色散阶变光纤正常色散区啁啾演变特性之讨论

EVOLUTION OF CHIRP IN THE NORMAL DISPERSION REGION OF STEPWISE DECREASING DISPERSION PROFILED FIBER

利用傅里叶变换法得到了色散阶变光纤正常色散区群速度色散导致啁啾的解析表达式；而且，采用数值法模拟了色散阶变光纤正常色散区啁啾演变过程结果表明：色散阶变光纤中啁啾以色散缓变光纤中啁啾为中心跳跃式变化，但远小于常规光纤中啁啾选择合适入射脉冲初始啁啾会使净啁啾等于零。

An analytic expression is obtained for the chirp induced by the dispersion in the normal dispersion region of stepwise decreasing dispersion profiled fiber by means of Fourier transform algorithm.Using numerical method,we simulate the evolution of chirp in the stepwise decreasing dispersion profiled fiber.The results show that the chirp in the stepwise decreasing dispersion profiled fiber vary jumpingly centring around the chirp in the fiber with slowly decreasing dispersion,howeverit is smaller than chirp in the normal fiber.The net chirp is equal to zero with selecting the suitable initial chirp and the dark soliton can be formed in the stepwise decreasing dispersion profiled fiber.