  Entanglement is a valuable resource in quantum information technologies. The
practical implementation of entangled photon sources faces obstacles from
imperfections and defects inherent in physical systems, resulting in a loss or
degradation of entanglement. The topological photonic insulators, however, have
emerged as promising candidates, demonstrating an exceptional capability to
resist defect-induced scattering, thus enabling the development of robust
entangled sources. Despite their inherent advantages, building programmable
topologically protected entangled sources remains challenging due to complex
device designs and weak material nonlinearity. Here we present a development in
entangled photon pair generation achieved through a non-magnetic and tunable
anomalous Floquet insulator, utilizing an optical spontaneous four-wave mixing
process. We verify the non-classicality and time-energy entanglement of the
photons generated by our topological system. Our experiment demonstrates a
substantial enhancement in nonclassical photon pair generation compared to
devices reliant only on topological edge states. Our result could lead to the
development of resilient quantum sources with potential applications in quantum
technology.
