A hollow core optical fiber guide is provided that comprises a body for reflecting light comprising a first end, a second end, a longitudinal dimension extending between the first end and the second end, an inner sidewall, an outer sidewall, and a transverse dimension extending radially between the inner sidewall and the outer sidewall, wherein the body comprises a plurality of optically dielectric material and each of the plurality of dielectric material having a different refractive index; and a light guiding core region disposed within the body.

A technique for fabricating a hollow core optical fiber with a controllable core region (in terms of diameter) is based upon regulating conditions (gas flow, volume, and/or temperature) within the hollow core region during the fiber draw process. The introduction of a gas, or any change in volume or temperature of the hollow core region, allows for the diameter of the hollow core region to self-regulate as a multistructured core rod (MCR) is drawn down into the final hollow core optical fiber structure. This self-regulation provides a core region having a diameter that selected and then stabilized for the duration of the draw process. The inventive process is also useful in controlling the diameter of any selected hollow region of an MCR including, but not limited to, shunts and corner capillaries disposed around the core region.

A hollow core fiber (HCF) link is characterized by structural properties selected to support and sustain light propagation in a fundamental mode and in at least one higher-order mode. Connected to a proximal end of the HCF link, there is a mode coupler configured to couple a data signal into the fundamental mode and to couple an obfuscating signal into the at least one higher-order mode for simultaneous propagation of the data signal and the obfuscating signal on the HCF link, where the obfuscating signal substantially overlaps the data signal in spectral content. At a distal end of the HCF link, there is a mode splitter configured to split a first optical signal detected in the fundamental mode from a second optical signal detected in the at least one higher-order mode.

A patch cord for transmitting between a single mode fiber (SMF) and a multi-mode fiber (MMFs) has a MMF, SMF, and a photonic crystal fiber (PCF) with a hollow core placed between the SMF and MMF. A mode field diameter (MFD) of the PCF hollow core section is in the range of 16 to 19 microns, the length of the PCF is between 1 cm to 10 cm, the MMF has 502 microns core diameter, the SMF has a 6-9 microns core diameter, and the coupling between the PCF mode to the MMF fundamental mode is maximized.

The disclosed embodiments generally relate to extruding multiple layers of micro- to nano-polymer layers in a tubular shape. In particular, the aspects of the disclosed embodiments are directed to a method for producing a Bragg reflector comprising co-extrusion of micro- to nano-polymer layers in a tubular shape.

An electromagnetic wave transmission cable for transmitting an electromagnetic wave comprises a hollow waveguide tube and a foamed resin member. The hollowing waveguide tube includes a hollow dielectric layer formed in a tubular shape. The foamed resin member is provided over a predetermined length in a longitudinal direction of the hollow waveguide tube and covers a surface of the dielectric layer to surround an outer periphery of the hollow waveguide tube.

The rolled photonic fibers presents two codependent, technologically exploitable features for light and color manipulation: regularity on the nanoscale that is superposed with microscale cylindrical symmetry, resulting in wavelength selective scattering of light in a wide range of directions. The bio-inspired photonic fibers combine the spectral filtering capabilities and color brilliance of a planar Bragg stack compounded with a large angular scattering range introduced by the microscale curvature, which also decreases the strong directional chromaticity variation usually associated with flat multilayer reflectors. Transparent and elastic synthetic materials equip the multilayer interference fibers with high reflectance that is dynamically tuned by longitudinal mechanical strain. A two-fold elongation of the elastic fibers results in a shift of reflection peak center wavelength of over 200 nm.

Air core optical fiber structures in which the cladding is composed of an engineered optical metamaterial having a refractive index less than unity for at least one specific wavelength band and provides for total internal reflection of optical energy between the air core and metamaterial cladding. According to certain examples, a method of guiding optical energy includes constructing a hollow core optical fiber with an all-dielectric optical metamaterial cladding, coupling optical energy into the optical fiber having an operating wavelength near a resonance of the metamaterial cladding, and guiding the optical energy within the hollow core optical fiber by total internal reflection.

An air-gap HCF connector termination method and connector assembly for factory and field connector assembly termination for patch cables and trunk cables made from HCF, where in multitude of mechanisms can facilitate air-gap between the first and second HCF fiber end-faces, comprising preparing the HCF end-faces using appropriate cleaving methods including mechanical, ultrasonic and laser cleaving, such that the air-gap separation between first and second HCF's can be anywhere between 0.5-100 microns, where reflection at the connector interface is low with RL>35 dB, due to HCF propagation mode effective index matching with index of air.

Air core optical fiber structures in which the cladding is composed of an engineered optical metamaterial having a refractive index less than unity for at least one specific wavelength band and provides for total internal reflection of optical energy between the air core and metamaterial cladding. According to certain examples, a method of guiding optical energy includes constructing a hollow core optical fiber with an all-dielectric optical metamaterial cladding, coupling optical energy into the optical fiber having an operating wavelength near a resonance of the metamaterial cladding, and guiding the optical energy within the hollow core optical fiber by total internal reflection.