Sopori B L, Phillips C M, Chang W S
Appl Opt. 1980 Mar 1;19(5):790-801. doi: 10.1364/AO.19.000790.
A new method for high-efficiency interconnection of two planar optical waveguides is described. This technique is based on mode-matched coupling and is particularly useful when the difference between the refractive indices of the individual guides is large. The method consists of etching a deep vertical step in the highindex waveguide followed by the deposition of low-index waveguide on the etched section so that the two guides remain connected end to end. A theoretical treatment for the design of the coupler and for determination of fabricational tolerences is given. Couplers were fabricted using high-index waveguides like GaAs and LiNbO(3) and low-index waveguides made up of glass or solution-deposited (polyurethane or photoresist) films on SiO(2) substrate. It is shown that by controlling the junction profile, efficiencies close to theoretical values can be obtained. Some applications of such a coupler are given.
描述了一种用于两个平面光波导高效互连的新方法。该技术基于模式匹配耦合，当各个波导的折射率差异较大时特别有用。该方法包括在高折射率波导中蚀刻一个深垂直台阶，然后在蚀刻部分上沉积低折射率波导，以使两个波导端对端保持连接。给出了耦合器设计和制造公差确定的理论处理方法。使用诸如砷化镓和铌酸锂之类的高折射率波导以及由玻璃或在二氧化硅衬底上溶液沉积（聚氨酯或光刻胶）膜制成的低折射率波导制造了耦合器。结果表明，通过控制结的轮廓，可以获得接近理论值的效率。给出了这种耦合器的一些应用。
