An optical fibre for use in fibre lasers has the lasing additive, eg Er³⁺, concentrated in centre (13) of the core (14). Preferably the core (14) has an inner region (13) which contains the additive and an outer region (12) which is dopant free. The concentration of the dopant reduces the pump threshold for a laser and improves the gain performance for a given pump power. The fibre is conveniently made by MCVD. The use of Al₂O₃ in the inner zone appears to reduce loss of dopant during tube collapse.

Optical fibre with fluorescent additive

A grey glass composition employing as its colorant portion at least iron (Fe2O3/FeO) and erbium oxide (e.g., Er2O3), and also preferably selenium and cobalt. An exemplary colorant portion for use in a glass composition (with a soda lime silica or other suitable base glass) includes, by weight percentage : total iron (expressed as Fe2O3) :0.1 to 0.6%; erbium oxide (e.g., Er2O3) : 0.3 to 1.5%; selenium (Se) : 0.0002 to 0.0010%; cobalt oxide (e.g., Co3O4) : 0.0005 to 0.0018%; titanium oxide (e.g., TiO2) : 0.0 to 1.0%; boron oxide (e.g., B2O3) : 0.0 to 2.0%. The resulting glass may exhibit high visible transmittance (Lta), while at the same time low UV and IR transmittance.

Grey glass composition including erbium

A contact lens having a unitary molded central portion containing a light sensitive material which varies in light transmission with variations in the intensity of ambient light. One embodiment has an assembly of components secured to the lens by molding. The assembly also contains a light sensitive material.

Contact lens containing light sensitive material

A system for producing an optical gain. The system includes an optical fiber having a core and a cladding, the core being doped with Pr 3+ ; and a source producing light to energize the Pr 3+ to the 1 G 4 state and produce an optical gain by a 1 G 4 - 3 H 5 transition at a wavelength in the range of 1.25 to 1.34 microns. The system also includes a method of making and a method of using the same.

Praseodymium laser system

A high LTa, low UV and IR transmittance grey glass employing as its colorant portion iron (Fe2O3/FeO), erbium (Er2O3) and, optionally, titanium (TiO2). Enhanced effects are achieved by forming separate prebatch mixes, one of which includes rouge, metallic Si (optional), SiO and sand, the other including the remainder of ingredients, which after separate formation are then admixed to form the final, overall batch.

Grey glass composition and method of making same

A reversible light-sensitive glass comprising 100 parts of a base glass composition consisting, in weight percent, of 48 to 62% SiO2, 15 to 22% B2 O3, 0 to 7% Al2 O3, 0 to 10% ZrO2, 6<Al2 O3 + ZrO2 <12%, 6 to 16% R2 O where R represents Li, Na or K, 05 to 7% BaO, BaO/R2 O 0035 to 065, 0 to 2% TiO2, and 0002 to 003% CuO, and as light-sensitive components, 015 to 10 part of Ag and more than the chemical Ag equivalent of halogens selected from the group consisting of Cl, Br and I

Reversible light sensitive glass

A single mode laser glass fiber showing excellent laser oscillation characteristics even at a short fiber length can be efficiently obtained using a phosphate laser glass with excellent laser characteristics.

Single mode phosphate laser glass fiber

A Faraday rotation single-mode fiber having a high Verdet constant is disclosed, the core and the cladding of the fiber being made of a glass having the following composition: 26 to 38 mol % SiO2, 18 to 34 mol % B2 O3, 17 to 26 mol % Al2 O3, 18 to 32 mol % Tb2 O3, 0 to 5 mol % ZrO2, 0 to 5 mol % Ce2 O3, 0 to 5 mol % Pr2 O3, 0 to 5 mol % Dy2 O3 and 0 to 5 mol % Ho2 O3, provided that the total amount of the above ingredients is not less than 97 mol % and the total amount of Ce2 O3, Pr2 O3, Dy2 O3 and Ho2 O3 is 0 to 5 mol %.

Faraday rotation single-mode optical fiber

APHOTOCHROMIC GLASS COMPRISING A BASE GLASS CONSISTING OF CERTAIN PROPORTIONS OF SIO2AL2O3, B2O3, K2O3 AND BAO, IN WHICH THE RATIO OF BAO/K2O IS 0.05-0.40, AND POPHOTOSENSTIVE INGREDIENTS CONSISTING OF 0.15-0.7 PARTS OF AG AND ONE OR MORE OF CL, BR AND I IN AN AMOUNT CORRESPONDING TO MORE THAN THE CHEMICAL EQUIVALENT OF AG FOR EVERY 100 PARTS OF THE BASE GLASS. A PROCESS FOR PRODUCING THE GLASS BY PRELIMINARILY HEATING THE GLASS AT A TEMPERATURE OF 300-450*C. FOR NOT LESS THAN 30 MINUTES AND THEN FURTHER HEAT-TREATING THE GLASS AT A TEMPERATURE BETWEEN THE STRAIN TEMPERATURE AND THE SOFTENING TEMPERATURE OF THE GLASS, THEREBY IMPROVING THE PHOTOCHROMIC PROPERTIES.

Photochromic glass and process for producing the same

PURPOSE:To produce long-sized phosphate layer glass multiple mode fiber which has various characteristics and is excellent in optical quality by using phosphate laser glass contg. Nd2O3 as a core and covering it with phosphate-base glass having thermal properties close to core glass. CONSTITUTION:The circumference of phosphate laser glass having composition consisting of by mol% indication 45-70% P2O5, 4-20% Al2O3, 0-20% SiO2, 0-35% one and two or more kinds of R''O such as MgO, CaO, SrO, BaO, ZnO and PbO, 0-30% one and two or more kinds of R'2O such as Li2O, Na2O and K2O, 0.1-12% Nd2O3, 0-15% Y2O3 and the other oxide and 0-1% CeO as a core material is covered by phosphate-base glass consisting of same-quality P2O5, Al2O3 and SiO2 as the core material, 0-13% B2O3, 0-35% R''O, 0-30% R'2O, 0-5% Y2O3 and the other oxide and 0-1% CeO2. Phosphate laser glass multiple mode fiber excellent in laser characteristics, optical characteristics, chemical durability and mechanical properties is obtained.

Toshiharu Yamashita

Papers

Reversible light sensitive glass

Single mode phosphate laser glass fiber

Faraday rotation single-mode optical fiber

Photochromic glass and process for producing the same

Phosphate laser glass multiple mode fiber