Abstract: An expeditious method for introducing geometric perturbations into lightguide during fabrication offers a perturbation stream of amplitude and periodicity—constant or varying—to satisfy a variety of needs.

Abstract: An expeditious method for introducing geometric perturbations into lightguide during fabrication offers a perturbation stream of amplitude and periodicity—constant or varying—to satisfy a variety of needs.

Abstract: Embodiments of the invention include an optical communications system including a multimode optical fiber having improved overfill-launch bandwidth performance without disturbing existing laser-launch bandwidth performance. The multimode optical fiber has a characteristic differential mode delay with a first portion associated with lower order modes that behaves conventionally and a second portion associated with higher order modes that deviates from conventional behavior in a way that improves overfill-launch bandwidth performance at one operating window without adversely impacting the laser-launch bandwidth performance at the same and other operating windows. Multimode optical fibers conventionally optimized for operation at 850 nm are configured in such a way that their characteristic differential mode delay, at 1300 nm, initially increases in a conventional manner and then flattens out to approximately zero at the higher order modes.

Abstract: A method and apparatus for overcoming modal noise penalties associated with multi-mode fiber optic links operating at high data rates on the order of 10 Gb/s. The method involves restricting the center launch condition of optical signals into the multi-mode fiber while permitting loose tolerances between source and fiber.

Abstract: A method is disclosed for qualifying a multimode optical fiber 150 for bandwidth performance when used with a particular laser source. The method combines the modal power distribution (MPD) excited by a particular laser source with the differential mode delay (DMD) characteristic of the fiber. The DMD of the fiber is measured by injecting test pulses into one end of the fiber and detecting the resulting output pulse(s) at the other end. The test pulses are adapted to excite only a small number of the modes supported by the fiber. The test pulses are scanned across the core of the fiber at close intervals with the output pulse(s) stored at each radial position. A weighted sum of the output pulses is formed to determine a time-domain impulse response, where the weighting used corresponds to the MPD excited by the laser source. Bandwidth is then determined by standard methods for transforming the impulse response into the frequency domain.

Abstract: Embodiments of the invention include an optical energy transmission system, method and apparatus having improved mode coupling. According to embodiments of the invention, an optical energy transmission medium such as an optical fiber includes bubbles formed therein for inducing microbending of the optical energy transmission medium, thus promoting advantageous mode coupling, which improves bandwidth potential by reducing dispersion. The bubbles are formed, e.g., in one or more buffer region layers and/or at the interface between the coating and buffer regions. The method for manufacturing the inventive optical energy transmission medium includes controllably forming one or more buffer region layers around the coated optical fiber or other transmission medium in such a way that that a desired amount of bubbles is created and maintained within one or more of the buffer region layers and/or at the interface between the coating and buffer regions.

Abstract: Embodiments of the invention include an optical energy transmission system, method and apparatus having improved mode coupling. According to embodiments of the invention, an optical energy transmission medium such as an optical fiber includes a plurality of particles formed in one or more coating region layers surrounding the cladding region and/or one or more buffer region layers surrounding the coating region for inducing microbending thereof, thus promoting advantageous mode coupling, which improves bandwidth potential by reducing dispersion. The method for manufacturing the inventive optical energy transmission medium includes forming one or more coating region layers and/or one or more buffer region layers containing particles such as fumed silica in such a way that particles are maintained within the optical energy transmission medium and form controlled perturbations along the optical fiber that enhance mode coupling to the extent that bandwidth of the optical fiber is improved.

Abstract: A multi-mode optical fiber having an improved refractive index profile is disclosed. The refractive index profile is modified from a conventional by at least one of (i) a step formed in the index profile at the boundary of the core and cladding regions, in combination with a linear correction; (ii) a ripple near the core-cladding boundary, in combination with a linear correction, with or without an index step; and (iii) an annular ridge formed in the index profile of an &agr;-profile with a center dip defect. The invention further relates to a communications system comprising the inventive fiber.