Method, apparatus and system for light field vector mode conversion

Abstract

The application provides a method, device and system for light field vector mode conversion, the method comprising: acquiring a cylindrical vector beam field, a fundamental mode Gaussian light array field and a first geometric phase multi-plane light transformation field; determining a first light field and a second light field based on the cylindrical vector beam field, the fundamental mode Gaussian light array field and the first geometric phase multi-plane light transformation field; acquiring a second geometric phase corresponding to a preset condition based on a difference between orthogonal basis vectors of the first geometric phase, the first light field and the second light field and the preset condition; determining a second geometric phase multi-plane light transformation field by using a vector wavefront matching mode based on the second geometric phase; and converting the fundamental mode Gaussian light array field and the cylindrical vector beam field based on the second geometric phase multi-plane light transformation field, thereby realizing multiplexing and demultiplexing of the cylindrical vector beam field, greatly improving the channel capacity of the optical fiber and improving the transmission efficiency of the optical fiber communication.

Description

[0001] This application claims priority to Chinese patent application No. CN2023101571502, filed on February 17, 2023. Technical Field

[0002] This application belongs to the field of data optical transmission technology, and in particular relates to a method, apparatus and system for optical field vector mode conversion. Background Technology

[0003] Cylindrical vector beams, as intrinsic modes of optical fibers, exhibit stable transmission characteristics in optical fibers, making them well-suited for transmission in optical fibers. They can significantly increase the channel capacity of optical fibers without expanding the system bandwidth.

[0004] Currently, anisotropic multiplane optical transform fields can demultiplex cylindrical vector beams, allowing cylindrical vector beams of different orders to converge into long strip-shaped light spots at different locations. These long strip-shaped light spots are then coupled into optical fibers to achieve information transmission. However, the aforementioned method of demultiplexing cylindrical vector beams using anisotropic multiplane optical transform fields can only perform phase modulation on the left-hand circularly polarized component and the right-hand circularly polarized component of the cylindrical vector beam, respectively.

[0005] Existing multi-plane optical transformation fields have the problem that they can only perform phase modulation on the left-hand circularly polarized component and the right-hand circularly polarized component of a cylindrical vector beam, respectively. Summary of the Invention

[0006] This application provides a method, apparatus, system, electronic device, and storage medium for optical field vector mode conversion, which can solve the problem that multi-plane optical transformation fields can only perform phase modulation on the left-hand circularly polarized component and the right-hand circularly polarized component of a cylindrical vector beam, respectively.

[0007] In a first aspect, embodiments of this application provide a method for optical field vector mode conversion, including:

[0008] Obtain the cylindrical vector beam field, the fundamental mode Gaussian light array field, and the first geometric phase multiplane light transformation field, wherein any plane in the first geometric phase multiplane light transformation field includes one or more first geometric phases;

[0009] Based on the cylindrical vector beam field and the first geometric phase multiplane light transformation field, determine the first light field corresponding to any plane of the first geometric phase multiplane light transformation field through which the cylindrical vector beam field sequentially passes;

[0010] Based on the fundamental mode Gaussian optical array field and the first geometric phase multiplane optical transformation field, determine the second optical field corresponding to any plane of the first geometric phase multiplane optical transformation field through which the Gaussian optical array field passes in reverse order;

[0011] Based on the orthogonal basis difference values ​​of the first geometric phase, the first light field, and the second light field, and a preset condition, the second geometric phase corresponding to the preset condition is obtained;

[0012] Based on the second geometric phase, the multi-plane optical transformation field of the second geometric phase is determined by vector wavefront matching.

[0013] Based on the second geometric phase multiplane light transformation field, the fundamental mode Gaussian light array field and the cylindrical vector beam field are mutually converted.

[0014] In one embodiment, obtaining the second geometric phase corresponding to the preset conditions based on the orthogonal basis difference values ​​of the first geometric phase, the first optical field, and the second optical field, and the preset conditions, includes:

[0015] Based on the first geometric phase, the first light field, and the second light field of any plane, the orthogonal basis difference value of the first light field and the second light field is iteratively calculated until the orthogonal basis difference value satisfies the preset condition;

[0016] The summation of the orthogonal basis differences is determined by performing a summation operation on the orthogonal basis differences values ​​of each plane of the first geometric phase multiplane optical transformation field that satisfy the preset conditions.

[0017] Based on the sum of the orthogonal basis vector differences, determine the second geometric phase corresponding to the sum of the orthogonal basis vector differences.

[0018] In one embodiment, the preset condition is that the orthogonal basis difference value is the minimum value of the orthogonal basis difference value between the first light field and the second light field corresponding to each of the planes.

[0019] In one embodiment, the formula for calculating the difference of the orthogonal basis vectors is:

[0020]

[0021] Wherein, Δ is the difference value of the orthogonal basis vectors;

[0022] e is a constant, the base of the natural logarithm function;

[0023] j represents phase modulation;

[0024] i is the index of any plane in the first geometric phase multiplane optical transformation field;

[0025] Ci is the first light field corresponding to the plane with index i;

[0026] Gi is the second light field corresponding to the plane with index i;

[0027] LCP stands for left-handed polarized light;

[0028] RCP stands for right-handed polarized light;

[0029] θ1 is the first geometric phase.

[0030] In one embodiment, determining the multi-plane optical transformation field of the second geometric phase based on the second geometric phase using vector wavefront matching includes:

[0031] Based on the second geometric phase, the vector wavefront matching is sequentially iterated using the argument calculation formula to obtain the third optical field corresponding to any plane of the first optical field propagating to the first geometric phase multiplane optical transformation field.

[0032] Based on the second geometric phase, the reverse iteration of vector wavefront matching is performed using the argument calculation formula to obtain the fourth optical field corresponding to any plane of the multi-plane optical transformation field of the first geometric phase propagating from the second optical field.

[0033] The second geometric phase multiplane optical transformation field is determined based on the third and fourth optical fields corresponding to each of the planes.

[0034] In one embodiment, the argument calculation formula is:

[0035]

[0036] Wherein, θ2 is the second geometric phase;

[0037] Reg is the argument operator;

[0038] i is the index of any plane in the first geometric phase multiplane optical transformation field;

[0039] i * It is the index of any plane in the second geometric phase multiplane optical transformation field;

[0040] Ci is the first light field corresponding to the plane with index i;

[0041] Gi is the second light field corresponding to the plane with index i;

[0042] Ci * For the sequence number i * The third light field corresponding to the plane;

[0043] Gi* For the sequence number i * The fourth light field corresponding to the plane;

[0044] m is the number of planes in the second geometric phase multiplane optical transformation field;

[0045] LCP stands for left-handed polarized light;

[0046] RCP stands for right-handed polarized light.

[0047] Secondly, embodiments of this application provide an apparatus for optical field vector mode conversion, comprising:

[0048] The first acquisition module is used to acquire the cylindrical vector beam field, the fundamental mode Gaussian light array field, and the first geometric phase multiplane light transformation field, wherein any plane in the first geometric phase multiplane light transformation field includes one or more first geometric phases;

[0049] The first determining module is used to determine, based on the cylindrical vector beam field and the first geometric phase multiplane light transformation field, the first light field corresponding to any plane of the first geometric phase multiplane light transformation field through which the cylindrical vector beam field sequentially passes;

[0050] The second determining module is used to determine, based on the fundamental mode Gaussian optical array field and the first geometric phase multiplane optical transformation field, the second optical field corresponding to any plane of the first geometric phase multiplane optical transformation field after the Gaussian optical array field passes in reverse order.

[0051] The second acquisition module is used to acquire the second geometric phase corresponding to the preset conditions based on the first geometric phase, the orthogonal basis difference value of the first light field and the second light field and the preset conditions;

[0052] The third determining module is used to determine the multi-plane optical transformation field of the second geometric phase based on the second geometric phase using a vector wavefront matching method;

[0053] The conversion module is used to convert the fundamental mode Gaussian light array field and the cylindrical vector beam field to each other based on the second geometric phase multiplane light transformation field.

[0054] Thirdly, embodiments of this application provide a communication system for optical field vector mode conversion, including a first input / output module, a vector wavefront matching module, a reflector, and a second input / output module;

[0055] Wherein, the first input / output module is used to receive or output a fundamental mode Gaussian light array field, the second input / output module is used to receive or output a cylindrical vector beam field, the vector wavefront matching module is used to execute the method described in any one of the first aspects, and the reflector is used to realize the mutual conversion between the fundamental mode Gaussian light array field and the cylindrical vector beam field.

[0056] It is understood that the beneficial effects of the second and third aspects mentioned above can be found in the relevant descriptions in the first aspect above, and will not be repeated here.

[0057] The beneficial effects of the embodiments in this application compared with the prior art are:

[0058] By acquiring the cylindrical vector beam field, the fundamental mode Gaussian optical array field, and the first geometric phase multi-plane optical transformation field, wherein each plane in the first geometric phase multi-plane optical transformation field includes one or more first geometric phases; based on the cylindrical vector beam field and the first geometric phase multi-plane optical transformation field, the first optical field corresponding to the cylindrical vector beam field sequentially passing through any plane of the first geometric phase multi-plane optical transformation field is determined; based on the fundamental mode Gaussian optical array field and the first geometric phase multi-plane optical transformation field, the second optical field corresponding to the Gaussian optical array field reversely passing through any plane of the first geometric phase multi-plane optical transformation field is determined; based on the orthogonal basis difference values ​​of the first geometric phase, the first optical field, and the second optical field, and preset conditions, the second geometric phase corresponding to the preset conditions is obtained; based on the second geometric phase... The phase is determined by a vector wavefront matching method to establish the second geometric phase multiplane optical transformation field. Based on this field, the fundamental mode Gaussian optical array field and the cylindrical vector beam field are mutually converted. Since the second geometric phase under preset conditions is obtained and the vector wavefront matching method is used to determine the second geometric phase multiplane optical transformation field, when the cylindrical vector beam field passes through it, the left-hand and right-hand polarization components of the cylindrical vector beam field can be simultaneously modulated by the second geometric phase. This achieves multiplexing and demultiplexing of the cylindrical vector beam field, i.e., mutual conversion between the fundamental mode Gaussian optical array field and the cylindrical vector beam field, thereby significantly improving the channel capacity of the optical fiber and increasing the transmission efficiency of optical fiber communication. Attached Figure Description

[0059] To more clearly illustrate the technical solutions in the embodiments of this application, 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0060] Figure 1This is a schematic flowchart of a method for converting light field vector modes according to an embodiment of this application;

[0061] Figure 2 This is a flowchart illustrating the process of obtaining the second geometric phase corresponding to the preset conditions based on the orthogonal basis difference values ​​of the first geometric phase, the first light field, and the second light field, and the preset conditions, according to another embodiment of this application.

[0062] Figure 3 This is a schematic diagram of the process for determining the multi-plane optical transformation field of the second geometric phase based on the second geometric phase using vector wavefront matching, according to another embodiment of this application.

[0063] Figure 4 This is a schematic diagram of the structure of a device for optical field vector mode conversion provided in an embodiment of this application;

[0064] Figure 5 This is a schematic diagram of the structure of a system for optical field vector mode conversion provided in an embodiment of this application;

[0065] Figure 6 This is a schematic diagram illustrating the conversion between a cylindrical vector beam and a fundamental Gaussian optical array field in a system for optical field vector mode conversion provided in this application embodiment.

[0066] Figure 7 This is a schematic diagram illustrating the effect of light field vector mode conversion provided in an embodiment of this application. Detailed Implementation

[0067] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0068] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0069] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0070] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0071] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0072] The meanings of some terms in this application are as follows:

[0073] Geometric phase: In this application, the geometric phase is a geometric phase related to the evolution of optical polarization, and the geometric phase is the Pancharatnam-Berry Phase (PB geometric phase).

[0074] Cylindrical Vector Beam (CVB): A vector beam in which the polarization state at the cross section is circularly symmetrically distributed and the center is a polarization singularity.

[0075] Fundamental mode Gaussian light array field: A horizontally aligned fundamental mode linearly polarized Gaussian light array.

[0076] Multi-planar Light Conversion (MPLC): An optical conversion field consisting of multiple planar phase masks, where light rays are converted after passing through all the planes in sequence.

[0077] Right-circular polarizer (RCP) and left-circular polarizer (LCP): When viewed against the direction of the light, light whose electric vector rotates clockwise is called right-circular polarizer, and light whose electric vector rotates counterclockwise is called left-circular polarizer.

[0078] With the ever-expanding demands for information transmission, single-mode fiber is limited by the Shannon limit; theoretically, a single fiber can only transmit a maximum channel capacity of 100 Tbit / s, which is insufficient to meet the capacity requirements of the big data era. Cylindrical vector beams, as the eigenmodes of optical fibers, exhibit stable transmission characteristics within fibers, making them well-suited for fiber transmission. They can significantly increase the channel capacity of optical fibers without expanding the system bandwidth.

[0079] Space-division multiplexing (SDM) allows the same optical signal to be reused in different spaces, effectively increasing the capacity of fiber optic channels. SDM can also be achieved using spatially orthogonal modes. These spatially orthogonal modes are not only mutually orthogonal but also compatible with traditional multiplexing methods (such as time-division multiplexing, polarization multiplexing, and wavelength-division multiplexing). These mutually orthogonal modes can be represented by various modes, such as orbital angular momentum (OAM) and cylindrical vector beam (CVB).

[0080] When cylindrical vector beams are used to transmit information via multiplexing, cylindrical vector beams of different orders are used in different channels to transmit information. These channels overlap spatially, so when receiving information from a cylindrical vector beam at the receiving end, the information needs to be demodulated from the different channels.

[0081] Currently, anisotropic multiplane optical transform fields can demultiplex cylindrical vector beams, allowing cylindrical vector beams of different orders to converge into long strip-shaped light spots at different locations. These long strip-shaped light spots are then coupled into optical fibers to achieve information transmission. However, the aforementioned method of demultiplexing cylindrical vector beams using anisotropic multiplane optical transform fields can only perform phase modulation on the left-hand circularly polarized component and the right-hand circularly polarized component of the cylindrical vector beam, respectively.

[0082] Existing multi-plane optical transformation fields have the problem that they can only perform phase modulation on the left-hand circularly polarized component and the right-hand circularly polarized component of a cylindrical vector beam, respectively.

[0083] This application embodiment obtains a cylindrical vector beam field, a fundamental mode Gaussian optical array field, and a first geometric phase multi-plane optical transformation field, wherein any plane in the first geometric phase multi-plane optical transformation field includes one or more first geometric phases; based on the cylindrical vector beam field and the first geometric phase multi-plane optical transformation field, it determines the first optical field corresponding to the cylindrical vector beam field sequentially passing through any plane of the first geometric phase multi-plane optical transformation field; based on the fundamental mode Gaussian optical array field and the first geometric phase multi-plane optical transformation field, it determines the second optical field corresponding to the Gaussian optical array field reversely passing through any plane of the first geometric phase multi-plane optical transformation field; based on the orthogonal basis difference values ​​of the first geometric phase, the first optical field, and the second optical field, and a preset condition, it obtains the second geometric phase corresponding to the preset condition; based on the first geometric phase, the orthogonal basis difference value of the first optical field and the second optical field, and a preset condition, it obtains the second geometric phase corresponding to the preset condition; based on the first... The second geometric phase is determined using a vector wavefront matching method to establish a multi-plane optical transformation field. Based on this field, the fundamental mode Gaussian optical array field and the cylindrical vector beam field are mutually converted. Since the second geometric phase is obtained under preset conditions and determined using vector wavefront matching, the left-hand and right-hand polarization components of the cylindrical vector beam field can be simultaneously modulated by the second geometric phase when passing through it. This achieves multiplexing and demultiplexing of the cylindrical vector beam field, thus realizing the mutual conversion between the fundamental mode Gaussian optical array field and the cylindrical vector beam field. This significantly improves the channel capacity of the optical fiber and enhances the transmission efficiency of optical fiber communication.

[0084] The technical solution of this application will be described below through specific embodiments.

[0085] Firstly, such as Figure 1 As shown, this application provides a method for optical field vector mode conversion, including:

[0086] S100, acquire the cylindrical vector beam field, the fundamental mode Gaussian light array field, and the first geometric phase multiplane light transformation field.

[0087] In one embodiment, a coaxial cylindrical vector beam field, a fundamental mode Gaussian light array field, and a first geometric phase multiplane light transformation field are obtained. The cylindrical vector beam field and the fundamental mode Gaussian light array field serve as two light fields for light field vector mode conversion, respectively. The first geometric phase multiplane light transformation field is the initial intermediate light field for the two light field vector mode conversions. The first geometric phase multiplane light transformation field includes multiple planes; for example, the number of planes in the first geometric phase multiplane light transformation field can be any number from 1 to 5. Each plane in the first geometric phase multiplane light transformation field includes one or more first geometric phases. The number of planes in the first geometric phase multiplane light transformation field is not limited; the specific number of planes can be set as needed.

[0088] In one embodiment, the number of planes in the first geometric phase multiplane optical transformation field is 5, and the plane numbers of the first geometric phase multiplane optical transformation field are sequentially from 1 to 5, and in reverse order from 5 to 1.

[0089] The Jones vector of an l-th order cylindrical vector beam can be expressed as:

[0090]

[0091] in, It is the azimuth angle. denoted as the initial azimuth angle, e as the base of the natural logarithm function, LCP as left-handed polarized light, RCP as right-handed polarized light, OAM as the orbital angular momentum of the cylindrical vector beam, and j as the phase modulation.

[0092] The above equation shows that an nth-order cylindrical vector beam can be regarded as a superposition of right-handed and left-handed polarized light with opposite orbital angular momentum.

[0093] S200, based on the cylindrical vector beam field and the first geometric phase multi-plane light transformation field, determines the first light field corresponding to any plane of the first geometric phase multi-plane light transformation field through which the cylindrical vector beam field sequentially passes.

[0094] In one embodiment, based on the cylindrical vector beam field and the first geometric phase multiplane light transformation field, a first light field corresponding to any plane of the first geometric phase multiplane light transformation field through which the cylindrical vector beam field sequentially passes is determined. For example, in a first geometric phase multiplane light transformation field with 5 planes, each plane corresponds to a first light field, which is the light field formed by the cylindrical vector beam field sequentially passing through any plane of the first geometric phase multiplane light transformation field.

[0095] S300, based on the fundamental mode Gaussian optical array field and the first geometric phase multi-plane optical transformation field, determines the second optical field corresponding to any plane of the first geometric phase multi-plane optical transformation field in reverse order through the Gaussian optical array field.

[0096] In one embodiment, based on the fundamental mode Gaussian optical array field and the first geometric phase multiplane optical transformation field, a second optical field corresponding to any plane of the first geometric phase multiplane optical transformation field passing in reverse order through the Gaussian optical array field is determined. For example, if the first geometric phase multiplane optical transformation field has 5 planes, then each plane corresponds to a second optical field. The second optical field is the optical field formed by the Gaussian optical array field passing in reverse order through any plane of the first geometric phase multiplane optical transformation field.

[0097] S400: Based on the first geometric phase, the orthogonal basis difference between the first and second light fields, and preset conditions, obtain the second geometric phase corresponding to the preset conditions.

[0098] In one embodiment, based on the first geometric phase, the orthogonal basis difference between the first and second light fields, and the preset conditions, the second geometric phase corresponding to the preset conditions is obtained. This is beneficial for phase modulation of the cylindrical vector beam field based on the second geometric phase that satisfies the preset conditions, and facilitates light field conversion.

[0099] In the prior art, for a multiplane optical transformation field with a first geometric phase, the Jones matrix is:

[0100]

[0101] The phase modulation of left-handed circularly polarized light by the first geometric phase multiplane optical transformation field is as follows:

[0102]

[0103] The phase modulation of right-hand circularly polarized light by the first geometric phase multiplane optical transformation field is as follows:

[0104]

[0105] The first geometric phase multiplane light transformation field modulates the phase of left-handed and right-handed circularly polarized light in opposite ways.

[0106] In one embodiment, if a cylindrical vector beam field sequentially passes through a plane of a first geometrical phase multiplane optical transformation field to form a first optical field, and simultaneously a Gaussian optical array field sequentially passes through the same plane of the first geometrical phase multiplane optical transformation field to form a second optical field, the first optical field is converted into the second optical field. This is achieved by using orthogonal basis vectors derived from the left-hand and right-hand circular polarizations of the cylindrical vector beam field. This process is represented as follows:

[0107]

[0108] Where e is the base of the natural logarithm function; θ1 is the first geometric phase; j is the phase modulation; i is the index of any plane in the first geometric phase multiplane optical transformation field; Ci is the first optical field corresponding to the plane with index i; Gi is the second optical field corresponding to the plane with index i; LCP is left-handed polarized light; RCP is right-handed polarized light.

[0109] In one embodiment, such as Figure 2 As shown, based on the orthogonal basis vector difference between the first geometric phase, the first light field, and the second light field, and a preset condition, the second geometric phase corresponding to the preset condition is obtained, including:

[0110] S410, based on the first geometric phase, the first light field, and the second light field of any plane, iteratively calculates the orthogonal basis difference value of the first light field and the second light field until the orthogonal basis difference value meets the preset condition.

[0111] In one embodiment, based on the first geometric phase, the first light field, and the second light field of any plane, the orthogonal basis difference value of the first light field and the second light field is iteratively calculated until the orthogonal basis difference value meets the preset condition, so as to obtain the second geometric phase of each plane through iterative calculation.

[0112] In one embodiment, the preset condition is that the orthogonal basis difference is the minimum value of the orthogonal basis difference between the first and second light fields corresponding to each plane. That is, for any plane, the orthogonal basis difference between the first and second light fields corresponding to the plane is iteratively calculated using multiple first geometric phases until the orthogonal basis difference between the first and second light fields corresponding to the plane is the minimum value.

[0113] In one embodiment, the orthogonal basis difference is iteratively calculated for each plane of the first geometric phase multiplane optical transformation field until the orthogonal basis difference between the first and second optical fields corresponding to each plane is minimized.

[0114] In one embodiment, the formula for calculating the difference of orthogonal basis vectors is:

[0115]

[0116] Where Δ is the orthogonal basis difference; e is the base of the natural logarithm function; j is the phase modulation; i is the index of any plane in the first geometric phase multiplane optical transformation field; Ci is the first optical field corresponding to the plane with index i; Gi is the second optical field corresponding to the plane with index i; LCP is left-handed polarized light; RCP is right-handed polarized light; θ1 is the first geometric phase.

[0117] S420, perform a summation operation on the orthogonal basis differences of each plane of the first geometric phase multiplane optical transformation field that satisfy the preset conditions, and determine the total sum of the orthogonal basis differences.

[0118] In one embodiment, the orthogonal basis difference values ​​of each plane of the first geometric phase multiplane optical transformation field that satisfy a preset condition are summed to determine the total sum of the orthogonal basis difference values. In this way, the minimum orthogonal basis difference values ​​of each plane of the entire first geometric phase multiplane optical transformation field are summed, and the total sum of the orthogonal basis difference values ​​is the minimum overall difference value of the entire first geometric phase multiplane optical transformation field.

[0119] The sum of the differences of orthogonal basis vectors is expressed as:

[0120]

[0121] Where Δ is the difference of orthogonal basis vectors, where Δ 总 is the sum of the differences between orthogonal basis vectors, and m is the number of planes in the first multiplane optical transformation field.

[0122] S430, based on the sum of the orthogonal basis vector differences, determine the second geometric phase corresponding to the sum of the orthogonal basis vector differences.

[0123] In one embodiment, the second geometric phase corresponding to the sum of the orthogonal basis differences is determined based on the sum of the orthogonal basis differences. That is, the geometric phase that makes the sum of the orthogonal basis differences also the minimum value is selected as the second geometric phase. This is beneficial to improve the optical field conversion efficiency, reduce information loss, and improve the quality of optical communication during optical field conversion.

[0124] S500, based on the second geometric phase, uses vector wavefront matching to determine the multi-plane optical transformation field of the second geometric phase.

[0125] In one embodiment, based on the second geometric phase, the optical field corresponding to each plane in the first geometric phase multiplane optical transformation field is updated by vector wavefront matching to determine the second geometric phase multiplane optical transformation field, which facilitates the improvement of optical field conversion efficiency.

[0126] In one embodiment, such as Figure 3 As shown, based on the second geometric phase, the multi-plane optical transformation field of the second geometric phase is determined using a vector wavefront matching method, including:

[0127] S510, based on the second geometric phase, uses the argument calculation formula to perform sequential iteration of vector wavefront matching to obtain the third optical field corresponding to any plane of the first optical field propagating to the first geometric phase multi-plane optical transformation field.

[0128] In one embodiment, based on the second geometric phase, the vector wavefront matching is sequentially iterated using the argument calculation formula to obtain the third optical field corresponding to any plane of the first geometric phase multi-plane optical transformation field after the first optical field is modulated by the second geometric phase, so as to perform vector wavefront matching on each plane.

[0129] In one embodiment, the argument calculation formula is:

[0130]

[0131] Where θ2 is the second geometric phase; Reg is the argument operator;

[0132] i is the index of any plane in the first geometric phase multiplane optical transformation field;

[0133] i * It represents the index of any plane in the second geometric phase multiplane optical transformation field;

[0134] Ci is the first light field corresponding to the plane with index i;

[0135] Gi is the second light field corresponding to the plane with index i;

[0136] Ci * For the sequence number i * The third light field corresponding to the plane;

[0137] Gi * For the sequence number i * The fourth light field corresponding to the plane;

[0138] m is the number of planes in the second geometric phase multiplane light transformation field;

[0139] LCP stands for left-handed polarized light; RCP stands for right-handed polarized light.

[0140] S520, based on the second geometric phase, uses the argument calculation formula to perform reverse iteration of vector wavefront matching to obtain the fourth optical field corresponding to any plane of the multi-plane optical transformation field of the first geometric phase propagating from the second optical field.

[0141] In one embodiment, based on the second geometric phase, the reverse iteration of vector wavefront matching is performed using the argument calculation formula to obtain the fourth optical field corresponding to any plane of the first geometric phase multiplane optical transformation field after the second optical field is modulated by the second geometric phase, so as to perform vector wavefront matching on each plane.

[0142] S530 determines the second geometric phase multiplane optical transformation field based on the third and fourth optical fields corresponding to each plane.

[0143] In one embodiment, when each plane of the first geometric phase multiplane optical transformation field obtains the corresponding third and fourth optical fields after vector wavefront matching, the first geometric phase multiplane optical transformation field is determined as the second geometric phase multiplane optical transformation field.

[0144] S600 is based on a second geometric phase multi-plane light transformation field, in which the fundamental mode Gaussian light array field and the cylindrical vector beam field are mutually converted.

[0145] In one embodiment, based on the second geometric phase multiplane optical transformation field, the fundamental mode Gaussian optical array field and the cylindrical vector beam field are mutually converted. Since the second geometric phase is obtained and the second geometric phase multiplane optical transformation field is determined by vector wavefront matching, when the cylindrical vector beam field passes through the second geometric phase multiplane optical transformation field, the left-hand and right-hand polarization components of the cylindrical vector beam field can be simultaneously phase-modulated by the second geometric phase. Therefore, the multiplexing and demultiplexing of the cylindrical vector beam field are realized, thereby significantly improving the channel capacity of the optical fiber and improving the transmission efficiency of optical fiber communication.

[0146] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0147] The advantages of this embodiment compared to the prior art are:

[0148] By acquiring the cylindrical vector beam field, the fundamental mode Gaussian optical array field, and the first geometric phase multi-plane optical transformation field, wherein each plane in the first geometric phase multi-plane optical transformation field includes one or more first geometric phases; based on the cylindrical vector beam field and the first geometric phase multi-plane optical transformation field, the first optical field corresponding to the cylindrical vector beam field sequentially passing through any plane of the first geometric phase multi-plane optical transformation field is determined; based on the fundamental mode Gaussian optical array field and the first geometric phase multi-plane optical transformation field, the second optical field corresponding to the Gaussian optical array field reversely passing through any plane of the first geometric phase multi-plane optical transformation field is determined; based on the orthogonal basis difference values ​​of the first geometric phase, the first optical field, and the second optical field, and preset conditions, the second geometric phase corresponding to the preset conditions is obtained; based on the second geometric phase... The phase is determined by a vector wavefront matching method to establish the second geometric phase multiplane optical transformation field. Based on this field, the fundamental mode Gaussian optical array field and the cylindrical vector beam field are mutually converted. Since the second geometric phase under preset conditions is obtained and the vector wavefront matching method is used to determine the second geometric phase multiplane optical transformation field, when the cylindrical vector beam field passes through it, the left-hand and right-hand polarization components of the cylindrical vector beam field can be simultaneously modulated by the second geometric phase. This achieves multiplexing and demultiplexing of the cylindrical vector beam field, i.e., mutual conversion between the fundamental mode Gaussian optical array field and the cylindrical vector beam field, thereby significantly improving the channel capacity of the optical fiber and increasing the transmission efficiency of optical fiber communication.

[0149] Secondly, such as Figure 4 As shown, this embodiment provides a device for optical field vector mode conversion, including:

[0150] The first acquisition module 100 is used to acquire the cylindrical vector beam field, the fundamental mode Gaussian light array field, and the first geometric phase multiplane light transformation field, wherein any plane in the first geometric phase multiplane light transformation field includes one or more first geometric phases;

[0151] The first determining module 200 is used to determine the first light field corresponding to any plane of the first geometric phase multiplane light transformation field through which the cylindrical vector beam field sequentially passes, based on the cylindrical vector beam field and the first geometric phase multiplane light transformation field.

[0152] The second determining module 300 is used to determine the second optical field corresponding to any plane of the first geometric phase multiplane optical transformation field after the Gaussian optical array field passes in reverse order, based on the fundamental mode Gaussian optical array field and the first geometric phase multiplane optical transformation field.

[0153] The second acquisition module 400 is used to acquire the second geometric phase corresponding to the preset conditions based on the first geometric phase, the orthogonal basis difference value of the first light field and the second light field and the preset conditions.

[0154] The third determining module 500 is used to determine the second geometric phase multiplane optical transformation field based on the second geometric phase and using a vector wavefront matching method.

[0155] The conversion module 600 is used to convert between the fundamental mode Gaussian light array field and the cylindrical vector beam field based on the second geometric phase multiplane light transformation field.

[0156] Thirdly, such as Figure 5 As shown, this embodiment provides a communication system for optical field vector mode conversion, including a first input / output module, a vector wavefront matching module, a reflector, and a second input / output module.

[0157] In one embodiment, the first input / output module is used to receive or output a fundamental mode Gaussian light array field, the second input / output module is used to receive or output a cylindrical vector beam field, the vector wavefront matching module is used to perform the method of any one of the first aspects, and the reflector is used to realize the mutual conversion between the fundamental mode Gaussian light array field and the cylindrical vector beam field.

[0158] In one embodiment, such as Figure 6 As shown, after vector wavefront matching, the 11th-order cylindrical vector beam field undergoes multiple reflections between multiple planes of the second geometric phase multiplane optical transformation field and the reflective layer of the reflector, and is then demultiplexed and converted into an 11-column fundamental mode Gaussian optical array field. Similarly, the 11-column fundamental mode Gaussian optical array field undergoes multiple reflections between multiple planes of the second geometric phase multiplane optical transformation field and the reflective layer of the reflector, and is then multiplexed and converted into an 11th-order cylindrical vector beam field. It should be noted that the specific order of the cylindrical vector beam field used in this embodiment is not limited, and can be set according to the specific needs of optical communication. For example, it can also be a cylindrical vector beam field of any order from 1st to 11th, or even cylindrical vector beam fields of orders 3rd, 4th, 5th, 6th, 7th, 8th, 9th, and 10th.

[0159] In one embodiment, such as Figure 7As shown, the PB geometric phase multiplane optical transformation field can realize the mutual conversion between the cylindrical vector beam field of 11 orders and the fundamental mode Gaussian optical array field. From left to right, the first column shows the PB phase distribution on planes 1 to 5, the second column shows the total optical field conversion process from the fundamental mode Gaussian optical array field to the coaxial cylindrical vector beam field, the third column shows the total optical field conversion process from the coaxial cylindrical vector beam field to the fundamental mode Gaussian optical array field during demultiplexing, and the fourth column shows the conversion effect diagram of the light of the cylindrical vector beam field of each order and the Gaussian light spot of the corresponding Gaussian optical array field during multiplexing / demultiplexing.

[0160] It should be noted that the information interaction and execution process between the above-mentioned devices / modules are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0161] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0162] It is understood that the beneficial effects of the second and third aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.

[0163] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments of this application can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms.

[0164] The computer-readable medium may include at least: any entity or device capable of carrying computer program code to a photographic device / terminal device, recording media, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media. Examples include USB flash drives, portable hard drives, magnetic disks, or optical discs. In some jurisdictions, according to legislation and patent practice, computer-readable media may not be electrical carrier signals or telecommunication signals.

[0165] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0166] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0167] In the embodiments provided in this application, it should be understood that the disclosed apparatus / network devices and methods can be implemented in other ways. For example, the apparatus / network device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0168] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0169] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for converting light field vector modes, characterized in that, include: Obtain the cylindrical vector beam field, the fundamental mode Gaussian light array field, and the first geometric phase multiplane light transformation field, wherein any plane in the first geometric phase multiplane light transformation field includes one or more first geometric phases; Based on the cylindrical vector beam field and the first geometric phase multiplane light transformation field, determine the first light field corresponding to any plane of the first geometric phase multiplane light transformation field through which the cylindrical vector beam field sequentially passes; Based on the fundamental mode Gaussian optical array field and the first geometric phase multiplane optical transformation field, determine the second optical field corresponding to any plane of the first geometric phase multiplane optical transformation field through which the Gaussian optical array field passes in reverse order; Based on the orthogonal basis difference values ​​of the first geometric phase, the first light field, and the second light field, and a preset condition, the second geometric phase corresponding to the preset condition is obtained; Based on the second geometric phase, the multi-plane optical transformation field of the second geometric phase is determined by vector wavefront matching. Based on the second geometric phase multiplane light transformation field, the fundamental mode Gaussian light array field and the cylindrical vector beam field are mutually converted.

2. The method as described in claim 1, characterized in that, The step of obtaining the second geometric phase corresponding to the preset conditions based on the orthogonal basis difference values ​​of the first geometric phase, the first optical field, and the second optical field, and the preset conditions, includes: Based on the first geometric phase, the first light field, and the second light field of any plane, the orthogonal basis difference value of the first light field and the second light field is iteratively calculated until the orthogonal basis difference value satisfies the preset condition; The summation of the orthogonal basis differences is determined by performing a summation operation on the orthogonal basis differences values ​​of each plane of the first geometric phase multiplane optical transformation field that satisfy the preset conditions. Based on the sum of the orthogonal basis vector differences, determine the second geometric phase corresponding to the sum of the orthogonal basis vector differences.

3. The method as described in claim 2, characterized in that, The preset condition is that the orthogonal basis difference value is the minimum value of the orthogonal basis difference value between the first light field and the second light field corresponding to each of the planes.

4. The method as described in claim 2, characterized in that, The formula for calculating the difference of the orthogonal basis vectors is: Wherein, Δ is the difference value of the orthogonal basis vectors; e is the base of the natural logarithm function; j represents phase modulation; i is the index of any plane in the first geometric phase multiplane optical transformation field; Ci is the first light field corresponding to the plane with index i; Gi is the second light field corresponding to the plane with index i; LCP stands for left-handed polarized light; RCP stands for right-handed polarized light; θ1 is the first geometric phase.

5. The method as described in claim 1, characterized in that, The determination of the multi-plane optical transformation field of the second geometric phase based on the second geometric phase using vector wavefront matching includes: Based on the second geometric phase, the vector wavefront matching is sequentially iterated using the argument calculation formula to obtain the third optical field corresponding to any plane of the first optical field propagating to the first geometric phase multiplane optical transformation field. Based on the second geometric phase, the vector wavefront matching is reversed and iterated using the argument calculation formula to obtain the fourth optical field corresponding to any plane of the multi-plane optical transformation field of the first geometric phase propagating from the second optical field. The second geometric phase multiplane optical transformation field is determined based on the third and fourth optical fields corresponding to each of the planes.

6. The method as described in claim 5, characterized in that, The formula for calculating the argument is: Wherein, θ2 is the second geometric phase; Reg is the argument operator; i is the index of any plane in the first geometric phase multiplane optical transformation field; i * It is the index of any plane in the second geometric phase multiplane optical transformation field; Ci is the first light field corresponding to the plane with index i; Gi is the second light field corresponding to the plane with index i; Ci * For the sequence number i * The third light field corresponding to the plane; Gi * For the sequence number i * The fourth light field corresponding to the plane; m is the number of planes in the second geometric phase multiplane optical transformation field; LCP stands for left-handed polarized light; RCP stands for right-handed polarized light.

7. A device for converting optical field vector modes, characterized in that, include: The first acquisition module is used to acquire the cylindrical vector beam field, the fundamental mode Gaussian light array field, and the first geometric phase multiplane light transformation field, wherein any plane in the first geometric phase multiplane light transformation field includes one or more first geometric phases; The first determining module is used to determine, based on the cylindrical vector beam field and the first geometric phase multiplane light transformation field, the first light field corresponding to any plane of the first geometric phase multiplane light transformation field through which the cylindrical vector beam field sequentially passes; The second determining module is used to determine, based on the fundamental mode Gaussian optical array field and the first geometric phase multiplane optical transformation field, the second optical field corresponding to any plane of the first geometric phase multiplane optical transformation field after the Gaussian optical array field passes in reverse order. The second acquisition module is used to acquire the second geometric phase corresponding to the preset conditions based on the first geometric phase, the orthogonal basis difference value of the first light field and the second light field and the preset conditions; The third determining module is used to determine the multi-plane optical transformation field of the second geometric phase based on the second geometric phase using a vector wavefront matching method; The conversion module is used to convert the fundamental mode Gaussian light array field and the cylindrical vector beam field to each other based on the second geometric phase multiplane light transformation field.

8. A communication system for optical field vector mode conversion, characterized in that, It includes a first input / output module, a vector wavefront matching module, a reflector, and a second input / output module; Wherein, the first input / output module is used to receive or output a fundamental mode Gaussian light array field, the second input / output module is used to receive or output a cylindrical vector beam field, the vector wavefront matching module is used to execute the method of any one of claims 1 to 6, and the reflector is used to realize the mutual conversion between the fundamental mode Gaussian light array field and the cylindrical vector beam field.

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