Regenerated gratings

Abstract

Strong regenerated gratings with a maximum grating strength exceeding (40–50) dB are fabricated inside an optical fibre by bulk macro thermal processing ∼ 900°C using a UV-laser seeded Bragg grating. Further annealing between 1000°C and 1100°C leads to a stabilised grating ∼ 18 dB in strength. This suffers no further degradation at 1100°C for the period monitored, over 4 hours. The potential resolution of this process is demonstrated by regenerating two complex profiles. Phase information is retained between seed and regenerated structures. This opens the way for nano-engineering of materials using thermal processing and seed templates.