A full solid-state anti-resonant optical fiber having an arcuate open ring structure

Abstract

The application provides a full solid anti-resonance optical fiber with an arc-shaped opening ring structure, comprising a fiber core, a first anti-resonance layer, a second anti-resonance layer, a cladding region and an outer sleeve, wherein the fiber core is circular, the first anti-resonance layer surrounds the fiber core, and the second anti-resonance layer surrounds the first anti-resonance layer; the first anti-resonance layer and the second anti-resonance layer comprise anti-resonance elements, the cladding region is a matrix material region in the optical fiber structure except the fiber core, and the outer sleeve is an outermost sleeve wrapping the optical fiber structure. The first anti-resonance layer and the second anti-resonance layer comprise anti-resonance elements with multiple arc-shaped openings; or the first anti-resonance layer is a circular ring type anti-resonance unit, and the second anti-resonance layer adopts an arc-shaped opening anti-resonance unit. The full solid anti-resonance optical fiber with the arc-shaped opening ring structure has better single mode characteristics (higher high-order mode suppression ratio) and a smaller fiber outer diameter under the same fiber core size.

Description

Technical Field

[0001] This invention relates to the field of optical fiber technology, and in particular to an all-solid-state anti-resonant optical fiber with an arc-shaped open ring structure. Background Technology

[0002] High-power fiber lasers require gain fibers with large mode area and single-mode transmission characteristics. Large mode area fibers can effectively reduce the optical power density at the fiber end face, thereby suppressing fiber nonlinear effects and increasing the fiber damage threshold. Strict single-mode transmission can suppress multimode competition, improving the beam quality and temperature characteristics of the laser output. High-power fiber lasers, with their outstanding advantages such as high beam quality, high efficiency, low heat generation, and compact structure, are widely used in advanced manufacturing, laser defense, energy exploration, and space science. As laser output power continues to increase, the nonlinear effects and fiber damage problems brought about by high power are becoming increasingly prominent, becoming the main obstacle limiting further increases in fiber laser power. Large mode area fibers can significantly reduce the optical power density in the fiber core, thereby suppressing nonlinear effects and reducing fiber thermal damage. However, as the mode area continues to increase, the number of modes transmitted in the core also increases, causing beam quality degradation. Therefore, large mode area fibers with strict single-mode characteristics have attracted close attention.

[0003] All-solid-state anti-resonant fiber is a novel type of special optical fiber based on an anti-resonant light guiding mechanism. Intuitively, the anti-resonant light guiding mechanism enhances the reflection of incident light when it encounters the cladding dielectric wall, allowing light waves that do not meet the resonance condition to be confined and propagated within the fiber core. The resonant wavelength is related to the dielectric wall thickness and refractive index, and can be expressed as... Where d is the thickness of the anti-resonant layer, n2 and n1 are the refractive indices of the anti-resonant layer and the fiber core, respectively, and m is a positive integer. By adjusting the thickness and refractive index of the anti-resonant layer, anti-resonant fibers can not only achieve ultra-wide transmission bandwidth but also allow the operating wavelength to be designed in any band. In addition, anti-resonant fibers are also easy to implement with large core diameter (large mode area) and single-mode transmission, and many advantages have been proven in hollow-core anti-resonant fibers.

[0004] The emergence of all-solid-state antiresonant fiber has provided a new direction for the development of large mode area fiber. In 2021, Xing Zhen et al. demonstrated the feasibility of realizing single-mode, large mode area fiber based on all-solid-state antiresonant fiber. However, as the mode area increases, the single-mode characteristics of all-solid-state antiresonant fiber deteriorate, and the fiber outer diameter also reaches the centimeter level, causing the fiber to lose its advantages of being slender and flexible, and thus failing to meet the application requirements of miniaturized fiber lasers. Summary of the Invention

[0005] This invention provides an all-solid-state anti-resonant optical fiber with an arc-shaped open ring structure, which effectively solves the problems of poor single-mode characteristics of large-mode-area all-solid-state anti-resonant optical fibers and excessively large outer diameters that are not conducive to laser miniaturization.

[0006] To achieve the above objectives, the present invention adopts the following technical solution.

[0007] An all-solid-state antiresonant optical fiber with an arc-shaped open-loop structure, comprising:

[0008] The fiber consists of a core (1), a first anti-resonant layer (2), a second anti-resonant layer (3), a cladding region (4), and an outer sleeve (5). The core (1) is circular. The first anti-resonant layer (2) surrounds the core (1), and the second anti-resonant layer (3) surrounds the first anti-resonant layer (2). The anti-resonant elements in the first anti-resonant layer (2) and the second anti-resonant layer (3) are arranged in an axially symmetrical manner. The cladding region (4) is the matrix material region in the optical fiber structure other than the core (1). The outer sleeve is the outermost sleeve that wraps around the optical fiber structure.

[0009] Preferably, the first anti-resonant layer (2) and the second anti-resonant layer (3) include anti-resonant elements with multiple arc-shaped openings; or, the first anti-resonant layer (2) is a ring-shaped anti-resonant unit, and the second anti-resonant layer (3) is an anti-resonant unit with arc-shaped openings.

[0010] Preferably, the anti-resonant elements of the first anti-resonant layer (2) and the second anti-resonant layer (3) have the same thickness and opening angle, but different sizes.

[0011] Preferably, the fiber core (1) and the cladding region (4) are made of pure silicon dioxide material.

[0012] Preferably, the first anti-resonance layer (2), the second anti-resonance layer (3), and the outer tube (5) are made of high-refractive-index silicon dioxide material.

[0013] Preferably, the anti-resonant elements in the first anti-resonant layer (2) and the second anti-resonant layer (3) do not contact each other, and the distance between adjacent anti-resonant elements in the first anti-resonant layer and the second anti-resonant layer is 1μm to 10μm.

[0014] Preferably, the opening size of the anti-resonant element in the first anti-resonant layer (2) and the second anti-resonant layer (3) ranges from 0° to 180°, and the thickness is from 700nm to 1700nm.

[0015] As can be seen from the technical solution provided by the present invention, the all-solid-state anti-resonant optical fiber with an arc-shaped open ring structure of the present invention has better single-mode characteristics (higher higher-order mode suppression ratio) and smaller fiber outer diameter under the same core size.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A structural diagram of an all-solid-state anti-resonant optical fiber with an arc-shaped open ring structure provided in an embodiment of the present invention;

[0019] Figure 2 A schematic diagram illustrating the influence of the aperture size of an anti-resonant element on the single-mode characteristics of an optical fiber, provided as an embodiment of the present invention;

[0020] Figure 3 A schematic diagram illustrating the effect of fiber core diameter on single-mode properties provided in an embodiment of the present invention;

[0021] Figure 4 This is a structural diagram of a replacement scheme for an all-solid-state anti-resonant optical fiber with an arc-shaped open ring structure, provided in an embodiment of the present invention. Detailed Implementation

[0022] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0023] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0024] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0025] To facilitate understanding of the embodiments of the present invention, the following will provide further explanation and description with reference to the accompanying drawings and several specific embodiments. These embodiments do not constitute a limitation on the embodiments of the present invention.

[0026] The present invention provides a structure for an all-solid-state anti-resonant optical fiber with an arc-shaped open ring structure, as shown in the embodiment of the invention. Figure 1 As shown, it includes a fiber core 1, a first anti-resonant layer 2, a second anti-resonant layer 3, a cladding region 4, and an outer tube 5. The fiber core region is circular, with the first anti-resonant layer (2) surrounding the fiber core (1), and the second anti-resonant layer (3) surrounding the first anti-resonant layer (2). Both the first and second anti-resonant layers are composed of six arc-shaped anti-resonant elements, and the two anti-resonant elements have the same thickness and opening angle except for their different sizes. The cladding region is the matrix material region outside the fiber core, excluding the high-refractive-index anti-resonant layer and the outer tube. The outer tube is the outermost sleeve that wraps around the optical fiber structure.

[0027] Preferably, the core and cladding regions are made of pure silicon dioxide material.

[0028] Preferably, the first anti-resonance layer, the second anti-resonance layer, and the outer sleeve are made of high-refractive-index silicon dioxide material, such as germanium-doped silicon dioxide.

[0029] Preferably, the anti-resonant elements in the first anti-resonant layer and the second anti-resonant layer do not contact each other. The anti-resonant elements in the first anti-resonant layer (2) and the second anti-resonant layer (3) are arranged in an axially symmetrical manner.

[0030] Preferably, the opening size of the anti-resonant element in the first and second anti-resonant layers ranges from 0° to 180°.

[0031] Preferably, the thickness of the anti-resonant element in the first and second anti-resonant layers is 700 nm to 1700 nm.

[0032] Preferably, the distance between adjacent anti-resonant elements in the first and second anti-resonant layers is 1 μm to 10 μm.

[0033] Figure 2This diagram illustrates the effect of the aperture size of an anti-resonant element on the single-mode characteristics of an optical fiber, as provided in an embodiment of the present invention. Single-mode characteristics are typically measured using the High-order Mode Extinction Ratio (HOMER). HOMER is the ratio of the lowest-loss high-order mode to the confinement loss of the fundamental mode. When HOMER is greater than 100, and the fundamental mode confinement loss is less than 0.1 dB / m, and the high-order mode confinement loss is greater than 1 dB / m, the optical fiber can be considered to be transmitting in single mode.

[0034] Figure 2 The horizontal axis represents the aperture size α of the anti-resonant element, in degrees (°), ranging from 0° to 180°. The left and right axes of the vertical axis represent confinement loss and HOMER (High-order mode extinction ratio), respectively. As α increases, the loss of the fundamental mode (LP01) remains essentially constant, while the loss of the higher-order mode (LP11) shows a trend of first increasing and then decreasing. HOMER reaches its peak at α = 100°, at 33634. Compared to α = 0° (when the anti-resonant element is a closed ring structure), HOMER = 4381, indicating that the open-ring structure significantly improves HOMER. Furthermore, it is demonstrated that using an arc-shaped open-ring structure can effectively improve the single-mode characteristics of optical fiber.

[0035] Figure 2 In this embodiment, the refractive index of the fiber core and cladding region is 1.444, and the refractive index of the first and second anti-resonant layers and the outer tube is 1.4378; the diameter of the fiber core is 60 μm, the diameter of the resonant unit in the first anti-resonant layer is 20 μm, the diameter of the resonant unit in the second anti-resonant layer is 46 μm, the spacing between the first and second anti-resonant layers is 1 μm, and the thickness of the anti-resonant element is 1 μm.

[0036] Figure 3 This is a schematic diagram illustrating the effect of fiber core diameter on single-mode properties, provided as an embodiment of the present invention. The fiber core diameter is a direct factor determining the effective mode area of ​​the fiber core. Figure 3The horizontal axis represents the core diameter d0 in μm, ranging from 60 μm to 184 μm. The left and right axes of the vertical axis represent confinement loss and higher-order mode rejection ratio (HOMER), respectively. With increasing core diameter, both fundamental and higher-order mode losses decrease, especially the confinement loss of higher-order modes, which decreases from 20 dB / m to 1.43 dB / m. This confirms that increasing core size leads to degradation of single-mode characteristics. Although the higher-order mode loss decreases to 1.43 dB / m, the HOMER remains above 1500, meaning the fiber still meets single-mode requirements. The maximum core diameter for single-mode transmission can reach 184 μm, corresponding to a mode field area of ​​15647 μm. 2 .

[0037] When the core diameter is 184 μm (mode area 15647 μm) 2 In this embodiment, the outer diameter is only 578 μm, which is significantly smaller than that of previously reported large mode area fibers, achieving diameters exceeding 10,000 μm. 2 When achieving ultra-large mode area, the outer diameter typically reaches the millimeter level. This embodiment achieves ultra-large mode area and single-mode transmission while effectively reducing the fiber outer diameter, which is of great significance for the miniaturization and integration of fiber lasers.

[0038] Figure 4 This diagram illustrates a structural alternative to an all-solid-state antiresonant optical fiber with an arc-shaped open ring structure, as provided in an embodiment of the present invention. The first antiresonant layer is a classic circular ring-shaped antiresonant unit, while only the second antiresonant layer uses an arc-shaped open antiresonant unit. Since the antiresonant units in the first antiresonant layer are relatively small, whether their structure is circular or arc-shaped only has a slight impact on loss limitation and does not degrade single-mode characteristics; the impact on the fiber's outer diameter is also negligible.

[0039] In summary, the existing circular anti-resonant unit structure maintains a maximum core diameter of 124 μm for single-mode transmission, corresponding to a mode field area of ​​7418 μm. 2 The present invention maintains a maximum core diameter of 184 μm for single-mode transmission, corresponding to a mode field area of ​​15647 μm. 2 .

[0040] The existing technology has a field area exceeding 10000μm. 2 Large mode area optical fibers typically have outer diameters on the order of millimeters, but the outer diameter of this invention is only 578 μm.

[0041] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0042] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for apparatus or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the description of the method embodiments. The apparatus and system embodiments described above are merely illustrative. 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 modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0043] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An all-solid-state anti-harmonic fiber having an arc-shaped open ring structure, characterized by, The application relates to an optical fiber structure, which comprises a fiber core (1), a first anti-resonance layer (2), a second anti-resonance layer (3), a cladding region (4) and an outer sleeve (5), wherein the fiber core (1) is circular, the first anti-resonance layer (2) surrounds the fiber core (1), and the second anti-resonance layer (3) surrounds the first anti-resonance layer (2); the anti-resonance elements in the first anti-resonance layer (2) and the second anti-resonance layer (3) are arranged in axial symmetry, the cladding region (4) is a matrix material region in the optical fiber structure except the fiber core (1), and the outer sleeve is an outer sleeve which wraps the optical fiber structure. The first anti-resonance layer (2) and the second anti-resonance layer (3) comprise anti-resonance elements with a plurality of arc-shaped openings; or the first anti-resonance layer (2) is a circular ring type anti-resonance unit, and the second anti-resonance layer (3) adopts an arc-shaped opening anti-resonance unit. The thickness and opening angle of the anti-resonance elements in the first anti-resonance layer (2) and the second anti-resonance layer (3) are the same, and the sizes are different.

2. The all-solid-state anti-resonant optical fiber according to claim 1, characterized in that, The fiber core (1) and the cladding region (4) are pure silica materials.

3. The all-solid-state anti-resonant optical fiber according to claim 1, wherein, The first anti-resonance layer (2), the second anti-resonance layer (3) and the outer sleeve (5) are high refractive index silica materials.

4. The all-solid-state anti-resonant optical fiber according to claim 1, wherein, The anti-resonance elements in the first anti-resonance layer (2) and the second anti-resonance layer (3) are not in contact with each other, and the distance between adjacent anti-resonance elements in the first anti-resonance layer (2) and the second anti-resonance layer (3) is 1-10 mu m.

5. The all-solid-state anti-resonant optical fiber according to claim 1, wherein, The opening size of the anti-resonance elements in the first anti-resonance layer (2) and the second anti-resonance layer (3) ranges from 0 to 180 degrees, and the thickness is 700-1700 nm.

6. The all-solid-state anti-resonant optical fiber according to claim 1, wherein, ​

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