Methods for classifying a core cane of an multimode optical fiber are disclosed. In embodiments, the method includes determining a relative refractive index profile Δ(r) of the core cane; fitting the relative refractive index profile Δ(r) to an alpha profile Δ.sub.fit(r) defined by:

[00001]${\Delta }_{\mathrm{fit}}\left(r\right)={\Delta }_{o,\mathrm{fit}}\left(1-{\left(\frac{r}{a_{\mathrm{fit}}}\right)}^{{\alpha }_{\mathrm{fit}}}\right)$

where Δ.sub.o,fit is a relative refractive index at a longitudinal centerline of the core cane, α.sub.fit is a core shape parameter, and a.sub.fit is an outer radius of the core cane; generating a non-alpha residual profile Δ.sub.diff(r)=Δ(r)−Δ.sub.fit(r) for the core cane; computing one or more metrics from Δ.sub.diff(r), and using the one or metrics in a classification of the core cane, the classification comprising a prediction of whether a bandwidth at a pre-determined wavelength of an optical fiber drawn from a preform comprising the core cane exceeds a pre-determined bandwidth at the pre-determined wavelength.

Described herein are systems, methods, and articles of manufacture for a spatially nonuniform scattering profile along its length, whose backscattering signal can be used for sensing even after fiber attenuation increases due to the conditions in the sensing environment. In one embodiment, the fiber has been pre-exposed to the conditions that produce attenuation, and the spatially nonuniform profile compensates for this. Subsequent exposure then results in very little or at least acceptable levels of additional attenuation. An exemplary fiber comprises a fiber length and an optical back scatter along the fiber length greater than a Rayleigh back scattering over the fiber length, wherein the optical back scatter does not decrease along the fiber length by more than 3 dB after exposure to a hydrogen-rich first environment having a given pressure and temperature. An exemplary method comprises drawing a fiber, applying a UV coating, post-processing the fiber using an interferogram, measuring optical back scatter enhancement dependence based on a UV dosage, incrementally increasing the reflectivity, exposing the fiber to a hydrogen-rich first environment.

Described herein are systems, methods, and articles of manufacture for a spatially nonuniform scattering profile along its length, whose backscattering signal can be used for sensing even after fiber attenuation increases due to the conditions in the sensing environment. In one embodiment, the fiber has been pre-exposed to the conditions that produce attenuation, and the spatially nonuniform profile compensates for this. Subsequent exposure then results in very little or at least acceptable levels of additional attenuation. An exemplary fiber comprises a fiber length and an optical back scatter along the fiber length greater than a Rayleigh back scattering over the fiber length, wherein the optical back scatter does not decrease along the fiber length by more than 3 dB after exposure to a hydrogen-rich first environment having a given pressure and temperature. An exemplary method comprises drawing a fiber, applying a UV coating, post-processing the fiber using an interferogram, measuring optical back scatter enhancement dependence based on a UV dosage, incrementally increasing the reflectivity, exposing the fiber to a hydrogen-rich first environment.

Provided is a system for and a method of processing an optical fiber, such as tapering an optical fiber. The method includes receiving fiber parameters defining characteristics of an optical fiber, modeling an idealized fiber based on the fiber parameters to establish modeled data, and establishing processing parameters. A processing operation is performed on the optical fiber according to the processing parameters to produce a resultant fiber. Aspects of the resultant fiber are measured to establish measured data. The measured data and the modeled data are normalized to a common axis and a difference between the two is determined. The processing parameters are adjusted based on the differences.

Disclosed in the present invention is a beam coherence eliminating element. The optical medium material of the element comprises microcrystalline glass, wherein microcrystalline particles therein have a size of 0.1-1000 nm and are distributed randomly. As the crystals in the microcrystalline glass can change the phase of light beams, the microcrystalline glass can change the phase of the light beams randomly, thereby eliminating the coherence of the beams. The crystal size of the microcrystalline glass is small, and thus does not affect the transmission efficiency of light beams. The element of the present invention has a simple structure and is convenient to use, and can be added in the process of beam transmission to easily eliminate beam coherence.

Disclosed in the present invention is a beam coherence eliminating element. The optical medium material of the element comprises microcrystalline glass, wherein microcrystalline particles therein have a size of 0.1-1000 nm and are distributed randomly. As the crystals in the microcrystalline glass can change the phase of light beams, the microcrystalline glass can change the phase of the light beams randomly, thereby eliminating the coherence of the beams. The crystal size of the microcrystalline glass is small, and thus does not affect the transmission efficiency of light beams. The element of the present invention has a simple structure and is convenient to use, and can be added in the process of beam transmission to easily eliminate beam coherence.

Apparatus, systems, and methods that provide coats on a glass optical fiber including of an inner layer and an outer layer. The method includes two steps. First, a conductive polymer coating is applied to the optical fiber as it is being produced. Second, a protective coating is applied to that conductive polymer coating. The conductive polymer coating is applied immediately after the fiber is drawn from preform to fiber.

Apparatus, systems, and methods that provide coats on a glass optical fiber including of an inner layer and an outer layer. The method includes two steps. First, a conductive polymer coating is applied to the optical fiber as it is being produced. Second, a protective coating is applied to that conductive polymer coating. The conductive polymer coating is applied immediately after the fiber is drawn from preform to fiber.

Method of producing glass components and preforms for use in the method. The preform includes a primary rod having a constant outside diameter and a square bottom and a sacrificial tip having a first end attached to the bottom of the primary rod, a second end opposite the first end, and a hollow interior region extending from the first end to the second end. The sacrificial tip is circular in cross section and the first end of the sacrificial tip has an outside diameter equal to the outside diameter of the primary rod. When the preform is heated in a furnace, the sacrificial tip melts and collapses into a drawing bulb which either draws the primary rod directly into the glass fiber or results in a tapered (i.e. tipped) preform for subsequent fiber draw. Material waste as well as the drip time is reduced and the cladding-to-core ratio, crucial for waveguide properties, is maintained for the whole preform compared to a square cut preform without the sacrificial tip.

Method of producing glass components and preforms for use in the method. The preform includes a primary rod having a constant outside diameter and a square bottom and a sacrificial tip having a first end attached to the bottom of the primary rod, a second end opposite the first end, and a hollow interior region extending from the first end to the second end. The sacrificial tip is circular in cross section and the first end of the sacrificial tip has an outside diameter equal to the outside diameter of the primary rod. When the preform is heated in a furnace, the sacrificial tip melts and collapses into a drawing bulb which either draws the primary rod directly into the glass fiber or results in a tapered (i.e. tipped) preform for subsequent fiber draw. Material waste as well as the drip time is reduced and the cladding-to-core ratio, crucial for waveguide properties, is maintained for the whole preform compared to a square cut preform without the sacrificial tip.