Fuji Photo Film Company, Limited

Fujifilm Corporation

Fuji Photo Co., Ltd.

Chiaki Goto

Yoji Okazaki

Hiroaki Hyuga

Akinori Harada

Masaru Noguchi

Kazuo Horikawa

Fusao Yamanaka

Takashi Adachi

Kenichi Saito

Jin Murayama

Hiroshi Sunagawa

Shinichi Shimotsu

Nobuharu Nozaki

Hideo Miura

Toshio Iijima

Kozi Kamiyama

Kenji Matumoto

Horikawa Kazuo

(Problem to be solved) To provide a laser beam synthesizing apparatus which is small in size and high in output power. (Means for solving the problem) A convergent angle transforming optical systemis disposed further upstream of the upstream-most position Pa in the positions where the optical axes of beam bundles La, Lb, Lc . . . which are radiated from a plurality of semiconductor lasersA,B,C . . . and converged in the fast axis view by a converging/dispersion lensintersect each other in the fast axis view, and the whole beam bundle made up of the beam bundles La, Lb, Lc . . . passed through the converging/dispersion lensis converged in the fast axis view by the convergent angle transforming optical systemso that the angle of convergence of the whole beam bundle is made smaller in the fast axis view, and introduced into the coreof an optical fiber

Apparatus for synthesizing laser beams

In a laser light multiplexing apparatus: a collimating optical system collimates light beams emitted from semiconductor lasers so that the slow axes of the light beams become coplanar, and optical axes of the light beams become parallel to each other; a light beam rearrangement optical system constituted by prisms respectively arranged in correspondence with the light beams rearranges the light beams in such a manner that directions of the fast axes of the light beams are changed at different locations along a direction in which the light beams propagate, and the fast axes of the light beams become coplanar; and a convergence optical system converges a bundle of the light beams rearranged by the light beam rearrangement optical system, in directions of the fast axes and the slow axes of the light beams, and makes the converged bundle of the light beams enter an optical fiber.

Laser multiplexing apparatus

A laser light source is equipped with a semiconductor light-emitting device, a first wavelength selector, and a second wavelength selector. The first and second wavelength selectors are used to select the wavelength of the light emitted from the light-emitting device, and constitute an external resonator. The semiconductor light-emitting device is provided with a stripe, which is formed oblique to the cleaved end facets of the light-emitting device that do not constitute the external resonator. The end facets of the semiconductor light-emitting device are provided with coatings, which become antireflective coatings with respect to the selected wavelength.

Laser light source

An optical system for scanning which facilitates, at a time of assembling a plurality of optical elements forming an optical system for scanning, adjustment of positional relationships between the optical elements so that an appropriate laser beam is irradiated. In a light source unit, an SHG module and a collimator lens are assembled on a first base which is formed of covar, and this first base is mounted via an adjustment spacer to a second base at one end thereof in a longitudinal direction. An AOM is mounted to the other end of the second base. In this way, in this light source unit, adjustment of the positional relationships between the optical elements at a time of assembly is facilitated. In addition, regardless of whether an impact is applied at the time of assembly or whether a temperature or the like changes after assembly, an appropriately modulated laser beam can be irradiated.

Optical system for scanning

A solid state laser includes a solid state laser crystal, a pumping source for pumping the laser crystal, a resonator, an enclosed casing which is filled with gas and in which the resonator is contained, and a temperature controller which keeps the resonator at a predetermined temperature. The ratio of the optical length of the gas layer in the resonator to the oscillation wavelength of the solid state laser is set to be not larger than 13600.

Solid state laser

In a wavelength conversion laser, a laser crystal is pumped by light and the wavelength of a solid state laser beam emitted from the laser crystal is converted by a nonlinear optical crystal having a periodic domain reversal structure and disposed in a resonator. A +c-face and a -c-face of the nonlinear optical crystal are electrically connected to each other at least at portions of the faces close to the optical path of the solid state laser beam.

Wavelength conversion laser

A polarization control element for controlling the direction of polarization and the longitudinal mode of a laser is formed by cutting a birefringent crystal so that its light incident face and light emanating face are at an angle to the optical axis of the crystal and adjusting the thickness and the reflectivities of the faces of the crystal so that the crystal can function as a Fabry-Perot etalon. The thickness of the birefringent crystal is set so that the wavelengths selected by the birefringent crystal for two laser oscillation modes whose directions of polarization are normal to each other differ from each other.

Polarization control element and solid state laser

A solid-state laser module made up of a solid-state laser crystal, a semiconductor laser for pumping purposes, and a resonator mounted on one surface of a mounting plate. A base plate is spaced apart from the mounting plate while facing the opposite side of the mounting plate to the module-mounted side. The base plate and the mounting plate are coupled together by means of at least one coupling member. A temperature control element for controlling the temperature of the solid-state laser module is interposed between the mounting plate and the base plate with elastic adhesive layers between the element and the mounting plate, and between the element and the base plate.

Laser-diode-pumped solid-state laser

A laser includes a laser medium, a light source for emitting light which pumps the laser medium, a pair of mirrors which are disposed on opposite sides of the laser medium and form a resonator, an etalon which is disposed in the resonator in order to make the oscillation mode of a laser beam a single longitudinal mode and a nonlinear optical crystal which is disposed in the resonator and converts the laser beam to a second harmonic. The effective thickness t of the etalon satisfies the condition that 2t(n.sub.SH -n.sub.FM)/.lambda..sub.SH is substantially an integer wherein .lambda..sub.SH represents the wavelength of the second harmonic, n.sub.FM represents the refractive index of the etalon for the fundamental wave and n.sub.SH represents the refractive index of the etalon for the second harmonic.

Laser

In an optical wavelength converting apparatus, a fundamental wave impinges upon a crystal of a nonlinear optical material, the type II of phase matching between the fundamental wave and its second harmonic is effected, and the second harmonic of the fundamental wave is thereby radiated out of the optical wavelength converting apparatus. Two crystals constituted of the same material are employed as the crystal. The two crystals have equal lengths and are located in orientations such that corresponding optic axes may be shifted 90.degree. from each other. The optical wavelength converting apparatus yields the second harmonic having the maximum possible output power and yet can be kept small in size and low in cost.

Optical wavelength converting apparatus

An optical wavelength converter that converts the wavelength of the fundamental wave emitted from a fundamental wave light source by causing the fundamental wave to enter a non-linear optical material. The converter has a filter that absorbs only one of two wavelength-converted waves which is emitted from the non-linear optical material in directions opposite to each other. In the converter, light transmission end faces of an element interposed between the filter and the non-linear are covered with an antireflection coating. Alternatively, instead of the filter, the converter has a reflecting optical element which reflects only one of two wavelength-converted waves which are emitted from the non-linear optical material in directions opposite to each other, and which causes the reflected wavelength-converted wave to travel along an optical path which does not return to the non-linear optical material. In this construction, the light transmission end faces of the element interposed between the filter and the non-linear are also covered with an antireflection coating with respect to the wavelength-converted waves. Thus, variations in an output of the wavelength-converted wave resulting from variations in the wavelength of the fundamental wave are prevented.

Optical wavelength converter

A single-longitudinal-mode laser comprises a laser medium, an etalon, and a resonator. The etalon is located in the resonator in a state such that two light passage end faces of the etalon, which are parallel to each other, may make a predetermined angle with respect to a resonator axis. The longitudinal mode of the etalon coincides with a gain peak wavelength of the laser medium. The single-longitudinal-mode laser is free from the problems in that the threshold value of the pumping power for the oscillation of the laser becomes large, in that the output power of the laser becomes low, in that the profile of the radiated beam becomes distorted, and in that the single longitudinal mode characteristics become bad.

Etalon and single-longitudinal-mode laser using the same

A solid laser medium is pumped by a semiconductor laser in order to produce a solid laser beam. The solid laser beam having thereby been obtained is caused to impinge upon a crystal of a nonlinear optical material, and the wavelength of the solid laser beam is thereby converted into a different wavelength. A nonlinear optical coefficient of the crystal of the nonlinear optical material utilized for the wavelength conversion is represented by d.sub.IJ, where I, J=1, 2, 3, and an principal axis of indicatrix of the nonlinear optical material corresponding to J is represented by .alpha.. The direction of linear polarization of a laser beam, which is produced by the semiconductor laser and serves as a pumping beam, is set in the direction, which coincides with the principal axis of indicatrix .alpha. when it is viewed from the direction of incidence of the pumping beam.

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Kanagawa, Japan

Chiaki Goto