Two-Photon Interference Across Three Frequency Modes via N-way Bragg Scattering

Controllable higher-dimensional quantum systems have broad applications including quantum advantage in simulation, quantum metrology, and quantum communication. We propose and study an all-to-all interaction between N photons using Bragg-scattering four-wave mixing. Our fiber platform is capable of achieving 95% conversion efficiency between two frequency modes 800 GHz apart at 1280 nm [1,2]. By phase matching an additional mode, we experimentally demonstrate interaction between three optical frequency modes. Using this system to measure correlations between the three modes, we observe two-photon interference in both the classical and quantum regime. We show theoretically that reconfiguring the pumps through successive interactions can yield any N-dimensional unitary circulant matrix, and provide directions to scale this system beyond three channels.

1) Stephane Clemmen, Alessandro Farsi, Sven Ramelow, and Alexander L. Gaeta. Ramsey Interference with Single Photons. Physical Review Letters, 117(22):223601 (2016).

2) Chaitali Joshi, Alessandro Farsi, Stephane Clemmen, Sven Ramelow, and Alexander L. Gaeta. Frequency multiplexing for quasi-deterministic heralded single-photon sources. Nature Communications, 9(1):847 (2018).