Fiber Bragg gratings for dispersion compensation in optical communication systems

This paper presents an overview of fiber Bragg gratings (FBGs) fabrication principles and applications with emphasis on the chirped FBG used for dispersion compensation in high-speed optical communication systems. We discuss the range of FBG parameters enabled by current fabrication methods, as well as the relation between the accuracy of FBG parameters and the performance of FBG-based dispersion compensators. We describe the theory of the group delay ripple (GDR) generated by apodized chirped fiber gratings using the analogy between noisy gratings and superstructure Bragg gratings. This analysis predicts the fundamental cutoff of the high frequency spatial noise of grating parameters in excellent agreement with the experimental data. We review the iterative GDR correction technique, which further improves the FBG quality and potentially enables consistent fabrication of FBG-based dispersion compensators and tunable dispersion compensators with unprecedented performance.