The methods disclosed herein include forming an expanded core in an optical fiber with a glass core having a core dopant and a core outer surface, and a glass cladding immediately surrounding the core and having a flat glass-portion surface closest to the core outer surface at a first core spacing S1. The methods include applying heat to a section of the optical fiber to cause the glass core to expand toward the flat glass-portion surface due to thermal diffusion of the core dopant. The methods also include terminating the application of heat to define the expanded core in the heated section of the optical fiber. The expanded core defines an evanescent coupling region having a second core spacing 0≤S2<S1 and an adiabatic transition region between the core and the evanescent coupling region of the expanded core.

In some examples, a microstructured fiber comprises a cladding material surrounding at least one core material, wherein the at least one core material comprises an array of discrete devices contacted in parallel. A method of producing a microstructured fiber may include 3D-printing a fiber preform, thermally drawing the fiber preform into a fiber that preserves the cross-sectional geometry of the fiber preform, and axially patterning the fiber into a microstructured fiber comprising an array of discrete devices contacted in parallel. In some embodiments, microstructured fibers may be integrated into a sensory textile that includes at least one of an electrooptic portion, a sonar portion, a magnetic gradiometer portion, and a piezogenerating portion. In some embodiments, microstructured fibers may be formed into an in-fiber integrated quantum device circuit or an in-fiber ion trap.

An optical fiber sensor extends coaxially with a controllable heater to provide high-resolution axial measurement of thermal properties such as thermal convection of the surrounding, Heat removal by either conduction or convection may be used to deduce material height in a tank, or velocity of flow when coupled with localized heating, or other aspects of the material based on thermal conductivity.

An optical fiber sensor extends coaxially with a controllable heater to provide high-resolution axial measurement of thermal properties such as thermal convection of the surrounding, Heat removal by either conduction or convection may be used to deduce material height in a tank, or velocity of flow when coupled with localized heating, or other aspects of the material based on thermal conductivity.

Methods, devices, and systems for welding optical fibers and perforated elements by pulsed laser beam are provided. In one aspect, a method includes focusing a pulsed laser beam onto a region of a joining surface formed by an outer circumference of an optical fiber and an inner circumference of a hole of a perforated element, a beam direction of the pulsed laser beam running in an axial direction of the joining surface, and moving a laser focus of the pulsed laser beam in the region axially in or counter to the beam direction to produce at least one weld seam in the region. The optical fiber and the perforated element are locally melted in the region by the pulsed laser beam focused into a material of the optical fiber and a material of the perforated element and are thereby welded to one another.

Methods, devices, and systems for welding optical fibers and perforated elements by pulsed laser beam are provided. In one aspect, a method includes focusing a pulsed laser beam onto a region of a joining surface formed by an outer circumference of an optical fiber and an inner circumference of a hole of a perforated element, a beam direction of the pulsed laser beam running in an axial direction of the joining surface, and moving a laser focus of the pulsed laser beam in the region axially in or counter to the beam direction to produce at least one weld seam in the region. The optical fiber and the perforated element are locally melted in the region by the pulsed laser beam focused into a material of the optical fiber and a material of the perforated element and are thereby welded to one another.

A method for fabricating a beam shaper array assembly, where the beam shaper array assembly changes the shape of a plurality of beams. The method includes providing an optical endcap having a plurality of connector stems, welding a fiber to each of the stems to form an emitter array and positioning a beam shaper array adjacent to the endcap opposite to the stems. The method also includes measuring an angle error and a position error of each fiber, calculating a correction for each fiber for the angle error and the position error and correcting the angle and position of each fiber using the calculated corrections.

A method for fabricating a beam shaper array assembly, where the beam shaper array assembly changes the shape of a plurality of beams. The method includes providing an optical endcap having a plurality of connector stems, welding a fiber to each of the stems to form an emitter array and positioning a beam shaper array adjacent to the endcap opposite to the stems. The method also includes measuring an angle error and a position error of each fiber, calculating a correction for each fiber for the angle error and the position error and correcting the angle and position of each fiber using the calculated corrections.

Optical components and methods of manufacture thereof. A first optical component has a hollow-core photonic crystal fiber includes internal capillaries for guiding radiation and an outer capillary sheathing the internal capillaries; and at least an output end section having a larger inner cross-sectional dimension over at least a portion of the output end section than an inner cross-sectional dimension of the outer capillary along a central portion of the hollow-core photonic crystal fiber prior to the output end section. A second optical component includes a hollow-core photonic crystal fiber and a sleeve arrangement.

Optical components and methods of manufacture thereof. A first optical component has a hollow-core photonic crystal fiber includes internal capillaries for guiding radiation and an outer capillary sheathing the internal capillaries; and at least an output end section having a larger inner cross-sectional dimension over at least a portion of the output end section than an inner cross-sectional dimension of the outer capillary along a central portion of the hollow-core photonic crystal fiber prior to the output end section. A second optical component includes a hollow-core photonic crystal fiber and a sleeve arrangement.