光纤光栅非线性对色散特性的影响

通过在能量较高、考虑非线性时,求解光纤光栅非线性耦合模方程连续波条件下的解,得到光纤光栅失谐量δ与光脉冲传播常量q的非线性色散关系和光栅致群速度色散系数βg2与δ的关系.用MATLAB绘图,得到非线性参量γ和光脉冲能量P0的乘积γP0对色散和βg2的影响.结果表明:随着βg2的增加,非线性色散曲线的上、下两支向δ的负值区移动,当超过某一临界值时,曲线上支开始形成环,这时光纤光栅引起的群速度色散中的反常色散区消失,全部变成正常色散.

Effect of Nonlinearity of Fiber Bragg Grating on Dispersive Properties

Through getting the solutions of two nonlinear coupled-mode equations about Fiber Bragg Grating in the condition of continuous wave when nonlinearity is considered, the nonlinear dispersion relation about the detuning of Fiber Bragg Grating δ and the light pulse propagation constant q,the relation about the coefficient of group velocity dispersion induced by Fiber Bragg Grating βg2 and δ was obtained.The curve for influences of the multiplication γP0 of the nonlinear coupling parameter γ and the light pulse energy P0 on dispersion and βg2 by means of plotting with MATLAB was given.The conclusions show that with γP0 increasing the nonlinear dispersion curves shift to the negative region of δ,the upper branch of the curve will form a ring when γP0 exceeds a critical value,while the anomalous dispersion region of group velocity dispersion induced by fiber Bragg grating vanishes,group velocity dispersion becomes only one normal dispersion region.