线性啁啾长周期光纤光栅用作EDFA增益平坦滤波器的理论研究

Linearly Chirped Long Period Gratings Used for EDFA Gain Flattening

提出用具有特定折射率调制包络的线性啁啾长周期光纤光栅作为掺铒光纤放大器(EDFA)的增益平坦滤波器.采用龙格库塔迭代法数值求解该类型光栅耦合模方程,就特定的掺铒光纤放大器增益谱,用Nelder-Mead优化算法对光栅结构参量(光栅长度、周期、线性啁啾系数、折射率调制包络的形状等)进行优化,设计出能在C波段35nm带宽范围内对掺铒光纤放大器进行平坦化(增益起伏在±0.5dB之内)的平坦滤波器.

The linearly chirped long period grating with special refractive index for EDFA gain flattening is presented. Runge-Kutta algorithm is used to numerically solve the coupled-mode equations of this type of grating. The grating structure parameters including grating length, period, linear chirp coefficient and the core refractive index profile are optimized by Nelder-Mead arithmetic. A linearly chirped long period grating with appropriate parameters is designed to flatten the gain spectrum of EDFA. The flattened gain spectrum has a bandwidth of 35 nm in C wave band and a fluctuation in ±0.5 dB.