Efficient O-band emission from Pr³⁺ doped low phonon energy ZnF₂-based glasses

Pr3+ doped ZnF2-based (ZnF2-BaF2-SrF2-YF3) glasses with a low phonon energy of similar to 420 cm(-1) are prepared by using a conventional melt-quenching method in dry N-2 atmosphere. Under the excitation of a 980 nm laser diode, intense emission at similar to 1310 nm is observed from the Pr3+ doped ZnF2-based glasses. The full spectral width at half maximum is 107 nm (1275-1382 nm), which is similar to 7 nm wider than that of Pr3+ doped ZrF4-based glass (similar to 100 nm, 1279-1379 nm). The measured lifetime (similar to 183 mu s) of the excited energy level (1)G(4) for Pr3+ ions in the ZnF2-based glass is also much longer than that of Pr3+ doped in ZrF4-based glass (similar to 110 mu s). According to the theoretically calculated results, a positive gain of 31.7 dB at 1304 nm can be obtained from O-band optical amplifiers based on the Pr3+ doped ZnF2-based glass, which is 5 dB higher than that obtained from amplifiers based on Pr3+ doped ZrF4-based glass with a same pump condition. The corresponding bandwidth for a net gain of >20 dB is similar to 51 nm (1277-1328 nm), and the noise figure is calculated to be < 5.8 dB in above spectral range. Our results indicate that Pr3+ doped ZnF2-based glasses have the potential for constructing efficient O-band optical amplifiers.