We review our experiments on the generation and propagation of quantum states of light in topological nanophotonic platforms, specifically, topological protection of biphoton states and path entanglement, and entanglement of different topologies.
The robust generation and propagation of multiphoton quantum states are crucial for applications in quantum information, computing, and communications. Although photons are intrinsically well isolated from the thermal environment, scaling to large quantum optical devices is still limited by scattering loss and other errors arising from random fabrication imperfections. The recent discoveries regarding topological phases have introduced avenues to construct quantum systems that are protected against scattering and imperfections. We experimentally demonstrate topological protection of biphoton states, the building block for quantum information systems. We provide clear evidence of the robustness of the spatial features and the propagation constant of biphoton states generated within a nanophotonics lattice with nontrivial topology and propose a concrete path to build robust entangled states for quantum gates.
The field of topological photonics leverages concepts from geometry and topology – the branch of mathematics that deals with global properties that cannot be changed under continuous deformation – to produce electromagnetic modes that propagate with immunity to certain types of disorder and imperfections. In the last few years, several experiments have achieved the generation and propagation of quantum states of light in these so-called topological modes, demonstrating enhanced robustness of such inherently fragile quantum states. In this talk we will focus on our recent results in this area including topological protection of spatial entanglement and the demonstration of topology as an additional degree of freedom for entanglement using CMOS-compatible silicon photonics platforms.
The efficient generation of non-classical light at the micro- and nanoscale is central to the development of quantum technologies. Integrated photonic structures offer new opportunities for increasing the generation efficiency and control of the quantum state of non-classical light. Recently, photonic structures based on topology conservation have been proposed as platforms to overcome issues associated with disorder and fabrication imperfections. For instance, it has been suggested that topological edge states can be exploited for the generation of photon pairs having robust spectral correlations [1]. More recently, the effect of topology on path correlations of photon pairs generated by spontaneous four-wave mixing (SFWM) in waveguide arrays has also been investigated [2].