大功率激光二极管双峰结构远场分布模型

A Far-Field Distribution Model Describing the Double-Peak Beam of High-Power Laser Diodes

为了合理地设计光学系统以整形激光二极管出射光束,必须准确了解激光二极管的远场分布,然而对于大功率激光二极管仍没有形式简单并且较好反映实际器件特性的光束模型.基于亥姆霍兹方程的严格远场解,提出使用两个离心高斯光束描述场源处平行结平面方向的模式场分布,将其代入严格远场解中得到一种描述大功率激光二极管远场光分布模型,用于描述其双峰远场结构.理论模型与三种实际器件的测量数据进行了比较,曲线主要部分都能很好吻合,并且偏差部分的能量仅占总能量的1%～2%.该模型数学表达形式简单,可以方便地用于研究光束经光学系统后的变换,以及计算光学系统的耦合效率,而且对于定量设计光学整形系统十分有用.

In order to design optical system to collimate laser beam, its far-field distribution should be acquired exactly. Based on the Helmholtz equation, two decentered Gauss beams are used to represent the distribution of the source in the direction of paralleling the chip plane, then a new model describing the double-peak beam of high-power laser diodes is presented. A comparison with several practical devices is also made, satisfying result has been obtained, the rate of the error power to the total is only 1%～2%. Because of its simple structure, this model can be used to design shaping system or analyze the propagation properties when the laser beam passes through a optic system, and helpful for calculating coupling efficiency.