Ofs Fitel, LLC

Robert L Lingle

David W Peckham

Lars Gruner-Nielsen

Yi Sun

Man Fei Yan

John Michael Fini

James William Fleming

Tristan Kremp

Jinkee Kim

Durgesh Vaidya

Roman Shubochkin

Alan H McCurdy

Kasyapa Balemarthy

Torger Tokle

A system of aligning concatenated sections of multicore optical fiber incorporates the capability of intentionally changing core assignments as part of the azimuthal alignment process. The intentional changing of core assignments, referred to as offset clocking, compensates for differences in properties of the individual core regions in a way that reduces variations between the spatial channels supported in the transmission system. The offset clocking technique can be used, e.g., to improve the attenuation (or other selected properties of the propagating signals). The offset clocking technique may be used to step through sequential changes core assignments at one or more splice locations (passive clocking) or identify a particular pairing of cores from one fiber section to the next (e.g., 'good quality' core assigned to a “poor quality” signal exiting the first section) and rotate the fiber sections with respect to each other to achieve this particular core assignment.

Methods and apparatus for aligning and splicing optical fibers

Described is a technique for the design and manufacture of MMFs. Designs are implemented so as to limit the maximum variation in z(r, &#x3bb;) with respect to wavelength, where z(r, &#x3bb;) is the dielectric constant weighted by the square of the wavelength. MMFs for use in CWDM applications are specifically described.

Manufacture of multi-mode optical fibers

A few-mode fiber is described, having a graded-index core and a surrounding cladding comprising a ledge between the core and the trench, a down-doped trench abutting the ledge, and an undoped cladding region abutting the trench. The fiber's refractive index profile is configured to support 9 or more LP modes for transmission of a spatially-multiplexed optical signal. Undesired modes have respective effective indices that are close to, or less than, the cladding index so as to result in leakage of the undesired modes into the outer cladding. The index spacing between the desired mode having the lowest effective index and the leaky mode with the highest effective index is sufficiently large so as to substantially prevent coupling therebetween.

Multiple LP-mode fiber designs for mode-division multiplexing

A few-mode optical fiber comprises a core surrounded by a cladding, having a step index profile that is structured to support propagation of a plurality of desired signal-carrying modes, while suppressing undesired modes. The core and cladding are configured such that the undesired modes have respective effective indices that are close to, or less than, the cladding index such that the undesired modes are leaky modes. The index spacing between the desired mode having the lowest effective index and the leaky mode with the highest effective index is sufficiently large so as to substantially prevent coupling therebetween.

Step-index few-mode fiber designs for spatial multiplexing

Certain embodiments of the invention may include optimized trench-assisted ultra large area (ULA) optical fibers. According to an example embodiment of the invention, a trench-assisted optical fiber, optimized for microbend frontier (MBF) performance is provided. The optical fiber includes a core region having a longitudinal axis, a shelf region surrounding said core region, a cladding region surrounding said shelf region, said core and shelf and cladding regions configured to support and guide the propagation of signal light in a fundamental transverse mode in said core and shelf regions in the direction of said axis. The optical fiber further includes a core effective area (Aeff) of between 135 &#x3bc;mand about 170 &#x3bc;m; a relative effective index difference (Neff) of greater than about 0.08%; a loss at 1550 nm of less than 0.180 dB/km; and a microbend frontier (MBF) distance of less than about 90%.

Optimized ultra large area optical fibers

The specification describes modified step index and GRaded INdex (GRIN) fibers with low core relative delta (near 0.8%) which have desirable properties for transmission. These lower delta fibers have lower attenuation losses due to reduced Rayleigh scattering, which is desirable to improve performance in multiple mode multiplexing. The fiber designs include optimized raised triangle profiles, and depressed cladding profiles, to support two and four LP modes.

Multiple LP mode fiber designs for mode division multiplexing

Certain embodiments of the invention may include optimized trench-assisted ultra large area (ULA) optical fibers. According to an example embodiment of the invention, a trench-assisted optical fiber, optimized for figure-of-merit (FOM) performance, is provided. The optical fiber includes a core region having a longitudinal axis, a shelf region surrounding said core region, a cladding region surrounding said shelf region, said core and shelf and cladding regions configured to support and guide the propagation of signal light in a fundamental transverse mode in said core and shelf regions in the direction of said axis. The optical fiber further includes a core effective area (Aeff) of between 135 &#x3bc;mand about 170 &#x3bc;m; and an index profile having a figure of merit (FOM) frontier distance less than about 0.7 dB.

Certain embodiments of the invention may include optimized trench-assisted ultra large area (ULA) optical fibers. According to an example embodiment of the invention, a trench-assisted optical fiber, optimized for microbending and figure-of-merit (FOM) performance is provided. The optical fiber includes a core region having a longitudinal axis, a shelf region surrounding said core region, a cladding region surrounding said shelf region, said core and shelf and cladding regions configured to support and guide the propagation of signal light in a fundamental transverse mode in said core and shelf regions in the direction of said axis, the cladding region including an inner trench and an outer trench. The optical fiber further includes a core effective area (Aeff) of between 135 &#x3bc;mand about 170 &#x3bc;m; a figure of merit (FOM) frontier distance less than about 0.8 dB; and a microbend frontier (MBF) distance of less than about 90%.

Certain embodiments of the invention may include optimized trench-assisted ultra large area (ULA) optical fibers. According to an example embodiment of the invention, a trench-assisted optical fiber, optimized for figure-of-merit (FOM) performance is provided. The optical fiber includes a core region having a longitudinal axis, a shelf region surrounding said core region, a cladding region surrounding said shelf region, said core and shelf and cladding regions configured to support and guide the propagation of signal light in a fundamental transverse mode in said core and shelf regions in the direction of said axis. The optical fiber further includes a core effective area (Aeff) of between 135 &#x3bc;mand about 170 &#x3bc;m; a relative effective index difference (Neff) of greater than about 0.08%; a loss at 1550 nm of less than 0.185 dB/km; and an index profile having a figure of merit (FOM) frontier distance less than about 0.5 dB.

Described is a modular method of making an optical fiber comprising a core and a cladding configured to support and guide a fundamental transverse mode, the cladding including (i) an outer cladding having an index nless than the index nof the core, (ii) an inner cladding having an index n&#x3c;n, (iii) a pedestal having an index n&#x2248;n, (iv) an inner trench disposed between the inner cladding and the pedestal, the inner trench having an index n&#x3c;&#x3c;n, and (iv) an outer trench disposed between the pedestal and the outer cladding, the outer trench having an index n&#x3c;nand relatively close to n. To suppress unwanted HOMs the pedestal is configured to resonantly couple at least one unwanted transverse mode of the core (other than the fundamental mode) to at least one transverse mode of the pedestal.

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Johns Creek, GA, United States of America

Robert L Lingle