利用遗传算法优化线性啁啾光栅性能

针对制作町用于40 Gb/s全光色散补偿的宽带线性啁啾光栅时出现带内群时延纹波波动较大等问题.提出了一种通过设计和改变切趾函数的参量来优化线性啁啾光栅的新方法.该方法实现简单.只需根据需要设计具有不同滚降特性的切趾函数,同时利用遗传箅法来优化切趾参量.结合传输矩阵法经过200代获得了低带内时延纹波的线性啁啾光栅.数值结果验证了采取非对称分段切趾法在保持反射谱宽和平坦性的同时可以抑制带内群时延纹波的优越性.利用该方法制作了反射谱工作带宽为1.06 nm、时延纹波不超过45.60 ps、可用于大容量密集波分复用系统(DWDM)色散补偿的线性啁啾光纤光栅.

Performance Optimization of Linear Chirped Gratings Using Genetic Algorithm

The performance of linearly chirped gratings is optimized by designing and changing the parameters of apodization functions, aiming at some issues such as the unexpectedly fluctuating group delay ripple (GDR) in chirped fiber Bragg grating (CFBG) which are applied to achieving all-optical dispersion compensation in 40 Gb/s optical communications. This method is proposed by selecting some apodization functions with different roll-off characteristics, using genetic algorithm to optimize the apodizing parameters, and combining with transfer matrix method to gain the linearly chirped gratings with low group delay ripple after 200 generations. The numerical results validate the superiority that the ripple occurring in valid bandwidth of flat reflection spectrum can be restrained by adopting asymmetrically partial apodization. Moreover chirped Bragg grating fibers are fabricated of which reflection spectrum bandwidth of 1.06 nm and its delay ripple no more than 45.60 ps, and can be used in dense wavelength division multiplexing system (DWDM) with high capacity.