Polarization-insensitive 1 × 2 Multi-mode Interference Coupler on SOI

We demonstrate a polarization-insensitive multimode interference (MMI) coupler on SOI platform with 220 nm top silicon. The minimum feature size of the device is 235 nm. The simulated and measured excess losses for TE/TM modes at 1550 nm are 0.07 dB/0.08 dB and 0.16dB/0.12dB, respectively. Over the C band, the device exhibits an excess loss of less than 0.5 dB and 0.8 dB in simulation and measurement, respectively.