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Unclad optical fibers based on Ge–Sb–S glass systems were prepared by preform drawing. It was shown that optical losses in fibers depend on the content of limiting impurities in glass. The correlation between the level of optical losses in fibers and the content of gas-forming dissolved impurities and heterophase inclusions in glasses was established. The minimum optical losses were equal to 300 dB/km at 5.35 μm wavelength in fiber from Ge 25 Sb 10.5 S 64.5 glass prepared using chemical-distillation melt purification.

The spectral migration of energy among the Nd 3+ ions in fluoroarsenate glasses of the Na 4 As 2 O 7 , BaF 2 , YF 3 system with different Nd 3+ concentrations (0.5, 2, 3, 4, and 5 mol%) has been investigated by using time-resolved fluorescence line narrowing (TRFLN) spectroscopy. The features of the time-resolved fluorescence line narrowing 4 F 3/2 → 4 I 9/2 emission spectra obtained under resonant excitation at different wavelengths along the 4 I 9/2 → 4 F 3/2 transition as a function of Nd 3+ concentration reveal the existence of energy migration between discrete regions of the inhomogeneously broadened spectral profile. The analysis of the time evolution of the 4 F 3/2 → 4 I 9/2 narrowed emission shows that the electronic mechanism responsible for the ion–ion interaction can be identified as a dipole–dipole energy transfer process. From the thermal behavior of lifetimes of the 4 F 3/2 state a T 3 dependence for the non-radiative Nd–Nd relaxation processes has been found in the 10–80 K temperature range for Nd 3+ concentrations higher than 0.5 mol% which is in agreement with a two-site non-resonant process.

We report frequency modulation spectroscopy measurements performed on erbium doped fluoride glasses: PZG (39% PbF 2 , 19% ZnF 2 , 42% GaF 3 ) and ZBAC (57% ZrF 4 , 34% BaF 2 , 5% CeF 3 , 4% AlF 3 ). For the ZBAC glass, no changes of lifetime in channel waveguides versus bulk were observed as well as no pump power dependence from 1 to 100 mW. On the contrary, for the PZG glass, the lifetime of the 4 I 13/2 level was reduced from 7 ms in bulk to 2 ms into the waveguides. In this glass, upconversion effects appear very efficient at high incident pump power.

Novel fluorophosphate glasses containing a heavy concentration of Tb 3+ ions are studied in terms of optical absorption and emission, and decaytimes. From the 5 D 4 emitting level, an intense green luminescence is observed. The decay is single-exponential whatever the terbium concentration which can be as large as 36 mol%. At high concentrations, a fast diffusion process is responsible for the energy migration from that level. For 5 D 3 , on the other hand, emissions are strongly concentration-dependent, and the decays are well accounted for by the Inokuti-Hirayama model.

A resonant technique, based on the sinusoidal modulation of the pump beam intensity, is demonstrated in the case of the precise measurement of the lifetime of the 4 I 13 2 level of erbium ions in fluorophosphate hosts. This intensity modulation is obtained via a rotation of the polarization of the pump beam. The large signal-to-noise ratio enables the use of low pump power and apparent lifetime shortenings due to ion-ion energy transfer processes and to amplification of spontaneous emission are circumvented. A parallel ith decay times deduced from usual fluorescence decay measurements is performed. Extension of the method to the spectroscopy of other rare-earth ions is discussed.

Fluoride glasses involved in the realization of laser sources are described. Observed lasing wavelengths, which range from the blue to the mid infrared in fluoride glass optical fibers are reviewed. Also, recent results on planar waveguides, including fabrication and optical properties, are presented.