玻尔兹曼分布对Yb^(3+)掺杂光纤激光器波长的分析

Analysis of the Spectrum of Yb^(3+) Doped Fiber Laser with Boltzmann Distribution

Yb^(3+)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Yb^(3+)在玻璃基质中的能级,利用玻尔兹曼分布,计算了Yb^(3+)离子在~2F_(7/2)和~2F_(5/2)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~2F_(7/2)各Stark能级上粒子数相对比率随温度变化的曲线。结合Yb^(3+)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Yb^(3+)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 fromYb^3＋-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 Yb^3＋in the glass matrix,we calculate the Boltzmann factors of Yb^3＋on different Stark levels of ~2F_（7/2） and ~2F_（5/2） by using Boltzmann distribution.And then on the results,the variations of particle population on different ~2F_（7/2） Stark levels with the temperature are studied.Combined with the diagram of the emission and absorption cross section of Yb^3＋,it can thus be concluded that,in the longer wavelength range（1 130~1 200 nm）,the Yb^3＋-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.