Study on efficient ultra-broadband optical amplifiers for next generation high capacity optical telecommunication system

我们在室温下观察到了Ni掺杂Li_2O-Ga_2O_3-SiO_2玻璃的宽带发射，其带宽为300 nm，光谱范围从O到L波段。在Li_2O-Ga_2O_3-SiO_2玻璃中观察到了这种宽带发射。阐明了宽带发射来源于玻璃中的LiGa5O8纳米尖晶石晶体中占据八面体位置的Ni~(2+)。发射寿命在5K时约为440μs，在300K时随温度升高至240μs而减小。发射带为八面体Ni^&lt；2+&gt；(^3F)→^3A&lt；2g&gt；(^3F)向下d-d^3T&lt；2g&gt；(^3F)跃迁。发射量子效率约为10%。预计掺镍Li_2O-Ga_2O_3-SiO_2玻璃的性能将超过Ti：Al_2O_3激光材料的性能。研究发现，激发波长可以很大程度上控制玻璃发射的峰值波长和宽度。在900 nm激发下，发射光谱具有最宽的半高宽(FWHM)，大于500 nm。发射的光谱范围从920到2000纳米以上的波长。带宽超过1000 nm。当玻璃在974 nm处被激发时，其发射的量子效率为11%。

We have observed a broadband emission with a bandwidth of 300 nm, which covers the spectral range from the O to L-band, from Ni-doped Li_2O-Ga_2O_3-SiO_2 glass at room temperature. This broadband emission was observed from the annealed Li_2O-Ga_2O_3-SiO_2 glass. We have clarified that the broadband emission originates from Ni^<2+> occupied octahedral sites in LiGa_5O_8 nano-spinel crystals occurred in the glass. The emission lifetime was about 440 μsec at 5 K and decreased with an increase temperature to 240 μsec at 300 K. The emission band was identified as the downward d-d ^3T_<2g>(^3F)→^3A_<2g>(^3F) transition of octahedral Ni^<2+> ions. The emission quantum efficiency is about 10 %. It is expected that the Ni-doped Li_2O-Ga_2O_3-SiO_2 glass has the performance exceeding that of Ti:Al_2O_3 laser material.A broad near-infrared emission of Bi-doped lithium alumino silicate glasses has been investigated. It was found that the peak wavelength and width of the emission from the glasses could be controlled drastically by the excitation wavelength. The emission spectrum had the broadest full width of half maximum (FWHM) of more than 500 nm under the 900 nm excitation. The emission covered a spectral range from 920 to wavelengths over 2000 nm. The bandwidth exceeded 1000 nm. The quantum efficiency of the emission was obtained as 11 % when the glass was excited at 974 nm.