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

在室温下，我们观察到掺杂ni的li22o - ga_2o_3 - sio_2玻璃在O到l波段有300 nm的宽带发射。在退火后的Li_2O-Ga_2O_3-SiO_2玻璃中观察到这种宽带发射现象。我们澄清了宽带发射来自于玻璃中LiGa_5O_8纳米尖晶石晶体中Ni^<2+>占据的八面体位。发射寿命在5k时约为440 μsec，在300 K时随温度升高而减小至240 μsec。发射带确定为八面体Ni^<2+>离子的向下d-d ^3T_<2g>(^3F)→^3A_<2g>(^3F)跃迁。发射量子效率约为10%。预计掺ni的Li_2O-Ga_2O_3-SiO_2玻璃的性能将超过Ti:Al_2O_3激光材料。研究了双掺杂锂铝硅酸盐玻璃的宽近红外发射特性。结果表明，激发波长对玻璃的峰值波长和发射宽度有明显的控制作用。在900 nm激发下，发射光谱具有大于500 nm的最宽半峰宽（FWHM）。发射的光谱范围从920到超过2000纳米。日志含义带宽超过1000nm。当激发波长为974 nm时，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.