Low-cost amplitude mask for long-period grating fabrication

A novel method is presented that use the RZJ-304 positive photoresist to construct an array as amplitude mask to writing long period gratings, and for a protective effect when fabricate aluminum ring array as amplitude mask. Results show that the long period gratings’ transmission spectra are good with different types of processing methods. In this way, the processing methods we demonstrate are suitable for processing long period gratings.