Heavy metal fluoride glass fibers and their applications

Abstract

The availability of high quality optical fibers with transmission window, larger than that of silica fiber, extends the use of optical fibers and open new application fields. There is increasing demand of optical fiber with transmission over 2 microns, where silica is opaque, for applications as diverse as sensing, fiber lasers and amplifiers, defense (IRCM), spectroscopy… No materials can fulfill all applications needs. Engineers have to make some compromise when choosing the right materials for the right application. Heavy metal fluoride glass is one of these materials. The glass, under bulk form, has a wide transmission window from 0.3 up to 8 microns, without any absorption peaks. Heavy metal fluoride glass fibers are drawn using the preform technique, the same technique used for silica fiber. This technique has proven to allow good control of fiber dimensions and geometry. Fluoride glass fibers with different exotics shapes have already been obtained, such as D-shaped, square, of centered fiber, multi cladding fibers and microstructured fibers…. As far as active fibers are concerned, heavy metal fluoride glasses have low phonon energy and can contain high concentration of active ions, rare-earth elements. Therefore, new laser lines have been already demonstrated using fluoride glass fibers. Fiber lasers with output power exceeding 10 w have been obtained by different groups. This paper will present the latest development of fluoride glass fiber technology, including fibers optical and mechanical properties, fiber lasers and power handling.

Thulium pumped mid-infrared 09–9μm supercontinuum generation in concatenated fluoride and chalcogenide glass fibers

“…The ZBLAN SC can be improved to have a higher IR power and extend further into the infrared to say 4.75μm, as was recently demonstrated [12]. A tellurite or indium fluoride (InF 3 ) [46] fiber with the loss edge at a longer wavelength could be used instead of the ZBLAN fiber. The two approaches each serve to push more power out into the infrared part of the first SC.…”

Multimaterial disc-to-fiber approach to efficiently produce robust infrared fibers

“…Indeed, ChGs can be stably drawn into optical fibers [19] and their spectral transparency window may be readily tuned by compositional engineering [18]. Alternative glasses for the MIR, such as fluoride [20] and tellurite glasses [5,14], do not cover the full MIR spectral range -despite their other attractive features.…”

Review of diverse optical fibers used in biomedical research and clinical practice

“…Glass materials for IR fibers include heavy metal fluorides, [72][73][74] fluoroindates, 75 chalcogenides, 76,77 and heavy metal germinates. 78 Heavy metal fluoride glasses (HMFG) are the only materials that transmit light from UV to mid-IR without any absorption peak.…”

“…[72][73][74][75][76][77][78][79][80][81] Compared to conventional telecom silica fibers, IR fibers usually are more fragile and have larger refractive indices, lower melting or softening points, and greater thermal expansion. Typically, in biomedical photonics, IR fibers are used in lengths <2 to 3 m for fiber optic sensors and optical power delivery applications.…”