Abstract: The present invention relates to optical switches in which switching occurs by changing the rotation of the plane of polarization by application 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: A technique for improving optical cross-connections comprises placing a switch in front of a number of processing units. So configured, the units are no longer dedicated to a specific link or signal. When necessary, a unit is connected/disconnected to one or more optical links by the switch to carry out any number of processing functions, such as regeneration, Raman pumping, dispersion equalization/compensation or performance monitoring. Because the units are no longer dedicated to specific links the cost of the cross-connections and the network it is a part of can be reduced.

Abstract: The present invention includes a polarization independent optical interconnect device for selectively interconnecting a plurality of optical signals between a plurality of inputs and a plurality of outputs. The present invention may provide advantages typically associated with conventional polarization based switches, including terabit per second data rates and high speed switching, to facilitate use in fiber optic networks. Moreover, the switch of this invention is polarization independent, and therefore, may route either polarized or unpolarized light. Since both the input and output light may be unpolarized, the switch of this invention may have a high light efficiency (i.e. no losses associated with an input polarizer) and minimal insertion losses as compared to typical polarization based switches.

Abstract: A reset driving scheme for adressing a switching mirror display (20) enables current to flow in two directions through the switching elements (30). The display is forced into a predefined state and drives the display into the other optical states by using an adressable TFT (31) providing a continous current. A circuit that fulfils these requirements is indicated.

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.

Abstract: An optical switch (26) comprises an input switching element (12) having a plurality of light input ports (10) and an output switching element (16) having a plurality of light output ports (14). The input switching element (12) comprises a plurality of input optical deflector sets (20), each set consisting of a plurality of optical deflectors (18a, 18b), at each light input port (10). The input optical deflectors in each set are arranged in the incident direction of an optical signal that is input to one of the light input ports. The output switching element (16) comprises a plurality of output optical deflector sets (24), each set consisting of a plurality of optical deflectors (22a, 22b), at each light output port (14). The output optical deflectors in each set are arranged in the emergent direction of an optical signal that is output from one of the light output ports.

Abstract: A light modulating switch (210) including a switching element (218) having a first portion (226) of electro-optic material to which first and second electrodes (213, 224) are associated. A second portion (228) is composed of material having an index of refraction matching that of the first portion (226) when no voltage is applied to electro-optically activate the first portion (226), but the index of refraction of the second portion (228) is less than the index of refraction of the first portion (226) when the first portion (226) is electro-optically activated by application of voltage to the electrodes (213, 224).

Abstract: The present invention pertains to an optical shutter comprising an photon-absorbing layer and a surface layer in a transparent state on at least one side of the photon-absorbing layer, wherein the optical shutter is characterized by the absorption of photons to change the photon-absorbing layer to an opaque state and to change the surface layer to a reflective state. The optical shutter is reversibly imageable between these transparent and reflective states. The optical shutter may comprise a metallized layer on at least one side of the photon-absorbing layer. Preferably, the optical shutter comprises an organic free radical compound, such as a salt of an aminium radical cation, in the photon-absorbing layer. Also provided are optical switch devices and optical buffers comprising such optical shutters and methods of switching an optical signal utilizing such optical shutters and switch devices.

Abstract: Dual Pockels cell containing: a bar (112) in electro-birefractive material having a first (122) and a second (124) end, a first and a second ring electrode (126, 128) deposited at the ends of the bar, and a third electrode (127) formed on the bar between the first and second electrodes. Application to the fabrication of modulators or electro-optical switches.

Abstract: A light modulation element which has a transparent substrate 111 transparent for modulated light, a moving grid 114 comprising a plurality of slits 113 formed by arranging a plurality of grid plates 112 each having a shield property and spaced from each other, the moving grid 114 having at least a part having electrical conductivity, elastic support members for placing the moving grid 114 with a predetermined spacing on the transparent substrate 111 and supporting the moving grid 114 movably in an arrangement direction of the grid plates 112, shield films 119 formed at the positions of the transparent substrate 111 overlapping the slit positions of the moving grid 114, and moving grid move means for moving the moving grid 114 in the arrangement direction of the grid plates 112 by an electrostatic force generated by applying predetermined drive voltages to fixed electrodes placed on the transparent substrate 111 and the moving grid 114.

Abstract: The present invention,is directed to an optical space switch accommodating a plurality of input light paths and output light paths. The optical space switch comprises a plurality of polarization control optical switches, each consisting essentially of: polarization control means having elements, one for each input light path, for rotating through 90° the polarizing direction of light information incident from each input light path or otherwise retaining the polarizing direction thereof for output; and a light path routing element for routing the light path for the light information output from the polarization control means in accordance with the polarizing direction of the light information. These polarization control optical switches are arranged in a matrix pattern or coupled in cascade to implement a polarization control optical space switch.

Abstract: The present invention includes optical interconnection devices and optical interconnection systems. The invention also includes machines and instruments using those aspects of the invention. The invention may also be used to upgrade, repair, or retrofit existing machines or instruments, using methods and components known in the art. An optical interconnection device of the present invention utilizes a multiple-pass optical cell. This approach differs from previous approaches in that spatial light modulators are used in a White cell device or other multiple-pass optical configuration. In a spatial light modulator, each individual element typically only has two or three variations used to direct the light. Therefore, precise calibration is not needed. The light simply needs to be directed towards the appropriate arm of the optical cell, which utilizes a self-correcting mirror in order to direct a light stream to the next desired location in the system.

Abstract: Disclosed is a display device comprising a light-shielding plate including a metal thin film formed on a first principal surface of an optical waveguide plate for introducing the light thereinto and including light-transmitting sections formed at portions corresponding to picture elements to make penetration through the optical waveguide plate, and shutter sections provided opposingly to a second principal surface of the light-shielding plate, for selectively intercepting the light transmitted through the light-transmitting sections in accordance with an input signal. The shutter sections include actuator elements provided corresponding to the large number of light-transmitting sections so that the light to be transmitted through the light-transmitting sections is intercepted substantially in synchronization with the operation of the actuator elements. Accordingly, it is possible to improve the contrast and improve the image quality of a displayed image.

Abstract: An optical switch for switching an optical path of an input optical signal comprises a substrate composed of a silica glass substrate, a separation layer formed on the silica glass substrate, a plurality of cantilever beams and formed in parallel to one another on the separation layer and connected at their tip ends to a connection member, at least one silica glass optical waveguide core formed on the cantilever beams, a plurality of optical waveguide fixed in opposition to the silica glass optical waveguide core, a cover for covering the cantilever beams, and a switch drive unit for bending the cantilever beams. The switch drive unit comprises electromagnetic actuators, which comprise soft magnetic bodies formed on the connection member for the cantilever beams and on the substrate, soft magnetic yokes formed of a soft magnetic body, permanent magnets, and wire coils.

Abstract: The invention provides an optical switching method and apparatus by which the response time of a variation in refractive index of light can be further reduced. An electric field applied to a light passing element made of a substance containing conjugated system electrons is controlled to vary the condition of electrons of the substance of the light passing element to vary the refractive index of the light passing element. Then, the outgoing direction of light introduced into the light passing element is controlled to deflect the outgoing light from the light passing element, and the deflected outgoing light is introduced so as to be irradiated upon a selected control object element to control the control object element.

Abstract: Optically generated charge carriers in an optically responsive medium, such as an optical switch, which are produced in response to a first pulse of optical radiation (P1), are de-excited by directing a second pulse (P2) of optical radiation into the medium. The second pulse occurs while the excitation produced by the first pulse remains coherent, and the relative phase of the first and second pulses is selected so that the second pulse destructively interferes with the excitation produced by the first pulse. The apparatus may be used as an optical switch or as a photodetector.

Abstract: A light modulating device, such as a ferroelectric liquid crystal display (FLCD) comprises an addressable matrix and modulating elements or pixels and associated circuitry for selectively addressing each element in a series of addressing frames in order to vary the transmission level of each element relative to the transmissions levels of the other elements. Such addressing utilises a temporal dither addressing scheme for addressing at least part of each element within each frame with different combinations of temporal dither signals applied to separately addressable temporal bits within the frame to produce different transmission levels. In order to enable a large number of grey levels to be produced whilst limiting the perceived errors at transitions between different grey levels, the temporal bits are addressed in a first order in a first frame (or in a first spatial location) and in a second order, which is different to the first order, in a second frame (or in a second spatial location).

Abstract: The present invention is directed to an optical space switch accommodating a plurality of input light paths and output light paths. The optical space switch comprises a plurality of polarization control optical switches, each consisting essentially of: polarization control means having elements, one for each input light path, for rotating through 90.degree. the polarizing direction of light information incident from each input light path or otherwise retaining the polarizing direction thereof for output; and a light path routing element for routing the light path for the light information output from the polarization control means in accordance with the polarizing direction of the light information. These polarization control optical switches are arranged in a matrix pattern or coupled in cascade to implement a polarization control optical space switch.

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: An optical modulator controllably attenuates an optical signal by changing the index of refraction of an electro-optic prism in the modulator by varying the electrical bias applied to the electro-optic prism. Changing the index of refraction alters the path along which the optical signal travels through the optical modulator. By appropriately focusing the optical signal, the location of the optical signal relative to an output fiber can be controlled to vary the degree of optical coupling between the optical signal and the output fiber, thereby changing the amplitude of the outgoing optical signal. In one embodiment, the optical modulator has an electro-optic prism located between a lens and a mirror, where the mirror reflects the optical signal to pass through the prism and the lens two times: once along an input path and once along an output path.

Abstract: An optical multipath switch with electrically switchable photonic crystals.The invention involves the construction of optical multipath switches based on electrically switchable photonic crystals.A filled photonic crystal, switchable electrically and/or by light, is used as a tunable mirror. By creating selective optical deformations in the photonic crystal, its properties can be influenced in selected areas in terms of transmission capability. This is done preferably by application of a strong electrical field. Light is coupled in and out via fixed photonic mirrors located at an angle to the photonic crystal.The optical switches of the invention find application in switching networks and serve the purpose of service selection. A very high packing density may be achieved.

Abstract: The recording of an image is performed on a heat-mode sensitive material by an optical modulator equipped with an optical modulation element consisting of an electro-optic crystal substrate. An optical modulation element 10 has an electro-optic crystal substrate 11 consisting of PLZT ceramic. The optical modulation element 10 is arranged on a base plate 18 consisting of aluminum (Al). The base plate 18 is arranged on cooling mechanism 20 that cools the electro-optic crystal substrate 11. Temperature detection mechanism 23 for detecting the temperature of the electro-optic crystal substrate 11 is provided in a portion of the base plate 18. Control mechanism is provided for controlling the cooling mechanism 20 so that the temperature of the electro-optic crystal substrate 11 becomes constant, based on temperature information from the temperature detection mechanism 23.

Abstract: Optical modulators and switches for use in telecommunications systems are disclosed having solid-state crystalline optical material comprised of III-V, II-VI, and IV semiconductor nanocrystals embedded in a polymer matrix. In a preferred embodiment, the crystalline material comprises CdSe crystals sized at less than 5.8 nm in diameter and more preferably at less than about 4 nm in diameter and advantageously embedded in poly(vinyl pyridine). The crystalline material sandwiched between two electrodes defines an optical modulator. In one preferred embodiment, the crystalline material with ten-percent crystal embedded in a polymer will exhibit with an applied voltage of 100V, a differential absorbance spectra (.DELTA.A) of about 50 cm.sup.-1 at wavelengths of about 610 nm and a differential refractive index (.DELTA.n) of about 10.sup.-4 at wavelengths of about 625 nm.

Abstract: A method and apparatus for facilitating controllable switching an interface between a reflective state in which light incident upon the interface undergoes total internal reflection, and a non-reflective state in which total internal reflection is prevented at the interface. The apparatus incorporates a member (preferably an elastomer) which is deformable with respect to the interface. The member's Young's Modulus in portions of the member adjacent the interface is substantially greater (i.e. stiffer) than the member's Young's Modulus in portions of the member away from the interface. The stiffened portion of the member adjacent the interface may be in the form of a microstructure. A pair of electrodes coupled to a voltage source can be provided to controllably deform the member into optical contact with the interface, within a continuously variable range of optical contact values, to produce the non-reflective state in selectably varying degrees.

Abstract: A spatial light modulator for use in a optical printer where the spatial light modulator includes a plurality of cells, having a shape that is defined to decrease artifacts in an image produced on a recording medium by the optical printer. The shape of the plurality of cells merges a portion of the optical radiation passing through an individual cell of the spatial light modulator with optical radiation from that of adjacent cell to form a pixel on the recording medium. In one implementation each of the cells of the spatial light modulator independently modulate the optical radiation so as to print horizontally-displaced pixels. When LEDs are used as the colored light source, the light is either first diffused to minimize shadows from electrical contacts on the LEDs, thus removing linear artifacts in the image.

Abstract: Optical variable delay devices for providing variable true time delay to multiple optical beams simultaneously. A ladder-structured variable delay device comprises multiple basic building blocks stacked on top of each other resembling a ladder. Each basic building block has two polarization beamsplitters and a polarization rotator array arranged to form a trihedron; Controlling an array element of the polarization rotator array causes a beam passing through the array element either going up to a basic building block above it or reflect back towards a block below it. The beams going higher on the "ladder" experience longer optical path delay. An index-switched optical variable delay device comprises of many birefringent crystal segments connected with one another, with a polarization rotator array sandwiched between any two adjacent crystal segments.

Abstract: A spatial light modulator has a modulating region which is capable of operating in two modes in the first clear mode, the region is continuously and substantially uniformly transmissive. In a second or barrier mode, the region can be switched to form parallax barrier comprising slits which are separated by continuous opaque regions. Such A modulator may be used in association with an image liquid crystal display to provide an autostereoscopic 3D display having a 3D mode which may track movement of an observer and a 2D mode in which full resolution of the LCD is used.

Abstract: An optical power regulator employs a variable optical attenuator having a first birefringent element that spatially separates the input optical beam into two orthogonally-polarized beams. Both beams pass through a polarization modulator (e.g., a liquid crystal material) that rotates their polarizations to an extent determined by the control voltage applied across the polarization modulator. A final birefringent element spatially separates both beams exiting the polarization modulator into two pairs of orthogonally-polarized beams (i.e., two horizontally-polarized and two vertically-polarized components). The thicknesses and optical properties of the birefringent elements are selected so that two of the four beams are combined by the final birefringent element to exit at the output port of the regulator, while the remaining two beams are blocked.

Abstract: A split reciprocal polarization switch (SRPS) for use in constructing high performance switching devices used in fiber optics. The SRPS allows selective changes in the polarization of one or the other of two optical rays passing therethrough along first and second bi-directional ray paths of the SRPS so that they emerge therefrom with the same polarizations. The SRPS includes a switching section for selectively changing the optical polarization of optical rays according to a selected state of the switching section, and a split section including a first and second sections having different polarization changing characteristics.

Abstract: An optical shutter element drive mechanism for driving optical shutter elements that are electrically equivalent to condensers by charging and discharging the elements by a power source and switching elements. The optical shutter element drive mechanism includes a resistor through which a current for charging the optical shutter elements flows when the optical shutter elements are charged and through which a current for discharging the optical shutter elements flows when the optical shutter elements are discharged.

Abstract: An optomechanical sensor for measuring or detecting an acceleration or a vibration in at least one direction. The sensor has a frame, and a flexible beam having two ends. A first end is attached to the frame and a second end is mobile in the at least one direction, in response to an acceleration movement of the frame. The flexible beam includes an optical guiding structure having an input and an output. The frame has N light collection elements, where N is an integer .gtoreq.2. The frame also includes a multi-mode coupler having an input facing the output of the optical guiding structure and N outputs, the coupler coupling an optical signal at the output of the optical guiding structure to the N light collection elements. The multi-mode coupler may also transform an input light beam having a maximum into a distribution having N maxima at the output of the coupler.

Abstract: A switchable optical birefringent filter for polarized light incident thereon includes first and second retarder networks in optical series and a switch associated with at least one of the first and second retarder networks for selectively altering one of the polarization state and the angular orientation of the polarization state relative to the angular orientation of the second network, of light as it is received by the second network. In one operating mode, the filter produces a spectral filtration of light passing through the filter and in another mode transmits all light within a specified range of wavelengths without significant alteration.

Abstract: Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses.

Abstract: An optical switch is formed by: at least one switch driving circuit for generating ultrasonic waves; at least one electric acousto-optic element forming at least one diffraction grating therein upon being applied with the ultrasonic waves generated by the switch driving circuit; at least one polarization rotator for rotating a polarization plane of a first primary diffracted light produced by the diffraction grating, by 90.degree.

Abstract: The present invention is in the field of optical components, more particularly, polymeric optical components, even more particularly, thermo-optical components, electro-optical components or passive components. The present invention pertains to an optical component having an at least penta-layered polymer structure on a substrate comprising:A) a low refractive index lower cladding layer,B) a core-matching refractive index lower cladding layer,C) a core layer,D) a core-matching refractive index upper cladding layer, andE) a low refractive index upper cladding layer.With this specific layer structure an optimum traversal confinement can be obtained, which results in less loss of light and an improved switching efficiency.

Abstract: An integrated digital light modulator. In one embodiment, a light beam is split into a set of binary weighted beams which are then individually switched on or off by an optical switch. The weighted beams which are conveyed by the optical switches are then recombined to produce a modulated beam. In this manner, a fast inexpensive integrated digital light modulator may be advantageously obtained. Broadly speaking, the present invention contemplates a digital optical power modulator that comprises a binary power divider and an optical modulator. The binary power divider is configured to receive an input light beam and split it into a set of weighted beams. The optical powers of the weighted beams are related in that the ratio of the optical powers of any two weighted beams is substantially an integer power of two. The optical modulator receives the set of weighted beams from the binary power divider and receives a digital signal.

Abstract: An optical cross bar switch assembly includes a first lens device (5) in the form of an array of lenslets (5a) operable to receive light from the input optical fiber array (1) in a manner such that the light from each fiber is received and collimated separately by an associated one of the lenslets (5a) with the collimated light from the array (5) being passed to a fan out grating element (3) which angularly diffracts and replicates the light from the input optical fibers.

Abstract: A method and apparatus for modulating light, wherein a light source provides light of a certain wavelength to be modulated by a layer of superconducting material which forms part of a specifically configured plate assembly. The superconducting layer is placed in the optical path of the light source. Further the superconducting layer is switched between a partially transparent non-superconducting state and a substantially non-transparent superconducting state by a modulation circuit. The resulting optical pulses transmitted through the superconducting layer are converted from the original wavelength to a lower wavelength by a frequency converting device.

Abstract: A switchable lens includes first and second optically transparent substrates, a first electrically conductive, optically transparent contact film positioned on a surface of the first optically transparent substrate, a second electrically conductive, optically transparent contact film positioned on a surface of the second optically transparent substrate, and phase modulating material sandwiched between the first and second electrically conductive, optically transparent contact films. The phase modulating material has a lens function stored therein which is temporarily erasable by a potential applied between the first and second electrically conductive, optically transparent contact films, the phase modulating material thereby being capable of modulating light passing therethrough.

Abstract: A compound having nonlinear optical properties of the general formula:Ar.sup.1 CR.sup.1 .dbd.CR.sup.2 (Ar.sup.2 CR.sup.3 .dbd.CR.sup.4).sub.n Ar.sup.3 (I)wherein, n represents a whole number; R.sup.1, R.sup.1, R.sup.3 and R.sup.4 groups are independently selected from H, branched aliphatic, straight chain aliphatic, branched silane or straight chain silane; Ar.sup.1 and Ar.sup.3 are aromatic radicals having a substituent in at least one position adjacent to a site of attachment of the C.dbd.C double bond and having at least one electron withdrawing or electron donating substituent in at least one of the remaining positions; Ar.sup.2 is an aromatic radical having a substituent in at least one position adjacent to a site of attachment of the C.dbd.C double bond; with the proviso that the substituent in at least one position adjacent to the site of attachment of the C.dbd.C double bond and R.sup.1, R.sup.2, R.sup.3 and R.sup.4 groups are sufficiently large to cause Ar.sup.1, Ar.sup.2 and Ar.sup.

Abstract: Generally and in one form of the invention this is a periodic surface filter comprising at least one element at a surface of the filter and electronic controls to change the optical characteristics of the element. Other methods and devices are disclosed.

Abstract: Optomechanical device comprising in an integrated optics guiding structure, a fixed part and a mobile part, which is connected to the fixed part, said mobile part being located between i output microguides formed in the fixed part and j input microguides also formed in the fixed part, characterized in that the mobile part comprises a mass, which is only connected by fixing arms to the fixed part, so as to permit the displacement of the mass in a first direction, said mass having k microguides to permit the switching of a light beam from one of the j input microguides to one of the i output microguides.

Abstract: A system for optically providing one-to-many irregular interconnections, and strength-adjustable many-to-many irregular interconnections which may be provided with strengths (weights) w.sub.ij using multiple laser beams which address multiple holograms and means for combining the beams modified by the holograms to form multiple interconnections, such as a cross-bar switching network. The optical means for interconnection is based on entering a series of complex computer-generated holograms on an electrically addressed spatial light modulator for real-time reconfigurations, thus providing flexibility for interconnection networks for large-scale practical use. By employing multiple sources and holograms, the number of interconnection patterns achieved is increased greatly.

Abstract: A programmable optical filter and an optical circuit arrangement using the filter has an optical demultiplexer for a spatial separation of the wavelengths from one another and a control arrangement composed of either an optical absorption modulator or an optical switch for controlled influencing of the light of the wavelength independent of other wavelengths. An optical amplifier may be arranged with each of the optical switches or absorption modulators.

Abstract: A variable spectral resolution agile filter has instantly adjustable spectral resolution with no required mechanical motion and a quickly adjustable center wavelength. Adjustment of the center wavelength is accomplished by reliable piezoelectric actuators. Adjustment of the spectral resolution is achieved by changing the finesse of the system, the finesse being governed by the reflectivity of the faces. By making one of the faces exhibit electrically variable reflectivity, the finesse of the system is instantly changeable, and thus the spectral resolution is also instantly changeable.

Abstract: An interferometric optical switching device for switching substantially coherent light beams includes a plurality of interferometric switching cells arranged in matrix form. Each interferometric switching cell is independently controllable to selectively direct received light beams along at least a selected one of two axes. The device can be three-dimensionally expanded to increase the number of ports to which the light beams can be selectively switched, in which case the matrices can share integrally constructed interferometric switching cells. The device is further capable of providing bidirectional communication between predetermined ones of the ports thereof.

Abstract: In a bistable switching display device the occurrence of artefacts due to considerable changes of periodicity between successive grey scale stages is reduced by a suitable subdivision of the electrodes (112). To this end a drive unit (116) allocates fewer than 2.sup.n grey scale stages to each pixel (113) which is subdivided into n sub-pixels (113.sup.a, 113.sup.b, 113.sup.c). The change of periodicity will decrease when a suitable division of the surface ratios and drive sequence are chosen.

Abstract: An optical switch has a substrate and a transparent material in which a three-dimensional diffraction pattern is recorded which is capable of diffracting light, the material having non-linear optical properties and extending in the form of a first layer above the substrate. At least one first electrode and at least one second electrode are provided for varying the diffraction pattern in accordance with applied voltages.

Abstract: An electric field absorption light modulation unit includes a light emission device for emitting light and a modulation device for varying a light transmittance thereof of light applied by the light emission device so as to provide the light as a result of modifying thereof. A driving signal generating unit coupled with the electric field absorption light modulation unit generates a driving signal to be applied to the modulation device from an input information signal by making the modulation device vary the light transmittance thereof, and the driving signal generating unit provides the driving signal so that the driving signal in a fluctuation range in which an undesirable level fluctuation may be present, corresponds to a constant working range of the modulation device, the light transmittance thereof staying at a constant value in the constant working range.

Abstract: An optical medium, which may be nonlinear, is provided with a matrix of conductors ("select lines") parallel to a face (planar surface) of the optical medium. The select lines are preferably superconductive, and are arranged in a two offset planar, preferably orthogonal sets. Adjacent pairs of select lines in both sets of select lines define discrete volumes, or "cells" within the optical medium. Light directed through the cells is refracted at angles determined by the quiescent optical properties of the optical medium, and may be "steered" to different angles by current passing through the select lines.