Ultra-Broadband Double-Layered Polarization Rotator by Inverse Design and 193-nm DUV Lithography

We experimentally demonstrated an integrated polarization rotator using always-feasible inverse design and 193-nm DUV lithography. An experimental peak insertion loss of -0.41 dB and $1-\mathrm{dB}$ bandwidth of $\gt100 \mathrm{~nm}$ can be obtained.