AMPLITUDE MASK FOR WRITING LONG-PERIOD GRATINGS

摘要

Long-period gratings are written more quickly and at higher intensities by amplitude masks having shadow-forming patterns that scatter, redirect, or otherwise divert shadow portions of radiation used for writing the gratings instead of blocking the shadow portions by absorption or reflection. The shadow-forming masks can be formed along transparent base optics by arrays of diffusers, diffractors, or refractors that relatively divert different portions of the radiation.