2×2 multimode interference coupler with low loss using 248 nm photolithography

We demonstrate a 2×2 multimode interference coupler in 220 nm silicon photonics, with 3.8 μm by 152 μm footprint. Loss is <0.15±0.01 dB for 1530–1565 nm, across the 200 mm wafer using 248 nm lithography. This is the lowest loss reported for sub-micron silicon 2×2 MMI.