Abstract: The invention relates to a method of aligning magnetic flakes, which includes: coating a substrate with a carrier having the flakes dispersed therein, moving the substrate in a magnetic field so as to align the flakes along force lines of the magnetic field in the absence of an effect from a solidifying means, and at least partially solidifying the carrier using a solidifying means while further moving the substrate in the magnetic field so as to secure the magnetic flakes in the carrier while the magnetic field maintains alignment of the magnetic flakes. An apparatus is provided, which has a belt for moving a substrate along a magnet assembly for aligning magnetic flakes. The apparatus also includes a solidifying means, such as a UV- or e-beam source, and a cover above a portion of the magnet assembly for protecting the flakes from the effect of the solidifying means.

Abstract: Application of a modular coaxial package design, compatible with telecommunication passive component packaging, to microchip lasers, in particular to passively Q-switched microlasers, pumped with a fiber-coupled diode, is disclosed. The number of parts is thereby reduced while providing the adequate degrees of freedom for the active or passive alignment of the optical elements within the package.

Abstract: A holographic magnetic tape comprising a hidden image pattern for protecting against skimming, alteration and counterfeiting of the data encoded in the holographic magnetic tape. The hidden image pattern in a holographic magnetic tape of a transaction card is used to determine the validity of said transaction card and the holographic magnetic tape. This relieves the clerk at the point-of-sale of visually inspecting card which is generally ineffective.

Abstract: Opaque flakes, such as pigment or bright flake used in paints and inks, have a selected shape and/or other indicia to provide a covert security feature to an object. In some embodiments the composition includes base pigment, and the opaque covert flakes match the visual characteristics of the base pigment. In another embodiment, opaque covert flakes are mixed in the carrier with base pigment at a concentration sufficient to avoid changing the appearance of the composition. In another embodiment, opaque covert flakes are mixed in a clear or tinted varnish base that can be applied over an existing security feature. Shaped opaque covert flakes are not readily detectable by causal observation, but in some embodiments are easily seen at 50× magnification. In manufacturing the flakes a sheet of embossed frames are provided having symbols or indicia within; upon removing a coating from the sheet the coating material tends to break along frame lines and the resulting flakes are substantially uniform in size.

Abstract: A metameric optical structure is disclosed having first optical structures comprising diffractive flakes having diffractive structures thereon, and a second optical structures having non-diffractive flakes which may have other special effect properties, such as color shifting. At one angle of incidence or one viewing angle, near normal. The hues match and at other angles they do not match. The diffractive flakes are preferably magnetically aligned so that the grating structures are parallel. Disclosed is also an image formed of at least a first region of diffractive flakes and a second region of non-diffractive flakes wherein the regions are adjacent one another and wherein one of the regions forms a logo, symbol or indicia that appears or disappears in dependence upon the angle of viewing.

Abstract: A fold mirror for a projection display system is designed to lessen a perceived variation in white color balance of light reflected across the mirror wherein the white light is comprised of sub-beams of orthogonal polarization states. The mirror comprises a metal reflective layer and a plurality of optically transparent layers, wherein thicknesses and materials of the optically transparent layers are such that wavelength-averaged reflectance for p-polarized incident green light varies by less than 1%, wavelength-averaged reflectance for s-polarized blue light varies by less than 1.5%, and wavelength-averaged reflectance for s-polarized red light varies by about 4% over a range of angles of incidence between 0 and 65 degrees.

Abstract: The present invention relates to the tailoring the reflectivity spectrum of a sampled-grating distributed Bragg reflector (SGDBR) by applying digital sampling theory to choose the way each reflector is sampled. The resulting mirror covers a larger wavelength span and has peaks with a larger, more uniform, coupling constant (?) than the mirrors produced using conventional approaches. The improved mirror also retains the benefits of the sample grating approach. Additionally, most of the embodiments are relatively simple to manufacture.

Abstract: The invention relates to an optical device including a passive high confinement waveguide, such as of silicon-rich silicon nitride, on an electro-optic substrate, like lithium niobate, optically coupled to a waveguide in the electro-optic substrate. A wide range of electro-optic devices are enabled by this high confinement waveguide structure, including: directional couplers, compact tap couplers, folded electro-optic devices, electro-optic modulators including ring resonators, electro-optic gratings. Further applications enabled by the present invention include hybrid passive planar lightwave circuits (PLC) integrated with electro-optically active waveguides, using the high confinement waveguide as an intermediary waveguide to transfer optical power between the passive and active components.

Abstract: Opaque color shifting strands are disclosed that have an optically variable color with a change in angle of incident light. The strands have an organic substrate and an optical interference structure on one or both sides of the organic substrate. The optical interference design can be a Fabry-Perot structure or can be optically variable ink. Plural strands can be combined to form a textile for example such as a garment label.

Abstract: Optical systems comprise one or more optical pathways including lenses that are offset with respect to each other and lenses that are offset with respect to optical fibers.

Abstract: The present invention relates to a component assembly and to a method of fabricating such a component assembly. The component assembly includes a substrate, a mount attached to the substrate, and a component attached to the mount with solder by melting the solder with light from a light source. The mount is composed of a ceramic material having properties advantageous for soldering using a light source. As a first property, the ceramic material is optically absorptive to enable the mount to be heated by the light from the light source. As a second property, the ceramic material has a first thermal conductivity at an operating temperature of the component and a second thermal conductivity at a melting point of the solder, the second thermal conductivity being at least 25% lower than the first thermal conductivity.

Abstract: A monolithically-integrated semiconductor optical transmitter that can index tune to any transmission wavelength in a given range, wherein the range is larger than that achievable by the maximum refractive index tuning allowed by the semiconductor material itself (i.e. ??/?>?n/n). In practice, this tuning range is >15 nm. The transmitter includes a Mach-Zehnder (MZ) modulator monolithically integrated with a widely tunable laser and a semiconductor optical amplifier (SOA). By using an interferometric modulation, the transmitter can dynamically control the chirp in the resulting modulated signal over the wide tuning range of the laser.

Abstract: The invention relates to fiber-optic wavelength dispersive devices incorporating a wavelength dispersive reflector that provides auto-compensation of variations of output spectral characteristic with temperature and includes a transmissive dispersion that is followed by a beam-folding reflecting surface in a double-pass configuration grating and is coupled to a wedged shaped prism.

Abstract: A multilayer thin film filter is disclosed an organic dielectric layer serving as a spacer layer in a Fabry-Perot structure. The dielectric has embossed regions of varying thicknesses wherein the thickness within a region is substantially uniform. Each different region of a different thickness produces a different color (shift). The size of one of the embossed adjacent regions is such that the color of said one region is uniform and cannot be seen by a human eye as different in color from the uniform color of an adjacent region thereto, and wherein the color within a region can be seen with magnification of at least 10:1. This serves as a covert color coding system useful as a security device.

Abstract: An optical modulator for fiberoptic telecommunications is disclosed in which the optical signal velocity in the modulator waveguide and the electrical signal velocity in the traveling wave signal electrode are purposely mismatched by a factor of up to about 4. On-chip integrated inductors and capacitors are implemented to achieve the velocity mismatch. Improved electro-optic characteristics, such as return loss and sharper cut-off bandwidth are obtained.

Abstract: Several methods are used in novel ways with newly identified and viable parameters to decrease the peak transition energies of the pseudomorphic InGaAs/GaAs heterostructures. These techniques, taken separately or in combination, suffice to permit operation of light emitting devices at wavelengths of 1.3 ?m or greater of light-emitting electro-optic devices. These methods or techniques, by example, include: (1) utilizing new superlattice structures having high In concentrations in the active region, (2) utilizing strain compensation to increase the usable layer thickness for quantum wells with appropriately high In concentrations, (3) utilizing appropriately small amounts of nitrogen (N) in the pseudomorphic InGaAsN/GaAs laser structure, and (4) use of nominal (111) oriented substrates to increase the usable layer thickness for quantum wells with appropriately high In concentrations.

Abstract: An apparatus and method for steering a beam of light using an array of tunable optical phase delay elements is presented. The sidelobes of an angular spectrum of light reflected from the array are causing an optical crosstalk. The selected sidelobes are suppressed by perturbing the phase delay pattern of the array elements. The pattern of perturbations is found by linearizing a system of equations describing dependence of the angular spectrum of the reflected light on the phase delays introduced into the wavefront of light by the elements of the array.

Abstract: Diffractive pigment flakes are selectively aligned to form an image. In one embodiment, flakes having a magnetic layer are shaped to facilitate alignment in a magnetic field. In another embodiment, the flakes include a magnetically discontinuous layer. In a particular embodiment, deposition of nickel on a diffraction grating pattern produces magnetic needles along the grating pattern that allow magnetic alignment of the resulting diffractive pigment flakes. Color scans of test samples of magnetically aligned flakes show high differentiation between illumination parallel and perpendicular to the direction of alignment of the magnetic diffractive pigment flakes. In another embodiment diffractive pigment flakes are selectively aligned by electrical fields. In other embodiments, special diffractive optical variable images are described and the method to produce them.

Abstract: The invention relates to a polarization compensating element (PCE) for a liquid crystal, e.g. liquid crystal on silicon (LCoS), display system manufactured using a linearly photo-polymerizable polymer (LPP) for orienting a photo-polymerizable liquid crystal polymer (LCP) film. To decrease the reflection, polarization conversion, and interference events in an LPP/LCP assembly the ?N birefringence value of the LCP material is minimized. Dielectric coatings are added at various locations throughout the assembly for minimizing the amount of reflection, polarization conversion, and interference effects and for suppressing spatial retardance ripples.

Abstract: A photodiode with an improved electrostatic damage threshold is disclosed. A Zener or an avalanche diode is connected in parallel to a photodiode. Both diodes are integrated into the same photodiode housing. The diodes can be mounted on a common header or onto each other. An avalanche photodiode and an avalanche diode can be fabricated on a common semiconductor substrate. A regular p-n diode connected in series, cathode-to-cathode or anode-to-anode, to a Zener diode, forms a protection circuit which, when connected in parallel to a photodiode, provides a smaller electrical capacity increase as compared to a simpler circuit consisting just of a Zener or an avalanche diode.