Abstract: A method and apparatus for optically isolating multiple core optical fibers while at the same time substantially reducing polarization mode dispersion, is disclosed. A multiple core fiber is optically coupled to optical birefringent elements, reciprocal and non-reciprocal rotators, and through a lens assembly to a multiple core optical fiber output.

Abstract: A stereoscopic image pickup system for obtaining parallactic images of an object, the stereoscopic image pickup system includes a pair of, first and second, reflecting members each having a reflecting function, a pair of, first and second, amount-of-light control members arranged to respectively vary amounts of transmission of light fluxes coming from the first and second reflecting members alternately in a time-series manner, an optical member arranged to superpose an optical axis of a light flux having passed through the first reflecting member and the first amount-of-light control member and an optical axis of a light flux having passed through the second reflecting member and the second amount-of-light control member on one and the same optical axis, an image sensor for converting a light flux coming from the optical member into an electrical signal, and a controller for causing, on the basis of information on a distance to the object, an image taking-in area of the image sensor to differ between a first

Abstract: A spatial light modulation device is formed by creating at least one movable element, fixedly attached to the substrate at a first end, from a soft magnetic material with an anisotropic stress created within the movable element such that the element exists in a first position as a result of the anistropic stress and an actuating device comprising a magnetic layer placed within close correspondence with the soft magnetic material for placing the soft magnetic material into a second position.

Abstract: A variable optical attenuator comprises a Faraday rotator including a ferromagnetic garnet film disposed input/output single mode optical signal paths. A collimating/lensing arrangement is used to focus the optical signal between the input/output signal paths and the ferromagnetic garnet film. The ferromagnetic material exhibits multiple types of magnetic domain such that an optical signal will experience ±rotation as its passes through the film. A 90° garnet film thus provides ±90° rotation, resulting in a fill 180° directional difference between the optical signal components. The amplitudes of these signals will thus cancel, providing an essential “full” attenuation of the optical signal. The application and adjustment of a magnetic field to the garnet film controls the strength (i.e.

Abstract: An optical switch includes a light emitter for emitting light and light receivers. A reflector is used for changing a path of light emitted from the light emitter. The reflector is held by a permanent magnet having first and second magnetic poles of opposite polarities. A supporting member is provided for the reflector and the first permanent magnet so that the reflector and the first permanent magnet can move between a first position and a second position. In the first position, the reflector and the first permanent magnet interact so the emitted light travels into one light receiver of the light receivers. On the other hand, in the second position, the reflector and the first permanent magnet interact so the emitted light travels into another of the light receivers. The switch further includes an electromagnet for generating first and second magnetic fields selectively for moving the reflector and the first permanent magnet between the first and second positions.

Abstract: A low magnetic saturation type bismuth-substituted rare-earth iron garnet crystal film of the invention is grown on a substrate of (111) garnet single crystal (GdCa)3(GaMgZr)5O12 by using a liquid phase epitaxial method. This single crystal has a lattice constant of 1.2497.+-.0.0002 nm and has a chemical structural formula expressed byTb.sub.3-x Bi.sub.x Fe.sub.5-y-z Ga.sub.y Al.sub.z O.sub.12wherein x has the range 1.25<.times.<1.40, y+z has the range 0.50<y+z<0.65, and z/y has the range 0.45<z/y<0.75.

Abstract: In an arrangement substantially like an optical isolator, appropriate choice of the composition of the magneto-optic element can result in a variable optical attenuator. The composition is selected to vary in the direction of light propagation, and also is selected such that the magneto-optic element comprises a compensation wall. The compensation wall is movable in response to a change in the temperature of the magneto-optic element, whereby the attenuation of the device is changed.

Abstract: An apparatus which attenuates a light signal polarized in a first direction. The apparatus includes a polarization rotation unit and an output unit. The polarization rotation unit rotates the polarization of the light signal to produce a polarization rotated light signal having a polarization component in the first direction and a polarization component in a second direction which is substantially 90 degrees with respect to the first direction. The output unit passes, as an output signal, the polarization component in the second direction of the polarization rotated light signal and blocks the polarization component in the first direction. The polarization rotation unit includes an electromagnet and a permanent magnet which apply magnetic fields in specific directions with respect to the light path. Various yoke constructions are provided for the electromagnet and the permanent magnet.

Abstract: A Faraday rotator is formed of a bismuth-substituted iron garnet single crystal film on which an antireflection film is formed. The antireflection film includes first, second, and third layers. The first layer is a layer of silicon dioxide. The second layer is a layer of tantalum pentoxide. The third layer is a layer of silicon dioxide. The first, second, and third layers are formed in this order from the atmosphere side on the bismuth-substituted iron garnet single crystal film. The antireflection film may be formed on both of opposing surfaces of the single crystal film.

Abstract: A Faraday rotator is formed of a bismuth-substituted iron garnet single crystal film grown by a liquid phase epitaxial method. The single crystal film is represented by a formula: Tb.sub.3-x Bi.sub.x Fe.sub.5-y-z Ga.sub.y Al.sub.z O.sub.12 wherein x has the range 1.1.ltoreq.x.ltoreq.1.5, y+z has the range 0.65.ltoreq.y+z.ltoreq.1.2, and z has the range z.ltoreq.y. The bismuth-substituted rare earth single crystal film is subjected to a magnetization process where the single crystal film is magnetized by an external magnetic field so that the film has a square magnetic hysteresis loop. The external magnetic field has a magnetic field strength of 1,000 Oe or higher and is applied in a direction normal to a surface of the bismuth-substituted rare earth iron garnet single crystal film.

Abstract: An apparatus which attenuates a light signal polarized in a first direction. The apparatus includes a polarization rotation unit and an output unit. The polarization rotation unit rotates the polarization of the light signal to produce a polarization rotated light signal having a polarization component in the first direction and a polarization component in a second direction which is substantially 90 degrees with respect to the first direction. The output unit passes, as an output signal, the polarization component in the second direction of the polarization rotated light signal and blocks the polarization component in the first direction. The polarization rotation unit includes an electromagnet and a permanent magnet which apply magnetic fields in specific directions with respect to the light path. Various yoke constructions are provided for the electromagnet and the permanent magnet.

Abstract: A magneto-optical element comprises a film of a Bi-substituted rare earth iron garnet selected from garnets of the following chemical formulas(Bi.sub.x Gd.sub.y R.sub.z Y.sub.3-x-y-z)(Fe.sub.5-w Ga.sub.w)O.sub.12wherein R represents at least one element selected from the group consisting of rare earth elements other than Gd, and x, y, z and w are such that 1.00.ltoreq.x.ltoreq.1.30, 0.42.ltoreq.y.ltoreq.0.60, 0.01.ltoreq.z.ltoreq.0.05 and 0.40.ltoreq.w.ltoreq.0.62, and(Bi.sub.x' Gd.sub.y' R.sub.z' Y.sub.3-x'-y'-z')Fe.sub.5 O.sub.12wherein R is as defined above, and x', y' and z' are such that 1.10.ltoreq.x'.ltoreq.1.30, 1.00.ltoreq.y'.ltoreq.1.80, 0.ltoreq.z'.ltoreq.0.06. An optical magnetic field sensor capable of detecting zeroth to higher order beams of diffracted light is also described.

Abstract: A Faraday rotator which includes a magnetic optical element and a magnetic field generating unit. The magnetic optical element has an optical path extending therethrough. The magnetic field generating unit is positioned so as not to obstruct the optical path, and generates a uniform magnetic field in the magnetic optical element. The magnetic field generating unit can include a first magnet unit and a second magnet unit. The first magnet unit is positioned so as not to obstruct the optical path and generates a magnetic field passing through the magnetic optical element. The second magnet unit is positioned so as not to obstruct the optical path and generates a magnetic field passing through the magnetic optical element. The magnetic field generated by the second magnet unit is perpendicular to the magnetic field generated by the first magnet unit and combines with the magnetic field generated by the first magnet unit to produce a uniform magnetic field in the magnetic optical crystal.

Abstract: A magneto-optical element comprises a film of a Bi-substituted rare earth iron garnet selected from garnets of the following chemical formulas(Bi.sub.x Gd.sub.y R.sub.z Y.sub.3-x-y-z)(Fe.sub.5-w Ga.sub.w)O.sub.12wherein R represents at least one element selected from the group consisting of rare earth elements other than Gd, and x, y, z and w are such that 1.00.ltoreq.x.ltoreq.1.30, 0.42.ltoreq.y.ltoreq.0.60, 0.01.ltoreq.z.ltoreq.0.05 and 0.40.ltoreq.w.ltoreq.0.62, and(Bi.sub.x 'Gd.sub.y 'R.sub.z 'Y.sub.3-x'-y'-z')Fe.sub.5 O.sub.12wherein R is as defined above, and x', y' and z' are such that 1.10.ltoreq.x'.ltoreq.1.30, 1.00.ltoreq.y'.ltoreq.1.80, 0.ltoreq.z'.ltoreq.0.06. An optical magnetic field sensor capable of detecting zeroth to higher order beams of diffracted light is also described.

Abstract: A Faraday rotator which comprises, in combination, a garnet material of an atomic ratio compositionBi.sub.x P.sub.y Q.sub.3-x-y Fe.sub.5-w M.sub.w O.sub.12in which P is one or more elements chosen from among Y, La, Sm, Eu, Tm, Yb, and Lu, Q is one or more elements chosen from among Gd, Tb, Dy, Ho, and Er, M is one or more nonmagnetic elements that can substitute for Fe, and 0.7.ltoreq.x.ltoreq.2.0, 0.5.ltoreq.y.ltoreq.2.3, 0.ltoreq.3-x-y.ltoreq.1, and 0..ltoreq.w.ltoreq.1.0, and a magnet for applying a magnetic field smaller than the saturation magnetic field to said material. Preferably, the value w ranges from 0.2 to 0.7, and a Faraday rotator especially excellent is one using a garnet material in which M.sub.w is represented by A.sub.k D.sub.l where A is an element to be substituted for the site a of the garnet, selected, e.g., from among Sc, In, etc., D is an element to be substituted for the site d of the garnet, selected, e.g., from among Ga, Al etc., and 0.ltoreq.k<0.1, 0.2.ltoreq.l.ltoreq.0.

Abstract: In a magnetooptical element comprising a single crystal of Cd.sub.1-x-y Mn.sub.x Hg.sub.y Te, the single crystal has a composition in an area defined in a quasi three-element phase diagram of MnTe--HgTe--CdTe by four points of:Mn.sub.0.01 Hg.sub.0.04 Cd.sub.0.95 Te, Mn.sub.0.01 Hg.sub.0.1 Cd.sub.0.89 Te, Mn.sub.0.12 Hg.sub.0.17 Cd.sub.0.71 Te, and Mn.sub.0.25 Hg.sub.0.04 Cd.sub.0.71 Te.This renders the magnetooptical element suitable for use in a wavelength range between 0.8 micrometer and 1.1 micrometers.

Abstract: Disclosed is a material for a magneto-optical element, which is made of magnetic garnet single crystals being wide in a band width in a 1310 nm band and thereby being capable of coping with the wavelength multiplex communication at the wavelength band, and a Faraday rotator using the same. The material for a magneto-optical element is made of a magnetic garnet having a composition formula expressed by R.sub.3-y-x Sm.sub.y Bi.sub.x Fe.sub.5 O.sub.12, where R is one kind of rare earth elements including yttrium (Y), and "x" and "y" are constants defined by 0.3.ltoreq.x.ltoreq.1.9 and 0.4.ltoreq.y.ltoreq.2.7, the magnetic garnet being formed on a non-magnetic substrate by liquid-phase epitaxial growth. R is preferably one of Y, La, Sm and Lu. The Faraday rotator, which is used in a wavelength range of from 1250 to 1370 nm, is formed by superposing a film A made of LPE magnetic garnet single crystals expressed by a composition formula of R1.sub.3-x Bi.sub.x Fe.sub.5-z Z.sub.z O.sub.

Abstract: A bismuth-substituted rare earth iron garnet single crystal grown on a non-magnetic substrate having a lattice constant of 12.490 .ANG.-12.510 .ANG. by the liquid phase epitaxial method, and represented by a general equation:Gd.sub.x R.sub.y Bi.sub.3-x-y Fe.sub.5-z-w Ga.sub.z Al.sub.w O.sub.12where R denotes at least one element selected from the group consisting of yttrium (Y), ytterbium (Yb) and lutetium (Lu), and x, y, z and w are numerical values in the ranges 0.50.ltoreq.y/x.ltoreq.1.35, 1.40.ltoreq.x+y.ltoreq.1.90, 0.0.ltoreq.w/z.ltoreq.0.3 and 0.7.ltoreq.z+w.ltoreq.1.25. The magneto-optic optical switch or Faraday rotator constituted by the bismuth-constituted rare iron garnet is stably operable in a temperature range of -20.degree. C. to 60.degree. C. Because of the saturated magnetic field is 160 (Oe) or less, a magnetic field application device necessary to invert the magnetic field can be miniaturized.

Abstract: A Faraday's rotator comprises a magnetic crystal which has a composition represented by the following compositional formula: (Tb.sub.1-(a+b+c+d) Ln.sup.1.sub.a Ln.sup.2.sub.b Bi.sub.c M.sup.1.sub.d).sub.3 (Fe.sub.1-e M.sup.2.sub.e).sub.5 O.sub.12, has a lattice constant of 12.383.+-.0.006 .ANG. and is grown through the liquid phase epitaxial growth technique. In the foregoing formula, Ln.sup.1 is at least one element selected from the group consisting of Yb, Lu and Tm; Ln.sup.2 is at least one member selected from the group consisting of rare earth elements except for Yb, Lu, Tm and Tb; M.sup.1 is at least one element selected from the group consisting of Ca, Mg and Sr; M.sup.2 is at least one element selected from the group consisting of Al, Ga, Ti, Si and Ge; 0.2.ltoreq.a.ltoreq.0.6, 0.ltoreq.b.ltoreq.0.3, 0 <c.ltoreq.0.16, 0<d.ltoreq.0.02 and 0<e.ltoreq.0.1. Another Faraday's rotator comprises a magnetic crystal having a composition represented by the following compositional formula: (Tb.sub.

Abstract: In a polarization-state converting apparatus for use as an optical isolator, an optical modulator and the like, there are provided a waveguide including a magnetic semiconductor, a device for applying a magnetic field to the waveguide in a first predetermined direction, a device for applying an electric field to the waveguide in a second predetermined direction, and a mode conversion is caused via electrooptic and magnetooptic effects due to the electric and magnetic fields to change the polarization state of light propagating through the waveguide. When used as an optical isolator, the optical isolation is performed to compensate for degradation of the mode conversion rate due to a phase mismatch between light incident upon the waveguide and light emerging from the waveguide.

Abstract: The optical isolator of the present invention comprises a polarizer, a Farady rotator and an analyzer arranged in this order, wherein the Farady rotator has a garnet crystalline structure represented by the formula (Tb.sub.1-(a+b) Ln.sub.a Bi.sub.b).sub.3 (Fe.sub.1-c M.sub.c).sub.5 O.sub.12 wherein Ln represents at least one element selected from the group consisting of rare earth elements other than Tb; 0<a.ltoreq.0.6; 0<b .ltoreq.0.2; M represents at least one element selected from the group consisting of Al and Ga; and 0.ltoreq.c<0.1; or the formula (Tb.sub.1-(d+e+b) Ln.sub.d Eu.sub.e Bi.sub.b).sub.3 (Fe.sub.1-c M.sub.c).sub.5 O.sub.12 wherein Ln represents at least one element selected from the group consisting of rare earth elements other than Tb and Eu; 0<d<0.6; 0<e.ltoreq.0.2; 0<d+e.ltoreq.0.6; 0<b.ltoreq.0.2; M represents at least one element selected from the group consisting of Al and Ga; and O.ltoreq.C<0.1; or the formula (Y.sub.1-(a+b) Ln.sub.a Bi.sub.b).sub.3 (Fe.sub.

Abstract: An optical sensor excellent in reliability and mass producibility and low in cost, by forming a magnetic optical crystal, polarizer and analyzer monolithically on the same substrate.