Hitachi Metals, Ltd.

Hitachi, Ltd.

Hitachi Maxell, Limited

Nippon Ferrite, Ltd.

Hitachi Ferrite, Ltd.

Kohei Ito

Yasuhide Murakami

Masayoshi Sato

Shigeru Takeda

Fumio Nitanda

Yasuaki Kinoshita

Kenchi Ito

Satoshi Makio

Hisao Kurosawa

Sadami Kubota

Kimio Tatsuno

Tetsuo Andou

Kazumi Kawamoto

Osamu Komoda

Yasunori Furukawa

Hiroshi Momiji

Sten Helmfrid

Toru Abe

Kazutami Kawamoto

Masazumi Sato

Yasuhiro Furukawa

Noboru Abe

There is disclosed a harmonic modulation device of waveguide type including a semiconductor laser, a waveguide for generating a nonlinear optical harmonic of the semiconductor laser by keeping phase matching, means for leading an optical beam of the semiconductor laser to the waveguide, electrodes disposed on the waveguide, and means for modulating a refractive index of the waveguide electro-optically to modulate a phase matching condition and thereby modulate an intensity of the harmonic.

Short-wavelength laser light source

A battery-monitoring circuit includes a bidirectionally current-controllable means disposed between a secondary battery and a charging circuit or a load circuit for monitoring the charge or discharge of the secondary battery to prevent undesirable charging. The current control means has characteristics as an active diode, which is constituted by an error amplifier to which a predetermined voltage and voltage between both terminals of the current control means are supplied. The current control means supplies an output to the current-controllable means, such that the output of the current-controllable means is controlled constant, equal to the predetermined voltage.

Bi-direction current control circuit for monitoring charge/discharge of

Using an LiTaO.sub.3 or LiNbO.sub.3 substrate, a proton exchange layer in a grid pattern, namely sprout areas of polarization inversion, is firstly, formed on the surface of said substrate and, after formation of the pattern, heat treatment is executed at a temperature of 200.degree. C. or more and for a holding time of 10 minutes or less. By maintaining the temperature gradient up to said heat treatment point at 50.degree. C./min. or steeper and by maintaining the temperature decrease rate from said heat treatment point at 50.degree. C./min. or faster, polarization inverted areas are formed downwards from the proton exchanged areas, while in addition to making the top ends of said polarization inverted areas into an acute angle, the depth/weight ratio of the polarization inverted grids being formed is made to exceed 1, thus enabling the production of a high-efficiency SHG element.

Second harmonic generating element and the production method thereof

A circuit element utilizing magnetostatic is formed with an acoustic wave absorbing layer on the other major surface of a non-magnetic substrate remote from the major surface where a magnetostatic wave propagation medium is formed, for the purpose of effectively suppressing an unnecessary spurious mode over a wide frequency band so as to obviate undesirable degradation of the resonance characteristic. That is, the circuit element utilizing the magnetostatic wave includes a thin film of YIG formed on one of the major surfaces of the non-magnetic substrate of GGG by the method of liquid phase epitaxial growth, and electrodes formed on the YIG thin film. In the circuit element, an acoustic wave absorbing layer is formed on the other major surface of the GGG substrate remote from the major surface where the YIG thin film is formed.

Magnetostatic wave device containing acoustic wave absorbing layer

0.1% or more of Mg by weight is added to lithium tantalate monocrystal materials wherein the amount of Fe is restricted to 10 ppm by weight or less to improve light transmittance in the short wavelength range of blue light and to shift the fundamental absorption edge to the shorter wavelength.

Lithium tantalate monocrystal, monocrystal substrate, and photo element

In growing an oxide single crystal such as a garnet single crystal or ferrite single crystal by the liquid epitaxial process, the Bridgman process or the like, the melting-out of a platinum or platinum-based alloy-made crucible holding a melt for growing the crystal therefrom is prevented by bringing an electrode in contact with the melt or dipping the electrode into the melt in oxygen, air or an inert gas, applying electric current through the melt between the electrode and the metallic container and controlling the current so as to keep it at nearly zero.

Method of producing single crystal and apparatus therefor

A circuit element utilizing a magnetostatic wave is disclosed which uses a magnetostatic-wave resonator having a structure wherein a thin YIG (yttrium iron garnet) film is formed on a non-magnetic substrate such as a GGG (gadolium gallium garnet) substrate and defining a wave propagation plane. In this resonator, at least a part of end faces of the YIG film are inclined at an angle of 2.degree. or more to a plane perpendicular to the wave propagation plane to suppress the generation of unnecessary spurious modes in a wide frequency range.

Circuit element having ferrimagnetic film with deviated end surfaces for

A circuit element utilizing a magnetostatic wave is disclosed which uses a magnetostatic-wave resonator having a structure that a thin YIG (yttrium iron garnet) film is formed on a non-magnetic substrate such as a GGG (gadolinium gallium garnet) substrate. In this resonator, at least a part of end faces of the ferrimagnetic film are made rough such as by lapping with abrasives having a grain size greater than or equal to about 15 .mu.m, to suppress the generation of a unnecessary spurious mode in a wide frequency range.

Circuit element utilizing magnetostatic wave

A magnetostatic wave device has a nonmagnetic substrate, a magnetic thin film formed on the nonomagnetic substrate, and a plurality of electrodes. By applying a magnetic field from the outside in parallel with or perpendicularly to the magnetic thin film, a magnetostatic wave is excited in the magnetic thin film and is propagated. The magnetostatic wave is coupled with a microwave signal generating circuit by a plurality of (n) electrodes. The plurality which are arranged at positions where the microwave signal is not substantially coupled with the second to (n+l)th order mode of the magnetostatic wave.

Magnetostatic wave device with minimized higher order mode excitations

A magnetostatic wave device comprises a magnetic thin film formed on a non-magnetic substrate, one or a plurality of electrode fingers and pad electrodes formed on the above described magnetic thin film, a magnetostatic wave resonator for exciting and propagating a magnetostatic wave within said magnetic thin film and for causing resonance, and a matching stub connected to at least one of the above described pad electrodes of the above described magnetostatic wave resonator to adjust the impedance of the magnetostatic wave device.

Magnetostatic wave device

A chip for a magnetostatic wave device comprising; a base substrate consisting of a dielectric monocrystalline base plate and a ferrimagnetic monocrystalline film formed on the base plate; an excitation means for magnetostatic waves formed on the ferrimagnetic film when it is given a bias magnetic field and high frequency electric signals; and a reflection means to reflect the excited magnetostatic wave toward the center portion of the film before it reaches at end portions of the ferrimagnetic film.

Growing community of inventors

Fukaya, Japan

Kohei Ito