Abstract: A three-dimensional optical switch using three-dimensional rewritable waveguides in a photosensitive substrate. At least two light beams are used to illuminate the substrate in the region where the waveguide is to be written. The refractive index of the substrate changes at the points where the beams intersect. Therefore, the light beams can be directed to create a three-dimensional waveguide in the photosensitive substrate. A plurality of inlet ports in one surface of the substrate are thereby connected to a plurality of outlet ports on another surface of the substrate. Alternatively, the inlet ports and the outlet ports may be on the same surface of the substrate. The invention also provides methods of creating waveguides in photosensitive media using the device described herein.

Abstract: An external cavity laser includes an optical gain medium in the cavity of the external cavity laser. The optical gain medium is capable of emitting light over a range of wavelengths. The external cavity laser further includes a diffractive focusing element including a central radial portion and a peripheral radial portion. The central radial portion has a dispersivity less than a threshold, and the peripheral radial portion has a dispersivity greater than the threshold. The diffractive focusing element is operable to diffractively focus the light back into the optical gain medium at differing wavelength-dependent focal distances. The external cavity laser further includes means for confining the diffractive focusing of the light to the peripheral radial portion of the diffractive focusing element. In various embodiments, the means for confining includes a central obscuration and/or a radial offset of the diffractive focusing element.

Abstract: A system for accurately aligning a plurality of optical elements includes a wafer into which are formed a plurality of holes. The holes are formed into an array and are each designed to accept an optical element. After each optical element is located and inserted into a respective hole, the optical elements are polished to be planar with the surface of the wafer. The optical elements may include fibers and lenses. The system may also include a wafer containing optical fibers optically aligned with a wafer containing lenses. The optical fibers direct light into corresponding lenses, which collimate and launch the light into an optical switch.

Abstract: An optical switch, optical switching method, and a switched optical communication system include at least one micro-mirror in a path along which an optical signal propagates between first and second optical waveguides. Further provided is a refractive material through which the optical signal propagates. The refractive material has a refractive index greater than the refractive index of air. The refractive index of the refractive index may be less than or equal to a refractive index of the optical waveguides.

Abstract: A liquid crystal micro display (lcmd) is manufactured by creating a hole in an lcmd surface, filling the lcmd with liquid crystal material through the hole, and then sealing the hole. The invention allows an lcmd to be tested before it is separated from other lcmds and packaged. As a result, the invention increases the yield and reduces the cost associated with lcmd manufacturing.

Abstract: An optical switching assembly comprised of a substrate, a first plurality of waveguides in a first plane in the substrate, a second plurality of waveguides in a second plane parallel to said first plane in the substrate, the optical signals being selectively transferable from one substrate to the other. The second waveguides cross the first waveguides at an angle and the first waveguides each have a segment extending generally parallel to a segment of the second waveguides at the crossing. Controllable coupling material is disposed between the segments of the waveguides at the crossing and a control circuit is employed for selectively changing the index of refraction of the coupling material by electrical or thermal means.

Abstract: A tunable Fabry-Perot filter, which includes a pair of opposed partially reflective surfaces, a cavity between the partially reflective surfaces, a nano-dispersion of liquid crystals disposed in the cavity, and a control unit for applying an electric field to the liquid crystals.

Abstract: The frequency-selective optical multiplexer comprises, an LC polarization controller, a spectral demux/mux and input/output optics including two ports, a first optical path spatially separated from a second optical path and polarization-dispersive optics. The polarization dispersive optics are disposed between the ports and the optical paths; generate from an optical signal a pair of polarization components, composed of a first polarization component and a second polarization component having orthogonal polarizations; and output the first and second polarization components via the first and second optical paths, respectively. The first and second polarization components have first and second polarizations when the optical signal is received at one port, and have the second and the first polarizations, respectively, when the optical signal is received at the other port.

Abstract: A three-dimensional optical switch using three-dimensional rewritable waveguides in a photosensitive substrate. At least two light beams are used to illuminate the substrate in the region where the waveguide is to be written. The refractive index of the substrate changes at the points where the beams intersect. Therefore, the light beams can be directed to create a three-dimensional waveguide in the photosensitive substrate. A plurality of inlet ports in one surface of the substrate are thereby connected to a plurality of outlet ports on another surface of the substrate. Alternatively, the inlet ports and the outlet ports may be on the same surface of the substrate. The invention also provides methods of creating waveguides in photosensitive media using the device described herein.

Abstract: A liquid crystal display device including a polyimide alignment layer, having a bistable liquid crystal material and a polymer stabilizer in an amount effective to stabilize the liquid crystal the liquid crystal preferably having a low or medium pretilt angle to eliminate undesired states and stripe tendency and to increase hysteresis. The device has a low driving voltage, low power consumption and fast switching.

Abstract: An optical device for planar lightwave circuits and a method of making the same provide a waveguide with a core having a cylindrical shape and a more circular than rectangular cross section that is viewed perpendicular to an optical path formed by the optical waveguide. The optical device comprises a planar substrate having a peripheral index of refraction and the waveguide formed in the substrate. The waveguide has a core index of refraction that is greater than the peripheral index of refraction. The method of making the optical waveguide in a planar substrate comprises forming the waveguide core within the substrate such that the waveguide core has an index of refraction within the cross section that is higher than an index of refraction in a cladding region. The cladding region of the substrate surrounds the core. Furthermore, the core cross section can vary along its length to provide an optical mode transformer.

Abstract: A system for accurately aligning a plurality of optical elements includes a wafer into which are formed a plurality of holes. The holes are formed into an array and are each designed to accept an optical element. After each optical element is located and inserted into a respective hole, the optical elements are polished to be planar with the surface of the wafer. The optical elements may include fibers and lenses. The system may also include a wafer containing optical fibers optically aligned with a wafer containing lenses. The optical fibers direct light into corresponding lenses, which collimate and launch the light into an optical switch.

Abstract: In a 3D MEMS optical switch titling mirrors are actively aligned to minimize losses in optical power. In one embodiment the optical signals in the output fibers are tapped and detected and the sensed outputs are used by a control circuit with a feedback loop that adjusts the alignment signals sent to the MEMS actuators. In a second embodiment, an emitter which is either a single LED or laser diode is optically coupled to the output fibers for injecting alignment beams back into the fibers. The alignment beams have a frequency bandwidth outside that of the information beams. The alignment beams are detected at the input fibers via directional optical couplers and the sensed outputs are used by a control circuit with a feedback loop to adjust the alignment signals. The alignment signals are dithered and their phase and amplitude shifts are used to generate the appropriate feedback signals.

Abstract: An optical fiber apparatus and method of aligning a singlemode optical fiber reduce problems associated with power loss due to misalignment of the fiber at an interface. The method comprises providing an optical fiber with an expanded core portion that terminates in an interface end and aligning the interface end of the expanded core portion to an optical component. The optical fiber apparatus has an expanded core portion that has an expanded core radius at an interface end of the optical fiber. The expanded core may be incorporated into the entire length of the optical fiber or in a transition section of a fiber that also comprises a basic core portion having a basic core radius. Both the expanded and basic core radius support only a single optical mode for propagating a signal.

Abstract: An optical switching assembly comprised of a substrate, a first plurality of waveguides in a first plane in the substrate, a second plurality of waveguides in a second plane parallel to said first plane in the substrate, the optical signals being selectively transferable from one substrate to the other. The second waveguides cross the first waveguides at an angle and the first waveguides each have a segment extending generally parallel to a segment of the second waveguides at the crossing. Controllable coupling material is disposed between the segments of the waveguides at the crossing and a control circuit is employed for selectively changing the index of refraction of the coupling material by electrical or thermal means.

Abstract: A tunable Fabry-Perot filter, which includes a pair of opposed partially reflective surfaces, a cavity between the partially reflective surfaces, a nano-dispersion of liquid crystals disposed in the cavity, and a control unit for applying an electric field to the liquid crystals.

Abstract: In a 3D MEMS optical switch titling mirrors are actively aligned to minimize losses in optical power. In one embodiment the optical signals in the output fibers are tapped and detected and the sensed outputs are used by a control circuit with a feedback loop that adjusts the alignment signals sent to the MEMS actuators. In a second embodiment, an emitter which is either a single LED or laser diode is optically coupled to the output fibers for injecting alignment beams back into the fibers. The alignment beams have a frequency bandwidth outside that of the information beams. The alignment beams are detected at the input fibers via directional optical couplers and the sensed outputs are used by a control circuit with a feedback loop to adjust the alignment signals. The alignment signals are dithered and their phase and amplitude shifts are used to generate the appropriate feedback signals.

Abstract: A liquid crystal micro display (lcmd) is manufactured by creating a hole in an lcmd surface, filling the lcmd with liquid crystal material through the hole, and then sealing the hole. The invention allows an lcmd to be tested before it is separated from other lcmds and packaged. As a result, the invention increases the yield and reduces the cost associated with lcmd manufacturing.

Abstract: A micro display system is provided that uses ambient light to illuminate the microdisplay. A wave-guide contains an embedded dye which absorbs ambient light through the surface of the wave-guide and re-emits light. Total internal reflection in the wave-guide and reflection from a reflector at one end of the wave-guide direct all the re-emitted light through a light-transmissive end to an illuminator for illuminating the microdisplay with polarized light. The microdisplay has a plurality of pixels which are activated to selectively reflect polarized or rotated polarized light back through the illuminator where the polarized light forms an image for a user.