Abstract: Disclosed herein is a multi-pole magnetic geometry for a multi-oscillator ring laser gyroscope. Multi-pole magnetic geometry configurations are disclosed which are useful for providing Faraday rotation where the multi-oscillator uses a Faraday rotator and high magnetic field effect where the nature of the multi-oscillator ring laser gyroscope is of split gain configuration. The multi-post magnetic geometry includes a plurality of top or bottom loaded diametrically opposed north and south pole axially directed magnets which are positioned substantially transverse to the optical pathway but suitable for providing axially directed magnetic fields to portions of the optical pathway only where desired. The multi-pole magnetic geometry disclosed herein substantially produces a magnetic flux that is restricted in its position to localized portions of the optical pathway with low far field effects.

Abstract: A reflection type magnetooptic sensor head is disclosed. The respective structural elements are aligned following a light source in the order of a light inputting/outputting path, polarizer, Faraday rotator, and reflecting mirror. The Faraday rotator is made of a (111) bismuth-substituted iron garnet single crystal film having [111] axis at an angle of 5-60 degrees with an axis normal to the film surface. The reflecting mirror is positioned such that a light incident upon the reflecting mirror is substantially normal to the surface of the reflecting mirror.

Abstract: An element for an optical isolator which is formed by alternately bonding together at least one flat plate-shaped Faraday rotator and two or more flat plate-shaped polarizers, the optical isolator element having an outer peripheral surface which is cut such that, when the outer peripheral surface is disposed parallel to an optical axis, incidence and emergence planes of the element are inclined at a predetermined angle with respect to a plane perpendicular to the optical axis. The optical isolator element is accommodated in a cylindrical magnet having an inner peripheral surface of the same shape as the outer peripheral surface of the optical isolator element, thereby forming an optical isolator.

Abstract: An optical isolator according to the invention comprises a first birefringent element for separating an incident light beam into two light beams that are vertical to each other in the polarization direction and are not parallel with each other in the propagation direction, a 45.degree. Faraday rotator, a second birefringent element that is identical with the first birefringent element in terms of the light beam-separation angle but is different by 45.degree. from the first polarizer in terms of the angle the separated two light beams make to the polarization of the beams, and at least one birefringent crystal plane plate that has a function capable of converging two parallel light beams, with the planes of polarization at right angles with each other, into a single beam.

Abstract: An optical device which optically connects a first and a second optical fiber with an optical path provided therebetween and has two or more functions including the function of an optical isolator. A beam of parallel rays obtained by having a beam from an excitation end of a first optical fiber collimated by a lens is passed through a double refraction element, a magnetooptic element, and a double refraction element in order of mention and converged by a lens to be introduced to a second optical fiber through its excitation end, while a beam from the second optical fiber is not coupled to the first optical fiber. Meanwhile, a beam from an excitation port is coupled to the first optical fiber. The optical device is suitable for use in an optical amplification system and a two-way optical transmission system.

Abstract: There is provided an optical circulator (16) for bidirectional communication on a fiber optic communication transmission system. Polarization preserving single-mode fiber lengths (26), (28) connect all-fiber polarization splitter (18) with the Faraday single-mode fiber lengths (22), (24). Polarization preserving single-mode fiber lengths (30), (32) connect the opposite ends of Faraday single-mode fiber lengths (22), (24) with all-fiber polarization splitter (20). A communication transmitter is connected to splitter (18) at port 1, and a communication receiver is connected to splitter (18) at port 3. A fiber optic communication link (50) is connected to splitter (20) at port 2. The components of optical circulator (16) cooperate such that light transmitted into port 1 exits from port 2, and light transmitted into port 2 exits from port 3.

Abstract: A reflective magneto-optic spatial light modulator (MOSLM.TM.) assembly has a nonmagnetic protective housing that receives, positions, and protects a spatial light modulator (SLM) chip that is formed from relatively fragile magneto-optic material from deformations caused by mechanical stress and by excessive temperature changes. The assembly further has a channelled ingress and egress of incident electromagnetic radiation, such as visible and coherent light, to and from the SLM chip.

Abstract: An optical isolator comprises a polarizer, a Faraday rotator, an analyzer and a magnet for applying a magnetic field to the Faraday rotator wherein the polarizer is incorporated into a first metal cylinder to form a polarizer unit, the Faraday rotator is incorporated into a cylindrical magnet to form a Faraday rotator unit and the analyzer is incorporated into a second metal cylinder to form an analyzer unit, the polarizer, Faraday rotator and analyzer units being arranged within an outer cylinder and the first metal cylinder and the second metal cylinder being joined to the outer cylinder through an adhesive component. The optical isolator can easily be produced, the adhered and supported portion thereof is not peeled off and it has high reliability.

Abstract: A non-reciprocal unit and a parallel-surfaced flat birefringent plate are provided between incident side and outgoing side fiber collimators. The non-reciprocal unit is formed by disposing two tapered birefrigent plates, one on each side of a 45.degree. Faraday rotator consisting of a cylindrical permanent magnet and a magneto-optical element housed in the magnet. The optical axes of the parallel-surfaced flat birefringent plate and adjacent tapered birefringent plate are staggered from each other by 90.degree.. The thickness of the parallel-surfaces birefringent plate is set equal to the sum of the thicknesses of the two tapered birefringent plates.

Abstract: A polarizer, a Faraday rotator and an analyzer are fixed by fused glass applied on an outer periphery of the polarizer to be contacted with the Faraday rotator and on an outer periphery of the analyzer to be contacted with the Faraday rotator. No adhesive exists between contact planes of the polarizer and the Faraday rotator and those of the Faraday rotator and the analyzer.

Abstract: A compound semiconductor device and a process for manufacturing it is disclosed. The process comprises the steps of forming a first conduction type first clad layer, a first conduction type or second conduction type activated layer, a second conduction type second clad layer, and a second conduction type cap layer upon a first conduction type semiconductor substrate, forming a first conduction type electrode and a second conduction type electrode, and forming a rectangular pole shaped laser diode, a triangular pole shaped detecting photo-diode, and a triangular pole shaped receiving photo-diode by carrying out a single round of anisotropic etching. According to the present invention, the high density can be easily realized, so that the power consumption and the manufacturing cost can be saved.

Abstract: A high-output optical transmitter including a rare earth-doped fiber. The optical transmitter includes a signal light source for outputting signal light having a first predetermined plane of polarization and a pumping light source for outputting pumping light having a second predetermined plane of polarization. The plane of polarization of the signal light from the signal light source is rotated 45 degrees by a Faraday rotator such that the plane of polarization of the signal light output from the Faraday rotator and the pumping light are perpendicular to each other. The signal light from the Faraday rotator and the pumping light from the pumping light source are polarization-coupled by a polarization coupler and the combined light is introduced into the rare earth-doped fiber.

Abstract: An apparatus for creating an optical noise of a predetermined bandwidth that uses an optical amplifier which amplifies optical noise components and produces unpolarized optical noise by spontaneous emission, a mirror to reflect the optical noise components back to the optical amplifier and a filter that filters out optical noise components outside the predetermined optical bandwidth. The filter is located so that optical noise components passed by the filter are amplified in the optical amplifier during an additional amplification. Optionally, a polarizer and Faraday rotator are used in the apparatus. The optical noise created in the optical amplifier is polarized in the polarizer after two amplifications, rotated in the Faraday rotator, then amplified two more times before leaving the apparatus.

Abstract: A polarimetric directional field sensor comprises an emitter and receiver (1) of measurement signals, connected by optical fibers (2, 2a, 2b) to a portable probe (3). The probe (3) comprises an optical element (11, 13) sensitive to the field to be measured and means (9, 20) for polarizing the measurement signal. The optically sensitive element (11, 13) is in the form of a birefringent crystal having a crystalline structure which provides at least one plane in which the induced birefringence is modified by a single component of the field to be measured. The crystal is cut and oriented in the probe so that the direction of propagation of the optical measurement signal inside the crystal is normal to this plane, the polarizing means (9, 20) being oriented at 45.degree. to the orthogonal axes in which the crystal's refractive indices are modified by the desired component of the field.

Abstract: An optical system in which optical circulators with polarization plates are used for light modulation of plane polarized light waves. The light modulation is used for black and white printing, grey scale printing and for adjustment of beam intensity of plane polarized light waves.

Abstract: An optical isolator having a combination of rutile plates or other birefringent crystals and Faraday elements. This optical isolator includes, arranged in the stated order along an optical axis, a first birefringent crystal; a first Faraday element for rotating a plane of polarization 45.degree.; a second birefringent crystal having an optic axis rotated 45.degree. with respect to the first birefringent crystal, and a thickness .sqroot.2 times a thickness of the first birefringent crystal; a third birefringent crystal having an optic axis rotated 135.degree. with respect to the first birefringent crystal, and a thickness .sqroot.2 times the thickness of the first birefringent crystal; a second Faraday element for rotating the plane of polarization 45.degree.; and a fourth birefringent crystal having an optic axis rotated 180.degree. with respect to the first birefringent crystal, and a thickness equal to the thickness of the first birefringent crystal.

Abstract: An optical circulator which includes a first birefringent plate for receiving an incident beam of light from a first port, a Faraday rotator, a polarization transforming device, and a second birefringent plate immediately adjacent a second port and the polarization transforming device. The optical circulator further includes means for diverting light traveling from the second port to a direction of travel which is at a right angle to the prior direction of travel, whereby the light is directed to a third port. The diverting means is immediately adjacent the first birefringent plate and the first port, and permits the clear passage of light from the first port to the first birefringent plate. The optical circulator has a simplified design while providing for the efficient transmission of polarized light.

Abstract: The optical circulator according to the present invention comprises three birefringent crystal plates 22, 23, and 24; reciprocal and non-reciprocal rotators 25 of the first group inserted between birefringent crystal plates 22 and 23; reciprocal and non-reciprocal rotators 26 of the second group inserted between birefringent crystal plates 23 and 24; and more than two beam incoming and outgoing ports 27, 28, and 29. The rotating directions of the reciprocal and non-reciprocal rotators 25 of the first group are so set that the directions in which ordinary beam and extraordinary beam are separated on the birefringent crystal plates differ among birefringent crystal plate 23 and birefringent crystal plates 22 and 24, and the electric field vibration directions of the beams agree at birefringent crystal plate 23.

Abstract: First and second beam splitters are arranged on the optical path of a light beam emerging from a recording surface, and such that the phases and amplitudes of the respective polarized light components of a light beam incident thereon are changed to equal extends. As a result of this arrangement, the state of polarization beam of the light beam emerging from the recording surface is maintained when a light beam is outputted through the two beam splitters. Stable reproduction signals and servo control signals for focusing, tracking, and the like can be reliably supplied by utilizing an apparatus of this invention.

Abstract: An optical isolator according to the present invention comprises a first polarizer, a Faraday rotator and a second polarizer which are adhered to one another in this order and held in a cylindrical magnet, wherein at least one adhered and supported portion comprises a low melting point glass 7 and 8. As the low melting point glass 7, 8, there may be used, for instance, those mainly comprising lead oxide and boron oxide; zinc oxide, lead oxide and boron oxide; lead oxide, boron oxide and thallium oxide; phosphoric acid and aluminum oxide; zinc oxide and boron oxide; and phosphorous pentaoxide, aluminum oxide and boron oxide. In the optical isolator according to the present invention, a low melting point glass is used for adhering the structural parts for the optical isolator, there is not observed any outgassing phenomenon due to the raise in ambient temperature as in the isolator which is assembled with an adhesive and the discrepancy of the optical axis due to the expansion of the adhesive.

Abstract: Apparatus for reading out information magneto-optically recorded in a magnetic layer comprises a single, polarization-preserving optical fiber for transmitting plane-polarized readout radiation from a source to the recording layer, as well as for transmitting such radiation, upon being reflected by the recording layer, toward a pair of photodetectors for the differential detection of the Kerr rotation angles (.+-..THETA..sub.k) produced by the up/down orientation of the vertically oriented magnetic domain in the recording layer. Optical feedback of the reflected readout radiation to the readout source is minimized by the provision of a pair of polarization beam-splitters having a 45 degree magneto-optic polarization-rotator (e.g. a Faraday rotator) positioned therebetween. The polarization beam-splitters and retardation plate are positioned in the optical path between the readout source and the optical fiber.

Abstract: An electron wave interference device controlled by a light is disclosed. The electron wave interference device includes a first channel to propagate an electron wave, a second channel arranged with an interval from the first channel for propagating an electron wave, and an magnetic field application device for applying a magnetic field into the first and second channels and a region sandwiched by those channels so as to traverse them. The electron waves which are respectively propagated in the first and second channels mutually interfere, and when the light is irradiated to those channels, a distance between peaks of wave functions of the electron waves which propagate in the channels is changed, so that a phase difference occurs in the electron waves.

Abstract: An optical isolator having three or four birefringent crystals and two magneto-optic elements is disposed between two light waveguides to prevent reverse-directed light from returning to the light waveguide on the light-source side. Forward-directed light emitted from the light waveguide on the light-source side is allowed to properly enter into the other light waveguide, whereas the reverse-directed light returning reflectively toward the light waveguide on the light-source side is separated into two polarized component and undergoes polarization rotation while propagating in the optical isolator, to thereby advance out of the optical axis of the light-source side light waveguide.

Abstract: Apparatus according to the invention comprises a magneto-optic isolator. The isolator comprises a magneto-optic member that comprises a single crystal substrate and a single crystal garnet layer on the substrate. The garnet layer comprises a first and a second stratum. The composition of the former is chosen such that the lattice constant of the first stratum material is substantially equal to that of the substrate at a first temperature (e.g., room temperature), and is substantially larger than that of the substrate at a second temperature (e.g., the garnet growth temperature) that is higher than the first temperature. The composition of the second stratum is chosen such that the lattice constant of the second stratum is less than that of the substrate at the first temperature, and is less than that of the first stratum at the second temperature. Wafers according to the invention typically are less subject to fracture than analogous prior art wafers.

Abstract: A non-mechanical optical switch is provided for alternately switching a monochromatic or quasi-monochromatic light beam along two optical paths. A polarizer polarizes light into a single, e.g., vertical component which is then rapidly modulated into vertical and horizontal components by a polarization modulator. A polarization beam splitter then reflects one of these components along one path and transmits the other along the second path. In the specific application of gas filter correlation radiometry, one path is directed through a vacuum cell and one path is directed through a gas correlation cell containing a desired gas. Reflecting mirrors cause these two paths to intersect at a second polarization beam splitter which reflects one component and transmits the other to recombine them into a polarization modulated beam which can be detected by an appropriate single sensor.

Abstract: An improvement in a method of rotating the plane of polarization of polarized light in a Faraday rotator, having an optical element which includes a ferromagnetic material, which comprises varying the strength of the magnetic field generated along the optical axis of the optical element in response to changes in the wavelength of the polarized light. The magnet employed in the Faraday rotator may be at least one permanent magnet or an electromagnet. Preferred optical elements are made of disc having a gadolinium-gallium-garnet (GGG) or large lattice constant (LLC) substrate, and the substrate is coated with an oxygen--and iron--containing film.

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.

Abstract: An optical light beam position control system utilizes Kerr cells and Lummer-Gehrcke plates to produce sets of optical phased linear arrays for beam positioning and beam monitoring. The system controls a light beam in the vertical and horizontal axes by the means of two optical phased linear array generators with associated monitoring and positioning optics.

Abstract: Optical shutters having a magneto-optical material confined in a holding plate which allows a light to pass through the magneto-optical material. When the intensity of a magnetic field applied to the magneto-optical material is changed, an amount of a polarized light passing through the magneto-optical material is adjusted. A magnetic head with a coil has open ends which are disposed to face the outer surface of a shutter member. A plurality of such optical shutters are arranged to form an optical shutter array.

Abstract: An optical fiber magnetometer having omnidirectional capability is disclo herein for measuring a total magnetic field independent of its physical orientation or the direction of the field or fields. A relatively long optical fiber defining a sensing arm for exposure to a magnetic field is wound in the form of a spheroid (like rubber bands on a golf ball or yarn threads on a baseball) to provide optical path lengths of substantially the same total length in every direction through the spheroid winding. The plane of polarization of light transmitted through the optical fiber winding is caused to rotate (Faraday effect) when the fiber or components thereof is exposed parallel to a magnetic field. The extent of plane rotation is determined, inter alia, by the total magnetic field passing through the spheroid winding.

Abstract: An optical isolator is disclosed which comprises a Faraday rotator disposed between a pair of polarization selective elements (e.g., linear polarizers, birefringent wedges, birefringent plates, etc.). Improvement in isolation stability as a function of variations in temperature and/or signal wavelength are achieved in accordance with the teachings of the present invention by utilizing a Faraday device with a rotation .theta. less than the conventional 45.degree.. A linear reduction in .theta., while resulting in a some signal loss, provides a linear increase in both temperature and wavelength stability.