Polarization independent needle light generating system and method

Abstract

This application relates to a polarization-independent needle-shaped light generation system and method, belonging to the field of optical communication technology. The polarization-independent needle-shaped light generation system includes: a light source; and a dual-polarization component, which includes an optical path element and a spatial light modulator. The optical path element is used to split the incident light output from the light source into two polarized lights and convert them into target polarized light modulated by the spatial light modulator. The spatial light modulator is programmed with the complex amplitude of the needle-shaped light to modulate the target polarized light and generate polarization-independent needle-shaped light. This application can process signals with arbitrary polarization states while focusing the incident light into a needle shape, maintaining non-diffraction characteristics within the design range, thereby ensuring the quality of the received signal.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, specifically to a polarization-independent needle-shaped light generation system and method. Background Technology

[0002] In recent years, space optical communication has attracted increasing attention due to its advantages such as high bandwidth, strong security, numerous unlicensed frequency bands, and low cost, and is widely regarded as the next generation of high-speed wireless communication technology. Compared with radio communication, space optical communication has greater potential in campus interconnection, video surveillance, storage area networks, and military access.

[0003] However, current space optical links often use Gaussian light as the carrier. During long-distance propagation, diffraction effects cause the beam to broaden and weaken its peak intensity, leading to significant power loss, mode crosstalk, and signal loss during reception. This is particularly problematic in communication links between ground stations and UAVs / aircraft, where ground stations typically have large transmitting apertures while UAVs / aircraft usually have small receiving apertures. This necessitates a narrow, low-divergence beam that maintains its propagation characteristics over considerable distances. Summary of the Invention

[0004] This application provides a polarization-independent needle-shaped light generation system and method, which can process signals with arbitrary polarization states and focus the incident light into a needle shape while maintaining non-diffraction characteristics within the design range, thereby ensuring the quality of the received signal.

[0005] In a first aspect, embodiments of this application provide a polarization-independent needle-shaped light generation system, the polarization-independent needle-shaped light generation system comprising:

[0006] light source;

[0007] A dual polarization component includes an optical path element and a spatial light modulator. The optical path element is used to split the incident light output from the light source into two polarized lights and convert them into target polarized light that can be modulated by the spatial light modulator. The spatial light modulator is programmed with the complex amplitude of the needle-shaped light to modulate the target polarized light to generate polarization-independent needle-shaped light.

[0008] In conjunction with the first aspect, in one embodiment, the optical path element includes:

[0009] A beam splitter prism is used to receive the incident light output from the light source;

[0010] A polarizing beam splitter, used to split the beam output by the beam splitter into two orthogonally polarized beams;

[0011] A reflector assembly includes a first branch and a second branch. The first branch is provided with a first reflector, which is used to directly input one polarized light into the spatial light modulator. The first branch is provided with a second reflector and a half-wave plate, which is used to input another polarized light into the half-wave plate for conversion, and then input it into the spatial light modulator.

[0012] The reflector assembly is also used to receive the light beam modulated by the spatial light modulator and output it to the lens through the beam splitter.

[0013] In conjunction with the first aspect, in one embodiment, the light source is a collimated light source, which includes a laser and a collimator.

[0014] In conjunction with the first aspect, in one embodiment, the laser is a narrow linewidth external cavity tunable laser.

[0015] In conjunction with the first aspect, in one embodiment, the spatial light modulator is a modulator that modulates only the phase.

[0016] Secondly, embodiments of this application provide a polarization-independent needle-shaped light generation method, the polarization-independent needle-shaped light generation method comprising:

[0017] The dual polarization component is used to split the incident light output from the light source into two polarized lights, and then convert them into target polarized light that can be modulated by the spatial light modulator.

[0018] The spatial light modulator is used to modulate the target polarized light to generate polarization-independent needle-shaped light.

[0019] In conjunction with the second aspect, in one implementation method,

[0020] According to the formula: The phase of the needle-shaped light is written into the spatial light modulator, where k is the wave vector, β is a value related to the design distance, and ρ is the polar distance.

[0021] In conjunction with the second aspect, in one implementation method,

[0022] According to the formula: The amplitude of the needle-shaped light is written into the spatial light modulator, wherein A OPB The parameter is related to the amplitude, ρ is the polar moment, and the amplitude is 0 when the polar moment approaches 0.

[0023] In conjunction with the second aspect, in one embodiment, the spatial light modulator is a modulator that modulates only the phase.

[0024] In conjunction with the second aspect, in one embodiment, a beam-splitting grating is used to ensure that the phase written into the spatial light modulator satisfies:

[0025] in, A is the amplitude. For phase, This represents the grating phase.

[0026] The beneficial effects of the technical solutions provided in this application include:

[0027] The polarization-independent needle-shaped light generation system in this application uses a dual polarization component to split the incident light output from the light source into two polarized lights, and converts them into target polarized light that can be modulated by a spatial light modulator; the target polarized light is modulated by a complex amplitude spatial light modulator with needle-shaped light written on it to generate needle-shaped light.

[0028] This application uses a dual polarization component to split the incident light into two polarized components, processes each component separately, and then combines them. This reduces the impact of polarization on system performance. As a result, signals with arbitrary polarization can be processed, while the incident light is focused into a needle shape, maintaining non-diffraction characteristics within the design range, thus ensuring the quality of the received signal. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0030] Figure 1 This is a structural block diagram of an embodiment of the polarization-independent needle-shaped light generation system of this application;

[0031] Figure 2 This is a schematic diagram of the structure of an embodiment of the dual polarization component of this application;

[0032] Figure 3 This is a schematic diagram illustrating the principle of needle-shaped light generation in this application;

[0033] Figure 4 This is a schematic diagram of the phase superposition of needle-shaped light in this application;

[0034] Figure 5 This is a schematic diagram of the needle-shaped beam space division in this application;

[0035] Figure 6 This is a schematic diagram of the light field intensity at the focusing position of the needle-shaped beam in this application;

[0036] Figure 7 This is a schematic diagram of the light field intensity after the needle-shaped light of this application has been focused for a certain distance;

[0037] Figure 8 This is a flowchart of an embodiment of the polarization-independent needle-shaped light generation method of this application. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0040] In a first aspect, embodiments of this application provide a polarization-independent needle-shaped light generation system.

[0041] In one embodiment, reference is made to Figure 1 , Figure 1 This is a structural block diagram of an embodiment of the polarization-independent needle-shaped light generation system of this application. Figure 1 As shown, the polarization-independent needle-shaped light generation system includes a light source and a dual polarization component.

[0042] The light source is used to output incident light to the dual polarization component. In this embodiment, the light source is a collimated light source. Specifically, the collimated light source includes a laser and a collimator. Preferably, the laser is a narrow linewidth external cavity tunable laser. Of course, other types of lasers can also be selected as needed. This embodiment does not impose any restrictions on this.

[0043] A dual polarization component includes an optical path element and a spatial light modulator. The optical path element is used to split the incident light output from the light source into two polarized lights and convert them into target polarized light that can be modulated by the spatial light modulator. The spatial light modulator is programmed with the complex amplitude of the needle-shaped light to modulate the target polarized light to generate polarization-independent needle-shaped light.

[0044] For details, see Figure 2 As shown, the optical path components include a beam splitter prism, a polarizing beam splitter prism, and a mirror assembly.

[0045] A beam splitter is used to receive the incident light output from the light source, and a polarizing beam splitter is used to split the beam output from the beam splitter into two orthogonally polarized beams.

[0046] The reflector assembly includes a first branch and a second branch. The first branch is provided with a first reflector, which is used to directly input one polarized light into the spatial light modulator. The first branch is provided with a second reflector and a half-wave plate, which is used to input another polarized light into the half-wave plate for conversion, and then input it into the spatial light modulator. The reflector assembly is also used to receive the beam modulated by the spatial light modulator and output it to the lens through a beam splitter.

[0047] It is worth noting that, generally speaking, spatial light modulators can only modulate one polarization state, namely the target polarization state. For the other polarization state that cannot be modulated, a half-wave plate is needed to convert it into usable polarized light.

[0048] It is understood that this embodiment uses a polarizing beam splitter to split the light into two orthogonal polarization components, processes these two components separately, and then combines them. This reduces the impact of polarization on system performance and thus achieves polarization independence.

[0049] The principle of a polarization-independent spatial optical obstacle avoidance system is explained below:

[0050] First, the optical path needs to be adjusted. In this embodiment, a light source with a wavelength of 1550nm is used as an example. Since a 1550nm light source is invisible to the naked eye, when adjusting the dual-polarized optical path, the optical path should first be roughly adjusted using visible light, and then the optical path should be fine-tuned by observing the beam using a CCD (Charge-Coupled Device) to ensure that the dual-polarized light is incident on the same position on the spatial light modulator and that the beams overlap when exiting from the dual-polarized part.

[0051] The specific fine-tuning steps are as follows: First, load a vortex phase onto the spatial light modulator. Place the CCD between the first reflector on the left and the spatial light modulator, and adjust the optical path so that a standard ring can be observed on the CCD. This indicates that the polarized light is at the center of the loaded phase. Then, place the CCD between the second reflector on the right and the spatial light modulator. Repeat the above steps to ensure that the dual-polarized light is incident on the same position on the spatial light modulator. When adjusting the overlap of the outgoing beams, place the CCD between the dual-polarization component and the lens, and adjust the optical path until only one spot is observed on the CCD. Since adjusting the optical path affects the positions of both the incident and outgoing light, the above steps need to be performed multiple times. To verify the accuracy of the final optical path, a polarization controller can be added in front of the collimating source to change the polarization state of the laser. If the outgoing light does not change, it indicates that the system is polarization-independent.

[0052] Needle-shaped beams are generated by radially superimposing Airy-like beams using the principle of caustics. Their transverse wave vectors cancel each other out, and all wave components propagate in the same direction. For a detailed explanation of the generation principle, see [link to documentation]. Figure 3As shown. Needle-shaped light can be directly obtained by phase modulation: Where k is the wave vector, β is a value related to the design distance, and ρ is the polar distance.

[0053] To ensure that the amplitude of the needle-shaped beam remains constant or changes minimally during propagation, its amplitude can be modulated as follows: Among them, A OPB ρ is a parameter related to amplitude, and ρ is the polar moment. Furthermore, since the amplitude diverges as the radius approaches 0, the amplitude within the radius ρ0 is set to 0.

[0054] Current spatial light modulators can only modulate either the phase or the amplitude, not both simultaneously. When using a phase-only spatial light modulator, to simultaneously write both amplitude and phase, the principle of a beam splitter is used to ensure the phase satisfies:

[0055] in, A is the amplitude. For phase, The phase of the grating is represented by Mod, which indicates the remainder.

[0056] For details on the phase superposition process, please refer to Figure 4 As shown, the first image represents the graph of M, the second image represents F, and the third image represents... Addition means The final multiplication represents the required phase: Since the phase has a period of 2π, and The images are the same image.

[0057] Furthermore, a beam splitter can separate two beams of light deflected in any direction, thus performing spatial multiplexing of spatial light and enabling simultaneous signal transmission to multiple targets. The spatial propagation of a needle-shaped beam is as follows: Figure 5 As shown. The light field intensity at the focusing position and after focusing for a certain distance are respectively as follows: Figure 6 and Figure 7 As shown.

[0058] In summary, the polarization-independent needle-shaped light generation system of this application uses a dual polarization component to split the incident light output from the light source into two polarized lights and convert them into target polarized light that can be modulated by a spatial light modulator; the target polarized light is modulated by a complex amplitude spatial light modulator with needle-shaped light written on it to generate needle-shaped light.

[0059] This application uses a dual polarization component to split the incident light into two polarized components, processes each component separately, and then combines them. This reduces the impact of polarization on system performance. As a result, signals with arbitrary polarization can be processed, while the incident light is focused into a needle shape, maintaining non-diffraction characteristics within the design range, thus ensuring the quality of the received signal.

[0060] Secondly, embodiments of this application provide a polarization-independent needle-shaped light generation method.

[0061] In one embodiment, reference is made to Figure 8 , Figure 8 This is a flowchart of an embodiment of the polarization-independent needle-shaped light generation method of this application. Figure 8 As shown, polarization-independent needle-like light generation methods include:

[0062] S1. The incident light output from the light source is split into two polarized lights using the dual polarization component and converted into target polarized light that can be modulated by the spatial light modulator.

[0063] S2. Modulate the target polarized light using the spatial light modulator to generate polarization-independent needle-shaped light.

[0064] Furthermore, in one embodiment,

[0065] According to the formula: The phase of the needle-shaped light is written into the spatial light modulator, where k is the wave vector, β is a value related to the design distance, and ρ is the polar distance.

[0066] Furthermore, in one embodiment,

[0067] According to the formula: The amplitude of the needle-shaped light is written into the spatial light modulator, wherein A OPB The parameter is related to the amplitude, ρ is the polar moment, and the amplitude is 0 when the polar moment approaches 0.

[0068] Furthermore, in one embodiment, the spatial light modulator is a modulator that modulates only the phase.

[0069] Furthermore, in one embodiment, a beam-splitting grating is used to ensure that the phase written into the spatial light modulator satisfies:

[0070] in, A is the amplitude. For phase, This represents the grating phase.

[0071] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0072] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0073] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A polarization independent needle light generating system, characterized by, The polarization-independent needle-shaped light generation system includes: light source; A dual polarization component includes an optical path element and a spatial light modulator. The optical path element is used to split the incident light output from the light source into two polarized lights and convert them into target polarized light that can be modulated by the spatial light modulator. The spatial light modulator is programmed with the complex amplitude of the needle-shaped light to modulate the target polarized light to generate polarization-independent needle-shaped light. The spatial light modulator is configured as follows: According to the formula: The phase of the needle-shaped light is written into the spatial light modulator, wherein, For wave vector, Values ​​related to the design distance, The polar distance; Furthermore, the spatial light modulator is a modulator that modulates only the phase, and the phase written into the spatial light modulator satisfies: ,in, , For amplitude, , For phase, For grating phase; Among them, amplitude satisfy: , For parameters related to amplitude, The polar distance is denoted as , and the amplitude is 0 when the polar distance approaches 0.

2. The polarization-independent needle-shaped light generation system as described in claim 1, characterized in that, The optical path element includes: A beam splitter prism is used to receive the incident light output from the light source; A polarizing beam splitter, used to split the beam output by the beam splitter into two orthogonally polarized beams; A reflector assembly includes a first branch and a second branch. The first branch is provided with a first reflector, which is used to directly input one polarized light into the spatial light modulator. The second branch is provided with a second reflector and a half-wave plate, which is used to input another polarized light into the half-wave plate for conversion, and then input it into the spatial light modulator. The reflector assembly is also used to receive the light beam modulated by the spatial light modulator and output it to the lens through the beam splitter.

3. The polarization-independent needle-shaped light generation system as described in claim 1, characterized in that: The light source is a collimated light source, which includes a laser and a collimator.

4. The polarization-independent needle-shaped light generation system as described in claim 3, characterized in that: The laser is a narrow-linewidth external cavity tunable laser.

5. A polarization-independent needle-shaped light generation method using the polarization-independent needle-shaped light generation system of claim 1, characterized in that, The polarization-independent needle-like light generation method includes: The dual polarization component is used to split the incident light output from the light source into two polarized lights, and then convert them into target polarized light that can be modulated by the spatial light modulator. The spatial light modulator is used to modulate the target polarized light to generate polarization-independent needle-shaped light.

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