Abstract: A light energy efficient and low cost optical system for providing uniform illumination of a light valve. The light source is an extended source generally emitting a non-uniform spatial distribution of light power. The source light is focused into the entrance end of a light transmitting tunnel having reflecting interior wall surfaces and having cross sectional and length dimensions chosen to deliver, at the exit end of the tunnel, light which is substantially uniform is power distribution, over the surface area of the exit end, due multiple reflections from the tunnel walls. The exiting light is advantageously used to uniformly illuminate a light valve. The invention includes a combination of mirrors arranged about the source light to most effectively collect and direct the light.

Abstract: Optical fiber is provided with a periodically reversing spin while the fiber is pulled through a melt zone. A cooled region of the fiber downstream from the melt zone passes between a pair of opposed elements. The opposed elements are moved so that surface regions engaging the fiber move in opposite lateral directions relative to one another, thus spinning the fiber about its axis. The lateral movement of the engaged surface portions is periodically reversed to reverse the spin direction. The opposed elements may include belts or rollers, which can be tilted to orientations oblique to the longitudinal direction of the fiber.

Abstract: Disclosed is a segmented core optical waveguide fiber having low total dispersion slope and negative total dispersion over an extended wavelength window. A wavelength window of particular interest is that in the range of about 1500 nm to 1600 nm. The waveguide fibers in accordance with the invention also have cabled cut off wavelength below about 1480 nm and attenuation at 1550 nm of less than 0.22 dB/km. Mode field diameter is maintained essentially at the nominal value for dispersion shifted waveguide fiber, i.e., 7.7 &mgr;m to 8.7 &mgr;m. Embodiments having a center segment and a first and a second annular segment are discussed in detail.

Abstract: The invention is directed to a single mode optical waveguide fiber profile that provides relatively large effective area while limiting macrobend loss. The large effective area results from configuring the core of the waveguide fiber to shift propagated light power away from the waveguide center. Macrobend loss, as measured by pin array or 20 mm mandrel testing, is maintained low by means of a power-limiting index depression surrounding the central core region of the waveguide. In addition, low attenuation is achieved and cut off wavelength is controlled to provide a telecommunications operating window in the wavelength range of about 1250 nm to 1700 nm.

Abstract: Disclosed is a single mode optical waveguide fiber designated for compensating for positive dispersion in optical telecommunications systems. A key characteristic of the invention is that the novel dispersion compensating waveguide, viz., a waveguide having large negative dispersion, contains no dopants, such as fluorine, which lower the refractive index of silica. A refractive index profile design which includes a high refractive index center segment (5) surrounded by a plurality of alternating high (6, 10, 13) and low refractive index segments, provides a dispersion compensation fiber which has the optical properties required for the system to be compensated without sacrificing bend resistance, increasing splicing loss, or elevating polarization mode dispersion.

Abstract: A reduced size multiplexer/demultiplexer component is achieved by tapering of waveguide ends in any of the input, output array, or phase shifting array of waveguides. Cross talk is limited in the tapered region by requiring that each waveguide in a tapered array have a distinct propagation constant.

Abstract: A system and method for measuring stress exerted on an optical fiber including providing an optical fiber that includes a fiber optic sensor, and exposing the optical fiber and the fiber optic sensor to various stresses associated with the process by moving the optical fiber and the fiber optic sensor through the process to be measured. The system and method further includes transmitting a source light through the optical fiber as the optical fiber and the fiber optic sensor are exposed to various stresses, receiving a return light signal from the fiber optic sensor as the optical fiber and the fiber optic sensor are exposed to various stresses, and comparing the source light signal to the return light signal for determining the stress exerted on the optical fiber.

Abstract: Disclosed is a single mode optical waveguide fiber having a relatively large effective area and good bend resistance. The waveguide fiber is characterized by a segmented core having a central segment and at least one annular segment surrounding the central segment. At least one segment has a negative relative index where the reference index is taken as the minimum index of the core. The total dispersion of the fiber is positive for wavelengths above about 1500 nm, dispersion slope is typically less than about 0.08 ps/nm2-km, and induced attenuation under pin array bend testing is typically less than 5 dB/km.

Abstract: Disclosed is a single mode optical waveguide fiber having a core refractive index profile in which the profile parameters are selected to provide an attenuation minimum. A set of profiles having the same general shape and dimensions is shown to have a group of profiles contained in a sub-set which exhibit a minimum of attenuation as compared to the remaining members of the set. The members of the sub-set have been found to have the lowest effective group index, ngeff, and the lowest change in &bgr;2 under waveguide fiber bending.

Abstract: A single mode optical waveguide fiber having a segmented core designed to provide a large effective area for light transmission. The large effective area reduces waveguide fiber non-linearities. The inventive waveguide is thus suited for transmission of high power signals over long distances. Embodiments of the inventive single mode waveguide including five core segments are given. The large effective area is achieved with essentially no degradation in optical or mechanical performance of the waveguide.

Abstract: Disclosed is a method of making a photonic crystal using a combination of extruding and drawing techniques. The method is contemplated as being capable of producing both two and three dimensional crystals due to the maturity and diversity of extruding and drawing technology. The method allows the drawing of relatively large photonic crystals and is flexible enough to provide a periodic array of channels or filaments as the crystal features. After the extruding step or steps and before the step of heating and drawing, a plurality of elongated extruded bodies can be bundled and drawn as a unit.

Abstract: Disclosed is an optical waveguide fiber preform which is an assembly of one or more core rods surrounded by a plurality of clad rods. The clad rods have a central portion and a surrounding layer, in which the refractive index of the central portion is lower than that of the surrounding layer. The preform is drawn into an optical waveguide fiber that has a two component clad layer. Proper choice of the central portion and surrounding layer provide a waveguide fiber that is endlessly single mode. Alternative embodiments include fibers containing dopants that enhance fiber photosensitivity or which provide stress-induced or asymmetric-refractive-index-induced birefringence in the waveguide fiber.

Abstract: The invention provides improved methods for reducing polarization mode dispersion (PMD) in single mode fiber by spinning the fiber during the drawing process in accordance with a spin function having sufficient harmonic content to achieve low levels of PMD for commercial fibers for which the beat lengths of the fibers, including the beat lengths of different portions of the fibers, are variable and thus not readily known in advance. The spin functions of the invention take advantage of certain resonances in energy transfer between polarization modes to achieve substantial reductions in PMD for a wide range of beat lengths. Examples of suitable spin functions include frequency-modulated and amplitude-modulated sine waves.

Abstract: An athermalization attachment for countering changes in optical characteristics of an optical fiber or other temperature sensitive optical device in response to changes in temperature. According to one aspect of the invention, a curved composite beam is attached to the fiber. The beam comprises two layers of dissimilar materials. The layer on the outside radius has a coefficient of expansion greater than that of the layer on the inside radius, such that increases in temperature cause the outside layer to expand more rapidly than the inside layer, thereby decreasing the radius of curvature of the beam. The coefficients of expansion of the layers are chosen such that the beam's temperature response counters optical changes which would otherwise occur in the fiber in response to temperature changes. In another approach, one point on a low-expansion block is attached to a point along an optical fiber.

Abstract: A distributed optical amplifier for use with soliton transmission, which reduces the effects of soliton—soliton interaction by introducing an optimum excursion in the soliton intensity. A optimum operating regime is found wherein both the pulse intensity oscillations and the soliton—soliton interactions are taken into account.

Abstract: The invention is directed to circularly polarized single mode waveguide fiber and to high data rate, multiplexed transmission systems that employ this fiber. The circularly polarized waveguide fiber attenuates the non-linear effects present in such high performance transmission links. In particular, self phase modulation is attenuated by more than 30% and four wave mixing is essentially eliminated. This latter effect occurs because four wave mixing does not occur when a multiplexed link is made of a plurality of circularly polarized waveguide fibers which are arranged so that adjacent fibers have opposite circular polarization. The circularly polarized fiber enhances the non-linear effect of cross phase modulation, a feature that can be used in optical switching components associated with the transmission link. In addition, the strength of the XPM in CPF is independent of the relative polarization states of the signal and control pulses.

Abstract: A nonlinear optical loop mirror is combined with a pulse compressor. The nonlinear loop mirror receives both control pulses and data pulses and further transmits selected data pulses in accordance with relative amounts of overlap between individual control and data pulses. The pulse compressor compresses at least one of the control and data pulses for improving the transmission efficiency of the selected data pulses and reducing crosstalk with the remaining data pulses.

Abstract: A distributed sensor (10) includes a plurality of stages (24, 28, 32, 36, 40) connected in series, each stage incorporating a length of polarization maintaining fiber (12) exposed to a phenomena such as mechanical deformation or temperature to be sensed. Inter-mode couplers are provided between the sensing fibers (26, 30, 34, 38) of the various stages. The overall transfer function of the device at a plurality of wavelengths is deconvoluted to determine the birefringence of each sensing region and does monitor plural phenomena independently of one another.

Abstract: Disclosed is a single mode optical waveguide having a segmented core of at least two segments. The relative refractive index, the index profile and the radial dimensions of the core segments are selected to provide an optical waveguide fiber having properties suitable for a high performance telecommunication system operating in the wavelength window of about 1530 nm to 1570 nm. Embodiments of the invention having two, three and four segments are described.

Abstract: The invention relates to a process for treating a machined glass surface for improving the adhesive attachment of an optical fiber to this surface, characterized in that machined surface is attacked by an aqueous solution of hydrofluoric acid, then the attacked surface is treated with a bifunctional hydrolyzable silane adhesion promoter or the product of its hydrolysis and partial condensation.