Molten core fabrication of bismuth germanium oxide Bi₄Ge₃O₁₂ crystalline core fibers

Abstract

Optical fibers possessing a crystalline oxide core have significant potential for novel and useful electro‐ or nonlinear‐optic waveguides. Presently, however, their utility suffers from the slow speed and limited cladding materials afforded by conventional crystal‐fiber‐growth techniques. Described herein is the development of single phase bismuth germanium oxide crystalline core fibers using conventional glass fiber drawing. More specifically, fibers were fabricated and evaluated based on 2 embodiments of the molten core method. In a first approach, a Bi4Ge3O12 single crystal was employed as the precursor and sleeved inside a borosilicate glass cladding. In the second approach, additional Bi2O3 was included along with the Bi4Ge3O12 precursor single crystal. Glass clad fibers drawn from the precursor Bi4Ge3O12 single crystal resulted in a polycrystalline core with various crystal morphologies (line‐like, dendrite‐like, and uniform grains) as will be discussed, while fibers drawn from the Bi4Ge3O12 single crystal surrounded by Bi2O3 resulted in a more homogeneous microstructure. The eulytine crystal structure was crystallized using both approaches, with the formation of a secondary crystal phase using the second approach. More particularly, this work aims at showing that single phase and phase pure crystalline oxide core optical fibers can be achieved using conventional glass fiber draw processes, although further optimization is necessary for obtaining single crystalline core fibers.

Multiphase Transition toward Colorless Bismuth–Germanate Scintillating Glass and Fiber for Radiation Detection

“…Bismuth–germanate (BGO) is particularly attractive owing to its significance as the material candidate in high-energy physics, radiochemistry, nuclear physics, medicine imaging, and high-energy physics. − As a typical example, it accounted for 50% of the 256 million market for nuclear medical imaging. , The commercial BGO material is usually in the form of single crystal and has demonstrated its outstanding properties such as high density, nonhydroscopic, and super ray absorption ability. − ,, Although there is substantial progress in the crystal growth technique, it has been difficult to achieve a tiny array structure which is critical for construction of a panel detector . The attempts to overcome this limitation include employing the advanced crystal fiber drawing method or machining the bulk crystal into crystal fiber via a top-down approach.…”

Powder-in-Tube Reactive Molten-Core Fabrication of Glass-Clad BaO-TiO2-SiO2 Glass–Ceramic Fibers

“…On the other hand, reactive molten-core fabrication has proven to be an effective method to fabricate fibers with core materials which cannot be drawn into fibers on their own [22][23][24]. With the housing material reacting with the core material via various mechanisms, such as reactive chemistry, dissolution, and diffusion, fibers with various core materials, such as semiconductors, special glass, and crystalline oxides, have been reported [22][23][24][25][26][27][28][29][30]. Therefore, in this paper we report on the fabrication of glass-clad BTS glass-ceramic fibers using the powder-in-tube reactive molten-core approach with a successive isothermal heat treatment.…”