Dispersion-engineered SOI waveguide-based telecom-band quantum light sources

The development of telecom-band integrated quantum light sources is an essential step towards deploying large-scale all-optical quantum computation and fiber-based communication networks. SOI (silicon-on-insulator) waveguides are more amenable to on-chip integration due to the low-cost and mature fabrication technology, and smaller device footprint as compared to chi⁽²⁾ waveguides. Silicon’s high nonlinear coefficient along with a narrow and well-defined spontaneous Raman spectrum are added advantages for building quantum light sources with high spectral brightness and purity. Here, we theoretically explore quantum state engineering for direct generation of spectrally-pure (purity ~ 95%) heralded single photons, and also broadband (~60-nm around 1550-nm) polarization-entangled photon pairs (concurrence>0.96), at telecom wavelengths by tailoring the waveguide dispersion in silicon nano-waveguides and optimizing other parameters like pump wavelength and bandwidth.