3D Polymer Based 1×4 Multimode Interference Splitter

The paper presents the design, simulation, optimization, and fabrication of a 3D optical splitter utilizing multimode interference with four S-Bend outputs. The waveguide channel profile in the splitter design uses polymer IP-Dip, and it is fabricated using 3D laser lithography based on the direct laser writing process. The structure was designed for operation at a telecommunication wavelength of 1.55 μm. The optimal size of the multimode interference splitter and the optimal length of the outputs were determined based on minimum insertion losses and minimum non-uniformity. To demonstrate the 1×4 splitting, the output characteristics were investigated by near-field measurement.