Ofs Fitel, LLC

Massachusetts Institute of Technology

Furukawa Electric North America, Inc.

Fitel USA Corporation

Furakawa Electric North America, Inc.

Ofs Fltel, LLC

Ofs Fitel Llc, a Delaware Limited Liability Company

John Michael Fini

Man Fei Yan

Thierry Franck Taunay

Poul Kristensen

Benyuan Zhu

David John DiGiovanni

Jeffrey W Nicholson

Peter Ingo Borel

Robert Scott Windeler

Yi Sun

Siddharth Ramachandran

James William Fleming

Hermann A Haus

Lars Gruner-Nielsen

Tommy Geisler

Robert L Lingle

Kazi S Abedin

Dan Peter Jakobsen

Poh-Boon Phua

Patrick C Chou

Supradeepa V S Ramakrishna

Ryan Tyler Bise

Robert Lee Lingle, Jr

Thierry F Taunay

A hollow core fiber has a cladding comprising a matrix of cells, wherein each cell comprises a hole and a wall surrounding the hole. The fiber further has a hollow core region comprising a core gap in the matrix of cells, wherein the core gap spans a plurality of cells and has a boundary defined by the interface of the core gap. The matrix of cells comprises a plurality of lattice cells, and a plurality of defect cells characterised by at least one difference in at least one property from that of the lattice cells. The cells at the core region boundary include lattice cells and defect cells that are arranged in a pattern so as to produce birefringence in a light propagating through the hollow core fiber. Further described is a technique for making the fiber.

High-birefringence hollow-core fibers and techniques for making same

In an optical fiber, a plurality of individual cores extend through a common cladding. Each individual core supports at least one local transverse spatial mode. The individual cores and surrounding cladding are structured to support propagation of plurality of desired signal-carrying modes, while suppressing undesired modes, thereby supporting the propagation of one or more spatially multiplexed signals. The core-to-core spacing of the fiber is configured to maintain an acceptably low level of mode-coupling between cores.

Multicore fiber designs for spatial multiplexing

A hollow core fiber has a cladding comprising a matrix of cells, wherein each cell comprises a hole and a wall surrounding the hole. The fiber further has a hollow core region comprising a core gap in the matrix of cells, wherein the core gap spans a plurality of cells and has a boundary defined by the interface of the core gap. The matrix of cells comprises a plurality of lattice cells, and a plurality of defect cells characterized by at least one difference in at least one property from that of the lattice cells. The cells at the core region boundary include lattice cells and defect cells that are arranged in a pattern that define two orthogonal axes of reflection symmetry, so as to produce birefringence in a light propagating through the hollow core fiber.

Described is a general strategy of bend-compensated, single-mode LMA fibers extended into a regime with higher total index contrast and where a larger gradient is used to cancel the perturbation of a tighter anticipated bend.

Single-mode, bend-compensated, large-mode-area optical fibers designed to accomodate simplified fabrication and tighter bends

Optical fiber profiles are shown in which the optical fiber has a large mode area, but is nevertheless sufficiently bend-insensitivity to comply with technical specifications for telecommunication optical fibers. The optical fibers meet two bend-loss conditions. First, they meet tight bend conditions, which reflects macro-bending due to coiling or bending of the optical fiber. Second, these optical fibers meet cable bend conditions, which reflect macro-bending conditions that are introduced as a result of cabling. By satisfying the tight bend-loss condition and then adjusting for the cable bend-loss condition, the optical fiber permits larger effective areas than normally achievable with only bend-compensation designs.

Bend compensation in telecommunications optical fibers

An optical fiber includes a core region having a longitudinal axis. At least a portion of the core region has a substantially helical shape about a helical axis. The longitudinal axis may be substantially tangential to a helical bend in the optical fiber. A cladding region surrounds the core region. The core region and cladding region may be configured to support and guide the propagation of signal light in a fundamental transverse mode in the core region in the direction of the longitudinal axis. The fiber has a bend-induced gradient in its equivalent index of refraction over the portion of the core region. The fiber has a bend-induced equivalent index of refraction. At least a portion of cladding region has a graded refractive index opposite that of the bend-induced gradient. The cladding region may be configured to have a substantially flat equivalent index in response to a helical bend of the optical fiber.

Optical fiber with distributed bend compensated filtering

A technique is described for providing compensation for the thermo-optic effect in a large-mode-area optical fiber, filter fiber, or the like. An optical fiber is provided having a refractive index profile with ambient temperature loss characteristics including a low loss for a first type of light and a high loss for a second type of light. A hot region of the fiber connected into an optical system is identified, in which a thermal index gradient is induced in the fiber. The thermal index gradient, in the absence of a compensating index gradient, would result in degradation of the fiber's ambient temperature loss characteristics. The fiber is arranged according to a layout having a position-varying bending diameter. Throughout the identified hot region, the fiber has a compensating bending diameter that induces a compensating index gradient in the fiber. Outside of the identified hot region, the fiber has an applied operating bending diameter that maintains the fiber's ambient temperature loss characteristics.

Systems and techniques for compensation for the thermo-optic effect in active optical fibers

Techniques for analyzing output modal content of optical fibers that support more than one spatial mode are disclosed. These techniques are based on spatially resolving interference between co-propagating modes and constructing a spatial beat pattern between the co-propagating modes. By doing so, these techniques provide information about the modes that propagate along the optical fiber.

Measuring modal content of multi-moded fibers

A few-moded fiber device has several discrete sections of few-moded fibers that are separated by mode converters, with each mode converter accomplishing mode conversion between one or more pairs of modes. The mode conversions can be accomplished using a sequence, such as a periodic or cyclic sequence that would cause (1) a signal wave launched with any mode to assume every other mode for one or more times; (2) the number of times the signal remains in any modal state is substantially the same; and (3) the net signal gain or loss or group delay of the input signal is substantially the same regardless of the state of input mode. A laser few-mode amplifier is provided. An optical transmission system is also provided.

Few moded fiber device employing mode conversion

A LMA, single-mode optical fiber comprises a core region, an inner cladding region surrounding the core region, and an outer cladding region surrounding the inner cladding region. The inner cladding region is configured to provide bend compensation. In one embodiment the index profile of the inner cladding region is graded with a slope of &#x3b3;n/R, where nis the refractive index of the core region, Ris the bend radius, and &#x3b3;=0.6-1.2. In addition, the inner cladding is annular and the ratio of its outer radius to its inner radius is greater than 2. In a preferred embodiment this ratio is greater than 3. The overall index profile may be symmetric or asymmetric.

Large mode area optical fibers with bend compensation

An optical fiber has two or more core regions disposed within a common cladding region. Each of the core regions is configured to guide a respective light transmission comprising at least one optical mode along the length of the fiber. The cores are arranged within the common cladding region according to a core configuration that substantially prevents crosstalk between modes of neighboring cores in the fiber, in a deployment of the fiber in which cross-coupling between neighboring cores is affected by perturbations arising in the deployed fiber.

Techniques for reducing crosstalk in multicore fibers

An optical fiber includes a core region having a longitudinal axis. A cladding region surrounds the core region. The core region and cladding region are configured to support and guide the propagation of signal light in a fundamental transverse mode in the core region in the directions of the axis. The fiber has a bend-induced gradient of its equivalent index of refraction indicative of a loss in guidance of the mode. At least a portion of cladding region has a graded index of refraction opposite the bend-induced gradient. The cladding region is configured to have a substantially flat equivalent index in response to a bend of the optical fiber.

Bend compensated filter fiber

A hollow core fiber having polarization dependent loss is provided. The hollow core fiber embedded in a cellular cladding having a plurality of cells arranged in a nominally regular cellular lattice. A pre-determined number of cells at pre-determined locations within a cellular cladding are substituted by leakage cells that differ in at least one property including a physical or a chemical property, or both. The leakage cells collectively provide a leakage path that may preferably be made polarization sensitive, such that a core mode with a particular polarization state is selectively coupled to the cladding, thereby inducing polarization dependent loss. The leakage cells may be dispersed along a symmetry axis in a radial distance longer than one or more lattice spacing away from the core. The polarization dependent loss may be controlled further by asymmetric core shapes and/or by introducing additional surface features along the core-cladding interface.

Hollow core fiber with polarization dependent loss

Embodiments of the present invention relate to a fiber design that achieves high nonlinearity, an effective index providing phase matching for an illustrative wavelength conversion process, and a low sensitivity to perturbations in fiber scaling. In one embodiment, a fiber comprises an inner core having an inner core radius and an inner core index, an outer core having an outer core radius and an outer core index, the outer core index being lower than the inner core index, an inner cladding, having an inner cladding radius and an inner cladding index, the inner cladding index being less than the outer core index, and an effective index of the fiber, the effective index being greater than the inner cladding index and less than the outer core index, wherein the fiber has a low perturbation sensitivity factor of dispersion to scaling less than about 20 ps/nm/km along the length of the fiber.

Non-linear fiber resistant to perturbations

A multicore optical fiber includes a plurality of core regions disposed within a common cladding region. Each of the plurality of core regions is configured, in combination with the common cladding region, to propagate light along a longitudinal axis of the fiber. At least two core regions are configured to inhibit resonant coupling of propagated light therebetween within a selected region of operation. At least one segment of the fiber includes a twist that is configured such that when the twisted segment is subjected to a bend having a selected radius, the twist creates a controlled change in the amount of crosstalk between the at least two core regions, compared with the amount of crosstalk between the at least two core regions when a bend having the selected radius is introduced into a non-twisted segment of the fiber.

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John Michael Fini