Lateral Anderson localized optical waveguide with reduced bending, thermal expansion equalization

Abstract

The invention relates to a lateral Anderson localized optical waveguide with reduced bending, thermal expansion equalization. The optical waveguide consists of a fiber bundle comprising at least two different structural elements. The low curvature of the waveguide is achieved by a net CTE modulus near zero by rearranging some of the structural elements of the fiber bundle to different quadrants of the waveguide cross-section.

Description

Technical Field

[0001] The present invention relates to a lateral Anderson localized optical waveguide with reduced bending and balanced thermal expansion for transmitting electromagnetic waves, especially for transmitting image information, and a method for manufacturing a waveguide, especially an image guide. Background Art

[0002] The image conductor is usually composed of a plurality of individual optical fibers, each of which consists of a core and a cladding surrounding the core, the optical fibers are assembled into bundles, and their cross sections are arranged in a grid with a one-to-one relationship between the light incident face and the light exit face to form a plurality of pixels. Basically, each pixel is used to transmit a brightness value or color information through the image conductor.

[0003] In practice, it is usually desirable to have the highest possible resolution for the image conductor. In principle, high resolution can be achieved by reducing the diameter of the individual waveguides. However, due to physical laws, the resolution cannot be increased linearly, because as the diameter of the individual waveguides continues to decrease, the increasing part of the field distribution of the transmission mode exceeds the size of the waveguides (especially the cladding), which leads to increased crosstalk between adjacent waveguides, resulting in increased image blur.

[0004] One approach to providing image conductors with higher resolution is based on the wave phenomenon of Transverse Anderson Localization (TAL). This exploits the fact that the random distribution of the refractive index in the cross section of the image conductor and the fact that the refractive index of each optical fiber remains constant along the length of the image conductor results in a confined coupling of light within the cross section due to destructive interference. In practice, for example, a plurality of individual optical fibers with different refractive indices can be combined to form a Transverse Anderson Localized Light waveguide. If a light beam is coupled into such a waveguide, it will propagate along the length of the waveguide, with its lateral extension limited to that in the cross section.

[0005] On the one hand, image conductors based on the principle of lateral Anderson localization enable higher resolutions, on the other hand, the random distribution of the refractive index may lead to the disadvantage that the image quality of the transmitted image information, in particular the image sharpness, may be affected by local fluctuations or may be difficult to control. For example, the image sharpness in certain areas of a cross section may differ from the image sharpness in other areas of the cross section.

[0006] This inhomogeneity makes it difficult in practice to manufacture image conductors with a certain quality standard. Depending on the quality standard adopted in production, a large number of substandard products may appear. The above-mentioned problem is further aggravated when the cross-sectional area of ​​the image conductor should have larger dimensions. This applies in particular to panels whose side length or cross-sectional diameter sometimes exceeds the thickness of the panel by several times.

[0007] Furthermore, the disorder required to ensure high optical performance of the image conductor may have an impact on other physical properties of the waveguide. For example, after stretching during the fiber drawing process or even after the fiber bundle is produced, bent fibers are often present in the waveguide. This can lead to problems such as:

[0008] 1) Curvature degrades the optical properties of the waveguide. In particular, it increases the noise level in the transmitted signal, thus reducing signal quality and image quality;

[0009] 2) the fiber may be more susceptible to mechanical failure due to sustained tensile stress on one of its edges; and

[0010] 3) Optical fibers can be difficult to handle and not strong enough, and it is not always possible to align bent fibers into a fiber bundle.

[0011] A panel is a type of waveguide, which is generally understood as a set of often relatively short (a few millimeters), fused optical fibers whose axes are perpendicular to the panel surface with a cross-sectional area of ​​a few square millimeters to several square centimeters. The core property of a panel is the ability to achieve image transmission from one surface of the panel to its opposite surface, which image transmission remains consistent in a strict order, i.e. 1:1, or according to a regular variation, such as rotation. Summary of the invention

[0012] The object of the present invention is therefore to provide a waveguide, in particular an image conductor, and a method for producing the same, in which a higher uniformity is achieved in the cross section of the waveguide, in particular to increase the image sharpness. One aspect of the task of the present invention is to make the uniformity in the cross section more controllable and reproducible, for example in order to be able to avoid rejects in the production process and to be able to consistently produce waveguides that meet certain quality standards. Another aspect of the present invention is to reduce the degree of bending.

[0013] One aspect of the object of the present invention is to be able to provide a waveguide, in particular a picture conductor, with a large cross-sectional area by means of Anderson localization, which waveguide simultaneously satisfies the aforementioned conditions, in particular a defined homogeneity. This relates in particular to a waveguide designed as a panel.

[0014] The present invention discloses a waveguide for transmitting electromagnetic waves using Anderson localization, in particular, transmitting image information from the proximal end of the waveguide to the distal end of the waveguide along a transmission direction extending between the proximal end and the distal end, wherein the waveguide comprises: a fiber bundle, the fiber bundle extends along the transmission direction and comprises a first structural element and a second structural element different from the first structural element. In some embodiments, regardless of whether they have different cross-sectional areas, the refractive indexes of the first structural element and the second structural element are different. The bending radius of the fiber bundle (also referred to as "curvature" in this article) can be 0.1m -1 Below, the net CTE modulus (Net CTE Modulus) is 0.01 ppm / K or less.

[0015] At least two different types of structural elements can be used, namely a first type having a first refractive index and a second type having a second refractive index different from the first refractive index. Therefore, the plurality of structural elements may include at least one structural element of the first type and at least one structural element of the second type. Of course, more than two different types of structural elements may also be used, for example, three different types of structural elements.

[0016] The structural elements each extend along the transport direction and the cross section of the waveguide in such a way that a plurality of cross-sectional areas are defined in the cross section of the waveguide, each of the cross-sectional areas corresponding to the cross section of an individual structural element. Thus, the structural elements may extend side by side, in particular parallel to each other, along the transport direction of the waveguide, and their cross sections each occupy a plane portion of the cross section of the waveguide and thereby each define a cross-sectional area of ​​the cross section of the waveguide. Thus, when observing a cross section of the waveguide (e.g. a light entry face or a light exit face), the cross-sectional area may specifically correspond to a surface area formed by the structural elements.

[0017] According to some embodiments of the invention, the first structural element differs from the second structural element in terms of their refractive index, cross-sectional area and / or composition.

[0018] In some embodiments, during the fabrication of the waveguide, the physical arrangement of each structural element relative to other structural elements is mathematically determined so that the net CTE modulus of the fiber bundle is less than 0.01 ppm / K.

[0019] The cross-sectional areas of the structural elements may have mutually inconsistent geometries, such as inconsistent diameters. However, the geometries of the cross-sectional areas may also be of the same type. In addition, a waveguide consisting of a plurality of fiber bundles fused together may be twisted (e.g., inverted) about a central axis of the waveguide to form an inverted waveguide, such as the non-limiting example disclosed in U.S. Pat. No. 11,079,538, the entire contents of which are hereby incorporated by reference into this application.

[0020] In some embodiments, each fiber has a diameter, and the diameter of the fibers varies as the fibers are radially displaced from the central axis of the bundle, such as the non-limiting example disclosed in US Pat. No. 11,079,538, the entire contents of which are hereby incorporated by reference into this application.

[0021] The structural element may be arranged so that the electromagnetic waves transmitted by the waveguide remain localized in a direction extending transversely to the transport direction, while reducing bending of the fibers during fiber drawing. Bending refers to the bending of the fiber bundle along its length. In particular, the curvature increases the noise level in the transmitted signal and reduces signal quality and image quality. In addition, since one side of the structural element is in a state of continuous tensile stress, the curvature makes the structural element more susceptible to mechanical failure. The curvature also makes the structural element difficult to handle and difficult to incorporate into a structural element bundle.

[0022] The structural elements are arranged in a mathematical manner such that the waveguide has a repeatable structure, in particular such that further waveguides having the same or substantially similar structure as the waveguide can be produced.

[0023] One method of producing a fiber bundle with minimal bending and other advantages is to arrange the first structural element and the second structural element during the manufacturing process of the fiber bundle so that the net CTE modulus of a fiber bundle is less than 0.01 ppm / K. This value is calculated mathematically as described herein. A single fiber bundle having a net CTE modulus within this range is considered to be "balanced" in terms of CTE, and because such a single bundle is balanced, a waveguide formed by fusing many such balanced fiber bundles will itself be balanced.

[0024] The ratio of the total area of ​​the cross-sectional area of ​​the first structural element to the total area of ​​the cross-sectional area of ​​the second structural element can be, for example, in the range of 1:150 to 150:1, 1:100 to 100:1, 1:50 to 50:1, 1:10 to 10:1, 3:7 to 7:3, 4:6 to 6:4, or 5:5. This can also be understood as a filling degree.

[0025] The refractive index of the first structural element and the refractive index of the second structural element differ by at least 10-4 , for example at least 10 -3 , for example at least 10 -2 , for example at least 10 -1 , such as at least 1, such as at least 2, such as at least 3, such as at least 4.

[0026] For the lateral extension of the structural elements, a minimum lateral dimension of at least one cross-sectional area of ​​100 nm to 50 μm, 400 nm to 20 μm or 1 μm to 16 μm can be provided.

[0027] In addition, it can be stipulated that the diameter of at least one cross-sectional area is between 0.1 and 10 times the average wavelength (in particular the average wavelength of the electromagnetic wave wavelength range to be preferentially transmitted), in particular between 0.2 and 5 times the average wavelength, or between 0.5 and 2 times the average wavelength.

[0028] As for the geometry of the structural element, it can be provided that the structural element has a non-circular or polygonal geometry, for example a pentagon or a hexagon.

[0029] The first structural element can be designed in particular as a monolithic matrix, for example, with or consisting of a first medium, wherein the first medium has a first refractive index. The second structural element can be designed as a cavity in the matrix, wherein the cavity preferably forms a second refractive index, for example by the refractive index of a liquid, air or gas present as a medium in the cavity. The structural element of the second type can be designed in particular as a monolithic matrix, for example, with or consisting of a second medium, wherein the second medium has the second refractive index. Prior to drawing and redrawing the fused matrix, one or more monolithic matrices of the first medium can be fused to one or more monolithic matrices of the second medium to form a waveguide comprising a plurality of the first matrices and a plurality of the second matrices.

[0030] The cavity in the matrix can be configured as a filamentary channel, i.e., a channel whose cross-sectional area is significantly smaller than the cross-sectional area of ​​the waveguide, for example, and which can be introduced into the matrix in particular by using a laser beam of an ultrashort pulse laser. Furthermore, the filamentary channel in the matrix can be reworked, in particular by chemical or physical etching processes, for example, in order to make the contour of the filamentary channel smoother.

[0031] In particular, when the waveguide is designed as a base body with a cavity, but also independently of the base body, the waveguide can have a greater extension in cross section than in the transport direction. In particular, the waveguide can be designed as a panel.

[0032] The cross-sectional area of ​​the waveguide may be specified to be 1.0 to 50 square centimeters.

[0033] The cross-sectional diameter of the waveguide is at least 2 times, at least 5 times, or at least 10 times longer than the length of the waveguide along the transport direction.

[0034] The substrate with the cavity can be produced or manufactured in a variety of ways. The cavity of the substrate can be constructed by additive manufacturing techniques of the substrate, such as 3D printing processes. Alternatively or additionally, the cavity can be introduced into the substrate subtractively, in particular by introducing the cavity into the substrate in the form of a hole by an abrasive machining method, such as mechanical drilling. Depending on the method used, the hole is not completely limited to a circular geometry.

[0035] The waveguide may be manufactured using a multi-row process, in particular, the waveguide comprises at least a plurality of second structural elements in addition to the plurality of structural elements, wherein the waveguide has at least two surface areas in cross section, wherein each surface area comprises a cross-sectional area of ​​one of the two plurality of second structural elements, and except for rotation and / or reflection, they have the same structure.

[0036] With regard to the length of the waveguide along the transport direction, provision can be made that the length of the waveguide along the transport direction is less than 10 millimeters, less than 6 millimeters, or less than 5 millimeters, in particular when the waveguide is designed as a panel.

[0037] However, in general, it can also be provided that the length of the waveguide along the transport direction is at least 10 mm, at least 20 mm, at least 50 mm, or at least 100 mm.

[0038] In the case where the waveguide is configured as a base body with a cavity, the cavity in the base body, in particular the filamentary channel and / or the hole, can be filled with a second medium having the second refractive index.

[0039] With regard to materials, it can be provided that at least one structural element, in particular the or a first structural element, in particular a structural element constructed as a matrix, includes or consists of one or more of the following materials as a medium: glass (including oxide materials and non-oxide materials, such as chalcogenides), quartz glass, polymers, crystals, single crystals, polycrystalline materials and / or glass ceramics.

[0040] In addition, at least one structural element, in particular the first structural element, in particular the structural element configured as a matrix, may include or consist of a material as a medium, which has an attenuation of less than 100 dB / m, in particular less than 50 dB / m, in particular less than 10 dB / m, in particular less than 1 dB / m in the wavelength range to be transmitted, in particular in the range of 2 μm to 20 μm, in particular, an infrared-transmissive material, in particular a chalcogenide, in particular including: at least one element selected from the group consisting of oxygen, sulfur, selenium and tellurium, and at least one element selected from the group consisting of arsenic, germanium, phosphorus, antimony, lead, boron, aluminum, gallium, indium, titanium, sodium.

[0041] Furthermore, optically active materials can be provided, for example as part of a medium or filler, or as a layer, coating or other modification of the surface of a component of a structural element configured as a rod or tube. Thus, for example, a modification of the guided electromagnetic waves can be achieved, for example an amplification or conversion.

[0042] The further structural element, in particular the or a second structural element, may also comprise or consist of the same material as or a different material than the second structural element.

[0043] The first structural element can be designed, in particular, as a rod-shaped or tubular body, which has or is made of a first medium, which has the first refractive index.

[0044] The second structural element can be constructed, in particular, as a rod-shaped or tubular body having or made of a second medium, the second medium having the second refractive index; and / or as a cavity in the first structural element, the cavity forming the second refractive index or being filled with a second medium having the second refractive index.

[0045] In particular, when the second structural element can be present in the first structural element in the form of a filled cavity, the structural element can be designed as a core-shell system, whereby the core corresponds to the filled cavity.

[0046] A rod-shaped or tubular body should not be understood to mean only a geometric body with a circular cross section.

[0047] The present invention also relates to a method for manufacturing a waveguide, in particular a method for manufacturing a waveguide having one or more of the features described herein, the waveguide being used to transmit electromagnetic waves from a proximal end portion of the waveguide to a distal end portion of the waveguide along a transport direction extending between the proximal end portion and the distal end portion, the method comprising: forming a fiber bundle, the fiber bundle extending along the transport direction and comprising a first structural element and a second structural element different from the first structural element, wherein due to the difference between the first structural element and the second structural element, the electromagnetic wave introduced into the proximal end portion is confined within a cross-sectional area transverse to the transport direction, wherein the forming step comprises arranging the first structural element and the second structural element in the fiber bundle so that the curvature of the fiber bundle is 0.1 m -1 the following. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The following embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings:

[0049] Figure 1(a)-1(e) : Schematic diagrams of cross sections of various waveguides, wherein the waveguides have the following different structural elements: FIG. 1(a), FIG. 1(b), and FIG. 1(c) respectively have two types of structural elements, and FIG. 1(d) and FIG. 1(e) respectively have three types of structural elements, wherein the cross-sectional areas of the structural elements are arranged unevenly;

[0050] Figure 2A and Figure 2B : Cross-sectional images of two glass fiber bundles;

[0051] Figure 3(a)-3(b) : Schematic perspective views of two waveguides having: (a) two types of structural elements whose cross-sectional areas are non-uniformly distributed, and (b) multiple structural elements having non-uniform refractive index (multiple types) and / or non-uniform geometry (diameter);

[0052] Figure 4 : Schematic cross section of a waveguide with two types of structural elements, whose cross-sectional areas are unevenly distributed on a hexagonal grid;

[0053] Figure 5(a)-5(e) : Schematic perspective views of the following waveguides: FIG5 (a) A waveguide assembled into a preform, which is drawn to a certain length; Figure 5(b) , 5(c) Figure 5(d) is a waveguide assembled again into a preform, which is drawn to a certain length; and Figure 5(e) is a waveguide assembled again; and Figure 5(e) is a waveguide fused under pressure;

[0054] Figure 6(a)-6(d) : Figure 5(a)-5(e) The waveguides assembled in the figure again form a schematic cross-section of a preform, where: Figure 5(a) , 5(b) are multiple sections of a waveguide drawn to a certain length; Figure 5(c) , 5(d) To draw multiple sections of two waveguides to a certain length, Figure 5(a) , 5(c) The waveguides are waveguides that do not rotate relative to each other. Figure 5(b) , 5(d) The middle waveguides are waveguides that rotate relative to each other;

[0055] Figure 7(a)-7(f) : Schematic diagrams of various other possibilities of waveguides having structural elements or their cross-sectional areas which are arranged non-uniformly but according to a mathematical manner, each waveguide comprising a plurality of structural elements of a first type and a plurality of structural elements of a second type;

[0056] Figure 8(a)-8(b) : A photograph (and various magnified portions) of a fabricated waveguide having a plurality of structural elements of a first type and a plurality of structural elements of a second type;

[0057] Fig. 9 : Figure 8(a)-8(b) Photograph showing application of waveguide as image conductor;

[0058] Fig. 10A , Fig. 10B and Fig. 10C : The glass fiber bundle in Example 1;

[0059] Fig.11A and Fig. 11B : The glass fiber bundle in Example 2;

[0060] Fig. 12A and Fig. 12B : The glass fiber bundle in Example 3;

[0061] Fig.13A and Fig. 13B : The glass fiber bundle in Example 4;

[0062] Fig.14 : Calculation of curvature;

[0063] Fig.15 : Fig. 10A The image produced by the fiberglass bundle shown;

[0064] Fig.16 : Fig. 10C The image produced by the fiberglass bundle shown;

[0065] Fig.17 : Schematic diagram of the cross section of a fiber bundle;

[0066] Fig.18 : Schematic diagram of a partial cross section of a waveguide. DETAILED DESCRIPTION

[0067] Figure 1(a)-1(e) Various main embodiments of waveguides (100) that can be used for a particular image conductor are shown. The waveguides (100) shown in cross section in the figure each include a plurality of structural elements (10), each of which extends along the transport direction of the waveguide (100), which direction is perpendicular to the figure, and each of which extends proportionally along its cross section. Therefore, each structural element (10) defines a cross-sectional area (20), i.e., a portion of the cross-sectional area of ​​the waveguide (100). The embodiments of the waveguides shown in the figure each have at least two different types of structural elements, whose refractive indices are different. These main embodiments are used to illustrate some variants of inhomogeneity and may deviate in detail from the definitive positioning of the structural elements determined according to the present invention.

[0068] Such a waveguide (100) is used to transmit electromagnetic waves from a proximal end portion of the waveguide (100) to a distal end portion of the waveguide (100) along a conveying direction (5) extending between the proximal end portion (2) and the distal end portion (4) of the waveguide, and the waveguide may include: a fiber bundle (1), the fiber bundle extending along the conveying direction (5) and including a first structural element (10a) and a second structural element (10b) different from the first structural element (10a), wherein due to the difference between the first structural element (10a) and the second structural element (10b), the electromagnetic waves introduced into the proximal end portion (2) are confined within a cross-sectional area transverse to the conveying direction (5), wherein the curvature of the fiber bundle (1) is 0.1 m -1 As explained above, the curvature of the present invention refers to a reduced amount of bending compared to conventional Anderson localized fiber bundles, which can reduce the possibility of noise, reduce the possibility of mechanical failure, and increase the possibility that the fiber bundle can be incorporated into the waveguide (100). See Fig.17 A, which depicts a cross section of a fiber bundle (1) consisting of a plurality of first and second structural elements (10); see Fig.17 B, which depicts a partial cross section of a waveguide (100) composed of a plurality of fiber bundles (1).

[0069] like Fig.14 As shown, the curvature is measured in the following manner: the fiber bundle is placed on a plane; then, the length L of the fiber bundle is measured along the image delivery direction; then, the height H, which is the distance between the midpoint of the fiber bundle and the axis, which intersects the center of the image input end of the fiber bundle and the image output end of the fiber bundle, is measured; then, the radius of curvature R is calculated using the following formula. The curvature (unit: m -1 ) is the reciprocal of R:

[0070]

[0071] In some embodiments, the curvature is 0.1 m -1 Below, 0.09m -1 Below, 0.08m -1 Below, 0.07m -1 Below, 0.06m -1 Below, 0.05m -1 Below, 0.04m -1 Below, 0.03m -1 Below, 0.02m -1 Below, 0.01m -1 Below and / or greater than 0m -1 .

[0072] The net CTE modulus of the fiber bundle can be 0.0100 ppm / K or less, 0.0075 ppm / K or less, 0.0050 ppm / K or less, 0.0025 ppm / K or less, and / or 0 m or more. One method of achieving the desired curvature described herein is to manufacture the fiber bundle so that the fiber bundle has the net CTE modulus. Methods for calculating the net CTE modulus and methods for manufacturing fiber bundles to achieve the net CTE modulus are described herein.

[0073] The waveguide (100) shown in cross section in FIG. 1( a) has a first structural element 10a configured as a matrix, which accommodates a plurality of second structural elements 10b. Thus, the second structural elements 10b can be configured, for example, as cavities or hollow channels extending in the transport direction in the first structural element 10a. In this case, the first structural element 10a configured as a matrix comprises a first material having a first refractive index, and the second structural element 10b configured as a cavity forms a second refractive index, for example, by air or other gas contained therein. In this case, the cross-sectional area 20 of the first structural element corresponds to the area of ​​the waveguide (100) minus the area of ​​the holes defined by the cavities, while the cross-sectional areas 20 of the second structural elements 10b each correspond to the cross-sectional area of ​​the cavities. However, the cavities of the body can also be filled with a second material, so that the second structural elements 10b correspond to the filled cavities. As schematically shown in the figure, the cross-sectional areas 20 of the second structural elements 10b are non-uniform, because their positions are not uniformly distributed in the cross section, in particular, they are not located on a periodic grid. At the same time, however, the position of the structural element is determined mathematically, as described in more detail herein.

[0074] The waveguide (100) shown in cross section in Figure 1(b) has two types of structural elements 10a, 10b, namely a structural element 10a configured as a matrix and having a first refractive index and a plurality of structural elements 10b having a second refractive index different from the first refractive index. In the embodiment shown, the cross-sectional area 20 of the second structural element 10b is not only arranged non-uniformly, but also has a non-uniform geometry, in this case, a non-uniform diameter.

[0075] The waveguide (100) shown in cross section in FIG. 1( c) also has two types of structural elements 10a, 10b, wherein the cross-sectional area of ​​the second structural element 10b is each arranged in the first structural element 10a (in particular as a core-sheath system). Thus, in this case, a plurality of first structural elements 10a and a plurality of second structural elements 10b are provided. The structural elements or their cross-sectional areas are constructed inhomogeneously, so that the first structural elements 10a (accommodating the second structural elements 10b) are arranged inhomogeneously (in particular non-periodically) in the cross section of the waveguide (100), and this arrangement is determined mathematically.

[0076] The waveguide (100) shown in cross section in Figures 1(d) and 1(e) corresponds in some respects to the waveguide (100) shown in Figures 1(a) and 1(b), but has three types of structural elements 10a, 10b, 10c with different refractive indices. In particular, the cavities in the structural element 10a configured as a matrix can be filled with different media. Therefore, the structural elements 10b, 10c have inhomogeneities in particular, because their refractive indices are different from each other.

[0077] Fiber bundles can be manufactured with 0.1 m -1 One method of achieving this curvature is to manufacture the fiber bundle so that the net CTE modulus of the fiber bundle is less than 0.01 ppm / K.

[0078] The net CTE module is calculated mathematically as follows.

[0079] For waveguides formed by combining multiple structural elements to form a fiber bundle, which is then combined to form the waveguide, the calculation is performed on the cross-section of a single fiber bundle, since a single fiber bundle is the repeating unit that forms the waveguide. For waveguides formed by combining multiple structural elements to form the entire waveguide without the intermediate step of forming and combining multiple fiber bundles, the calculation is performed on the cross-section of the entire waveguide, since there is no repeating unit of a single fiber bundle. If the waveguide is formed by combining two or more different fiber bundles, the calculation is performed separately on the cross-section of each fiber bundle. In cases where a single fiber bundle cannot be identified, such as when analyzing the manufactured waveguide to determine its characteristics, the calculation is performed on the cross-section of the smallest, identifiable repeating unit, and if there are two or more different identifiable repeating units, the calculation is performed on the cross-section of each repeating unit.

[0080] The first step in this calculation is to acquire an actual image of the reference fiber bundle with a resolution of at least 20 pixels and bisect a cross section along its two principal axes, specifically the horizontal x-axis and the vertical y-axis of a Cartesian coordinate system. The two principal axes are perpendicular to each other and are located at the geometric center of the fiber bundle, e.g. Figure 2A The geometric center of the hexagonal cross section shown, or Figure 2B The geometric center of the circular cross section shown. Figure 2A and 2B This bisection is shown to create four quadrants, with Quadrant 1 opposite Quadrant 3 and Quadrant 2 opposite Quadrant 4. For asymmetrical cross-sectional shapes such as polygons or circles, two principal axis bisections at the geometric center are still required to create four quadrants.

[0081] Next, the coordinate (0, 0) is assigned to the center of the geometry and the CTE along the x and y axes is calculated as follows:

[0082]

[0083] A T = number of pixels in the fiber bundle image

[0084] A k,l = Area of ​​one pixel

[0085] X k,l = the horizontal coordinate of each pixel relative to the geometric center

[0086] Y k,l = vertical coordinate of each pixel relative to the geometric center

[0087] α k,l = CTE of pixel at x,y coordinate

[0088] αx = CTE along the x-axis

[0089] α y = CTE along the y-axis

[0090] The net CTE modulus is calculated as follows:

[0091] net

[0092] If the net CTE modulus is not below 0.01ppm / K, this indicates that the fiber bundle may not have 0.1m -1 In order to obtain this ideal curvature in the next fiber bundle to be manufactured, it may be necessary to rearrange the position of each structural element in the next fiber bundle to be manufactured relative to its adjacent structural elements so that the final net CTE modulus of the newly manufactured fiber bundle is less than 0.01 ppm / K. For example, such relocation may be the position of one or more first structural elements and second structural elements, so that their x and y coordinates are moved relative to other structural elements, so that when the net CTE modulus of the new fiber bundle is calculated, the net CTE modulus of the new fiber bundle will be less than 0.01 ppm / K, and the curvature of the new fiber bundle may be 0.1 m -1 If necessary, this rearrangement / rearrangement of the positions of the first structural material and the second structural material is performed multiple times until a net CTE modulus of less than 0.01 ppm / K is achieved.

[0093] One possible way to determine which optical structural elements should be rearranged is to consider α x and α y The sign and magnitude of . For example, 1) α x The positive sign and α y The positive sign of indicates that the structural elements in the first quadrant have too many higher expansion structural elements, and a certain number of high expansion structural elements in the first quadrant should be replaced by the same number of low expansion structural elements from the opposite third quadrant; 2) α x The negative sign and α y The positive sign of indicates that the structural elements in the second quadrant have too many higher expansion structural elements, and a certain number of high expansion structural elements in the second quadrant should be replaced by the same number of low expansion structural elements from the opposite fourth quadrant; 3) α x The negative sign and α y The negative sign of indicates that the structural elements in the third quadrant have too many higher expansion structural elements, and a certain number of high expansion structural elements in the third quadrant should be replaced by the same number of low expansion structural elements from the opposite first quadrant; and 4) α x The positive sign and α yThe negative sign of indicates that the structural elements in the fourth quadrant have too many higher expansion structural elements, and a certain number of high expansion structural elements in the fourth quadrant should be replaced by the same number of low expansion structural elements from the opposite second quadrant.

[0094] In addition to substitution between opposite quadrants, substitution may additionally or alternatively be performed between adjacent quadrants. In addition, substitution may be performed within the same quadrant by moving the high expansion structural element closer to the coordinate (0, 0), but this may result in clustering and partial symmetry of the high expansion structural elements. Furthermore, during any of these substitutions, it may be necessary to rearrange other high thermal expansion and low thermal expansion structural elements to avoid creating a symmetric ordered pattern that is not conducive to Anderson localization.

[0095] The replacement of high thermal expansion structural elements with low thermal expansion structural elements can be continued until the desired new CTE modulus is reached, for example, below 0.015 m.

[0096] Figure 3(a)-3(b) Two further embodiments of a waveguide (100) that can be used for a particular image conductor are shown. The waveguide (100) comprises a plurality of first and second structural elements 10, each extending along a transport direction 5 from a proximal end 2 to a distal end 4 of the waveguide (100), and each structural element is, for example, rod-shaped.

[0097] The waveguide (100) shown in FIG3(a) includes a plurality of first structural elements 10a and a plurality of second structural elements 10b. The arrangement of the structural elements is not uniform because the first structural elements 10a and the second structural elements 10b are arranged and / or distributed in a non-uniform manner, which should be determined mathematically as described herein to achieve a desired net CTE modulus, thereby obtaining a desired curvature, although Figure 3(a)-3(b) Arrangements that achieve a desired net CTE modulus or curvature are not necessarily shown.

[0098] The waveguide (100) shown in FIG3(b) comprises a plurality of structural elements 10, wherein in this embodiment, the cross-sectional area of ​​the structural elements has a non-uniform geometry. In particular, the geometry differs in that the diameters of the structural elements or their cross-sectional areas differ from one another. Furthermore, each structural element 10 in FIG3(a) and FIG3(b) may exhibit non-uniformity because the refractive indices of these structural elements differ from one another. In this regard, a discrete number of different refractive indices may be provided, such as 2, 3, 4, etc.

[0099] Figure 4 A cross-section of a fiber bundle (1) is shown, which corresponds in some respects to the waveguide (100) shown in Figure 3(a). Figure 4 The fiber bundle (1) shown has a plurality of, in particular, rod-shaped structural elements 10, namely a plurality of first structural elements 10a and a plurality of second structural elements 10b, which are arranged in a hexagonal grid in cross section. At least one of the structural elements 10 or its cross-sectional area 20 is equidistant from six adjacent structural elements 10 or their cross-sectional areas 20, preferably adjacent.

[0100] Figure 5(a)-5(e) The method steps for manufacturing a waveguide according to the multiple drawing method are shown. In this process, a plurality of waveguides are assembled to form a preform 30 and drawn to a certain length (Figure 5 (a)). For example, the waveguide can be, for example, according to Figure 4 The arrangement of the structural elements 10, 20 or 10a, 10b, or for example according to Figure 1(a) to Figure 1(e) Alternative arrangements of structural elements to those shown in , which may have been drawn in a known manner. Ideally, the structural elements are positioned relative to each other to achieve the desired net CTE modulus.

[0101] The assembled and elongated waveguide ("multi-fiber") is then disassembled into multiple parts and assembled again into a preform 40 (FIG. 5(b), "multi-multi assembly"). The preform 40 can then be drawn to length again (FIG. 5(c)) and, if necessary, disassembled into multiple parts again and assembled (FIG. 5(d)). Finally, the assembly thus obtained can be welded by applying heat and / or pressure, in particular under vacuum (FIG. 5(e)).

[0102] refer to Figure 6(a)-6(d) , during the assembly process, the assembled fiber bundles ("multi-fibers", here "M1") drawn to a certain length can be assembled into another preform in a manner that is not rotated relative to each other (Figure 6(a)) or rotated relative to each other (Figure 6(b)). In addition, during the assembly process, parts from at least two different assembled fiber bundles ("M1", "M2") drawn to a certain length can be assembled without rotating relative to each other (Figure 6(c)) or rotated relative to each other (Figure 6(d)). Similar to the arrangements shown in Figures 6(a) and 6(b), when assembling the first preform, the fiber bundles can also be arranged either without rotating relative to each other or rotated relative to each other.

[0103] refer to Figure 7(a)-7(f) , various embodiments of structural element inhomogeneity will be discussed again below by way of example. As previously mentioned, the structural elements, and in particular their cross-sectional areas, are characterized on the one hand by their inhomogeneity with respect to one another, and on the other hand by the degree of regularity, such that the inhomogeneity of the structural elements is predetermined to achieve a desired net CTE modulus.

[0104] Figure 7(a)-7(f) Some fiber bundles (1) are shown, each having a plurality of structural elements of a first type and a plurality of structural elements of a second type (and sometimes other types in FIG. 7( d )). In particular, the fiber bundles (1) shown here do not have any matrix material, but rather the structural elements are adjacent to each other. Figure 7(a)-7(f) The fiber bundles (1) shown in FIG. 1 have in common that different types of structural elements, in particular their cross-sectional areas, are positioned periodically to achieve a desired net CTE modulus.

[0105] FIG. 7( a ) shows a fiber bundle ( 1 ) generally having a plurality of structural elements 10 a and a plurality of structural elements 10 b , which have different refractive indices.

[0106] Fig. 7(b) shows a fiber bundle (1) having a plurality of structural elements 10d and a plurality of structural elements 10e, which have different refractive indices and different substructures, the substructures being defined by substructure elements 10a and 10b (having refractive indices a and b) and 10a and 10c (having refractive indices a and c), respectively. The substructures here refer to structural elements 10d and 10e constructed as core-shell systems having different cores.

[0107] FIG. 7( c ) also shows a fiber bundle ( 1 ) having a plurality of structural elements 10 d and a plurality of structural elements 10 e, which have different refractive indices and different substructures, the substructures being defined by substructure elements 10 a and 10 b (having refractive indices a and b) and 10 c and 10 b (having refractive indices c and d), respectively. The substructures here are structural elements 10 d and 10 e constructed as core-cladding systems with different claddings.

[0108] FIG7( d) also shows a fiber bundle (1) having a plurality of structural elements 10e, a plurality of structural elements 10f, a plurality of structural elements 10g and a plurality of structural elements 10h, which have different refractive indices and different substructures, wherein the substructures are represented by substructure elements 10a and 10b (having refractive indices a and b), 10a and 10c (having refractive indices a and c), 10b and 10d (having refractive indices b and d), and 10c and 10d (having refractive indices c and d), respectively. The substructures here refer to structural elements 10e, 10f, 10g and 10h constructed as core-shell systems with different shells and different cores.

[0109] Figure 7(e) shows a fiber bundle (1) having a plurality of structural elements 10c and a plurality of structural elements 10d, which have different geometries and different substructures, wherein the substructure of the structural element 10c is defined by the substructure elements 10a and 10b (having refractive indices a and b and a first core diameter), and the substructure of the structural element 10d is defined by the substructure elements 10a and 10b (having refractive indices a and b and a second core diameter).

[0110] Figure 7(f) shows a fiber bundle (1) having multiple structural elements 10c and multiple structural elements 10d, which have different geometries and different substructures, wherein the substructure of the structural element 10c is defined by the substructure elements 10a and 10b (having refractive indices a and b and a centrally positioned core), and the substructure of the structural element 10d is defined by the substructure elements 10a and 10b (having refractive indices a and b and an eccentrically positioned core).

[0111] FIG8(a) shows a photograph as an example of a fiber bundle (1) having: a plurality of fibers having a first refractive index as a first structural element 10a, and a plurality of fibers having a second refractive index as a second structural element 10b; and FIG8(b) is an enlarged view and a sketch thereof. In this case, the fibers of the structural elements 10a and 10b are adjacent to each other and positioned, and the net CTE modulus can be calculated. The first type of structural element 10a and the second type of structural element 10b can be surrounded by a third type of structural element 10c configured as a cladding tube. The refractive index of the cladding tube can be lower than the refractive index of the first type of structural element 10a and the refractive index of the second type of structural element 10b.

[0112] Fig. 9 A photograph showing the application of the fiber bundle (1) of FIG8(a) as an image conductor is shown, and the fiber bundle is used to transmit an image showing the number 5. Due to the uneven arrangement of the structural elements, image transmission with high resolution based on the lateral Anderson localization phenomenon is achieved here.

[0113] In summary, a waveguide (100) can be configured to transmit electromagnetic waves from a proximal end portion of the waveguide (100) to a distal end portion of the waveguide (100) along a transport direction (5) extending between the proximal end portion (2) and the distal end portion (4). The waveguide (100) can have a fiber bundle (1), the fiber bundle (1) extending along the transport direction (5) and having a first structural element (10a) and a second structural element (10b) different from the first structural element (10a). Due to the difference between the first structural element (10a) and the second structural element (10b), the electromagnetic waves introduced into the proximal end portion (2) are confined within a cross-sectional area transverse to the transport direction (5). The net CTE modulus of the fiber bundle (1) can be less than 0.01 ppm / K, and the curvature can be 0.1 m / s.-1 the following.

[0114] The CTE of the first structural element (10a) may differ from the CTE of the second structural element (10b) by less than 5 ppm / K, or when one of the structural elements is a cavity filled with air, by less than 3,690 ppm / K.

[0115] The fiber bundle (1) may include a plurality of first structural elements (10a) and a plurality of second structural elements (10b), and the waveguide (100) may include a plurality of fiber bundles (1). The total number of first structural elements (10a) and second structural elements (10b) in the fiber bundle (1) may be sufficient to produce a centered polygonal unit, for example, the fiber bundle has 20 to 300 structural elements or 50 to 300 structural elements, for example Figure 2A and Figure 2B The 61 structural elements shown.

[0116] One or more first structural elements (10a) can be welded to one or more second structural elements (10b). The second structural elements (10b) are air passages located within a matrix formed by the first structural elements (10a). Each individual first structural element (10a) and each individual second structural element (10b) need not be surrounded by a coating layer.

[0117] When viewed from a cross section of the fiber bundle (1), the plurality of first structural elements (10a) and the plurality of second structural elements (10b) may be arranged unevenly. When viewed from a cross section of the fiber bundle (1), the first structural elements (10a) and the second structural elements (10b) may have exactly the same composition but different diameters.

[0118] A method for transmitting electromagnetic waves from a proximal end portion of a waveguide (100) to a distal end portion of the waveguide (100) along a transmission direction (5) extending between a proximal end portion (2) of the waveguide (100) and a distal end portion (4) of the waveguide (100) may include the steps of: determining a desired curvature of the waveguide (100); and manufacturing the waveguide (100) to achieve the desired curvature. The method may include the steps of: forming a fiber bundle (1), the fiber bundle extending along the transmission direction (5) and including a first structural element (10a) and a second structural element (10b) different from the first structural element (10a), wherein due to the difference between the first structural element (10a) and the second structural element (10b), the electromagnetic waves introduced into the proximal end portion (2) are confined within a cross-sectional area transverse to the transmission direction (5), and wherein the forming step includes arranging the first structural element (10a) and the second structural element (10b) in the fiber bundle (1) so that the curvature of the fiber bundle (1) is 0.1 m / s. -1 the following.

[0119] Example :

[0120] The following waveguides were prepared and analyzed.

[0121] Example 1 :

[0122] A glass fiber bundle was prepared having a plurality of first structural elements having a CTE of 5 ppm / K and a plurality of second structural elements having a CTE of 7.3 ppm / K. Fig. 10A As shown (the first structural element is represented by a line, and the second structural element is represented by a wavy line), the position of each structural element is set arbitrarily. The net CTE modulus is 0.0383ppm / K. The curvature is 0.083m -1 The generated image is as follows Fig.15 shown.

[0123] α of the first glass fiber bundle x -0.0171ppm / K, α y =-0.342ppm / K, which means that there are too many high expansion fibers in the third quadrant. In order to reduce the net CTE modulus and reduce the curvature, such as Fig. 10B As shown, several structural elements in the third quadrant are rearranged to the first and second quadrants, thereby producing the following Fig. 10C The second glass fiber bundle shown has a x -0.0043ppm / K, α y is -0.0086ppm / K, so the net CTE modulus is 0.0096ppm / K. The curvature is between 0m -1 and 0.01m -1 The generated image is between Fig.16 Shown in.

[0124] Example 2 :

[0125] The first structural element and the second structural element in Example 1 are Fig.11A The net CTE modulus is 0.1213 ppm / K.

[0126] α of the first glass fiber bundle x 0.1115ppm / K, α y =-0.0478 ppm / K, which means that there are too many high expansion fibers in the fourth quadrant. In order to reduce the net CTE modulus and reduce the curvature, several structural elements in the fourth quadrant are rearranged to the second and third quadrants, resulting in Fig. 11B The second glass fiber bundle shown has a x 0ppm / K, α yis 0 ppm / K, therefore, the net CTE modulus is 0 ppm / K.

[0127] Example 3 :

[0128] The first structural element and the second structural element in Example 1 are Fig. 12A The net CTE modulus is 0.1051 ppm / K.

[0129] α of the first glass fiber bundle x 0.0798ppm / K, α y =-0.0684 ppm / K, which means that there are too many high expansion fibers in the fourth quadrant. In order to reduce the net CTE modulus and reduce the curvature, several structural elements in the fourth quadrant are rearranged to the second and first quadrants, resulting in Fig. 12B The second glass fiber bundle shown has a x 0ppm / K, α y is 0ppm / K, so the net CTE modulus is 0ppm / K.

[0130] Example 4 :

[0131] The first structural element and the second structural element in Example 1 are Fig.13A Arranged in the manner shown. The net CTE modulus is 0.0756 ppm / K.

[0132] α of the first glass fiber bundle x 0.0750ppm / K, α y is 0.0100 ppm / K, which means that there are too many high expansion fibers in the first quadrant. In order to reduce the net CTE modulus and reduce the curvature, several structural elements in the first quadrant are rearranged to the third and fourth quadrants, resulting in Fig. 13B The second glass fiber bundle shown has a x 0ppm / K, α y is 0ppm / K, so the net CTE modulus is 0ppm / K.

Claims

1. A waveguide (100) for transmitting electromagnetic waves from a proximal end (2) of the waveguide (100) to a distal end (4) of the waveguide (100) along a transmission direction (5) extending between the proximal end (2) and the distal end (4), the waveguide (100) comprising: A fiber bundle (1) extending in the transport direction (5) and comprising a disordered arrangement of a first structural element (10a) and a second structural element (10b) different from the first structural element (10a), wherein due to the difference between the first structural element (10a) and the second structural element (10b), an electromagnetic wave introduced into the proximal end (2) is confined within a cross-sectional area transverse to the transport direction (5), The curvature of the fiber bundle (1) is 0.1 m -1 the following.

2. The waveguide according to claim 1, wherein The curvature of the fiber bundle (1) is greater than 0 m -1 Up to 0.1m -1 .

3. The waveguide according to claim 1, wherein The net CTE modulus of the fiber bundle (1) is less than 0.01 ppm / K.

4. The waveguide according to claim 1, wherein: The net CTE modulus of the fiber bundle (1) is 0 ppm / K to 0.01 ppm / K.

5. The waveguide according to claim 1, wherein The CTE of the first structural element (10a) differs from the CTE of the second structural element (10b) by less than 5 ppm / K.

6. The waveguide according to claim 1, wherein The fiber bundle (1) comprises a plurality of first structural elements (10a) and a plurality of second structural elements (10b).

7. The waveguide according to claim 6, wherein: The waveguide (100) comprises a plurality of fiber bundles (1).

8. The waveguide according to claim 6, wherein: The fiber bundle (1) comprises a first structural element (10a) and a plurality of second structural elements (10b), the total number of which is 20 to 300.

9. The waveguide according to claim 1, wherein: One or more of the first structural elements (10a) are welded to one or more of the second structural elements (10b).

10. The waveguide according to claim 1, wherein The second structural element (10b) is an air channel located within the matrix formed by the first structural element (10a).

11. The light guide according to claim 1, wherein Each individual first structural element (10a) and each individual second structural element (10b) are not surrounded by a coating layer.

12. The waveguide according to claim 1, wherein When viewed from a cross section of the fiber bundle (1), a plurality of first structural elements (10a) and a plurality of second structural elements (10b) are arranged unevenly.

13. A method of manufacturing a waveguide (100) for transmitting electromagnetic waves from a proximal end portion of the waveguide (100) to a distal end portion of the waveguide (100) along a transmission direction (5) extending between a proximal end portion (2) and a distal end portion (4), the method comprising: determining an expected curvature of the waveguide (100); as well as The waveguide (100) is manufactured to achieve the desired curvature.

14. A method of manufacturing a waveguide (100) for transmitting electromagnetic waves from a proximal end portion of the waveguide (100) to a distal end portion of the waveguide (100) along a transmission direction (5) extending between a proximal end portion (2) and a distal end portion (4), the method comprising: A fiber bundle (1) is formed, the fiber bundle (1) extending in the conveying direction (5) and comprising a first structural element (10a) and a second structural element (10b) different from the first structural element (10a), wherein due to the difference between the first structural element (10a) and the second structural element (10b), the electromagnetic wave introduced into the proximal end portion (2) is confined within a cross-sectional area transverse to the conveying direction (5), The forming step comprises arranging the first structural element (10a) and the second structural element (10b) in the fiber bundle (1) so that the curvature of the fiber bundle (1) is 0.1 m -1 the following.

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