A one-dimensional 2 n Controllable fiber beam splitter with square root dimer topology

Abstract

This invention discloses a method based on one-dimensional 2D n A controllable fiber beam splitter with a square root dimer topology. The 2 n The topological properties of the square-root dimer chain topology are inherited from the square Hamiltonian. By inserting additional sites into the original model, it is possible to achieve 2 n There are _n_, which are _n_, any natural number, representing _n_, a topological boundary state. The one-dimensional 2_n described in this invention... n A square root diplex fiber splitter is a type of fiber core splitter with a one-dimensional 2D structure. n The microstructured optical fiber with a periodically arranged square root dimer chain topology can split a single incident laser beam for output. The number of boundary states in this invention can be adjusted by the value of n, achieving an adjustable beam splitting effect. Furthermore, the optical signal propagation in the topologically protected boundary core is stable. This invention represents a practical combination of topology and photonic devices, and holds promise for applications in optical communication, optical sensing, and optical quantum computing.

Description

Technical Field

[0001] This invention belongs to the field of topological photonic crystal fiber applications, specifically relating to a one-dimensional 2D optical fiber... n A controllable fiber beam splitter with a square root dimer topology. Background Technology

[0002] In the development of optical devices, light transmission and manipulation are important research areas. Optical topological insulators have attracted widespread attention due to their topologically protected light transmission and localization effects, which are immune to disorder and defects, as well as their novel light field manipulation mechanisms.

[0003] Currently, photonic topological insulators have been realized in optical systems such as coupled waveguide arrays and pure dielectric cavities. However, these studies mostly focus on theoretical analysis and discussion of the topological properties of the topological structure, and the exploration of photonic topological insulators still lacks application-level support. As the simplest and most common optical system, optical coupled waveguide arrays, when combined with topological band theory, exhibit significant robustness of their boundary states to structural disorder and defects, and can be applied to the construction of optical beamsplitters.

[0004] Optical beamsplitters are devices that split input light into several output beams, and are widely used in optical communication systems, passive optical networks, and other systems. The coupling performance of traditional beamsplitters is often affected by high structural sensitivity; therefore, solving this problem places higher demands on the precision of micro- and nano-fabrication, posing a significant challenge to existing manufacturing technologies. Significant efforts have been made to address this long-standing problem, for example, by utilizing the compensation process of Mach-Zehnder interferometers and the design of adiabatic channels to improve accuracy. However, these methods typically require external intervention or stringent parameter conditions, which not only places high demands on processing equipment but also poses challenges to large-scale manufacturing.

[0005] In the study of optical beamsplitters, researchers have employed various methods to improve and optimize their performance. The patent CN113917685A, "A Design Scheme for Optical Waveguide Splitting Based on Energy-Oriented Coupling," is characterized by adjusting the splitting ratio of the coupling region by controlling the relative positions and coupling lengths of the various parts between the waveguides. However, the aforementioned waveguide beamsplitter still requires high processing precision; errors in the coupling length and spacing can affect the coupling effect, thus impacting the splitting performance. Summary of the Invention

[0006] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the purpose of this invention is to provide a one-dimensional 2D model. nA fiber beam splitter with a square root dimer topology has boundary state properties protected by the topology. The beam splitting effect is less affected by structural parameter errors and defects. Furthermore, structures with different n values ​​can achieve adjustable beam splitting effects, which is expected to be used in integrated optical path components.

[0007] The objective of this invention is achieved by at least one of the following technical solutions.

[0008] A one-dimensional 2 n A controllable fiber splitter with a square root dimer topology includes a cladding and multiple fiber cores disposed within the cladding. The multiple fiber cores are arranged at a set period of 2... n The square root dimer chain topology is arranged, where n is any natural number, and the value of n determines the number of beams split by the fiber optic beam splitter.

[0009] The 2 n In the square root dimer topology, the cores are arranged periodically, and the number of cores in each period is adjustable, determined by the value of n. The number of cores in a unit period is 2. n+1 indivual;

[0010] The 2 n In the square root dimer chain topology, for the same value of n, the coupling between units of time and the coupling between fiber cores within a unit of time are divided into strong coupling and weak coupling. The coupling coefficients for weak coupling are the same, and the coupling coefficients for strong coupling are also the same.

[0011] Furthermore, the one-dimensional 2 n In the square root dimer chain topology, when n>0, the fiber core is repeatedly arranged in one direction according to a set period, and the number of periods is greater than or equal to 2.

[0012] When n=0, one-dimensional 2 n The square root dimer chain topology is composed of a combination of topologically nontrivial and topologically trivial phases of one-dimensional dimer chains, with the combination of the two topological phases being a phase transition interface. The fiber cores are first arranged according to the topologically nontrivial phases to set the period, and then arranged according to the topologically trivial phases to set the period. After the last period, there is a fiber core that is weakly coupled to the previous fiber core. The topologically nontrivial and topologically trivial phases are combined with weak coupling. The topologically nontrivial phases have one less period than the topologically trivial phases, and the topologically nontrivial phases have a period greater than or equal to 2.

[0013] Furthermore, when n=0, the core arrangement in the topologically nontrivial phase is as follows: the cores are weakly coupled to each other within a unit period and strongly coupled to each other within a unit period; the core arrangement in the topologically trivial phase is as follows: the cores are strongly coupled to each other within a unit period and weakly coupled to each other within a unit period.

[0014] Furthermore, the one-dimensional 2 nIn the square root dimer topology, the core distribution within each period is adjusted according to the number n, as follows:

[0015] When n>0, within a unit period, the first 2 n The coupling coefficients between each fiber core are equal, and the coupling coefficients per unit period are the same as those of the previous two. n The coupling coefficients between the individual fiber cores are equal, indicating strong coupling; the second n The fiber core to the 2nd n+1 The coupling coefficients between the individual fiber cores are equal, indicating weak coupling.

[0016] For all unit periods, the first 2 n The coupling coefficients between each fiber core and the coupling coefficient per unit period are equal; the second n The fiber core to the 2nd n+1 The coupling coefficients between each fiber core are equal.

[0017] Furthermore, the coupling parameters between the fiber cores satisfy:

[0018]

[0019] L c Where t is the coupling length and t is the coupling coefficient;

[0020] When n = 0, in the topological non-trivial phase, the coupling coefficient of the fiber core within all unit periods is t1, and the coupling coefficient between all unit periods is t2;

[0021] When n = 0, in the topologically trivial phase, the coupling coefficient of the core within all unit periods is t2, the coupling coefficient between all unit periods is t1, and the coupling coefficient between the last core and the previous core is t1.

[0022] When n>0, the first 2 in all periods n The coupling coefficient of each fiber core and the coupling coefficient between units of period are t3, the second... n The fiber core to the 2nd n+1 The coupling coefficient of each fiber core is t4;

[0023] Solving one-dimensional 2D problems using the above coupling coefficients n The eigenvalues ​​of the Hamiltonian H of the square-root dimer topology are used to obtain a one-dimensional 2 n For the band structure of the square root dimer chain topology, when the band structure exhibits topological edge states, the specific parameters of the coupling coefficient are determined, and then the coupling spacing between the fiber cores is obtained according to the above formula.

[0024] Furthermore, the one-dimensional 2 n In the square root dimer chain topology, when n=0, the one-dimensional 2 nIn the square-root dimer chain topological structure, the first and the last fiber cores are edge fiber cores; at the phase transition interface, fiber cores that are weakly coupled with both the previous and the next fiber cores are interface fiber cores;

[0025] When n>0, the first 2 n fiber cores are edge fiber cores.

[0026] Further, the optical fiber splitter has a plurality of input ends and output ends;

[0027] When n=0, one end of the interface fiber core is the input end of the optical fiber splitter, and light enters from the interface fiber core; the other end of the edge fiber core is the output end of the optical fiber splitter, and the number of edge fiber cores is equal to the beam splitting number;

[0028] When n>0, one end of the edge fiber core is the input end of the optical fiber splitter, and light enters from the edge fiber core; the other end of the edge fiber core is the output end of the optical fiber splitter, and the number of edge fiber cores is equal to the beam splitting number.

[0029] Further, the input end of the optical fiber splitter couples the laser into the edge fiber core through a microscope objective and an optical fiber, the split laser can be obtained at the output end of the optical fiber splitter, and the output end can be connected to receivers such as a microscope objective and a camera.

[0030] Further, the fiber core of the optical fiber splitter transmits single-mode laser.

[0031] Further, the wavelength of the incident single-mode laser is selected from the visible to near-infrared range.

[0032] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0033] In the one-dimensional 2 n square-root dimer chain topological structure, the energy band of the topological structure is given by the eigenvalue of its Hamiltonian. Taking n=1 as an example, the energy band structure is:

[0034]

[0035] t1 is the coupling coefficient between the first 2 n fiber cores in a unit period and between adjacent periods, t2 is the coupling coefficient from the 2 n th fiber core to the 2 n+1 th fiber core and between adjacent periods, and k is the Bloch vector. When the coupling coefficient between fiber cores changes from t1=t1 to t1≠t1, the energy band structure changes from closed to open, and 2 n band gaps appear. When the system has a finite period and t1<t1, protected edge states will appear in each band gap, that is, the topological structure has 2 n edge states. Specifically, 2 nIn each fiber core, when light enters from any edge core, it will be localized at the edge. n Coupled transmission within each fiber core enables stable and tunable beam splitting.

[0036] Based on this topological theory, this invention has the following characteristics:

[0037] (1) In this invention, the edge fiber core is topologically protected and has boundary states that are resistant to disturbances and disorder. Compared with traditional beam splitters, even if the topological parameters of this invention have errors and defects within a certain range, the edge fiber core can still have good optical localization effects and relatively high process tolerance;

[0038] (2) This invention provides a series of topological structures. By adjusting the value of n, different topological structures have different numbers of boundary states, which can achieve an adjustable number of spectral dispersion effects and have scalability.

[0039] (3) The present invention can adjust the size of the beam splitter structure by adjusting the number of cell periods. Since the optical fiber has a certain degree of flexibility, the size and arrangement of the beam splitter can be adjusted according to the actual application background, which is beneficial to the integration of photonic devices.

[0040] (4) In this invention, by changing the fiber length and fiber spacing, the coupling effect between fiber cores is tuned to obtain different beam splitting ratios and achieve the beam splitting effect. Attached Figure Description

[0041] Figure 1 As in Example 1, based on one-dimensional 2D n A schematic diagram of a fiber optic beam splitter with a square root dimer chain topology;

[0042] Figure 2 This is a schematic diagram of the cross-sectional structure of the fiber optic beam splitter based on a one-dimensional binary chain topology in Example 1;

[0043] Figure 3 This is a simulated data diagram of laser propagation within an optical fiber beam splitter based on a one-dimensional binary chain topology in Example 1;

[0044] Figure 4 This is a mode field distribution diagram of the output end face of the fiber beam splitter based on a one-dimensional binary chain topology in Example 1;

[0045] Figure 5 This is a schematic diagram of the cross-sectional structure of the fiber optic beam splitter based on a one-dimensional square root dimer chain topology in Example 2.

[0046] Figure 6 This is a simulated data diagram of laser propagation within an optical fiber beam splitter based on a one-dimensional square root dichotomous chain topology in Example 2.

[0047] Figure 7 This is a mode field distribution diagram of the output end face of the fiber beam splitter based on a one-dimensional square root dichotomous chain topology in Example 2;

[0048] Figure 8 This is a schematic diagram of the cross-sectional structure of the fiber beam splitter based on the one-dimensional root-fourth-order dimer chain topology in Example 3.

[0049] Figure 9 This is a simulated data diagram of laser propagation within an optical fiber beam splitter based on a one-dimensional root-fourth-order dimer chain topology in Example 3.

[0050] Figure 10 This is a mode field distribution diagram of the output end face of the fiber beam splitter based on a one-dimensional root-fourth-order dimer chain topology in Example 3. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0052] Example 1:

[0053] A one-dimensional 2 n Fiber beam splitter with square root dimer chain topology:

[0054] like Figure 1 As shown, taking n=1 as an example, the fiber optic bundle splitter includes a cladding region 1 and a core region 2. In the core region 2, the fiber core is arranged in a one-dimensional 2D configuration. n Square root dimer chain topological arrangement; 2 n In a square root dimer chain structure, the topological properties of the daughter chain are inherited from the parent chain, possessing 2 n A topologically protected boundary state. 2 n The construction rules of square root dimer chain structures, in 2 n-1 Based on the square root dimer chain structure, new fiber cores are inserted between adjacent fiber cores. When the input laser 3 is incident from the edge fiber core, it will be locally coupled and transmitted within the edge fiber core. When the value of n takes different natural numbers, different topologies can be obtained, achieving different beam splitting effects, resulting in the output laser 4.

[0055] When n = 0, the specific implementation effect is as follows:

[0056] like Figure 2as shown in the figure, is a schematic cross-sectional structure diagram of an optical fiber beam splitter based on a one-dimensional dimer chain topological structure. The dashed box represents one period, and each period consists of 2 fiber cores. In this topological structure, when d1≠d2, the system bandgap opens; under the condition of finite periods, when d1>d2, it is a topologically non-trivial phase, and topologically protected zero-energy edge states exist in the bandgap; when d1<d2, it is a topologically trivial phase. To achieve the optical beam splitting effect, an interface structure is introduced into the traditional one-dimensional dimer chain structure, which is composed of a combination of the topologically non-trivial phase and the topologically trivial phase, Figure 2 the dashed box P in N is the periodic structure of the topologically non-trivial phase, and P T is the periodic structure of the topologically trivial phase. The topological invariant changes at the transition between the two phases, forming a phase transition interface, and at this time, three zero-energy topological edge states exist in the band structure of the system. The specific structure is as follows: taking five periods as an example in the figure, the core spacing within each period in the topologically non-trivial phase is d1, the period spacing is d2, and the number of periods is 3; the core spacing within each period in the topologically trivial phase is d2, the period spacing is d1, and the number of periods is 2, and the last part of the structure is a weakly coupled fiber core. When light is incident from the interface fiber core (M), directional alternating coupling will be realized between these three fiber cores.

[0057] In this embodiment, the beam splitting effect of the optical fiber beam splitter based on the one-dimensional dimer chain topological structure is simulated through simulation experiments. The specific parameters are as follows: the refractive index difference between the fiber core and the cladding is 0.0035, the fiber core diameter is 5μm, the wavelength of the incident laser is 1030nm, the propagation distance is 4.5cm, and the coupling spacing between the fiber cores is d1=10μm (t1=5.28cm -1 ), d2=6μm (t2=23.80cm -1 ). Figure 3 and Figure 4 are respectively the simulation data diagram of the incident laser propagating inside the optical fiber beam splitter and the mode field distribution diagram of the output end face of the optical fiber beam splitter. As shown in Figure 3 , in the one-dimensional dimer chain topological structure, the laser is incident from the interface fiber core (M), and the incident single 1030nm laser is equally divided into two beams after coupling, which are respectively coupled into the edge fiber cores A and B, and the propagation law of light in A and B is consistent. After a certain distance of coupling transmission, as shown in Figure 4 , the output end face of the optical fiber beam splitter only observes light in the A and B fiber cores, realizing the beam splitting effect. Since the edge fiber cores are topologically protected, the fiber core parameters can have errors within a certain range.

[0058] Embodiment 2

[0059] An optical fiber beam splitter based on a one-dimensional 2 n square root dimer chain topological structure, when n=1, the specific implementation effect is as follows:

[0060] The structure of the optical fiber beam splitter in this embodiment is basically consistent with that described in Embodiment 1, in which the cores in the core layer region are arranged according to the one-dimensional square root dimer chain topology, and its schematic cross-sectional structure is as shown in Figure 5 as shown. The dashed box represents one period, and each period consists of 4 cores, which are arranged periodically in one direction. In this topology, when d1≠d2, the system energy band opens, and two band gaps appear. Under the condition of finite periods, when d1<d2, topologically protected edge states exist in each band gap, and edge states appear in the first 2 cores of the one-dimensional square root dimer chain. The specific structure is as follows: three periods are taken as an example in the figure, the spacing between the first two cores in each period is d1, the spacing between the second and fourth cores is d2, and the spacing between periods is d1. When light is incident from any edge core (A or B) of the one-dimensional square root dimer chain, it will be coupled and transmitted between the edge cores, and the beam splitting ratio of different outputs can be realized by adjusting the propagation length and the coupling spacing.

[0061] In this embodiment, the beam splitting effect of the optical fiber beam splitter based on the one-dimensional square root dimer chain topology is simulated through simulation experiments. The specific parameters are: the refractive index difference between the core and the cladding is 0.00338, the core diameter is 6μm, the incident laser wavelength is 830nm, the propagation distance is 2cm, and the coupling spacing between cores is d1=8μm (t1=7.36cm -1 ), d2=12μm (t2=0.74cm -1 ). Figure 6 and Figure 7 are respectively the simulation data diagram of the incident laser propagating in the optical fiber beam splitter and the mode field distribution diagram of the output end face of the optical fiber beam splitter, where A is the input end. As shown in Figure 6 as shown, the incident single 830nm laser is coupled and transmitted between the edge cores (A and B). After 2cm of coupling transmission, the beam splitting ratio between A and B is close to 4:6, and the output end face is as shown in Figure 7 as shown. Since the edge cores are topologically protected, the core spacing can have errors within a certain range.

[0062] Embodiment 3

[0063] An optical fiber beam splitter based on a one-dimensional 2 n root dimer chain topology, when n=2, the specific implementation effects are as follows:

[0064] The structure of the optical fiber beam splitter in this embodiment is basically consistent with that described in Embodiment 1, in which the cores in the core layer region are arranged according to the one-dimensional fourth root dimer chain topology, and its schematic cross-sectional structure is as shown in Figure 8as shown. The dashed box represents one period, each period consists of 8 fiber cores, which are arranged periodically in one direction. In this topology, when d1≠d2, the system band is opened with four band gaps. Under the finite period condition, when d1<d2, topologically protected edge states exist in each band gap, and edge states appear in the first 4 fiber cores of the one-dimensional quartic root dimer chain. The specific structure is as follows: the figure takes two periods as an example, the spacing between the first four fiber cores in each period is d1, the spacing between the fourth and the eighth waveguide is d2, and the spacing between periods is d1. When light is incident from any edge fiber core (A, B, C or D) of the one-dimensional quartic root dimer chain, it will be coupled and transmitted between the edge fiber cores, and the splitting ratios of different outputs can be realized by adjusting the propagation length and coupling spacing.

[0065] In this embodiment, the light splitting effect of the optical fiber splitter based on the one-dimensional quartic root dimer chain topology is simulated through simulation experiments. The specific parameters are as follows: the refractive index difference between the fiber core and the cladding is 0.00338, the fiber core diameter is 6μm, the incident laser wavelength is 830nm, the propagation distance is 4cm, and the coupling spacing between fiber cores is d1=8μm (t1=7.36cm -1 ), d2=12μm (t2=0.74cm -1 ). Figure 9 and Figure 10 are respectively the simulation data diagram of the incident laser propagating in the optical fiber splitter and the mode field distribution diagram of the output end face of the optical fiber splitter, where A is the input end. As shown in Figure 9 , the incident single 830nm laser is coupled and transmitted between the edge fiber cores (A, B, C, D), achieving a larger number of laser splitting effects. After a certain distance of coupling transmission, the output end face of the optical fiber splitter is as shown in Figure 10 , light is observed in the four fiber cores A, B, C and D, realizing the light splitting effect. Since the edge fiber cores are topologically protected, the fiber core spacing can have errors within a certain range.

[0066] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations and simplifications made without departing from the spirit and essence of the present invention shall be equivalent replacement modes and are all included in the protection scope of the present invention.

Claims

1. A method based on one-dimensional A controllable fiber optic beam splitter with a square root dimer topology, characterized in that: It includes a cladding layer and multiple fiber cores disposed within the cladding layer, the multiple fiber cores being arranged according to a set period. Square root dimer chain topological arrangement n For any natural number, n The value of determines the number of beams split by the fiber optic beam splitter; The In the square root dimer chain topology, the cores are arranged periodically, and the number of cores in each period is adjustable. n The value determines the number of fiber cores included within a unit period. indivual; The In the square root dimer chain topology, for the same value of n, the coupling between units of time and the coupling between fiber cores within a unit of time are divided into strong coupling and weak coupling. The coupling coefficients for weak coupling are the same, and the coupling coefficients for strong coupling are also the same.

2. A method based on one-dimensional... A controllable fiber optic beam splitter with a square root dimer topology, characterized in that: The one-dimensional In the square root dimer chain topology, when n>0, the fiber core is repeatedly arranged in one direction according to a set period, and the number of periods is greater than or equal to 2. When n=0, one-dimensional The square root dimer chain topology is composed of a combination of topologically nontrivial and topologically trivial phases of one-dimensional dimer chains, with the combination of the two topological phases being a phase transition interface. The fiber cores are first arranged according to the topologically nontrivial phases to set the period, and then arranged according to the topologically trivial phases to set the period. After the last period, there is a fiber core that is weakly coupled to the previous fiber core. The topologically nontrivial and topologically trivial phases are combined with weak coupling. The topologically nontrivial phases have one less period than the topologically trivial phases, and the topologically nontrivial phases have a period greater than or equal to 2.

3. A method based on one-dimensional... A controllable fiber optic beam splitter with a square root dimer topology, characterized in that: When n=0, the core arrangement in the topologically nontrivial phase is as follows: the cores are weakly coupled to each other within a unit period and strongly coupled to each other within a unit period; the core arrangement in the topologically trivial phase is as follows: the cores are strongly coupled to each other within a unit period and weakly coupled to each other within a unit period.

4. A method based on one-dimensional... A controllable fiber optic beam splitter with a square root dimer topology, characterized in that: The one-dimensional In the square root dimer chain topology, the core distribution within each cycle is based on n The quantity has been adjusted as follows: When n>0, within a unit period, the first The coupling coefficients between each fiber core are equal, and the coupling coefficients per unit period are the same as those of the previous core. The coupling coefficients between the individual fiber cores are equal, indicating strong coupling; the first... The fiber core to the first The coupling coefficients between the individual fiber cores are equal, indicating weak coupling. For all unit periods, the preceding The coupling coefficients between each fiber core and the coupling coefficients per unit period are equal; The fiber core to the first The coupling coefficients between each fiber core are equal.

5. A method based on one-dimensional... A controllable fiber optic beam splitter with a square root dimer topology, characterized in that: The coupling parameters between fiber cores satisfy: Where t is the coupling length and t is the coupling coefficient; When n=0, in the topologically non-trivial phase, the coupling coefficient of the fiber core within all unit periods is: The coupling coefficient between all unit periods is ; When n=0, in the topologically trivial phase, the coupling coefficient of the fiber core within all unit periods is: The coupling coefficient between all unit periods is The coupling coefficient between the last fiber core and the previous fiber core is ; When n>0, the first of all cycles The coupling coefficient of each fiber core and the coupling coefficient between units of period are: , No. The fiber core to the first The coupling coefficient of each fiber core is ; Solving one-dimensional problems using the aforementioned coupling coefficients. Square root dimer chain topology Hamiltonian The eigenvalues ​​are used to obtain a one-dimensional... For the band structure of the square root dimer chain topology, when the band structure exhibits topological edge states, the specific parameters of the coupling coefficient are determined, and then the coupling spacing between the fiber cores is obtained according to the above formula.

6. A method based on one-dimensional... A controllable fiber optic beam splitter with a square root dimer topology, characterized in that: The one-dimensional In the square root dimer chain topology, when n=0, it is a one-dimensional... In the square root dimer chain topology, the first and last fiber cores are edge fiber cores; at the phase transition interface, the fiber cores that are weakly coupled to both the preceding and following fiber cores are interface fiber cores. When n>0, the previous Each fiber core is an edge fiber core.

7. A method based on one-dimensional... A controllable fiber optic beam splitter with a square root dimer topology, characterized in that: The fiber optic beam splitter has multiple input and output terminals; When n=0, one end of the interface fiber core is the input end of the fiber beam splitter, and light enters from the interface fiber core; the other end of the edge fiber core is the output end of the fiber beam splitter, and the number of edge fiber cores is equal to the number of beam splits. When n>0, one end of the edge fiber core is the input end of the fiber optic beam splitter, and light enters from the edge fiber core; the other end of the edge fiber core is the output end of the fiber optic beam splitter, and the number of edge fibers is equal to the number of beams split.

8. A method based on one-dimensional... A controllable fiber optic beam splitter with a square root dimer topology, characterized in that: The input end of the fiber optic beam splitter couples the laser into the edge core through a microscope objective and an optical fiber. The split laser beam can be obtained at the output end of the fiber optic beam splitter, which can be connected to a microscope objective and a camera.

9. A method based on one-dimensional... A controllable fiber optic beam splitter with a square root dimer topology, characterized in that: The fiber core of the fiber splitter transmits single-mode laser light.

10. A method based on one-dimensional... A controllable fiber optic beam splitter with a square root dimer topology, characterized in that: The incident single-mode laser wavelength is selected from the visible to near-infrared range.

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