Disclosed herein is a glass composition that includes, based on the total weight of the composition, 52 wt % to 58 wt % of SiO.sub.2, 12 wt % to 16 wt. of Al.sub.2O.sub.3, 16 wt % to 26 wt % of B.sub.2O.sub.3, greater than 0 wt % and not greater than 2 wt % of MgO, 1 wt % to 6 wt % of CaO, greater than 1 wt % and lower than 5 wt % of TiO.sub.2, greater than 0 wt % and not greater than 0.6 wt % of Na.sub.2O, 0 wt % to 0.5 wt % of K.sub.2O, 0 wt % to 1 wt % of F.sub.2, 1 wt % to 5 wt % of ZnO, greater than 0 wt % and not greater than 1 wt % of Fe.sub.2O.sub.3; and 0.1 wt % to 0.6 wt % of SO.sub.3. Also disclosed herein is a glass fiber including the glass composition.

The present invention discloses a glass with high refractive index for fiber optic imaging elements with medium-expansion and fabrication method therefor, the glass comprising the following components in percentage by weight: SiO.sub.2 5-9%, Al.sub.2O.sub.3 0-1%, B.sub.2O.sub.3 23-28%, CaO 0-3%, BaO 6-12%, La.sub.2O.sub.3 30-34%, Nb.sub.2O.sub.5 4-8%, Ta.sub.2O.sub.5 0-1%, Y.sub.2O.sub.3 0-1%, ZnO 4-9%, TiO.sub.2 4-8%, ZrO.sub.2 4-6%, SnO.sub.2 0-1%. The present invention further provides a fabrication method for the glass with a high refractive index, comprising: putting raw materials quartz sand, aluminum hydroxide, boric acid or boric anhydride, calcium carbonate, barium carbonate or barium nitrate, lanthanum oxide, niobium oxide, tantalum oxide, yttrium oxide, zinc oxide, titanium dioxide, zirconium oxide and stannic oxide, etc. into a platinum crucible according to the requirement of dosing, melting at a high temperature, cooling and fining, leaking and casting to form a glass rod, and then annealing, cooling and chilling the molded glass rod.

Bromine doping of silica glass is demonstrated. Bromine doping can be achieved with SiBr.sub.4 as a precursor. Bromine doping can occur during heating, consolidation or sintering of a porous silica glass body. Doping concentrations of bromine increase with increasing pressure of the doping precursor and can be modeled with a power law equation in which doping concentration is proportional to the square root of the pressure of the doping precursor. Bromine is an updopant in silica and the relative refractive index of silica increases approximately linearly with doping concentration. Bromine can be used as a dopant for optical fibers and can be incorporated in the core and/or cladding regions. Core doping concentrations of bromine are sufficient to permit use of undoped silica as an inner cladding material in fibers having a trench in the refractive index profile. Co-doping of silica glass with bromine and chlorine is also demonstrated.

A rare earth-doped double-clad optical fiber includes a rare earth ion-doped fiber core, an inner cladding layer, and an outer cladding layer. A cross section of the inner cladding layer is a non-circular plane including at least two arcuate notches. According to the provided optical fiber, optical processing can be performed on a preform without changing a preform preparation process and a drawing process. The inner cladding is designed to have a non-circular planar structure having a cross section with at least two arcuate notches. While maintaining the same light absorption efficiency of pump light within the cladding layer, a preform polishing process is simplified, a risk of cracking the preform during polishing of multiple surfaces and a risk of contamination of the preform caused by impurities are reduced, wire drawing control precision is better, and comprehensive performance of the optical fiber is improved.

Multimode optical fibers are disclosed herein. In some embodiment disclosed herein, a multimode optical fiber having a bandwidth of greater than 2 GHz.Math.km includes: a glass matrix having a front endface, a back endface, a length (L), a refractive index n.sub.20 and a central axis (AC); and a plurality of cores arranged within the glass matrix, wherein the plurality of cores run generally parallel to the central axis between the front and back endfaces and having respective refractive indices n.sub.50, wherein n.sub.50>n.sub.20, wherein the glass matrix serves as a common cladding for the plurality of cores so that each core and the common cladding define a waveguide, wherein each core is a single mode at an operating wavelength; and wherein any two cores have an center-to-center spacing s of 3 m to 20 m and a coupling coefficient of greater than 10 m.sup.1 but less than 200 m.sup.1.

A Photonic Crystal Fiber (PCF) a method of its production and a supercontinuum light source comprising such PCF. The PCF has a longitudinal axis and includes a core extending along the length of said longitudinal axis and a cladding region surrounding the core. At least the cladding region includes a plurality of microstructures in the form of inclusions extending along the longitudinal axis of the PCF in at least a microstructured length section. In at least a degradation resistant length section of the microstructured length section the PCF includes hydrogen and/or deuterium. In at least the degradation resistant length section the PCF further includes a main coating surrounding the cladding region, which main coating is hermetic for the hydrogen and/or deuterium at a temperature below T.sub.h, wherein T.sub.h is at least about 50 C., preferably 50 C.<T.sub.h<250 C.

An optical fiber including a glass core, and a polymer cladding formed around the glass core, the polymer cladding containing a mixture of a polymerizable composition and a silane coupling agent, and a fluorine-based ultraviolet curable resin. The mixture contains 5 to 95 parts by weight of the silane coupling agent based on 100 parts by weight of the total weight of the mixture. The fluorine-based ultraviolet curable resin alone has a refractive index in a range of 1.350 to 1.420 after ultraviolet curing. A component originated from the silane coupling agent is concentrated within a range of 20 m or less in the polymer cladding from an interface between the glass core and the polymer cladding.

An optical fiber having at least two polymer coatings, the optical fiber comprising: an optical fiber comprising a glass optical core and a glass cladding; a first polymer coating comprising a silicone polymer covering the optical fiber; and a second polymer coating covering the first polymer coating is provided.

An optical material including: a silica host; and a Praseodymium dopant; wherein the Praseodymium atoms are configured to form nanoclusters in the silica host. In addition, the optical material may include an Ytterbium co-dopant. The nanoclusters include Ge, Te, Ta, Lu and/or F, Cl to minimize multi-phonon quenching. Moreover, the nanoclusters may be encapsulated in a low phonon energy shell to minimize energy transfer to the host matrix.

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.