The present disclosure provides an optical fibre. The optical fibre includes a core extended from a central longitudinal axis to a first radius r1. Further, the optical fibre includes a first trench region extended from a second radius r2 to a third radius r3, a second trench region extended from the third radius r3 to a fourth radius r4 and a cladding region extended from the fourth radius r4 to a fifth radius r5.

The present disclosure provides an optical fibre. The optical fibre includes a core region, a primary trench region and a secondary trench region. The core region has a radius r.sub.1. In addition, the core region has a relative refractive index .sub.1. Further, the primary trench region has a relative refractive index .sub.3. Furthermore, the primary trench region has a curve parameter .sub.trench-1. Moreover, the secondary trench region has a relative refractive index .sub.4. Also, the secondary trench region has a curve parameter .sub.trench-2.

An optical fiber includes a glass fiber and a coating resin covering an outer periphery of the glass fiber. The glass fiber includes a core, an inner cladding, a trench, and an outer cladding. An outer diameter of the glass fiber is 99 m or larger and 101 m or smaller. An outer diameter of the coating resin is 160 m or larger and 170 m or smaller. A mode field diameter for light having a wavelength of 1310 nm is 7.2 m or larger and 8.2 m or smaller. Bending loss at a wavelength of 1550 nm when wound in a ring shape having a radius of 10 mm is 0.1 dB/turn or less. Bending loss at the wavelength of 1550 nm when wound in the ring shape having the radius of 7.5 mm is 0.5 dB/turn or less.

The disclosure provides optical fibers that exhibit low macrobend loss at 1550 nm at bend diameters between 10 mm and 40 mm. The relative refractive index profile of the fibers includes a trench cladding region with small depth, large width and a trench volume configured to minimize macrobend loss at large and small bend diameters. The optical fiber includes an outer cladding region that surrounds and is directly adjacent to the trench cladding region and an optional offset cladding region between the trench cladding region and the core region. In some embodiments, the trench cladding region has a relative refractive index that decreases monotonically from the inner radius to the outer radius. The monotonic decrease in relative refractive index may have a constant slope. The low macrobend loss at large and small diameters makes the optical fibers well suited for space-constrained deployment environments, such as data centers.

An optical fiber includes: a core; a depressed layer surrounding the core; and a cladding surrounding the depressed layer. A refractive index profile of the core is an -th power distribution having an index of 1.0 or more and 2.9 or less. A relative refractive index difference .sup. of the depressed layer with respect to the cladding has an absolute value |.sup.| that is 0.05% or more and 0.15% or less. A ratio r1/r2 of a radius r1 of the core to an outer radius r2 of the depressed layer is 0.35 or more and 0.60 or less. A cable cutoff wavelength cc of 22 m is less than 1.26 m. A mode field diameter at a wavelength of 1.31 inn is larger than 8.6 inn and smaller than 9.5 m.

A single mode optical fiber includes: (i) a silica based core having a refractive index profile with an alpha () between 1.8 and 200, a relative refractive index .sub.1max %, and an outer radius r.sub.1, wherein 7 microns>r.sub.14.5 microns, the core further comprising silica doped with chlorine, wherein the maximum chlorine concentration in the core is greater than 0.5 wt %; and wherein
1.40<X<1.7 where X=[(2n.sub.1(2.sub.1max % r.sub.1.sup.2).sup.1/2/V.sub.c)+(0.0028*V.sub.m)],
n.sub.1 is maximum refractive index of the core, V.sub.m is moat volume, and V.sub.c is a function of core alpha () and (ii) an outer cladding region surrounding the first cladding region, the outer cladding region having a relative refractive index .sub.4% such that .sub.1max>.sub.4%.

An optical fiber includes a glass fiber and a coating resin covering an outer periphery of the glass fiber. The glass fiber includes a core, an inner cladding, a trench, and an outer cladding. An outer diameter of the glass fiber is 99 m or larger and 101 m or smaller. An outer diameter of the coating resin is 160 m or larger and 170 m or smaller. A mode field diameter for light having a wavelength of 1310 nm is 7.2 m or larger and 8.2 M or smaller. Bending loss at a wavelength of 1550 nm when wound in a ring shape having a radius of 10 mm is 0.1 dB/turn or less. Bending loss at the wavelength of 1550 nm when wound in the ring shape having the radius of 7.5 mm is 0.5 dB/turn or less.

The optical fiber offered is capable of not only restraining the attenuation due to glass defects, but also reducing the increase of manufacturing cost. The optical fiber is made of silica glass and includes a core and a cladding. The cladding encloses the core and has a refractive index smaller than that of the core. When the core is divided into inner core and outer core at half of the radius of the core, the average chlorine concentration of the inner core is larger than that of the outer core. The core includes any of the alkali metal group.

The optical fiber offered is capable of not only restraining the attenuation due to glass defects, but also reducing the increase of manufacturing cost. The optical fiber is made of silica glass and includes a core and a cladding. The cladding encloses the core and has a refractive index smaller than that of the core. When the core is divided into inner core and outer core at half of the radius of the core, the average chlorine concentration of the inner core is larger than that of the outer core. The core includes any of the alkali metal group.

An optical fiber includes (i) a chlorine doped silica based core having a core alpha (Core.sub.)4, a radius r.sub.1, and a maximum refractive index delta .sub.1max % and (ii) a cladding surrounding the core. The cladding surrounding the core includes a) a first inner cladding region adjacent to and in contact with the core and having a refractive index delta .sub.2, a radius r.sub.2, and a minimum refractive index delta .sub.2min such that .sub.2min<.sub.1max, b) a second inner cladding adjacent to and in contact with the first inner cladding having a refractive index .sub.3, a radius r.sub.3, and a minimum refractive index delta .sub.3min such that .sub.3min<.sub.2, and c) an outer cladding region surrounding the second inner cladding region and having a refractive index .sub.5, a radius r.sub.max, and a minimum refractive index delta .sub.3min such that .sub.3min<.sub.2. The optical fiber has a mode field diameter MFD at 1310 of 9 microns, a cable cutoff of 1260 nm, a zero dispersion wavelength of 1300 nmzero dispersion wavelength 1324 nm, and a macrobending loss at 1550 nm for a 20 mm mandrel of less than 0.75 dB/turn.