Patent EP-3749992-A2 (EP)
Title: Microstructured multicore optical fibre (mmof), a device and the fabrication method of a device for independent addressing of the cores of microstructured multicore optical fibre
Inventor: NASILOWSKI TOMASZ
IPC: G02B6/02
Filed: 2014-12-15
Abstract: Microstructured multicore optical fibre with a microstructure area, in which, at least two basic cells are embedded, where each of them contains a core, preferably made of glass, specifically including doped silica glass or polymer, together with the surrounding it longitudinal areas with lower refraction index vs. that of the cladding, which areas may adopt the shape of holes, filled with gas, in particular with the air or a fluid or a polymer or spaces of another glass with doping allowing to reduce refractive index(further referred to as holes), embedded in a matrix of glass, in particular of silica glass or polymer. The refraction index of the holes is decreased vs. that of the matrix of glass, in particular of silica glass or polymer. The basic cell is characterised by the diameter of D2 core, the diameter of D3 core and the distance between adjacent holes, corresponding to lattice constant Λ. The centres of the holes are localised on the vertices and the middle points of the sides of the hexagon, the centre of which is designated by the core; the length of side c of the hexagon, created by the centres of holes, is equal to the preferably doubled lattice constant Λ. The juxtaposed, at least, two basic cells are surrounded by the cladding, preferably made of glass, in particular of silica glass or polymer. Device for addressing cores of the multicore optical fibre, characteristic in that it contains single-core, single-mode optical fibres, with parallel layout in the capillary, (further referred to as single-mode optical fibres), in the number, corresponding to the number of the cores of the multicore optical fibre, while the capillary with single-mode optical fibres is connected with the multicore optical fibre, e.g., the microstructured optical fibre, according to this invention, while the cross-sections of the optical fibres in the capillary and the cross- section of the multicore optical fibre are parallel in their configuration. The fabrication method of the device for addressing cores consists in: 1. an analysis of the structure of multicore optical fibre and determination of the number of cores of the multicore optical fibre, the diameter of cores and the distances among them, 2. measurement of the diameters of the cores and of the claddings of single-mode optical fibres, with which the multicore optical fibre is connected, and the scale of tapering of the single-mode optical fibres is deteremined, 3. removal of the cladding of single-mode optical fibres and cleaning their surface, 4. etching, preferably with hydrofluoric acid, the exposed and cleaned fragments of the single-mode optical fibres, so that after their possible tapering and mutual reassembly, the alignment of the cores of the multicore optical fibre was possible with the cores of the single-mode optical fibre, 5. tapering of single-mode optical fibres, according to the calculated scale of tapering, allowing to achieve the diameters of their cores equal to the dimensions of the diameters of the cores of the multicore optical fibre (provided its preferable), 6. preparation of a capillary by its tapering to the size, allowing for insertion of single- mode optical fibres and glass rods, so that the inserted element shad no freedom of movement or that their movement was limited, 7. laying of single-mode optical fibres and glass rods in the capillary, 8. tapering and clamping of the laid and spliced structure in the capillary by its heating and tensing, while, if it is necessary, the multicore optical fibre is also tapered, 9. cleaving the capillary with the laid and spliced structure under right angle to the axis of the longitudinal capillary, preferably with a cleaver for optical fibres with various outer diameters and internal structures, with a possibility of controlled stretching of the fibre, preferably the capillary surface is polished, together with structure, laid in the capillary, 10. cleaving the multicore optical fibre and preferably polishing its surface, 11. orientation of the capillary vs. the multicore optical fibre, together with the structure, laid and welded in its inside, 12. connection of the multicore optical fibre with the capillary and the structure in its inside by means of any disclosed technology, preferably by splicing.