A method for determining if a graded-index glass optical multimode fiber has a refractive index profile that will compensate modal dispersion with chromatic dispersion when used in an optical channel having a multimode vertical cavity surface emitting laser has at least two weighting functions. The functions are used to compute the relative mode group delays over two radial offset regions within the core of the optical fiber. The peak group delay of the of the higher-order fiber mode distribution is less than the peak group delay of the lower-order mode distribution.

The laser-induced dispensing system includes a cartridge assembly having a supply reel for supplying a foil having a light transmissive layer wound around the supply reel, and a take-up reel for taking up the foil. There is provided a coating device for coating the foil by a donor material during a motion of the foil. The laser-induced dispensing system also includes an irradiation head having optics configured for focusing a laser beam. Additionally, a controller, for controlling the cartridge assembly to establish motion of the foil, and the optics to focus the laser beam onto the foil at a location downstream of the outlet of the coating device so as to release droplets of the donor material from the foil is provided.

Example embodiments include an optical interrogation system with a sensing fiber having a single core, the single core having multiple light propagating modes. Interferometric apparatus probes the single core multimode sensing fiber over a range of predetermined wavelengths and detects measurement interferometric data associated with the multiple light propagating modes of the single core for each predetermined wavelength in the range. Data processing circuitry processes the measurement interferometric data associated with the multiple light propagating modes of the single core to determine one or more shape-sensing parameters of the sensing fiber from which the shape of the fiber in three dimensions can be determined.

An optical fiber including a core region having an outer radius r.sub.1 in a range from 4.0 μm to 8.0 μm and a relative refractive index profile Δ.sub.1 with a maximum relative refractive index Δ.sub.1max in a range from 0.20% to 0.50%, a cladding region comprising a trench cladding region having a minimum relative refractive index Δ.sub.3min greater than −0.60% and less than −0.10%, and a trench volume greater than 30%-μm.sup.2 and an outer cladding region having a relative refractive index Δ.sub.4 in a range from −0.10% to 0.10%. The optical fiber also including a primary coating and a secondary coating. The optical fiber has a mode field diameter at 1310 nm of greater than 8.8 microns, a cable cutoff wavelength of less than 1260 nm, a zero dispersion wavelength between 1300 nm and 1324 nm, and low macrobend loss at 1550 nm.

A multicore optical fiber is provided that includes a first core with silica glass doped with chlorine and/or an alkali metal, a first inner cladding surrounding the first core, and a first outer cladding surrounding the first inner cladding and having a first trench region having a volume of about 30%Δ-micron.sup.2 or greater. The multicore optical fiber also includes a second core with silica glass doped with chlorine and/or an alkali metal, a second inner cladding surrounding the second core, and a second outer cladding surrounding the second inner cladding and having a second trench region having a volume of about 30%Δ-micron.sup.2 or greater. Additionally, a common cladding surrounds the first core and the second core, and the first core and the second core each have an effective area at 1550 nm of about 100 micron.sup.2 or less.

Disclosed herein is a method for measuring temperature via distributed temperature sensing comprising transmitting light through a fiber optic cable; detecting backscattered light in the fiber optic cable, wherein the backscattered light comprises an anti-Stokes band and a Stokes band; calculating a ratio between an intensity of the anti-Stokes band and an intensity of the Stokes band; and using the calculated ratio to determine a temperature being sensed in the fiber optic cable; wherein the fiber optic cable comprises, from the center to the periphery; a central core having a refractive index that decreases progressively from a center of the central core to an edge of the core, wherein the refractive index follows an alpha profile; wherein a bandwidth-length product of the multimode optical fiber has a value greater than 2000 MHz-km at 1550 nm.

Disclosed is an illumination system for delivering incoherent radiation to a metrology sensor system. Also disclosed is an associated metrology system and method. The illumination system comprises a spatial filter system for selective spatial filtering of a beam of said incoherent radiation outside of a module housing of the metrology sensor system. At least one optical guide is provided for guiding the spatially filtered beam of incoherent radiation to the metrology sensor system, the at least one optical guide being such that the radiation guided has a substantially similar output angle as input angle.

A test apparatus has at least one optical source, a high-speed photodetector, a microcontroller or processor, and electrical circuitry to power and drive the optical source, high-speed photodetector, and microcontroller or processor. The apparatus measures the frequency response and optical path length of a multimode optical fiber under test, utilizes a reference VCSEL spatial spectral launch condition and modal-chromatic dispersion interaction data to estimate the channels total modal-chromatic bandwidth of the fiber under test, and computes and presents the estimated maximum data rate the fiber under test can support.

Provided is an optical propagation device including an optical fiber having a core and a clad having a lower refractive index than a refractive index of the core, wherein the optical fiber is any of a step index multimode optical fiber or a few-mode optical fiber, an optical signal propagates in at least two or more multiple modes in the core of the optical fiber, the optical fiber is bent such that tensile force generated by bending is discontinuously applied to two or more locations of the optical fiber across a length direction of the optical fiber, and at each bent portion of the optical fiber, stress is non-uniformly generated across an outer peripheral direction of the optical fiber.

An optical fiber includes a glass portion, a primary coating layer, and a secondary coating layer. In the optical fiber, a value of microbend loss characteristic factor F.sub.μBL_GO is 2.6 ([GPa.sup.−1.Math.μm.sup.−10.5.Math.dB/turn].Math.10.sup.−27) or less, when represented by
F.sub.μBL_GO=F.sub.μBL_G×F.sub.μBL_O
by using geometry microbend loss characteristic F.sub.μBL_G and optical microbend loss characteristic F.sub.μBL_O.