In this paper, low-loss Y-branch splitters up to 128 splitting ratio are designed, simulated, and optimized by using 2D beam propagation method in OptiBPM tool by Optiwave. For an optical waveguide, a silica-on-silicon material platform is used. The splitters were designed as a planar structure for a telecommunication operating wavelength of 1.55 $\mathrm{\mu }$m. According to the minimum insertion loss and minimum non-uniformity, the optimum length for each Y-branch is determined. The influence of the pre-defined S-Bend waveguide shapes (Arc, Cosine, Sine) and of the waveguide core size reduction on the splitter performance has been also studied. The obtained simulation results of all designed splitters with different S-Bend shape waveguides together with the different waveguide core sizes are discussed and compared with each other.

在本文中，使用Optiwave OptiBPM 工具中的2D 光束传播方法设计、模拟和优化了高达128 分光比的低损耗Y 分支分光器。对于光波导，使用硅上二氧化硅材料平台。分路器设计为平面结构，用于电信工作波长为 1.55$\mathrm{\mu }$米。根据最小插入损耗和最小非均匀性，确定每个 Y 分支的最佳长度。还研究了预定义的 S 弯曲波导形状（弧、余弦、正弦）和波导芯尺寸减小对分路器性能的影响。讨论并比较了所有设计的具有不同 S 弯曲形状波导以及不同波导芯尺寸的分路器的仿真结果。