Achievement

Next-generation photonic quantum networks will require switches that operate with low loss, low signal-band noise, and without disturbing the transmitted photons spatial, temporal, or polarization degrees of freedom. Furthermore, it is desirable for such a quantum network to utilize the existing telecommunications infrastructure. These networks must also be able to route entangled photons at high speeds, with minimal loss and signal-band noise, and, most importantly, without disturbing the photons quantum state. An all-optical quantum switch was designed and constructed which fulfills these daunting requirements and characterized its performance at the single photon level, utilizing the methods of quantum-state tomography.