Abstract: A polarization-independent optical isolator includes a first birefringent wedge plate having an inclined plane directed to a light incoming side; a second birefringent wedge plate having an inclined plane directed to a light outgoing side, the wedge equal thickness line of the inclined plane of the second birefringent wedge plate being in parallel to the wedge equal thickness line of the inclined plane of the first birefringent wedge plate; and a Faraday rotator element disposed between the first and second birefringent wedge plates. A non-inclined plane of the first birefringent wedge plate is adhesively bonded to a light incoming plane of the Faraday rotator element, and a light outgoing plane of the Faraday rotator element is adhesively bonded to a non-inclined plane of the second birefringent wedge plate. The first and second birefringent wedge plates and the Faraday rotator element thus adhesively bonded to each other are disposed in a cylindrical magnet.

Abstract: There is disclosed a piezoelectric single crystal wafer wherein an etching pit density on the front surface of the wafer on which an electrode for transmit-receive of surface acoustic wave or leaky surface acoustic wave is formed is 7.8×104/mm2 or less, and a piezoelectric single crystal wafer wherein surface roughness Ra on the peripheral surface other than the front surface and the reverse surface of the wafer is 2.3 &mgr;m or less. There can be provided a piezoelectric single crystal wafer wherein a deviation of surface acoustic wave velocity or leaky surface acoustic wave velocity is small, namely the uniformity of the velocity is excellent, and fine contaminations adhered on the surface where electrode is formed and breakage of the wafer can be significantly reduced, and therefore a device such as a filter having excellent property can be produced in high yield.

Abstract: There is disclosed an optical isolator, wherein one surface of an optical element comprising at least one polarizer and at least one Faraday rotator is bonded and fixed to a substrate in which a height of an optical element bonded portion surface has a level difference from a height of a peripheral portion surface, and the optical isolator, wherein a rectangular parallelepiped optical element comprising at least one polarizer and at least one Faraday rotator, which are bonded in the face of each light-transmitting surface, is bonded and fixed with a bonding agent to the substrate while the Faraday rotator in the optical element is not bonded to the substrate. There is provided a reliable and low cost optical isolator that can bond and integrate an optical isolator element and permanent magnets on a substrate, can realize positional adjustment in assembly with high precision and high bonding strength, and can avoid bonding distortion for an optical element.

Abstract: A Faraday rotator whose Faraday's rotational angle has low temperature-dependency; a method for efficiently preparing the same; a magneto-optical element which makes use of the Faraday rotator and whose characteristic properties are not susceptive to temperature changes; and an optical isolator, which can be provided at a low price. A Faraday rotator consists of a garnet crystal represented by the following compositional formula and having a lattice constant of 12.470 ±0.013 Å: (Tb1−(a+b+c)LnaBibM1c)3(Fe1−dM2d)5O12 in the formula, Ln is an element selected from the group consisting of rare earth elements other than Tb; M1 represents an element selected from the group consisting of Ca, Mg and Sr; M2 is an element selected from the group consisting of Al, Ti, Si and Ge; and a to d are numerals satisfying the following relations: 0≦a≦0.5, 0<b≦0.2, 0≦c≦0.02 and 0≦d≦0.1.

Abstract: A piezoelectric single crystal wafer for SAW or LSAW devices has an x-ray rocking curve half width of up to 0.06° on the wafer surface on which electrodes are to be formed for transmitting and receiving SAW or LSAW.

Abstract: There is disclosed an optical isolator, wherein one surface of an optical element comprising at least one polarizer and at least one Faraday rotator is bonded and fixed to a substrate in which a height of an optical element bonded portion surface has a level difference from a height of a peripheral portion surface, and the optical isolator, wherein a rectangular parallelepiped optical element comprising at least one polarizer and at least one Faraday rotator, which are bonded in the face of each light-transmitting surface, is bonded and fixed with a bonding agent to the substrate while the Faraday rotator in the optical element is not bonded to the substrate. There is provided a reliable and low cost optical isolator that can bond and integrate an optical isolator element and permanent magnets on a substrate, can realize positional adjustment in assembly with high precision and high bonding strength, and can avoid bonding distortion for an optical element.

Abstract: Herein provided is an optical isolator which permits the reduction of the production cost and which is excellent in the thermal shock resistance. The optical isolator of the present invention is that the Farady rotator be adhered to the birefringent crystals or glass polarizers through adhesive layers and that the glass transition point of the adhesive be not more than −40° C.

Abstract: A magnetostatic wave device includes a Gd3Ga5O12 substrate off-angled from a {110} plane. A magnetic thin film including a crystal of garnet is formed on the Gd3Ga5O12 substrate by liquid-phase epitaxy. A transducer operates for exciting magnetostatic wave in the magnetic thin film in response to an RF electric signal. A bias magnetic field is applied to the magnetic thin film. There is a relation as 20°≦|&thgr;1+&thgr;2|≦35°, where “&thgr;1” denotes an angle between a longitudinal direction of the transducer and a <001> orientation of the crystal in the magnetic thin film, and “&thgr;2” denotes an angle between a transverse direction of the transducer and a specified direction.

Abstract: An improvement is proposed relating to an optical isolator for bonding of the polarizer and analyzer of polarizing glass to the respective holder rings for position adjustment. The improvement comprises: (a) forming a metallized layer of a specific composition over at least two of the side surfaces of each of the polarizer and analyzer on the area of the surface excepting for the linear areas of 50 to 150 .mu.m width from the top and bottom surfaces of the polarizer or analyzer; and (b) bonding the polarizer and analyzer to the respective holder rings by soldering using a solder alloy with intervention of the metallized layer between the polarizer or analyzer and the holder ring. The invention further provides an optical part having, on at least one of the surfaces, a heat-resistant anti-reflection coating film which is a double-layered film consisting of a thin film of the titanium oxide TiO.sub.x (x=1.9 to 2.

Abstract: The present multiple-stage optical isolator has low polarization-dependency and low polarization-mode dispersion but does not require a long time for the assembly. It is constructed of a first unit having a first Faraday rotator placed within a magnetic field and at least one birefringent crystal sandwiching the Faraday rotator, these components being arranged in order from the light incident side; and a second unit having a second Faraday rotator placed within a magnetic field and at least one birefringent crystal sandwiching the Faraday rotator, these components being arranged in order from the light incident side, wherein the first and second units are arranged in order along the direction of the light transmission.

Abstract: An optical isolator has a high ratio of the quantity of signals S to that of noises N (S/N ratio) and can be miniaturized such a size that it can easily be incorporated into a laser module. The optical isolator 1 according to the present invention is one to be connected to a semiconductor laser 11 having a linear polarization plane and comprises a Faraday's rotator 5 and a magnetic material 4 for establishing a magnetic field around the rotor on the light-incident side of the isolator and an optical material 6 for polarization on the light-outputting side thereof.

Abstract: A magnetostatic wave device includes a Gd.sub.3 Ga.sub.5 O.sub.12 substrate off-angled from a {110} plane. A magnetic thin film including a crystal of garnet is formed on the Gd.sub.3 Ga.sub.5 O.sub.12 substrate by liquid-phase epitaxy. A transducer is operative for exciting magnetostatic wave in the magnetic thin film in response to an RF electric signal. A bias magnetic field is applied to the magnetic thin film. There is a relation as 20.degree..ltoreq..vertline..theta..sub.1 +.theta..sub.2 .vertline..ltoreq.35.degree., where ".theta..sub.1 " denotes an angle between a longitudinal direction of the transducer and a <001> orientation of the crystal in the magnetic thin film, and ".theta..sub.2 " denotes an angle between a direction of the bias magnetic field and a transverse direction of the transducer which is perpendicular to the longitudinal direction thereof.

Abstract: A reflection-type S/N enhancer includes a Gd.sub.3 Ga.sub.5 O.sub.12 substrate off-angled from a {110} plane. A magnetic thin film including a crystal of garnet is formed on the Gd.sub.3 Ga.sub.5 O.sub.12 substrate by liquid-phase epitaxy. The magnetic thin film has a saturation magnetization in a range of 500 G to 1,100 G. A transducer is operative for exciting magnetostatic wave in the magnetic thin film in response to an RF electric signal. A bias magnetic field is applied to the magnetic thin film. There is a relation as .vertline..theta..sub.1 +.theta..sub.2 .vertline.<45.degree., where ".theta..sub.1 " denotes an angle between a longitudinal direction of the transducer and a <001> orientation of the crystal in the magnetic thin film, and ".theta..sub.2 " denotes an angle between a direction of the bias magnetic field and a transverse direction of the transducer in a horizontal plane. The transverse direction of the transducer is perpendicular to the longitudinal direction thereof.

Abstract: An improvement is proposed relating to an optical isolator for bonding of the polarizer and analyzer of polarizing glass to the respective holder rings for position adjustment. The improvement comprises: (a) forming a metallized layer of a specific composition over at least two of the side surfaces of each of the polarizer and analyzer on the area of the surface excepting for the linear areas of 50 to 150 .mu.m width from the top and bottom surfaces of the polarizer or analyzer; and (b) bonding the polarizer and analyzer to the respective holder rings by soldering using a solder alloy with intervention of the metallized layer between the polarizer or analyzer and the holder ring. The invention further provides an optical part having, on at least one of the surfaces, a heat-resistant anti-reflection coating film which is a double-layered film consisting of a thin film of the titanium oxide TiO.sub.x (x=1.9 to 2.

Abstract: Proposed is an improvement in a magnetostatic surface wave device such as an S/N enhancer comprising a thin film chip of a magnetic oxide garnet, e.g., gallium-substituted YIG epitaxially grown on the surface of a substrate, e.g., GGG, to which a magnetic field is applied within the plane of the thin film. The low-pass cut-off frequency of the microwaves can be decreased to 400 MHz or lower and the half-value width of magnetic resonance .DELTA.H can be small enough when the principal plane of the thin film of the magnetic oxide garnet is the (110) plane and the magnetic field applied thereto is in such a direction that the angle between the direction of the magnetic field and the direction of the <100> axis of the thin film within the (110) plane is in the range from .+-.27.degree. to .+-.33.degree..

Abstract: Proposed is an improvement in the method for the preparation of a chip of an oxide garnet film epitaxially having a specific chemical composition as grown on the surface of a GGG substrate wafer having a crystallographic plane orientation of (111), which is useful as a working element in a magnetostatic wave device such as high-frequency filters, signal noise enhancers, isolators and the like with decreased temperature dependence of the properties. The epitaxially grown single crystal film is adjusted to have such dimensions that the thickness h and the smallest dimension L within the plane of the film satisfy the relationship that the ratio h/L is in the range from 0.001 to 0.25.

Abstract: A novel rare earth-based oxide garnet single crystal suitable as a material of the elements in a magneto-optical device to exhibit a greatly decreased light absorption loss is proposed, which is prepared by the liquid epitaxial growth method on a oxide garnet single crystal wafer and having a chemical composition represented by the general formulaGd.sub.a Ho.sub.b Eu.sub.d Bi.sub.3-a-b-d Fe.sub.5-c M.sub.c O.sub.12,in which M is an element or a combination of elements selected from the group consisting of aluminum, scandium, gallium and indium, the subscript a is a positive number in the range from 1.1 to 2.1, the subscript b is a positive number in the range from 0.1 to 0.9, the subscript c is 0 or a positive number not exceeding 0.5 and the subscript d is zero or a positive number not exceeding 0.6 or, in particular, in the range from 0.03 to 0.6 with the proviso that 3-a-b-d is in the range from 0.7 to 1.2.

Abstract: A radiant ray-detector having a high resolving ability and capable of being easily produced as well as a method for producing the same are herein disclosed. The radiant ray-detector comprises a plurality of photomultiplier tubes 11 combined together and scintillator chips 1, wherein the scintillator chips 1 each is in the form of a hexahedron, more than one face thereof is mirror finished, the other faces are surface-toughened and a number of these scintillator chips 1 greater than the number of the photomultiplier tubes 11 are joined together so that the overall area of the resulting mirror surface of a group of scintillator chips 1 is approximately identical to the area of an entrance window 12 of each corresponding photomultiplier tube 11 and wherein different transmittances are imparted to individual coarse faces 4 of the scintillator chip 1 joined to those of other scintillator chips.

Abstract: An optical fiber type part for optical systems which comprises a smaller number of parts, whose production does not require a long time and which has stable optical characteristics is herein provided. The optical fiber type part for optical systems comprises an optical element 9, first and second lenses and each arranged on the light-incident or light-outgoing side of the optical part and first and second optical fibers and each arranged on the light-incident side of the first lens and the light-outgoing side of the second lens respectively and is characterized in that the end faces of the first and second optical fibers which are opposed to one another are inclined at an angle and subjected to abrasive finishing and that anti-reflection films are formed on these end faces.

Abstract: Proposed is an improved optical waveguide consisting of a substrate plate such as a silicon wafer, an undercladding layer of silica glass thereon, a core line of silica glass extending on the undercladding layer and having a larger refractive index than the undercladding layer and an overcladding layer of silica glass having a smaller refractive index than the core line to cover the undercladding layer and the core line thereon altogether. Different from conventional optical waveguides of this type, of which each of the undercladding layer, core line and overcladding layer is formed by the flame deposition method of silica or electron-beam vapor deposition method followed by vitrification taking a relatively long time, the overcladding layer in the inventive optical waveguide is formed by forming a layer of an organopolysiloxane resin on the undercladding layer and core line followed by the oxidative thermal decomposition of the resin into silica and vitrification of the same.