Draka Comteq B.v.

Draka Comteq France

Marianne Bigot

Pierre Sillard

Denis Molin

Koen De Jongh

Louis-Anne De Montmorillon

Jean-Baptiste Trinel

A few-mode optical fiber including a core's refractive-index profile &#x394;n(r) of trapezoid-like shape. The optical core having a center part of radius Rand a transition part ranges from the radius Rto a radius R, such that R&#x3e;Rwith Rbetween 6.8 and 11.5 &#x3bc;m, said refractive-index profile being defined by a surface integral of the core index profile of between 180&#xd7;10and 270&#xd7;10&#x3bc;m; a transition slope S of between 1.7&#xd7;10and 12&#xd7;10&#x3bc;m; with &#x394;nand &#x394;nthe refractive-index difference respectively of the center part of the optical core and of the cladding part adjacent to the optical core, with respect to the outer optical cladding.

Weakly-coupled few mode optical fibers for mode division multiplexing and corresponding optical transmission system

A few mode optical fiber that includes an optical core and an optical cladding surrounding the optical core. The FMF has a step-index profile. The optical core has a core outer radius R&#x2265;7.5 &#x3bc;m and a core refractive index difference &#x394;nsuch that 14.5&#xd7;10&#x3c;&#x394;n&#x3c;24&#xd7;10. The optical cladding comprises:

Weakly coupled few-mode fibers for space-division multiplexing

A multimode optical fiber () comprises an a-profile graded index core, a trench () surrounding the core () and an intermediate cladding () between the core and the trench. Such a multimode optical fiber () has: &#x2014;A mode carrying capacity between 54 and 68 LP modes at 1060 nm, defined by a specific relationship between the numerical aperture of the core and the core radius, &#x2014;A defined relationship between trench, core and intermediate cladding parameters to achieve a high bandwidth and low bend-loss at 1060 nm, and&#x2014;A core radius between 24 and 26 &#x3bc;m, a numerical aperture between 0.190 and 0.225 and a value of a between 2.01 and 2.05 to retain compatibility with legacy fibers.

Multimode optical fiber optimized to operate around 1060 nm, and corresponding multimode optical system

An optical fiber having an optical core and an optical cladding surrounding the optical core, the optical core having a single &#x3b1; graded-index profile with &#x3b1;&#x2265;1, &#x3b1; being a non-dimensional parameter that defines the index profile shape of the optical core, and the optical core having a maximal refractive index nat its center; the optical cladding has at its outer edge a refractive index n, and comprises a region of depressed refractive index n, called a trench, with a negative refractive index difference &#x394;n=n&#x2212;nwith respect to said optical cladding, the trench having an outer radius R. The optical core and cladding are configured to support propagation of at least six spatial modes and at maximum fifty-five spatial modes at an operating wavelength &#x3bb;between, and including, 1460 nm and 1675 nm, and the optical core satisfies an ovality criterion between 0.05 and 0.3, when said ovality criterion is measured at a circumference of equal index nwithin said core, such that &#x394;n&#x2212;n&#x2212;nis less than 75% of &#x394;n=n&#x2212;n, said ovality criterion o being defined by the following equation: where a is a length of a semi-major axis of said circumference and b is a length of a semi-minor axis of said circumference.

Coupled few mode fibers, and corresponding optical link and optical system

The invention relates to a method for qualifying the actual effective modal bandwidth of a multimode optical fiber over a predetermined wavelength range, comprising the steps of: carrying out () a Dispersion Modal Delay (DMD) measurement of the multimode optical fiber at a single wavelength to obtain an actual DMD plot; generating () at least two distinct modified DMD plots from the actual DMD plot, each modified DMD plot being generated by applying to the recorded traces a temporal delay &#x394;t that increases in absolute values with the radial offset value r, each modified DMD plot being associated with a predetermined bandwidth threshold (S1; S2); for each modified DMD plot, computing () an effective modal bandwidth as a function of said modified DMD plot and comparing () the computed effective modal bandwidth (EMBc; EMBc) with the bandwidth threshold value to which the modified DMD plot is associated; () qualifying the actual effective modal bandwidth as a function of results from the comparing step.

Method for qualifying the effective modal bandwidth of a multimode fiber over a wide wavelength range from a single wavelength DMD measurement and method for selecting a high effective modal bandwidth multimode fiber from a batch of multimode fibers

A method for selecting wide-band multimode optical fibers from a single wavelength, the method comprising the following steps of, for each multimode optical fiber obtaining a first DMD plot using a measurement of DMD carried out at a first single wavelength, obtaining from the first DMD plot, a first multimode fiber specification parameter; and for each fiber: obtaining from the first DMD plot, a curve representative of a radial offset delay, called ROD curve, as a function of the radial offset value; applying a linear fit on the ROD curve for at least two radial offset value ranges; obtaining from the linear fit and for each radial offset value range, an average radial offset delay slope, called ROD slope; selecting the multimode optical fibers meeting a first predetermined specification criterion for the first multimode fiber performance parameter, and for which the at least two computed ROD slopes meet a predetermined slope criterion.

Method for selecting wide-band multimode fibers from a single wavelength characterization

A method of qualifying an effective bandwidth of a multimode optical fiber at a first wavelength &#x3bb;, using DMD data of the fiber measured a second wavelength &#x3bb;. Data representative of a Radial Offset Delay, a Radial Offset Bandwidth and a Relative Radial Coupled Power of the fiber are derived from the DMD data at the second wavelength &#x3bb;. A transformation is performed on the ROD data and ROB data at the second wavelength &#x3bb;to obtain corresponding ROD data and ROB data at the first wavelength &#x3bb;. An effective bandwidth of the fiber at the second wavelength &#x3bb;is computed using the ROD data and the ROB data at the first wavelength &#x3bb;and the {tilde over (P)}data at the second wavelength &#x3bb;.

Method of qualifying wide-band multimode fiber from single wavelength characterization using EMB extrapolation, corresponding system and computer program

Few mode optical fibers for mode division multiplexing. The Few Mode Fiber supporting 25 or 30 LP guided modes and includes a graded index core with a &#x3b1;-profile, a radius R(at 0 refractive index difference) between 21.5 and 27 &#x3bc;m and a maximum refractive index difference Dnbetween 12.5&#xd7;10and 20&#xd7;10, and an end of the &#x3b1;-profile at a radius R, with index difference Dn; a trench surrounding the core with radius Rbetween 30 and 42 &#x3bc;m and refractive index difference Dnbetween &#x2212;15.10and &#x2212;6.10, an intermediate depressed trench with a radius R, with R&#x3c;R&#x3c;Rand a refractive index difference Dn, with Dn&#x3c;Dn&#x3c;0, wherein: for |Dn&#x2212;Dn|&#x3e;=0.5&#xd7;10&#x2212;3, Min(Dn, Dn)&#x2264;&#x2212;1.5&#xd7;10&#x2212;3, and for |Dn&#x2212;Dn|&#x3c;0.5&#xd7;10&#x2212;3, Dnis between &#x2212;5&#xd7;10&#x2212;3 and &#x2212;3.5&#xd7;10&#x2212;3.

Few mode optical fibers for mode division multiplexing having intermediate trenches

Few mode optical fibers for mode division multiplexing. The Few Mode Fiber supporting 25 or 30 LP guided modes and includes a graded index core with a &#x3b1;-profile, a radius R(at 0 refractive index difference) between 23 and 27 &#x3bc;m and a maximum refractive index difference Dnbetween 14&#xb7;10and 17&#xb7;10, and an end of the &#x3b1;-profile at a radius R, with index difference Dn; a trench surrounding the core with radius Rbetween 30 and 40 &#x3bc;m and refractive index difference Dnbetween &#x2212;15&#xb7;10and &#x2212;6&#xb7;10. Such a FMF shows a specific design of the interface between the core and the cladding such that R&#x3e;R, Dnbetween &#x2212;10&#xb7;10and &#x2212;3&#xb7;10, and Dn&#x2212;Dn&#x2265;0.9&#xd7;10.

Few mode optical fibers for mode division multiplexing

Disclosed is a method of characterizing a multimode optical fiber link including a light source and two or more multimode fibers. The method includes a step of characterizing each of said multimode fibers using a measurement of the Dispersion Modal Delay (DMD) for each of said multimode fibers, and delivering, for each of said multimode fibers, at least three fiber characteristic curves as a function of a radial offset value r; a step of characterizing the light source by at least three source characteristic curves showing at least three parameters of the source as a function of a fiber radius r and obtained by a technique similar to the DMD measurement; and a step of computing an Effective Bandwidth (EB) of the link, comprising calculating a transfer function using both each of said source characteristic curves and each of said at least three fiber characteristic curves for each of said multimode fibers.

Method for characterizing performance of a multimode fiber optical link and corresponding methods for fabricating a multimode optical fiber link showing improved performance and for improving performance of a multimode optical fiber link

The invention concerns a multimode optical fiber, with an ct-profile graded-index core with an a-value between 1.96 and 2.05 and a N value defined as N=(R/&#x3bb;)(n&#x2212;n) between 7 and 52, where Ris the multimode core radius, nis the maximum index of the multimode core and nis the minimum index at the outer edge of the graded index core. According to the invention, a depressed region directly surrounds the graded/index core and satisfies the criteria: &#x2212;2.20&#x3c;Dn&#x3c;0, where Dnis the index difference of depressed region with external cladding, and 220 Ln(N)&#x2212;1100&#x3c;V&#x3c;220 Ln(N)&#x2212;865, where Vis the volume of the depressed region. Such a multimode fiber shows an increased OFL-bandwidth above 10000 Hz&#xb7;km at an operating wavelength between 950 nm and 1310 nm.

Multimode optical fiber with high bandwidth, and corresponding multimode optical system

The invention concerns a multimode optical fiber, with a graded-index core co-doped with at least fluorine F and germanium GeOand a refractive index profile with at least two &#x3b1;-values. According to the invention, the concentration of fluorine F at the core center ([F]) is between 0 and 3 wt % and the concentration of fluorine F at the core outer radius ([F]) is between 0.5 wt % and 5.5 wt %, with [F]&#x2212;[F]&#x3e;0.4 wt %. For wavelengths comprised between 850 nm and 1100 nm, said multimode optical fiber has an overfilled launch bandwidth (OFL-BW) greater than 3500 MHz&#xb7;km and a calculated effective modal bandwidth (EMBc) greater than 4700 MHz&#xb7;km over a continuous operating wavelength range greater than 150 nm.

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Paron, France

Marianne Bigot