Ofs Fitel, LLC

Fitel USA Corporation

Furukawa Electric North America, Inc.

Cornell University

University of Aarhus

Ofs Fitel Llc, a Delaware Limited Liability Company

Gruner-nielsen, Lars

Olsen, Jorgen Ostgaard

Lars Gruner-Nielsen

Dan Peter Jakobsen

Poul Kristensen

David W Peckham

Robert L Lingle

Quang Nghi Trong Le

William Alfred Reed

Chris Xu

Yi Sun

Kim G Jespersen

Tommy Geisler

Bera Palsdottir

Stig Nissen Knudsen

Martin E V Pedersen

Bent Edvold

Ji Cheng

Marie Wandel

David John DiGiovanni

Man Fei Yan

John Michael Fini

Torben Erik Veng

Martin Erland Vestergaard Pedersen

Jorgen Ostgaard Olsen

Alan H McCurdy

Morten Ostergaard Pedersen

Soren Herstrom

Peter Gaarde

Susanne Dyrbol

Lene V Jorgensen

Torger Tokle

Chunhui Xu

Dan P Jakoben

Martin Ev Pedersen

Peter Balling

Juha-Matti Savolainen

A distributed Brillouin sensor system comprising a pump laser, and a combined fiber assembly including at least a first optical fiber section and a second optical fiber section is described. The pump laser is arranged so as to send a pump signal into a first end of combined fiber assembly, and the detector system is arranged to detect Brillouin backscattering from the combined fiber assembly. The combined fiber assembly is characterized by the first section having a low Brillouin gain, and the second fiber section having a high Brillouin gain.

Distributed brillouin sensor

A distributed Brillouin sensor system comprising a pump laser, a Brillouin sensor fiber, and a detector system is described. The pump laser is arranged so as to send a pump signal into a first end of the Brillouin sensor fiber, and the detector system is arranged to detect Brillouin backscattering from the Brillouin sensor fiber. The Brillouin sensor fiber is characterized by having a negative dispersion, and further by an effective area of the sensor fiber being less than or equal to 50 &#x3bc;m.

Distributed Brillouin sensor

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

Embodiments of the present invention generally relate to fiber designs for wavelength tunable ultra-short pulse lasers. More specifically, embodiments of the present invention relate to systems incorporating fiber designs for higher order mode fibers capable of soliton self frequency shifting where a system comprises a first fiber for shifting the wavelength from a pump wavelength to a transfer wavelength and a second fiber for shifting the pulse from the transfer wavelength to an output wavelength. In one embodiment of the present invention, a wavelength tunable short pulse fiber laser system comprises: a pulse generator for providing a pulse having an input wavelength; a mode-converter; a first designed fiber for shifting the pulse from the input wavelength to a transfer wavelength; and a second designed fiber for shifting the pulse from the transfer wavelength to an output wavelength.

Fiber designs for wavelength tunable ultra-short pulse lasers

Embodiments of the present invention generally relate to optical mode conversion by nonlinear effects. More specifically, embodiments of the present invention relate to nonlinear mode conversion utilizing intermodal four-wave mixing to convert light between modes having different wavelengths for complex applications. In one embodiment of the present invention, a fiber comprises an input end for receiving light in a first mode at a first wavelength, and an output end for outputting light in a desired second mode at a desired second wavelength, wherein the first wavelength and the second wavelength are not the same. In many embodiments, the fiber comprises a higher-order mode fiber.

Optical mode conversion by nonlinear effects

A highly nonlinear optical fiber having an improved stimulated Brillouin scattering threshold is provided. The fiber includes a central core region made substantially from silica doped with aluminum, a trench region surrounding the central core region, and a silica cladding surrounding the trench region. The refractive index profile of the fiber is optimized. A refractive index difference of the central core region relative to the cladding (&#x394;n+) is less than 26&#xd7;10, and more preferably at or near 21&#xd7;10. A refractive index difference of the trench region relative to the cladding (&#x394;n&#x2212;) is less than &#x2212;5&#xd7;10. The trench region is preferably doped with fluorine. The aluminum doping level of the central core region is preferably less than 14 wt % Al. A fiber doped with aluminum having this refractive index profile exhibits a significantly higher figure of merit (P&#x3b3;L) than conventional germanium-doped fibers.

Highly nonlinear optical fiber with improved SBS threshold and moderate attenuation

Embodiments of the present invention are generally related to embodiments of the present invention relate to a fiber stretchers module for use in the 1550 nm wavelength range. In one embodiment of the present invention, a fiber stretcher module for use in the 1550 nm wavelength range comprises a fiber having a relative dispersion slope, RDS, and a relative dispersion curvature, RDC, wherein a ratio of said slope to said curvature is between about 30 nm and about 0 nm, having a dispersion value of less than about &#x2212;10 ps/(nm&#xb7;km) at about 1550 nm, and a RDS is equal to or greater than 0.

Fiber stretcher module for use in the 1550 nm wavelength range

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

A dispersion-compensating system and a dispersion-compensating fiber have an improved figure of merit and effective area. The dispersion-compensating system comprises a bulk dispersion-compensating module for providing optical-domain bulk dispersion compensation for an optical signal transmission. Additionally, the system may further comprise residual dispersion compensation, which can be performed in the electrical domain following coherent detection of both amplitude and phase of an optical signal. The dispersion-compensating fiber comprises an up-doped core region; a down-doped trench; an up-doped ring; and an outer cladding, and is configured to have a high figure of merit (FOM).

Dispersion-compensating system and dispersion-compensating fiber with improved figure of merit

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

Embodiments of the present invention are generally related to embodiments of the present invention relate to a fiber stretchers module for use in the 1550 nm wavelength range. In one embodiment of the present invention, a fiber stretcher module for use in the 1550 nm wavelength range comprises a first fiber comprising a relative dispersion curve value of greater than about 0.0002 nmand a dispersion value of less than about &#x2212;60 ps/(nm&#xb7;km) at about 1550 nm, and a second fiber comprising a relative dispersion curve value of about zero and a relative dispersion slope value of about 0.003 nmat about 1550 nm, wherein the fiber stretcher module comprises a collective relative dispersion slope of about 0.0413 nmand a relative dispersion curve of about 0.00286 nmat 1550 nm.

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

A stretcher fiber has a core region, inner trench region, ring region, outer trench region, and outer cladding region. The fiber regions are structured to provide the stretcher fiber with a relationship between dispersion and wavelength, such that the second and third derivatives of the stretcher fiber's propagation constant with respect to angular frequency have a shape and wavelength range matching those of a selected compressor module.

Stretcher fiber and module

A stretcher fiber includes a core region, inner trench region, ring region, outer trench region, and outer cladding region. The core region has a radius r, a refractive index n, and a positive effective refractive index &#x394;nwith respect to an outer cladding region having an outer radius rand a refractive index n, where &#x394;nis equal to n&#x2212;n. The inner trench region surrounds the core region and has an outer radius r, a refractive index nless than n, and a negative effective refractive index &#x394;nequal to n&#x2212;n. The ring region surrounds the trench region and has an outer radius r, a refractive index ngreater than n, and a positive effective refractive index &#x394;nequal to n&#x2212;n. The outer trench region surrounds the ring region and has an outer radius r, a refractive index nless than n, and a negative effective refractive index &#x394;nequal to n&#x2212;n. The outer cladding region surrounds the outer trench region. The values of r, r, r, r, r, &#x394;n, &#x394;n, &#x394;n, and &#x394;ncause the fiber to have a negative dispersion and to have a relative dispersion slope greater than 0.005 nmat a specific wavelength within a selected operating wavelength band. Additionally, the stretcher may be used in combination with a second fiber to match the dispersion and RDS of a selected grating compressor.

A pumped Raman fiber optic amplifier includes two optical fibers whose lengths are determined so that the fibers exhibit dispersions of substantially equal magnitude and opposite sign at the wavelength of an input light signal. The fiber having the positive dispersion has a cylindrical core, an outer cladding, and a refractive index profile with respect to the outer cladding. The core has a diameter of between 3 and 6 microns (&mgr;m) and a difference (&Dgr;n) between the index of the core and the cladding is between 0.015 and 0.035. The index profile includes a trench region adjacent the circumference of the core, and the trench region has a width of between 1 and 4 &mgr;m and a &Dgr;n of between &minus;0.005 and &minus;0.015. The two fibers are slope matched so that the net dispersion of the amplifier remains substantially zero over a broad wavelength interval.

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Lars Gruner-Nielsen