Abstract: A method of selecting a multimode optical fiber includes determining a first modal bandwidth value BW for each of a plurality of multimode optical fibers in a straight position and determining a second modal bandwidth value bBW for each of a plurality of multimode optical fibers in a bent position. Typically, the method includes selecting the multimode optical fibers for which the second modal bandwidth value bBW is greater than a threshold bandwidth A. The threshold bandwidth A may be (i) a function of the multimode optical fiber's first modal bandwidth value BW and a bending-loss value BL and (ii) greater than the multimode optical fiber's first modal bandwidth value BW.

Abstract: A depressed graded-index multimode optical fiber includes a central core, an inner depressed cladding, a depressed trench, an outer depressed cladding, and an outer cladding. The central core has an alpha-index profile. The depressed claddings limit the impact of leaky modes on optical-fiber performance characteristics (e.g., bandwidth, core size, and/or numerical aperture).

Abstract: A multimode optical fiber includes a central core having a radius (r1) and an alpha-index profile. The multimode optical fiber further includes a depressed trench, which surrounds the central core, that has a width (wt) and a refractive index difference (?nt) with an outer optical cladding. Typically, the central core's diameter is between about 47 and 53 microns, and the depressed trench's width (wt) is between 0.5 micron and 2 microns. The depressed trench's refractive index difference (?nt) with the outer optical cladding is typically between ?4×10?3 and ?1×10?3.

Abstract: A single-mode optical fiber includes a central core, an intermediate cladding, a buried trench, and optical cladding. The central core has an outer radius r1 and a refractive index difference ?n1 relative to the optical cladding. The intermediate cladding has an outer radius r2 and a refractive index difference ?n2 relative to the optical cladding. The buried trench has an outer radius r3 and a refractive index difference ?n3 relative to the optical cladding. The optical fiber typically has an effective area of about 150 ?m2 or greater at a wavelength of 1550 nanometers and exhibits low bending losses.

Abstract: An optical transmission fiber comprises a central core having an index difference ?n1 with an outer optical cladding; a first inner cladding having an index difference ?n2 with the outer cladding; and a second buried inner cladding having an index difference ?n3 with the outer cladding of less than ?3·10?3. The second buried inner cladding moreover contains Germanium in a weight concentration of between 0.5% and 7%. The fiber shows reduced bending and microbending losses while exhibiting the optical performances of a standard single-mode fiber (SSMF).

Abstract: A single-mode optical fiber includes a central core surrounded by an outer cladding. The optical fiber includes at least first and second depressed claddings positioned between the central core and the outer cladding. The central core typically has a radius of between about 3.5 microns and 5.5 microns and a refractive-index difference with the outer cladding of between about ?1×10?3 and 3×10?3. The first depressed cladding typically has an outer radius of between about 9 microns and 15 microns and a refractive-index difference with the outer cladding of between about ?5.5×10?3 and ?2.5×10?3. The second depressed cladding typically has an outer radius of between about 38 microns and 42 microns and a refractive-index difference with the first depressed cladding of between about ?0.5×10?3 and 0.5×10?3.

Abstract: A single-mode optical fiber includes a central core surrounded by an outer optical cladding. The optical fiber includes an inner depressed cladding, a ring, and an outer depressed cladding positioned between the central core and the outer optical cladding. The central core typically has a refractive-index difference (Dn1) with the outer optical cladding of between about ?0.5×10?3 and 0.5×10?3. The ring typically has an inner radius (rring1) of between about 21 microns and 35 microns and a refractive-index difference with the outer optical cladding (Dnring) of between about ?0.5×10?3 and 0.5×10?3. The outer depressed cladding typically has a volume (Vout) of between about 15 ?m2 and 30 ?m2. The ratio of the volume of the central core over the width of the ring (Vcore/wring) is typically between about 0.12 micron and 0.2 micron.

Abstract: A multimode optical fiber comprises a central core having an alpha profile, a depressed cladding having a portion in continuity with the alpha profile of the central core and a stepped portion, and an outer cladding. The alpha profile is obtained by co-doping at least two dopants. A multimode fiber for Ethernet optical system with an improved bandwidth is thus obtained.

Abstract: A non-zero dispersion shifted optical fiber (NZDSF) includes a central core, an inner cladding, and an outer cladding. The central core has an outer radius r1 and a maximum refractive index difference Dn1 with respect to the outer cladding. The inner cladding includes a first intermediate cladding and a buried trench. The first intermediate cladding has an outer radius r2 and a refractive index difference Dn2 with respect to the outer cladding. The buried trench has an outer radius r3, a width w3, and a negative refractive index difference Dn3 with respect to the outer cladding. In some embodiments, the inner cladding includes a second intermediate cladding having an outer radius r4 and a refractive index difference Dn4 with respect to the outer cladding. For a radius of curvature of 30 millimeters at a wavelength of 1625 nanometers, the optical fiber typically exhibits bending losses of about 0.5 dB/100 turns or less.

Abstract: The present invention embraces an optical fiber that includes a central core having an alpha refractive index profile with respect to an outer optical cladding. The optical fiber also includes an inner cladding and a buried trench. The central core includes a core matrix doped with at least fluorine and a dopant element that increases refractive index. The optical fiber typically has reduced bending losses and cladding effect as well as a high bandwidth at the wavelengths of 850 nanometers and 1300 nanometers for high-data-rate applications.

Abstract: A multimode optical fiber includes a central core surrounded by an outer cladding. The central core has a graded-index profile with respect to the outer cladding and an outer radius r1 of between about 22 microns and 28 microns. The optical fiber also includes an inner cladding positioned between the central core and the outer cladding, and a depressed trench positioned between the inner cladding and the outer cladding. The multimode optical fiber exhibits reduced bending losses.

Abstract: Disclosed is an optical system including a polychromatic optical source emitting multiple transverse modes, an optical link having at least one portion of multimode optical fiber, and an optical device positioned between the optical source and the input of the multimode optical fiber. The optical device can modify the distribution of the energy coupling of the transverse modes emitted by the source in the propagation modes of the multimode optical fiber. The optical system makes it possible to use low-cost transverse multimode optical sources for producing high-bandwidth Ethernet transmission networks having excellent performance.

Abstract: A hybrid optical fiber integrates features of multimode optical fibers and single-mode optical fibers. The hybrid optical fiber possesses an optical core having a first core region and a second core region to provide improved optical mode coupling ratio for single-mode transmission while maintaining a broad bandwidth for multimode transmission. The hybrid optical fiber's optical core may optionally include a depressed trench positioned between the optical core's first core region and the optical core's second core region to reduce modal dispersion and to improve modal bandwidth during multimode transmissions.

Abstract: A multimode optical fiber includes a central core, an inner cladding, a buried trench, and an outer cladding (e.g., an outer optical cladding). Typically, the optical fiber's central core is a glass-based central core having an alpha-index profile (i.e., a graded-index profile), an outer radius r1, and a maximum refractive index difference ?n1 with respect to the outer cladding. The central core's alpha-index profile has a minimum refractive index at the central core's outer radius r1 that corresponds to a refractive index difference ?nend with respect to the outer cladding. The inner cladding has an outer radius r2, a width w2, and a refractive index difference ?n2 with respect to the outer cladding. The buried trench has an outer radius rext, a width w3, and a refractive index difference ?n3 with respect to the outer cladding. The multimode optical fiber typically has reduced bending losses, a high bandwidth at wavelengths of both 850 nanometers and 1300 nanometers, and a reduced cladding effect.

Abstract: The present invention embraces a multimode optical fiber that includes a central core having an alpha refractive index profile with respect to an outer optical cladding and a depressed trench positioned between the central core and the outer optical cladding. The central core's refractive index at its periphery is the same as the outer cladding's refractive index. Typically, an inner cladding is positioned between the central core and the depressed trench. The optical fiber achieves reduced bending losses without significantly increasing numerical aperture.

Abstract: An optical fiber includes a central core, which has a radius r1 and a refractive index n1, and a surrounding optical cladding, which has a refractive index n2 such that n2<n1 and 0.31%<((n1?n2)÷n2)<0.55%. The optical cladding has at least five holes. These holes, which are positioned between about 9 microns and 17 microns from the central core, have a radius rh such that 0.5r1?rh?r1.

Abstract: An optical fiber having a core and an outer cladding, the core including from its center outward a central core having a radius and a refractive index difference with respect to the outer cladding, and a depressed inner cladding. The depressed inner cladding includes at least a first portion having a radius and a refractive index difference with respect to the outer cladding, the first portion preferably being adjacent to the central core, and a second portion adjacent to the first portion constituting a depressed trench having a radius, and a refractive index difference with respect to the outer cladding. The first portion of the inner cladding has a refractive index below the refractive index of the outer cladding, and the depressed trench has a refractive index that is lower than the refractive index of the first portion of the depressed inner cladding.

Abstract: The present invention embraces an optical fiber that includes a central core having an alpha-index profile with respect to an outer cladding, a first depressed trench, an inner cladding, a second depressed trench, and an outer cladding (e.g., an outer optical cladding). The second depressed trench's volume is typically greater than the first depressed trench's volume. The optical fiber achieves reduced bending losses and a high bandwidth with a reduced cladding effect for high-data rate applications.

Abstract: A method of classifying a graded-index multimode optical fiber includes taking a series of individual measurements at a single wavelength, and using the measurements to characterize the departure of the multimode optical fiber's actual index profile from the corresponding nominal index profile. The measurements, coupled with intermodal dispersion or EMB measurement, may be used to predict the approximate transmission properties of the optical fiber at wavelengths other than the measurement wavelength. It is desirable for a graded-index multimode optical fiber to possess, at a wavelength of 850 nanometers, a radial offset bandwidth of at least 6000 MHz·km for all radial offsets between 0 and about 70 percent of the radius of the optical fiber's core.

Abstract: A method of assessing the power penalty at a given bit error rate of a multimode fiber including measuring a set of elementary fiber responses corresponding to different offset launches of light over the core radius into the multimode fiber, generating a global fiber response by applying, to the set of elementary fiber responses, a set of weighting coefficients and delays depending on the different offset launches of the elementary fiber responses, and computing a parameter representative of a fiber power penalty from the global fiber response, wherein the set of weighting coefficients includes several subsets of weighting coefficients time delayed relative to one another, wherein at least one relative time delay is not set to zero, and wherein weighting coefficients of each subset depend on the different offset launches of the elementary fiber responses.