Theoretical Study On The Linearly Chirped Fiber Bragg Grating And Dispersion Compensation

Fiber Grating is quickly developing in optical communication realm and widely using in many scopes .In optical communication systems ,Fiber Grating and apparatus made of Fiber Grating are necessary .The fiber dispersion is serious and become a main holdback along with the development of optical communication. So many people focus on it. At present, Linear chirp Fiber Grating is the most effective and useful prolect of compensating fiber dispersion because of its good characteristics. Such as low wastage,little bulk,low price,big dispersion compensation.In this thesis , the author firstly detailed analyze the optical characteristics of fiber gratings using the coupled-mode theory.Secondly,describe the transfer matrix method---a common method to solve the nouniform fiber gratings. Then introduce the uniform fiber grating,linear uniform chirped fiber grating,apodized chirped fiber grating step by step, and a detailed comparision of their optical characteristics is made.The characteristics of apodized functions constructed by the author are abundantly discuss.According to the best apodized enveloped conditions, the best apodized functions constructed by the author are decided to the fiber grating systems which the chirped coefficient and the length are known. At the same time, the author model the spectral characteristics of the linear chirped fiber grating apodized by the self-constructed functions,some useful conclusions about the fiber grating optical characteristics are gained when changing the grating parameters. All the conclusions are of practical meaningful to design the fiber grating compensators. The modeling results tell us that, apodized by the functions constructed by the author, the reflection spectrum of the linear chirped gtating has a wide bandwidth, and well restrains the oscilation of the delay curve and the dispersion curve, moreover,the delay curve keeps enough time delay. All show that the optical characteristics of the apodized functions constructed by the author are good.To the theory of fiber gratings used as dispersion compensation ,the author makes a more detailed analysis. The author compensates the dispersion after light propagates 100 kilometre in normal single-mode fiber by using the linear chirped fiber grating apodized by Gauss function and self-constructed function, other parameters are the same(under these parameters, 10Gb/s dispersion compensation signal transmission has been realized ). Simulations show that: to the broaden pulses, the performance of compensation of linear chirped grating apodized by the functions constructed by the author is much more better others.At last I summarize my thesis.