A Novel Method of All‐Optical Switching: Quantum Router

Subpicosecond all‐optical switching method based on the simultaneous two‐photon coherence exchange is proposed and numerically demonstrated. The optical switching mechanism is based on the optical field induced dark resonance swapping via nondegenerate four‐wave mixing processes. For potential applications of ultrafast all‐optical switching in fiber‐optic communications, 10‐THz channel number independent quantum router is discussed.