为了实现激光器在一定温度范围内LD泵浦源免温控稳定工作, 具有较高并且稳定的泵浦光吸收效率, 分析了DPL激光器中LD发射谱和Nd: YAG增益介质吸收谱的特点及匹配问题, 据此提出了一种激光器免温控泵浦源的多波长选择理论和方法, 同时增加泵浦光吸收长度克服Nd: YAG吸收谱和LD波长失配的不利影响。优化设计了一个波长为802.35 nm@25 ℃、813.15 nm@25 ℃和810.95 nm@25 ℃的三波长LD泵浦方案, 计算结果表明: 在一定吸收长度下, 多波长泵浦光吸收效率可达73.96%, 并且在-15.7~65.7 ℃宽温度波动范围内, 激光器输出能量不稳定度优于5%。同时还模拟分析了增益介质吸收长度和掺杂浓度对泵浦光吸收效率的影响。

To make the laser diode(LD) pump source of laser operate reliably in a wide ambient temperature range without temperature control system, and improve the absorption efficiency and stability of the pump light, the spectral properties of LD and the absorption spectrum properties of Nd: YAG were analyzed, then a new theory and method to design LD pump source with multi-wavelength were proposed, and the absorption length in the gain media was increased to overcome the disadvantage produced by the mismatch between the LD wavelength and the absorption peak of Nd: YAG. A LD pump source with three wavelengths(802.35 nm@25 ℃, 813.15 nm@25 ℃ and 810.95 nm@25 ℃) was designed. The simulation result shows that the pump light absorption efficiency can reach 73.96% under a certain absorption length, and while the ambient temperature changes from -15.7 ℃ to 65.7 ℃, the instability of the output energy is less than 5%. The influence of the absorption length and the doped concentration of Nd3+ in the laser crystal on the pump light absorption efficiency was also simulated.