The present invention relates to an optical fiber (100) comprising a core region (102) having radius R1 and a cladding region (104) having a radius R3. In particular, the core region (102) is defined along a central longitudinal axis (110) and the cladding region (104) is defined along the central longitudinal axis (110) of the optical fiber (100). Moreover, the optical fiber (100) has a Mode Field Diameter in a range of 8.5+/−0.3 microns at a wavelength of 1310 nanometers, a micro-bending loss of less than equal to 0.5 dB/Km at a wavelength of 1550 nanometers, macro-bending loss of less than 1 dB/Km at a wavelength 1550 nanometers. Further, the optical fiber (100) has a diameter of less than 210 microns.

A method of categorizing single mode optical fibers, the method including determining one or more fiber properties of an optical fiber, the optical fiber being a single mode optical fiber at an operating wavelength of about 1310 nm. The method further including calculating a peak bandwidth wavelength of the optical fiber based on the one or more fiber properties, comparing the calculated peak bandwidth wavelength with a target peak bandwidth wavelength and based on the comparison, determining if the optical fiber meets a target modal bandwidth.

The optical fibers disclosed is a single mode optical fiber having a core region and a cladding region surrounding and directly adjacent to the core region. The core region can have a radius r.sub.1 in a range from 3.0 microns to 6.0 microns and a core volume V.sub.1 less than 6.0%-micron.sup.2. The cladding region can include a first outer cladding region and a second outer cladding region surrounding and directly adjacent to the first outer cladding region. The first outer cladding region can have a radius r.sub.4a, the second outer cladding region can have a radius r.sub.4b less than or equal to 65 microns and comprising silica based glass doped with titania. The disclosed single mode optical fiber can have a fiber cutoff wavelength λ.sub.CF less than 1530 nm.

According to embodiments, a method of making a microstructured glass article includes bundling M bare optical fibers in a fiber bundle, wherein M is an integer greater than 100. Thereafter, the fiber bundle may be inserted in a cavity of a soot preform. The soot preform may have a density of less than or equal to 1.5 g/cm.sup.3 and comprise silica-based glass soot. The soot preform and inserted fiber bundle may then be consolidated to form a microstructured glass article preform. The microstructured glass article preform may then be drawn into the microstructured glass article comprising M core elements embedded in a cladding matrix.

Disclosed herein is a method for measuring temperature via distributed temperature sensing comprising transmitting light through a fiber optic cable; detecting backscattered light in the fiber optic cable, wherein the backscattered light comprises an anti-Stokes band and a Stokes band; calculating a ratio between an intensity of the anti-Stokes band and an intensity of the Stokes band; and using the calculated ratio to determine a temperature being sensed in the fiber optic cable; wherein the fiber optic cable comprises, from the center to the periphery; a central core having a refractive index that decreases progressively from a center of the central core to an edge of the core, wherein the refractive index follows an alpha profile; wherein a bandwidth-length product of the multimode optical fiber has a value greater than 2000 MHz-km at 1550 nm.

A fiber optic cable includes a cable jacket having an outer surface defined by a cable jacket outer diameter J.sub.OD and an inner surface defined by a cable jacket inner diameter J.sub.ID; a plurality N of optical fibers, where N≥4, contained within the cable jacket and positioned a distance away from the cable jacket inner diameter, with each optical fiber having a core, a cladding surrounding the core, and at least one coating surrounding the core with the at least one coating having an outer coating diameter less than or equal to about 200 microns and wherein the cable jacket outer diameter J.sub.OD is less than or equal to 1 mm.

A multicore optical fiber includes an inner glass region having a plurality of core regions surrounded by a common outer cladding, the inner glass region further having at least one marker and an outer diameter in the range of 120 microns and 130 microns, wherein each core region is comprised of a germania-doped silica core and a fluorine-doped silica trench, wherein the trench volume of the fluorine-doped silica trench is greater than 50% Δ microns.sup.2. The fiber has an outer coating layer surrounding the inner glass region, the outer coating layer having a primary coating layer and a secondary coating layer with a diameter of the secondary coating layer equal to or less than 200 microns, wherein each core region has a mode field diameter greater than 8.2 microns at 1310 nm, a cable cutoff wavelength of less than 1260 nm, and zero dispersion wavelength of less than 1335 nm.

In some embodiments, an optical fiber transmission link, includes a length of dispersion compensating fiber (DCF), the dispersion compensating fiber coupled to a length of single-mode fiber (SMF) having a zero dispersion wavelength of 1300 nm to 1324 nm; wherein the optical fiber transmission link comprising the dispersion compensating fiber coupled to the single-mode fiber and operating at wavelengths between 1265 nm and 1375 nm increases maximum link lengths of the optical fiber transmission link by more than 60% as compared to the link length of the optical fiber transmission link with the single-mode fiber only; and wherein the maximum link length is calculated from the maximum allowed positive and negative accumulated dispersion at wavelengths between 1265 nm and 1375 nm.

According to embodiments, a method of making a micro structured glass article 100 includes bundling M bare optical fibers in a fiber bundle, wherein M is an integer greater than 100. Thereafter, the fiber bundle may be inserted in a cavity of a soot preform. The soot preform may have a density of less than or equal to 1.5 g/cm3 and comprise silica-based glass soot. The soot preform and inserted fiber bundle may then be consolidated to form a microstructured glass article preform. The micro structured glass article preform may then be drawn into the microstructured glass article 100 comprising M core elements 102 embedded in a cladding matrix 104.

A multi-core fiber includes: plural cores made of silica-based glass; and a cladding enclosing the plural cores and made of silica-based glass, the cladding having a refractive index lower than a maximum refractive index of the plural cores. Further, the multi-core fiber has a mode field diameter of 5.0 μm or larger at a wavelength of 1100 nm, the multi-core fiber provides single-mode propagation at the wavelength of 1100 nm, the multi-core fiber has a bending loss of 1 dB/turn or less at the wavelength of 1100 nm when the multi-core fiber is bent at a radius of 2 mm, and the multi-core fiber has a crosstalk between cores of −30 dB/km or less.