A capillary array includes a capillary region, including capillaries of a first glass, which are disposed in an axis-parallel manner. A low refractive index layer is disposed on an inner wall of each of the capillaries, the refractive index of each low refractive index layer being less than a refractive index of a liquid scintillator. A second glass material is disposed between adjacent capillaries. A softening point of the first glass is T.sub.1, a softening point of second glass is T.sub.2, and a value of T.sub.1 minus T.sub.2 is in a range from 30 C. to 50 C. A thermal expansion coefficient of the first glass is .sub.1. An edge covering region is disposed on an outer side of the capillary region and makes contact with an outer side face of the capillary region, wherein a material of the edge covering region is a third glass.

A capillary array includes a capillary region, including capillaries of a first glass, which are disposed in an axis-parallel manner. A low refractive index layer is disposed on an inner wall of each of the capillaries, the refractive index of each low refractive index layer being less than a refractive index of a liquid scintillator. A second glass material is disposed between adjacent capillaries. A softening point of the first glass is T.sub.1, a softening point of second glass is T.sub.2, and a value of T.sub.1 minus T.sub.2 is in a range from 30 C. to 50 C. A thermal expansion coefficient of the first glass is .sub.1. An edge covering region is disposed on an outer side of the capillary region and makes contact with an outer side face of the capillary region, wherein a material of the edge covering region is a third glass.

Optical waveguide cores having refractive index profiles that vary angularly about a propagation axis of the core can provide single-mode operation with larger core diameters than conventional waveguides. An optical waveguide includes a core that extends along a propagation axis and has a refractive index profile that varies angularly about the propagation axis. The optical waveguide also includes a cladding disposed about the core and extending along the propagation axis. The refractive index profile of the core varies angularly along a length of the propagation axis.

Optical waveguide cores having refractive index profiles that vary angularly about a propagation axis of the core can provide single-mode operation with larger core diameters than conventional waveguides. An optical waveguide includes a core that extends along a propagation axis and has a refractive index profile that varies angularly about the propagation axis. The optical waveguide also includes a cladding disposed about the core and extending along the propagation axis. The refractive index profile of the core varies angularly along a length of the propagation axis.

The present application discloses a method for fabricating a fiber optic image inverter with an ultra-short twister. The method includes: drawing a glass rod with a low refractive index and a high strain point temperature into a surrounding pipe fiber; drawing a glass rod with a high refractive index and a high transmittance into a filling glass fiber, and then drawing into a casing pipe absorption fiber; uniformly surrounding an outer side of a cladding glass pipe with the surrounding pipe fiber, and matching a core glass rod and the cladding glass pipe to be drawn into a mono fiber; and then performing fabrication of a multi fiber, fabrication of a multi-multi fiber, heat press fusion and twisting operation in sequence. The fiber optic image inverter with an ultra-short twister with a high resolution and a high contrast and clear imaging is obtained and applied in a low-light-level image intensifier.

The present application discloses a method for fabricating a fiber optic image inverter with an ultra-short twister. The method includes: drawing a glass rod with a low refractive index and a high strain point temperature into a surrounding pipe fiber; drawing a glass rod with a high refractive index and a high transmittance into a filling glass fiber, and then drawing into a casing pipe absorption fiber; uniformly surrounding an outer side of a cladding glass pipe with the surrounding pipe fiber, and matching a core glass rod and the cladding glass pipe to be drawn into a mono fiber; and then performing fabrication of a multi fiber, fabrication of a multi-multi fiber, heat press fusion and twisting operation in sequence. The fiber optic image inverter with an ultra-short twister with a high resolution and a high contrast and clear imaging is obtained and applied in a low-light-level image intensifier.

The present application discloses a method for fabricating a fiber optic image inverter with an ultra-short twister. The method includes: drawing a glass rod with a low refractive index and a high strain point temperature into a surrounding pipe fiber; drawing a glass rod with a high refractive index and a high transmittance into a filling glass fiber, and then drawing into a casing pipe absorption fiber; uniformly surrounding an outer side of a cladding glass pipe with the surrounding pipe fiber, and matching a core glass rod and the cladding glass pipe to be drawn into a mono fiber; and then performing fabrication of a multi fiber, fabrication of a multi-multi fiber, heat press fusion and twisting operation in sequence. The fiber optic image inverter with an ultra-short twister with a high resolution and a high contrast and clear imaging is obtained and applied in a low-light-level image intensifier.

The present application discloses a method for fabricating a fiber optic image inverter with an ultra-short twister. The method includes: drawing a glass rod with a low refractive index and a high strain point temperature into a surrounding pipe fiber; drawing a glass rod with a high refractive index and a high transmittance into a filling glass fiber, and then drawing into a casing pipe absorption fiber; uniformly surrounding an outer side of a cladding glass pipe with the surrounding pipe fiber, and matching a core glass rod and the cladding glass pipe to be drawn into a mono fiber; and then performing fabrication of a multi fiber, fabrication of a multi-multi fiber, heat press fusion and twisting operation in sequence. The fiber optic image inverter with an ultra-short twister with a high resolution and a high contrast and clear imaging is obtained and applied in a low-light-level image intensifier.

An optical fiber bundle structure includes: a plurality of optical fiber core wires; and a capillary, wherein each of the optical fiber core wires includes a glass fiber portion including a core and a clad, and a resin coated portion, the glass fiber portions are inserted in the capillary, and d2/d1 is equal to or larger than 0.57 and smaller than 1, where d1 is a diameter of the core of each of the glass fiber portions in a rear end portion of the capillary and d2 is a diameter of the core of each of the glass fiber portions in a distal end portion of the capillary.

An optical fiber bundle structure includes: a plurality of optical fiber core wires; and a capillary, wherein each of the optical fiber core wires includes a glass fiber portion including a core and a clad, and a resin coated portion, the glass fiber portions are inserted in the capillary, and d2/d1 is equal to or larger than 0.57 and smaller than 1, where d1 is a diameter of the core of each of the glass fiber portions in a rear end portion of the capillary and d2 is a diameter of the core of each of the glass fiber portions in a distal end portion of the capillary.