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

在室温下，我们观察到Ni掺杂Li_2 O-Ga_2 O_3-SiO_2玻璃的宽带发射，其带宽为300 nm，覆盖了从O到L带的光谱范围。在退火的Li_2 O-Ga_2 O_3-SiO_2玻璃中观察到了这种宽带发光。我们阐明了这种宽带发光的来源是玻璃中Ni^<2+>占据LiGa_5O_8纳米尖晶石晶体中的八面体位置。发射寿命在5 K时约为440 μsec，随着温度的升高而降低，在300 K时为240 μsec。发射带为<2g><2g>八面体Ni^&lt;2+&gt;离子的向下d-d ^3 T ^3F → ^3A^3F跃迁。发射量子效率约为10%。研究了掺Bi锂铝硅酸盐玻璃的近红外宽发射特性，并对掺Bi锂铝硅酸盐玻璃的近红外宽发射特性进行了研究。结果表明，玻璃的发射峰波长和宽度可以通过激发波长来控制。在900 nm激发下，发射光谱的半高宽（FWHM）最宽，超过500 nm。发射覆盖了从920到2000 nm以上波长的光谱范围。带宽超过1000 nm。当玻璃在974 nm激发时，获得的发射量子效率为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.