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.sub.1/λ).sup.2(n.sub.1.sup.2−n.sub.0.sup.2) between 7 and 52, where R.sub.1 is the multimode core radius, n.sub.1 is the maximum index of the multimode core and n.sub.0 is 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: −2.20<Dn.sub.2<0, where Dn.sub.2 is the index difference of depressed region with external cladding, and 220 Ln(N)−1100<V.sub.2<220Ln(N)−865, where V.sub.2 is the volume of the depressed region. Such a multimode fiber shows an increased OFL-bandwidth above 10000 Hz.Math.km at an operating wavelength between 950 nm and 1310 nm.

Optical coupling designs are disclosed to provide a photonic device, for example, that includes a substrate; an optical waveguide formed on the substrate and configured as a multimode waveguide to support light in different optical waveguide modes; and an optical fiber structured as a multimode fiber to support light in different optical fiber modes, the optical fiber located above the optical waveguide and optically coupled to the optical waveguide via evanescent coupling to allow light to be coupled between the optical fiber and the optical waveguide.

An optical coupling system includes a tapered coupling element having a first end opposite a second end, a core having a core diameter that is larger at the first end than at the second end, and a cladding layer that is coupled to and circumscribes the core. An optical pathway is disposed within the core and that extends between the first end and the second end. The tapered coupling element is tapered from the first end to the second end such that the core diameter adiabatically transitions a light beam traveling along the optical pathway from a first beam size at the first end to a second beam size at the second end.

An optical fiber including a multimode core having a radius, R.sub.1, and a maximum relative refractive index, Δ.sub.1MAX, at a wavelength λ.sub.0, an inner clad layer surrounding the core and having a radial thickness, T.sub.2, and a minimum relative refractive index, Δ.sub.2MIN, of about 0.0% at a wavelength of λ.sub.0, an intermediate clad layer surrounding the inner clad layer and having a radial thickness, T.sub.3, and a maximum relative refractive index Δ.sub.3MAX and an outer clad layer surrounding the inner clad layer and having a radial thickness, T.sub.4, and a maximum relative refractive index, Δ.sub.4MIN, at a wavelength of λ.sub.0. The optical fiber satisfies the following relationship: Δ.sub.1MAX>Δ.sub.3MAX>Δ.sub.2MIN, and the optical fiber exhibits an overfilled bandwidth of greater than or equal to about 1.5 GHz-km at λ.sub.0.

An optical fiber connector includes a coupler having a waveguide section integrally formed with a fiber attachment section. At least one waveguide is disposed in the waveguide section and has a core dimension that is greater at the end of the waveguide at the fiber attachment section. The fiber attachment section has a first surface and at least one recess formed on the first surface for aligning one or more optical fibers with the at least one waveguide. In an optical fiber component, an optical substrate has a first end and a second end, and at least one waveguide input at the first end and at least one waveguide output at the second end. An integral input portion of the substrate at the first end has one or more input optical fiber alignment elements and an integral output portion of the substrate at the second end has one or more output optical fiber alignment elements. One or more input optical fibers are positioned in the one or more input optical fiber alignment elements. One or more output optical fibers positioned in the one or more output optical fiber alignment elements.

The invention concerns a multimode optical fiber, with a graded-index core co-doped with at least fluorine F and germanium GeO.sub.2 and a refractive index profile with at least two α-values. According to the invention, the concentration of fluorine F at the core center ([F].sub.r=0) is between 0 and 3 wt % and the concentration of fluorine F at the core outer radius ([F].sub.r=α) is between 0.5 wt % and 5.5 wt %, with [F].sub.r=α−[F].sub.r=0>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.Math.km and a calculated effective modal bandwidth (EMBc) greater than 4700 MHz.Math.km over a continuous operating wavelength range greater than 150 nm.

An apparatus includes an optical transmitter having a plurality of optical data modulators and an end-face coupler. Each of the optical data modulators is configured to output a corresponding data-modulated optical carrier. The optical end-face coupler is configured to direct the data-modulated optical carriers into a pattern of light beams to illuminate an end-face of a multi-mode optical fiber with a pattern of light spots. The optical end-face coupler is configured to cause each of the data-modulated optical carriers to excite a set of orthonormal optical propagating modes of the multi-mode optical fiber. Some of the orthonormal optical propagating modes of the set have nontrivially differing intensity and/or phase profiles.

Disclosed is an optical fiber arrangement for inducing coupling among propagation modes of light, said arrangement comprising a multimode optical fiber (30) having an input end (32) for receiving light and an output end (31) for emitting light, with a coupling inducing section (33) extending from said input end to said output end, and a holder (80) on which the optical fiber is arranged, wherein said multimode optical fiber has a non-circular cross section. Disclosed also is a system for measuring the absorption or determining the concentration of a substance, said system comprising at least one optical fiber arrangement.

A method is used to select a multimode fiber meeting requirements of a first minimum bandwidth at a first wavelength and a second minimum bandwidth at a second wavelength different from the first wavelength. Differential mode delay (DMD) data is measured for the multimode fiber at the first wavelength. The DMD data comprises output laser pulse data as a function of the radial position of an input laser pulse having the first wavelength. The DMD data is transformed into mode group space, to obtain relative mode group delay data as a function of mode group. The multimode fiber is selected based on meeting requirements of the first minimum bandwidth at the first wavelength based on a first set of criteria, comprising a first criterion using as input the measured differential mode delay (DMD) data for the multimode fiber measured at the first wavelength. The multimode fiber is selected based on meeting requirements of the second minimum bandwidth at the second wavelength based on a second set of criteria, comprising: a second criterion using as input the relative mode group delay data. A related system is also described.

An optical fiber comprises a glass fiber including a core and a cladding surrounding the core, a non-strippable resin layer that adheres to and covers a surface of the glass fiber, and a buffer layer that covers the non-strippable resin layer, when pullout force measurement in which a length of 10 mm of each of the glass fiber and the non-strippable resin layer is pulled out at a tensile speed of 5 mm/min from the buffer layer is performed, a pullout force at 23° C. is 1.0 kg or less and a pullout force at 95° C. is 0.50 kg or less.