A dispersion shifted optical fiber where a radius r.sub.0 of a first center segment is 0.5 μm to 2.8 μm, and a relative refractive index difference Δ.sub.0 is 0.4% or more and 0.9% or less. A radius r.sub.1 of a first segment is 1.8 μm or more and 4.5 μm or less. A radius r.sub.2 of a second segment is 4.0 μm or more and 8.0 μm or less, and a relative refractive index difference Δ.sub.2 is 0.00% or more and 0.07% or less. A radius r.sub.3 of a third segment is 4.5 μm or more and 8.5 μm or less, and a relative refractive index difference Δ.sub.3 is 0.285% or more and 0.5% or less. A radius r.sub.4 of a fourth segment is 8.0 μm or more and 16.0 μm or less, and a relative refractive index difference Δ.sub.4 is 0.005% or more and 0.04% or less.

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, an inner cladding, a first trench region, an intermediate cladding, a second trench region, and an outer cladding. The core has a first radius. The inner cladding is defined by the first radius and a second radius of the optical fibre. The first trench region is defined by the second radius and a third radius. The first trench region. The intermediate cladding is defined by the third radius and a fourth radius. The second trench region is defined by the fourth radius and a fifth radius. The outer cladding is defined by the fifth radius and a sixth radius.

The optical fibers disclosed have single mode and few mode optical transmission for VCSEL-based optical fiber transmission systems. The optical fibers have a cable cutoff wavelength λ.sub.C of equal to or below 1260 nm thereby defining single mode operation at wavelengths greater than 1260 nm and few-mode operation at wavelengths in a wavelength range from 800 nm and 1100 nm. The mode-field diameter is in the range from 8.0 microns to 10.1 microns at 1310 nm. The optical fibers have an overfilled bandwidth OFL BW of at least 1 GHz.Math.km at at least one wavelength in the wavelength range. The optical fibers have a single-step or two-step core and can have a trench refractive index profile. VCSEL based optical transmission systems and methods are disclosed that utilize both single core and multicore versions of the optical fiber.

The present disclosure provides an optical fibre. The optical fibre includes a core, an inner cladding, a first trench region, an intermediate cladding, a second trench region, and an outer cladding. The core has a first radius. The inner cladding is defined by the first radius and a second radius of the optical fibre. The first trench region is defined by the second radius and a third radius. The first trench region. The intermediate cladding is defined by the third radius and a fourth radius. The second trench region is defined by the fourth radius and a fifth radius. The outer cladding is defined by the fifth radius and a sixth radius.

An example of an optical fiber includes an attenuating cladding disposed around a first waveguide (e.g., a core) and a waveguide (e.g., a waveguide cladding) disposed around the attenuating cladding. An attenuating cladding may be a doped layer that may be doped with, for example, a dopant comprising metal. A first waveguide and a second waveguide may each transmit light for a distinct sample characterization technique. An example of an optical fiber includes a core, a first intermediate cladding disposed around the core, an attenuating cladding disposed around the first intermediate cladding, an attenuating cladding disposed around the first intermediate cladding, a second intermediate cladding disposed around the attenuating cladding, a waveguide cladding disposed around the second intermediate cladding, and outer cladding disposed around the waveguide cladding, and an outer coating around the outer cladding. An optical fiber may be formed using a rod-in-tube process.

A multi-clad optical fiber is provided. The fiber includes, concentrically and radially outwards from the center of the optical fiber, a core doped with at least one rare-earth dopant material, a pedestal cladding structure, an inner cladding and an outer cladding. The pedestal cladding structure includes a pedestal layer having a refractive index smaller than a refractive index of the core, and a raised index layer having a refractive index larger than the refractive index of the pedestal layer. The raised index layer has a thickness and a refractive index which preserve the confinement of the core mode in the core and minimize the overlap of one or more pedestal modes with the core.

A multi-clad optical fiber is provided. The fiber includes, concentrically and radially outwards from the center of the optical fiber, a core doped with at least one rare-earth dopant material, a pedestal cladding structure, an inner cladding and an outer cladding. The pedestal cladding structure includes a pedestal layer having a refractive index smaller than a refractive index of the core, and a raised index layer having a refractive index larger than the refractive index of the pedestal layer. The raised index layer has a thickness and a refractive index which preserve the confinement of the core mode in the core and minimize the overlap of one or more pedestal modes with the core.

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 optical fibers disclosed have single mode and few mode optical transmission for VCSEL-based optical fiber transmission systems. The optical fibers have a cable cutoff wavelength .sub.d C of equal to or below 1260 nm thereby defining single mode operation at wavelengths greater than 1260 nm and few-mode operation at wavelengths in a wavelength range from 800 nm and 1100 nm. The mode-field diameter is in the range from 8.0 microns to 10.1 microns at 1310 nm. The optical fibers have an overfilled bandwidth OFL BW of at least 1GHz.Math.km at at least one wavelength in the wavelength range. The optical fibers have a single-step or two-step core and can have a trench refractive index profile. VCSEL based optical transmission systems and methods are disclosed that utilize both single core and multicore versions of the optical fiber.