Amplitude mask patterned on an excimer laser mirrorfor high intensity writing of long period fibre gratings

Abstract

Masks have been produced for long period fibre grating fabrication from commercial dielectric laser mirrors. The masks, which were produced by direct patterning of a photoresist using an argon laser, can withstand in excess of 200 mJ/cm2 per 15 ns pulse of 248 nm laser light. The use of these masks decreased exposure times by 90% and nearly doubled the attenuation (dB) of a long period grating produced by a given UV fluence compared to chrome-on-silica masks.