Abstract: The wideband single-sideband modulator generates single-sideband (SSB) modulation with suppressed carrier utilizing traveling-wave LiNbO3 modulators in a Sagnac loop. In the wideband single-sideband modulator, optical light from a linearly-polarized source is injected into polarization-maintaining fiber (PolMF) where it is split equally via a polarization-maintaining (PolM) directional fiber coupler, resulting in counterpropagating lightwaves in a Sagnac loop. These counterpropagating waves are &pgr;/2 out of phase due to the action of the coupler and remain so when they return to the coupler because they travel equal distances around the loop. Because the coupler is a reciprocal device, if the waves return to the coupler with equal amplitudes, they will recombine and exit the original port toward the polarized light source.

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 reflective Faraday-based optical system is formed to include a partially transmissive optical reflector so that a portion of the optical signal propagating through the system will not be reflected but instead used as an input signal to a monitoring system. The partially transmissive reflector is configured to transmit only a relatively small portion of the optical signal (about 1-10%) so that the performance of the system is not affected. The optical monitoring arrangement may comprise one or more photodetectors, optical fibers, or other optical components for capturing the transmitted signal and converting into an electrical representation that can be evaluated to monitor the power in the optical signal.

Abstract: High speed low cost billion point optical scanner using a binary optical polarization sensitive cascaded architecture network having binary switchable optical plates for scanning in one dimension(x-direction), two dimensions(x and y directions) and three dimensions(x, y and z directions). The scanner has a fast microsecond beam switching speed and low control power and realizes high space bandwidth products of up to one billion points using minimum control signals and hardware. The binary switching optical plates are modules for the x, y, and z directions. For each of the directions, each module contains an active polarization switches and passive beam steering devices. The switches can be high speed flat panel thin film polarization switches such as ferroelectric liquid crystal devices or multiple quantum well binary polarization rotation devices or nematic liquid crystal(NLC) polarization rotator devices.

Abstract: A scanning optical system having both a reading optical system and an image forming optical system is capable of using one or more components for both systems.

Abstract: Photorefractive crystals having the formula K.sub.1-y Li.sub.y Ta.sub.1-x Nb.sub.x O.sub.3 wherein x is between 0 and 1 and y is between 0.0001 and 0.15. The crystals are useful as a photorefractive material for use in optical systems. The crystals may be doped with various first transition elements and lanthanides including copper, vanadium, chromium, iron, and manganese, nickel, europium and cerium.

Abstract: An optical beam splitter separates an input beam into two exit beams which angularly diverge from each other by a continuously variable amount. The degree of angular divergence is controlled by rotating a compound cylinder composed of a half-cylinder of birefringent material and a half-cylinder of glass about their common cylindrical axis. The cylinder is placed between a pair of plano-concave sections, which match the curvature and materials of the cylinder. The ordinary refractive index of the birefringent half-cylinder section is matched to that of the isotropic glass half-cylinder, which limits the changes in exit beam angular divergence to only one of the beams. A phase compensation block preceding the birefringent plano-concave section and the compound cylinder prevents the accumulation of optical phase between the two exit beams.

Abstract: The invention provides an optical space switch device which provides variable interconnection of one- or two-dimensionally spatially multiplexed optical signals. The optical space switch device comprises a plurality of optical space switch stages stacked to form a multi-input multi-output optical space switch. Each of the optical space switch stages comprises a plurality of 2-input 2-output optical switches, each of which comprises a polarization control layer and an optical path shifting layer. The optical path shifting layer has a bypass mode in which it outputs beams of light along optical axes and an exchange mode in which it shifts beams of light by diffraction.

Abstract: The invention relates to a programmable transverse filter required for the matched filtering of signals with very wide passband. The signals to be filtered modulate one or more optical carriers (F1) in a modulator (MOD). Each carrier is distributed over several channels by a distributor (DIV). A delay creation circuit (CR1 to CRn) is provided in each channel. These channels are next summed after having been correctly delayed and assigned a coefficient characteristic of the signal to be detected.

Abstract: An electrooptic device which comprises an electrooptic material disposed on an optical axis of an optical beam. The beam is linearly polarized in advance. The electrooptic material has opposed two surfaces in parallel with the optical axis and in both sides of the optical axis. A first electrode pair which is composed of electrode films is formed on the two surfaces of the electrooptic material to perform a lens function. And a second electrode pair which is composed of electrode films is formed on the two surfaces of the electrooptic material to perform a deflection function. The first and the second pairs are disposed side by side with each other along the optical axis.

Abstract: A binary tree switching network in which the switching states are configured to switch an input signal from a selected input to an output by means of a control code set having a minimum Hamming distance (d) greater than one which eliminates cross-talk of order (d-1) and less. Such a network may be used for switching optical signals by means of optical beam deflector stages, each having a variable polarization rotator and a polarization sensitive deflector. Elimination of first order cross-talk is readily achieved by a modification stage arranged to receive a single input from the preceding stages and to pass it to the output.

Abstract: In a device for the projection of images by means of liquid crystal panels, the two orthogonal components of light are used to build the image to be projected, thus giving a significant improvement in efficiency. To this end, before going through a liquid crystal panel, the light is separated into two beams having different directions as a function of their polarization, by means of a phase separator and then, after having undergone a phase modulation by the liquid crystal panel, these two beams are recombined to build the image given by the liquid crystal panel.

Abstract: A Faraday rotator device containing (a) a Faraday rotator, (b) a wire winding encircling the Faraday rotator for changing the magnetization state of the Faraday rotator, and (c) a hollow yoke surrounding the Faraday rotator and the wire winding for forming a substantially closed magnetic circuit together with the Faraday rotator, the hollow yoke having an opening in each of front and rear walls in alignment with the Faraday rotator for permitting a light to pass through the hollow yoke and the Faraday rotator. The optical switch containing a pair of polarizers disposed on front and rear sides of the Faraday rotator device, the magnetization direction of the Faraday rotator being reversible to change the optical path. The hollow yoke is made of a soft magnetic material or a semi-hard magnetic material.