Abstract: An improved linear light modulator array is formed with opposing electrodes which extend away from the optic surfaces of optoelcctronic material used to form the array. A uniform electric field is created across a modulator volume, generally perpendicular to light propagation within the modulator volume. The modulator volume of an element in the array is a function of electrode length, width and separation. Additional elements are defined by additional pairs of electrodes. The geometry is obtained by cutting optoelectronic material into strips. Cut sides of the strips are metallized, one at a time, with the opposite side temporarily affixed to a carrier. Aligned trenches are cut in the metallized strips to separate electrode pairs and define array elements.

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: An optical modulator that modulates light through the semiconductor substrate through the back side of a flip chip packaged integrated circuit. In one embodiment, an optical modulator is disposed within a flip chip packaged integrated circuit die. The optical modulator includes a deflector and a diffraction grating. A first infrared optical beam having a photon energy less than the band gap energy of the semiconductor substrate is directed through the back side of the semiconductor substrate of the integrated circuit die, deflected off the deflector through the diffraction grating and back out the back side of the integrated circuit die. A second infrared optical beam having a photon energy greater than or equal to the band gap energy of the semiconductor substrate is directed through the back side of the semiconductor substrate to generate free charge carriers and increase the modulation depth of the optical modulator.

Abstract: An optical correlator includes a first reflective mode spatial light modulator for inputting an input image and a second reflective mode spatial light modulator for inputting a reference image for comparing with the input image. The optical correlator also includes an optics arrangement for (i) directing light into the first spatial light modulator, (ii) directing light along a first optical path from the first spatial light modulator into the second spatial light modulator, and (iii) directing light along a second optical path from the second spatial light modulator into an image plane. The optics arrangement includes a first lens having a focal length f1 and a second lens having a focal length f2. The first lens is positioned substantially adjacent the first spatial light modulator and the second lens is positioned substantially adjacent the second spatial light modulator.

Abstract: The invention relates to a display operating either in a reflective mode or a transmissive mode and having a high brightness. The display comprises pixel elements (20) having a switchable layer (3), which is switched between a reflecting, a transmissive and an absorbing state by changing a hydrogen content of the switchable layer. Applying a DC voltage on electroconductive layers (11, 13) changes the hydrogen content. These electroconductive layers sandwich a stack of layers comprising the switchable layer (3), which stack has been deposited on a transparent substrate.

Abstract: An Interferometric Modulator (IMod) is a microelectromechanical device for modulating light using interference. The colors of these devices may be determined in a spatial fashion, and their inherent color shift may be compensated for using several optical compensation mechanisms. Brightness, addressing, and driving of IMods may be accomplished in a variety of ways with appropriate packaging, and peripheral electronics which can be attached and/or fabricated using one of many techniques. The devices may be used in both embedded and directly perceived applications, the latter providing multiple viewing modes as well as a multitude of product concepts ranging in size from microscopic to architectural in scope.

Abstract: This invention relates to a scattering transflector wherein the reflectivity of a surface of the transflector is dependent on the angle at which light is incident on the surface of the transflector. This invention also relates to a display device comprising an optical modulating element and the foregoing scattering transflector.

Abstract: In an image resolving detector arrangement, an image of an object scene is generated by an imaging optical system. Radiation from a respective one of several adjacent image elements of an image area associated with the detector element is directed consecutively onto each of the detector elements by an image element selection device. Herein the image element selection device is formed by a micro-light stop raster, which is arranged in an image plane and moveable step by step in this image plane, and which, in each position, allows only radiation from a part of an image area associated to a detector element to pass onto the detector element. Thereby, the resolution of the image resolving detector arrangement is improved.

Abstract: An image display device comprising a light modulation panel, a light conductor arranged opposite the light modulation panel and a light source connected to the light conductor. The light conductor comprises a serrated foil which reflects a light beam emitted by the light source and having a first direction of polarization, and transmits a light beam modulated by the light modulation panel and having a second direction of polarization.

Abstract: An adaptive pulse compressor is described, especially for use with ultrashort pulses, wherein the input pulses are modified in an iterative fashion, according to a feedback signal obtained from measurement of the output pulses. The feedback signal is programmed, by means of a programmable spatial light modulator, to allow for independent control of the individual spectral components of the incoming pulses, such that almost arbitrary phase functions can be realized to accomplish efficient compression. One of the main disadvantages associated with prior art pulse compressors, namely, the need for characterization of the uncompressed pulses, is thus eliminated. The compressor is thus capable of handling completely uncharacterized or from time varying sources.

Abstract: An optical device including a substrate, a distributed feedback (DFB) semiconductor laser formed on the substrate and including a diffraction grating having an asymmetrical &lgr;/4 phase shift region, the diffraction grating extending along an optical axis of the DFB semiconductor laser, and a field absorbing modulator integrated with the DFB semiconductor laser on the substrate for modulating a light wave emitted from the DFB semiconductor laser, the optical modulator having a facet reflection rate between 0.01 and 0.02% at an output end thereof, the difraction grating having a □L value between 1 and 1.2 The proper combinations of the □L value of the diffraction grating and the reflection rate of the output facet of the modulator of the DFB semiconductor laser can fabricate the source for integrating the modulator having the excellent quality with a higher yield and lower cost.

Abstract: An illumination system and display are disclosed that include a light for providing light, a polarizing beam splitter (PBS) having a first surface that receives the light from the backlight. The PBS passes a first polarization of the received light to a curved mirror located at a second PBS face, which second PBS face is opposite the first PBS face. The curvature of the mirror provides the optical power necessary for proper imaging, while limiting the reflecting area of the mirror provides an aperture stop that determines the numerical aperture of the optical system. The display also includes a quarter wave plate and a spatial light modulator (SLM). The quarter wave plate is located between the PBS and mirror and changes the first polarization of light, directed from the PBS to the mirror, to a second polarization which is reflected from the mirror back to the PBS.

Abstract: An optical filter for correcting non-linear gains across a wavelength band includes a first layer having a first layer thickness according to the formula: first layer thickness=m&lgr;/(4nfirst), where m is an odd multiple integer, &lgr; is the central wavelength of the wavelength band, and nfirst is the refractive index of the first layer, and a second layer having a second layer thickness according to the formula: second layer thickness=&lgr;/(4nsecond), where &lgr; is the central wavelength of the wavelength band, and nsecond is the refractive index of the second layer. The optical filter introduces an insertion loss for wavelengths in a wavelength band of optical fiber transmission having an insertion loss curve approximating a quadratic shape in the wavelength band and having a maximum insertion loss at a central wavelength of the wavelength band.

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: A spatial light modulator with an anti-reflective coating (ARC) 100 integrated into its structure. The manufacturing of the device is altered to include deposition of an ARC 100, and any necessary patterning and etching to allow the elements of the array to operate properly. The ARC could reside in several places of the element structure including over the addressing circuitry 26, over a middle layer 32 or on the underside of the reflective structure 10. Micromechanical spatial light modulators, as well as non-moving modulators, such as reflective and transmissive LCD modulators can use the invention.

Abstract: An optical modulator that modulates light through the semiconductor substrate through the back side of an integrated circuit die. In one embodiment, the optical beam enters through the back side of the semiconductor substrate at a first location. The path of the optical beam is altered such that the optical beam passes through and along and through a path parallel or nearly parallel to the front side of the semiconductor substrate. In one embodiment, the optical modulator includes a charged layer through which the optical beam is directed along the path parallel or nearly parallel to the front side. In one embodiment, the charge concentration of free charge carriers is modulated in response to a signal of the integrated circuit die, resulting in modulation of the optical beam.

Abstract: An optical switch uses a micromachined adjustable phase hologram device to route optical signals from an input fiber to selected output fibers is described. The adjustable phase hologram includes a large number of micromachined reflective ribbons which can be individually controlled and adjusted to produce a wide range of phase profiles to route the light beams from the input fiber. This optical switch is capable of dealing directly with optical signals, has fast switching speeds, is capable of routing WDM input signals, is polarization independent, is scalable to large switches, and avoids the complexity of other switches.

Abstract: Through silicon optical modulators (TSOM) formed in a silicon integrated circuit comprise an array of MOSFET elements which cause optical phase shifts of reflected light to identify a state of a signal. A polarization of the reflected light is modified by the phase shift and transmits the signal. The polarization of reflected light can be controlled by the angle of the incident light, by polarizing optical slits fabricated in the modulator, or by using a polarized mirror. Either embodiment allows the polarized reflected light to be nulled out. As such, a polarization of the reflected light is altered when the signal is applied to the modulator. The altered polarization can then be detected.

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: Light in the visible spectrum is modulated using an array of modulation elements, and control circuitry connected to the array for controlling each of the modulation elements independently, each of the modulation elements having a surface which is caused to exhibit a predetermined impedance characteristic to particular frequencies of light. The amplitude of light delivered by each of the modulation elements is controlled independently by pulse code modulation. Each modulation element has a deformable portion held under tensile stress, and the control circuitry controls the deformation of the deformable portion. Each deformable element has a deformation mechanism and an optical portion, the deformation mechanism and the optical portion independently imparting to the element respectively a controlled deformation characteristic and a controlled modulation characteristic. The deformable modulation element may be a non-metal.

Abstract: A multistage stage deformable mirror structure (10) includes a backup structure (12) having a support surface; a single mirror facesheet (18) having an optical surface (18A); and, interposed between the support surface and the optical surface, at least one intermediate deformable structure (14) that is coupled at a first surface to the support surface through a first set of linear actuators (16) for being deformed by the set first set of actuators. The at least one intermediate deformable structure is also coupled at a second opposing surface to the optical surface through a second set of linear actuators (20) for deforming the optical surface. The optical surface assumes a shape that is a combination of the deformation imparted to the at least one intermediate deformable structure by the first set of linear actuators, and the deformation imparted to it by the second set of linear actuators.

Abstract: An optical display system includes a source of white uncollimated light, a color separator for separating the white light into spectral components, a reflective ferroelectric light valve for spatially modulating the spectral components, and a polarizing beam splitter for directing vertically polarized light towards a display lens. The system further includes a corrective film disposed in an optical path between the white light source and the light valve. The film, which may be made of a ferroelectric material or other birefringent material, ensures that retardance of the light valve is approximately 180 degrees or some other desired angle over a spectrum of interest. In this manner, the light valve is achromatized by the film.

Abstract: The invention provides a fiber-optic 2×2 switch using a dual-fiber 50:50 input coupler and a dual-fiber 50:50 output coupler. One fiber from each coupler makes contact to an inner transparent electrode on a planar layer of electro-optic material and the other fibers make contact to an outer transparent electrode on the layer. The electro-optic layer has its other side coated with a transparent electrode which is placed in optical contact with one end of a GRIN lens. The fibers are arranged so that the inner fibers are at conjugate points and the outer fibers also at conjugate points of the lens. The other end of the lens is coated with a mirror. Applying a voltage between either the inner or outer electrode changes the optical path length for the light from and to the fibers traveling through the material under the selected electrode causing the light from the two input fibers to be switched between the two output fibers. 2×N switches can be constructed by concatenating 2×2 switches.

Abstract: A method for transferring an image to a medium includes: generating a substantially uniform line of radiation; producing diffractive light from the uniform line of radiation; passing zero order diffractive light to the medium in a telecentric fashion while blocking non-zero order diffractive light; adjusting image magnification on the medium independent of image focus in response to the zero order diffractive light; and adjusting image focus on the medium independent of image magnification in response to the zero order magnification-adjusted diffractive light.

Abstract: An optical modulator that modulates light through the semiconductor substrate through the back side of an integrated circuit die. In one embodiment, an optical modulator is disposed within a flip chip packaged integrated circuit die. The optical modulator includes a modulation region through which an optical beam is passed a plurality of times. In one embodiment, the optical beam enters through the back side of the semiconductor substrate at a first location and the modulated optical beam is deflected out through a second location on the back side of the semiconductor substrate. The interaction length of the optical modulator is increased by internally deflecting and passing the optical beam through the modulation region a plurality of times. In one embodiment, total internal reflection is used to deflect the optical beam. In another embodiment, reflective materials are used to internally deflect the optical beam.

Abstract: A polarization conversion system comprises a polarized light selective reflector that divides incident unpolarized light into first and second types of polarized light, transmits the first type of polarized light and reflects the second type of polarized light, a relay optical system that relays an incident light beam onto the polarized light selective reflector, a polarized light reflector, disposed on an optical path of a reflected light beam reflected by the polarized light selective reflector, that reflect the reflected light beam back to the polarized light selective reflector while converting the second type of polarized light to polarized light of the first type.

Abstract: A micromechanical tilt mirror device that includes a membrane suspended by its ends over a substrate such that a mirror area of the membrane is asymmetrically positioned on the membrane whereby it is tilted when the membrane is deformed by electrostatic forces. This mirror tilt is used to steer an incident light beam in a prescribed direction. The mirror can be supported to provide tilt in either of two orthogonal directions with respect to a rest direction.

Abstract: There is provided a device for use with fiber-optic cables for polarization insensitive amplitude modulation of light comprising a planar electro-optic layer with a reflective conductive mirror electrode on one side and a pair of transparent conductive electrodes on the other. The transparent conductive electrodes have a small separation along a straight line. A GRIN lens has one end in optical contact with the transparent conductive electrodes with its axis located over the line separating the electrodes. An input optical fiber and an output optical fiber are placed in optical contact with the other end of the lens at points which are symmetrically displaced from the axis of the lens. Light coming from input fiber is collimated by the GRIN lens and directed to the transparent electrodes, through the electro-optic layer and to the mirror from which it is reflected and refocused by the GRIN lens onto the output fiber.

Abstract: A through silicon optical modulator alters a phase of a light beam which enters the back of a silicon die. The modulator can be formed as a PMOS transistor fabricated in an n-well, or can be an NMOS transistor having a negative gate to substrate voltage. By modulating the well voltage (or gate potential) the phase of a portion of the reflected light is altered. Two accumulation layers are selectively formed in the light path which is reflected from the transistor gate electrode. The phase change is detected to provide a signal from the integrated circuit having the through silicon optical modulator structure.

Abstract: A light separation apparatus using a flat plate including a wide band anti-reflection coating film, first and second dichroic mirrors, a wide band high-reflection coating film, an anti-reflection coating film, and a material forming the flat plate. The wide band anti-reflection coating film allows an incident light beam generated by a light source to penetrate into the material at a first angle without reflection. The first dichroic mirror allows only a light beam with a first wavelength to penetrate at the first angle and reflects light beams with other wavelengths at the second angle. The high-reflection coating film reflects at a second angle the light beam reflected by the first dichroic mirror. The second dichroic mirror allows only a light beam with a second wavelength to penetrate outside the material at the first angle so that it is parallel to the light beam with the first wavelength penetrated through the first dichroic mirror.

Abstract: A retroreflecting modulator including a lens, a light guide, a light modulator, and a reflective surface. Incident light falls on the lens, where it is focused as a spot on a focal surface. The light guide transmits the focused light to the light modulator, where it is modulated and reflected back, via the reflective surface and light guide, to the lens. The lens emits the modulated light in the opposite direction as the incident light. The preferred light-receiving and focusing device is a specialty sphere lens, the preferred light guide is a fiber optic plate, and the preferred light modulator is a liquid crystal modulator. The retroreflecting modulator may be spatially-unresolvable, where a single signal modulates the light, or spatially-resolvable, where the modulation signal depends upon the direction of the incident light.

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: A modulator for modulating an incident beam of light having a wavelength .lambda. including a base having a surface; an electrode formed over the surface of the base; a plurality of equally spaced apart deformable elements arranged over the electrode and being disposed parallel to each other and secured at opposite ends of each spaced apart deformable element and suspended above the base and having at least two spaced apart conductive and reflective portions and a central reflective portion electrically insulated from the two spaced apart conductive and reflective portions and disposed therebetween; a reflective layer disposed over the base between the spaced apart deformable elements; and applying a potential between the electrode and the spaced apart conductive and reflective portions so that the spaced apart conductive and reflective portions are movable between first and second positions which are substantially .lambda./4 apart.

Abstract: A polarized-light converting elemental device which can produce an accurately unidirectionally and circularly polarized light with a minimized loss of light and a projection-type display device using said unidirectionally-polarized-light converting elemental device are provided. A polarized-light converting elemental device comprises a mirror glass portion consisting of an array of mirror glass blocks each having a first reflecting optical element and a second reflecting optical element and a cholesteric-liquid-crystal glass portion including a cholesteric liquid crystal layer for reflecting either clockwise circularly polarized component or anticlockwise circularly polarized component and transmitting the other. Natural light from the left side is split into two directions by the first reflecting optical element. Light reflected from the cholesteric liquid crystal is reflected by the second reflecting optical element to alter its rotation direction and then transmitted through the cholesteric liquid crystal.

Abstract: An optical modulator (39) includes a substrate (7) exhibiting an electro-optical Pockels effect and having first and second end surfaces (31, 33) opposite to each other. An optical waveguide (9) of a branched interferometer type is formed on the substrate (7) and has first and second branched waveguide portions (11, 13) with an input end and a reflection side end respectively exposed in the first and second end surfaces (31, 33) of the substrate (7). A modulating electrode (15) is formed on the substrate (7) in a vicinity of the branched interferometer type optical waveguide (9). A reflection plate (35) is mounted on the second end surface (33) of the substrate (7) at an angle of inclination (.theta.) with respect thereto. Still further, a spacer (41) is disposed between a side of the reflection plate (35) and the second end surface (33) of the substrate (7) to thereby define the angle of inclination (.theta.) of the reflection plate (35) with respect to the second end surface (33) of the substrate (7).

Abstract: Interference filters and filter arrays based on thin-metal film interference filters having at least one dielectric layer formed between two thin-metal films to form a Fabry-Perot cavity.

Abstract: A multi-gas sensor is provided which modulates a polarized light beam over a broadband of wavelengths between two alternating orthogonal polarization components. The two orthogonal polarization components of the polarization modulated beam are directed along two distinct optical paths. At least one optical path contains one or more spectral discrimination element, with each spectral discrimination element having spectral absorption features of one or more gases of interest being measured. The two optical paths then intersect, and one orthogonal component of the intersected components is transmitted and the other orthogonal component is reflected. The combined polarization modulated beam is partitioned into one or more smaller spectral regions of interest where one or more gases of interest has an absorption band.

Abstract: Light in the visible spectrum is modulated using an array of modulation elements, and control circuitry connected to the array for controlling each of the modulation elements independently, each of the modulation elements having a surface which is caused to exhibit a predetermined impedance characteristic to particular frequencies of light. The amplitude of light delivered by each of the modulation elements is controlled independently by pulse code modulation. Each modulation element has a deformable portion held under tensile stress, and the control circuitry controls the deformation of the deformable portion. Each deformable element has a deformation mechanism and an optical portion, the deformation mechanism and the optical portion independently imparting to the element respectively a controlled deformation characteristic and a controlled modulation characteristic. The deformable modulation element may be a non-metal.

Abstract: An optical system such as an add and/or drop WDM multiplexer allows the wavelength fluctuation of an optical carrier to be tracked so that a corresponding fiber Bragg grating (FBG) can be responsively tuned. The preferred embodiment of the wavelength tracking system in an optical system such as an add and/or drop module includes a three-port optical circulator, three optical fibers, a series of tunable FBGs, a source of a broadband optical noise signal, an optical spectrum analyzer (OSA), and an FBG tuner. In operation, an LED generates modulated probe lightwaves that are inserted into a drop module. The LED lightwaves and the optical carriers propagating through the drop module are monitored by an OSA. The monitoring procedure determines the conditions, in terms of target wavelengths of the FBGs, and the stability or instability of the optical carriers. The FBGs are then tuned in response to the FBG and optical carrier information.

Abstract: A polarization independent optical phase modulator comprises first and second substrates. A reflector is disposed between the first and second substrates and a quarterwave plate is disposed between the reflector and the first substrate. A polarization dependent electrooptic layer is disposed between the quarterwave plate and the first substrate. The quarterwave plate has an optic axis which is aligned at 45 degrees to the polarization whose phase is modulated by the electrooptic layer.

Abstract: An optical fiber compatible modulator device provides high-contrast levels switchable using modest applied voltages. As a two-port optical modulator, a normal light signal incident at a first port is deflected to a non-normal direction for passage through an absorption layer (e.g., a multiple-quantum well (MQW) layer), the absorption layer having an adsorption characteristic which changes as a function of a voltage applied across it. The non-normal direction light signal exiting the absorption layer is deflected to a normal light signal for output from a second port of the optical modulator. As a one-port optical modulator, a normal light signal received at a first port is deflected to a non-normal direction for passage through an absorption layer. A reflector reflects a non-normal direction light signal exiting the layer back through the layer to the deflector means and is output at the port of the optical modulator.

Abstract: The diffractive optical modulator of the invention includes: a plate having a portion functioning as a first electrode; a spacer layer formed on the plate; and a grating consisting of a plurality of beams having a portion functioning as a second electrode, both ends of the beams being supported on the spacer layer. In the diffractive optical modulator, by adjusting a voltage applied between the first electrode and the second electrode, a distance between the beams and the plate is varied, thereby controlling the diffraction efficiency. An insulating layer is further provided between the plate and the plurality of beams.

Abstract: The specification describes a double poly Mechanical Anti-Reflection Switch (MARS) device in which transition layers of SiN.sub.x are provided on either side of the air gap, and the thickness ratio of the two transition layers is adjusted to provide a tradeoff between the insertion loss of the device and the optical bandwidth.

Abstract: Disclosed is a driving circuit for an electro-absorption optical modulator for outputting intensity-modulated signal light by receiving carrier light from a light source and absorbing the carrier light in dependence upon a driving voltage. The driving circuit includes a driving unit for applying a pulsed driving voltage to an electro-absorption optical modulator, and a variable impedance unit connected in parallel with the electro-absorption optical modulator for matching impedance with respect to the driving unit. The impedance of the variable impedance unit is switched to one value when the driving voltage is applied to the electro-absorption optical modulator and to another value when the driving voltage is not applied to the electro-absorption optical modulator so as to match impedance with respect to the driving unit.

Abstract: The diffractive optical modulator of the invention includes: a plate having a portion functioning as a first electrode; a spacer layer formed on the plate; and a grating consisting of a plurality of beams having a portion functioning as a second electrode, both ends of the beams being supported on the spacer layer. In the diffractive optical modulator, by adjusting a voltage applied between the first electrode and the second electrode, a distance between the beams and the plate is varied, thereby controlling the diffraction efficiency. An insulating layer is further provided between the plate and the plurality of beams.

Abstract: A mechanical modulator is provided that includes a conductive substrate and at least three multilayer mirrors disposed on the substrate. The mirrors are spaced apart from one another to define upper and lower optical cavities. The upper cavity is formed by an airgap having a variable thickness. The multilayer mirror located above the airgap includes a conductive membrane having an optically transparent portion and a flexible support for orienting the membrane in a first position. Under the action of a bias, the membrane moves to a second position, changing the air gap by a fraction of a wavelength of the optical signal, as measured in air. The change in position of the membrane from the first to the second position causes a change in the total reflectivity of the modulator from a minimum to a maximum value.

Abstract: A reversible and conservative photon routing switch is implemented as a room temperature, optical, vertical cavity X-gate (also sometimes known as a Fredkin gate). Such gates are primitive structures into which all logic functions can be decomposed. The construction of the device makes it uniquely suited to dense packed arrays of optoelectronic components for optical routing and logic. In one of the switching states, light incident on the device from either side of the wafer will pass through the device (the device is bi-directionally transmissive). In the other switching state, light incident from either side of the wafer will be reflected. Switching can be performed using either electrical or optical control. Thus incident photons are either routed through the device or reflected from the device.

Abstract: A three-dimensional stereovision imaging system (20) adapted for use with a polarizing filter (22). The inventive system (20) includes a stereovision projector (24) for generating a projection (26) of alternating left and right images. A polarizer (30) polarizes electromagnetic energy corresponding to the images (26) and provides a polarized image (34) in response thereto. A twist liquid crystal screen (28) controlled by a twist liquid crystal controller (36) rotates the plane of oscillation of the polarized image (40) by a first twist angle synchronized with the alternating left and right images. Polarizing glasses (42) direct the polarized image (40) from the twist liquid crystal (28) into alternate eyes in response to the polarization state of the polarized image (40). In a specific embodiment, the polarizing glasses (42) have first (44) and second (46) eye-pieces with first (44) and second (46) linear polarizers, respectively.

Abstract: A liquid-crystal cell having plates defining a gap between them which is filled with a liquid crystal, especially a twisted nematic. The plates are made non-parallel to a predetermined degree so that the liquid crystal assumes a wedge shape, producing different effective thicknesses of the liquid crystal depending on the lateral position within the cell. In use, a narrow beam irradiates a portion of the cell, and the cell is positioned along the wedge direction so as to optimize the cell performance. The invention is particularly useful with a liquid-crystal multi-wavelength switch, which requires extinction ratios between the two states of the cell.

Abstract: An apparatus for modulating an optical signal and a method for fabricating such an apparatus, are disclosed. The apparatus, which may be formed on a semiconductor wafer or chip, consists of a membrane that is supported over a substrate by flexible support arms. An air gap is defined between the membrane and substrate. The membrane thickness and refractive index are chosen so that the reflectivities of the membrane and substrate are not 180.degree. out of phase. Under the action of bias, the membrane moves vertically from a first position to a second position relative to the substrate, changing the air gap. The reflectivity of the modulator changes as the air gap changes. Membrane thickness and the air gap are suitably selected to achieve zero overall modulator reflectivity in one of the two membrane positions. Equations define acceptable values for the thickness of the membrane thickness and the air gap. The membrane and air gap are formed by various etching and photolithographic methods.