An optical fiber for efficient coupling of optical signals to photonic devices. The optical fiber includes a Cl doped tapered core region with a changing outer diameter and changing maximum core refractive index to provide improved coupling at wavelength of interest to photonic devices. The photonic devices may be, for example, silicon photonic devices with an operating wavelength at or near 1310 nm, or at or near 1550 nm.

Provided is an image guide fiber that improves image quality while preventing a manufacturing problem. The image guide fiber according to the present disclosure has a numerical aperture NA in the range of 0.70 to 0.90. A linear thermal expansion coefficient difference , which is a value obtained by subtracting a linear thermal expansion coefficient .sub.2 at from 100 to 300 C. of clad glass, from a linear thermal expansion coefficient .sub.1 at from 100 to 300 C. of core glass, is in the range of 310.sup.7/ C. to 1510.sup.7/ C. A glass-transition temperature Tg.sub.1 of the core glass is higher than a glass-transition temperature Tg.sub.2 of the clad glass. A core occupancy area ratio is 25% or more. A pixel density is 0.1 pixel/m.sup.2 or more.

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.

The invention relates to a method and device for fiber optic temperature measurement. The invention also relates to a multimode quartz glass fiber with nanocomposite (NK) containing a polymer and quantum dots (QDs) and its manufacture. These are based on temperature-dependent emission of quantum dots on the surface of optical fibers.

An optical fiber includes a core portion made of silica-based glass; and a cladding portion made of silica-based glass having lower maximum refractive index than the core portion, the cladding portion surrounding an outer periphery of the core portion. The core portion is doped with an alkali metal element and chlorine. An average concentration of chlorine is higher than 800 atomic ppm on a cross-section perpendicular to a longitudinal direction of the core portion. A region doped with the alkali metal element is larger than a region doped with chlorine at 800 atomic ppm or higher.

The present invention relates to a glass substrate for a high-frequency device, which includes SiO.sub.2 as a main component, the glass substrate having a total content of alkali metal oxides in the range of 0.001-5% in terms of mole percent on the basis of oxides, the alkali metal oxides having a molar ratio represented by Na.sub.2O/(Na.sub.2O+K.sub.2O) in the range of 0.01-0.99, and the glass substrate having a total content of Al.sub.2O.sub.3 and B.sub.2O.sub.3 in the range of 1-40% in terms of mole percent on the basis of oxides and having a molar ratio represented by Al.sub.2O.sub.3/(Al.sub.2O.sub.3+B.sub.2O.sub.3) in the range of 0-0.45, in which at least one main surface of the glass substrate has a surface roughness of 1.5 nm or less in terms of arithmetic average roughness Ra, and the glass substrate has a dielectric dissipation factor at 35 GHz of 0.007 or less.

A radiation-resistant laser optical fiber preform core rod at least includes one type of activated ion (Yb.sup.3+, Er.sup.3+) and one or more types of co-doped ion (Al.sup.3+, P.sup.5+, Ge.sup.4+, Ce.sup.3+, F.sup.?), and OD group of 16-118 ppm. Irradiation resistance of core rod glass can be effectively improved by sequentially performing pre-treatments, i.e. deuterium loading, pre-irradiation and thermal annealing on a preform core rod. Electron paramagnetic resonance test shows that, under the same radiation condition, the radiation induced color center concentration in a preform core rod treated by the method above is lower than in an untreated core rod by one or more orders of magnitude. The obtained core rod can be used for preparing a radiation-resistant rare earth-doped silica fiber, and has the advantages of high laser slope efficiency, low background loss, being able to be used stably in a vacuum environment for a long time, for example.

The glasses of the present disclosure are highly transparent and have very good resistance to solarization. The resistance to solarization arises from the production method. The concentrations of reduced polyvalent ion species are reduced by targeted use of bubbling with an oxidizing gas. Methods for producing glasses and to the uses thereof, particularly as core glasses in optical waveguides, are also provided.

In an FOP 1, a glass body 8 is configured by including antimicrobial glass portions 10 made of antimicrobial glass containing Ag.sub.2O. Here, the glass containing silver does not have chemical durability, so that it has properties to easily emit Ag ions due to moisture. Ag ions have an excellent antimicrobial effect. Therefore, by configuring the glass body 8 to include the antimicrobial glass portions 10 containing Ag.sub.2O, the glass body 8 can obtain a sterilization effect due to the action of Ag ions. Therefore, the FOP 1 can be provided with antimicrobial activities.

The single-mode optical fibers have a core region that includes an inner core region having a delta value .sub.1 and a radius r.sub.1 immediately surrounded by an outer core region of radius r.sub.2 and a delta value .sub.2<.sub.1, wherein .sub.1-.sub.2 is in the range from 0.3% to 2%. A cladding region of radius r.sub.3 immediately surrounds the core region. The inner and outer regions define an annular width r=r.sub.2r.sub.1. At least one of r.sub.1, r.sub.2, r and r.sub.3 changes with a period p in the longitudinal direction between first and second values each having a corresponding level distance d.sub.F. The change occurs over a transition distance d.sub.T such that d.sub.T/d.sub.F<0.1. The Brillouin frequency shift f changes by an amount [f] that is least 10 MHz over each period p, thereby allowing for Brillouin frequency-shift management in fiber-based sensor systems.