Abstract: Polymer techniques are used to reduce the feature size in electrical or mechanical processes. A first embodiment uses a light sensitive polymer. A first illumination forms a lens structure. A second illumination is focused by that lens structure to form a final feature. The lens can then be removed. A second embodiment uses holographic techniques to pattern polymers and form consistent pores within the polymers.

Abstract: A wavelength selective optical fiber coupler having various applications in the field of optical communications is disclosed. The coupler is composed of dissimilar waveguides in close proximity. A light induced, permanent index of refraction grating is recorded in the coupler waist The grating filters and transfers energy within a particular range of wavelengths from a first waveguide to a second waveguide. Transversely asymmetric gratings provide an efficient means of energy transfer. The coupler can be used to combine or multiplex a plurality of lasers operating at slightly different wavelengths into a single fiber. Other embodiments such as a dispersion compensator and gain flattening filter are disclosed.

Abstract: Devices and techniques for processing an analog signal by using optical pulses at a high sampling rate. Parallel analog-to-digital conversion channels can be implemented to achieve high-speed analog-to-digital conversion.

Abstract: A polymer material is exposed to radiation of a type that changes some aspect of the polymer's radiation passing properties. The radiation that caused the property change is then contained by the material. The property change can be self-focusing or self-trapping light can be used. In that case, the same light that causes the photopolymerization is contained by the change in index of refraction that is caused by the polymerization.

Abstract: A lens is formed out of semiconductor material. The semiconductor produces light which is coupled to the lens. The lens focuses the light and also minimizes refractive reflection. The lens is formed by a graded aluminum alloy, which is oxidized in a lateral direction. The oxidation changes the effective shape of the device according to the grading.

Abstract: Optical waveguide devices based on optical coupling of different modes by using a mediating mode. Such waveguide devices generally have at least two coupling regions. The first coupling region couples an output mode and the mediating mode, and the second one couples the mediating mode and an input mode that copropagates with the output mode. Under proper conditions, the energy in the input mode can be completely transferred to the output mode, without energy loss to the mediating mode.

Abstract: An optical wave power control device and method enables signal control, such as modulation transferring and switching, to be effected with the application of very low power to a controller which is in optical communication with a recirculating mode resonator and an optical propagation element. The propagation element is configured such that is in power communication with a high Q volumetric resonator. Power of a chosen resonant wavelength is coupled into said resonator, where it circulates with very low loss and returns energy to the propagation element. By introducing a control signal into the controller, the propagated power can be varied between substantially full and substantially zero amplitudes. Loss factors can be maintained such that said resonator is overcoupled, i.e. parasitic losses are less than coupling losses, and a critical coupling condition exists in which a small swing in the controller causes a disproportionate change in the optical output signal.

Abstract: A device and technique to sample an analog signal by optical pulses at a high sampling rate. Parallel analog-to-digital conversion channels can be implemented to achieve high-speed analog-to-digital conversion.

Abstract: A lens is formed out of semiconductor material. The semiconductor produces light which is coupled to the lens. The lens focuses the light and also minimizes refractive reflection. The lens is formed by a graded aluminum alloy, which is oxidized in a lateral direction. The oxidation changes the effective shape of the device according to the grading.

Abstract: Using the wavelength selectivity and low loss characteristics of optical couplers, in which index of refraction gratings in a non-evanescent waveguide merged region reflect only a selected wavelength band, signal switching and control systems of novel characteristics are provided for multi-wavelength optical communication systems. In a router, for example, selected wavelengths or wavelength bands on an add/drop line can be added to or dropped from a main fiber, by cross switching between wavelength selective loops disposed sequentially in the lines. In a collector box, as another example, selected wavelength bundles can be routed from one fiber onto multiple fibers. In a bandpass filter a selected wavelength band is transmitted with low loss while those wavelengths outside the selected wavelength band are rejected with very high loss.

Abstract: A semiconductor light-emitting device having an optical cavity with a fiber grating. A vertical-cavity-surface-emitting laser can be constructed to produce single-mode tunable laser oscillation and signal wavelength conversion.

Abstract: A semiconductor light-emitting device having one or more depletion regions that are controlled by one or more control electrodes to vary the spatial distribution of the carriers in an active layer. The voltages on the control electrodes can be controlled to modulate the current density in the active layer and the output light intensity. The polarization of a surface emitting diode laser based on this device can be controlled or modulated.

Abstract: A method of designing phase shifting masks with improved resolution. Auxiliary transmissive phase regions with properly selected locations and dimensions are introduced to eliminate unwanted interference patterns. A usual opaque region between the transmissive features that are phase-conflicting to one another is partially or entirely replaced with a transmissive region of an opposite phase with respect to the phase of the transmissive features. In positive photoresist layouts, the light-absorbing features are partially or entirely made transmissive while an opposite and uniform phase is maintained throughout the transmissive background. Segmenting features with at least one auxiliary phase region and adjusting attenuation of different features can further improve the performance.

Abstract: Wavelength selective devices and subsystems having various applications in the field of optical communications are disclosed. These devices and subsystems are composed of bi-directional grating assisted mode couplers. The high add/drop efficiency and low loss of this coupler enable low loss wavelength selective elements such as optical switches, amplifiers, routers, and sources to be fabricated. The grating assisted mode coupler can be wavelength tuned by modifying the optical properties of the coupler interaction region. A programmable, wavelength selective router composed of multiple grating assisted mode couplers is also disclosed.

Abstract: An optical switch for programmable spatial and spectral filtering of wavelength-multiplexed optical signals of different wavelengths. Multiple input and output waveguides are connected to a waveguide filter to allow adiabatic propagative evolution of an optical wave therebetween. A plurality of electrically-controlled diffraction gratings are formed in the waveguide filter to provide mode coupling between different optical modes. Each grating can be controlled electrically to achieve efficient power conversion between two different modes in the waveguide filter. Different modes can be directed to different output waveguides, thereby achieving programmable switching and signal modulation.

Abstract: A wavelength selective optical fiber coupler having various applications in the field of optical communications is disclosed. The coupler is composed of dissimilar waveguides in close proximity. A light induced, permanent index of refraction grating is recorded in the coupler waist. The grating filters and transfers energy within a particular range of wavelengths from a first waveguide to a second waveguide. Transversely asymmetric gratings provide an efficient means of energy transfer. The coupler can be used to combine or multiplex a plurality of lasers operating at slightly different wavelengths into a single fiber. Other embodiments such as a dispersion compensator and gain flattening filter are disclosed.

Abstract: Substantial improvements in photorefractive device lifetimes are provided by control of electron migration which results in the decay of gratings in photorefractive materials due to diffusion and other effects. A new class of photorefractive devices using compensating electronic and ionic gratings having relatively low efficiency but nonetheless usable gratings is provided by arranging the gratings to be reflective in a wavelength band outside the photo-excitation band of the photorefractive material, as by using an infrared operating wavelength. Longer lifetimes in high efficiency gratings are achieved by constant or periodic illumination of photorefractive materials to assure uniform charged distribution of electrons and maintenance of the ionic backbone grating.

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: A median circuit operates over a single-clock-cycle to determine the median of the group. Each value is compared with a plurality of other values. One of those other values become the eventual median. The possible median which is closest to all of the elements being compared is taken as the overall closest value and established as the median. Most specifically, this is done by applying the higher voltage of the pair to one end of a capacitor at the same time as a precharge. After the precharge is complete, the lower voltage of the pair is applied to the capacitor. The capacitor acts as a charge pump, lowering its other end by an amount proportional to the distance between the higher voltage of the pair and the lower voltage of the pair. A plurality of the capacitors are connected together, so that the output from the group of cells represents the average capacitors among all elements. The highest group represents the eventual median.

Abstract: A laser utilizes feedback from a volume holographic grating used as a wavelength standard to lock the laser output wavelength to its desired value. This feedback can be non-optical, wherein the holographic filter output is used to actively control the wavelength through an external control mechanism. This feedback can also be optical, wherein a volume hologram reflection grating is used to generate optical feedback into the laser gain.