A method for producing a preform for producing a multi-core fiber. The method includes removing a first part-tube segment having a first part-tube segment cross-sectional area from a center of a receiving tube having a receiving tube internal diameter so that the receiving tube has a first core rod receiving cut-out, axially introducing a central filling rod having a filling rod external diameter into the receiving tube so that the receiving tube contains the central filling rod, inserting a first core rod having a first core rod cross-sectional area into the core rod receiving cut-out so that the receiving tube contains the core rod, axially introducing the receiving tube containing the first core rod and the central filling rod into a jacketing tube so as to obtain a jacketing tube containing the receiving tube, and fusing the jacketing tube containing the receiving tube to form the preform.

The present disclosure relates to a MCF, including a plurality of cores, an outer cladding or tube, diffusion barriers, and claddings. The diffusion barriers and claddings are designed so that unwanted migration of dopants from the inner cladding to the outer cladding or tube is reduced, or that unwanted migration of dopants from the cores to the outer cladding or tube is reduced. The doping levels of the various components of the MCF can be controlled in order to reduce dopant migration. The reduction in dopant gradients reduces the migration of dopants and bubbles to the interfaces between the inner claddings, the outer cladding or tube, and the cores.

A glass cane is manufactured by filling a glass tube with a combination of glass structures forming a cross-sectional pattern within the glass tube, to form a preform. The preform is attached to a draw assembly, such as a draw tower. The draw assembly is operated to draw the preform to a reduced-diameter glass cane by passing the preform through a furnace of the draw assembly while pulling the preform or the reduced-diameter glass cane and rotating the preform or the reduced-diameter glass cane.

According to embodiments of the present invention, a fiber preform or an optical fiber is provided. The fiber preform or the optical fiber includes a core region having a plurality of cores, wherein two cores of the plurality of cores are bridged by an air gap, and a cladding arrangement including a first cladding region having a plurality of structures surrounding the core region, and a second cladding region in between the core region and the first cladding region, the second cladding region having a plurality of tubes, wherein at least one split is defined in the second cladding region. According to further embodiments of the present invention, a method for forming the fiber preform, a method for forming the optical fiber, an optical coupler having the optical fiber, an optical combiner having the optical fiber, and an optical apparatus having the optical fiber are also provided.

A preform manufactured by a method which includes removing a part-tube segment from a center of a receiving tube so that the receiving tube has a core rod receiving cut-out which is formed as a remaining annular sector with two opposite edges, axially introducing a central filling rod into the receiving tube so that the receiving tube contains the central filling rod, inserting a core rod in a radial direction from outside into the core rod receiving cut-out between the two opposite edges of the remaining annular sector so that the receiving tube contains the first core rod, axially introducing the receiving tube containing the core rod and the central filling rod into a jacketing tube so as to obtain a jacketing tube containing the receiving tube, and fusing the jacketing tube containing the receiving tube to form the preform.

Optical waveguide cores having refractive index profiles that vary angularly about a propagation axis of the core can provide single-mode operation with larger core diameters than conventional waveguides. In one representative embodiment, an optical waveguide comprises a core that extends along a propagation axis and has a refractive index profile that varies angularly about the propagation axis. The optical waveguide can also comprise a cladding disposed about the core and extending along the propagation axis. The refractive index profile of the core can vary angularly along a length of the propagation axis.

An integrated optical module is provided. The optical module comprises multi optically-coupled channels, and enables the use thereof in an Artificial Neural Network (ANN). According to some embodiments the integrated optical module comprises a multi-core optical fiber, wherein the cores are optically coupled.

A method for producing a preform for producing a multi-core fiber. The method includes removing a first part-tube segment having a first part-tube segment cross-sectional area from a center of a receiving tube having a receiving tube internal diameter so that the receiving tube has a first core rod receiving cut-out, axially introducing a central filling rod having a filling rod external diameter into the receiving tube so that the receiving tube contains the central filling rod, inserting a first core rod having a first core rod cross-sectional area into the core rod receiving cut-out so that the receiving tube contains the core rod, axially introducing the receiving tube containing the first core rod and the central filling rod into a jacketing tube so as to obtain a jacketing tube containing the receiving tube, and fusing the jacketing tube containing the receiving tube to form the preform.

This application relates generally to an optical fiber for the delivery of infrared light where the polarization state of the light entering the fiber is preserved upon exiting the fiber and the related methods for making thereof. The optical fiber has a wavelength between about 0.9 m and 15 m, comprises at least one infrared-transmitting glass, and has a polarization-maintaining (PM) transverse cross-sectional structure. The infrared-transmitting, polarization-maintaining (IR-PM) optical fiber has a birefringence greater than 10.sup.5 and has applications in dual-use technologies including laser power delivery, sensing and imaging.

The disclosure provides a method of manufacturing a multicore optical fiber comprising a plurality of cores and a common cladding covering each of the plurality of cores and having a non-circular cross-sectional shape capable of passive alignment. The method includes providing an optical fiber preform having a cross-sectional shape delimited by a line obtained by replacing a part of a circumference with one chord or two chords parallel to each other, and applying a drawing tension to one end of the optical fiber preform to draw a multicore optical fiber. An aspect ratio x of the cladding defined by a ratio of a radius of a circle defining the circumference to a distance from the center of the circle to the chord and a drawing tension y are set so that the common cladding has a depression at the center of a plane corresponding to the one or each of the two chords.