Abstract: State of polarization detectors and polarization control systems are disclosed. For example, the invention features an integrated optical assembly including: (i) a series of polarization-sensitive interfaces defining an optical beam path for an input optical beam to pass through the assembly, wherein each polarization-sensitive interface derives a sample beam from the input beam; and (ii) one or more retardation layers each positioned between a different pair of the polarization-sensitive interfaces, wherein the retardation layers are integrally coupled with the polarization-sensitive interfaces, and wherein the retardation layers and polarization-sensitive interfaces cause each sample beam to have an intensity that provides different information about the state of polarization of the input beam.

Abstract: An electrically controllable azimuth optical rotator (10) includes a first quarterwave plate (16) for receiving a first beam of electromagnetic energy (22) having a first arbitrary polarization state, and outputting a second beam (122) in response to the first quarterwave plate (16). An electric voltage controlled ferro-electric variable phase retarder (20) aligned at approximately 45 degrees to the first quarterwave plate (16) receives the second beam 122 and provides a third beam 38 in response to the retarder (20). The electric voltage controlled ferro-electric variable phase retarder (20) is characterized by a phase shift of &phgr;=2&agr;, where &agr; is a desired angle of rotation of the first arbitrary polarization state. To provide a voltage-controlled rotation, a second quarterwave plate (18) is aligned either parallel or perpendicular to the first quarterwave plate (16) for receiving the third beam (38) and outputting a fourth beam (46) in response to the retarder (20).

Abstract: The present invention is directed to an electrically switchable laminate construction for applications including smart windows, and other uses and applications in which light management is desired. The electro-optical laminate construction has scattering and transparent modes of operation for dynamically controlling electromagnetic radiation flow.

Abstract: A light modulator is comprised of two unit devices each using surface plasmon generated at the interface between thin metal films respectively formed on prisms and an electro-optical material, and a mirror. Both of the transmitted light due to absorption and re-radiation, and the reflected light arising from the unit devices are made into the outgoing light, the incident light on the next unit device, or the incident light on the mirror. Consequently, all light beams can be utilized as the final outgoing light beams with no loss of light. Further, the color of light can be spatially divided, and still further, it can also be temporally divided by changing the wavelength due to a voltage. As a result, the original light can be divided both temporally and spatially with almost no loss by combining two unit devices so configured as to re-radiate the absorbed light by surface plasmon using surface plasmon and a mirror, and thus utilizing both of the reflected light and the transmitted light.

Abstract: A light modulator is comprised of two unit devices each using surface plasmon generated at the interface between thin metal films respectively formed on prisms and an electro-optical material, and a mirror. Both of the transmitted light due to absorption and re-radiation, and the reflected light arising from the unit devices are made into the outgoing light, the incident light on the next unit device, or the incident light on the mirror. Consequently, all light beams can be utilized as the final outgoing light beams with no loss of light. Further, the color of light can be spatially divided, and still further, it can also be temporally divided by changing the wavelength due to a voltage. As a result, the original light can be divided both temporally and spatially with almost no loss by combining two unit devices so configured as to re-radiate the absorbed light by surface plasmon using surface plasmon and a mirror, and thus utilizing both of the reflected light and the transmitted light.

Abstract: The present invention is a method in which microcapsules are placed at desired locations selectively accurately and easily to produce a high accuracy electrophoretic display panel. In the production method of a display panel of the present invention, the microcapsules (43) are uniformly coated onto a substrate (41), on which electrodes (42) is formed by using an optical hardening resin as a binder material (44). Next, the binder material (44) is hardened by selectively irradiating a light beam to the only locations desired for placing the microcapsules (43) by using a photomask (45). The binder material (44) of portions not hardened is removed by washing in water. Thus, the microcapsules can be selectively and accurately placed at the only desired positions.

Abstract: The present invention relates to an energy recovery apparatus without a source capacitor.

Abstract: A joystick module in which a toggle arm controls movement of a plurality of shutters, with each shutter arranged between a light receiver and a light emitter. Control of the light from the light receiver to the light emitter of each pair provides signal information for controlled operation of an activity.

Abstract: The amplitude of an input laser beam is modulated by a two-dimensional array of Michelson interferometers comprised of a phase spatial light modulator, a mirror and a 50/50 light beamsplitter. The array of Michelson interferometers is calibrated by adjusting the path length of one of the interferometer arms. The calibration is maintained with the aid of feedback. The amplitude-modulated beam is then directed successively through a field imaging telescope, a polarization beamsplitter, and a quarter-wave plate before impinging a second phase spatial light modulator. The second spatial light modulator is adjusted to apply the desired phase profile. The beam, which at this point has the desired amplitude and phase profiles, is then again directed through the quarter-wave plate and subsequently reflected off of the polarization beamsplitter, out of the apparatus, and into free space.

Abstract: The invention is an instrument for sensing the state of polarization (SOP), and for transforming the SOP of a beam of light from an incident continuously-varying arbitrary SOP to a desired exit SOP, using a polarization compensator under feedback control. A polarization sensor uses two or three samples of a beam to sense the Poincare sphere latitude and longitude error in SOP. A polarization controller adjusts the SOP of light, which is then sensed by the polarization sensor, which develops signals to drive the polarization compensator using feedback methods. Unlike prior-art systems, the feedback seeks a mid-point rather than an extremum in the sensed signals, so there is no sign ambiguity in the feedback control. Further, the sensor signals indicate orthogonal displacements in SOP that correspond to specific elements in the polarization controller, so there is no ambiguity as to which element needs adjustment in order to correct a given error in SOP.

Abstract: A method and system is disclosed for switching signals between at least one optical fiber and a plurality of nodes through free space. The invention includes a switch that comprises at least one switch element. The switch element can detect signals transmitted by the optical fiber, at least one node, or both. The switch element can also transmit signals to the optical fiber, at least one node, or both. A mirror is provided for reflecting signals to and from the nodes through free space. An imaging telescope may also be provided for imaging light on to the mirror from the switch element.

Abstract: A method and apparatus for achieving dynamic intensity modulation of the channels in a wavelength-division multiplexed optical communication system is presented. Wavelengths are spatially separated into a plurality of channels, the polarization states of which are individually modulated. The channels can be combined or filtered by polarization states to achieve the desired intensity in the output signal. An exemplary embodiment includes at least a polarization modulator, a birefringent wedge, a lens, and a dispersive element (e.g., diffraction grating) arranged in various order. Each segment of the polarization modulator can be made to rotate the polarization direction of an incident channel by a specified angle. A half-wave plate may be inserted between the second dispersive element and the second birefringent wedge to eliminate polarization-dependent loss. Optionally, a parallel birefringent plate may be inserted after the second birefringent wedge to reduce polarization mode dispersion.

Abstract: A tuneable optical filter having a variable wavelength transmittance. The filter comprises a pre-polariser, a post-polariser and a birefringent plate positioned between the pre-polariser and the post-polariser. A twisted nematic liquid crystal cell (TN LCD) is positioned between the pre-polariser and the post-polariser, the TN LCD being controlled, in use, to tune the filter. A quarter wave plate is positioned adjacent the birefringent plate.

Abstract: An apparatus for processing an optical beam has at least one variable optical element to dynamically alter the polarization state of a polarized optical beam to form a polarization-altered optical beam. The polarization-altered optical beam includes elliptical polarization. The at least one variable optical element is a compound birefringent crystal with a designed retardation response to temperature variations. In one embodiment, the compound birefringent crystal has a designed retardation response that is substantially invariant with operating temperature variations. At least one wave plate processes the polarized optical beam. Each wave plate has a selected retardation, order of retardation, and orientation.

Abstract: A light modulator is comprised of two unit devices each using surface plasmon generated at the interface between thin metal films respectively formed on prisms and an electro-optical material, and a mirror. Both of the transmitted light due to absorption and re-radiation, and the reflected light arising from the unit devices are made into the outgoing light, the incident light on the next unit device, or the incident light on the mirror. Consequently, all light beams can be utilized as the final outgoing light beams with no loss of light. Further, the color of light can be spatially divided, and still further, it can also be temporally divided by changing the wavelength due to a voltage. As a result, the original light can be divided both temporally and spatially with almost no loss by combining two unit devices so configured as to re-radiate the absorbed light by surface plasmon using surface plasmon and a mirror, and thus utilizing both of the reflected light and the transmitted light.

Abstract: A photonic device including an array of lasers providing light to an array of electro-absorption modulators, both on a common substrate. In some embodiments the lasers are in a closely spaced array and lase at different wavelengths, providing with associated electro-absorption modulators a compact wavelength selectable laser.

Abstract: An optical imaging system including a wide-angle Cartesian polarizing beam splitter, light valve illumination optics having an f/#≦2.5, and at least one reflective light valve. The Cartesian polarizing beam splitter (PBS) has a structural orientation defining fixed polarization axes. The use of a Cartesian PBS allows the development of systems using curved PBS that provide higher light output and/or replace or augment other optical components. By recognizing and advantageously applying properties of wide-angle Cartesian polarizers, the present invention discloses a high-efficiency optical imaging system capable of functioning at f/#'s equal to or below f/2.5 while maintaining a contrast ratio of at least 100 to 1, or, more preferably, 150 to 1 in a projection system configuration.

Abstract: An electro-optical device is provided having a structure which, in particular, allows the device to be made smaller and thinner, and the heat-dissipation capability to be increased in order to prevent overheating. A positioning section which accommodates an opposing substrate, and which contacts an edge of an element substrate is provided in a case member accommodating an electro-optical panel which consists of the opposing substrate and the element substrate.

Abstract: Apparatuses, methods, and systems are disclosed that provide for simultaneously upconverting electrical signals carrying information at electric frequencies onto optical subcarrier lightwave frequencies that are greater and less than the carrier frequency of the lightwave onto which the electrical frequencies were upconverted. The upconversion of the electrical signals can be performed with or without suppression of the optical carrier frequency.

Abstract: An optical switching system, device, and method are disclosed that are capable of providing high throughput optical signal switching. Bandpass filters are provided for narrow-band demultiplexing of an optical signal to a plurality of switching elements. The system includes a demultiplexing device for wide-band wavelength demultiplexing to a plurality of optical switching devices.

Abstract: This invention enables a plurality of switch elements, each capable of receiving and transmitting a specific wavelength of light, to exchange information and to multiplex temporally-encoded information in time from two or more of the local processors. The process is accomplished by the use of an intermediate plane that has one or more ports that can detect light over a broad band of wavelengths, and that can transmit light at one or more specific wavelengths back to the local processors. The ports may be used to transmit time multiplexed and/or wavelength multiplexed signals.

Abstract: A projection display is used to process a light beam that includes first, second and third color components and that is to be provided to a projection lens. The projection display includes a dichroic beam splitter which separates the first color component from the second and third color components. A first polarization beam splitter prism cooperates with a first reflective light valve to process the first color component. A second polarization beam splitter prism cooperates with second and third reflective light valves to process the second and third color components. A third polarization beam splitter prism is disposed so as to direct the processed color components from the first and second polarization beam splitter prisms to the projection lens.

Abstract: The invention is an instrument for sensing the state of polarization (SOP), and for transforming the SOP of a beam of light from an incident continuously-varying arbitrary SOP to a desired exit SOP, using a polarization compensator under feedback control. A polarization sensor uses two or three samples of a beam to sense the Poincare sphere latitude and longitude error in SOP. A polarization controller adjusts the SOP of light, which is then sensed by the polarization sensor, which develops signals to drive the polarization compensator using feedback methods. Unlike prior-art systems, the feedback seeks a mid-point rather than an extremum in the sensed signals, so there is no sign ambiguity in the feedback control. Further, the sensor signals indicate orthogonal displacements in SOP that correspond to specific elements in the polarization controller, so there is no ambiguity as to which element needs adjustment in order to correct a given error in SOP.

Abstract: An optical device having a first input for at least one input optical signal having a random state of polarization and a first optical element capable of dividing, in space, the input optical signal into a pair of optical signals which are substantially parallel and have a predetermined state of polarization perpendicular to each another. The optical device also having a first crystal element for propagation, in free space, of at least the pair of optical signals coming from the first optical element, and the first crystal element being devoid of internal separation planes, and having electro-optical properties and being associated with electrodes so as to apply a voltage in a direction substantially perpendicular to the direction of propagation, along the first crystal element, of the at least one pair of optical signals.

Abstract: A switch device and method is disclosed that is capable of switching wavelength division multiplexed optical signals. The device comprises a switch element that may include a beam splitter, a plurality of wave plates, and a plurality of micro-electromechanical mirrors. The beam splitter is adapted to transmit light in one polarization and reflect light another polarization. The wave plates are adapted to change the polarization of the light so that the beam splitter either reflects or transmits the light. The micro-electromechanical mirrors are adapted to position the beam of light so that it is directed to a selected target.

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: Efficient color filtering and beam steering by combining the total internal reflection and the electro-optic effect in a special way.

Abstract: The or each strained quantum well layer of a quantum confined Stark effect modulator is provided with a substructure of substructure layers not all having the same lattice constant. The thickness and composition of these substructure layers may be arranged to produce a differential strain that is asymmetric with respect to the mid-plane of the quantum well and so skews the hole wavefunctions for heavy-holes, HH1, and light-holes, LH1, in opposite directions. This enables the choice of composition designed to provide substantial matching of the E1-HH1 and E1-LH1 Stark shifts for one particular polarity of applied field, thereby providing a modulation facility that is substantially polarisation insensitive. Alternatively, the thickness and composition of the layers may be chosen to produce a symmetrical strain profile in which the same effect is provided, but for both polarities of applied field.

Abstract: An apparatus and a method for stepper exposure control by utilizing a shutter assembly formed of electro-optic crystal materials in a photolithographic process are disclosed. In the apparatus, a series of control panels are stacked together to form a shutter assembly. Each of the control panel is formed by depositing a multiplicity of parallel, spaced-apart lines of electro-optic crystal material on a polarizer sheet. Two of such polarizer sheets are then stacked together with the lines parallel to each other and the lines on the top panel overlapping the spacing on the bottom panel. Two bottom panels are formed similarly however, positioned with the lines perpendicular to the lines in the first and second control panel when assembled together in the shutter assembly. A suitable electro-optic crystal material used should withstand a high temperature environment. One of such suitable material is LiNbO3.

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: A semiconductor optical modulator which, with a relatively simple configuration, eliminates phase modulation of output light from the semiconductor optical modulator by applying a voltage to a light absorption layer on the modulator. A nonlinear optical material layer changing refractive index is located in the direction of light propagation and cancels, in the output light, the phase modulation that is generated due to light intensity variations in the light absorption layer.

Abstract: Generally speaking, in accordance with the invention, an optical transmission modulation apparatus is provided for modulating light transmitted through the apparatus. The apparatus comprises a metal film having a periodic array of subwavelength-diameter holes provided therein, and a supporting layer. At least a portion of the supporting layer has a selectively variable refractive index, the selectively variable refractive index portion being substantially adjacent to the metal film such that the metal film and the supporting layer form a perforated metal film unit. Selective variation of the refractive index of the selectively variable refractive index portion modulates the intensity of the light transmitted through the perforated metal film unit without substantially changing the direction of the light. Flat panel displays, spatial light modulators and tunable optical filters based on the optical transmission control apparatus are also provided.

Abstract: A method and apparatus for overcoming polarization induced signal fading in both heterodyne communication and interferometric sensing. An adjustable birefringent element in series with a linear-polarization beam splitter forms an elliptical-polarization beam splitter. The birefringent element controllably evolves the states of polarization of two input signals thereby controlling the power contribution of each signal onto the orthogonal axes used by the linear beam splitter. When the states of polarization are evolved such that there are equal signal to reference power ratios on the beam splitter axes, subsequent detectors generate a constant, optimum amplitude signal without the need for weighting or decision circuits.

Abstract: Two polarization conversion element arrays are disclosed. Each polarization conversion element array is composed of a plurality of polarization conversion elements for converting light incident upon the polarization conversion element array to a linearly polarized light beam with a predetermined polarization direction. The plurality of polarization conversion elements are disposed opposite to each other with a predetermined space provided between at about the center of the light-outgoing surface of a lens array in the direction of arrangement. Of the light beams (s-polarized+p-polarized light beams) gathered by the lens array, light beam that is not incident upon the polarization conversion element and passes through the predetermined space is a light beam including a predetermined polarized light beam (s-polarized light beam) that is primarily made to leave the array 320a and an ineffective polarized light beam (p-polarized light beam).

Abstract: A method for mechanically stabilizing and for tuning a filter having a photonic crystal structureThe cavities of the filter fabricated as a photonic crystal structure are filled with optically transparent material having an adjustable refractive index. The optical properties of the filter and, thus, the filtering action are adjusted by way of an electric field having a variable field strength.It is possible to produce small-dimensioned, narrow-band filter elements, which are finely tunable and tunable within a broad range, and to realize them as filter elements which are integrated with a high packaging density.

Abstract: A photonic band gap structure device and method for delaying photonic signals of a predetermined frequency and a predetermined bandwidth by a predetermined delay is provided. A Fabry-Perot delay line device has several regions of periodically alternating refractive material layers which exhibit a series of photonic band gaps and a periodicity defect region, interposed between the regions of periodically alternating refractive material layers. The Fabry-Perot delay line device imparts a predetermined delay to photonic signals that pass therethrough. The introduction of the periodicity defect region into this photonic band gap structure creates a sharp transmission resonance within the corresponding photonic band gap of the structure and causes at least an order of magnitude improvement in photonic signal delay for a band-edge delay line device of similar size. Variable photonic delays to multiple photonic signals are also generated by this Fabry-Perot delay line device.

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: Incident light 1 is inputted to an electro-absorption-type optical modulator 4 via an optical circulator 2 and a lens 3, and subjected to intensity modulation that corresponds to a modulation signal 8. The optical signal outputted by the electro-absorption-type optical modulator 4 is inputted to a Faraday rotator 6 via a lens 5, and the plane of polarization is rotated 45.degree.. The optical signal transmitted by the Faraday rotator 6 is totally reflected by a totally reflecting mirror 7, inputted for the second time to the Faraday rotator 6, then passed through the lens 5 after the plane of polarization has been rotated 45.degree. by this Faraday rotator 6, and readmitted by the electro-absorption-type optical modulator 4. The output of the electro-absorption-type optical modulator 4 is emitted via the lens 3 and the optical circulator 2. The polarization dependence of insertion loss can be eliminated because the plane of polarization is rotated 90.degree.

Abstract: An ladder-structured variable delay device for providing variable true time delay to multiple optical beams simultaneously. The device comprises multiple basic units stacked on top of each other resembling a ladder. Each basic unit comprises a polarization sensitive corner reflector formed by two polarization beamsplitters and a polarization rotator array placed parallel to the hypotenuse of the corner reflector. Controlling an array element of the polarization rotator array causes an optical beam passing through the array element to either go up to a basic unit above it or reflect back towards output. The beams going higher on the "ladder" experience longer optical path delay. Finally, the ladder-structured variable device can be cascaded with another multi-channel delay device to form a new device which combines the advantages of the two individual devices. This programmable optic device has the properties of high packing density, low loss, easy fabrication, and virtually infinite bandwidth.

Abstract: A method and apparatus is provided for locating with improved vertical positioning accuracy a discrete element on a semiconductor optoelectronic integrated circuit. The method employs an etch stop layer located beneath a series of semiconductor layers. The semiconductor layers may include waveguides to couple light between integrated or discrete elements. Pits with accurate depth are etched in the semiconductor layers down to the etch stop layer. Accurate alignment between a discrete element and another element is made possible by controlling their respective distances from the etch stop layer.

Abstract: An electro-optical device such as an optical deflector comprising a ferro-electric substrate, electrodes provided on principal surfaces of this substrate and an inverted domain having a polygonal, e.g. triangular shape formed in the substrate, at least one of the domain walls of these domains being effectively perpendicular to the principal surfaces of the substrate, and a light beam passing through at least two of the domain walls, thus permitting fast random access, wide deflection angle and high resolution.

Abstract: There is provided an electrochromic device comprising a pair of transparent substrates facing each other, a pair of transparent electrodes facing each other between the pair of transparent substrates, and an electrochromic layer and a transparent ion conductive layer sandwiched by the pair of transparent electrodes, wherein at least the electrochromic layer and the transparent ion conductive layer are coated with a resin in a state that carrier precursor in the electrochromic layer and in the transparent ion conductive layer is ionized. As a result, film breakage of the electrochromic device and peeling off of the sealing resin and the sealing substrate are prevented, thus improving the durability of the electrochromic device.

Abstract: An optical functional device includes a semiconductor substrate, an optical functional layer provided on said semiconductor substrate and selected from the group consisting of a light emitting layer, a light absorbing layer, and an optical waveguide layer. The optical functional layer has a multi-quantum well layer. Preferably, the semiconductor substrate is a nonplanar semiconductor substrate having a ridge and two grooves adjacent said ridge, said ridge having a ridge width of from 1 to 10 .mu.m, a ridge height of from 1 .mu.m to 5 .mu.m, and a gap distance of from 1 .mu.m to 10 .mu.m. Such an optical functional device can be fabricated by growing, on a nonplanar semiconductor substrate having a specified dimension of the ridge, a strained multi-quantum well layer by metalorganic vapor phase epitaxy. Integrated optical device or circuit preferably includes an optical functional device on the nonplanar semiconductor substrate of a specified range of ridge shape factors.

Abstract: An instrument is provided for measuring the temperature of an object from infrared radiation emitted by the object. The instrument includes a radiation detector, a temperature indicating device connected to the detector, and a modulator disposed in a path of a radiation beam from the object for converting the beam into a series of pulses when the modulator is vibrated in and out of the path. The modulator includes a primary piezoelectric element adapted to vibrate when subjected to driving signals at a frequency related to the resonant frequency of the modulator, and a secondary piezoelectric element connected with and driven by the primary piezoelectric element. The secondary piezoelectric element is electrically insulated from the primary piezoelectric element. The modulator also includes a blocking element connected with the secondary piezoelectric element and disposed to move in and out of the path of the beam.

Abstract: An optical functional device includes a semiconductor substrate, an optical functional layer provided on said semiconductor substrate and selected from the group consisting of a light emitting layer, a light absorbing layer, and an optical waveguide layer. The optical functional layer has a multi-quantum well layer. Preferably, the semiconductor substrate is a nonplanar semiconductor substrate having a ridge and two grooves adjacent said ridge, said ridge having a ridge width of from 1 to 10 .mu.m, a ridge height of from 1 .mu.m to 5 .mu.m, and a gap distance of from 1 .mu.m to 10 .mu.m. Such an optical functional device can be fabricated by growing, on a nonplanar semiconductor substrate having a specified dimension of the ridge, a strained multi-quantum well layer by metalorganic vapor phase epitaxy. Integrated optical device or circuit preferably includes an optical functional device on the nonplanar semiconductor substrate of a specified range of ridge shape factors.

Abstract: An interferometric switch for spatially switching either linearly polarized or unpolarized externally derived beams of substantially coherent light includes an optical input unit for dividing an externally derived light beam into a constituent beam pair. An optical phase modulating device includes a nematic liquid crystal pixel for selectively shifting the relative phase of the constituent beam pair. An output unit cooperates to combine respective components of the constituent beam pair along coincident collinear paths so as to form a respective output light beam directed along a selected one of first and second output axes, according to the relative phase imparted by the phase-modulating device. The phase modulating device may comprise a cascading arrangement of pixel stages which can respectively provide a selected incremental phase-shift to each constituent beam passing therethrough.

Abstract: A method and apparatus for overcoming polarization induced signal fading in both heterodyne communication and interferometric sensing. An adjustable birefringent element in series with a linear-polarization beam splitter forms an elliptical-polarization beam splitter. The birefringent element controllably evolves the states of polarization of two input signals thereby controlling the power contribution of each signal onto the orthogonal axes used by the linear beam splitter. When the states of polarization are evolved such that there are equal signal to reference power ratios on the beam splitter axes, subsequent detectors generate a constant, optimum amplitude signal without the need for weighting or decision circuits.

Abstract: A raster output scanning system is disclosed which utilizes a single light source, an electro-optical device and a beam-splitter to generate two light beams in order to simultaneously scan two adjacent scan lines. Two different trains of pixel information are used to control the intensity of the laser light source and the degree of the polarization of the electro-optical device in order to modulate the two light beams with two separate trains of pixel information without using a modulating device. Each of the two light beams exiting the beam-splitter is modulated in accordance with one of the two trains of pixel information.

Abstract: Full complex spatial light modulation is enabled by an optically additive combination of the actions of separate and independent spatial light modulators, even though the independent modulators can each express only a one-parameter subset of complex values called its operating curve. Similarly the operating curve of a single modulator can be shifted (biased) by optically adding a constant complex value.

Abstract: Apparatus for rotating polarization of polarized light includes an input of linearly polarized light, a variable retarder for retarding the phase of one quadrature component of such linearly polarized input light an amount relative to the phase of the other quadrature component, and an analyzer for converting such quadrature components to linearly polarized light having a plane of polarization that is a function of the amount of such phase retardation. By changing the electrical input to the retarder the amount of rotation can be altered.