级联Y分支光波导的优化设计

设计了一种适于级联的Y分支结构。因光输入场不对称产生高阶模,且光输入区的畸变而产生的辐射场与导模之间容易发生干涉,这些因素导致Y分支输出不均匀。在输入波导后添加一段起模式过滤作用的窄波导结构,可以在对器件长度及损耗影响很小的情况下,有效滤除高阶模,减小干涉效应,改善器件输出的均匀性。使用该结构设计并优化的1×4分束器,在输入光波长为1.3μm、1.55μm时,器件均匀性可以分别达到0.0191dB和0.0214dB。

Optimized design of cascaded Y-branch waveguide

The design of Y-branch which is suitable for cascaded structures is presented in this paper.The uniformity of Y-branches is affected by high modes and interference effects.High modes are induced by asymmetry of input field and interference effects are due to the field radiated from distortions in the input section.Narrow waveguide after input section can effectively filter out the high modes which cause the ununiformity of Y-branches and has little influence on the length and excess loss of the device.The uniformity of 0.0191dB and 0.0214dB can be respectively achieved with narrow waveguide in 1×4 beam splitter under the input wavelength of 1.3μm and 1.55μm.