Yeh P, Taylor H F
Appl Opt. 1980 Aug 15;19(16):2848-55. doi: 10.1364/AO.19.002848.
Frequency-selective optical couplers in which a periodic perturbation in refractive index induces contradirectional power transfer in parallel single-mode waveguides are analyzed. Expressions for the spectral response are obtained by solving the coupled-mode equations. It is shown that by varying the amplitude of the periodic perturbation along he direction of propagation, the sidelobes present for the case of a uniform perturbation can be substantially reduced. Calculations are made of the mode propagation constants and coupling parameters for two rectangular-core waveguides with a periodic surface corrugation in the region between them. By using these results, design parameters and theoretical performance characteristics for a coupler with high transfer efficiency, low cross talk, and low reflection efficiency in the primary waveguide are determined.
分析了频率选择光耦合器，其中折射率的周期性微扰在平行单模波导中引起反向功率传输。通过求解耦合模方程得到了光谱响应的表达式。结果表明，通过沿传播方向改变周期性微扰的幅度，可以显著降低均匀微扰情况下出现的旁瓣。对两个矩形芯波导之间区域具有周期性表面波纹的情况进行了模式传播常数和耦合参数的计算。利用这些结果，确定了具有高传输效率、低串扰和初级波导中低反射效率的耦合器的设计参数和理论性能特性。
