Experimental demonstration of all-optical 1×2 quantum routing

Using a quantum switching technique based on a two-photon coherence swapping, we experimentally demonstrate an all-optical 1×2 quantum routing, where the observed switching time of ∼5μs is two orders of magnitude faster than the carrier lifetime or the population relaxation time. Owing to the nonabsorption resonance and its enhanced nonlinearity, the observed switching efficiency (intensity ratio of switch-out signal to switch-in signal) is as high as 10%. Such an efficient and fast optical routing method has the potential to hyperterahertz all-optical quantum routers, where semiconductor quantum wells or quantum dots are chosen as the optical medium with a spin dephasing time in the range of picoseconds.