A multicore optical fiber includes two or more cores, a common interior cladding surrounding the two or more cores, and a common exterior cladding surrounding the common interior cladding. The common exterior cladding has a lower relative refractive index than the common interior cladding and reduces tunneling losses from the cores. The reduced tunneling loss allows placement of cores closer to the edge of the fiber, thus providing multicore optical fibers having higher core count for a given fiber diameter. Separation between cores is controlled to minimize crosstalk.

A multicore optical fiber includes two or more cores, a common interior cladding surrounding the two or more cores, and a common exterior cladding surrounding the common interior cladding. The common exterior cladding has a lower relative refractive index than the common interior cladding and reduces tunneling losses from the cores. The reduced tunneling loss allows placement of cores closer to the edge of the fiber, thus providing multicore optical fibers having higher core count for a given fiber diameter. Separation between cores is controlled to minimize crosstalk.

An optical combiner includes: a plurality of first input optical fibers that each include a core; a bridge fiber that includes a bridge input surface connected to the cores of the plurality of first input optical fibers, a diameter reduction portion having a diameter that decreases away from the bridge input surface along an optical axis of the optical combiner, and a bridge output surface located opposite to the bridge input surface along the optical axis; an intermediate optical fiber that includes a core connected to the bridge output surface of the bridge fiber; a second input optical fiber that includes a core; and an output optical fiber that includes a first optical waveguide connected to the core of the intermediate optical fiber, and a second optical waveguide connected to the core of the second input optical fiber.

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.

A multicore optical fiber includes two or more cores, a common interior cladding surrounding the two or more cores, and a common exterior cladding surrounding the common interior cladding. The common exterior cladding has a lower relative refractive index than the common interior cladding and reduces tunneling losses from the cores. The reduced tunneling loss allows placement of cores closer to the edge of the fiber, thus providing multicore optical fibers having higher core count for a given fiber diameter. Separation between cores is controlled to minimize crosstalk.

The present disclosure provides an optical fiber (100). The optical fiber (100) includes a core region (102). The core region (102) is defined by a region around central longitudinal axis (112) of the optical fiber (100). In addition, the core region (100) has a first annular region (106). The first annular region (106) is defined from the central longitudinal axis (112) to a first radius from the central longitudinal axis. Moreover, the core region (102) has a second annular region (108). The second annular region (108) is defined from the first radius to a second radius. Further, the core region (102) has a third annular region (110). The third annular region (110) is defined from the second radius to a third radius. Also, the optical fiber (100) includes a cladding (104). The cladding region (104) has a fourth radius.

An optical fiber includes (i) a chlorine doped silica based core having a core alpha (Core.sub.α)≥4, a radius r.sub.1, and a maximum refractive index delta Δ.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 Δ.sub.2, a radius r.sub.2, and a minimum refractive index delta Δ.sub.2min such that Δ.sub.2min<Δ.sub.1max, b) a second inner cladding adjacent to and in contact with the first inner cladding having a refractive index Δ.sub.3, a radius r.sub.3, and a minimum refractive index delta Δ.sub.3min such that Δ.sub.3min<Δ.sub.2, and c) an outer cladding region surrounding the second inner cladding region and having a refractive index Δ.sub.5, a radius r.sub.max, and a minimum refractive index delta Δ.sub.3min such that Δ.sub.3min<Δ.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 nm≤zero dispersion wavelength≤1324 nm, and a macrobending loss at 1550 nm for a 20 mm mandrel of less than 0.75 dB/turn.

An optical fiber with low attenuation and methods of making same are disclosed. The optical fiber has a core, an inner cladding surround the core, and an outer cladding surrounding the inner cladding. The outer cladding is chlorine-doped such that the relative refractive index varies as a function of radius. The radially varying relative refractive index profile of the outer cladding reduces excess stress in the core and inner cladding, which helps lower fiber attenuation while also reducing macrobend and microbend loss. A process of fabricating the optical fiber includes doping an overclad soot layer of a soot preform with chlorine and then removing a portion of the chlorine dopant from an outermost region of the overclad soot layer. The soot preform with the modified chlorine dopant profile is then sintered to form a glass preform, which can then be used for drawing the optical fiber.

An optical fiber according to an embodiment includes: a core; an inner cladding surrounding the core and having a refractive index smaller than a refractive index of the core; an outer cladding surrounding the inner cladding and having a smaller refractive index than the refractive index of the core and having a refractive index greater than the refractive index of the inner cladding, in which a ratio of a caustic radius to a MAC-value (caustic radius/MAC-value) at a bending radius of 10 mm at a wavelength of 1625 nm is 2.70 μm or more.

In some embodiments, a data center optical communications system includes: a transmitter comprising a light source, wherein the light source is configured to provide light; an optical fiber operably connected to said transmitter and configured to receive light from the light source, wherein the optical fiber has a length L of 50 km or greater; a receiver configured to receive light from the optical fiber, wherein the receiver includes a detector for detecting the light, wherein the system has a power consumption of 15 W or less