According to embodiments, a method of making a microstructured glass article includes bundling M bare optical fibers in a fiber bundle, wherein M is an integer greater than 100. Thereafter, the fiber bundle may be inserted in a cavity of a soot preform. The soot preform may have a density of less than or equal to 1.5 g/cm.sup.3 and comprise silica-based glass soot. The soot preform and inserted fiber bundle may then be consolidated to form a microstructured glass article preform. The microstructured glass article preform may then be drawn into the microstructured glass article comprising M core elements embedded in a cladding matrix.

A method of forming an imaging fibre apparatus comprises arranging rods to form a plurality of stacks each comprising a respective plurality of rods, wherein: for each stack, the respective plurality of rods comprises rods having different core sizes, the rods of different core sizes being arranged in a selected arrangement, and the rods of different core sizes being arranged such that each stack has a respective selected shape; wherein the selected shape or shapes are such that the stacks stack together in a desired arrangement; the method further comprising: drawing each of the plurality of stacks; stacking together the plurality of drawn stacks together in the desired arrangement to form a further stack; drawing the further stack; and using the drawn further stack to form an imaging fibre apparatus, wherein the selected arrangement of the rods in each stack and the selected shape or shapes of the stacks are such that the further stack comprises a repeating pattern of rods of different core sizes.

According to embodiments, a method of making a micro structured glass article 100 includes bundling M bare optical fibers in a fiber bundle, wherein M is an integer greater than 100. Thereafter, the fiber bundle may be inserted in a cavity of a soot preform. The soot preform may have a density of less than or equal to 1.5 g/cm3 and comprise silica-based glass soot. The soot preform and inserted fiber bundle may then be consolidated to form a microstructured glass article preform. The micro structured glass article preform may then be drawn into the microstructured glass article 100 comprising M core elements 102 embedded in a cladding matrix 104.

A method of forming an imaging fibre apparatus comprises arranging rods to form a plurality of stacks each comprising a respective plurality of rods, wherein: for each stack, the respective plurality of rods comprises rods having different core sizes, the rods of different core sizes being arranged in a selected arrangement, and the rods of different core sizes being arranged such that each stack has a respective selected shape; wherein the selected shape or shapes are such that the stacks stack together in a desired arrangement; the method further comprising: drawing each of the plurality of stacks; stacking together the plurality of drawn stacks together in the desired arrangement to form a further stack; drawing the further stack; and using the drawn further stack to form an imaging fibre apparatus, wherein the selected arrangement of the rods in each stack and the selected shape or shapes of the stacks are such that the further stack comprises a repeating pattern of rods of different core sizes.

A gas pressure maintaining and adjusting device, a microstructure optical fiber and a preparation method of the microstructure optical fiber belong to the field of preparation of special optical fibers. In the gas maintaining and adjusting device, a communication control module is electrically connected with a main console of an optical fiber drawing tower; a signal output end of the communication control module is connected with a signal receiving end of a programmable logic controller (PLC); the PLC is provided with a gas pressure threshold display screen; the signal receiving end of the PLC is further connected with a signal output end of a pressure controller; and the PLC is further connected with an electromagnetic valve used for controlling opening and closing of a gas inlet and a gas outlet.

A method of forming an imaging fibre apparatus comprises: •arranging core rods 102 and cladding rods 104 to form at least one primary stack 100a, each primary stack 100a comprising a plurality of core rods 102 and cladding rods 104 arranged in a stack arrangement thereby to form a plurality of core regions within a cladding region; •performing a drawing process to form a plurality of drawn stacks from the at least one primary stack; •wherein the plurality of core rods and cladding rods are further arranged to have a selected shape such that the plurality of stacks stack together in a desired arrangement and wherein the stack arrangement comprises an at least partial outer layer of cladding rods thereby to provide separation between core regions of respective adjacent stacks when stacked in the desired arrangement, the method further comprising: •stacking the plurality of drawn stacks together in the desired arrangement to form a further stack; •drawing the further stack; and •using the drawn further stack to form an imaging fibre apparatus.

According to embodiments, a method of making a micro structured glass article 100 includes bundling M bare optical fibers in a fiber bundle, wherein M is an integer greater than 100. Thereafter, the fiber bundle may be inserted in a cavity of a soot preform. The soot preform may have a density of less than or equal to 1.5 g/cm3 and comprise silica-based glass soot. The soot preform and inserted fiber bundle may then be consolidated to form a microstructured glass article preform. The micro structured glass article preform may then be drawn into the microstructured glass article 100 comprising M core elements 102 embedded in a cladding matrix 104.

A multi-core fiber includes: a plurality of cores; and a cladding portion formed around outer peripheries of the cores. Further, the cores each have a propagation characteristic conforming to any one of a plurality of standards for optical propagation characteristics, and of the cores, cores that are closest to each other conform to standards different from each other.

A method of manufacturing a multicore fiber includes: an initial-preform forming process of forming an initial preform by arranging in an array a plurality of core rods each including a core portion and a cladding portion formed around outer periphery of the core portion; and an optical fiber manufacturing process of manufacturing an optical fiber from the initial preform. Further, the core rods include a plurality of holes, and the core rods are arranged in a manner that one hole is arranged between two core portion adjacent to each other in the initial-preform forming process.

A preform (10) for an antiresonant hollow core optical fibre comprises an outer jacket tube (12) having an inner surface and a central longitudinal axis (24); a plurality of antiresonant cladding tubes (14) spaced apart at predefined peripheral locations around the inner surface of the outer jacket tube (12), each antiresonant cladding tube (14) in contact with the inner surface such that a central longitudinal axis (26) of each antiresonant cladding tube (14) is at a first radial distance from the central longitudinal axis (24) of the outer jacket tube (12); and a plurality of spacing elements (22) disposed alternately with the antiresonant cladding tubes (14) and each in contact with an outer surface of each of two adjacent antiresonant cladding tubes (14) at one or more contact points (28), the contact points (28) at a second radial distance from the central longitudinal axis (24) of the outer jacket tube (12), the second radial distance being greater than the first radial distance.