Perspective: Molten core optical fiber fabrication—A route to new materials and applications

Abstract

The molten core method, whereby a precursor core phase melts at the draw temperature of the cladding glass that encapsulates it, has proven to be a remarkably versatile approach to realize novel optical fibers. Employed globally for both scientific inquiry and practical applications, it is arguably the only approach that leads to long lengths of novel material fiber with both crystalline and glassy cores. This article reviews the history of the process, the ever-broadening range of compositions, the unique applications that have been enabled, and provides a perspective on current challenges and future opportunities.

Overview of high temperature fibre Bragg gratings and potential improvement using highly doped aluminosilicate glass optical fibres

“…The fibre investigated in this study, which is refered as 'YAG-derived fibre,' was fabricated using the molten core method. More details regarding the fabrication process can be found in [71]. In short, a rod-shaped yttrium aluminium garnet (YAG) crystal of 2.75 mm diameter and 60 mm length was inserted inside a F300 pure silica glass capillary tube (3 mm and 30 mm inner and outer diameters, respectively).…”

Ge-capped SiGe core optical fibers

“…The SiGe core material with a silica cladding were prepared by the molten core fiber drawing method [11] at a temperature of ∼1950°C. Prior to loading, the inner surface of the silica cladding tube was coated with a thin interfacial layer of Ca(OH) 2 to reduce interactions between the silica cladding and the molten semiconductor [12].…”

Fiber Integrated Wavelength Converter Based on a Silicon Core Fiber With a Nano-Spike Coupler

“…The converter was fabricated from SCFs that were produced via the molten core drawing (MCD) method, as detailed in Refs. [11], [15]. Using this method, tens of meters of SCFs were drawn with silicon core/silica cladding diameters of ∼ 5.5 µm/144 µm.…”

“…Silicon core fibers (SCFs) are emerging as an alternative nonlinear platform that combines the benefits of the fiber geometry with the advantages of the highly nonlinear silicon material systems [10]. These fibers can be fabricated using conventional drawing tower procedures, but the core sizes produced via this method are typically on the order of ∼ 10 µm [11]. To obtain the few micrometer sized cores required for nonlinear applications, a post-draw tapering procedure has been recently developed [12].…”