Analysis Of The Characteristic Of Linearly Chirped Bragg Gratings And The Application In Optical Communication For Dispersion Compensation

Dispersion is an important factor that impact the optical communication. Chirped fiber grating is considered to be one of the most useful technology for high-bit-rate optical communication. Therefore, it has been a hot topic in recent years. The paper is quite different from the before researches that it defined an apodization sharpness parameter to analysis the spectral response for dispersion compensation instead of only discussing the impact of the apodization function on spectral performance. Through the simulation of time delay, dispersion ,bandwidth etc, to obtain the optimum value of apodization sharpness parameter. The research works in the dissertation are summarized as follows:? The theory and fundamentals of fiber bragg gratings are introduced, including the coupled mode theory and the transfer matrix method.? The spectral response of chirped and apodization gratings such as reflectance spectrum, time delay, dispersion are simulated and compared in order to analysis the characteristic of chirped and apodization gratings.? Dispersion theory and technology for dispersion compensation are introduced in detailed. A typical system used for dispersion compensation is given.? A apodization sharpness parameter is defined. The effect of different apodization sharpness on the spectral response is compared. It is demonstrated that the apodization sharpness parameter plays a more important role in the behavior of the mean dispersion, group delay ripple and some other spectral responses even than the type of apodization profile itself. It will be also shown that an apodization parameter about 0．75 results in better spectral response as minimum group delay ripple impact, minimum deviation from the required dispersion value and so on.? Based on the above research, an optimization process for the apodization sharpness parameter of fiber Bragg grating dispersion compensators is presented. The positive hyperbolic-tangent profile is taken for example and it will demonstrate again that a proper selection of the apodization sharpness parameter can effectively improve the results obtaining minimum deviation of the dispersion from the required value, maximum reflection bandwidth and minimum group delay ripple impact. Owing to the fact that shorter links minimize the group delay ripple amplitude, whereas the longer ones maximize the bandwidth of interest, the influence of the fiber link length is discussed. It will be shown that a fiber link length of 80 km can meet the requirements of group delay ripple impact and bandwidth.