为了降低光波导中的弯曲损耗，从理论上分析了光波导的弯曲损耗、过渡损耗产生的根源，并以此为依据推导出符合弯曲、过渡低损耗的5次，6次，7次，8次和9次幂函数表达式。由MATLAB和MAPLE工具软件计算可知，9次幂函数的图形曲线最圆滑，当取h=125μm，L=800μm(高分支比)时其弯曲损耗可以减小到4.57dB，与传统常用的余弦函数和反正弦函数进行比较，在相同条件下弯曲损耗有了明显的降低。结果表明，所设计的1×4光功分器优化路线，传输性能优良，分配均匀。这为以后Y分支光波导的制作有很好的指导意义。

In order to reduce the bending loss of optical waveguide, the source of bending loss and transition loss of optical waveguide was analyzed. A series of curved line expression were obtained, i.e., five-power function, six-power function, seven-power function, eight-power function and nine-power function expression. With the help of MATLAB and MAPLE, calculation results show that the curves of the nine-power function is the most smooth, when taking h=125μm, L=800μm (high branching ratio), the loss can be reduced to 4.57dB, which is much smaller than conventional sine function and cosine functions. At last, an optimum route composed of 1×4 optical splitters was designed and simulated in which the energy distribution was symmetric and uniform. This can offer some valuable guidance to the research of Y-type optical waveguide.