Abstract: A magneto-optic modulator modulates signals from a superconducting circuit such as a single-flux-quantum (SFQ) logic system onto a carrier wave light beam. The modulator is formed by depositing a magneto-optic material such as EuSe onto a superconducting ground plane such as that of the circuit. A microwave microstrip line is formed on the magneto-optic material and carries a signal from the circuit. The signal induces an H field in the magneto-optic material which causes the magneto-optic material to modulate the light.

Abstract: The integrated magneto-optical modulator with optical isolator of the present invention comprises an optical isolator unit, a magneto-optical modulator unit, an impedance adjuster. The optical isolator unit rotates a polarization of an incident light from a light source to transmit the light with rotated polarization, and eliminates a reflected feedback light toward the light source. The magneto-optical modulator unit modulates an intensity of the light from the optical isolator unit and transmitting the modulated light outside. The impedance adjuster adjusts electrical impedance at the magneto-optical modulator unit in order to effectively introduce the high-frequency signal for light modulation to the magneto-optical modulator unit. Further, the optical isolator unit and the magneto-optical modulator unit are contained a single package.

Abstract: The magneto-optic modulator rotates a polarization of a light incident to a magneto-optic device which causes Faraday effect under such a magnetic field arrangement that the RF magnetic field has a component perpendicular to a light propagation direction and the RF magnetic field is directed to more than ±30° from the bias magnetic field direction. The bias magnetic field generator may be a permanent magnet, while the RF magnetic field generator may be a strip line running along a waveguide for the incident light. The strip line is fed by an RF electric current signal. The light beam is modulated at a frequency as high as about 10 GHz. The modulation depth can be further improved by using an impedance transformer and magnetic core.

Abstract: A liquid phase epitaxy method is used to grow the Faraday rotator with a small saturation field (Hs). The Faraday rotator has the formula: Bi3−x−y−zGdxTbyMzFe5 −w−nGawPnO12, where M is selected from Y, Yb,Lu, and P is selected from Al, Si, Ge. X, y, w and n are chosen from the ranges of 0.5≦x≦1.0, 0.5≦y≦1.0, 0.2≦z≦0.5, 1.5≦x+y+z≦2.0, 0.5≦w≦1.0, 0.15≦n≦0.5, 0.8≦w+n≦1.2. Without M and P, a Type-L Faraday rotator with a linear BH curve is provided, which is well suited for variable optical attenuators. With M and P, a Type-R Faraday rotator with a rectangular hysteresis loop is provided, which is well suited for optical switches. Both are also well suited for use in optical isolators and circulators.

Abstract: The present invention aims at providing a transmission wavelength characteristics variable optical element which can actively equalize changes of the wavelength characteristics due to temperature changes, and providing a wavelength characteristics variable apparatus, an optical amplifier, an optical transmission system, and a control method of the transmission wavelength characteristics, which use such an optical element.

Abstract: In a magneto-optical switching element with a Faraday rotator, in order to increase the switching speed and to reduce the required switching energy respectively, the rotator consists of a magnetically uniaxial crystal, which features magnetic domains of both signs in each of its stable states, by means of which problems are avoided with the creation of domains of opposite signs at the beginning of the switching process.

Abstract: A small-sized magnetic field generator which is suitable for mass production and provides better output stability. A plurality of coils are formed on a non-magnetic insulating material by depositing at least one layer of conductive film in a spiral pattern. A hollow is made in the center of each coil, so that a plurality of main magnetic cores are arranged on the insulating substrate, with their ends fit into those hollows. By supplying appropriate electrical signals to drive the coils individually, their combined magnetic field can be controlled to have an arbitrary distribution. This combined magnetic field is applied to a magneto-optical target device held on the insulating material.

Abstract: Miniature optical devices, including circulator array devices, are fabricated using thin film coating technology. A typical optical device according to the present invention includes two refraction elements arranged opposite each other along a propagation axis and coupled on opposite ends to first and second polarization orientation elements with first and second polarization beam splitter (PBS) elements are coupled to the first and second polarization orientation elements, respectively. The refraction elements include complementary Wollaston Prism elements or complementary Rochon Prism elements. Each polarization orientation element includes a Faraday rotator element, and in some embodiments, each also includes a half-wave plate formed using thin film coating techniques.

Abstract: An optical device includes a first birefringent crystal having a refractive index difference &Dgr;n1 and a length l1 and a second birefringent crystal having a refractive index difference &Dgr;n2 and a length l2. The first and second birefringent crystals are optically aligned and oriented so that a face of the first birefringent crystal and a face of the second birefringent crystal permit at least one optical beam to enter the face of the first birefringent crystal, pass through the first birefringent crystal, enter the face of the second birefringent crystal, and pass through the second birefringent crystal The face of the first birefringent crystal and the face of the second birefringent crystal are tilted relative to each other. The tilting adjusts at least the path length of optical beam through the first birefringent crystal, thereby permitting a precisely tuned frequency response without requiring corresponding precision in the length of the crystals.

Abstract: In all-optical networks, high speed optical switching and routing becomes one of the most important issues for interconnecting the transport network layers. This invention describes novel polarization-independent high speed optical switches using a digital Faraday rotator, which can also be used for various other optical switching devices. The basic digital Faraday rotator device is composed of (a) a semi-hard or hard iron garnet based magneto-optic crystal having bi-stable magnetization states at zero external magnetic field. (b) a wire winding around the crystal for changing the magnetization states by pulsed current having both fast rise time and short duration. (c) a circuit generating the required current pulses with both polarities.

Abstract: A hard magnetic Bi-substituted rare earth iron garnet material with excellent Faraday rotary moment, temperature property, wavelength property and insertion loss is provided. A Bi-substituted rare earth iron garnet material having a chemical composition of (Bi3−a−b−cGdaTbbYbc) Fe(5−w)MwO12 (where, M is at least one element selected from the group consisting of Ga, Al, Ge, Sc, In, Si and Ti, 0.5≦a+b+c≦2.5, 0.2≦w≦2.5) can be provided with hard magnetism and have excellent Faraday rotary moment, temperature property, wavelength property and insertion loss.

Abstract: A Faraday rotator is provided which obtains excellent optical characteristics with a small number of layers. In the Faraday rotator, a metal reflective film is formed on a substrate, then a first periodic dielectric multilayer film made of silicon dioxide SiO2 and tantalum pentaoxide Ta2O5, a magneto-optical thin film, and a second periodic dielectric multilayer film made of tantalum pentaoxide Ta2O5 and silicon dioxide SiO2 are formed sequentially. The number of layers of the first periodic dielectric multilayer film is larger than that of the second periodic dielectric multilayer film. Incident light from a polarizer passes through the periodic dielectric multilayer films, is reflected at the metal reflective film, returns through the periodic dielectric multilayer films, and passes through an analyzer to exit out.

Abstract: The present invention relates to the use of magnetic materials in combination with magneto-optic materials to improve performance of Faraday rotator devices by enhancing the latching capability and reducing the driving current. Semi-hard magnetic materials are advantageously used in connection with some embodiments of the present invention. Placing such semi-hard magnetic materials in proximity with the magneto-optic material enhances latching and reduces the drive current required to cause switching. Encompassing both the magneto-optic material and the semi-hard magnetic material further reduces drive current requirements and enhances latching by reducing leakage of the magnetic field from its generation within the coil to the magneto-optic material. Some embodiments further include soft or semi-hard material encompassing the coil.

Abstract: The present invention provides improved optical switches in which no mechanical movement is required to direct optical pathways between plural fiber ports and light transmission is bi-directional. Advantageously, the inventive switches permit bi-directional light transmission. The inventive switches also incorporate light bending devices to allow two fibers to be coupled to the light beams using a single lens for compactness. In the inventive switch, an optical signal is spatially split into two polarized beams by a birefringent element, which passes through a polarization rotation device that comprises waveplates, walk-off elements, and an electrically controllable polarization rotator, and recombine into an output fiber, achieving polarization independent operation. The switches of the present invention rely on electro-magnetically or electro-optically switching the beam polarizations from one state to another to rapidly direct the light path.

Abstract: A ferrule connection optical isolator with an optical fiber, wherein the optical isolator includes a ferrule with at least one processed end surface. The optical fiber consists of two kinds of materials and has a concentric level difference between the materials. A small cylindrical magnet having a size larger than the outer diameter of the level difference portion but smaller than the outermost diameter of the ferrule is connected to the level difference portion. A guide ring is inserted and fixed in the magnet, and an optical element that consists of at least one polarizer and at least one Faraday rotator is connected and fixed in the guide ring.

Abstract: A system of angular displacement control for micro mirrors includes a stationary vertical element, a stationary horizontal element and an interference eliminator. Alternatively, the stationary horizontal element holds micro mirrors in place during transportation for avoiding vibration and collision. The stationary vertical element orientates the micro mirrors in the vertical position. The interference eliminator eliminates magnetic interference that could affect the operation of the micro mirrors. The micro mirrors having interference eliminators are capable of remaining unaffected by operations of other micro mirrors.

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: The present invention provides a magneto-optical member capable of ensuring an excellent light transmittance and an optical isolator using the same. A first one-dimensional magnetic photonic crystal having a magneto-optical thin film, and a second one-dimensional magnetic photonic crystal having another magneto-optical thin film are laminated so as to sandwich a dielectric thin film with a small refractive index having an optical length of &lgr;/4+m&lgr;/2 where &lgr; is a wavelength of light and m is 0 or a positive integer. Since a plurality of magneto-optical thin films are present as magnetic thin films and hence the total thickness of the magnetic thin films is increased, the Faraday rotation angle is increased. Also, a large light transmittance can be obtained because of the presence of the dielectric thin film with a small refractive index having (&lgr;/4+m&lgr;/2) thickness where the first and second one-dimensional magnetic photonic crystals are laminated.

Abstract: An integrated micro-optical system includes at least two wafers with at least two optical elements provided on respective surfaces of the at least two wafers, at least one of the two optical elements being a spherical lens. The resulting optical system presents a high numerical aperture. One of the optical elements may be a refractive element formed in a material having a high index of refraction.

Abstract: An optical signal transmission system equipped with a magneto-optical modulator is provided. The magneto-optical modulator works to modulate an optical beam emitted from a light source and consists of a polarizer, a magneto-optical element, an analyzer, a dc field generator, a high-frequency field generator, and an impedance adjuster. The dc field generator works to apply a dc bias field to the magneto-optical element. The high-frequency generator is responsive to the high-frequency signal from said high-frequency signal generator to apply a high-frequency field to the magneto-optical element. The impedance adjuster works to adjust impedance of the high-frequency field generator for establishing effective transmission of the high-frequency signal to the high-frequency field generator, thereby increasing a modulation range up to frequencies higher than an upper limit of typical magneto-optical modulators.

Abstract: A torsional micro-mechanical mirror system includes a mirror assembly rotatably supported by a torsional mirror support assembly for rotational movement over and within a cavity in a base. The cavity is sized sufficiently to allow unimpeded rotation of the mirror assembly. The mirror assembly includes a support structure for supporting a reflective layer. The support structure is coplanar with and formed from the same wafer as the base. The torsional mirror support assembly includes at least one torsion spring formed of an electroplated metal. An actuator assembly is operative to apply a driving force to torsionally drive the torsional mirror support assembly, whereby torsional motion of the torsional mirror support assembly causes rotational motion of the mirror assembly. In another embodiment, a magnetic actuator assembly is provided to drive the mirror assembly.

Abstract: Integrated optoelectronic devices include a substrate having an opening therein that extends at least partially therethrough and a ledge extending inwardly from a sidewall of the opening. A pop-up mirror is provided in the opening. The mirror has an underside edge that is supported by an upward facing portion of the ledge when the mirror is in a closed position. A hinge is also provided. The hinge mechanically couples the mirror to the substrate so that the mirror can be rotated from the closed position to an open position.

Abstract: Described are the design of a rare earth iron garnet sensor element, optical methods of interrogating the sensor element, methods of coupling the optical sensor element to a waveguide, and an optical and electrical processing system for monitoring the polarization rotation of a linearly polarized wavefront undergoing external modulation due to magnetic field or electrical current fluctuation. The sensor element uses the Faraday effect, an intrinsic property of certain rare-earth iron garnet materials, to rotate the polarization state of light in the presence of a magnetic field. The sensor element may be coated with a thin-film mirror to effectively double the optical path length, providing twice the sensitivity for a given field strength or temperature change. A semiconductor sensor system using a rare earth iron garnet sensor element is described.

Abstract: A light wavelength converting element having a periodic polarization inversion structure is produced in the following manner: a comb-shaped electrode and a plate electrode are attached to both surfaces of an MgO—LN substrate, and the MgO—LN substrate is immersed in an insulating liquid. In a state in which substrate temperature is at room temperature, the plate electrode is grounded and a pulse voltage of +0.75 kV, for example, is applied for one second such that the comb-shaped electrode has positive potential. Then, the comb-shaped electrode is grounded and a pulse voltage of −3.25 kV, for example, is applied for ten seconds such that the plate electrode has negative potential.

Abstract: The present invention relates to the use of magnetic materials in combination with magneto-optic materials to improve performance of Faraday rotator devices by enhancing the latching capability and reducing the driving current. Semi-hard magnetic materials are advantageously used in connection with some embodiments of the present invention. Placing such semi-hard magnetic materials in proximity with the magneto-optic material enhances latching and reduces the drive current required to cause switching. Encompassing both the magneto-optic material and the semi-hard magnetic material further reduces drive current requirements and enhances latching by reducing leakage of the magnetic field from its generation within the coil to the magneto-optic material. Some embodiments further include soft or semi-hard material encompassing the coil.

Abstract: The present invention is directed to an optical assembly with a substrate. A non-latching optical component is attached to the substrate and includes a non-latching garnet and a permanent magnet in magnetic communication with the garnet. Also, a latching optical component is attached to the substrate and includes a latching garnet. A magnetic shield is between the non-latching optical component and the latching optical component.

Abstract: A beam shutter is provided which comprises a plane-parallel birefringent element for separation arranged to separate input light beams having orthogonal polarization directions on the same optical path; a plane-parallel birefringent element for synthesis arranged to synthesize light beams having orthogonal polarization directions on different optical paths, for output; the birefringent element for separation and the birefringent element for synthesis being disposed in a spaced apart relationship; and polarization rotating means having a variable Faraday rotator, the polarization rotating means interposed between the birefringent element for separation and the birefringent element for synthesis, for magneto-optically controlling the polarization directions; wherein transmission and interruption of output light beams are controlled by switching the polarization directions by means of the variable Faraday rotator.

Abstract: An optical isolator constituted by disposing optical elements comprising at least three polarizers and two faraday rotators with respect to a forward direction of light, wherein magnets, which are magnetized so that these magnetic poles are different from each other, are oppositely disposed by inserting the optical elements therebetween, the optical elements are constituted by disposing a first polarizer, a first faraday rotator, a second polarizer, a second faraday rotator and a third polarizer in order, the first and the third polarizers have the same transmission polarizing direction, and a faraday rotation direction of the first faraday rotator is different from that of the second faraday rotator toward a forward direction of light, and there is provided a reliable, productive and low cost multistage optical isolator having high backward loss and that both an incident and exit transmission polarizing directions are identical with each other.

Abstract: A system of angular displacement control for micro mirrors includes a stationary vertical element, a stationary horizontal element and an interference eliminator. Alternatively, the stationary horizontal element holds micro mirrors in place during transportation for avoiding vibration and collision. The stationary vertical element orientates the micro mirrors in the vertical position. The interference eliminator eliminates magnetic interference that could affect the operation of the micro mirrors. The micro mirrors having interference eliminators are capable of remaining unaffected by operations of other micro mirrors.

Abstract: An integrated micro-optical system includes at least two wafers with at least two optical elements provided on respective surfaces of the at least two wafers, at least one of the two optical elements being a spherical lens. The resulting optical system presents a high numerical aperture. One of the optical elements may be a refractive element formed in a material having a high index of refraction.

Abstract: A Faraday rotator and an optical attenuator using the Faraday rotator in which both a fixed magnetic field parallel to and a valuable magnetic field perpendicular to the optical axis are applied to Faraday elements, said optical axis being in the <111> direction of single crystal of garnet, characterized in that three single crystals of garnet of substantially the same thickness having the Faraday effect are used to form Faraday elements and the Faraday elements are arranged in such a manner that a variable magnetic field is applied to one of the Faraday elements, over a range extending 5 deg. each to the left and right of the line connecting the (111) plane in the center of the stereographic projection chart with the (−1−12) plane on the outermost circumference or a plane equivalent thereto in the chart, whereas a variable magnetic field is applied to the remaining two elements, over a range extending 5 deg.

Abstract: The invention relates to new single- or multi-metallic magnetic colloid particles (for example, Fe, Co, Ni, Fe/Co) having a size of up to 20 nm, the surface of which is protected against corrosion by precious metals, such as Pd, Ag, Pt or Au. The invention also relates to a method for producing such materials. In isolated form or in solution said materials are used among other things as sealing media against dust and gas in magnetic fluid seals (liquid O ring), for lubricating and mounting rotating shafts (magnetic levitation bearing), for the magnetooptic storage of information as well as for the magnetic marking of cells and their separation in biological samples or for the local administration of medicines.

Abstract: An optical filter having a changeable optical transmittance versus wavelength characteristic curve to variably filter a light. The curve maintains a fixed optical transmittance at a specific wavelength as the curve is changed. The optical filter includes a Faraday rotator having a variable Faraday rotation angle, to change the optical transmittance versus wavelength characteristic curve.

Abstract: The present invention relates to optical switches in which switching occurs by changing the rotation of the plane of polarization by means of an externally applied control signal, particularly to magneto-optical switches controlling the port by which light emerges from the switch by externally-applied magnetic fields. The switches of the present invention function for randomly polarized input light, producing similarly randomly polarized light at the appropriate output port. Specific embodiments relate to 1×2 and 1×4 switches in both single pass and dual pass embodiments. Single pass embodiments are switches in which light passes through the optical components in one direction emerging at the appropriate output port depending on the desired switching. Dual pass embodiments are switches in which the light makes a forward and reverse traverse of the switch with total reflection. Dual pass switches typically reduce crosstalk without increasing the size of the switch.

Abstract: This invention provides polarization independent magnetooptic switches. Input optical signals are switched to different output ports via polarization manipulation utilizing magnetically switchable Faraday rotators, polarization beam splitters (PBS) and polarization beam combiners (PBC). The Faraday rotators are Bi-substituted magnetic garnet with small coercivity, and PBS/PBC made from birefringence crystals. The switching Faraday rotator is mounted inside a soft magnetic ferrite core, which is magnetized by an electric coil outside. To ensure a high switching speed, the selected ferrite core exhibits high frequency characteristic. Based on the same principle of polarization manipulation, a latching magnetooptic switch (only a current pulse is required) can be built using a latchable Faraday rotator as a switching control unit.

Abstract: An integrated micro-optical system includes at least two wafers with at least two optical elements provided on respective surfaces of the at least two wafers. An active element having a characteristic which changes in response to an applied field may be integrated on a bottom surface of the wafers. The resulting optical system may present a high numerical aperture. Preferably, one of the optical elements is a refractive element formed in a material having a high index of refraction.

Abstract: An optical isolator comprsing at least two parts of a Faraday rotator obtained from a garnet crystal and an analyzer, which is small in size, can be mounted directly to a semiconductor laser. The garnet crystal is grown, by a liquid-phase epitaxial growth technique, on the substrate of a garnet with a lattice constant of 12.514±0.015 Å, and consists of the following composition formula: (Tb1−(a+b+c+d)LnaBibM1cEud)3(Fe1−eM2e)5O12 where Ln is an element selected from rare-earth elements excluding Tb and Eu, and Y; M1 is an element selected from elements Ca, Mg, and Sr; M2 is an element selected from elements of Al, Ga, Sc, In, Ti, Si, and Ge; a, b, c, d, and e are defined as 0≦a≦0.5, 0.3<b≦0.6, 0≦c≦0.02, 0<d≦0.3, and 0.01<e≦0.3, respectively.

Abstract: A short pulse of radiation is generated by shining radiation through a magneto-optical material. The material is excited twice to rapidly change a property of the wave, such as the direction of the polarization. The first excitation rotates the polarization in a first direction and the second excitation brings the polarization back to its initial direction before the first excitation. Although the time for relaxation from the excitations may be lengthy, a pulse of light can be produced that is shorter in time than the time for excitation plus the time for relaxation. Light experiencing the pair of lengthy relaxations has each cancelling the effect of the other. The pulse of light has a length that depends on the time difference between the two excitations and the spacing between them. The rapid excitations are provided by pulses of current in a superconductor located near the magneto-optical material.

Abstract: A reflection type Faraday rotator includes first to sixth reflection type sub-rotators. Light is made incident on the first to sixth sub-rotators while repeating reflecting thereat. A Faraday rotation occurs at a sub-rotator having a center wavelength equal to the wavelength of the light The sub-rotators are of reflection-type, have a larger bandwidth of outgoing light compared to a transmission type, and have center wavelengths (wavelength characteristics) different from one another. Thus, the effective wavelength range (the wavelength bandwidth) is increased. Expensive optical devices conventionally required for increasing the wavelength bandwidth are not needed. Accordingly, the cost can be reduced.

Abstract: A short pulse of radiation is generated by shining radiation through a magneto-optical material. The material is excited twice to rapidly change a property of the wave, such as the direction of the polarization. The first excitation rotates the polarization in a first direction and the second excitation brings the polarization back to its initial direction before the first excitation. Although the time for relaxation from the excitations may be lengthy, a pulse of light can be produced that is shorter in time than the time for excitation plus the time for relaxation. Light experiencing the pair of lengthy relaxations has each cancelling the effect of the other. The pulse of light has a length that depends on the time difference between the two excitations and the spacing between them. The rapid excitations are provided by pulses of current in a superconductor located near the magneto-optical material.

Abstract: A Faraday rotator is provided which obtains excellent optical characteristics with a small number of layers. In the Faraday rotator, a metal reflective film is formed on a substrate, then a first periodic dielectric multilayer film made of silicon dioxide SiO2 and tantalum pentaoxide Ta2O5, a magneto-optical thin film, and a second periodic dielectric multilayer film made of tantalum pentaoxide Ta2O5 and silicon dioxide SiO2 are formed sequentially. The number of layers of the first periodic dielectric multilayer film is larger than that of the second periodic dielectric multilayer film. Incident light from a polarizer passes through the periodic dielectric multilayer films, is reflected at the metal reflective film, returns through the periodic dielectric multilayer films, and passes through an analyzer to exit out.

Abstract: A Faraday rotator of multilayer film type is provided in which satisfactory optical characteristics are obtained with a small number of layers. In the Faraday rotator, a first periodic dielectric multilayer film made of silicon dioxide SiO2 and tantalum pentaoxide Ta2O5 is formed on a substrate, then a magneto-optical thin film, and a second periodic dielectric multilayer film made of tantalum pentaoxide Ta2O5 and silicon dioxide SiO2 are formed sequentially. The first and second periodic dielectric multilayer films sandwich the magneto-optical thin film such that their respective higher refractive dielectric thin films are in contact with the magneto-optical thin film. The number of layers of the first periodic dielectric multilayer film is larger than that of the second periodic dielectric multilayer film.

Abstract: An optical modulator includes a magnetic ferrite single crystal, an optical source, a photoreceptor system and an analyzer. The magnetic ferrite single crystal has a transducer mounted and arranged to receive a microwave. The microwave is modulated by a signal having a frequency lower than the microwave. Light emitted from the optical source is introduced to the magnetic garnet single crystal and modulated by the microwave applied to the transducer. The photoreceptor system receives the modulated light that is emitted from the magnetic ferrite single crystal. The analyzer is provided between the magnetic ferrite single crystal and the photoreceptor system, and the analyzer is arranged such that a rotation angle of the analyzer about an optical axis thereof is shifted by an angle in the range of about 40 degrees to about 50 degrees from an extinct position at which an amount of direct-current light transmitted through analyzer is minimized.

Abstract: A low-rate data transmission system and method are disclosed that use the Faraday effect to modulate the polarization state of light traveling in an optical fiber. The resulting change in polarization is used to communicate information over the fiber. The low-rate data transmission system includes a low-rate signal source producing current in a wire coil wrapped around an optical fiber. Information is conveyed in accordance with the present invention by the selectively introducing a polarization change into the light carried by the fiber. Generally, the source light at the input of the optical fiber can be randomly polarized and information is conveyed in accordance with the present invention by the presence or absence of a predefined polarization introduced into the light. The longitudinal magnetic field produced by a current in the coil rotates the plane of polarization of the light, in accordance with the well-known Faraday effect.

Abstract: A lens arrangement is proposed for the particle-optical imaging of an object (23), to be imaged and positionable in an object plane (27), into an image area (31), comprising

Abstract: A short intense pulse of radiation is generated by shining radiation through a magneto-optical material and providing multiple stimulations to the material. The material is excited multiple times to rapidly change a property of the radiation, such as the angle of its polarization. The first excitation rotates the polarization in a first direction and the second excitation can rotate the polarization further. Alternatively the second excitation can bring the polarization back to its initial direction. Effect of lengthy relaxation times in the material cancel each other out and the pulse of light has a length that depends on the time difference between the two excitations and the spacing between them. This allows a pulse of light to be produced that has more rotation or has a shorter pulse width than the time for excitation plus the time for normal relaxation of the magneto-optical material.

Abstract: An optical attenuator using an isolator, and an optical communications system including the same, function to control the intensity of an input optical signal. The isolator comprises a Faraday rotator in which a rotation angle of polarization varies depending on the intensity of an applied magnetic field. As a result, the level of isolation of an optical signal changes in accordance with the rotation angle of polarization and an attenuated optical signal is outputted. A magnetic field generator generates a magnetic field having an intensity which is controlled by the intensity of current, and the generated magnetic field is applied to the isolator A power supply supplies current to the magnetic field generator and controls the intensity of the current. A magnetic core and a coil are installed on the optical isolator, and currents applied to the coil are controlled to adjust the intensity of the magnetic field which is formed on the isolator.

Abstract: A smart magnetometer which includes at least one cantilevered magnetostrictive/optical fiber structural bonded composite in a vibrationally isolated housing allowing an optical signal to be transmitted and detected from one optical fiber to another such that fluctuations of the surrounding magnetic field H will cause fluctuating mechanical torque on the composite magnetostrictive beam which will be applied to the bonded cantilevered optical fiber to deflect or misalign and cause modulation of the optical signal transmitted between the two fibers. This modulation can be calibrated to the dynamic variation of strength of a neighboring magnetic field to a precision and sensitivity of less than 1 fT and 1 fT/sqrtHz. The system is smart to selectively filter out any neighboring magnetic field with average strength smaller or greater than a certain critical value.

Abstract: Optical isolators for use in fiber optic networks utilizing a birefringent wedge set with a Faraday rotator disposed between the birefringent wedges. In a first embodiment a polarization maintaining optical isolator is disclosed which will maintain the polarization of the light which passes through it in a forward direction and block light in the reverse direction. In a second embodiment a single polarization optical isolator is disclosed which will pass only a single linear polarization of the light in a forward direction and block any light in the reverse direction.

Abstract: A method for retrofitting a window by combining the window with a switchable or non-switchable window enhancement. The method includes providing a window comprising at least one relatively transparent viewing pane with first and second opposed viewing surfaces, and optionally a frame portion adapted to support and position the viewing pane(s); providing at least one mounting means adapted for securing the enhancement to the window; and securing a window enhancement to the window with at least one mounting means so that the enhancement overlies at least a portion of the viewing pane, and wherein a gap is produced between the window and the enhancement equal in width to the thickness of the mounting means. The enhancement may be mounted on either the viewing pane itself, or alternately upon the frame portion of the window. If desired, the enhancement may be laminated to a relatively rigid substrate prior to application to the window.