of gratings of the spliced ​​polarization grating corresponds to the number of collimated fibers in the collimated input fiber array.

10. An optical switching method based on the optical switching system according to any one of claims 1-9, characterized in that, The steps include: controlling the polarity switching of the driving signals of the first ferroelectric optical switch and the second ferroelectric switch through the driving circuit to change the relative direction of the liquid crystal optical axis and convert the incident linearly polarized light into two orthogonally linearly polarized light states. By controlling the first and second optical path sorting units with an electric field, circularly polarized light with different polarization states is output to different ports to achieve optical path sorting and port switching.

Images