Study On The Phase-Sampled Fiber Grating And Its Application For Dispersion And Dispersion Slope Compensation

Fiber Bragg grating (FBG) is one of the most important fundamental components in optical communication and optical sensors system. With the development of dense wavelength division multiplex (DWDM), the theoretical and experimental study of phase-sampled FBG has been very popular. Compared with amplitude-sampled FBG, phase-sampled FBG has one more adjustable factor-grating phase, so the design of phase-sampled FBG is more flexible. The phase-sampled grating has many new characteristics, so it has more potential in its fufure application.By the theoretical study, phase-sampled FBGs have been classified as two kinds by the sample function: (1) both amplitude and phase sampled FBG, (2) purely phase-sampled FBG. At present, researches aiming at phase-sampled FBG focus on the application of multi-channel filter. But the research On the application of dispersion and dispersion slope compensator has been done not very much. The designs for optimization the purely phase-sampled FBG mostly are using genetic algorithm and simulated annealing algorithm. But the parameters of the two methods are difficult to choose and the algorithm structures are more complicated.On the study of both amplitude and phase sampled FBG, by introducing multiple phase shifts after each sample in the sampled FBG can dense the channel spacing, and investigated the phase shifts method and Talbot effect are equivalent for densifying the channel spacing of sampled FBG. The numerical calculation showed that multiple phase shifts sampled FBG can densify the channel spacing while keeping delay characteristics of all channels, and the dispersion and dispersion slope can be compensated simultaneously provided the sampling period is chirped linearly along the chirped sampled grating.On the study of purely phase-sample FBG, the sample function of the purely phase-sampled FBG is optimized based on the particle swarm optimization method, the method is simple and faster convergence. Through the method, the peak reflectivity is nearly the same for all channels, and we demonstrate that both the dispersion and dispersion slope can be compensated by adjusting the chirp in the grating period and the chirp in the sampling period.