Splitting Indistinguishable photons: Using Linear Optics to exceed the limit of Photon Blockade

Photonics has been established as an attractive platform for quantum information processing. However, lack of photon-photon interactions prevents the implementation of certain desirable quantum operations. Scattering photons off a mediator such as a Two-Level Emitter (TLE) coupled to a waveguide has been shown to create photon-photon interactions. However, time-energy uncertainty prevents the implementation of high-fidelity quantum operations with a single TLE. For example, the photon blockade effect exhibited by a TLE is unable to deterministically route two indistinguishable input photons to different output ports. We show that the use of optimized linear optics can be used to tune the inference between the output modes of the TLE to improve beyond the limitation imposed by photon blockade. Via numerical optimization, this limit can be exceeded to reach net routing efficiencies approaching 92%. Since the interference introduced by linear optics strongly correlates to the temporal profile of the incident photons, we employ wave shaping to further maximize the routing efficiency. Our results prove that systems built with TLEs and linear optics open up prospects of achieving high fidelity quantum operations.