Abstract: The invention relates to plastic optical fiber (POF) processes and systems and involves improved non-polishing termination techniques. The techniques provide good physical and optical characteristics, i.e., smoothness, at the termination point, thereby providing lower losses than conventionally obtained. According to one embodiment, POF is cut while the fiber is under compression. According to another embodiment, the POF is notched and then pulled at a relatively high strain rate to induce fracture. The rate is such that the strain remains in the elastic region, i.e., the fiber exhibits brittle, as opposed to ductile, behavior during the strain. The brittle behavior provides a smooth termination surface, as opposed to a plastically-deformed surface.

Abstract: An improved process for extruding plastic optical fiber without the need to prepare a preform is provided. Specifically, it was discovered that conventional extrusion techniques, e.g., screw extruders, tended to introduce an undesirable amount of particulate contaminants which increased the loss of the drawn fiber. To overcome this problem, the invention substantially reduces the number of mechanical interactions that contribute to such contamination. The process of the invention does so by using fluid pressure, instead of, e.g., screw extruders, to induce polymer flow. The process also controls the flow characteristics of the polymer, or halts the flow altogether, without mechanical controls. Specifically, the temperature of the sections through which the polymer flows is controllably adjusted, such that it is possible to bring the polymer to a desired flow rate or even to a solid state to provide a plug.

Abstract: Finishing the end of a plastic optical fiber by a device having a semi-rigid or rigid base, a solvent liner for absorbing and holding a solvent, and a re-attachable pull-off cover for keeping the solvent from evaporating when not in use. To polish the end of a plastic optical fiber, the cover is peeled off, the end of the optical fiber is contacted with the solvent liner such that solvent is transferred to the end of the optical fiber, the cover may be reapplied (using a pressure sensitive adhesive integral to either the bottom of the peel-off cover or the top of the liner), the excessive solvent, if any, is removed by using an appropriate swab, and the end of the plastic optical fiber is allowed to return to its normal state. The solvent temporarily dissolves the surface layer of the end of the optical fiber. The resulting surface tension automatically polishes the end of the optical fiber.

Abstract: Finishing an end of a plastic optical fiber by ablating the end of the plastic optical fiber by utilizing an Excimer laser so that the end of the optical fiber can be used in a optical connector. A high powered ultraviolet beam of light from the laser is absorbed by the end of the fiber and ablates the first few microns of the end face of the fiber. This process removes residual cracks and fissures to flatten the end of the fiber for use in the optical connector. The optical fiber is then ready to make a low loss interface with a source, a detector, or another optical fiber.

Abstract: Fabricating graded index plastic optical fiber by diffusing a high molecular weight dopant within a step index plastic optical fiber after the step index plastic optical fiber has been drawn from a preform using a conventional draw tower in a first embodiment. Also, the step index plastic optical fiber may be fabricated by extruding one material circumferentially around another material, e.g., by use of a concentric nozzle. The dopant is diffused after the drawing or extruding of the step index plastic optical fiber by heating the plastic optical fiber to a temperature that causes a high rate of diffusion state while measuring the transmission bandwidth of the plastic optical fiber. When the predetermined specified transmission bandwidth is measured, the plastic optical fiber is immediately returned to an ambient temperature. In addition, the plastic optical fiber may be gradually heated to an equilibrium temperature that is just below the temperature required to produce the high rate of diffusion state.

Abstract: A continuous extrusion process is provided capable of producing graded index plastic optical fiber at commercially useful speeds, e.g., at least 1 m/sec for 250 &mgr;m outer diameter fiber. Moreover, it is possible to predict the refractive index profile of the fiber, prior to actual fabrication, by performing a finite element analysis using various parameters of the extrusion process. Such prediction allows one to tune the parameters of the process to obtain a desirable outcome, while avoiding the need for substantial trial and error with the extrusion equipment.

Abstract: Optical fiber and cable performance are assured by a category of UV-cured polyurethane acrylates. Low cost is the consequence of use of the polycarbonate oligomer. Good performance and long life are ascribed to other ingredients of the coatings. Dependence on the hindered phenols for antioxidant protection assures sufficient protection for these inherently stable materials without incurring fiber damage found to result from use of hindered amine antioxidants.

Abstract: Replacing costly electro-optic or fused quartz crystalline structures or molded plastic optical waveguide splitters with an optical switch comprising an array of spatial light modulators between two relatively, thick, optical glass flats. Associated with each spatial light modulator are partial holes in the optical glass flats with the partial holes being in alignment with the spatial light modulator. Using a new experimentally-developed laser technique, these holes can be drilled to a precise depth so that the distance between the ends of standard silica optical fibers inserted into opposing holes approximates the diameter of those fibers. Since the diameter of a partial hole is insignificant compared to the overall area of an optical glass flat, the physical strength of the optical glass flats is not reduced even when a number of partial holes are drilled into the optical glass flats.

Abstract: An optical coupler using round optical fibers whose ends have been formed into a predefined shape to allow greater physical packing densities in order to achieve greater uniform illumination efficiency. The interstitial space between optical fibers is greatly reduced by thermoforming the ends of round optical fibers in a mold that makes a gradual transition from a circular shape to the predefined shape to avoid optical loss. Since the change in shape is gradual, the total cross-sectional area of the fibers remains constant; and optical loss is minimal because there is no reduction in mode volume. The predefined shape may be substantially square or rectangular. The core and cladding materials of the optical fiber are carefully chosen with respect to the glass transition state temperatures of both materials because the temperature at which the materials are formed by a mold are slightly above the glass transition state of the core or cladding, whichever is higher.

Abstract: Molding optical components from a mold that is produced using the same type of optical fibers that will be interconnected by the optical components. The outer diameter of a silica optical fiber varies only by approximately .+-.1 micron and the outer surface of a silica optical fiber has an optical finish. Thus by using optical fiber to fabricate molds, molds can be produced which have the required accuracy and finish for the production of optical components. The outer coating of the optical fibers used to fabricate the mold is only removed within and in close proximity to a combination region in a splitter/combiner resulting in the capability to pigtail optical fibers attached to a splitter/combiner molded from the resulting mold.

Abstract: Molding optical components from a mold that is produced using the same type of optical fibers that will be interconnected by the optical components. The outer diameter of a silica optical fiber varies only by approximately .+-.1 micron and the outer surface of a silica optical fiber has an optical finish. Thus by using optical fiber to fabricate molds, molds can be produced which have the required accuracy and finish for the production of optical components. The outer coating of the optical fibers used to fabricate the mold is only removed within and in close proximity to a combination region in a splitter/combiner resulting in the capability to pigtail optical fibers attached to a splitter/combiner molded from the resulting mold.

Abstract: Depolarization of light by utilizing a small concentration of refractive or diffractive microparticles in an optical core of an optical coupler that is coupling light from polarized source to a polarization type optical switch such as a ferroelectric liquid crystal. The result is that light from the laser is bent slightly by either the refractive or diffractive effects of the microspheres which causes scattering; and as a consequence, the light is depolarized in a relatively short distance within the optical core before reaching the liquid crystal switch. The microparticles maybe closely matched to the index of refraction of the core material resulting in smaller deflection angles and lower reflections. In addition, these microparticles match the specific gravity of the core material such that they do not settle out of suspension while the core material is being hardened from a semi-liquid state.

Abstract: A molded polymeric resin-filled coupler comprising two low-refractive index plastic molded subassemblies. One subassembly has an optically finished mixing region, with a channel that has a V shaped lower portion. The mixing region subassembly is covered with a lid subassembly of the same material as the mixing region subassembly. During assembly, optical fibers are inserted into the mixing region subassembly which is then filled with a high index material to form a high-refractive index waveguide core region in the channel. The molded low-refractive index subassemblies provide a waveguide cladding around the high-refractive index waveguide core. Low cost is attained by utilizing optically finished metal molds to produce the subassemblies resulting in an optically finished mixing region and lid subassemblies without the need to polish each subassembly.

Abstract: An optical coupler using round optical fibers whose ends have been formed into a predefined shape to allow greater physical packing densities in order to achieve greater uniform illumination efficiency. The interstitial space between optical fibers is greatly reduced by thermoforming the ends of round optical fibers in a mold that makes a gradual transition from a circular shape to the predefined shape to avoid optical loss. Since the change in shape is gradual, the total cross-sectional area of the fibers remains constant; and optical loss is minimal becuase there is no reduction in mode volume. The predefined shape may be substantially square or rectangular. The core and cladding materials of the optical fiber are carefully chosen with respect to the glass transition state temperatures of both materials because the temperature at which the materials are formed by a mold are slightly above the glass transition state of the core or cladding, whichever is higher.

Abstract: An optical coupler having an optical core in which a small concentration of refractive microparticles has been added to a suspension material of the optical core. The result is that light from an optical source is bent slightly by the refractive effects of the microparticles and is coupled into the higher order of modes over a relatively short distance within the optical core. These microparticles are closely matched to the index of refraction of the suspension material resulting in smaller deflection angles and fewer reflections. In addition, these microparticles match the specific gravity of the suspension material such that they do not settle out of a suspension while the optical core material is being hardened from a semi-liquid state.

Abstract: Siloxane compounds formed by the reaction of a hydridosiloxane with vinylsiloxane are employed in a wide variety of uses, e.g., coatings for optical fibers and flexible layers for touch screen cathode ray tubes. These siloxane materials are substantially improved through treatment with a lower alkene such as ethylene to prevent hydrogen evolution and undesirable crosslinking.

Abstract: Various methods have been proposed for measuring the viscosity of thermosetting polymers. It has been found that these method are generally inaccurate. A test which avoids the inaccuracies of previous techniques is proposed. In this test the heated thermosetting resin is forced at a known flow rate through a runner and through a capillary tube at the end of the runner. By measuring the pressure differential across the capillary a meaningful measure of viscosity is obtained.

Abstract: Disclosed is a planar optical waveguide that is manufacturable by the compression molding or embossing of a multilayer film of polymeric material. In one embodiment, the waveguide comprises a core layer of relatively high refractive index included between cladding layers of lower refractive index. The waveguiding channels are bounded by regions where the cladding layers are in contact and from which core material has been excluded.

Abstract: An optical splitter/combiner having an adiabatic mixing region for optically interconnecting a plurality of optical fibers. The change in shape of the adiabatic mixing region is purposely gradual so as to introduce little optical loss. The shape of the adiabatic mixing region is varied so as to minimize the change in the cross-sectional area of the adiabatic mixing region. The optical splitter/combiner is fabricated by the utilizing two subassemblies which when fitted together form the adiabatic mixing region. This formed mixing region is adapted to accepting a linear array of optical fibers in one end and a single optical fiber in the other end. The core area of the optical fibers in one end is not necessarily equivalent to those of the other end but instead are sized to ensure the relatively efficient transfer of optical energy. The adiabatic mixing region is filled with resin, and the numerical apertures of the optical fibers and the resin-filled mixing region are substantially matched.

Abstract: An optical splitter having a self-contained optical source with the optical core of the splitter being substantially numerical aperture matched to the optical source and to optical fibers connected to the splitter. By matching numerical apertures, efficient transfer of optical energy is achieved between the optical source and the connected optical fibers in spite of refractive index mismatch between the optical core and the connected optical fibers. The splitter is fabricated by inserting the optical source and optical fibers into a rigid cladding structure and filling the rigid cladding structure with a polymer which after curing becomes an optical core for communicating light from the optical source to the optical fibers.