Low-polarization-sensitive 1 × 2 carrier-injection-type silicon photonic switch consisting of input-/ output-side polarization splitter/rotators and a single Mach-Zehnder interferometer

We propose a low-polarization-sensitive 1 × 2 carrier-injection-type silicon photonic switch consisting of a single Mach-Zehnder interferometer, an input-/output-side polarization splitter and rotators, bidirectional light injection, and an external optical circulator. A polarization-dependent loss (PDL) of 1.3 dB was achieved using the proposed structure, whereas a PDL exceeding 17 dB was observed without the structure. In addition, owing to the large birefringence of the silicon waveguide, a differential group delay (DGD) of 10 ps for a 10 Gbps OOK signal was observed. However, a reduced polarization dependence was confirmed through bit error rate measurements, with the power penalty difference lower than 1 dB.