Central Glass Company, Limited

Natsuya Nishimura

Yoshinori Kubota

Kiyotaka Miura

Hiromi Kawamoto

Akira Sakanoue

Takuya Teshima

Hiroyuki Inoue

Takayoshi Morinaka

Yasushi Kita

Keita Nakahara

Seiji Fujiwara

Yuta Ikeda

To provide a manufacturing method with which lithium difluorophosphate powder can be recovered from a lithium difluorophosphate solution. A method for manufacturing lithium difluorophosphate powder is used which includes the steps of precipitating solid lithium difluorophosphate by adding a poor solvent to a solution in which lithium difluorophosphate is dissolved in a main solvent, and obtaining lithium difluorophosphate powder by solid-liquid separation of the solid lithium difluorophosphate from the liquid containing the main solvent and the poor solvent, wherein the relational expression between the octanol/water partition coefficient Pof the main solvent and the octanol/water partition coefficient Pof the poor solvent is defined by the following formula (1).&#x2265;&#x2212;4/3&#xd7;+1.2&#x2003;&#x2003;(1):

Manufacturing method for lithium difluorophosphate powder, and lithium difluorophosphate

A glass includes (a) a matrix containing a compound of at least one nonmetallic element; and (b) a particle selectively formed in the matrix. This particle is made of the at least one nonmetallic element. A process for producing such glass includes (a) providing a blank glass containing a compound of at least one nonmetallic element; (b) condensing a pulsed laser beam to a focal point in the blank glass such that a particle is selectively formed in the blank glass at a position corresponding to the focal point, the particle being made of the at least one nonmetallic element dissociated from the compound; and (c) moving the focal point in the blank glass to produce a pattern of the particle. The glass is suitable for optical functional elements.

Glass suitable for optical functional elements and process for producing same

Pulsed light is irradiated to an amorphous base material, to produce therein one or more single crystals or polycrystals having nonlinear characteristic advantageous for light communication and laser technique. An external field such as electric field or magnetic field may be applied to the amorphous material, or a seed crystal or crystalline substrate may be used to promote crystallization from a contact interface between the amorphous material and the seed crystal or crystalline substrate.

Process for producing amorphous material containing single crystal or polycrystal and material produced

The invention relates to a 1.4-1.52 &mgr;m-band optical amplifier. This optical amplifier includes (a) a first pumping source for a first pumping light in a wavelength range defined as being not less than 0.65 &mgr;m and being less than 0.77 &mgr;m; (b) a second pumping source for a second pumping light in a wavelength range of from 1.0 to 1.2 &mgr;m; (c) an optical multiplexer for combining said first and second pumping lights with a signal light, to produce a combined light; and (d) a light amplifying optical waveguide for amplifying said signal light by receiving said combined light, said optical waveguide comprising a core doped with Tm. The optical amplifier is highly efficient.

1.4-1.52 &mgr;m-band optical amplifier

The invention relates to an optical waveguide having a core made of one member selected from halide glasses, chalcogenide glasses and oxyhalide glasses. This one member is doped with both of erbium and cerium. The invention further relates to a 1.5 &mgr;m-band optical amplifier having the optical waveguide for amplifying the light. Due to the doping of both erbium and cerium, it becomes possible to provide a highly efficient optical amplifier having low noise and wide band. With this, it becomes possible to construct an optical communication network having high credibility, high capacity and high speed.

Optical waveguide and 1.5 &mgr;m-band optical amplifier using same

An upconversion laser material includes a micro-sphere which is doped with an ion of a rare earth element and made of one selected from the group consisting of crystals and glasses. Thus, the micro-sphere achieves the light confinement therein and serves as a resonator. Therefore, the Q-value of the resonator becomes large. With this, it is possible to obtain the upconversion laser oscillation at room temperature.

Upconversion laser material

An optical fiber preform includes a core made from a fluoride glass which is doped with a rare earth, and a cladding surrounding the core. The cladding is made from one of an oxide glass and a fluoroxide glass. The core has a characteristic of amplification at 1.3 .mu.m-band. The cladding does not have absorption at 1.3 .mu.m-band. The preform is useful as a material for a fiber optical amplifier in optical communication systems.

1.3 micrometer-band amplifying optical fiber preform

A method of forming a fiber glass preform includes the steps of: (a) pouring a cladding glass into a mold; (b) pouring a core glass on a flat horizontal upper surface of the cladding glass so as to form a united glass body having the core glass and the cladding glass under a condition that viscosity of the cladding glass and viscosity of the core glass are adjusted to certain predetermined values respectively so that the core glass is separated from and placed on the cladding glass; (c) cooling the united glass body to solidify the same so that the cladding glass is deformed by contraction thereof so as to produce a depression at a top middle portion thereof and that the core glass is deformed so as to form a projected portion thereof to fill the depression therewith; (d) separating the united glass body into an upper portion and a lower portion comprising the projected portion of the core glass; and (e) extruding the lower portion of the united glass body so as to form the fiber glass preform.

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Yamaguchi, Japan

Natsuya Nishimura