Yb3+掺杂光纤激光器输出的激光波长范围很宽,但是获得不同波长激光的难易程度不同。为了在长波长波段获得较强的激光输出,本文分析了激光输出的影响因素。根据Yb3+在玻璃基质中的能级,利用玻尔兹曼分布,计算了Yb3+离子在2F7／2和2F5／2各个Stark能级的玻尔兹曼因子的数值。并利用这一结果,绘出了基态2F7／2各Stark能级上粒子数相对比率随温度变化的曲线。结合Yb3+离子的吸收和发射截面得出结论:在长波长谱段,随着温度的升高,能够获得1 130～1 200nm波长谱段较高功率的激光输出。同时也指出在Yb3+掺杂光纤激光器的常规激光输出波段,输出功率随着温度的升高而降低。

The working wavelength output fromYb3+-doped fiber lasers is in a wide range,but the degree of the difficulty to get some selected wavelength is different. For example,it is difficult to get high power laser output in a longer wavelength. In this work,the factors that influenced on the output of the laser are analyzed. According to the energy level of Yb3+ in the glass matrix,we calculate the Boltzmann factors of Yb3+on different Stark levels of 2F7／2 and 2F5／2 by using Boltzmann distribution. And then on the results,the variations of particle population on different 2F7／2Stark levels with the temperature are studied. Combined with the diagram of the emission and absorption cross section of Yb3+,it can thus be concluded that,in the longer wavelength range (1 130～1 200 nm),the Yb3+-doped fiber lasers can work with the high power laser output with the increase in temperature,but instead,the output power decreases in the common wavelength.