Shaping the spectral correlation of bi-photon quantum frequency combs by multi-frequency excitation of an SOI integrated nonlinear resonator.

We reveal the generation of a broadband (> 1.9 THz) bi-photon quantum frequency comb (QFC) in a silicon-on-insulator (SOI) Fabry-Pérot micro-cavity and the control of its spectral correlation properties. Correlated photon pairs are generated through three spontaneous four-wave mixing (SFWM) processes by using a co-polarized bi-chromatic coherent input with power P1 and P2 on adjacent resonances of the nonlinear cavity. Adjusting the spectral power ratio r = P1/(P1 + P2) allows control over the influence of each process leading to an enhancement of the overall photon pair generation rate (PGR) µ(r) by a maximal factor of µ(r = 0.5)/µ(r = 0) ≈ 1.5, compared to the overall PGR provided by a single-pump configuration with the same power budget. We demonstrate that the efficiency aND of the non-degenerate excitation SFWM process (NDP) doubles the efficiency a1 ≈ a2 of the degenerate excitation SFWM processes (DP), showing a good agreement with the provided model.

AlGaAs-on-insulator waveguide for highly efficient photon-pair generation via spontaneous four-wave mixing.

We report on the generation of correlated photon pairs in AlGaAs-on-insulator (AlGaAs-OI) waveguides through nonlinear spontaneous four-wave-mixing (SFWM). Our measurements reveal an SFWM pair generation efficiency of ∼0.096×1012pairs/(sW2) at a wavelength of 1550 nm. This is one of the highest efficiencies achieved to date for integrated SFWM sources. A maximal coincidence-to-accidental ratio of ∼122 is measured. A spectral characterization of the device's pair emission at the quantum level demonstrates a broad generation bandwidth of 2.0 THz, which is important for frequency multiplexing applications. Our results indicate that AlGaAs-OI is an efficient material platform for integrated quantum photonics at telecom wavelengths.