Nec Corporation

K-three Products Kabushiki Kaisha

Tadashi Kasamatsu

Yutaka Yano

Hitoshi Sekita

Toshimitsu Akiyama

A laser amplifier includes a gain medium of a glass fiber, a first exciting light source, a second exciting light source, and another first exciting light source. The gain medium of the glass fiber includes rare earth dopant in a host medium. Ions of the rare earth dopant has an energy level structure including a ground level and a pair of laser upper level and laser lower levels between which a stimulated transition is to be produced after production of a population inversion between the pair of laser upper and laser lower levels. The pair of laser upper and laser lower levels being higher than the ground level. The first exciting light source is coupled to the input side of the glass fiber for introducing first exciting light to the glass fiber to produce the population inversion. The second exciting light source is coupled to the input side of the glass fiber for introducing second exciting light source to the glass fiber to raise ions of the rare earth dopant from the ground level to the laser lower level. The second exciting light has a wavelength band different from a wavelength band of the first exciting light. The other first exciting light source is coupled to the output side of the glass fiber for introducing the first exciting light to the glass fiber. A two-way excitation is performed on the glass fiber.

OPTICAL FIBER AMPLIFIER THAT CAN ATTAIN SUFFICIENT GAIN SHIFT EFFECT, SMALL NOISE PROPERTY AND HIGH OPERATION EFFICIENCY AT THE SAME TIME EVEN IN TWO-WAVELENGTH EXCITATION TM DOPANT OPTICAL FIBER AMPLIFIER, AND OPTICAL AMPLIFIER HAVING THE SAME

Two semiconductor laser light sources for outputting light of two properly selected wavelengths are employed as excitation light sources. That is, as excitation light sources, there are used a first semiconductor laser excitation light source for exciting ion from a base level to a laser low level or an energy level higher than the laser low level and a second semiconductor laser excitation light source having a wavelength different from that of the first excitation light source for exciting ion from a laser low level to a laser high level. For example, an amplification fiber uses a fluoro zircon ate glass as a base material. Two multiple wavelength couplers are disposed at the input side of the amplification fiber. The multiple wavelength couplers are connected to the first excitation light source and the second excitation light source, respectively. An isolator is disposed at a signal input port at the further input side of the multiple wavelength couplers, and an another isolator is disposed at an output port of the amplification fiber.

Laser amplifier, method and apparatus for laser amplification, and laser oscillator

A laser crystal is formed on a substrate in a solid-state laser device. The laser crystal oscillates laser beam from a second end face when an excitation beam is projected to a first end face. An excitation beam emission element emitting the excitation beam is provided for the solid-state laser device. A waveguide path is formed on the substrate. The excitation beam is transmitted through the waveguide path. The waveguide path has a first end portion on which the excitation beam emitted by the excitation beam emission element impinges and a second end portion which opposes the first end face of the laser crystal. The excitation beam is emitted from the second end portion.

Solid-state laser device and solid-state laser amplifier provided therewith

A laser amplifier and/or oscillator comprise a gain medium including rare earth dopant in an host medium. Ions of the rate earth dopant has an energy level structure including a ground level and a pair of laser upper level and laser lower levels between which a stimulated transition is to be produced after production of a population inversion between the pair of laser upper and laser lower levels. A first exciting light source is coupled to the gain medium for introducing first exciting light to said gain medium to produce said population inversion. A second exciting light source is coupled to the gain medium for introducing second exciting light to the gain medium to raise the rare earth dopant ions from the ground level to the laser lower level.

Laser oscillator and laser amplifier

An optical waveguide including a single-mode waveguide in which an induced radiation ray generated by exciting the ion propagates in a single-mode in both of a thickness direction and a width direction in the single-mode waveguide; and multi-mode waveguides disposed along both of side surfaces of the single-mode waveguide in which the ray propagates in a single-mode in a thickness direction of the multi-mode waveguide and propagates in a multi-mode in a width direction. In accordance with the present invention, the exciting ray is easily absorbed because the ray propagates to cross the single-mode waveguide without a skew-mode propagation, and the laser and the photo-amplifier which can obtain a higher output in the single-mode is provided.

Optical device

In a quasi-three-level solid-state laser that is excited by a semiconductor laser, a temperature-controlling apparatus is used to operate the crystal temperature that enables optimum laser operation in terms of both efficiency and output, based on the effect that cooling the crystal has on reducing the efficiency of absorption of power from the semiconductor excitation laser and the effect that cooling the crystal has on lowering the oscillation threshold value.

Solid-state laser device

Disclosed is an improved method of producing corrugated cardboards, in which water suspension of raw starch is used as an adhesive. The raw starch is, after application thereof, heated to form gell or paste with dry steam prepared by reheating low-pressure steam with high-pressure steam. Also, disclosed is an apparatus for practicing the improved method.

Growing community of inventors

Tokyo, Japan

Tadashi Kasamatsu