Fiber Bragg gratings for atom chips

We discuss the fabrication and characterization of fiber Fabry-Perot cavities developed for integrated atom detection on the atom chip. Investigations show that the cavities are suitable for the detection of small numbers of atoms, with restrictions due to absorption in the Bragg gratings. We show that a significant reduction in these absorption losses can be attained by thermal annealing, removing any material limitations to single-atom detection.