When excimer laser irradiate phase masks, the periodic fringe patterns are formed in near-field, exposing fiber to it, in core gratings can be induced.

• 准分子激光照射相位掩模后，在近场形成周期的条纹分布，利用近场光强对光敏光纤进行曝光，可以在纤芯中写人光栅。