S-shaped polymer waveguides are heavily exploited to connect optical components. Reducing the bending loss of S-shaped polymer waveguides is critical for low-loss and small-size optical circuits. In this paper, the S-shaped waveguide with offsets and trenches (SW-OT) is designed. The dependence of the bending loss on crucial parameters like offsets, trench locations and trench widths is analyzed by the beam propagation method. A comparison of the bending loss among standard S-bend, shifted S-bend, S-bend employing trenches and SW-OT structure is conducted. Results show that the bending loss of the SW-OT with a bending radius of 1000μm is only 0.11dB, reducing by 89.70% compared with the S-shaped waveguide with only shifts. Moreover, a dramatic reduction in the bending loss is obtained by placing trenches properly in the curved region. Therefore, the combination of offsets and trenches can effectively decrease the bending loss of low index contrast polymer S-shaped waveguides.

S 形聚合物波导被大量用于连接光学元件。降低 S 形聚合物波导的弯曲损耗对于低损耗和小尺寸光路至关重要。在本文中，设计了具有偏移和沟槽的 S 形波导（SW-OT）。通过光束传播方法分析了弯曲损耗对偏移、沟槽位置和沟槽宽度等关键参数的依赖性。对标准 S 型弯曲、移位 S 型弯曲、采用沟槽的 S 型弯曲和 SW-OT 结构之间的弯曲损耗进行了比较。结果表明，弯曲半径为1000μm的SW-OT的弯曲损耗仅为0.11dB，与仅移位的S形波导相比降低了89.70%。此外，通过在弯曲区域适当地放置沟槽，可以显着降低弯曲损耗。所以，