Figure 3: Diagram of the spin-based photonic router.

The control spin directs the signal photon to: (a) port c; (b) port d; (c) superposition of two modes in port c and d. PBS1, PBS2 (polarization beam splitters), λ/2 (wave plate). Note that PBS1 is set to the {|H〉, |V〉} basis and PBS2 to the {|D〉, |A〉} basis.