Abstract: A liquid-crystal switching element relying upon a segmented liquid-crystal polarization modulator, at least one frequency-dispersive grating and one or more polarization-dispersive elements, such as Wollaston prisms, to switch separate wavelength-divided signals among four optical paths. The switching is done complementally between the fibers of each pair, and the same switching is done for the two pairs. According to the invention, all four beams can be processed by a single set of serial optics. The invention is particularly useful as an optical interconnect between two optical fiber communications rings in which each ring includes two counter-rotating fibers. The invention advantageously uses a dielectric thin-film beam splitter for one of the polarization-dispersive elements and a Wollaston prism for the other.

Abstract: An optical matrix protection system is described. Optical signals that are cross-connected by a N×N matrix switch are routed through alternative protection paths using an optical matrix protection system. The optical matrix protection system includes a N×1 optical switch and a 1×N optical switch. An input port of the 1×N optical switch is coupled to an output port of the N×1 optical switch. Input ports of the N×1 optical switch are connected to a plurality of 1×2 optical switches, which selectively switch input optical signals to either the N×N matrix switch or to the N×1 optical switch. Output ports of the 1×N optical switch are connected to a plurality of 2×1 optical switches, which selectively switch optical signals from either the N×N matrix switch or laid the 1×N optical switch to an output line.

Abstract: A protection system for a micro electro-mechanical system (MEMS) cross-bar switch is described. Optical signals that are cross-connected by a N×N optical matrix switch are routed through alternative protection paths using protection switch elements. The protection switch elements are incorporated as part of the silicon wafer based fabricated structure that forms the N×N optical matrix. The protection switch elements enable the N×N optical matrix switch to recover from one or more failures in switch elements of the N×N optical matrix using alternative protection paths that have the same path length as the original optical path.

Abstract: A reconfigurable multiwavelength network element includes a first demultiplexer unit for demultiplexing a first multiplexed optical signal from a first optical fiber into a first plurality of optical outputs; a second demultiplexer unit for demultiplexing a second multiplexed optical signal from a second optical fiber into a second plurality of optical outputs; a first multiplexer unit having first optical inputs for receiving signals to be multiplexed together; a second multiplexer unit having second optical inputs for receiving signals to be multiplexed together; and a cross-connect unit having first and second portions, the first portion directing signals received from at least a first one of the first plurality of optical outputs and a first one of the second plurality of optical outputs to a first one of the first optical inputs and a first one of the second optical inputs, the second portion directing signals received from at least a second one of the first plurality of optical outputs and a second one

Abstract: An optical switch particularly usable as a wavelength-division add/drop multiplexer (WADM) in a multi-wavelength communication system. Four multi-wavelength beams optically coupled to the input, output, add, and drop channels are arranged in parallel in a rectangular array and are incident upon a diffraction grating. The grating operating in one direction disperses the beams into their wavelength components and operating in the other direction recombines the wavelength components into a multi-wavelength beam. A lens focuses the components of the beams having a particular wavelength upon one of an array of tiltable micro-mirrors integrated on a silicon substrate. In one position, the mirror for a particular wavelength reflects that wavelength component from the input beam back to the output beam. In a second position, that mirror reflects that wavelength component from the input beam back to the drop beam and reflects that same wavelength component from the add beam back to the output beam.

Abstract: A dispenser for space spraying an aerosol composition comprising a container for containing the aerosol composition and a metering device for space spraying a metered amount of he composition. The composition comprises active ingredient and propellant wherein the propellant is dissolved in the active ingredient. In preferred form, the composition comprises a non-aqueous solution containing 10-85% w/w active ingredient, 1-25% w/w co-solvent and 15-80% w/w propellant.

Abstract: A liquid crystal (LC) polarization modulator segment (216, 218) includes a monitoring device (220). The monitoring device (220) includes a polarized reference light source (222), located at an LC polarization monitor input, and polarized light detector (224), located at an LC polarization monitor output. If the reference light having the correct polarization is received at the detector (224), an indication of the switch state is provided. Alternatively, if the polarized detector (224) includes orthogonal polarizers (230A, 230B) provided for two separate light detectors (232A, 232B) both the desired polarization, and the opposite polarization, may be monitored to determine whether a failure exists in the segment. If the reference light is detected having the opposite polarization (instead of or in addition to the correct polarization) or no light is detected, the segment (or the monitor) is not operating correctly.

Abstract: An apparatus and method for use in an optical system. An in-line optical wavelength reference and control module (WRCM) is inserted in series with an optical fiber signal path between an input fiber and an output fiber. The WRCM includes an input lens, a multi-element grating and an output lens. The input lens couples an input optical signal from the input fiber into the multi-element grating. The multi-element grating includes low-efficiency gratings which reflect portions of the input optical signal having different predetermined characteristics to different detectors of a detector array, while transmitting the remaining portions of the input optical signal to the output lens. The output lens couples the transmitted portions of the optical signal back onto the optical signal path. The WRCM may thus be placed directly in series with an optical signal path.

Abstract: A multiplexer/demultiplexer for optical fibers is disclosed that features a reflection diffraction grating and a graded refractive index rod in a rugged, compact assembly having low insertion loss and low crosstalk.

Abstract: Apparatus for piecewise generation of grating-like patterns in photoresponsive material with a coherent the class which splits the coherent beam into two component beams. The two component beams intersect forming a parallel plane interference pattern on a section of the photoresponsive material. An arrangement which translates the beam parallel to itself forms the interference pattern in registration with the previously generated pattern on a different section of the photoresponsive material.

Abstract: A photopolymerization process is adapted for the production of various optical devices by means of a modified process which serves to increase the index change obtainable in a variable pattern of index of refraction. The process comprises the steps of flowing into place in a supporting structure a mixture of two components of differing reactivity and polarizability, partially polymerizing the mixture, writing a pattern of varying index of refraction in the partially polymerized mixture by further polymerizing it by suitable optical radiation in a corresponding pattern, and fixing the mixture against subsequent changes in polymerization. Typical components used in the process include a mixture of the monomers cyclohexyl methacrylate and N-vinylcarbazole together with benzoin methyl ether as a photosensitive initiator of polymerization, which proceeds by free radical reactions. In the limit of our technique, one of the components can have zero reactivity.

Abstract: A technique for the fabrication of integrated optical circuits is described wherein a transparent polymer film, which is doped with a polynuclear aromatic thiol having higher index of refraction than the polymer, is deposited from a liquid solution on a smooth substrate. Upon selective exposure to radiation there is a substantial reduction or elimination of the mobility and volatility of the dopant in the polymer matrix, a phenomenon known as "photolocking". The described class of dopant permits the attainment of higher resolution than previously reported, as well as the preparation of optical direction couplers having higher coupling strengths than those of the prior art.