Abstract:
Multimode optical fiber systems with adjustable chromatic modal dispersion compensation are disclosed, wherein the system includes a VCSEL light source and primary and secondary optically coupled multimode optical fibers. Because the VCSEL light source has a wavelength spectrum that radially varies, its use with the primary multimode optical fiber creates chromatic modal dispersion that reduces bandwidth. The compensating multimode optical fiber is designed to have a difference in alpha parameter relative to the primary multimode optical fiber of -0.1
Abstract:
A method for making low PMD fiber comprising the steps of: (i) making an initial fiber preform; (ii) modifying said initial fiber preform to introduce higher birefringence than that of the initial fiber preform into modified preform; and (iii) drawing an optical fiber from the modified preform and bi-directionally spinning the drawn fiber during draw.
Abstract:
Microstructured optical fiber for single-moded transmission of optical signals, the optical fiber including a core region (170) and a cladding region (180), the cladding region including an annular void-containing region (184) that contains non-periodically disposed voids. The optical fiber provides single mode transmission and low bend loss.
Abstract:
An optical fiber comprising a core having a refractive index profile and a centerline; and a cladding layer surrounding and directly adjacent the core; wherein core includes updoping material and is doped with Aluminum in at least one region of the core, such that either: (a) the average longitudinal acoustic wave velocity within the core is within 0.05% of the longitudinal acoustic wave velocity within the cladding; or (b) the longitudinal acoustic wave velocity in the core changes by at least 0.2%.
Abstract:
A method for producing low-PMD fiber, in which a glass fiber is drawn from an optical fiber perform by a tractor which pulls such optical fiber from said perform; subsequent to said tractor pulling the fiber is twisted about its axis to increase the magnitude of twist which is imparted to said fiber. The fiber is then wound onto a fiber storage spool such that at least a portion of the twist imparted to said optical fiber is retained while said fiber is wound on said spool.
Abstract:
The present invention provides devices and methods for dispersion compensation. According to one embodiment of the invention, a dispersion compensating device includes a negative dispersion fiber having an input configured to receive the optical signal, the negative dispersion fiber having a length and dispersion sufficient to remove any positive chirp from each wavelength channel of the optical signal, thereby outputting a negatively chirped optical signal; an amplifying device configured to amplify the negatively chirped optical signal; and a nonlinear positive dispersion fiber configured to receive the negatively chirped optical signal. The devices of the present invention provide broadband compensation for a systems having a wide range of variable residual dispersions.
Abstract:
The present invention is directed to a protection switch (10) for use in a node of a two-fiber optical shared protection ring. The two-fiber optical shared protection ring propagates at least one bi-directional channel. The switch includes an N x N optical switch fabric system disposed in the node. The N x N optical switch fabric (20) includes 2N input/output (I/O) ports, wherein N is four, or an integer multiple of four. Each optical switch fabric (20) is configured to switch at least one bi-directional channel. At least N three-port optical devices (40, 42, 46, 48, 50, 52, 54) are coupled to N of the I/O ports. Each three-port optical device (40, 42, 46, 48, 50, 52, 54) includes a bi-directional port coupled to an I/O port. The bi-directional port is configured to propagate the at least one bi-directional channel.
Abstract:
A wavelength selective optical cross-connect includes a first demultiplexor feeding into individually removable modules that in turn feed a first multiplexor, such that the cross-connect is expandable and repairable on a wavelength or waveband basis. The modules desirably include multiple optical components in the optical path, with components in each module matched to others in that module to provide module-to-module variation below that of the variation in module components. The modules desirably include an additional demultiplexor and multiplexor. The modules also desirably include wavelength or narrowband amplification together with power equalization. The modules may also include a switch fabric. Alternatively, the switch fabric may be provided in the form of a separate removable switch module or modules, with various technologies employed in various switch modules, including manual switching with automatic connection discovery, with simple plug-in upgradeability to modules having automatic or remotely actuated switching.
Abstract:
A single mode optical waveguide fiber having a relatively large effective area and a low dispersion slope has a segmented core having a central segment, a first annular segment, and a second annular segment. Each segment has a relative refractive index percent, and an inner and outer radius. The relative refractive index percent and the radii of each core segment are chosen from the following ranges: the relative index of the central segment within the range of about 0.53 % to about 0.9 %; the relative index of the first annular segment within the range of about -0.2 % to about 0.15 %; the relative index of the second annular segment within the range of about 0.1 % to about 0.4 %; the outer radius of the central segment within the range of about 3.1 ñm and about 5.0 ñm; and the center radius of the third annular segment within the range of about 6.18 ñm and about 7.7 ñm.
Abstract:
An optical fiber with low attenuation is provided. The fiber is produced under conditions that reduce fictive temperature. Processing includes maintaining the fiber at temperatures at or near the glass transition temperature (Tg) for an extended period of time. For silica-based fibers, the preferred temperatures are temperatures between 1000 °C and 1700 °C. The extended residence times are achieved in a continuous fiber manufacturing process by increasing the path length of the fiber through a processing region maintained at temperatures between 1000 °C and 1700 °C. The increased path length is achieved by including one or more fluid bearing devices in the processing region. The extended residence time in the processing region allows the structure of the glass fiber to relax more completely and to more closely approach the equilibrium state. The more relaxed glass structure leads to a lower fictive temperature and provides fibers with lower attenuation.