Four-port integrated polarizing beam splitter

In this Letter, we report on the first integrated four-port polarizing beam splitter. The device operates on the principle of mode evolution and was implemented in a silicon-on-insulator silicon photonics platform and fabricated on a 300 mm CMOS line using 193 nm optical immersion lithography. The adiabatic transition forming of the structure enabled over a 150 nm bandwidth from λ ∼ 1350 to λ ∼ 1500 nm, achieving a cross-talk level below -10 dB over the entire band.