Study of the Characteristics of Few-Mode Microstructured Optical Fibers with 6 Cores Made of Highly Doped GeO₂ Silica and Induced Chirality

Review and perspective on polyhedron model for estimating thermodynamic properties of oxides

“…According to Hanzen, 49 the limitations of the polyhedron method can be listed as follows: (1) The polyhedron method assumes that the properties of a polyhedron (e.g., size, shape, and fictive thermodynamic properties) are constant from one structure to another, (2) the effect of inter-polyhedra linkage ("linkage rigidity") is missing, (3) polyhedron distortions are not allowed from structure to structure (i.e., the energies related to crystal field effects, Jahn-Teller distortions, ion pairs), ( 4) it is simply based on mechanical mixing of polyhedra (i.e., the excess properties of mixing are not predicted), and ( 5) it is only applicable to compounds that can be divided into different polyhedra (i.e., it cannot be applied to covalent sulfides and sulfosalts).…”

“…Thermodynamic modeling of phase equilibria and chemical reactions in multicomponent systems is an indispensable part of the development of advanced materials and processes. Oxide-based materials have many applications, such as glass, 1 ceramics, 2,3 reinforcements in metallic matrix composites, 4 thin films and coatings, 5,6 materials for magnetic recording, 7 fuel cells, 8,9 hightemperature superconductors, 10,11 health, 12,13 cement, 14,15 energy storage, 16,17 water decontamination, 18,19 and process metallurgy. 20,21 Despite the large volume of data available, there are numerous important oxide compounds with unknown thermodynamic properties.…”

Twisted Silica Few-Mode Hollow GeO2-Doped Ring-Core Microstructured Optical Fiber

“…In previously published papers [84][85][86][87][88][89][90], we described in detail all previous successfully performed stages of drawing the tower modifications that provide improvements to the twisting of the fabricated MOF from the initial weak 10 revolutions per meter (rpm) up to 66 rpm [84,85], and then further 100, 400, and 500 rpm [89,90]. We chose to develop the method proposed in [1]: the rotation of the optical fiber preformed during the drawing process.…”

“…At the same time, we tested, verified, and determined the full-cycle technique of the twisted MOF fabrication: from the MOF stack formation, it was redrawn to the MOF cane and then followed the MOF drawing from the cane with twisting under specified excess pressure and at a specified drawing temperature [84,85]. During this stage, we successfully fabricated the following MOFs with twisting from 10 rpm (with a rotation speed of 20 revolutions per minute with an MOF drawing speed of 2 m per minute) up to 66 rpm (with a rotation speed of 200 rpm and an MOF drawing speed of 3 m per minute): hexagonal geometry with shifted core [84,85]; hexagonal geometry, that provides the quasi-ring radial mode field distribution [84,85]; equiangular spiral six-ray geometry [89,90]. Furthermore, by combining the maximal rotor rotation speed of 200 revolutions per minute and a low drawing speed of 0.9 m per minute, the typical hexagonal geometry MOF with a shifted core under the pitch of 0.65…0.700 and 3…4 spatially guided modes were manufactured with twisting of 217 rpm, which was ultimately the maximum chirality order for equipment described above that could be possibly induced.…”

Experimental researches and testing of silica twisted six-GeO2-doped core microstructured optical fiber. Part II: research of fiber Bragg grating responses

“…Earlier on 1 we presented designed and successfully first time fabricated twisted silica microstructured optical fibers with six GeO2-doped cores (6-GeO2-doped core MOFs), placed in the central part of optical fiber cross-section. Primary motivation for implementation on practice of described above twisted multicore MOF was attempt to combine two basic complicated fiber optic structuresmulticore MOFs and twisted MOFsthat should have to add novel unique properties to this new type of optical fibers, according to results, presented in the series of known recently published papers [2][3][4][5][6] .…”