Polarization-diversity 4 × 4 Si-wire optical switch

We present a polarization-diversity 4 × 4 silicon-wire optical switch on a 2.1-mm × 1.1-mm die, which employs the TE and TM components but no polarization rotator for simple fabrication. The switch exhibited 12.5 dB on-chip loss, 1.9 dB PDL, and ~10 ps DGD.