Abstract: Disclosed is a fiber optic module containing one or more optical fibers having an attenuator formed in the output end of the fibers to filter out unwanted higher order modes. The optical fibers are typically gain fibers or dispersion compensating fibers, and the attenuator consists of a coil, or a series of bends, of sufficient number and bend radius that higher order modes are reduced below a desired level.

Abstract: A method for screening fiber polarization mode dispersion using a polarization optical time domain reflectometer. A pulse radiation is emitted into the fiber under test, and the backscattered radiation is measured by the POTDR and used to obtain a POTDR trace. The POTDR trace is then analyzed to compare the variation of signals along the length of the fiber, the variation in signals relating to the level of PMD along the length of the fiber. Because high levels of PMD correspond to localized levels of low variability, by setting the variability of signal threshold sufficiently low, fibers having unacceptably high localized PMD can be identified and removed.

Abstract: Optical fibers are coated with a clay-polymer nanocomposite composition comprising optionally a hydrophobic layered silicate dispersed in a radiation curable resin preferably on a molecular level. The radiation curable resin may contain a mixture of a radiation curable oligomer and a diluent(s). The coating when cured has improved tensile properties, and when used as an outer primary coating exhibits low microbending sensitivity.

Abstract: An optical apparatus comprises a dispersion compensating optical waveguide, and an optical pump that pumps the dispersion compensating optical waveguide with light. The light from the pump provides suitable selective gain to a fundamental mode of the dispersion compensating optical waveguide that multi-path interference is substantially reduced.

Abstract: A gain medium for use in optical amplifiers or laser oscillators is disclosed. The gain medium includes a transition-metal doped glass-ceramic material having a crystal phase and a glass phase. The crystal phase is formed in situ in the glass phase, with the transition metal ions preferentially partitioning into the crystals from the glass phase. The crystals so formed have a size of less than 50 nm, and the transition metal ions within them are capable of lasing at a wavelength within the range of about 900 to 3000 nm. Also disclosed are amplifier and laser oscillator configurations, where the glass-ceramic gain medium is applied in a variety of configurations. Also disclosed is a method of amplifying a signal of light wherein the glass-ceramic gain medium is pumped with light energy so as to excite the transition metal ions, and the signal of light is transmitted through the gain medium while the transition metal ions are excited, whereby the signal of light is amplified.

Abstract: A two dimensional matrix of marks indicating match or mismatch of one or more search arguments with the value of data elements accessed from a field common with all records of a database file. The matrix of marks created after one pass through all the records of the file is searched for a specified pattern which identifies records where the data element values, as between successive records, have a certain sequence as specified by the search arguments.