高功率激光二极管阵列端面抽运大口径片状放大器抽运场评价方法

Evaluating Specifications on Coupled Pump Distribution in Laser Diode Array End-Pumped Large-Aperture Amplifiers

在高功率激光二极管阵列(LDA)端面抽运大口径放大器研究中,高效均匀的抽运耦合系统是非常重要的.为了对各种抽运耦合系统进行比较,需要对抽运场分布实现量化评价.依据抽运场分布提出一套评价方法,利用沉积效率、平均抽运密度、调制度、起伏均方根(RMS)值、均匀区尺寸等五项指标对抽运场分布进行综合评价.评价方法中既有统计量(如沉积效率、起伏RMS值、平均抽运密度),又有极值量(如调制度),还有建立在起伏RMS值统计结果基础上且满足一定条件的均匀区尺寸指标,是一套比较综合的评价方法.还提出从抽运场中间小区域开始,逐步向外扩大面积计算各指标,最后得到这些指标的变化曲线,根据这些变化曲线可对不同的耦合系统进行分析比较.对三个抽运场分布进行实例分析,结果表明,提出的评价指标和计算方法能反映出抽运场分布的抽运能沉积效率和分布起伏等关键信息.

In laser diode array （LDA） end-pumped large-aperture amplifiers, coupling system with high efficiency and uniform pump distribution is very important. To evaluate different coupling systems, a set of evaluating specifications is put forward, including depositing efficiency, mean pump intensity, modulation, fluctuation root-mean-square （RMS） and size of uniformly pumped region. In these specifications, depositing efficiency, mean pump intensity and fluctuation RMS are statistical variables, and modulation is extreme variable. Dimension index of uniformly pumped region under certain conditions is obtained based on the statistical variable fluctuation RMS. A new method of calculating these values is put forward. The variation curves of these indices are obtained through calculating the pumping area gradually. When the analyzed region is as large as the whole pumping region, varying trends of these specifications can be given out. Using these trends, different coupling methods can be compared. Calculating example of there different pumping fields shows that this set of specifications is comprehensive and is valuable to assess different coupling systems.