HOLOGRAPHIC METHODS FOR PHASE MASK AND FIBER GRATING FABRICATION AND CHARACTERIZATION

摘要

The fiber grating fabrication based on use of the phase masks is the most stable and accurate manufacturing technology. This paper presents a brief overview of holographic methods of phase masks and fiber Bragg gratings (FBGs) writing and characterization with emphasis on the chirped gratings. We discuss the range of FBG parameters enabled by current technological methods, as well as the relation between the accuracy of FBG parameters and the performance of FBG-based dispersion compensators. While holographic phase mask and FBG writing principles have much in common, the phase mask and FBG production is a unified technology where the quality of the FBG is determined by numerous factors in the process of fabrication. As one of the significant factors, we study the effect of mirror non-flatness on the group delay ripple of chirped FBG. The quality of phase masks and FBGs is often important to characterize directly. In this paper we consider holographic side-diffraction methods of their characterization, which are very accurate and provide the information that is not simple to obtain from spectroscopic measurements.