Presentation Information
[10p-E219-4]Triphoton State Engineering in Cubic Nonlinear Waveguide Arrays
〇(DC)Miguel Yee Bacaoco1, Declan Power2,3, Fereshte Hajiarab1, Denis Ilin1,3, Alexander Solntsev1,3 (1.University of Technology Sydney, 2.University of Sydney, 3.Sydney Quantum Academy)
Keywords:
photon triplets,nonlinear photonics,third-order SPDC
Integrated photonic platforms offer a scalable route to quantum information technologies due to their compatibility with established fabrication processes and room-temperature operation. While photon-pair generation via spontaneous parametric down-conversion (SPDC) in χ² waveguides is well established, direct generation of three-photon states from χ³ nonlinearities remains largely unexplored. We present a theoretical framework for triphoton generation and control through third-order spontaneous parametric down-conversion (TOSPDC) in cubic nonlinear waveguide arrays. Inter-waveguide coupling induces a quantum walk that shapes the three-photon wavefunction without external optical elements. For a two-waveguide system, we show that tuning the phase mismatch and coupling enables all-optical switching and tuning of heralded Bell states. Extending to three waveguides provides access to a larger Hilbert space supporting genuine tripartite entanglement, including GHZ-type states. These results establish a pathway for on-chip triphoton state engineering in χ³ photonic platforms for quantum communication and measurement-based quantum computing.