根据耦合模理论,分析了多芯光纤支持的超模,推导了超模场分布函数的解析表达式,并利用柯林斯(Collins)公式计算这些超模光束的二阶矩,分析各超模的光束质量。为了获得较好质量的光束输出,还对利用塔尔博特腔进行多芯光纤激光器的模式选择进行了数值分析。计算结果表明,只要选择合适的距离参量,塔尔博特腔可以有效地进行模式选择。

The supermode in multicore fiber was analyzed by using coupled-mode theory, and analytical expression for the mode distribution in multicore fiber was derived. The beam quality of the supermode were numerically calculated. Among all the supermodes, only the in-phase mode has preferable far-field intensity distribution, and mode selection scheme using Talbot cavity was proposed and studied numerically on the isometric and ring distribution multicore fiber lasers. The results show that the in-phase mode can be selected effectively in Talbot cavity using appropriate parameters.