A Cross-Band Quantum Light Source Based on Spontaneous Four-Wave Mixing in a Shallow-Ridge Silicon Waveguide

Abstract To fully utilize the resources provided by optical fiber networks, a cross-band quantum light source generating photon pairs, where one photon in a pair is at C band and the other is at O band, is proposed in this work. This source is based on spontaneous four-wave mixing (SFWM) in a piece of shallow-ridge silicon waveguide. Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width, enabling broadband photon pair generation by SFWM across C band and O band. The spontaneous Raman scattering (SpRS) in silicon waveguides is also investigated experimentally. It shows that there are two regions in the spectrum of generated photons from SpRS, which could be used to achieve cross-band photon pair generation. A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated, through which cross-band photon pair generation is demonstrated experimentally. The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides. This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks.