摘要
对作为波分复用关键器件之一的刻蚀衍射光栅 (EDG)的像差特性提出了一种简单方便的计算方法 ,分析了像差对刻蚀衍射光栅频谱响应的影响 .理论推导了基于基尔霍夫衍射、角谱衍射以及快速傅里叶变换等方法 .最终证明彗差会造成谱形失称 ,明显降低耦合效率 ;而球差则会明显地增加串扰 .并指出当像差存在时通过输出端加ta per结构 ,并不能显著改善器件的串扰特性 .
A simple and effective method for calculating the wave aberration for an etched diffraction grating (EDG) demultiplexer is presented.The design is analyzed and demonstrated using a Kirchhoff diffraction integral,an angular-spectrum analysis,and a fast Fourier transform method.It is shown that the symmetry of the spectral response and the coupling efficiency will be deteriorated when the coma appears during the diffraction and imaging.The spherical aberration will result in a larger crosstalk as compared to the coma.It is also shown that the crosstalk characteristic can not be improved better by connecting a tapered waveguide at the entrance of each output waveguide of the demultiplexer.
基金
浙江省科技计划资助项目 (编号 :0 0 110 10 2 7)~~
关键词
刻蚀衍射光栅(EDG)
波分复用
波像差
球差
彗差
串扰
耦合效率
etched diffraction grating
wavelength division multiplexing
wave aberration
spherical aberration
coma
crosstalk
coupling efficiency
