Mode multiplexer / demultiplexer using metamaterials for optical communication systems and optical communications

Abstract

An optical system comprising: (i) a plurality of input optical fibers; (ii) an optical mode multiplexer / demultiplexer coupled to the input optical fibers, the optical mode multiplexer / demultiplexer including a plurality of metamaterial structures having a length and forming at least one level of metamaterial, the at least one level of metamaterial being located on a surface of the optical mode multiplexer / demultiplexer facing the input optical fibers, and the at least one level of metamaterial being oriented at an angle between 60 degrees and 120 degrees with respect to an axis of the input optical fibers; and the super surface being configured to receive a first optical signal having a first mode from at least one of the plurality of input optical fibers and to convert the first mode to a different mode.

Description

[0001] Related Applications

[0002] This application claims priority benefit under 35 U.S.C. § 119 to U.S. Provisional Application No. 63 / 085,361, filed September 30, 2020, priority benefit under 35 U.S.C. § 119 to U.S. Provisional Application No. 62 / 968,549, filed January 31, 2020, and priority benefit under 35 U.S.C. § 119 to U.S. Provisional Application No. 62 / 968,531, filed January 31, 2020, the contents of which are relied upon and incorporated herein by reference in their entirety. BACKGROUND

[0003] The following relates generally to one or more fiber optic communication systems, and more particularly to mode multiplexers or demultiplexers for fiber optic communications using metamaterials.

[0004] Optical communication systems are widely deployed to provide various types of communication content, such as voice content, video content, packet data, messaging, broadcast content, and so on. Optical communication systems rely on various types of adjustments to optical signals on a common transmission fiber to increase the amount of information that can be transmitted over the transmission fiber. SUMMARY

[0005] The systems, methods, and devices of the disclosure each have several novel and innovative aspects. The following Overview provides a brief overview of some of these novel and innovative aspects, but the disclosure can include aspects that are not included in the following Overview.

[0006] According to one specific embodiment, an optical system comprises:

[0007] (i) a plurality of input optical fibers;

[0008] (ii) an optical mode multiplexer coupled to the input optical fibers, the optical mode multiplexer including a plurality of metamaterial structures having a length / and forming at least a first order metamaterial having a length L and a width W, and

[0009] a. the at least first order metamaterial is located on a surface of the optical mode multiplexer / demultiplexer facing the input optical fibers, and the at least first order metamaterial is oriented at an angle between 60 degrees and 120 degrees relative to an axis of the input optical fibers; and

[0010] b. the metasurface is configured to receive a first optical signal having a first mode from at least one of the plurality of input optical fibers and convert the first mode to a different mode.

[0011] According to one specific embodiment, an optical system comprises:

[0012] (iii) a plurality of input optical fibers;

[0013] (iv) an optical mode multiplexer coupled to the input optical fibers, the optical mode multiplexer comprising a plurality of metamaterial structures having a length / and forming at least one level of metamaterial having a length L and a width W, and

[0014] a. the at least one level of metamaterial is located on a surface of the optical mode multiplexer / demultiplexer facing the input optical fibers, and the length L of the at least one level of metamaterial is oriented at an angle between 60 degrees and 120 degrees relative to an axis of the input optical fibers; and

[0015] b. the metasurface is configured to receive a first optical signal having a first mode from at least one of the plurality of input optical fibers and convert the first mode to a different mode.

[0016] According to some embodiments, an optical system, comprising:

[0017] (i) a plurality of input optical fibers;

[0018] (ii) an optical mode multiplexer / demultiplexer coupled to the input optical fibers, the optical mode multiplexer / demultiplexer comprising a plurality of metamaterial structures arranged in an A x B array, where A > 3 and B > 3, the metamaterial structures forming at least one level of metamaterial, and

[0019] a. the at least one level of metamaterial is located on a surface of the optical mode multiplexer / demultiplexer such that a plane of the metasurface is oriented at an angle between 60 degrees and 120 degrees relative to an axis of the input optical fibers; and

[0020] b. the metasurface is configured to receive a first optical signal having a first mode from at least one of the plurality of input optical fibers and convert the first mode to a different mode.

[0021] According to some embodiments, A > 5, B > 5, and the plurality of metamaterial structures is greater than 500. According to some embodiments, A > 5, B > 5, and the plurality of metamaterial structures is greater than 1000 (e.g., greater than 10,000 or greater than 100,000). According to some embodiments, A > 5, B > 5, and the plurality of metamaterial structures is greater than 500. According to some embodiments, A > 5, B > 5, and the plurality of metamaterial structures is greater than 1000 (e.g., greater than 10,000 or greater than 100,000, or even greater than 10,000,000). According to some embodiments, A > 10, B > 10, and the plurality of metamaterial structures is greater than 1000. According to some embodiments, A > 10, B > 10, and the plurality of metamaterial structures is greater than 1000 (e.g., greater than 10,000 or greater than 100,000). According to some embodiments, A > 100, B > 100, and the plurality of metamaterial structures is greater than 10,000,000. According to some embodiments, 10,000,000 > A > 10; 10,000,000 > B > 10; and the plurality of metamaterial structures is greater than 10,000,000 (e.g., not less than 100,000,000).

[0022] According to some embodiments, the mode multiplexer / demultiplexer includes a substrate having a thickness > 5 μιη (e.g., a thickness > 20 μιη, or even > 100 μιη).

[0023] According to some embodiments, the optical mode multiplexer is directly coupled to the input optical fiber without a focusing lens between them. According to some embodiments, the at least one level of metamaterial is oriented at an angle between 70 degrees and 110 degrees (e.g., between 80 and 100 degrees, or between 84 and 97 degrees) relative to an axis of the input optical fiber. According to some embodiments, the at least one level of metamaterial is oriented at an angle of 89 degrees to 91 degrees relative to an axis of the input optical fiber. According to some embodiments, the at least one level of metamaterial is not oriented at a right angle relative to an axis of the input optical fiber. According to some embodiments, the at least one level of metamaterial is oriented at a right angle (90 degrees) relative to an axis of the input optical fiber. According to some embodiments, 100 mm > L > 10 μιη, and 100 mm > W > 10 μιη, e.g., 50 mm > L > 50 μιη, and 50 mm > W > 50 μιη, or 50 mm > L > 200 μιη, and 50 mm > W > 200 μιη.

[0024] According to some embodiments, the optical system further comprises at least one multi-core or multi-mode fiber optically coupled to the optical mode multiplexer, wherein the at least one multi-core or multi-mode fiber receives the output beams from the optical mode multiplexer. According to some embodiments, the at least one multi-core or multi-mode fiber is coupled to the optical mode multiplexer and receives different optical modes from the optical mode multiplexer without any focusing lens placed between the optical mode multiplexer and the at least one multi-core or multi-mode fiber.

[0025] According to some embodiments, the input fibers are directly attached to the input surface of the optical multiplexer. According to some embodiments, the input fibers are coupled to the optical mode multiplexer by connectors or couplers.

[0026] According to some embodiments, each of the plurality of metamaterial structures has a length / , where 5 μm > / > 100 nm, such as 10 μm > / > 50 nm. According to some embodiments, each of the plurality of metamaterial structures has a length / , where 5 μm > / > 100 nm, and the lengths of the plurality of metamaterial structures are oriented perpendicular to the substrate. According to some embodiments, each of the plurality of metamaterial structures has a length / , where 5 μm > / > 100 nm (such as between 200 nm and 5 microns), and the lengths of the plurality of metamaterial structures are oriented parallel to the axis of the input fiber. According to at least some embodiments, the plurality of metamaterial structures are arranged in an array of at least 3x3. According to at least some embodiments, the plurality of metamaterial structures are arranged in an array of at least 3x3. According to some embodiments, the at least one level of metamaterials comprises at least 1000 metamaterial structures.

[0027] According to some embodiments, an optical system, comprising:

[0028] (i) N input fibers, wherein the input fibers are single mode fibers and N > 2;

[0029] (ii) an optical mode multiplexer or demultiplexer coupled to the input fibers and comprising M levels of metamaterials, where M > 2;

[0030] (iii) and at least one multi-core or multi-mode fiber coupled to the optical mode multiplexer or demultiplexer, wherein the optical mode multiplexer or demultiplexer is configured to convert single mode inputs received from the input fibers into N different spatial modes and send them through the multi-core or multi-mode fiber

[0031] (iv) the optical mode multiplexer or demultiplexer comprises a plurality of metamaterial structures having a length / , and forms at least one level of metamaterials having a length L and a width W, and

[0032] a. at least one level of metamaterial is located on a surface of the optical mode multiplexer facing the input optical fiber such that the at least one level of metamaterial faces the input optical fiber and a length L of the at least one level of metamaterial is oriented at an angle between 60 degrees and 120 degrees relative to an axis of the input optical fiber; and

[0033] b. the metasurface is configured to receive a first optical signal having a first mode from at least one of the plurality of input optical fibers and convert the first mode to a different mode.

[0034] According to some embodiments, an optical system comprises:

[0035] (i) N input optical fibers, wherein the input optical fibers are single mode optical fibers and N > 2;

[0036] (ii) an optical mode multiplexer or demultiplexer coupled to the input optical fibers and comprising M levels of metamaterials, wherein M > 2;

[0037] (iii) and at least one multi-core or multi-mode optical fiber coupled to the optical mode multiplexer or demultiplexer, wherein the optical mode multiplexer or demultiplexer is configured to convert single mode inputs received from the input optical fibers to N different spatial modes and send them through the multi-core or multi-mode optical fiber

[0038] (iv) the optical mode multiplexer or demultiplexer comprises a plurality of metamaterial structures having a length / and forms at least one level of metamaterial having a length L and a width W, and

[0039] a. at least one level of metamaterial is located on a surface of the optical mode multiplexer facing the at least one multi-core or multi-mode optical fiber such that the at least one level of metamaterial faces the input optical fiber and a length L of the at least one level of metamaterial is oriented at an angle between 60 degrees and 120 degrees relative to an axis of the input optical fiber; and

[0040] b. the metasurface is configured to receive a first optical signal having a first mode from at least one of the plurality of input optical fibers and convert the first mode to a different mode.

[0041] An optical system comprises:

[0042] (i) N input optical fibers, wherein the input optical fibers are single mode optical fibers and N > 2;

[0043] (ii) an optical mode multiplexer or demultiplexer coupled to the input optical fibers and comprising M levels of metamaterials, wherein M > 2;

[0044] (iii) and at least one multi-core or multi-mode optical fiber, the at least one multi-core or multi-mode optical fiber coupled to the optical mode multiplexer or demultiplexer, wherein the optical mode multiplexer or demultiplexer is configured to convert a single mode input received from the input optical fiber into N different spatial modes and send them through the multi-core or multi-mode optical fiber

[0045] (iv) the optical mode multiplexer or demultiplexer includes a plurality of metamaterial structures having a length / and forms at least one level of metamaterial having a length L and a width W, and

[0046] a. the at least one level of metamaterial is located on a surface of the optical mode multiplexer facing the at least one multi-core or multi-mode optical fiber, such that the at least one level of metamaterial faces the input optical fiber, and the length L of the at least one level of metamaterial is oriented at an angle between 60 degrees and 120 degrees with respect to an axis of the input optical fiber; and

[0047] The metasurface is configured to receive a first optical signal having a first mode from at least one of the plurality of input optical fibers and convert the first mode to a different mode.

[0048] An apparatus can include a first substrate that is optically transmissive; a first metamaterial level positioned proximate to or in contact with the first substrate; a second metamaterial level positioned proximate to or in contact with the first substrate, the first metamaterial level and the second metamaterial level configured to: receive a second optical signal having a second mode through a second optical communication link; generate a third optical signal having a third mode by shifting a first phase profile of the first optical signal; generate a fourth optical signal having a fourth mode by shifting a second phase profile of the second optical signal; and transmit the third optical signal and the fourth optical signal through a third optical communication link, the third optical communication link comprising a multi-mode optical communication link.

[0049] In some examples, the first metamaterial level can be configured to shift a first phase profile of the first optical signal and a second phase profile of the second optical signal and output a first shifted optical signal and a second shifted optical signal, and the second metamaterial level can be configured to shift a third phase profile of the first shifted optical signal and a fourth phase profile of the second shifted optical signal and output a third optical signal and a fourth optical signal.

[0050] Some examples of the apparatus can include a second substrate that can be optically transmissive, the second substrate positioned proximate to or in contact with the second metamaterial level, wherein the first substrate, the first metamaterial level, the second substrate, and the second metamaterial level form a stack structure.

[0051] Some examples of the apparatus can include a spacer positioned adjacent to or in contact with the first substrate and the second substrate and forming a space between the first surface of the first substrate and the second surface of the second substrate, wherein the second metamaterial stage can be placed in the space created by the spacer.

[0052] Some examples of the apparatus can include a liquid optically transparent adhesive positioned in the space created by the spacer, wherein the second metamaterial stage can be positioned adjacent to or in contact with the second surface of the second substrate and the liquid optically transparent adhesive can be placed between the second metamaterial stage and the first surface of the first substrate.

[0053] Some examples of the apparatus can include a first reflector and a second reflector configured to reflect the first optical signal and the second optical signal, the first substrate positioned between the first reflector and the second reflector.

[0054] Some examples of the apparatus can include a cladding positioned between the first metamaterial stage and the first reflector, the thickness of the cladding configured to mitigate loss of optical signals interacting with the first metamaterial stage, or configured to protect the first metamaterial stage, or a combination thereof.

[0055] In some examples, the first metamaterial stage and the second metamaterial stage can be positioned adjacent to or in contact with the first reflector; or the first metamaterial stage can be positioned adjacent to or in contact with the first reflector and the second metamaterial stage can be positioned adjacent to or in contact with the second reflector.

[0056] In some examples, the first reflector forms a first aperture for receiving the first optical signal and the second optical signal, the second reflector forms a second aperture for outputting the third optical signal; or the first reflector forms a first aperture and a second aperture, the first aperture for receiving the first optical signal and the second optical signal, the second aperture for outputting the third optical signal.

[0057] In some examples, the first substrate, the first reflector, the second reflector, the first metamaterial stage, and the second metamaterial stage form a Fabry-Perot cavity configured to produce one or more resonant reflections of the first optical signal and the second optical signal.

[0058] In some examples, the first metamaterial stage can include operations, features, means, or instructions for shifting a phase profile of an optical signal based at least in part on one or more parameters of each metamaterial structure of a set of metamaterial structures arranged in a pattern.

[0059] In some examples, the one or more parameters of the set of metamaterial structures include a height of the metamaterial structures, a cross-sectional profile of the metamaterial structures, a diameter of the metamaterial structures, a dielectric property of the metamaterial structures, or any combination thereof.

[0060] In some examples, a total phase shift induced by the first set of metamaterial levels can be based on a phase shift profile of each metamaterial structure and a pattern of the set of metamaterial structures.

[0061] An apparatus can include a substrate that is optically transmissive and a set of metamaterial levels positioned adjacent to or in contact with the substrate and configured to: receive a first optical signal having a first mode and a second optical signal having a second mode over a first optical communication link, the first optical communication link including a multimode optical communication link; generate a third optical signal having a third mode from the first optical signal based at least in part on shifting a first phase profile of the first optical signal by the set of metamaterial levels; generate a fourth optical signal having a fourth mode from the second optical signal based at least in part on shifting a second phase profile of the second optical signal by the set of metamaterial levels; transmit the third optical signal having the third mode over a second optical communication link; and transmit the fourth optical signal having the fourth mode over a third optical communication link.

[0062] A method can include growing a substrate that is optically transmissive, depositing a metamaterial layer on the substrate, depositing a resist layer on the metamaterial layer, etching a portion of the resist layer to form a set of hardmasks, and etching the set of hardmasks and an exposed portion of the metamaterial layer based on etching the portion of the resist layer to form a set of metamaterial structures, wherein the set of metamaterial structures are configured to shift a first phase profile of a first optical signal having a first mode and a second phase profile of a second optical signal having a second mode to produce a third optical signal having a third mode and a fourth optical signal having a fourth mode.

[0063] An apparatus can include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions can be executable by the processor to cause the apparatus to grow a substrate that is optically transmissive, deposit a metamaterial layer on the substrate, deposit a resist layer on the metamaterial layer, etch a portion of the resist layer to form a set of hardmasks, and etch the set of hardmasks and an exposed portion of the metamaterial layer based on etching the portion of the resist layer to form a set of metamaterial structures, wherein the set of metamaterial structures are configured to shift a first phase profile of a first optical signal having a first mode and a second phase profile of a second optical signal having a second mode to produce a third optical signal having a third mode and a fourth optical signal having a fourth mode.

[0064] Another apparatus may include: a component for growing a light-transmitting substrate; a component for depositing a metamaterial layer on the substrate; a component for depositing a resist layer on the metamaterial layer; a component for etching a portion of the resist layer to form a set of hard masks; and a component for etching the set of hard masks and the exposed portion of the metamaterial layer based on the etching of the portion of the resist layer to form a set of metamaterial structures, wherein the set of metamaterial structures is configured to shift a first phase profile of a first optical signal having a first mode and a second phase profile of a second optical signal having a second mode to generate a third optical signal having a third mode and a fourth optical signal having a fourth mode.

[0065] A non-transitory computer-readable medium for storing code is described. The code may contain instructions executable by a processor to: grow a light-transmitting substrate; deposit a metamaterial layer on the substrate; deposit a resist layer on the metamaterial layer; etch a portion of the resist layer to form a set of hard masks; and based on the etched portion of the resist layer, etch the set of hard masks and the exposed portion of the metamaterial layer to form a set of metamaterial structures, wherein the set of metamaterial structures is configured to shift a first phase profile of a first optical signal having a first mode and a second phase profile of a second optical signal having a second mode to generate a third optical signal having a third mode and a fourth optical signal having a fourth mode.

[0066] The methods, apparatuses, and examples of non-transitory computer-readable media described herein may further include operations, features, components, or instructions for depositing reflective material based on etching exposed portions of the set of hard masks and metamaterial layers to form a reflector at one end of the set of metamaterial structures.

[0067] The methods, apparatus, and examples of non-transitory computer-readable media described herein may further include operations, features, components, or instructions for depositing a cladding layer on the set of metamaterial structures and on the exposed portions of the substrate based on etching the exposed portions of the set of hard masks and metamaterial layers, wherein the deposition of reflective material may be based on the deposition of the cladding layer.

[0068] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, reflective materials can be deposited on a cladding that may be located between this set of metamaterial structures and the reflective material.

[0069] In some examples of the methods, apparatus, and non-transient computer-readable media described herein, each metamaterial structure in this group may have one or more parameters, including the height of the metamaterial structure, the cross-sectional profile of the metamaterial structure, the diameter of the metamaterial structure, the dielectric properties of the metamaterial structure, or any combination thereof.

[0070] In some examples of the methods, apparatus, and non-transient computer-readable media described herein, at least some of the parameters of one or more metamaterial structures can be based on a second cross-sectional profile of an associated hard mask.

[0071] A method may include the following steps: depositing a light-transmitting substrate; depositing a resist layer on the substrate; etching a portion of the resist layer to form a set of cavities in the resist layer; depositing a metamaterial layer on the resist layer forming the set of cavities, the metamaterial layer filling at least some of the cavities in the set of cavities formed in the resist layer; etching the metamaterial layer and the resist layer based on the deposition of the metamaterial layer on the resist layer to form a set of metamaterial structures, wherein the set of metamaterial structures is configured to shift a first phase profile of a first optical signal having a first mode and a second phase profile of a second optical signal having a second mode to generate a third optical signal having a third mode and a fourth optical signal having a fourth mode.

[0072] An apparatus may include a processor, a memory in electronic communication with the processor, and instructions stored in the memory. The instructions are executable by the processor to cause the apparatus to: deposit a light-transmitting substrate; deposit a resist layer on the substrate; etch a portion of the resist layer to form a set of cavities in the resist layer; deposit a metamaterial layer on the resist layer forming the set of cavities, the metamaterial layer filling at least some of the cavities formed in the resist layer; and etch the metamaterial layer and the resist layer based on the deposition of the metamaterial layer on the resist layer to form a set of metamaterial structures, wherein the set of metamaterial structures is configured to shift a first phase profile of a first optical signal having a first mode and a second phase profile of a second optical signal having a second mode to generate a third optical signal having a third mode and a fourth optical signal having a fourth mode.

[0073] Another apparatus may include: a component for depositing a light-transmitting substrate; a component for depositing a resist layer on the substrate; a component for etching a portion of the resist layer to form a set of cavities in the resist layer; a component for depositing a metamaterial layer on the resist layer forming the set of cavities, the metamaterial layer filling at least some of the cavities formed in the resist layer; and a component for etching the metamaterial layer and the resist layer based on the deposition of the metamaterial layer on the resist layer to form a set of metamaterial structures, wherein the set of metamaterial structures is configured to shift a first phase profile of a first optical signal having a first mode and a second phase profile of a second optical signal having a second mode to generate a third optical signal having a third mode and a fourth optical signal having a fourth mode.

[0074] A non-transitory computer-readable medium for storing code is described. The code may contain instructions executable by a processor to: deposit a light-transmitting substrate; deposit a resist layer on the substrate; etch a portion of the resist layer to form a set of cavities in the resist layer; deposit a metamaterial layer on the resist layer forming the set of cavities, the metamaterial layer filling at least some of the cavities formed in the resist layer; and etch the metamaterial layer and the resist layer based on the deposition of the metamaterial layer on the resist layer to form a set of metamaterial structures, wherein the set of metamaterial structures is configured to shift a first phase profile of a first optical signal having a first mode and a second phase profile of a second optical signal having a second mode to generate a third optical signal having a third mode and a fourth optical signal having a fourth mode.

[0075] Examples of the methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, components, or instructions for depositing reflective materials based on etched metamaterial layers and resist layers to form a reflector at one end of this set of metamaterial structures.

[0076] The methods, apparatus, and non-transitory computer-readable media described herein may further include operations, features, components, or instructions for depositing a cladding layer on the metamaterial structure and on exposed portions of the substrate, based on an etched metamaterial layer and a resist layer, wherein the deposition of the reflective material may be based on the deposition of the cladding layer.

[0077] In some examples of the methods, apparatuses, and non-transient computer-readable media described herein, reflective materials can be deposited on a cladding that may be located between this set of metamaterial structures and the reflective material.

[0078] In some examples of the methods, apparatus, and non-transient computer-readable media described herein, each metamaterial structure in this group may have one or more parameters, including the height of the metamaterial structure, the cross-sectional profile of the metamaterial structure, the diameter of the metamaterial structure, the dielectric properties of the metamaterial structure, or any combination thereof.

[0079] In some examples of the methods, apparatus, and non-transient computer-readable media described herein, at least some of the parameters of one or more metamaterial structures may be based on the second cross-sectional profile of the associated cavity in the resist layer. Attached Figure Description

[0080] FIG. 1A An example illustrating a schematic diagram of an optical system according to the examples disclosed herein, the optical system supporting mode multiplexers or demultiplexers for fiber optic communications using metamaterials.

[0081] FIG. 1BExamples of diagrams are shown based on the examples disclosed herein, which can form at least a portion of a mode multiplexer or demultiplexer for optical fiber communication using metamaterials.

[0082] FIG. 1C An example diagram is shown of a decoupled multi-fiber optical communication link supported by a mode multiplexer or demultiplexer according to the examples disclosed herein, which uses metamaterials for optical fiber communication.

[0083] FIG. 1D An example diagram of a coupled multi-fiber optical communication link supporting a mode multiplexer or demultiplexer according to the examples disclosed herein, wherein the mode multiplexer or demultiplexer uses metamaterials for optical fiber communication.

[0084] FIG. 2A Examples of optical devices according to the examples disclosed herein are shown, which may form at least a portion of a mode multiplexer or demultiplexer for optical fiber communication using metamaterials.

[0085] FIG. 2B Examples of optical devices supporting mode multiplexers or demultiplexers according to the examples disclosed herein are shown, which use metamaterials for fiber optic communication.

[0086] FIG. 2C An example of the phase profile of an optical device supporting a mode multiplexer or demultiplexer according to the examples disclosed herein, the mode multiplexer or demultiplexer using metamaterials for fiber optic communication is shown.

[0087] FIG. 2D This illustrates the metamaterial utilized in an example of a mode multiplexer / demultiplexer, which uses the generated metamaterial. FIG. 2C Metamaterials with phase profiles.

[0088] FIG. 3 Examples of optical devices supporting mode multiplexers or demultiplexers according to the examples disclosed herein are shown, which use metamaterials for fiber optic communication.

[0089] FIG. 4A-4E Examples of optical devices supporting mode multiplexers or demultiplexers according to the examples disclosed herein are shown, which use metamaterials for fiber optic communication.

[0090] FIG. 5A-5F An example of a method for manufacturing an optical device according to the examples disclosed herein is shown, the optical device supporting mode multiplexers or demultiplexers for optical fiber communication using metamaterials. FIG. 5A-5FAn example of a method for manufacturing an optical device according to the examples disclosed herein is shown, the optical device supporting mode multiplexers or demultiplexers for optical fiber communication using metamaterials.

[0091] FIG. 6A-6F An example of a method for manufacturing an optical device according to the examples disclosed herein is shown, the optical device supporting mode multiplexers or demultiplexers for optical fiber communication using metamaterials.

[0092] FIG. 7 and FIG. 8 A flowchart is shown, illustrating one or more methods for supporting the use of metamaterials in mode multiplexers or demultiplexers for optical fiber communications, based on examples disclosed herein. Detailed Implementation

[0093] Optical communication systems are widely deployed to provide various types of communication content, such as voice content, video content, packet data, message sending and receiving, broadcast content, and so on. Optical communication systems rely on various types of modulation of the optical signals on a shared transmission fiber to increase the amount of information that can be transmitted over the fiber. Some types of modulation can include wavelength division multiplexing (WDM), polarization division multiplexing (PDM), frequency division multiplexing (FDM), time division multiplexing (TDM), space division multiplexing (SDM), and mode division multiplexing (MDM). An optical communication link can include one or more multimode fibers (MMF), one or more few-mode fibers (FMF), one or more single-mode fibers (SMF), one or more multi-core fibers (MCF), or any combination thereof.

[0094] An MCF (Multi-Cell Fiber) may be an example of an optical fiber containing multiple cores within a common cladding. An MCF can include multiple SMFs, multiple FMFs, multiple MMFs, or any combination thereof. For example, an MCF can include fibers of a single type (e.g., all SMFs) or fibers of different types (e.g., one SMF and three MMFs). Using an MCF, the core design, number of cores, core layout, cladding thickness (e.g., the minimum distance between the outer core center and the cladding-coating interface), cladding diameter, or any combination thereof can be designed to achieve the optical and mechanical performance of the MCF. The ideal fiber design may vary depending on the application. In some examples, an MCF may include a first core, a second core, a third core, and a fourth core. An MCF can contain any number of cores.

[0095] An MCF can be an example of a coupled or uncoupled MCF. Some MCFs may encounter problems related to inter-core crosstalk or other interference. An uncoupled MCF can be an MCF that assumes each individual core is an independent optical path. A coupled MCF can be an MCF in which one core is assumed to be at least partially dependent on another core. In some examples, the distance between at least some cores in an uncoupled MCF may be greater than the distance between at least some cores in a coupled MCF.

[0096] MDM technology can be used in short-range optical communication systems (e.g., connections within data centers) and long-range optical communication systems (e.g., connections between data centers, metropolitan environments, and submarine environments (e.g., transcontinental optical communication links)). By using multiple optical signals propagating in different guidance modes (FMF or MMF) (e.g., possible paths light takes in an optical fiber), the communication capacity of an optical communication link can be effectively increased. In such optical systems, mode multiplexers and mode demultiplexers can be used to perform MDM technology. For example, a multiplexer can combine optical signals propagating in SMF into (e.g.) optical signals propagating in different modes of FMF or MMF, while a demultiplexer can separate optical signals propagating in different modes of FMF or MMF into (e.g.) optical signals propagating in SMF. In other examples, multiplexers or demultiplexers can be used with an MCF to convert between different modes of different optical signals in different cores of the MCF.

[0097] Systems, apparatuses, and techniques for performing mode division multiplexing or demultiplexing using one or more metamaterials in optical communication systems are described. Optical devices can be configured to use one or more stages of the metamaterial to shift one or more phase profiles of an optical signal to a corresponding spatial mode of the multi- or demultiplexed optical signal. The optical device can be an example of a stacked design, in which two or more stages of metamaterial are stacked on top of each other. The optical device can also be an example of a folded design, in which the optical signal is reflected between different stages of the metamaterial.

[0098] Firstly, in reference FIG. 1A The features of this disclosure are described in the background content of the optical system described. (See reference...) FIG. 2A-8 The features of this disclosure are further described in the background content of the optical device, phase profile, and flowchart.

[0099] FIG. 1A An example illustrating a schematic diagram of an optical system 100 according to the examples disclosed herein is shown. The optical system 100 supports mode multiplexers or demultiplexers using metamaterials for fiber optic communication. The optical system 100 may include an optical communication link 105, a transmitter system 110, and a receiver system 115.

[0100] Optical system 100 can utilize MDM (Multiplication and Demultiplexing) technology to increase the amount of information communicated through a single optical communication link 105. MDM technology can include multiplexing a certain number of optical signals carried on a certain number of SMFs (Spatial Multiplexing Factors) to a smaller number of FMFs or MMFs (or vice versa) using different guidance modes of FMFs or MMFs. In some examples, such technology can enable bidirectional communication or capacity multiplication over a single optical fiber. In practice, MDM can convert an optical signal from a first mode in a first fiber to a second mode in a second fiber, where the first mode is different from the second mode. In some cases, MDM technology can convert an optical signal from a first mode in a first fiber to a first mode in a third fiber. In some cases, MDM technology can convert an optical signal from a first mode in a second fiber to a second mode in a third fiber, where the first mode is different from the second mode. Such conversions can be performed simultaneously by the same optical device. MDM technology can also include demultiplexing techniques that can demultiplex optical signals (e.g., a single optical signal) with different information in different spatial modes into more optical signals (e.g., two or more optical signals). MDM technology can increase the communication capacity of optical communication link 105.

[0101] Optical communication link 105 may be an example of an optical fiber used to transmit one or more optical signals. An optical fiber can transmit light from one end to the other through the principle of internal reflection. Information can be used to modulate one or more optical signals transmitted by optical communication link 105 to support communication between transmitter system 110 and receiver system 115. Optical communication link 105 may include one or more MMFs, one or more FMFs, one or more SMFs, or any combination thereof.

[0102] Transmitter system 110 can be configured to transmit optical signals via optical communication link 105. Transmitter system 110 may include a multiplexer 120 and one or more transmitters 125 that can be coupled using one or more optical communication links 130. Optical communication links 130 may include SMF, FMF, MMF, MCF, or any combination thereof. Transmitter 125 can be configured to transmit optical signals, including light energy operating at an optical wavelength (e.g., an optical band) and modulated by an information. In some cases, each transmitter 125 can be configured to transmit optical signals propagating using one or more guide modes. For example, each transmitter 125-a, 125-b, etc., can transmit optical signals downwards along an SMF. Transmitter system 110 can be an example of a system implemented at a central office (CO), front end, switching center, etc. In other examples, transmitter system 110 can be implemented at a consumer premises equipment (CPE) or other device.

[0103] Multiplexer 120 can be configured to multiplex several optical signals into one or more multimode optical signals, the multimode optical signals including multiple optical modes propagating using different modes of optical fiber. Multiplexer 120 can receive one or more optical signals from transmitter 125 (e.g., via one or more optical communication links 130) and can output one or more optical signals on optical communication links 105. Multiplexer 120 can be configured to implement MDM technology to convert a first mode of different optical signals into different second modes.

[0104] Receiver system 115 can be configured to receive optical signals transmitted via optical communication link 105. Receiver system 115 may include demultiplexer 135 and one or more receivers 140, wherein one or more receivers 140 may be coupled to demultiplexer 135 via one or more optical communication links 145. Optical communication link 145 may include SMF, FMF, MMF, MCF, or any combination thereof. Demultiplexer 135 can be configured to receive one or more optical signals propagating along optical communication link 105 in different modes and convert the optical signals into several single-mode optical signals. In some examples, demultiplexer 135 may receive optical signals transmitted via optical communication link 105 and may output one or more optical signals to receiver 140 (e.g., via one or more optical communication links 145). Demultiplexer 135 may be configured to implement MDM technology to convert different modes of optical signals into different modes.

[0105] Receiver 140 can be configured to receive optical signals, including light energy that operates at a light wavelength (e.g., an optical frequency band) and is modulated by an information. In some cases, each receiver 140 can be configured to receive optical signals propagating using one or more boot modes. For example, each receiver 140-a, 140-b, etc., can receive optical signals from an SMF. In some cases, receiver system 115 may be an example of a system implemented at a CO, front end, switching center, etc. In other examples, receiver system 115 may be implemented at a CPE or similar device.

[0106] Optical communication links 105, 130, and 145 can be examples of a wide variety of optical components known as waveguides, which utilize internal reflection (e.g., total internal reflection) to confine and guide light within a solid or liquid structure. Some optical fibers can use a structure called step-index fiber, which can have an inner core made of a material with a refractive index higher than the surrounding cladding. In an optical fiber, there exists a critical angle of incidence such that light is reflected from the core / cladding interface rather than refracted into the surrounding medium. For total internal reflection to occur within the fiber, the angle of incidence of light incident on the fiber must be smaller than a given angle.

[0107] Optical fibers can support more than one guiding mode. Each potential path through which light propagates in an optical fiber can be called a guiding mode of the fiber. The number of modes supported by an optical fiber may depend on the fiber's physical parameters (e.g., core / cladding region, refractive index, and wavelength of light). Examples of fiber types can include SMF (Superficial Multimode Fiber) supporting a single guiding mode, FMF (First Multimode Fiber) supporting a first number of modes, and MMF (Multifiber Multimode Fiber) supporting any number of modes. In some examples of multimode fibers, lower-order modes may spatially guide light closer to the fiber core (e.g., closer to the fiber's central axis), while higher-order modes may spatially guide light further away from the fiber core and fiber, and closer to the core / cladding interface. In some examples, one or more modes in the fiber may be examples of cladding modes, where the intensity distribution of light may substantially fill both the cladding and core regions. In some examples, one or more modes in the fiber may be examples of orbital angular momentum modes exhibiting a helical structure with respect to the fiber. In some examples, one or more modes in the fiber may be examples of resonator modes.

[0108] As described herein, MDM involves acquiring optical signals propagating in different spatial modes supported by one or more MMFs, one or more FMFs, one or more SMFs, or combinations thereof, and converting those optical signals into different spatial modes. For example, a mode multiplexer can receive multiple optical signals through an SMF and can convert the optical signals into different modes that can communicate along a single MMF or FMF fiber. In some examples, a mode demultiplexer can receive multiple optical signals propagating in different optical modes within a single MMF or FMF and can convert those optical signals into single-mode optical signals propagating down along individual SMFs. Other examples can include any type of FMF-FMF, FMF-MMF, MMF-FMF, or MMF-MMF mode conversion. Other examples of MDM can include multiplexing or demultiplexing between any number of SMFs, FMFs, or MMFs and any number of optical signals.

[0109] FIG. 1B An example of graph 160 is shown, illustrating a mode multiplexer or demultiplexer according to the examples disclosed herein, which uses metamaterials for fiber optic communication. Graph 160 may include plot 165, which shows the effective refractive index (n) of the optical fiber. eff This relates to how modes change within the same mode group and between different mode groups. The effective refractive index of an optical fiber can be based on the refractive index of the core and the refractive index of the cladding.

[0110] Figure 160 may also include depictions of different modes in the optical fiber. Figure 170 may show an optical fiber with a single mode. Figure 175 may show different mode configurations of an optical fiber with two modes. Figure 180 may show different mode configurations of an optical fiber with four modes. Figure 185 may show different mode configurations of an optical fiber with higher-order modes. An optical communication link or optical fiber may use illustrative modes, or any other mode or mode configuration, to transmit one or more optical signals, and such alternative modes or mode configurations are within the scope of this disclosure.

[0111] MDM technology can be used in short-distance optical communication systems (e.g., for connections within data centers) and long-distance optical communication systems (e.g., for connections between data centers, metropolitan environments, and submarine environments (e.g., transcontinental optical communication links)). By using multiple optical signals of different modes, the communication capacity of optical communication link 105 can be effectively increased. In such an MDM system, a mode multiplexer (e.g., a multiplexer) or a mode demultiplexer (e.g., a multiplexer), or both, can be used to perform MDM technology. For example, multiplexer 120 can convert optical signals of different modes (e.g., an SMF with a single-mode optical signal) from different input fibers into a single output fiber (e.g., an FMF or MMF with optical signals propagating in different modes in different fibers), and demultiplexer 135 can separate optical signals with multiple different modes from one input fiber (e.g., an FMF or MMF) into different output fibers (e.g., multiple SMFs).

[0112] To increase the capacity of optical communication systems, various multitasking and modulation techniques have been considered, utilizing various properties of light, including amplitude, phase, wavelength, and polarization. Space is considered a dimension in optical communication and can be used to increase the bandwidth of optical communication systems. In some cases, optical communication systems can use Space Division Multiplexing (SDM) technology. A first approach to implementing SDM may involve using multi-core fibers (coupled or uncoupled) to carry optical signals in multiple cores embedded in the same cladding. In such a method, the communication capacity can be equal to the combination of the number of fibers and the number of cores in each fiber. A second approach uses FMF or MMF to communicate optical signals in different modes of the fiber, such that the communication capacity can be correlated with (e.g., equal to) the combination of the number of fibers and the number of modes transmitted by each fiber.

[0113] When using SDM technology (including MDM technology), optical systems can implement multiplexing / demultiplexing techniques to convert optical signals between different types of optical fibers, different types of modes, different types of spatial configurations, or any combination thereof. For example, multiplexers and demultiplexers can be used to convert optical signals between SMFs and FMFs or MMFs, or to convert signals between FMFs or MMFs into different FMFs or MMFs. In some cases, mode multiplexers can use optical signals received from an SMF to excite a specific fiber mode in an FMF, while mode demultiplexers can separate different fiber modes in an FMF into different SMFs.

[0114] Some optical systems can perform MDM using one or more of several techniques. Examples of devices that can implement MDM can include free-space optical systems, directional coupler-based devices, or photonic lanterns, etc.

[0115] Free-space optical systems can include multiple optical components, such as lenses, mirrors, beam splitters, or phase plates, within a free-space setup. Such systems can be bulky and may require aligning and combining a number of optical components, potentially exhibiting high optical loss calibration based on the number of components.

[0116] Directional coupler-based devices can be configured to switch modes by controlling the coupling between adjacent waveguides or adjacent optical fibers. Such devices are typically sensitive to process errors, and the number of accessible modes may be space-limited.

[0117] A photonic lantern may include multiple SMFs at one end, an FMF at the other end, and a transition section in between. The number of accessible modes may also be limited by space, and due to the difficulty in manufacturing such a device, it may be difficult to scale this method to a large number of modes.

[0118] Optical system 100 can support systems, devices, and techniques for performing mode division multiplexing (MDM) or demultiplexing using one or more metamaterials. In some examples, the metamaterial can be or may include a metasurface. Devices with metamaterials can use one or more phase shields (e.g., high-resolution phase shields) enabled by the optical metamaterial to multitask or demultiplex modes of optical signals. The device can be an example of a stacked design where two or more levels of metamaterial overlap each other. The device can be an example of a folded design that reflects optical signals between different levels of the metamaterial. As further described herein, the phase profiles of the metamaterial levels in the device can be designed using adjoint analysis techniques (e.g., adjoint optimization techniques), wavefront matching techniques, or any combination thereof. Some fabrication methods used in MDM techniques may be difficult to scale (e.g., directional couplers or photonic lanterns) or may be lossy (e.g., free-space optical devices). In contrast, devices using metamaterials can be efficiently fabricated using a single photolithography step, regardless of the number of modes to be multitasked.

[0119] Mode multitasking and demultitasking are useful features in optical communication systems. An example of mode multitasking and demultitasking is a function that converts light propagating in an optical fiber in one or more modes into optical signals having one or more different modes, each of which is then included in a different output fiber.

[0120] Such functionality can be useful in a wide range of communication applications, such as long-distance communication networks employing MDM, access networks using multiple modes in downstream (e.g., from CO to CPE, as in Fiber to Local (FTTP) architectures or other network architectures) and upstream transmission (e.g., from CPE to CO in an FTTP network architecture), and data center applications. Each application may have different performance requirements, resulting in different specifications for mode multitasking and demultiplexing capabilities, such as multiple modes to multitask or demultiplex, optical performance specifications (e.g., insertion loss, crosstalk, channel bandwidth, channel spacing, or other or any combination thereof), environmental conditions, cost requirements, or density requirements. Specifically, in some data centers and certain access applications, density requirements related to containing more optical signals in a smaller volume are becoming increasingly important.

[0121] The implementation of spatial mode multiplexers or demultiplexers can be based on free-space optics, which can utilize multiplane optical conversion methods. This approach uses a series of phase plates and optical Fourier transforms to modify the wavefront of the light field. One advantage of free-space optical methods is their scalability to a large number of modes. A disadvantage is their use of micro-optical components, including collimating lenses, mirrors, and phase plates, which may require precise mechanical alignment and integration of these components, increasing cost and limiting device size. Another drawback is that the phase plates used in current devices may have relatively low spatial resolution (approximately 10 µm), potentially leading to a relatively large number of phase plates required for mode multitasking and again resulting in bulky devices. Other approaches can include devices using directional couplers and photonic devices, which can convert modes by controlling the coupling between adjacent waveguides and photonic lanterns. Such devices can be bulky, sensitive to fabrication errors, and difficult to scale to a large number of modes or any combination thereof.

[0122] In some examples, such as server architecture fiber optics, mode multiplexers or mode demultiplexers can be used for hundreds of fibers, and devices with small form factors can therefore be useful in such applications. Multiplexers and demultiplexers that perform MDM using metamaterials can exhibit highly compact form factors. Such size differences allow metamaterial devices to be integrated into optical connectors.

[0123] In some examples, the fabrication process for metamaterial-based optical devices can be relatively simple compared to other MDM devices. For instance, commercial spatial light modulators (SLMs) or multilayer silicon dioxide substrates may require iterative photolithography and multilayer etching to form a phase plate. In some cases, metamaterials can be fabricated using a single photolithography step or nanoimprint technology. This fabrication simplicity can improve the yield of such devices and reduce their cost compared to other devices that use more complex fabrication techniques.

[0124] In some examples, metamaterial-based optical devices can be monolithically integrated, and a single layer of metamaterial (e.g., decomposed into multiple levels) can be used to perform mode multitasking and demultitasking. Such features can produce a device with a smaller footprint than other devices and that does not require complex packaging, further reducing manufacturing and assembly costs. In some cases, the sole alignment application of metamaterial-based optical devices may be for aligning input and output fibers.

[0125] Compared to SLM and multilayer silica devices, metamaterial-based optical devices may have higher spatial resolution (smaller than wavelength). Such spatial resolution allows metamaterial-based optical devices to better control the wavefront, meaning that similar device performance can be achieved with fewer phase plates, thereby further reducing size and potentially reducing optical loss due to less reflection.

[0126] In some examples, metamaterial-based optical devices utilizing the principle of reflection can be used in folded designs, or resonant folded designs can exhibit high transmission efficiency. In some examples, the design of phase profiles using adjoint analysis methods (e.g., adjoint optimization techniques) can allow additional degrees of freedom to tune the device's performance (e.g., mode-dependent loss compensation). In some examples, metamaterials can be configured to be polarization-insensitive, so that metamaterial-based multiplexers / demultiplexers do not interfere with polarization multitasking. Note that the terms metamaterial and metasurface described herein can refer to materials whose properties are based on their intrinsic structure (e.g., geometry, arrangement, size, shape, orientation, etc.) and can be configured for a variety of purposes, applications, or technologies.

[0127] FIG. 1C Figure 190 illustrates an example of a decoupled multi-fiber optical communication link 191 supporting a wavelength multiplexer or demultiplexer according to the examples disclosed herein, where the mode multiplexer or demultiplexer uses metamaterials for fiber optic communication. The uncoupled multi-fiber optical communication link 191 can be as shown in reference... FIG. 1A Examples of optical communication links 105, 130, and 145 are described.

[0128] An MCF may be an example of an optical fiber containing multiple cores within a common cladding. An MCF may include multiple SMFs, multiple FMFs, multiple MMFs, or any combination thereof. For example, an uncoupled multi-core optical communication link 191 may include a first core 192-a, a second core 192-b, a third core 192-c, and a fourth core 192-d, and a cladding 193 located near each core 192 (e.g., close to, adjacent to, without one or more materials between them, or with one or more materials between them) or in contact with each core 192. The cores 192 of the uncoupled multi-core optical communication link 191 may be examples of SMFs, FMFs, MMFs, or any combination thereof. Depending on the situation, the MCF may include fibers of a single type (e.g., all SMFs) or may include fibers of different types (e.g., one SMF and three MMFs). Using MCFs, the core design, number of cores, core layout, cladding thickness (e.g., the minimum distance between the outer core center and the cladding-coating interface), cladding diameter, or any combination thereof, can be designed to achieve the optical and mechanical performance of the MCF. The ideal fiber design may vary depending on the application. MCFs can include any number of cores (e.g., two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, etc.).

[0129] An MCF can be an example of a coupled or uncoupled MCF. Some MCFs may encounter problems related to inter-core crosstalk or other interference. An uncoupled MCF can be an MCF that assumes each individual core is an independent optical path. A coupled MCF can be an MCF in which one core is assumed to be at least partially dependent on another core. In some examples, the distance between at least some cores in an uncoupled MCF may be greater than the distance between at least some cores in a coupled MCF.

[0130] The uncoupled multi-fiber optical communication link 191 may be an example of an uncoupled MCF. In some cases, the parameters of the different fibers 192 may be the same. In other examples, at least one of the multiple fibers 192 may have parameters different from the others. Examples of the parameters of the fibers 192 may include the diameter of the fibers, the dielectric properties of the fibers, the relative difference between the dielectric properties of the fibers 192 and the dielectric properties of the cladding 193, the distance from the center of the fibers to the center of the uncoupled multi-fiber optical communication link 191, the modulus of the fibers, the refractive index profile (e.g., Δn), or combinations thereof. In some examples, the diameter of each fiber 192 may be approximately 8.2 micrometers, the refractive index profile of the fibers 192 may be approximately 0.35% (e.g., Δn = 0.35%), and the center-to-center distance of the fibers may be approximately 45 micrometers.

[0131] Figure 190-a shows the intensity distribution of the optical signal in the first fiber core 192-a, where other fiber cores (e.g., cores 192-b, 192-c, and 192-d) do not transmit optical signals. Figure 190-b shows the intensity distribution of the optical signal in the second fiber core 192-b, where other fiber cores (e.g., cores 192-a, 192-c, and 192-d) do not transmit optical signals. Figure 190-c shows the intensity distribution of the optical signal in the third fiber core 192-c, where other fiber cores (e.g., cores 192-a, 192-b, and 192-d) do not transmit optical signals. Figure 190-d shows the intensity distribution of the optical signal in the fourth fiber core 192-d, where other fiber cores (e.g., cores 192-a, 192-b, and 192-c) do not transmit optical signals.

[0132] In some specific embodiments, the coupled optical communication link 195 may include one or more multi-core or multimode optical fibers. FIG. 1D Figure 195 illustrates an example of a coupled multi-fiber optical communication link 196 supporting a mode multiplexer or demultiplexer according to the examples disclosed herein, wherein the mode multiplexer or demultiplexer uses metamaterials for optical fiber communication. The coupled multi-fiber optical communication link 196 can be as shown in reference... FIG. 1A Examples of optical communication links 105, 130, and 145 are described.

[0133] The coupled multi-fiber optical communication link 196 may include multi-fiber optical fibers. For example, it may include a first fiber core 197-a, a second fiber core 197-b, a third fiber core 197-c, and a fourth fiber core 197-d, as well as a cladding 198 positioned adjacent to or in contact with each fiber core 197. The fiber cores 197 of the coupled multi-fiber optical communication link 196 may be examples of SMF, FMF, MMF, or any combination thereof. In some cases, the MMF may include fibers of a single type (e.g., all SMFs) or fibers of different types (e.g., one SMF and three MMFs).

[0134] The coupled multi-fiber optical communication link 196 can be an example of a coupled MCF. In some cases, the parameters of the different fibers 197 can be the same. In other examples, at least one of the multiple fibers 197 can have parameters different from the others. Examples of the parameters of the fibers 197 can include the diameter of the fiber, the dielectric properties of the fiber, the relative difference between the dielectric properties of the fiber 197 and the dielectric properties of the cladding 198, the distance from the center of the fiber to the center of the uncoupled multi-fiber optical communication link 196, the modulus of the fiber, the refractive index profile (e.g., Δn), or combinations thereof. In some examples, the diameter of each fiber 197 can be approximately 8.2 micrometers, the refractive index profile of the fiber 197 can be approximately 0.35% (e.g., Δn = 0.35%), and the center-to-center distance of the fibers can be approximately 20 micrometers.

[0135] Figures 195 (e.g., Figure 195-a, Figure 195-b, Figure 195-c, ​​and Figure 195-d) illustrate the different intensity distributions of optical signals in different fiber cores 197. In Figure 195-a, the distribution in each fiber core 197 can be approximately the same. In Figure 195-b, the second fiber core 197-b can have a strong distribution at the center (e.g., around 0.9), the third fiber core 197-b can have a strong distribution at the center (e.g., around -0.9), the fourth fiber core 197-d can have a moderate distribution at the center (e.g., around -0.5), while the first fiber core 197-a can have a moderate distribution at the center (e.g., around 0.5). In Figure 195-c, ​​the fourth core 197-d may have a strong distribution at the center (e.g., around 0.9), the first core 197-a may have a strong distribution at the center (e.g., around -0.9), the third core 197-c may have a moderate distribution at the center (e.g., around -0.5), and the second core 197-b may have a moderate distribution at the center (e.g., around 0.5). In Figure 195-d, the first core 197-a may have a strong distribution at the center (e.g., around -0.9), the second core 197-b may have a strong distribution at the center (e.g., around 0.9), the third core 197-c may have a strong distribution at the center (e.g., around 0.9), and the fourth core 197-d may have a strong distribution at the center (e.g., around -0.9).

[0136] FIG. 2A An example of an optical device 201 according to the examples disclosed herein is shown. Optical device 201 can form at least part of a mode multiplexer or demultiplexer for fiber optic communication using metamaterials. Optical device 201 can be an example of a multiplexer / demultiplexer device using metamaterials, as shown in reference... FIG. 1AAs described above. In some cases, the optical device 201 may be an example of a mode multiplexer / demultiplexer device.

[0137] Optical device 201 may include a substrate 205 and multiple metamaterial structures 210. In some cases, optical device 201 may also include a cladding (not shown). In some cases, the cladding may be air or other ambient gas surrounding the metamaterial. The metamaterial (sometimes called a metasurface) may be a nanophotonic structure that can control the properties of light (e.g., the phase or direction of light propagation) passing through the metamaterial at a relatively high spatial resolution (e.g., subwavelength, depending on the operating wavelength window, approximately several hundred nanometers). In some examples, each (or at least some) metamaterial structure 210 may have one or more parameters that affect how the properties of light change as light passes through the metamaterial structure 210. Arrays of metamaterial structures 210 may be patterned (thus forming a metamaterial level) to produce a desired shift in the properties of the optical signal when the optical signal interacts with the metamaterial level. The phase profile and nanostructure of the metamaterial can be configured to control the spatial profile of light, and thus can be used for fiber-mode multitasking and demultitasking applications. High spatial resolution and the ability to perform multiple optical functions in a single stage of a metamaterial or a single metamaterial structure, among other examples, could lead to small devices that can be monolithically integrated on a single substrate. A simple manufacturing process could reduce the overall loss and packaging complexity of such multiplexers or demultiplexers.

[0138] In some contexts, metamaterials may refer to a class of materials that possess properties not found in naturally occurring materials. Optical metamaterials can be smaller than the wavelength of light, but can still interact with and influence light. Examples of interactions between metamaterials and light can include negative refraction, fast and slow light propagation at zero refractive index, notch filters, plane lenses, thin lenses, perfect lenses, or any combination thereof.

[0139] Individual metamaterial structures 210 can influence light passing through them based on one or more properties of the metamaterial structure 210. Examples of properties of the metamaterial structure 210 that can influence light may include the height of the metamaterial structure (e.g., the dimension of the metamaterial structure 210 extending away from the substrate 205), the cross-sectional profile of the metamaterial structure 210 (e.g., the cross-sectional shape of the metamaterial), the cross-sectional area of ​​the metamaterial structure 210, the volume of the metamaterial structure 210, the diameter of the metamaterial structure 210, the dielectric properties of the metamaterial structure 210, the relative difference between the dielectric properties of the metamaterial structure 210 and the dielectric properties of the substrate 205, the relative difference between the dielectric properties of the metamaterial structure 210 and the dielectric properties of the cladding, or any combination thereof. In some cases, the metamaterial structure 210 may be an example of a multilayer metamaterial structure, wherein a first metamaterial structure having a first set of parameters is stacked on top of a second metamaterial structure 210 having a second set of parameters. Multilayer metamaterial structures may include any number of metamaterial structures. In some cases, different metamaterial structures in the stack may have different dielectric properties or other properties.

[0140] FIG. 2A The illustrated metamaterial structure 210 shows examples of metamaterial structures with circular, rectangular, and hexagonal cross-sectional shapes, different cross-sectional areas, and different heights. These illustrative metamaterial structures 210 are merely examples of some properties of metamaterial structures. For example, in some cases, the metamaterial structure 210 can have any cross-sectional profile, such as circular, triangular, square, rectangular, pentagonal, hexagonal, other geometric cross-sectional profiles, other shapes, or any combination thereof. FIG. 2A As shown, each metamaterial structure 210 may correspond to a unit cell 212 of a set of unit cells for a metamaterial structure level. Additionally or alternatively, the unit cell 212 of a set of unit cells for a metamaterial structure level may include two or more metamaterial structures 210. In some examples, metamaterial structures 210 may have one or more identical parameters and may have one or more different parameters. For example, in some cases, all metamaterial structures 210 may have the same cross-sectional shape (e.g., circular) but may have different cross-sectional shapes (e.g., different dimensions, different diameters). For example, in some cases, all metamaterial structures 210 may have the same height (e.g., relative to the substrate) but may have different cross-sectional areas (e.g., different dimensions, different diameters). In some examples, one or more parameters associated with a set or subset of metamaterial structures 210 may be the same or may be different.

[0141] The substrate 205 may be an example of a material used to form a support substrate for optical components (e.g., metamaterials), other components, or any combination thereof. In some cases, the metamaterial structure 210 is coupled to the substrate 205. In some cases, the substrate 205 may be optically transmissive, allowing optical signals to pass through it.

[0142] Each individual metamaterial structure 210 can be relatively small. To shift the phase profile of an optical signal, multiple metamaterial structures 210 can be arranged in a pattern and configured to shift the phase profile of the optical signal. An array or pattern of metamaterial structures 210 may be referred to as a metamaterial structure level. Each individual metamaterial structure 210 can have its own set of parameters affecting light. The overall phase-shift profile of the metamaterial level can be based on the parameters of each individual metamaterial structure 210 in this level. In some cases, a cladding can be positioned close to or in contact with the metamaterial structure 210, the substrate 205, or any combination thereof. The cladding can be configured to mitigate the loss of optical signals interacting with the metamaterial structure 210, or to protect the metamaterial structure 210 from damage, or any combination thereof. In some cases, the metamaterial structure 210 may be an example of a reflective metamaterial structure and can be configured to be achromatic or highly dispersive.

[0143] Each metamaterial structure 210 is shown as a separate, independent structure. In some examples, at least some or all of the metamaterial structures 210 may be formed from a single, larger region. In such examples, a unit cell may refer to a single configurable portion of a larger region of the metamaterial, which can be modified to achieve a desired phase profile.

[0144] FIG. 2B An example of an optical device 202 according to the examples disclosed herein is shown. Optical device 202 can form at least a portion of a mode multiplexer or demultiplexer for optical fiber communication using metamaterials. Optical device 202 can be an example of a multiplexer / demultiplexer device using metamaterials, as described with reference to Figures 1 and 2A. In some cases, optical device 202 can be an example of a mode multiplexer / demultiplexer device.

[0145] Optical device 202 may include a substrate 205, a plurality of metamaterial structures 210, a cladding 215 surrounding the metamaterial structures 210, and a reflector 220. Optical device 202 may be an example of a metamaterial level using a reflective design. In such a design, light can pass through the metamaterial structure 210, be reflected by the reflector 220, and then pass through the metamaterial structure 210 again after being reflected. In such a design, the phase profile of the metamaterial level may be based on both the phase shift caused by the light that first (e.g., initially) passes through the metamaterial structure 210 and the phase shift caused by the reflected light that passes through the metamaterial structure 210. (See reference...)FIG. 2A The features of substrate 205 and metamaterial structure 210 are described and are incorporated herein by reference.

[0146] Cladding 215 may be a material layer. In some cases, cladding 215 may have a lower refractive index than metamaterial structure 210. In some cases, cladding 215 may be configured to mitigate the loss of optical signals interacting with metamaterial structure 210. In some cases, cladding 215 may be configured to protect metamaterial structure 210 from damage.

[0147] In some examples, the cladding 215 may be located between the surface 225 of the metamaterial structure 210 and the reflector 220. In such examples, a distance 230 may be formed between the surface 225 of the metamaterial structure 210 and the surface 235 of the reflector 220. The distance 230 may be configured to mitigate the loss of optical signals passing through the metamaterial structure 210 and reflected by the reflector 220. In some cases, the distance 230 may be approximately 500 nanometers. In some cases, the distance 230 may be between zero nanometers and several micrometers (e.g., one, two, or three micrometers). The surface 225 of the metamaterial structure 210 may be opposite to a different surface of the metamaterial structure 210 that is in contact with the substrate 205.

[0148] Reflector 220 may be formed of one or more reflective materials. Examples of reflective materials may include gold or another metal. In some cases, the reflective material may be coated with another material to help reflect light. FIG. 2B The light field is shown as perpendicular to the metamaterial structure 210, substrate 205, cladding 215, and / or reflector 220. In some examples, the light field may arrive and / or depart at an angle not perpendicular to the metamaterial structure 210, substrate 205, cladding 215, and / or reflector 220.

[0149] Each metamaterial structure 210 is shown as a separate, independent structure. In some examples, at least some or all of the metamaterial structures 210 may be formed from a single, larger region. In such examples, a unit cell may refer to a single configurable portion of a larger region of the metamaterial, which can be modified to achieve a desired phase profile.

[0150] FIG. 2C An example of a phase profile 203 of an optical device supporting a mode multiplexer or demultiplexer, according to the examples disclosed herein, is shown. The mode multiplexer or demultiplexer uses metamaterials for fiber optic communication. The shading of the phase profile 203 can indicate different phase shifts caused by different parts of the optical device (e.g., optical device 201 or 202). As described herein, the phase profile 203 can be an example of a phase profile designed using wavefront matching techniques or adjoint analysis (e.g., adjoint optimization).

[0151] Multiple metamaterial structures can be patterned and configured to shift the phase profile of an optical signal. An array or pattern of metamaterial structures can be called a metamaterial structure level. Each metamaterial structure in a level of metamaterial components can be configured to shift a portion of the phase of an optical signal. In some cases, a single metamaterial structure can be considered a single pixel (or unit cell) of a larger metamaterial level. In some cases, the size of the metamaterial structure depends on the operating wavelength window (e.g., a unit cell size of 500 nm x 500 nm when the operating wavelength is 1550 nm) and can be on the order of hundreds of nanometers. The overall phase shift performed by the metamaterial level can be based on the combination of each individual phase shift performed by each individual metamaterial structure in the metamaterial structure level. By varying the parameters of individual metamaterial structures within the metamaterial level, the metamaterial level can be designed to have different phase profiles. In some examples, light is transmitted through a substrate and the metamaterial structure (e.g., a metamaterial pillar with a length or height l), and the phase transition in each unit cell is determined by the geometry of the structure (e.g., cross-sectional profile, cross-sectional area, height, etc.). In some cases, metamaterial structures can have anisotropic geometries that can produce a birefringent response to spatially control the polarization of light. In some cases, cladding (using transparent materials) can be added to encapsulate the pillars and protect the structure. Metamaterial structures (or metamaterial elements) can be arranged in arrays of hundreds, thousands, and in some exemplary embodiments, millions of metamaterial structures. Metamaterial structures or metamaterial elements can be pillars, and their centers (or peaks) are spaced less than 2 micrometers apart, preferably less than 1 micrometer for an operating wavelength of about 1500 nm. In some embodiments, metamaterial structures or their centers or peaks are spaced 200 nm to 750 nm apart, for example, about 500 nm. Continuous geometries of metamaterial structures or metamaterial elements are possible, but the peaks of metamaterial structures or metamaterial elements are preferably spaced at least 100 nm apart.

[0152] Phase profile 203 is an example of a phase profile caused by one or more levels of a metamaterial. Based on the parameters of various metamaterial structures forming the metamaterial levels, the metamaterial levels can have different phase profiles. In some cases, the wavelength-dependent behavior of the phase (or dispersion) can be tuned so that the metamaterial device can be achromatic or have relatively high dispersion. Furthermore, the metamaterial structure can be designed to operate in a reflection mode when light passes through the pillar and is reflected back by one or more reflective materials (e.g., metal). For example, this can be achieved through… FIG. 2D The metamaterial structure 210 shown (in these specific embodiments, multiple pillars) is used to generate FIG. 2C The phase profile shown.

[0153] Depending on the operating wavelength window, different materials can be selected for the substrate and metamaterial structure. For example, for the O-band (1260–1360 nm), C-band (1530–1565 nm), or L-band (1565–1625 nm) windows, crystalline silicon, amorphous silicon, silicon nitride (Si3N4), and chalcogenide glasses can be used for the metamaterial structure. For shorter wavelength windows (e.g., 850–940 nm), other materials (e.g., titanium oxide (TiO2) and silicon nitride (Si3N4)) can be used for the metamaterial structure. Transparent materials such as glass or polymers (e.g., SU8) can be used for the substrate and cladding.

[0154] In some cases, different design techniques can be used to design metamaterial-level phase profiles. Examples of design techniques can include wavefront matching, adjoint analysis, or any combination thereof.

[0155] Mode multitasking and demultitasking in optical fibers can be achieved by modifying the wavefront of the optical field using a series of phase plates (e.g., metamaterial-level) and free-space propagation. To achieve low-loss and low-crosstalk mode multitasking or mode demultitasking, multi-level metamaterials (whether stacked or folded designs) can be used. The phase profiles of each level of the metamaterial for mode multitasking or mode demultitasking can be designed using various methods, including wavefront matching, adjoint analysis, or any combination thereof.

[0156] In wavefront matching methods, the forward-propagating input field is compared with the backward-propagating target field to obtain the field difference for each stage of the metamaterial. This difference can be compensated for by designing the stages of the material phase plates, resulting in precise field matching. Such steps can be performed iteratively to achieve the design. Based on the analysis using wavefront matching methods, metamaterial stages can be designed with phase profiles that produce devices with low loss and low crosstalk performance.

[0157] In adjoint analysis methods (e.g., adjoint optimization methods), the design quality factor (FOM) can be defined as the power throughput for each individual input-output pair. Given the FOM, its derivative with respect to each design parameter can be calculated. In some cases, the derivative of the FOM can be calculated based on the propagation field at each metamaterial structure. Given the derivative, efficient gradient-based nonlinear enhancement routines (e.g., conjugate gradient (CG), Newton CG, sequential least squares programming (SLSQP), Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm, etc.) can be used to search for enhanced phase profiles. Depending on the application, additional FOMs can be efficiently added (e.g., when they can be written as analytical expressions for design variables or field variables). For example, to reduce the complexity of phase masking, a FOM term corresponding to the average difference in phase values ​​between each pair of adjacent pixels (or cells) can be added to the analysis. In other examples, instead of enhancing the average loss across all channels, the worst-case (maximum) loss across all channels can be minimized, or the loss based on a specific distribution (e.g., channel bandwidth) can be enhanced.

[0158] FIG. 3 An example of an optical device 300 supporting a mode multiplexer or demultiplexer according to the examples disclosed herein is shown. The mode multiplexer or demultiplexer uses metamaterials for fiber optic communication. The optical device 300 can perform mode multitasking or mode demultiplexing techniques using optical metamaterial structures and optical substrates stacked on top of each other. The optical device 300 can be a reference. FIG. 2A An example of the optical device 201 described. FIG. 3 The diagram shown may be a cross-sectional view of the optical device 300.

[0159] Optical device 300 may include multiple substrates 305 positioned close to or in contact with multiple stages 310 of a metamaterial. Each stage 310 of the metamaterial may include multiple metamaterial structures. The multiple substrates 305 and the multiple stages 310 may be stacked on top of each other. Optical device 300 may also include one or more spacers 315 and one or more optically transparent adhesives (OCAs) 320 located between each layer of substrate 305 and the metamaterial stage 310. Optical device 300 may include any number of metamaterial layers to perform mode multitasking or mode demultitasking techniques. For example, optical device may include a first stage 310-a, a second stage 310-b, a third stage 310-c, or any number of stages 310-N. In such an example, optical device 300 may include any number of substrates 305, spacers 315, and OCAs 320 to support platform 310. In some examples, the number of substrates 305 may be the same as the number of metamaterial stages 310. The number of layers may be determined based on the desired phase profile of optical device 300.

[0160] Substrate 305 may be a light-transmitting substrate configured to support metamaterial grade 310. Substrate 305 may have one or more parameters defining the structure, such as height (h). Substrate 305 may be a reference. FIG. 2A-2B An example of substrate 205 is described. Substrate 305 may be a reference. FIG. 2A-2B Examples of substrate 205 described. In some examples, each substrate 305 in the optical device 300 may have the same parameters. Alternatively, based on the desired phase profile of the optical device 300, one or more substrates 305 may have parameters different from those of the other substrates in the optical device 300 (e.g., the height (h) of one or more substrates 305 may be different).

[0161] Metamaterial stage 310 may include one or more transmissive metamaterial structures configured to shift the phase profile of an optical signal (e.g., light) passing through the metamaterial structure. Each stage 310 of the metamaterial may be positioned in proximity to or in contact with at least one substrate 305. The metamaterial structure of stage 310 may be a reference. FIG. 2A-2B Examples of described metamaterial structures 210 are given. In other examples, the metamaterial structure of metamaterial level 310 may have one or more parameters defining the metamaterial structure, such as cross-sectional profile, cross-sectional area, or height, etc. In some examples, each level 310 of the metamaterial may be designed to have a different phase profile, and the combined phase profile of each level 310 may produce the overall phase profile of the optical device 300. In some examples, based on the desired phase profile of the optical device 300, one or more levels 310 of the metamaterial may have parameters different from those of other levels 310 of the metamaterial in the optical device 300. In some examples, each level 310 of the metamaterial in the optical device 300 may have the same parameters.

[0162] Spacers 315 can be located between two different substrates 305 and can be configured to create a space 325 between the different substrates 305. Spacers 315 can be positioned close to or in contact with the first substrate 305 and the second substrate 305 to create the space 325. Metamaterial grade 310 can be placed in the space 325 created by the spacers 315. Spacers 315 can have one or more parameters defining the structure, such as height. In some examples, each spacer 315 in the optical device 300 can have the same parameters. In some examples, one or more spacers 315 can have parameters different from other spacers 315 in the optical device 300 (e.g., the heights of one or more spacers 315 can be different). Any number of spacers 315 can be located between different substrates.

[0163] OCA 320 can be positioned within a space 325 created by spacer 315. OCA 320 can be an example of liquid OCA or gel OCA or any combination thereof. OCA 320 can be a light-transmitting material. OCA 320 can be configured to protect metamaterial level 310. OCA 320 can be positioned such that metamaterial level 310 is positioned close to or in contact with the surface of substrate 305, and is also positioned close to or in contact with OCA 320. In such an example, OCA 320 can be positioned between one or more surfaces of metamaterial level 310 and the bottom surface of substrate 305. For example, OCA 320 can be located between one or more surfaces of the metamaterial structure of second level 310-b of metamaterial and the bottom surface of substrate 305. In some cases, OCA 320 can be an example of a refractive index-matching material, wherein the refractive index of OCA 320 can be similar to the refractive index of one or more surrounding materials.

[0164] Optical device 300 can be configured as a mode multiplexer. In some cases, optical device 300 can be configured as a mode demultiplexer. In this case, the input and output of optical device 300 can be reversed. Input fiber 330 can be positioned at a first distance (d1) from the first stage 310-a of the metamaterial and can be configured to transmit one or more optical signals through optical device 300. Input fiber 330 can be a reference. FIG. 1A Examples of optical communication links 105, 130, or 145 are described. The output fiber 335 can be positioned at a second distance (d2) from the last layer (e.g., the last substrate 305) of the optical device 300 and can be configured to receive one or more optical signals output from the optical device 300. FIG. 1AExamples of optical communication links 105, 130, or 145 are described. In some cases, the input fiber 330, output fiber 335, or any combination thereof may be examples of an optical fiber array having multiple fibers. In some cases, the first distance (d1) may be the same as the second distance (d2). In some cases, the first distance (d1) may be different from the second distance (d2). In some cases, the input fiber 330 may include one or more SMFs, and one or more input signals may be single-mode input signals. In other examples, the input fiber 330 may include one or more FMFs or MMFs, and at least one input signal may be a multimode signal. Additionally or alternatively, the output fiber 335 may include one or more SMFs, and one or more output signals may be single-mode output signals. In other examples, the output fiber 335 may include one or more FMFs or MMFs, and at least one input signal may be a multimode signal. In some cases, additional spacers, additional OCAs, or combinations thereof may be located between the input fiber 330 and the first stage 310-a of the metamaterial. In some cases, additional spacers, additional OCAs, or combinations thereof may be located between the output fiber 335 and the last layer of the optical device 300 (e.g., the last substrate 305). Such additional spacers or additional OCAs may be configured to reduce back reflection, protect metamaterials, or provide spacing between the fiber and the optical device, or any combination thereof.

[0165] In an example where the optical device 300 is configured as a mode multiplexer, the input fiber 330 may be an example of a fiber array, and two or more optical signals with different modes or multiple versions of the same mode can be transmitted into the optical device 300. The two or more optical signals can pass through different stages 310 of the metamaterial (and other components) of the optical device 300. At each stage 310, the phase profiles of the two or more optical signals can be shifted or altered. Through the different stages 310, the optical device 300 can convert the two or more optical signals into different optical signals propagating along different modes of the FMF or MMF. The output fiber 335 may be an example of a single output fiber and can be configured to receive optical signals propagating along different guiding modes.

[0166] In an example where the optical device 300 is configured as a mode demultiplexer, the input fiber 330 may be a single fiber, and optical signals propagating in different modes can be transmitted along this single fiber into the optical device 300. The optical signals can pass through different stages 310 of the metamaterials (and other components) of the optical device 300. At each stage 310, the phase profile of the optical signal can be shifted or altered. Through the different stages 310, the optical device 300 can convert the optical signal into two or more different optical signals with different modes (e.g., multiple optical signals propagating along the SMF). The output fiber 335 may be an example of a fiber array, and can be configured to receive two or more optical signals that have been demultiplexed from the original optical signal.

[0167] In certain cases, the optical device 300 can be used in SDM / MDM applications. The optical device 300 can coherently shape the modes of light, for example, from one mode to another. Light in the first stage of the metamaterial can propagate in many directions and may interfere with each other as it propagates to or over the second stage of the metamaterial. Light in the second stage of the metamaterial can propagate in multiple directions, and these lights may interfere with each other as they propagate to or through the third stage of the metamaterial. The spacer 315 can be configured to allow light propagating between the metamaterial stages 310 to interfere with each other.

[0168] FIG. 4A-4E Examples of optical devices supporting mode multiplexers or demultiplexers according to the examples disclosed herein are shown, which use metamaterials for fiber optic communication. FIG. 4A-4E The optical device shown can be an example of a folded design for an optical device that uses reflective surfaces to transmit light between different levels of a metamaterial. FIG. 4A-4E The optical device shown may be a reference FIG. 2B An example of the optical device 202 described. FIG. 4A-4E Various configurations of folded designs for optical devices used as mode multiplexers or mode demultiplexers are shown. This disclosure is not limited to the illustrated fast optical device configurations. FIG. 4A-4E Any feature of any optical device configuration shown can be associated with FIG. 4A-4E Any other combination of features in any optical device configuration shown. First refer to... FIG. 4A Describe various aspects of the optical device, but FIG. 4B-4E Explanations for them have been omitted. FIG. 4A-4E In optical devices, features with similar numbers or similar implementations can be handled similarly. FIG. 4A-4E An optical device with four metamaterial levels is shown. However, FIG. 4A-4EThe optical devices can be configured with any number of metamaterial levels (e.g., one level, two levels, three levels, four levels, five levels, six levels, seven levels, eight levels, nine levels, etc.). FIG. 4A-4E The diagram shown in the figure can be a cross-sectional view of an optical device.

[0169] FIG. 4A An example of an optical device 401 supporting a mode multiplexer or demultiplexer according to the examples disclosed herein is shown. The mode multiplexer or demultiplexer uses metamaterials for fiber optic communication. The optical device 401 can utilize a light-transmitting metamaterial structure, a light-transmitting substrate, and a reflector in a folded design to perform mode multitasking or mode demultiplexing techniques. The optical device 401 can be a reference... FIG. 2B An example of the optical device 202 described.

[0170] Optical device 401 may include multiple stages 410 adjacent to or in contact with a metamaterial, a first reflector 415, and a second reflector 420. Each stage 410 of the metamaterial may include multiple metamaterial structures. The substrate 405, the multiple stages 410, the first reflector 415, and the second reflector 420 may exhibit a folded design, wherein light bounces between the two reflectors 415 and 420 and interacts with the metamaterial stage 410 based on the light following the reflection path. Optical device 401 may include any number of metamaterial stages 410 to perform mode multitasking or mode demultitasking techniques. For example, the optical device may include a first stage 410-a, a second stage 410-b, a third stage 410-c, or any number of stages 410-N.

[0171] Substrate 405 may be a light-transmitting substrate configured to support metamaterial grade 410. Substrate 405 may have one or more parameters defining the structure, such as height or cross-sectional area. Substrate 405 may be a reference. FIG. 2A-2B An example of the substrate 205 described.

[0172] Metamaterial stage 410 may include one or more transmissive metamaterial structures, the metamaterial structures being configured to shift the phase profile of an optical signal (e.g., light) passing through the metamaterial structure. Each stage 410 of the metamaterial may be positioned in proximity to or in contact with at least one substrate 405. The metamaterial structure of stage 410 may be a reference. FIG. 2A-2BExamples of described metamaterial structures 210 are given. In other examples, the metamaterial structure of metamaterial level 410 may have one or more parameters defining the metamaterial structure, such as cross-sectional profile, cross-sectional area, or height. In some examples, each level 410 of the metamaterial may be designed to have a different phase profile, and the combined phase profile of each level 410 may produce the overall phase profile of the optical device 401. In some examples, based on the desired phase profile of the optical device 401, one or more levels 410 of the metamaterial may have parameters different from those of the other levels 410 of the metamaterial in the optical device 401. In some examples, each level 410 of the metamaterial in the optical device 401 may have the same parameters.

[0173] The first reflector 415 may be connected to the substrate 405. The first reflector 415 may be configured to reflect optical signals in the optical device 401 along an optical path and to subsequent stages 410 of the metamaterial, the second reflector 420, or any combination thereof. In some cases, the first reflector 415 may be formed of a reflective material having relatively high reflectivity, such as gold.

[0174] The second reflector 420 may be located near or adjacent to the metamaterial stage 410. The second reflector 420 may be configured to reflect optical signals in the optical device 401 along an optical path and to subsequent stages 410 of the metamaterial, the first reflector 415, or any combination thereof. In some cases, the second reflector 420 may be formed of a reflective material having relatively high reflectivity, such as gold.

[0175] In some examples, the optical device 401 may include a cladding 425, which may be configured to protect the metamaterial structure of the stage 410 from damage, mitigate the loss of optical signals interacting with the metamaterial structure, or any combination thereof. In some cases, the cladding 425 may be positioned between the surface of the metamaterial structure and the second reflector 420 adjacent to the metamaterial stage 410. In such cases, a distance may be formed between the surface of the metamaterial structure and the surface of the second reflector 420 (e.g., see reference 425). FIG. 2B (Described distance 230). The surface of the metamaterial structure near the second reflector 420 can be relative to a different surface of the metamaterial structure in contact with the substrate 405.

[0176] The first reflector 415, the second reflector 420, and the metamaterial stage 410 can be configured to guide an optical signal along a desired optical path in the optical device 401. In some cases, one or more positions of the first reflector 415 and the second reflector 420 can be configured to redirect the light in different directions. For example, the optical signal may strike the reflector at an angle approximately orthogonal to the plane of the reflector, and the reflector may be configured to guide the optical signal in different directions. In some examples, the metamaterial stage 410 can be configured to change the direction of the optical signal. In some cases, the first reflector 415, the second reflector 420, or at least one metamaterial stage 410, or any combination thereof, can be configured to change the propagation direction of the optical signal.

[0177] Optical device 401 may include an input aperture 430 for receiving an input optical signal into optical device 401, or an output aperture 435 for outputting an output optical signal from optical device 401, or both. In an illustrative example, optical device 401, input aperture 430, and output aperture 435 are formed by a first reflector 415. One or more sidewalls 440 of the first reflector 415 may form the input aperture 430. Similarly, one or more sidewalls 445 of the first reflector 415 may form the output aperture 435. In some examples, the first reflector 415 may form one aperture (e.g., input aperture 430 or output aperture 435), and a second reflector 420 may form another aperture (e.g., input aperture 430 or output aperture 435).

[0178] Optical device 401 can be configured as a mode multiplexer. In some cases, optical device 401 can be configured as a mode demultiplexer. In this case, the input and output of optical device 401 can be reversed. Input fiber 450 can be positioned at a first distance from input aperture 430 and can be configured to transmit one or more optical signals to optical device 401. Input fiber 450 can be a reference... FIG. 1A Examples of optical communication links 105 or one or more optical communication links 130 are described. Output fiber 455 can be positioned at a second distance from the output aperture 435 of optical device 401 and can be configured to receive one or more optical signals output from optical device 401. Output fiber 455 can be a reference... FIG. 1AAn example of the described optical communication link 105. In some cases, the input fiber 450, the output fiber 455, or any combination thereof may be an example of a fiber optic array having multiple fibers. In some cases, the first distance may be the same as the second distance. In some cases, the size of the first distance may be different from the size of the second distance. In some cases, additional spacers, additional OCAs, or combinations thereof may be placed between the input fiber 450 and the optical device 401. In some cases, additional spacers, additional OCAs, or combinations thereof may be placed between the output fiber 455 and the optical device 401. Such additional spacers or additional OCAs may be configured to reduce back reflection, protect metamaterials, or provide spacing between the fiber and the optical device, or any combination thereof.

[0179] In an example where optical device 401 is configured as a mode multiplexer, input fiber 450 may be an example of an fiber array, and two or more optical signals with different modes or different versions of the same mode may be transmitted into optical device 401. The two or more optical signals may be reflected through optical device 401 by first reflector 415 and second reflector 420, and may pass through different stages 410 of the metamaterial (and other components) of optical device 401. At each stage 410, the phase profiles of the two or more optical signals may be shifted or altered. Through different stages 410, optical device 401 can convert two or more optical signals into different optical signals propagating along different modes of FMF or MMF. Output fiber 455 may be an example of a single output fiber, and may be configured to receive optical signals propagating along different guiding modes. In some cases, input fiber 450 may include one or more SMFs, and one or more input signals may be single-mode input signals. In other examples, input fiber 450 may include one or more FMFs or MMFs, and at least one input signal may be a multimode signal. Alternatively or additionally, the output fiber 455 may include one or more SMFs, and the one or more output signals may be single-mode output signals. In other examples, the output fiber 455 may include one or more FMFs or MMFs, and at least one input signal may be a multimode signal.

[0180] In an example where optical device 401 is configured as a mode demultiplexer, input fiber 450 may be a single fiber, and optical signals propagating in different modes can be transmitted along this single fiber into optical device 401. Optical signals can be reflected through optical device 401 by first reflector 415 and second reflector 420, and can pass through different stages 410 of the metamaterial (and other components) of optical device 401. At each stage 410, the phase profile of the optical signal can be shifted or altered. Through different stages 410, optical device 401 can convert the optical signal into two or more different optical signals with different modes (e.g., multiple optical signals propagating along the SMF). Output fiber 455 may be an example of a fiber array, and can be configured to receive two or more optical signals that have been demultiplexed from the original optical signal.

[0181] In certain situations, optical device 401 can be used for SDM / MDM applications. Optical device 401 can coherently shape the modes of light, from one mode to another. Light in the first stage of the metamaterial can propagate in many directions and may interfere when it propagates to or over the second stage of the metamaterial. Light in the second stage of the metamaterial can propagate in multiple directions and may interfere when it propagates to or over the third stage of the metamaterial.

[0182] FIG. 4B An example of an optical device 402 supporting a mode multiplexer or demultiplexer according to the examples disclosed herein is shown. The mode multiplexer or demultiplexer uses metamaterials for fiber optic communication. The optical device 402 can utilize a light-transmitting metamaterial structure, a light-transmitting substrate, and a reflector in a folded design to perform mode multitasking or mode demultiplexing techniques. The optical device 402 can be a reference... FIG. 2B and FIG. 4A Examples of optical devices 202 and 401 are described. Optical device 402 can be similarly represented as optical device 401, and components that are similarly numbered and named can be similarly represented.

[0183] Optical device 402 may include reference FIG. 4AThe described optical device 401 has several different features. For example, an input aperture 430 can be formed in the second reflector 420 via one or more sidewalls 440, and an output aperture 435 can be formed in the first reflector 415 via one or more sidewalls 445. The input optical signal can pass through the first stage 410-a of the metamaterial before passing through the substrate 405. In this case, the input aperture 430 can be located in the second reflector 420, which is located near the metamaterial stage 410. Additionally, the input signal can be transmitted at approximately orthogonal angles relative to the plane of the input aperture 430 or the plane of the first stage 410-a of the metamaterial. The first stage 410-a of the metamaterial can be configured to change the propagation direction of the optical signal. The last stage 410-N of the metamaterial can also be configured to change the propagation direction of the optical signal. In some cases, the second reflector 420, the last stage 410-N of the metamaterial, or any combination thereof, can be configured to change the propagation direction of the optical signal. In some cases, the first stage 410-a of the metamaterial can be an example of the transmission stage of the metamaterial, while the subsequent stage 410 of the metamaterial can be an example of the reflection stage of the metamaterial.

[0184] FIG. 4C An example of an optical device 403 supporting a mode multiplexer or demultiplexer according to the examples disclosed herein is shown. The mode multiplexer or demultiplexer uses metamaterials for fiber optic communication. The optical device 403 can utilize a light-transmitting metamaterial structure, a light-transmitting substrate, and a reflector in a folded design to perform mode multitasking or mode demultiplexing techniques. The optical device 403 can be a reference... FIG. 2B and FIG. 4A-4B Examples of optical devices 202, 401 and 402 are described. Optical device 403 can be similarly represented as optical device 401, and components that are similarly numbered and named can be similarly represented.

[0185] Optical device 403 may include reference FIG. 4AThe described optical device 401 has several distinct features. An input aperture 430 can be formed in the second reflector 420 via one or more sidewalls 440, and an output aperture 435 can continue to be formed in the first reflector 415 via one or more sidewalls 445. The input optical signal can pass through the cladding 425 (without any metamaterial level) before passing through the substrate 405. In this case, the input aperture 430 can be located in the second reflector 420, which is located near the metamaterial level 410. The input signal can be configured to enter the optical device 403 at an angle that is not orthogonal to the plane defined by the input aperture 430, the plane defined by the reflectors 415 and 420, the plane defined by the cladding 425, the plane defined by the metamaterial level 410, or the plane defined by the substrate 405, or any combination thereof. The non-orthogonal angle can be configured to cause the optical signal to be reflected between the reflectors 415 and 420 along an optical path to the continuous metamaterial level 410. Non-orthogonal angles can be configured to cause the optical signal to be reflected between reflectors 415 and 420 along an optical path to the metamaterial's successive stages 410. The final stage 410-N of the metamaterial can also be configured to change the propagation direction of the optical signal. In some cases, the second reflector 420, the final stage 410-N of the metamaterial, or any combination thereof, can be configured to change the propagation direction of the optical signal.

[0186] FIG. 4D An example of an optical device 406 supporting a mode multiplexer or demultiplexer according to the examples disclosed herein is shown. The mode multiplexer or demultiplexer uses metamaterials for fiber optic communication. Optical device 406 can utilize a light-transmitting metamaterial structure, a light-transmitting substrate, and a reflector in a folded design to perform mode multitasking or mode demultiplexing techniques. Optical device 406 can be a reference... FIG. 2B and FIG. 4A-4C Examples of optical devices 202, 401, 402 and 403 are described. Optical device 406 can be similarly represented as optical device 401, and similarly numbered and named components can be similarly represented.

[0187] Optical device 406 may include reference FIG. 4AThe optical device 401 is described with some different features. For example, the metamaterial stage 410 may be positioned near the first reflector 415, rather than near the second reflector 420 (compared to the optical device 401). An input aperture 430 may be formed in the second reflector 420 by one or more sidewalls 440, and an output aperture 435 may continue to be formed in the first reflector 415 by one or more sidewalls 445. The input aperture 430 is located in the second reflector 420, which is located on the opposite side of the substrate 405 opposite to the metamaterial stage 410. An input signal may be transmitted into the optical device 403 at an angle that is not orthogonal to the plane defined by the input aperture 430, the plane defined by the reflectors 415 and 420, the plane defined by the cladding 425, the plane defined by the metamaterial stage 410, or the plane defined by the substrate 405, or any combination thereof. The non-orthogonal angle can be configured to cause the optical signal to be reflected between reflectors 415 and 420 along the optical path to the metamaterial successive stage 410. The output signal can be transmitted out of the output aperture 435 at an angle that is not orthogonal to the plane defined by the input aperture 430, the plane defined by reflectors 415 and 420, the plane defined by the cladding 425, the plane defined by the metamaterial stage 410, or the plane defined by the substrate 405, or any combination thereof.

[0188] FIG. 4E An example of an optical device 407 supporting a mode multiplexer or demultiplexer according to the examples disclosed herein is shown. The mode multiplexer or demultiplexer uses metamaterials for fiber optic communication. The optical device 407 can utilize a light-transmitting metamaterial structure, a light-transmitting substrate, and a reflector in a folded design to perform mode multitasking or mode demultiplexing techniques. The optical device 407 can be a reference... FIG. 2B and FIG. 4A-4D Examples of optical devices 202, 401, 402, 403 and 406 are described. Optical device 407 can be similarly represented as optical device 401, and similarly numbered and named components can be similarly represented.

[0189] Optical device 407 may include reference FIG. 4AThe optical device 401 is described with some different features. The optical device 407 may include a metamaterial stage 410 located near a first reflector 415 and a second reflector 420. For example, a first metamaterial stage 410-a may be positioned adjacent to the first reflector 415, and a second metamaterial stage 410-b may be positioned adjacent to the second reflector 420. The optical device 407 also includes a second cladding layer 425-a to protect the metamaterial stage 410 located near the first reflector 415. In the optical device 407, the metamaterial stage 410 may be located at each reflection point in the optical path within the optical device 407. In some examples, at least one reflection point in the optical device 407 may not be associated with a metamaterial stage. In such examples, an optical signal may be reflected at least once by one of the reflectors 415 or 420 without passing through the metamaterial stage 410.

[0190] An input aperture 430 can be formed in the second reflector 420 via one or more sidewalls 440, and an output aperture 435 can be formed in the first reflector 415 via one or more sidewalls 445. The input optical signal can pass through the cladding 425 (without any metamaterial stage) before passing through the substrate 405. In this case, the input aperture 430 can be located in the second reflector 420, which is located near the metamaterial stage 410. In some examples, the metamaterial stage 410 can be positioned directly below the input aperture 430 in the cladding 425. Additionally or alternatively, in some examples, the metamaterial stage can be positioned in the cladding 425-a, just above the output aperture 435. The first stage 410-a and the last stage 410-N of the metamaterial can also be configured to change the propagation direction of the optical signal. In some cases, the first reflector 415, the first stage 410-a of the metamaterial, or any combination thereof can be configured to change the propagation direction of the optical signal. In some cases, the second reflector 420, the final stage 410-N of the metamaterial, or any combination thereof, can be configured to change the direction of propagation of the optical signal.

[0191] In some examples, optical devices 401, 402, 403, 406, or 407 can be configured as examples of resonant folding designs. In such designs, the overall structure of the optical devices is similar to that used in folding designs. The difference between folding and resonant folding designs can include the design of the phase profiles of the metamaterial levels. For example, in stacked and folded designs, the number of times light interacts with the individual levels of the metamaterial may be fixed. However, in a resonant folding design, light may interact with the individual levels of the metamaterial a relatively large number of times (e.g., hundreds or thousands), or essentially an indefinite or infinite number of interactions. In a resonant folding design, the top and bottom surfaces of substrate 405 can form a Fabry-Perot cavity, with one or more metamaterial levels 410 having specific phase profiles located near these surfaces. In such examples, the individual levels 410 of the metamaterial interact more strongly with light than in designs where a single level of the metamaterial interacts with light only once.

[0192] To find a suitable phase profile for the resonant structure, iterative solvers (such as conjugate gradient (CG), conjugate gradient squared (CGS), generalized minimum residual iteration (GMRES), relaxed GMRES (LGMRES), etc.) can be used to solve for the electric field within the metamaterial under fixed conditions. Adjoint analyses similar to those described above can be performed to calculate the derivative of the quality factor with respect to the phase profile, and nonlinear enhancements can be used to converge the design.

[0193] FIG. 5A-5F An example of a method for manufacturing an optical device according to the examples disclosed herein is shown, the optical device supporting mode multiplexers or demultiplexers for optical fiber communication using metamaterials. FIG. 5A-5F An example of a method for manufacturing an optical device according to the examples disclosed herein is shown, the optical device supporting mode multiplexers or demultiplexers for optical fiber communication using metamaterials. FIG. 5A-5F Each figure shows a perspective view of a cut-off portion of a larger optical device. The cut-off portions in each figure have been limited to show how various aspects of the optical device are formed, but additional structures and functions supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials are considered. The operations described herein can be used to form references. FIG. 2A-4E Any optical device described. The method may be a top-down approach to forming the optical device.

[0194] FIG. 5A An example of a first operation of a method for manufacturing an optical device according to the examples disclosed herein, the optical device supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials, is shown. This first operation may not be the first step in the manufacturing process of the optical device, but rather... FIG. 5A-5FThe first operation described in the text. FIG. 5A An optical device 501 is shown, which includes a substrate 510 and a metamaterial layer 515. The optical device 501 is a device that appears after the completion of the first operation in the manufacturing process.

[0195] The first operation may include forming a substrate 510 (e.g., through one or more deposition steps and / or one or more etching steps). The substrate 510 may be a reference. FIG. 2A-4E Examples of substrates 205, 305, and 405 are described. In some cases, substrate 510 may be formed of glass or fused quartz. In some examples, substrate 510 may be grown instead of deposited. The terms deposition and growth may be used interchangeably herein.

[0196] Additionally, as part of the first operation, a metamaterial layer 515 may be deposited on the substrate 510. In some cases, the metamaterial layer 515 may be an example of a metamaterial used to form a metamaterial structure in a completed optical device. The metamaterial layer 515 may be a reference. FIG. 2A-4E Describe metamaterial structures or examples at the metamaterial level.

[0197] FIG. 5B An example of a second operation of a method for manufacturing an optical device according to the examples disclosed herein, the optical device supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials, is shown. The second operation is described in reference... FIG. 5A The described first operation occurs after the first operation. In some cases, other steps or operations may occur between the first and second operations. FIG. 5B An optical device 502 is shown, which includes a substrate 510, a metamaterial layer 515, and a photoresist layer 520. The optical device 502 is a device that appears after the completion of a second operation in the manufacturing process.

[0198] In the second operation, a resist layer 520 is deposited or coated onto the layer of metamaterial 515. In some cases, the resist layer 520 may be an example of a hard mask material or a sacrificial layer or any combination thereof.

[0199] FIG. 5C An example of a third operation of a method for manufacturing an optical device according to the examples disclosed herein, the optical device supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials, is shown. The third operation is described in reference... FIG. 5B The second operation described occurs after the third operation. In some cases, other steps or operations may occur between the second and third operations. FIG. 5CAn optical device 503 is shown, comprising a substrate 510, a metamaterial layer 515, and a plurality of hard masks 525 formed of a resist layer 520. The optical device 503 is a device that appears after the completion of the third operation in the manufacturing process.

[0200] In the third operation, a portion of the resist layer 520 is removed to form a plurality of hard masks 525. Each of the plurality of hard masks 525 includes one or more parameters (e.g., cross-sectional profile, cross-sectional area, or height) configured to control the parameters of the metamaterial structure produced by the plurality of hard masks 525. The plurality of hard masks 525 can be formed using one or more etching processes, electron beam lithography, photolithography, nanoimprint lithography, or any combination thereof.

[0201] FIG. 5D An example of a fourth operation of a method for manufacturing an optical device according to the examples disclosed herein, the optical device supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials, is shown. The fourth operation is described in reference... FIG. 5C The third operation described occurs after this one. In some cases, other steps or operations may occur between the third and fourth operations. FIG. 5D An optical device 504 is shown, comprising a substrate 510 and a plurality of metamaterial structures 530 formed by layers of metamaterial 515, and formed based on parameters of a plurality of hard masks 525. The optical device 504 is a device that appears after the completion of the fourth operation in the manufacturing process.

[0202] In the fourth operation, portions of the metamaterial layer 515 and the plurality of hard masks 525 are removed to form a plurality of metamaterial structures 530. In some cases, a pattern of the resist layer may be etched. Each of the plurality of metamaterial structures 530 includes one or more parameters (e.g., cross-sectional profile, cross-sectional area, or height) configured based on the parameters of the hard mask initially positioned above the metamaterial structure. The plurality of metamaterial structures 530 may be formed using one or more etching processes, electron beam lithography, photolithography, nanoimprint lithography, or any combination thereof. In some cases, one of the processes listed above may be used as part of the fourth operation. In some cases, two or more of the processes listed above may be used as part of the fourth operation. In some cases, two or more of the processes listed above may be used as part of the fourth operation.

[0203] FIG. 5E An example of a fifth operation of a method for manufacturing an optical device according to the examples disclosed herein, the optical device supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials, is shown. The fifth operation is described in reference... FIG. 5DThe fourth operation described occurs after this one. In some cases, other steps or operations may occur between the fourth and fifth operations. FIG. 5E An optical device 505 is shown, which includes a substrate 510, multiple metamaterial structures 530, and a cladding 535. The optical device 505 is a device that appears after the completion of the fifth operation in the manufacturing process.

[0204] In the fifth operation, a cladding layer 535 is deposited on the substrate 510 and multiple metamaterial structures 530. The cladding layer 535 can be a reference. FIG. 2A and 4A Examples of cladding 215 or cladding 425 described in -4E. Cladding 535 can be configured to protect metamaterial structure 530 from damage, mitigate loss of optical signals interacting with the metamaterial structure, or any combination thereof.

[0205] FIG. 5F An example of a sixth operation of a method for manufacturing an optical device according to the examples disclosed herein, the optical device supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials, is shown. The sixth operation is described in reference... FIG. 5D The fifth operation described occurs after the sixth operation. In some cases, other steps or operations may occur between the fifth and sixth operations. FIG. 5F An optical device 506 is shown, which includes a substrate 510, multiple metamaterial structures 530, a cladding 535, and a reflector 540. The optical device 506 is a device that appears after the completion of the sixth operation in the manufacturing process.

[0206] In the sixth operation, material is deposited to form reflector 540. In some cases, this material is a reflective material (e.g., a metal such as gold). In other cases, this material is coated with a reflective material (e.g., a metal such as gold) to form reflector 540. Reflector 540 may be formed to be positioned adjacent to or in contact with cladding 535. In some cases, cladding 535 is located between metamaterial structure 530 and reflector 540. Reflector 540 may be a reference. FIG. 2B and FIG. 4A-4E Examples of reflectors 220, 415, and 420 are described. In some cases, optical device 506 may represent a reference. FIG. 2A-4E A portion of the complete memory device described.

[0207] In a top-down method for manufacturing optical devices, the material for the metamaterial structure is placed on a substrate 510, such as... FIG. 5AAs described, processes such as chip bonding and / or thin film deposition, such as plasma-enhanced chemical vapor deposition (PECVD), low-pressure chemical vapor deposition (LPCVD), atomic layer deposition (ALD), thermal evaporation, electron beam evaporation, sputtering, etc., are used for patterning structures. FIG. 5B and 5C The patterning method can be photolithography, such as electron beam lithography, photolithography, nanoimprint lithography, or any combination thereof. Other techniques, such as self-assembly, can also be used for patterning devices. Depending on the technology and materials chosen for the device, different resists and etching techniques can be used to transfer the pattern to the metamaterial layer, such as... FIG. 5D As shown (for example, this technique could be a dry etching technique, such as reactive ion etching, inductively coupled plasma etching, or ion milling, or any combination thereof). In some cases, another layer of material can be added on top of the thin film layer (e.g., metamaterial 515) to act as a hard mask during the etching process, instead of using a resist as an etching shield. Depending on the design, a cladding layer can be added to protect or support this structure, using coating techniques (e.g., spin coating) or deposition techniques (e.g., as described herein) FIG. 5E (as shown) to add a cladding layer. The deposition techniques described herein (e.g., FIG. 5F As shown, a reflector (e.g., metal) layer is added on top of the cladding.

[0208] FIG. 6A-6F An example of a method for manufacturing an optical device according to the examples disclosed herein is shown, the optical device supporting mode multiplexers or demultiplexers for optical fiber communication using metamaterials. FIG. 6A-6F Each figure shows a perspective view of a cut-off portion of a larger optical device. The cut-off portions in each figure have been limited to show how various aspects of the optical device are formed, but additional structures and functions supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials are considered. The operations described herein can be used to form references. FIG. 2A-4E Any optical device described. The method can be a bottom-up approach to forming the optical device.

[0209] FIG. 6A An example of a first operation of a method for manufacturing an optical device according to the examples disclosed herein, the optical device supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials, is shown. This first operation may not be the first step in the manufacturing process of the optical device, but rather... FIG. 6A-6F The first operation described in the text. FIG. 6A An optical device 601 is shown, which includes a substrate 610 and a resist layer 615. The optical device 601 is a device that appears after the completion of the first operation in the manufacturing process.

[0210] The first operation may include forming substrate 610 (e.g., through one or more deposition steps and / or one or more etching steps). Substrate 610 may be a reference. FIG. 2A-4E Examples of substrates 205, 305, and 405 are described. In some examples, substrate 610 may be grown instead of deposited (e.g., using a Czeklaussky process). The terms deposition and growth may be used interchangeably herein.

[0211] Additionally, as part of the first operation, a resist layer 615 may be deposited or coated on the substrate 610. In some cases, the resist layer 615 may be an example of a hard mask material or a sacrificial layer or any combination thereof.

[0212] FIG. 6B An example of a second operation of a method for manufacturing an optical device according to the examples disclosed herein, the optical device supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials, is shown. The second operation is described in reference... FIG. 6A The described first operation occurs after the first operation. In some cases, other steps or operations may occur between the first and second operations. FIG. 6B An optical device 602 is shown, which includes a substrate 610, a resist layer 615, and a plurality of cavities 620 formed in the resist layer 615. The optical device 602 is a device that appears after a second operation in the manufacturing process is completed.

[0213] In the second operation, a portion of the resist layer 615 is removed to form a plurality of cavities 620. In some cases, the pattern of the resist layer 615 may be etched. Each of the plurality of cavities 620 may include one or more parameters (e.g., cross-sectional profile, cross-sectional area, or height) configured to control the metamaterial structure produced by the plurality of cavities 620. The plurality of cavities 620 may be formed using one or more etching processes, electron beam lithography, photolithography, nanoimprint lithography, or any combination thereof.

[0214] FIG. 6C An example of a third operation of a method for manufacturing an optical device according to the examples disclosed herein, the optical device supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials, is shown. The third operation is described in reference... FIG. 6B The second operation described occurs after the third operation. In some cases, other steps or operations may occur between the second and third operations. FIG. 6C An optical device 603 is shown, which includes a substrate 610, a resist layer 615, and a metamaterial layer 625. The optical device 603 is a device that appears after the completion of the third operation in the manufacturing process.

[0215] In the third operation, a metamaterial layer 625 can be deposited on the resist layer 615 and in the plurality of cavities 620 formed in the resist layer 615. In some cases, the metamaterial layer 625 may be an example of a metamaterial used to form a metamaterial structure in a completed optical device. The metamaterial layer 625 may be a reference. FIG. 2A-4E Examples of metamaterial structures or metamaterial-level structures are described. In some cases, the metamaterial layer 625 may also include multiple cavities after deposition. In this case, the thickness of the deposited film may be uniform throughout the device. In such cases, the material filling the multiple cavities 620 of the metamaterial layer 625 may leave similar cavities above it within the metamaterial layer 625.

[0216] FIG. 6D An example of a fourth operation of a method for manufacturing an optical device according to the examples disclosed herein, the optical device supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials, is shown. The fourth operation is described in reference... FIG. 6C The third operation described occurs after this one. In some cases, other steps or operations may occur between the third and fourth operations. FIG. 6D An optical device 604 is shown, comprising a substrate 610 and a plurality of metamaterial structures 630 formed by a metamaterial layer 625, and formed based on parameters of the plurality of cavities 620. The optical device 604 is a device that appears after the completion of the fourth operation in the manufacturing process.

[0217] In the fourth operation, a portion of the metamaterial layer 625 and the remainder of the resist layer 615 are removed to form (or expose) a plurality of metamaterial structures 630. Each of the plurality of metamaterial structures 630 includes one or more parameters (e.g., cross-sectional profile, cross-sectional area, or height) configured based on the parameters of the cavity into which the metamaterial layer 625 is deposited. In some cases, one or more chemicals may be applied to the optical device 604 to remove the remaining resist layer and the metamaterial on top of the remaining resist layer. In some cases, this process may be referred to as lift-off. The plurality of metamaterial structures 630 may be formed using one or more etching processes, electron beam lithography, photolithography, nanoimprinting, or lift-off processes, or any combination thereof. In some cases, one of the processes listed above may be used as part of the fourth operation. In some cases, two or more of the processes listed above may be used as part of the fourth operation. In some cases, two or more of the processes listed above may be used as part of the fourth operation.

[0218] FIG. 6EAn example of a fifth operation of a method for manufacturing an optical device according to the examples disclosed herein, the optical device supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials, is shown. The fifth operation is described in reference... FIG. 6D The fourth operation described occurs after this one. In some cases, other steps or operations may occur between the fourth and fifth operations. FIG. 6E An optical device 605 is shown, which includes a substrate 610, multiple metamaterial structures 630, and a cladding 635. The optical device 605 is a device that appears after the completion of the fifth operation in the manufacturing process.

[0219] In the fifth operation, a cladding layer 635 is deposited on the substrate 610 and multiple metamaterial structures 630. The cladding layer 635 can be a reference. FIG. 2A and 4A Examples of cladding 215 or cladding 425 described in -4E. Cladding 635 can be configured to protect metamaterial structure 630 from damage, mitigate loss of optical signals interacting with the metamaterial structure, or any combination thereof.

[0220] FIG. 6F An example of a sixth operation of a method for manufacturing an optical device according to the examples disclosed herein, the optical device supporting mode multiplexers or demultiplexers for fiber optic communication using metamaterials, is shown. The sixth operation is described in reference... FIG. 6E The fifth operation described occurs after the sixth operation. In some cases, other steps or operations may occur between the fifth and sixth operations. FIG. 6F An optical device 606 is shown, which includes a substrate 610, multiple metamaterial structures 630, a cladding 635, and a reflector 640. The optical device 606 is a device that appears after the completion of the sixth operation in the manufacturing process.

[0221] In the sixth operation, material is deposited to form reflector 640. In some cases, this material is a reflective material (e.g., a metal such as gold). In other cases, this material is coated with a reflective material (e.g., a metal such as gold) to form reflector 640. Reflector 640 may be formed to be positioned adjacent to or in contact with cladding 635. In some cases, cladding 635 is located between metamaterial structure 630 and reflector 640. Reflector 640 may be a reference. FIG. 2B and FIG. 4A-4E Examples of reflectors 220, 415, and 420 are described. In some cases, optical device 606 may represent a reference. FIG. 2A-4E A portion of the complete memory device described.

[0222] In a bottom-up approach, the same methods as a top-down approach can be used (e.g., see...). FIG. 6A and6B A similar photolithography technique is used to first create a reverse pattern of the desired structure. A thin film layer can then be grown on top of the patterned resist layer 615 to fill the holes (e.g., see...). FIG. 6C After the extraction process (e.g., see...) FIG. 6D This allows the removal of the resist layer 615 and the thin film on top of the resist, transferring the pattern onto the film layer to create a metamaterial structure. Depending on the design, cladding can be added to protect or support the structure, using coating techniques (e.g., spin coating) or deposition techniques (e.g., as described herein). FIG. 6E (as shown) to add a cladding layer. The deposition techniques described herein (e.g., FIG. 6F As shown, a reflector (e.g., metal) layer is added on top of the cladding.

[0223] FIG. 7 A flowchart is shown illustrating method 700 for supporting the use of metamaterials in optical fiber communications as described herein, according to examples disclosed herein. Operation of method 700 may be implemented by a manufacturing system or one or more controllers associated with the manufacturing system. In some examples, one or more controllers may execute a set of instructions to control one or more functional components of the manufacturing system to perform the described functions. Additionally or alternatively, one or more controllers may use dedicated hardware to perform aspects of the described functions.

[0224] In step 705, method 700 may include growing a light-transmitting substrate. The operation of step 705 may be performed according to the method described herein.

[0225] In 710, method 700 may include depositing a metamaterial layer on a substrate. The operation of 710 may be performed according to the method described herein.

[0226] In 715, method 700 may include depositing a resist layer on the metamaterial layer. The operation of 715 can be performed according to the method described herein.

[0227] At 720, method 700 may include etching a pattern of a resist layer to form a set of hard masks. In some cases, a portion of the resist layer may be etched. The operation of 720 may be performed according to the methods described herein.

[0228] At 725, method 700 may include etching exposed portions of this set of hard masks and metamaterial layers based on an etch resist layer to form a set of metamaterial structures, wherein multiple metamaterial structures are configured to shift a first phase profile of a first optical signal having a first mode with a second phase profile of a second optical signal having a second mode to generate a third optical signal having a third mode and a fourth optical signal having a fourth mode. In some cases, a set of metamaterial structures can be formed by etching the metamaterial layers simultaneously, using the resist as one or more hard masks during the etching process. The operation at 725 may be performed according to the method described herein.

[0229] In some examples, the apparatus described herein can perform one or more methods, such as method 700. The apparatus may include features, means, or instructions (e.g., a non-transitory computer-readable medium storing instructions executable by a processor) for growing an optically transmissive substrate, depositing a metamaterial layer on the substrate, depositing a photoresist layer on the metamaterial layer, etching a portion of the photoresist layer to form a set of hard masks, and etching the set of hard masks and exposed portions of the metamaterial layer based on the etching of the portion of the photoresist layer to form a set of metamaterial structures. The set of metamaterial structures may be configured to shift a first phase profile of a first optical signal having a first mode with a second phase profile of a second optical signal having a second mode to generate a third optical signal having a third mode and a fourth optical signal having a fourth mode.

[0230] Some examples of the method 700 and apparatus described herein may further include operations, features, components, or instructions for depositing a reflective material based on etching exposed portions of the set of hard masks and metamaterial layers to form a reflector at one end of the set of metamaterial structures. Some examples of the method 700 and apparatus described herein may further include operations, features, components, or instructions for depositing a cladding layer on the set of metamaterial structures and on exposed portions of the substrate based on etching exposed portions of the set of hard masks and metamaterial layers, wherein the deposition of the reflective material may be based on the deposition of the cladding layer. In some examples of the method 700 and apparatus described herein, the reflective material may be deposited on a cladding layer that may be located between the set of metamaterial structures and the reflective material.

[0231] In some examples of the method 700 and apparatus described herein, each metamaterial structure in this set of metamaterial structures may have one or more parameters, including the height of the metamaterial structure, the cross-sectional profile of the metamaterial structure, the diameter of the metamaterial structure, the dielectric properties of the metamaterial structure, or any combination thereof. In some examples of the method 700 and apparatus described herein, at least some of the one or more parameters of each metamaterial structure may be based on a second cross-sectional profile of an associated hard mask.

[0232] FIG. 8A flowchart is shown illustrating method 800 for supporting the use of metamaterials in optical fiber communications as described herein, according to examples disclosed herein. Operation of method 800 may be implemented by a manufacturing system or one or more controllers associated with the manufacturing system. In some examples, one or more controllers may execute a set of instructions to control one or more functional components of the manufacturing system to perform the described functions. Additionally or alternatively, one or more controllers may use dedicated hardware to perform aspects of the described functions.

[0233] At 805, method 800 may include depositing a light-transmitting substrate. The operation at 805 may be performed according to the method described herein.

[0234] In 810, method 800 may include depositing a resist layer on a substrate. Operation 810 may be performed according to the methods described herein.

[0235] At 815, method 800 may include etching a pattern of the resist layer to form a set of cavities in the resist layer. In some cases, a portion of the resist layer may be etched. The operation at 815 may be performed according to the method described herein.

[0236] In 820, method 800 may include depositing a metamaterial layer on a resist layer forming a cavity assembly, the metamaterial layer filling at least some of the cavities in the cavity assembly formed in the resist layer. Operation of 820 may be performed according to the methods described herein.

[0237] At 825, method 800 may include removing the metamaterial layer and the resist layer based on depositing a metamaterial layer on the resist layer to form a set of metamaterial structures, wherein multiple metamaterial structures are configured to shift a first phase profile of a first optical signal having a first mode and a second phase profile of a second optical signal having a second mode to generate a third optical signal having a third mode and a fourth optical signal having a fourth mode. In some cases, one or more chemicals may be applied to the structure to remove the remaining resist layer and the metamaterial on top of the remaining resist layer. In some cases, this process may be referred to as lift-off. The operation at 825 may be performed according to the method described herein.

[0238] In some examples, the apparatus described herein can perform one or more methods, such as method 800. The apparatus may include features, components, or instructions (e.g., a non-transitory computer-readable medium storing instructions executable by a processor) for depositing a light-transmitting substrate, depositing a resist layer on the substrate, etching a portion of the resist layer to form a set of cavities in the resist layer, depositing a metamaterial layer on the resist layer forming the set of cavities (the metamaterial layer filling at least a portion of the cavities formed in the resist layer), and etching the metamaterial layer and the resist layer to form a set of metamaterial structures based on the deposition of the metamaterial layer on the resist layer. The set of metamaterial structures may be configured to shift a first phase profile of a first optical signal having a first mode and a second phase profile of a second optical signal having a second mode to generate a third optical signal having a third mode and a fourth optical signal having a fourth mode.

[0239] Some examples of the methods 800 and apparatus described herein may further include operations, features, components, or instructions for depositing a reflective material based on etching a metamaterial layer and a resist layer to form a reflector at one end of the set of metamaterial structures. Some examples of the methods 800 and apparatus described herein may further include operations, features, components, or instructions for depositing a cladding layer on the set of metamaterial structures and on exposed portions of a substrate based on etching a metamaterial layer and a resist layer, wherein the deposition of the reflective material may be based on the deposition of the cladding layer. In some examples of the methods 800 and apparatus described herein, the reflective material may be deposited on a cladding layer that may be located between the set of metamaterial structures and the reflective material.

[0240] In some examples of the method 800 and apparatus described herein, each metamaterial structure in this set of metamaterial structures may have one or more parameters of the metamaterial structure, including the height of the metamaterial structure, the cross-sectional profile of the metamaterial structure, the diameter of the metamaterial structure, the dielectric properties of the metamaterial structure, or any combination thereof. In some examples of the method 800 and apparatus described herein, at least some of the one or more parameters of each metamaterial structure may be based on a second cross-sectional profile of an associated hard mask.

[0241] It should be noted that the above methods describe possible implementations, and the operations and steps can be rearranged or otherwise modified, and other implementations are possible. Furthermore, parts from two or more methods can be combined.

[0242] The information and signals described herein can be represented using any of a variety of different techniques and technologies. For example, the data, instructions, commands, information, signals, bits, symbols, and pieces referred to throughout the foregoing description can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof. Some figures may illustrate signals as single signals; however, those skilled in the art will understand that signals can represent signal buses, where buses can have various bit widths.

[0243] The terms "electronic communication," "conductive contact," "connection," and "coupling" can refer to the relationship between components that support signal flow between them. Components are considered to be in electronic communication (or electrically connected, connected, or coupled to) each other if there is any conductive path between them that can readily support signal flow between them. At any given time, the conductive path between components that are electronically connected (or electrically contacted, connected, or coupled to) each other can be open or closed, depending on the operation of the device including the connecting components. The conductive path between connected components can be a direct conductive path between the components, or it can be an indirect conductive path that may include intermediate components (e.g., switches, transistors, or other components). In some examples, for instance, using one or more intermediate components such as switches or transistors, the signal flow between connected components can be interrupted for a period of time.

[0244] The devices discussed herein, including optical components, can be formed on semiconductor substrates such as silicon, germanium, silicon-germanium alloys, gallium arsenide, gallium nitride, etc. In some examples, the substrate is a semiconductor wafer. In other examples, the substrate can be a silicon-on-insulator (SOI) substrate, such as silicon-on-glass (SOG) or silicon-on-sapphire (SOP), or an epitaxial layer of semiconductor material on another substrate. The conductivity of the substrate or subregions of the substrate can be controlled by doping using various chemicals, including but not limited to phosphorus, boron, or arsenic. Doping can be performed during the initial formation or growth of the substrate by ion implantation or by any other doping method.

[0245] The description set forth herein, taken in conjunction with the accompanying drawings, describes exemplary configurations and does not represent all examples that can be implemented or that are within the scope of the claims. The term "exemplary" as used herein means "serving as an example, instance, or illustration," and not "preferred" or "superior to other examples." The detailed description includes specific details to provide an understanding of the described techniques. However, these techniques can be practiced without these specific details. In some instances, well-known structures and apparatuses are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0246] In the accompanying drawings, similar components or features may have the same component symbol. Furthermore, parts of the same type can be distinguished by the letter following the component symbol, which identifies similar parts. If only the first component symbol is used in the specification, its description applies to any similar parts having the same first component symbol, regardless of the last letter.

[0247] The various illustrative blocks and modules described herein can be used with a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, intended to perform the functions described herein. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other combination of such configurations.

[0248] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored on or transmitted via a computer-readable medium as one or more instructions or code. Other examples and implementations are within the scope of this disclosure and the appended disclosures. For example, due to the nature of software, the functions described above can be implemented using software executed by a processor, hardware, firmware, hardwired, or any combination thereof. Features implementing the functions can also be physically located in various locations, including distributed, such that different parts of the functions are implemented at different physical locations. Additionally, as used herein, including in the claims, the word “or” used in the list of items (e.g., a list of items beginning with phrases such as “at least one” or “one or more”) signifies an inclusive list, for example, a list of at least one of A, B, or C signifies A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Moreover, as used herein, the phrase “based on” should not be construed as a reference to a closed set of conditions. For example, an exemplary step described as “based on condition A” can be based on both condition A and condition B without departing from the scope of this disclosure. In other words, as used in this article, the phrase “based on” should be interpreted in the same way as the phrase “at least partially based on”.

[0249] Computer-readable media includes non-transitory computer-readable media and communication media, with communication media including any medium that facilitates the transfer of computer programs from one place to another. Non-transitory storage media can be any available medium accessible by a general-purpose or special-purpose computer. By way of example and without limitation, non-transitory computer-readable media may include random access memory (RAM), read-only memory (ROM), electronically erasable programmable read-only memory (EEPROM), optical disc read-only memory (CD-ROM) or other optical disc storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures accessible by a general-purpose or special-purpose computer (or a general-purpose or special-purpose processor). Furthermore, any link is appropriately referred to as computer-readable media. For example, the definition of media includes coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave. The disks and optical discs used in this article include CDs, laser discs, optical discs, digital multifunction discs (DVDs), floppy disks, and Blu-ray discs. Disks typically copy data magnetically, while optical discs copy data optically using lasers. Combinations of the aforementioned are also included within the scope of computer-readable media.

[0250] According to one embodiment, an optical system includes:

[0251] (i) Multiple input optical fibers;

[0252] (ii) An optical mode multiplexer coupled to an input optical fiber, the optical mode multiplexer comprising multiple metamaterial structures having a length l and forming at least one first-order metamaterial having a length L and a width W, and

[0253] a. At least one stage of metamaterial is located on the surface of the optical mode multiplexer / demultiplexer facing the input fiber, and the at least one stage of metamaterial is oriented at an angle between 60 degrees and 120 degrees relative to the axis of the input fiber; and

[0254] b. The metasurface is configured to receive a first optical signal having a first mode from at least one of a plurality of input optical fibers and to convert the first mode into a different mode.

[0255] According to one embodiment, an optical system includes:

[0256] (i) Multiple input optical fibers;

[0257] (ii) At least one output optical fiber;

[0258] (iii) An optical mode multiplexer, coupled to an input fiber and coupled to at least one output fiber, the optical mode multiplexer comprising multiple metamaterial structures having a length l and forming at least one first-order metamaterial having a length L and a width W, and

[0259] a. At least one metamaterial is located on the surface of the optical mode multiplexer facing at least one output fiber, and the length L of the at least one metamaterial is oriented at an angle between 60 degrees and 120 degrees relative to the axis of the at least one output fiber; and

[0260] b. The metasurface is configured to receive a first optical signal having a first mode from at least one of a plurality of input optical fibers and to convert the first mode into a different mode.

[0261] According to some embodiments, the optical mode multiplexer is directly coupled to the input fiber without a focusing lens between them. According to some embodiments, at least one stage of metamaterial is oriented at an angle between 70 and 110 degrees (e.g., between 80 and 100 degrees, or between 84 and 97 degrees) relative to (i) the axis of the input fiber; or (ii) the axis of at least one output fiber (e.g., at least one multi-core or at least one multimode fiber). According to some embodiments, at least one stage of metamaterial is oriented at an angle of 89 to 91 degrees relative to the axis of the input fiber or the axis of at least one output fiber. According to some embodiments, at least one stage of metamaterial is not oriented at a right angle relative to the axis of the input fiber. According to some embodiments, at least one stage of metamaterial is oriented at a right angle (90 degrees) relative to the axis of the input fiber. According to some specific embodiments, 100mm > L > 10μm and 100mm > W > 10μm, for example 50mm > L > 50μm and 50mm > W > 50μm, or 50mm > L > 200μm and 50mm > W > 200μm.

[0262] According to some specific embodiments, the optical system includes at least one multi-core or multimode fiber optically coupled to an optical mode multiplexer, wherein the at least one multi-core or multimode fiber receives the output beam from the optical mode multiplexer / demultiplexer. According to some specific embodiments, at least one multi-core or multimode fiber is coupled to and receives different optical modes from the optical mode multiplexer, without placing any focusing lens between the optical mode multiplexer and the at least one multi-core or multimode fiber.

[0263] In some embodiments, the input fiber is directly attached to the input surface of the optical multiplexer. In other embodiments, the input fiber is coupled to the optical mode multiplexer via a connector or coupler.

[0264] According to some specific embodiments, each of the plurality of metamaterial structures has a length l, wherein 5 μm > l > 100 nm, for example, 10 μm > l > 50 nm. According to some specific embodiments, each of the plurality of metamaterial structures has a length l, wherein 5 μm > l > 100 nm, and the length orientation of the plurality of metamaterial structures is perpendicular to the substrate. According to some specific embodiments, each of the plurality of metamaterial structures has a length l, wherein 5 μm > l > 100 nm (e.g., between 200 nm and 5 μm), and the length orientation of the plurality of metamaterial structures is parallel to the axis of the input optical fiber. According to at least some specific embodiments, the plurality of metamaterial structures are arranged in an array of at least 3×3. According to at least some specific embodiments, the plurality of metamaterial structures are arranged in an array of at least 3×3. According to some specific embodiments, at least one level of metamaterial comprises at least 1000 metamaterial structures (e.g., at least 1,000,000 metamaterial structures).

[0265] According to some specific embodiments, an optical system includes:

[0266] (i) N input optical fibers, wherein the input optical fibers are single-mode optical fibers and N≥2;

[0267] (ii) An optical mode multiplexer or demultiplexer coupled to an input fiber and comprising M metamaterial levels, where M≥2;

[0268] (iii) and at least one multi-core or multimode fiber, the at least one multi-core or multimode fiber being coupled to an optical mode multiplexer or demultiplexer, wherein the optical mode multiplexer or demultiplexer is configured to convert a single-mode input received from an input fiber into N different spatial modes and transmit them through the multi-core or multimode fiber.

[0269] (iv) An optical mode multiplexer or demultiplexer comprises multiple metamaterial structures having a length l, and forms at least one first-order metamaterial having a length L and a width W, and

[0270] a. At least one metamaterial is located on the surface of the optical mode multiplexer facing the input fiber and / or at least one multi-core or multimode fiber, such that the at least one metamaterial faces the input fiber, and the length L of the at least one metamaterial is oriented at an angle between 60 degrees and 120 degrees relative to the axis of the input fiber or the axis of at least one multi-core or multimode fiber; and

[0271] b. The metasurface is configured to receive a first optical signal having a first mode from at least one of a plurality of input optical fibers and to convert the first mode into a different mode.

[0272] According to some specific embodiments, an optical system includes:

[0273] (i) N input optical fibers, where the input optical fibers are single-mode optical fibers and N≥2;

[0274] (ii) An optical mode multiplexer or demultiplexer coupled to an input fiber and comprising M metamaterial levels, where M≥2;

[0275] (iii) and at least one multi-core or multimode fiber, the at least one multi-core or multimode fiber being coupled to an optical mode multiplexer or demultiplexer, wherein the optical mode multiplexer or demultiplexer is configured to convert a single-mode input received from an input fiber into N different spatial modes and transmit them through the multi-core or multimode fiber.

[0276] (iv) An optical mode multiplexer or demultiplexer comprises multiple metamaterial structures having a length l, and forms at least one first-order metamaterial having a length L and a width W, and

[0277] a. At least one metamaterial is located on the surface of the optical mode multiplexer facing at least one multi-core or multimode fiber, such that the at least one metamaterial faces the input fiber, and the length L of the at least one metamaterial is oriented at an angle between 60 degrees and 120 degrees relative to the axis of the input fiber or the axis of one of the multi-core or multimode fibers; and

[0278] b. The metasurface is configured to receive a first optical signal having a first mode from at least one of a plurality of input optical fibers and to convert the first mode into a different mode.

[0279] An optical system comprising:

[0280] (i) N input optical fibers, wherein the input optical fibers are single-mode optical fibers and N≥2;

[0281] (ii) An optical mode multiplexer or demultiplexer coupled to an input fiber and comprising M metamaterial levels, where M≥2;

[0282] (iii) and at least one multi-core or multimode fiber, the at least one multi-core or multimode fiber being coupled to an optical mode multiplexer or demultiplexer, wherein the optical mode multiplexer or demultiplexer is configured to convert a single-mode input received from an input fiber into N different spatial modes and transmit them through the multi-core or multimode fiber.

[0283] (iv) An optical mode multiplexer or demultiplexer comprises multiple metamaterial structures having a length l, and forms at least one level metamaterial having a length L and a width W, and

[0284] a. At least one metamaterial is located on the surface of the optical mode multiplexer facing at least one multi-core or multimode fiber, such that the at least one metamaterial faces the input fiber, and the length L of the at least one metamaterial is oriented at an angle between 60 degrees and 120 degrees relative to the axis of the input fiber; and

[0285] The metasurface is configured to receive a first optical signal having a first mode from at least one of a plurality of input optical fibers and to convert the first mode into a different mode.

[0286] According to some specific embodiments, an optical system includes:

[0287] (i) Multiple input optical fibers;

[0288] (ii) An optical mode multiplexer / demultiplexer, coupled to an input optical fiber, comprising multiple metamaterial structures arranged in an A×B array, wherein A≥3 and B≥3, the metamaterial structures forming at least one level of metamaterial, and

[0289] a. At least one level of metamaterial is located on the surface of the optical mode multiplexer / demultiplexer, such that the plane of the metamaterial is oriented at an angle between 60 and 120 degrees relative to the axis of the input fiber; and

[0290] b. The metasurface is configured to receive a first optical signal having a first mode from at least one of a plurality of input optical fibers and to convert the first mode into a different mode.

[0291] According to some specific embodiments, A ≥ 5, B ≥ 5, and the number of multiple metamaterial structures is greater than 500. According to some specific embodiments, A ≥ 5, B ≥ 5, and the number of multiple metamaterial structures is greater than 1000 (e.g., greater than 10000 or greater than 100000). According to some specific embodiments, A ≥ 5, B ≥ 5, and the number of multiple metamaterial structures is greater than 500. According to some specific embodiments, A ≥ 5, B ≥ 5, and the number of multiple metamaterial structures is greater than 1000 (e.g., greater than 10000 or greater than 100000, or even greater than 1000000). According to some specific embodiments, A ≥ 10, B ≥ 10, and the number of multiple metamaterial structures is greater than 1000. According to some specific embodiments, A ≥ 10, B ≥ 10, and the number of multiple metamaterial structures is greater than 1000 (e.g., greater than 10000 or greater than 100000). According to some specific embodiments, A ≥ 100, B ≥ 100, and the number of multiple metamaterial structures is greater than 1,000,000. According to some specific embodiments, 1,000,000 > A ≥ 10; 1,000,000 > B ≥ 10; and the number of multiple metamaterial structures is greater than 1,000,000 (e.g., not less than 10,000,000).

[0292] According to some specific embodiments, the mode multiplexer / demultiplexer includes a substrate with a thickness >5 μm (e.g., a thickness >20 μm, or even >100 μm).

[0293] An apparatus may include: a first substrate, the first substrate being transparent; a first metamaterial stage, the first metamaterial stage being positioned adjacent to or in contact with the first substrate; and a second metamaterial stage, the second metamaterial stage being positioned adjacent to or in contact with the first substrate, the first metamaterial stage and the second metamaterial stage being configured to: receive a second optical signal having a second mode via a second optical communication link; generate a third optical signal having a third mode by shifting a first phase profile of the first optical signal; generate a fourth optical signal having a fourth mode by shifting a second phase profile of the second optical signal; and transmit the third optical signal and the fourth optical signal via a third optical communication link, the third optical communication link including a multimode optical communication link.

[0294] In some examples, the first metamaterial stage can be configured to shift a first phase profile of the first optical signal and a second phase profile of the second optical signal, and output the first shifted optical signal and the second shifted optical signal, and the second metamaterial stage can be configured to shift a third phase profile of the first shifted optical signal and a fourth phase profile of the second shifted optical signal, and output the third optical signal and the fourth optical signal.

[0295] The description herein is provided to enable those skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of this disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but should be given the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. An optical system comprising: (i) Multiple input optical fibers; (ii) An optical mode multiplexer / demultiplexer coupled to the input optical fiber, the optical mode multiplexer / demultiplexer comprising a plurality of metamaterial structures having a length l and forming at least one first-order metamaterial having a length L and a width W, and a. The at least one metamaterial is located on the surface of the optical mode multiplexer / demultiplexer facing the input fiber, and the length L of the at least one metamaterial is oriented at an angle between 60 and 120 degrees relative to the axis of the input fiber; and b. The at least one-level metamaterial is configured to receive a first optical signal having a first mode from at least one of the plurality of input optical fibers and to convert the first mode into a different mode.

2. The optical system of claim 1, wherein the at least one metamaterial is oriented at an angle between 70 and 110 degrees relative to the axis of the input optical fiber.

3. The optical system of claim 2, wherein the at least one metamaterial is oriented at an angle between 80 and 100 degrees relative to the axis of the input optical fiber.

4. The optical system of claim 1, wherein the at least one metamaterial is not oriented at a right angle relative to the axis of the input optical fiber.

5. The optical system of claim 1, wherein the at least one metamaterial is oriented at an angle of 89 to 91 degrees relative to the axis of the input optical fiber.

6. The optical system of claim 1, wherein the at least one metamaterial is oriented at a right angle relative to the axis of the input optical fiber.

7. The optical system of claim 1, further comprising at least one multi-core or multimode fiber optically coupled to the optical mode multiplexer, wherein the at least one multi-core or multimode fiber receives an output beam from the optical mode multiplexer / demultiplexer.

8. The optical system of claim 2, wherein the at least one multi-core or multimode fiber is coupled to the optical mode multiplexer / demultiplexer and receives the different modes from the optical mode multiplexer / demultiplexer, without any focusing lens between the at least one multi-core or multimode fiber and the optical mode multiplexer / demultiplexer.

9. The optical system of claim 1, wherein the input optical fiber is directly attached to the input surface of the optical mode multiplexer / demultiplexer.

10. The optical system of claim 1, wherein the input optical fiber is coupled to the optical mode multiplexer / demultiplexer via a connector interface.

11. The optical system of claim 1, wherein each of the plurality of metamaterial structures has the length l, wherein Furthermore, the length orientation of the plurality of metamaterial structures is perpendicular to the substrate of the optical mode multiplexer / demultiplexer.

12. The optical system of claim 1, wherein each of the plurality of metamaterial structures has the length l, wherein Furthermore, the length orientation of the plurality of metamaterial structures is parallel to the axis of the input optical fiber.

13. The optical system of claim 1, wherein ,and .

14. An optical system comprising: (i) N input optical fibers, wherein the input optical fibers are single-mode optical fibers and ; (ii) An optical mode multiplexer / demultiplexer, coupled to the input optical fiber and comprising M metamaterial levels, wherein... ; (iii) and at least one multi-core or multimode fiber coupled to the optical mode multiplexer / demultiplexer, wherein the optical mode multiplexer / demultiplexer is configured to convert a single-mode input received from the input fiber into N different spatial modes and transmit them through the multi-core or multimode fiber. (iv) The optical mode multiplexer / demultiplexer comprises multiple metamaterial structures having a length l, and forms at least one first-order metamaterial having a length L and a width W, and a. The at least one metamaterial is located on the surface of the optical mode multiplexer or demultiplexer facing the input optical fiber, and the length L of the at least one metamaterial is oriented at an angle between 60 degrees and 120 degrees relative to the axis of the input optical fiber; as well as The at least one-level metamaterial is configured to receive a first optical signal having a first mode from at least one of the plurality of input optical fibers, and to convert the first mode into a different mode.

15. The optical system of claim 14, wherein the optical mode multiplexer / demultiplexer is directly coupled to the input optical fiber, and there is no focusing lens between them.

16. The optical system of claim 14, wherein the metamaterial level comprises a plurality of metamaterial structures having a length l. .

17. An optical system comprising: (iii) Multiple input optical fibers; (iv) An optical mode multiplexer / demultiplexer, coupled to the input optical fiber, the optical mode multiplexer / demultiplexer comprising: Multiple metamaterial structures arranged in an array, among which and The metamaterial structure forms at least one level metamaterial, and a. The at least one-stage metamaterial is located on the surface of the optical mode multiplexer / demultiplexer, such that the plane of the at least one-stage metamaterial is oriented at an angle between 60 degrees and 120 degrees relative to the axis of the input optical fiber; and b. The at least one-level metamaterial is configured to receive a first optical signal having a first mode from at least one of the plurality of input optical fibers and to convert the first mode into a different mode.

18. The optical system of claim 17, wherein the at least one metamaterial is oriented at an angle between 70 and 110 degrees relative to the axis of the input optical fiber.

19. The optical system of claim 17, wherein the metamaterial structure has a length l, and .

20. The optical system of claim 17, wherein , Furthermore, the number of metamaterial structures exceeds 500.

21. The optical system of claim 17, wherein , Furthermore, the number of metamaterial structures exceeds 1000.

22. The optical system of claim 17, wherein , Furthermore, the number of the plurality of metamaterial structures is greater than 10,000.

23. The optical system of claim 17, wherein , Furthermore, the number of the plurality of metamaterial structures exceeds 100,000.

24. The optical system of claim 17, wherein , Furthermore, the number of the plurality of metamaterial structures exceeds 1,000,000.

25. The optical system of claim 17, wherein , Furthermore, the number of the plurality of metamaterial structures exceeds 1,000,000.

26. The optical system of claim 17, wherein: ; Furthermore, the number of the plurality of metamaterial structures exceeds 1,000,000.

27. The optical system of claim 17, wherein the optical mode multiplexer / demultiplexer comprises a thickness The substrate.

28. The optical system of claim 17, wherein the optical mode multiplexer / demultiplexer includes a thickness The substrate.

29. The optical system of claim 17, wherein the optical mode multiplexer / demultiplexer comprises a thickness The substrate.

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