Tm^(3+)/Ho^(3+)共掺硫系玻璃光纤放大器增益特性

Gain Characteristics of Tm^(3+)/Ho^(3+)-Co-doped Chalcogenide Glass Fibers

中红外2.0～3.5μm波段激光在医疗、空气污染监测和军事等领域有着重要的应用前景。采用真空熔融淬冷法制备了Tm3+/Ho3+共掺的Ge20Ga5Sb10S65硫系玻璃,测试了样品的吸收光谱以及800nm激光泵浦下的荧光光谱,通过Judd–Ofelt和Mc-Cumber理论计算了Tm3+/Ho3+的辐射寿命、自发辐射几率和受激发射截面等光谱参数。在此基础上,研究了双掺离子之间的能量传递和Tm3+–Ho3+的多种跃迁过程,给出了详细的4能级系统的速率方程,并结合光功率传输方程,得出Tm3+/Ho3+共掺硫系玻璃光纤放大器在2μm波段的增益特性。数值模拟结果表明:Tm3+/Ho3+共掺硫系玻璃光纤在2μm波段的增益值达27dB,增益带宽为112nm,最佳掺杂光纤长度L=300cm,所需泵浦功率Pp=200 mW,可用于2μm波段宽带放大。

The mid-infrared （2-3.5 μm） emission has potential applications in medical surgery, atmosphere pollution monitoring and military. The Tm3＋/Ho3＋ ions doped Ge20GasSb10S65 chalcogenide glasses were prepared by a vacuumed melt-quenching method. Their refraction index, absorption spectra and emission spectra were measured. The spontaneous emission probability, radiative life- time and emission cross-section were calculated based on the Judd-Ofelt and the Mc-Cumber theories. On the basis of the energy transfer and various transitions between Tm3＋ and Ho3＋ ions, a four-level rate equation was proposed. The 2 tan gain properties of Tm3＋/Ho3＋ co-doped chalcogenide glass fiber amplifier were simulated and analyzed by the proposed and the light propagation equa- tions. The amplifier feasibility exhibits a high gain and a wide bandwidth. The simulated results show that the maximum signal gain is 27 dB, and the gain width is 122 nm.