Silicon-photonics-based optical switch with low polarization sensitivity

A polarization-independent optical switching system capable of rerouting light signals is disclosed. The system includes a plurality of switching cells, each including a pair of bus waveguides that are formed in different planes above a substrate. Each bus waveguide supports low-loss propagation of both the TE- and TM-polarization modes and are optically decoupled when the switch is in an unswitched state. In its switched state, a shunt waveguide that also supports low-loss propagation of both polarization modes is moved into proximity with both bus waveguides to form a pair of adiabatic directional couplers that enable the light signal to evanescently couple between each bus waveguide and the shunt waveguide. As a result, the path of a light signal through the switching cell is reconfigured.