According to one aspect, a few-mode amplifying fiber in a given spectral band of use is provided. The few-mode amplifying fiber comprises a cladding having a given refractive index (n.sub.0) and at least one core of refractive index and of dimensions suited to the propagation of a finite number of spatial modes in the spectral band of use of the fiber, a spatial propagation mode corresponding to a channel for transporting information. The core comprises a first solid material having a given first refractive index (n.sub.1) strictly greater than the refractive index of the cladding (n.sub.0), and, within said first material, inclusions spatially separated from one another, formed by longitudinal bars comprising a second solid material having a second refractive index (n.sub.2) strictly greater than the first refractive index (n.sub.1), at least one of said inclusions being actively doped.

An optical waveguide is configured to guide an optical beam, and the optical waveguide includes a down-taper element configured to reduce a diameter of an incoming light beam having a random polarization; a dual-core directional coupler element configured to separate the incoming light beam into a horizontally-polarized beam and a vertically-polarized beam, each beam being confined in first and second cores, respectively; and a core fan-out element configured to increase a distance between the horizontally-polarized beam and the vertically-polarized beam upon exit from the core fan-out element. Each of the down-taper element, the dual-core directional coupler element, and the core fan-out element are 3-dimensional, 3D, printed using a single material.

An optical waveguide includes a core region extending substantially along a lengthwise centerline of the optical waveguide, a first cladding region formed along a first side of the core region, and a second cladding region formed along a second side of the core region. The optical waveguide includes a first diode segment and a second diode segment that each include respective portions of the core region, the first cladding region, and the second cladding region. The second diode segment is contiguous with the first diode segment. The first diode segment forms a first diode across the optical waveguide such that a first intrinsic electric field extends across the first diode segment in a first direction, and the second diode segment forms a second diode across the optical waveguide such that a second intrinsic electric field extends across the second diode segment in a second direction opposite the first direction.

The present disclosure relates more to mode mixing optical fibers useful, for example in providing optical fiber laser outputs having a desired beam product parameter and beam profile. In one aspect, the disclosure provides a mode mixing optical fiber for delivering optical radiation having a wavelength, the mode mixing optical fiber having an input end, an output end, a centerline and a refractive index profile, the mode mixing optical fiber comprising: an innermost core, the innermost core having a refractive index profile; and a cladding disposed about the innermost core, wherein the mode mixing optical fiber has at least five modes at the wavelength, and wherein the mode mixing optical fiber is configured to distribute a fraction of the light input at its input end from its lower-order modes to its higher-order modes.

This disclosure relates to an MCF fiber being usable for short-haul O-band transmission, having a standard coating diameter in an MFD almost the same as that of a general-purpose SMF, being capable of splicing fibers without either a marker or a polarity, and including 12 cores usable for counter propagation. The MCF includes 12 cores and a common cladding, and the common cladding has an outer periphery with a circular cross-section, the 12 cores are arranged such that no adjacent relationship is established between cores each having an adjacent relationship with any core, and are arranged such that centers of the 12 cores are line symmetric with respect to an axis as a symmetry axis that intersects with the central axis and that passes through none of the centers of the 12 cores, and an arrangement of the centers of the 12 cores has rotational symmetry once.

An optical waveguide includes a core region extending substantially along a lengthwise centerline of the optical waveguide, a first cladding region formed along a first side of the core region, and a second cladding region formed along a second side of the core region. The optical waveguide includes a first diode segment and a second diode segment that each include respective portions of the core region, the first cladding region, and the second cladding region. The second diode segment is contiguous with the first diode segment. The first diode segment forms a first diode across the optical waveguide such that a first intrinsic electric field extends across the first diode segment in a first direction, and the second diode segment forms a second diode across the optical waveguide such that a second intrinsic electric field extends across the second diode segment in a second direction opposite the first direction.

Embodiments include a fiber optic probe comprising an optical fiber, and a sensor component attached to the optical fiber, the sensor component including an asymmetric microlens array imprinted on a stimuli-responsive hydrogel. Embodiments further include a method of fabricating a fiber optic probe comprising depositing a stimuli-responsive hydrogel precursor solution on a substrate mold, the substrate mold including a concave asymmetric microlens array; contacting an end of an optical fiber with the stimuli-responsive hydrogel precursor solution deposited on the substrate mold; and exposing the end of the optical fiber and the stimuli-responsive hydrogel precursor solution to light to form a stimuli-responsive hydrogel sensor imprinted with a convex asymmetric microlens array and attached to the end of the optical fiber. Embodiments further include systems comprising the fiber optic probes.

Embodiments include a fiber optic probe comprising an optical fiber, and a sensor component attached to the optical fiber, the sensor component including an asymmetric microlens array imprinted on a stimuli-responsive hydrogel. Embodiments further include a method of fabricating a fiber optic probe comprising depositing a stimuli-responsive hydrogel precursor solution on a substrate mold, the substrate mold including a concave asymmetric microlens array; contacting an end of an optical fiber with the stimuli-responsive hydrogel precursor solution deposited on the substrate mold; and exposing the end of the optical fiber and the stimuli-responsive hydrogel precursor solution to light to form a stimuli-responsive hydrogel sensor imprinted with a convex asymmetric microlens array and attached to the end of the optical fiber. Embodiments further include systems comprising the fiber optic probes.

Systems and methods described herein provide a thermally compensated waveguide structure having a thermal index profile configured to correct thermal aberrations caused by temperature gradients in a fast axis direction and/or correct other forms of distortions in an output beam generated by the waveguide structure. The waveguide structure includes a core region, one or more cladding, and one or more heat sinks. A geometry of these portions with respect to each other can provide a cold refractive index profile such that a cold refractive index value of a portion of the core region is less than a cold refractive index value of at least one of the one or more cladding regions. Responsive to thermal compensation, the cold refractive index profile is modified, through addition of a thermal index profile, to form a hot index profile having attributes including good overlap of the fundamental mode with the gain profile and mode clean-up through gain discrimination against higher order modes.

An optical fibre for an ultrafast laser endoscope including at least the following structures: a hollow core, the periphery of which has an order of symmetry of at least six when considering axes of symmetry passing through the centre of the core and through the centre of convex shapes, seen from the centre of the core, the convex shapes at least partly making up the periphery of the core; an intermediate layer of cellular structure surrounding the core; a light conducting peripheral structure surrounding the intermediate layer of cellular structure; and an outer sheath surrounding the light-conducting peripheral structure. A particular advantage of the optical fibre is that it optimizes the emission of a high-power flux associated with fluorescence collection.