Multi-layer hollow-core anti-resonance optical fiber

Abstract

The invention relates to a multi-layer hollow-core anti-resonant optical fiber. The anti-resonance hollow-core optical fiber comprises an outer cladding layer; a holding tube; a first plurality of cladding elements, the first plurality of cladding elements being disposed within the outer cladding; and a second plurality of cladding elements arranged in contact with the inner wall of the holding tube such that the second plurality of cladding elements defines a hollow core, where a first wall thickness of the second plurality of cladding elements causes a first anti-resonant state of the hollow core and a second wall thickness of the second plurality of cladding elements causes a second anti-resonant state of the hollow core. And the sum of the wall thickness of the holding tube and the wall thickness of the first plurality of cladding elements causes a second anti-resonant state of the hollow core.

Description

Cross-references to related applications

[0001] This patent application claims priority to U.S. Provisional Patent Application No. 63 / 719,539, filed November 12, 2024, entitled "HOLLOW-CORE ANTI-RESONANT FIBER," and U.S. Provisional Patent Application No. 63 / 748,808, filed January 23, 2025, entitled "HOLLOW-CORE ANTI-RESONANT FIBER." The disclosure of the earlier application is considered part of this patent application and is incorporated herein by reference. Technical Field

[0002] This disclosure generally relates to optical fibers and multilayer hollow-core antiresonant optical fibers. Background Technology

[0003] Hollow-core fiber (HCF) is a type of optical fiber designed to guide light through an air-filled, gas-filled, or vacuum core, rather than through a solid glass core used in some optical fibers. Unlike optical fibers with a solid glass core, HCF has a central hollow core typically surrounded by a microstructured cladding. HCF can be classified into different types based on its guiding mechanism. One type of HCF includes photonic bandgap fiber, which confines light by surrounding the hollow core with a periodic lattice of nodes. Another type of HCF (e.g., anti-resonant hollow-core fiber (AR-HCF)) includes anti-resonant fiber, which surrounds the core with a cladding of a specific thickness that is anti-resonant with the light guided by the core. The microstructured cladding of AR-HCF can consist of thin glass tubes or films arranged in a way that prevents light from escaping from the hollow core through a mechanism called anti-resonance. The microstructured cladding is designed to create an anti-resonance effect for certain wavelengths of light, effectively reflecting the light back into the hollow core. Therefore, the anti-resonance effect minimizes light leakage and improves transmission efficiency. AR-HCF can support a wide range of wavelengths, making it suitable for various applications, including telecommunications, sensing, and high-power laser transmission. Summary of the Invention

[0004] In some embodiments, the anti-resonant hollow fiber includes an outer cladding; a retaining tube; a first plurality of cladding elements disposed within the outer cladding; and a second plurality of cladding elements disposed in contact with the inner wall of the retaining tube such that the second plurality of cladding elements define a hollow core, wherein a first wall thickness of the second plurality of cladding elements causes a first anti-resonant state of the hollow core, and the sum of the wall thickness of the retaining tube and the wall thickness of the first plurality of cladding elements causes a second anti-resonant state of the hollow core.

[0005] In some embodiments, the antiresonant hollow fiber includes an outer cladding; a first layer disposed within the outer cladding and defining a first inner volume, wherein the first layer includes a first set of cladding elements; a second layer disposed within the first layer and defining a second inner volume, wherein the second layer includes a second set of cladding elements defining a hollow core; and a holding tube disposed between the first and second layers, wherein the arrangement of the first set of cladding elements, the second set of cladding elements, and the holding tube is associated with reducing fundamental mode loss. Fundamental mode loss is associated with the hollow core.

[0006] In some embodiments, the layered hollow fiber includes a first plurality of cladding elements disposed in a first internal volume; a second plurality of cladding elements disposed in a second internal volume; and a retaining tube disposed between the first internal volume and the second internal volume, wherein the second plurality of cladding elements define the hollow core, and wherein the respective wall thicknesses of the first plurality of cladding elements, the second plurality of cladding elements, and the retaining tube are configured to induce an anti-resonant state in the hollow core. Attached Figure Description

[0007] Figure 1 A diagram of an example optical fiber (such as a multilayer hollow anti-resonant fiber).

[0008] Figure 2 A diagram relating to an example optical fiber (such as a set of components associated with a multilayer hollow antiresonant fiber).

[0009] Figure 3A and 3B This is a diagram showing the formation of a hollow core (such as that used in hollow anti-resonant optical fibers).

[0010] Figure 4 A flowchart illustrating an example process associated with the fabrication of multilayer hollow antiresonant optical fibers. Detailed Implementation

[0011] The exemplary embodiments are described in detail below with reference to the accompanying drawings. The same reference numerals in different drawings may identify the same or similar elements.

[0012] Hollow-core antiresonant fiber (which may be referred to as "HC-ARF" or "AR-HCF") can be used to propagate light through a core surrounded by a microstructured cladding (e.g., an air-filled core, a gas-filled core, or a vacuum core). For example, HC-ARF may include a set of cladding elements arranged in a ring configuration around a hollow core through which light can propagate. This set of cladding elements, which may also be referred to as "capillaries," "walls," or "capillary walls," uses antiresonant reflection to confine the light within the hollow core. Compared to other types of fiber, using HC-ARF can provide lower loss, reduce nonlinear effects, and enable higher power capacity. Therefore, HC-ARF can be used in telecommunications to support low-latency data transmission and high-capacity networks. Additionally or alternatively, HC-ARF can be used in high-power laser systems, such as for industrial laser processing (e.g., cutting or welding) or medical applications (e.g., laser surgery or dermatological surgery), by providing precise and efficient transmission of a high-power laser beam with minimal loss or beam distortion.

[0013] Furthermore, HC-ARF can support ultrafast pulse transmission, such as femtosecond and picosecond laser pulses with minimal dispersion, enabling use cases for other applications such as spectroscopy, imaging, or the generation of supercontinuum spectra. In some sensing applications, HC-ARF can have a gas-filled core instead of an air-filled hollow core, which allows for extended interaction lengths, thereby improving sensor sensitivity. Other HC-ARFs can have a vacuum-filled core, which can introduce additional properties. Some HC-ARFs can support nonlinear optical processes, such as Raman scattering or four-wave mixing, providing improved light source or detection capabilities in applications such as environmental monitoring.

[0014] Optimization techniques can be used to configure the arrangement and size of the cladding elements surrounding the hollow core of an HC-ARF, thereby enabling the configuration of a specific set of characteristics of the HC-ARF. However, the HC-ARF may be affected by fundamental mode (FM) loss. For example, when individual cladding elements are separated by excessively large gaps, the HC-ARF may experience excessive leakage in the region between the cladding elements defining the hollow core of the HC-ARF. Similarly, the HC-ARF may experience loss when light can form junctions where individual cladding elements are not sufficiently separated by gaps.

[0015] Some embodiments described herein provide a multilayer HC-ARF. For example, an HC-ARF may include a set of outer cladding elements in a first annular configuration and a set of inner cladding elements in a second annular configuration offset from the first annular configuration. In this case, the configuration of the cladding elements (such as the location of the cladding elements and the wall thickness of the cladding elements (and the retainer wall thickness of the retainer tube)) can reduce FM loss caused by the HC-ARF. In some embodiments, the HC-ARF may include a retainer tube supporting the inner cladding elements, or an outer cladding layer surrounding the outer cladding elements. In this way, by providing multiple cladding elements, the sum of the wall thickness of the outer cladding elements and the retainer wall thickness of the retainer tube results in reflection of light escaping from the hollow core defined by the inner cladding elements (and through the gaps between the inner cladding elements), thereby reducing FM loss. For example, an HC-ARF can achieve a fundamental mode loss limitation of less than 1 dB / km.

[0016] Figure 1 This is a diagram of an example optical fiber 100 (such as a multilayer hollow antiresonant fiber). The optical fiber 100 may include an outer cladding 105, an outer cladding layer 110, a retaining tube 115, and an inner cladding layer 120. A first set of cladding elements 125 may be disposed in a first internal volume corresponding to the outer cladding layer 110. A second set of cladding elements 130 may be disposed in a second internal volume corresponding to the inner cladding layer 120. The second set of cladding elements 130 may define a hollow region 135 capable of transmitting a light beam or optical signal.

[0017] In some embodiments, the outer cladding layer 110 may have an outer wall and an inner wall defining a first internal volume, in which the first set of cladding elements 125 are disposed. For example, the first set of cladding elements 125 may be disposed between the first inner wall and the first outer wall of the outer cladding layer 110. In some embodiments, the outer cladding layer 110 may be an empty layer. For example, the outer cladding layer 105 may form an outer boundary or outer wall, and the retaining tube 115 may form an inner boundary or inner wall, these boundaries or walls defining the space of the outer cladding layer 110 in which the first set of cladding elements 125 are disposed. In this case, the empty layer of the outer cladding layer 110 may be a vacuum medium, or may include a gaseous medium (such as air or a liquid medium).

[0018] Alternatively, the outer cladding layer 110 may be a material layer. In some embodiments, the outer cladding layer 110 is associated with a specific filler material. For example, the outer cladding layer 110 may have a material (such as doped quartz glass) disposed between the first set of cladding elements 125. Although some embodiments are described herein in terms of a specific set of material types or phases, other material types or phases are also contemplated. Additionally, although some layers are described herein in terms of a single material or a single monolayer, it is contemplated that individual layers described herein may comprise multiple materials or multiple layers. It is contemplated that different material or structural configurations may have different manufacturing processes.

[0019] In some embodiments, the outer cladding 105 and the outer cladding layer 110 may be formed of a single type of material. For example, the outer cladding 105 and the outer cladding layer 110 disposed between the first set of cladding elements 125 may be made of the same material. In this case, the outer cladding layer 110 and the outer cladding 105 may be a single continuous layer (in which the first set of cladding elements 125 are disposed (e.g., via drilling)) rather than forming a wall between the outer cladding layer 110 and the outer cladding 105.

[0020] Alternatively, the outer cladding 105 can be a different layer in contact with the outer wall of the outer cladding layer 110. For example, the outer cladding 105 can be a first material, the outer cladding layer 110 can be a second material, and the retaining tube 115 can be a third material. In this case, the first set of cladding elements 125 is disposed within the second material. Alternatively, the outer cladding layer 110 and the retaining tube 115 can be the same material. In this case, the outer cladding layer 110 and the retaining tube 115 can be a single continuous layer (in which the first set of cladding elements 125 is disposed (e.g., via a drilled hole)), rather than forming a wall between the outer cladding layer 110 and the retaining tube 115.

[0021] In some embodiments, the retaining tube 115 may include an outer wall and an inner wall. For example, the inner wall of the retaining tube 115 may be formed within a second internal volume corresponding to the inner cladding layer 120 to support a second set of cladding elements 130. In this case, the second set of cladding elements 130 may contact the inner wall of the retaining tube 115. In some embodiments, the retaining tube 115 may have a retaining tube wall thickness that, along with other wall thicknesses (e.g., along with the wall thickness of the cladding element 125), is associated with an anti-resonance state. For example, the retaining tube wall thickness of the retaining tube 115 may be configured such that, together with the wall thickness of the cladding element 125, it minimizes the FM loss of light within the hollow region 135 by satisfying an anti-resonance state. Reference numeral 150 indicates the corresponding thickness of some components described herein. For example, the cladding element 125 has a wall thickness 125a, which is the distance between the outer wall and the inner wall of the cladding element 125. Similarly, cladding element 130 has a wall thickness of 130a, which is the distance between the outer wall and the inner wall of cladding element 130. Holding tube 115 has a holding tube wall thickness of 115a, which is the distance between the outer wall and the inner wall of holding tube 115. As described in more detail herein, wall thickness 130a satisfies an anti-resonant state associated with reducing FM loss of light. Similarly, the total thickness 152 (which is the sum of wall thickness 125a and holding tube wall thickness 115a) satisfies an anti-resonant state associated with reducing FM loss of light.

[0022] Initially, the interior of the retaining tube 115 may be an empty volume, into which a second set of cladding elements 130 are attached to define an inner cladding layer 120 and a hollow region 135. In some embodiments, the gaps between the hollow region 135 or the cladding elements 130 may be filled with air, another gas, or a vacuum. In some embodiments, the retaining tube 115 may be made of a material such as the cladding material.

[0023] In some embodiments, the second set of cladding elements 130 may define a hollow region 135, which may or may otherwise include a light-guiding region and / or a light-confining region. For example, the first set of cladding elements 125 and the second set of cladding elements 130 may confine and guide light within the hollow region 135. The hollow region 135 may be associated with a negative surface of the second set of cladding elements 130. In other words, although shown as a circular hollow region 135, the hollow region 135 extends along the contour of the outer wall of the cladding element 130 (e.g., a portion of the outer wall facing inward toward the center of the circular hollow region 135), which serves as the boundary of the hollow region 135. The gaps between the cladding elements 130 may form openings in the boundary of the hollow region 135, which results in losses; however, as described herein, the presence of the first set of cladding elements 125 as an additional confining layer results in the openings in the boundary of the hollow region 135 being closed (or smaller than the openings produced by a single-layer HC-ARF). Therefore, the first set of cladding elements 125 and the second set of cladding elements 130 can be tubes configured to guide light based on the anti-resonance effect generated by the combination of the wall thickness 125a of the first set of cladding elements 125 and the retaining tube wall thickness 115a of the retaining tube 115 (e.g., total thickness 152) and the anti-resonance effect generated by the wall thickness 130a of the second set of cladding elements 130.

[0024] In some embodiments, the first set of cladding elements 125 and the second set of cladding elements 130 may be associated with a specific cross-sectional shape. For example, the first set of cladding elements 125 and the second set of cladding elements 130 may be configured with a circular cross-section to enhance the anti-resonance state, through which the first set of cladding elements 125 and the second set of cladding elements 130 guide light in the hollow region 135 to reduce loss. In some embodiments, the first set of cladding elements 125 and the second set of cladding elements 130 may be associated with a tube material (such as pure quartz glass) that is different from the material of the cladding layers (such as the outer cladding layer 110 or the retaining tube 115).

[0025] In some embodiments, the first set of cladding elements 125 and the second set of cladding elements 130 may each be associated with a corresponding annular configuration. For example, the first set of cladding elements 125 may be arranged in a first annular configuration within the outer cladding layer 110, and the second set of cladding elements 130 may be arranged in a second annular configuration within the inner cladding layer 120 (e.g., against the inner wall of the retaining tube 115). In some embodiments, the corresponding annular configurations may be offset. For example, the first annular configuration may be rotatably offset from the second annular configuration, such that the gaps between adjacent cladding elements of the first set of cladding elements 125 and the second set of cladding elements 130 are aligned. In some embodiments, one or more cladding elements 125 or 130 may be configured to transmit a light beam or optical signal.

[0026] In some embodiments, the cladding elements of optical fiber 100 (e.g., cladding elements 125 and 130) may be associated with a uniform distribution. For example, a first ring configuration may include a first set of cladding elements 125 offset by 60 degrees (°) to positions corresponding to the 12, 2, 4, 6, 8, and 10 o'clock, and a second ring configuration may include a second set of cladding elements 130 at positions 1, 3, 5, 7, 9, and 11 o'clock. Additionally or alternatively, the cladding elements of optical fiber 100 may be associated with a non-uniform distribution. For example, instead of six cladding elements with a 60° offset, a single layer of cladding elements (such as cladding element 125) may have adjacent cladding elements with other offset angles. In this case, the first pair of cladding elements 125 or 130 may be offset by a first angular distance (e.g., 60°), but the second pair of cladding elements 125 or 130 may be offset by a second angular distance (e.g., 50° or another angle). In some implementations, each cladding element 125 and each cladding element 130 is associated with an offset angle sufficient to ensure that no cladding element contacts an adjacent cladding element. In other words, the offset angle can be selected based on the size and number of cladding elements within the cladding layer to ensure a gap exists between adjacent cladding elements. While having a gap between adjacent cladding elements can be advantageous, in some configurations, for example, as a result of the manufacturing process or to achieve specific effects on the hollow region 135 and the light guided therein, one or more pairs of adjacent cladding elements may contact each other.

[0027] In some embodiments, a specific number of cladding elements may be provided in the optical fiber 100. For example, the outer cladding layer 110 may include a set of six cladding elements 125, and the inner cladding layer 120 may include a set of six cladding elements 130. Additionally or alternatively, the outer cladding layer 110 and the inner cladding layer 120 may have other numbers of cladding elements, such as seven, eight, nine, ten, or more cladding elements per cladding layer. In other configurations, fewer cladding elements may be included in the cladding layers. Additionally or alternatively, the outer cladding layer 110 may have a different number of cladding elements than the inner cladding layer 120. For example, the inner cladding layer 120 may include a first number of cladding elements 130, and the outer cladding layer 110 may include a second (different) number of cladding elements 125.

[0028] In some embodiments, cladding elements of a specific thickness may be provided in the optical fiber 100. For example, the outer cladding layer 110 may include a set of cladding elements 125 having a specific wall thickness, and the inner cladding layer 120 may include a set of cladding elements 130 having the same specific wall thickness. The wall thickness is related to the wavelength used and may be a combination of the specific wall thickness of the cladding element 130 or the specific wall thickness of the cladding element 125 with the retainer wall thickness of the retainer tube 115, and may be as high as a few micrometers (e.g., about 2 micrometers) or about a few hundred nanometers (e.g., about 700 nanometers). In some embodiments, the outer cladding layer 110 may have a different cladding element wall thickness than the inner cladding layer 120. For example, the inner cladding layer 120 may include cladding elements 130 with a first wall thickness, and the outer cladding layer 110 may include cladding elements 125 with a second (different) wall thickness. Additionally or alternatively, the different cladding elements within a cladding layer may have different wall thicknesses. For example, the first cladding element 125 may have a first wall thickness, and the second cladding element 125 may have a second (different) wall thickness. In this case, by having different cladding element wall thicknesses within a single cladding element, the optical fiber 100 can induce birefringence, which can be used in some applications, such as for polarization-maintaining fibers.

[0029] In some embodiments, the anti-resonant state of the optical fiber 100 and its hollow core region 135 can be associated with the wall thickness of the cladding element 125 (e.g., in combination with the retaining tube 115) or the cladding element 130. For example, as described in more detail herein, the wall thickness of the cladding element 130 or 125 (e.g., in combination with the retaining tube wall thickness of the retaining tube 115) can be configured to produce constructive interference between light reflected from the outer wall boundary into the core and light that penetrates into the wall and is then reflected from the inner wall boundary into the core. The value of the wall thickness at which light is reflected back to the hollow core region 135 as constructive interference can be referred to as the "anti-resonant thickness". The anti-resonant thickness can be approximated using the following equation: in t For anti-resonance thickness, m The order of the resonant band. λ In order to constrain the wavelength of light in the hollow region 135, n 1 represents the refractive index of the cladding element 125 or 130, and n0 represents the refractive index of the hollow region 135 (e.g., the refractive index of the air or another gas filling the hollow region 135). Therefore, using such a numerical approximation, the anti-resonance thickness can be determined as an approximation or used in numerical simulations. In some embodiments, for a multilayer arrangement including cladding element 125, cladding element 130, and a retaining tube 115 therebetween, the anti-resonance thickness can be the wall thickness of cladding element 130 or the sum of the wall thickness of cladding element 125 and the retaining tube wall thickness of retaining tube 115. In one example, for a wavelength of 1030 nm, a thickness ranging from 0.73 micrometers (µm) to 0.79 µm can be selected as the anti-resonant thickness for that wavelength. This could result in the wall thickness of a set of cladding elements 130 being selected to be 0.76 µm, the wall thickness of a set of cladding elements 125 being selected to be 0.38 µm, and the wall thickness of the retainer tube 115 being selected to be 0.38 µm (e.g., resulting in a combined thickness of 0.76 µm for the cladding elements 125 and the retainer tube 115). Additionally or alternatively, the wall thickness and arrangement of the cladding elements 125 or 130 and the retainer tube 115 can be selected to ensure that the base mold has minimal potential losses (e.g., the amount of light escaping from the hollow region 135).

[0030] As indicated above, provide Figure 1 As an example. Other examples can be related to... Figure 1 The descriptions are different.

[0031] Figure 2 This is a diagram of an example implementation 200 for the production of optical devices (such as multilayer hollow anti-resonant optical fibers) and the stacks associated therewith.

[0032] like Figure 2 As shown, Example Embodiment 200 may include a blank 210 comprising a set of inner cladding elements attached to a retaining tube. Example Embodiment 200 may include a stack 220 comprising a set of outer cladding elements disposed within a cladding layer or outer cladding. As indicated by reference numeral 230, the blank 210 may be disposed within the stack 220 such that the set of inner cladding elements forms a hollow core, and the set of inner cladding elements and the set of outer cladding elements (attached to the retaining tube) together provide an anti-resonant state for the hollow core. Based on inserting the blank 210 into the stack 220, the blank 210 and the stack 220 may be drawn together and inserted into a sleeve to form an assembly. The assembly of the blank 210, the stack 220, and the sleeve may be drawn into an optical fiber.

[0033] As indicated above, provide Figure 2 As an example. Other examples can be related to... Figure 2 The descriptions are different.

[0034] Figure 3A and Figure 3BA diagram illustrating the formation of a hollow core, such as that used in hollow-core anti-resonant optical fibers.

[0035] like Figure 3A As shown, in a single-layer hollow antiresonant fiber, different diameters of the single-layer cladding elements can lead to different characteristics of the hollow core formed therein. For example, a first fiber 310 includes a cladding element with a first diameter, a second fiber 320 includes a cladding element with a second diameter, and a third fiber 330 includes a cladding element with a third diameter. The first diameter, being the largest of the three diameters, results in the formation of glass junctions (e.g., contact between adjacent cladding elements), which leads to losses in the fundamental mode guided through the hollow core. Conversely, the third diameter, the smallest of the three diameters, allows for excessive FM losses through the gaps between the cladding elements. The second diameter represents an optimization between avoiding FM losses and avoiding junction formation, thus optimizing performance. However, as... Figure 3B As shown, by adding a second layer, the performance of multilayer hollow antiresonant fibers can be further improved. For example, in Figure 3B In the optical fiber 340, there are inner cladding elements having a second diameter and outer cladding elements having a fourth diameter aligned with the gap between the inner cladding elements. The inner cladding elements do not contact each other (e.g., do not form a junction), and the presence of the outer cladding elements provides additional anti-resonance, which confines the fundamental mode, thereby enabling the reflection of light (in conjunction with the retainer tube), which would otherwise allow light to escape between the inner cladding elements and return to the core.

[0036] As indicated above, provide Figure 3A and 3B As an example. Other examples can be related to... Figure 3A and 3B The descriptions are different.

[0037] Figure 4 This is a flowchart of an example process 400 associated with the manufacture of multilayer hollow antiresonant optical fibers. Figure 4 One or more process blocks are executed by the manufacturing equipment.

[0038] like Figure 4 As shown, process 400 includes providing a retaining tube (block 410) having a plurality of cladding elements. For example, as described above, the manufacturing equipment can provide a retaining tube having a first plurality of cladding elements formed in the retaining tube. In some embodiments, the manufacturing equipment can draw a set of capillaries and insert the set of capillaries into the retaining tube. The manufacturing equipment can draw the retaining tube and the set of capillaries into a billet 210. The manufacturing equipment can provide a billet 210 having a plurality of cladding elements as a retaining tube.

[0039] like Figure 4As further shown, process 400 includes providing an outer cladding tube (block 420) having a plurality of cladding elements. For example, as described above, the manufacturing apparatus may form an outer cladding tube having a second plurality of cladding elements formed within the outer cladding tube. In some embodiments, the manufacturing apparatus may form a stack 220 including a second plurality of cladding elements on the exterior of a retaining tube. The manufacturing apparatus may provide a stack 220 having a plurality of cladding elements as an outer cladding tube.

[0040] like Figure 4 As further shown, process 400 includes inserting a retaining tube into an outer cladding tube and drawing (block 430). For example, as described above, the manufacturing apparatus may insert a blank 210, which includes multiple cladding elements (formed in a blank 210), into an opening of a stack 220, which includes another multiple cladding elements (formed in an opening of a stack 220), thereby defining a hollow core of the optical fiber. In other words, the manufacturing apparatus may insert a retaining tube having multiple capillary elements into an outer cladding tube having multiple capillary elements to create two layers of capillary elements. In some embodiments, the manufacturing apparatus may draw a combined assembly.

[0041] like Figure 4 As further shown, process 400 includes insertion into a sleeve and drawing (block 440). For example, as described above, the manufacturing equipment can insert a blank 210 and a stack 220 (e.g., formed by drawing a retaining tube, an outer cladding tube, and a combination of multiple cladding elements) into a sleeve to form a combined assembly, and can draw the combined assembly to form an optical fiber.

[0042] Process 400 may include additional aspects, such as any single aspect or any combination of aspects described herein and / or aspects related to one or more other processes described elsewhere herein.

[0043] although Figure 4 An example block of process 400 is shown, but in some embodiments, process 400 includes more than Figure 4 The blocks depicted may be more blocks, fewer blocks, different blocks, or blocks with different arrangements. Additionally or alternatively, two or more blocks of process 400 may be executed in parallel.

[0044] The foregoing disclosure provides illustrations and descriptions, but is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. Modifications and variations can be made based on the foregoing disclosure or can be obtained from practice with the embodiments. Furthermore, any of the embodiments described herein can be combined unless the foregoing disclosure expressly provides a reason why one or more embodiments cannot be combined.

[0045] As used in this article, depending on the context, "meeting the threshold" can refer to a value that is greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, etc.

[0046] Despite the specific combinations of features listed in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various embodiments. In fact, many of these features can be combined in ways not specifically listed in the claims and / or not specifically disclosed in the specification. While each dependent claim listed below may be directly subordinated to only one claim, the disclosure of various embodiments includes combinations of each dependent claim with each other claim in the claim set. As used herein, the phrase “at least one of” in the list of items refers to any combination of those items, including a single member. For example, “at least one of a, b, or c” is intended to cover a, b, c, ab, ac, bc, and abc, as well as any combination with multiple identical items.

[0047] Unless explicitly stated otherwise, no element, action, or instruction used herein should be construed as essential or necessary. Furthermore, as used herein, the articles “a” and “an” are intended to include one or more items and are interchangeable with “one or more.” Furthermore, as used herein, the article “the” is intended to include one or more cited items in relation to the article “the” and is interchangeable with “one or more.” Furthermore, as used herein, the term “set” is intended to include one or more items (e.g., related items, unrelated items, or a combination of related and unrelated items) and is interchangeable with “one or more.” If intended to indicate only one item, the phrase “only one” or similar language is used. Furthermore, as used herein, the terms “has,” “have,” “having,” etc., are intended to be open-ended terms. Furthermore, the phrase “based on” is intended to mean “based, at least in part, on,” unless explicitly stated otherwise. Furthermore, as used herein, the term “or” is intended to be inclusive when used in a series and may be used interchangeably with “and / or” unless otherwise explicitly stated (e.g., if used in conjunction with “either” or “only one of”). Additionally, for ease of description, spatially relative terms such as “below,” “lower,” “above,” “upper,” etc., may be used herein to describe the relationship of one element or feature to another element or feature illustrated in the figures. Spatially relative terms are intended to cover different orientations of devices, apparatuses, and / or elements in use or operation, in addition to the orientations depicted in the figures. Devices may be oriented in other ways (rotated 90 degrees or other orientations), and the spatially relative descriptors used herein may be interpreted accordingly.

Claims

1. An anti-resonant hollow-core optical fiber, comprising: Outer layer; Retaining tube; A plurality of cladding elements are arranged within the outer cladding; as well as A second plurality of cladding elements are arranged to contact the inner wall of the retaining tube, such that the second plurality of cladding elements define a hollow core. The first wall thickness of the second plurality of cladding elements causes the first anti-resonance state of the hollow core, and the sum of the tube wall thickness and the wall thickness of the first plurality of cladding elements causes the second anti-resonance state of the hollow core.

2. The anti-resonant hollow optical fiber according to claim 1, wherein the cladding elements of the first plurality of cladding elements and the second plurality of cladding elements are separated by gaps such that no cladding element contacts another cladding element.

3. The anti-resonant hollow optical fiber according to claim 1, wherein the first plurality of cladding elements are rotatably offset from the second plurality of cladding elements, such that the gaps between the first plurality of cladding elements and the cladding elements of the second plurality of cladding elements are aligned.

4. The anti-resonant hollow fiber of claim 1, wherein the first anti-resonant state and the second anti-resonant state are associated with the corresponding wall thicknesses of the first plurality of cladding elements, the second plurality of cladding elements and the retaining tube, the retaining tube being configured to reflect light from the hollow core back into the hollow core such that there is constructive interference between light reflected from the outer wall boundary into the core and light penetrating into the outer wall and then reflected from the inner wall boundary into the core.

5. The anti-resonant hollow optical fiber according to claim 1, wherein the first anti-resonant state and the second anti-resonant state are associated with the wavelength of light in the hollow core.

6. The anti-resonant hollow fiber according to claim 1, wherein the first pair of cladding elements in the second plurality of cladding elements is associated with a first angular distance, and the second pair of cladding elements in the second plurality of cladding elements is associated with a second angular distance.

7. An anti-resonant hollow optical fiber, comprising: outer cladding; The first layer is disposed within the outer cladding and defines a first internal volume. The first layer includes a first group of cladding elements; The second layer is disposed within the first layer and defines a second internal volume. The second layer includes a second set of cladding elements. The second set of cladding elements defines the hollow core; and A retaining tube is disposed between the first layer and the second layer. The configuration of the first set of cladding elements, the second set of cladding elements, and the retaining tube is associated with reducing the loss of the fundamental mold, which in turn is associated with the hollow core.

8. The anti-resonant hollow fiber of claim 7, wherein the first set of cladding elements is associated with a first ring structure, and the second set of cladding elements is associated with a second ring structure.

9. The anti-resonant hollow fiber of claim 8, wherein the first annular structure and the second annular structure are configured with gaps between cladding elements such that no cladding element in the first group of cladding elements or the second group of cladding elements contacts any other cladding element in the first group of cladding elements or the second group of cladding elements.

10. The anti-resonant hollow fiber according to claim 8, wherein the first annular structure is offset from the second annular structure such that the gaps between the first set of cladding elements and the second set of cladding elements are aligned.

11. The anti-resonant hollow fiber of claim 7, wherein the first cladding element in the second set of cladding elements is associated with a first thickness, and the second cladding element in the second set of cladding elements is associated with a second thickness, such that the birefringence state is configured relative to the hollow core.

12. The anti-resonant hollow fiber according to claim 7, wherein the first set of cladding elements comprises two or more cladding elements.

13. The anti-resonant hollow fiber according to claim 7, wherein the second set of cladding elements comprises two or more cladding elements.

14. The anti-resonant hollow fiber according to claim 7, wherein the simulated limiting loss of the fundamental mode is less than 1 dB / km.

15. The anti-resonant hollow optical fiber according to claim 7, wherein the outer cladding is a sleeve.

16. A layered hollow optical fiber, comprising: A plurality of cladding elements are disposed within a first internal volume; The second plurality of cladding elements are disposed in the second internal volume; as well as A retaining tube is disposed between the first internal volume and the second internal volume. The second plurality of cladding elements define the hollow core, and The wall thicknesses of the first plurality of cladding elements, the second plurality of cladding elements, and the retaining tube are configured to induce an anti-resonance state in the hollow core.

17. The layered hollow optical fiber according to claim 16, comprising: An outer cladding layer surrounds the first plurality of cladding elements.

18. The layered hollow optical fiber according to claim 16, comprising: The filler material is disposed between the first cladding element of the first plurality of cladding elements or the second cladding element of the second plurality of cladding elements.

19. The layered hollow optical fiber according to claim 16, wherein the adjacent cladding elements of the first plurality of cladding elements and the second plurality of cladding elements do not contact each other.

20. The layered hollow optical fiber of claim 16, wherein the anti-resonance state is associated with the wavelength of light in the hollow core.

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