Inverse Design of a SiPh Y Splitter

Overview:

This project uses the Lumerical suite and the Lumopt API to optimize the design of an optical y-splitter using topology optimization. The Y-splitter is designed for a wavelength of 1.55μm, with dimensions of 2.9x3.9 μm. The topology optimizer has a built-in filter for the DFM stage, which corresponds to a minimum-feature size of around R/2. For the displayed optimization runs, the R value used was 200nm.

Optimization Process

The LumOpt topology optimization library was used to conduct the optimization, using the Mode Match figure of merit.

The output shows complete binarization, while conforming to a minimum feature size that is specified by the filter value.

Results

Upon completion of the optimization, the resulting forward optimized topology was analyzed using the Lumerical port objects to find the S parameters. The input return loss of the splitter (S11) has a magnitude of 1x10^-4, indicating low refelction. The magnitude of the transmission S21 has a normalized power transmission of approximately 0.93. The results are shown in the logarithmic plot below.

The power transmission pattern and field propagation pattern are shown below