Fluoride glasses: fibers

The numerous lasing wavelengths that have been observed with fluoride glass fibers are shown in Table 4. Each of them is characterized by the highest output power reported to date, and by the pumping conditions, either direct or through up-conversion. 

Characteristics of rare-earth-doped ZBLAN fluoride glass fiber lasers, (i) incident, (1) launched, and (a) absorbed pump powers, (uc) up-conversion pumping... 

Because of the wide transmission range and low phonon energies of fluoride glasses, the observation of numerous rare-earth laser lines is possible at wavelengths beyond 2 fim, where the transmission of silica fibers is extremely poor. Laser sources around 2 /jm are of special interest because they belong, not only to the eye-safe spectral domain, but also to an optical transparency window of the atmosphere. Two fluoride glass fiber lasers have been demonstrated in that region. First, a Ho3+ laser with the 5I7 -> 5I8 transition at 2.024 /on which delivers 250 mW with 60%... 

Other sensing applications include water sensing by direct absorption of the 3H4 —> 3F4 transition of Tm3+ at 1.47 /an [259] and alcohol sensing by evanescent wave in undoped fluoride glass fibers [260]. 

Less optimistic predictions have been advanced by France et al. (1987), who estimated 3.5 x 10 dB/km for ZrF -based glass fibers at A 2.55 pm, by taking into account the predicted effects of extrinsic absorption such as that due to transition metal ions, certain lanthanide ions and OH ions. The intrinsic value of attenuation has already been achieved in practice for v-Si02 at 0.16 dB/km for A = 1.55 pm(Miyaetal. 1979). Figure 16a shows an actual measurement for a fluoride glass fiber prepared at the Naval Research Laboratory (NRL), Washington, DC, USA... 

Aggarwal, I.D. and Lu, G. (Eds.) (1991) Fluoride Glass Fiber Optics, Academic Press, Boston. Contains a series of chapters written by leading experts in the field detailing the structure, processing, and properties of fluoride glasses and their application as optical fibers and use in other optical devices. 

Polyethylene, low-density Stannic chloride glass etching/frosting Potassium bifluoride Potassium fluoride glass fiber mfg. 

H. Tokiwa, Y. Mimura, T. Nakai and 0. Shinbori, Fabrication of long single-mode and multi-mode fluoride glass fibers by the double crucible technique. Electronics Letters, 21 [24], 1130-1131 (1985). 

Anti-Stokes lasers in fluoride glass fibers... 

In fluoride glass fibers anti-Stokes lasers are favored for three reasons ... 

Polyvinylidene fluoride Glass fiber — Film covering aircraft interior components... 

While there are many reports on sol-gel-derived oxide glass fibers, few works have been done on fluoride glass fibers. Fiber drawing of multi-component precursor oxide gels and their fluorination appear to be much less viable. Heavy-metal fluoride glass fibers are usually produced by the preform drawing technique. 

Ultra low-loss applications of fluoride glass fibers has not been realized because of problems associated with microcrystallization, crucible contamination and bubble formation during fiber fabrication. Nevertheless, fibers with losses greater then than lOdB/km are routinely obtained and can be used for chemical sensor applications, as well as high power UV, visible and IR laser transmission. Fluoride glasses are used in some lasers used for dentistry for the replacement of the mechanical drill. This is due to the fact that they deliver very well the Er-YAG laser wavelength (2.94 pm). 

Table 11.2 efficient emissions of rare-earth ions observed in fluoride glass fiber lasers or... 

---